Oxytocin reduces amygdala activity, increases social interactions, and reduces anxiety-like behavior irrespective of NMDAR antagonism.

Science.gov (United States)

Sobota, Rosanna; Mihara, Takuma; Forrest, Alexandra; Featherstone, Robert E; Siegel, Steven J

2015-08-01

Standard dopamine therapies for schizophrenia are not efficacious for negative symptoms of the disease, including asociality. This reduced social behavior may be due to glutamatergic dysfunction within the amygdala, leading to increased fear and social anxiety. Several studies have demonstrated the prosocial effects of oxytocin in schizophrenia patients. Therefore, this study evaluates the effect of subchronic oxytocin on EEG activity in amygdala of mice during performance of the three-chamber social choice and open field tests following acute ketamine as a model of glutamatergic dysfunction. Oxytocin did not restore social deficits introduced by ketamine but did significantly increase sociality in comparison to the control group. Ketamine had no effect on time spent in the center during the open field trials, whereas oxytocin increased overall center time across all groups, suggesting a reduction in anxiety. Amygdala activity was consistent across all drug groups during social and nonsocial behavioral trials. However, oxytocin reduced overall amygdala EEG power during the two behavioral tasks. Alternatively, ketamine did not significantly affect EEG power throughout the tasks. Decreased EEG power in the amygdala, as caused by oxytocin, may be related to both reduced anxiety and increased social behaviors. Data suggest that separate prosocial and social anxiety pathways may mediate social preference. (c) 2015 APA, all rights reserved).

Reducing pressure oscillations in discrete fluid power systems

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

2016-01-01

Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article investi...... investigates how cylinder pressure oscillations may be reduced by shaping the valve opening trajectory without the need for closed loop pressure feedback. Furthermore the energy costs of reducing pressure oscillations are investigated....

Voltage harmonics mitigation through hybrid active power filer

International Nuclear Information System (INIS)

Sahito, A.A.; Tunio, S.M.; Khizer, A.N.

2016-01-01

Fast dynamic response, high efficiency, low cost and small size of power electronic converters have exponentially increased their use in modern power system which resulted in harmonically distorted voltage and currents. Voltage harmonics mainly caused by current harmonics are more dangerous as performance and expected operating life of other power system equipment are affected by harmonically distorted supply voltage. Electronic filter circuits are used to improve system power quality by mitigating adverse effects of harmonics. Hybrid filters having advantages of both passive and active filters are preferred to resolve the problem of harmonics efficiently and avoiding any chance of resonance. In this paper, a three phase three wire network is considered to supply an adjustable speed drive represented by a resistive load connected across a three phase bridge rectifier. Simulation of the considered system shows THD (Total Harmonic Distortion) of 18.91 and 7.61 percentage in supply current and voltage respectively. A HAPF (Hybrid Active Power Filter) is proposed to reduce these THD values below 5 percentage as recommended by IEEE Standard-519. P-Q theorem is used to calculate required parameters for proposed filter, which is implemented through hysteresis control. Simulation results confirm the effectiveness of the designed filter as THD for both current and voltage have reduced below allowable limit of 5 percentage. (author)

Voltage Harmonics Mitigation through Hybrid Active Power Filter

Directory of Open Access Journals (Sweden)

Anwer Ali Sahito

2016-01-01

Full Text Available Fast dynamic response, high efficiency, low cost and small size of power electronic converters have exponentially increased their use in modern power system which resulted in harmonically distorted voltage and currents. Voltage harmonics mainly caused by current harmonics are more dangerous as performance and expected operating life of other power system equipment are affected by harmonically distorted supply voltage. Electronic filter circuits are used to improve system power quality by mitigating adverse effects of harmonics. Hybrid filters having advantages of both passive and active filters are preferred to resolve the problem of harmonics efficiently and avoiding any chance of resonance. In this paper, a three phase three wire network is considered to supply an adjustable speed drive represented by a resistive load connected across a three phase bridge rectifier. Simulation of the considered system shows THD (Total Harmonic Distortion of 18.91 and 7.61% in supply current and voltage respectively. A HAPF (Hybrid Active Power Filter is proposed to reduce these THD values below 5% as recommended by IEEE Standard-519. P-Q theorem is used to calculate required parameters for proposed filter, which is implemented through hysteresis control. Simulation results confirm the effectiveness of the designed filter as THD for both current and voltage have reduced below allowable limit of 5%.

Bi-Level Decentralized Active Power Control for Large-Scale Wind Farm Cluster

DEFF Research Database (Denmark)

Huang, Shengli; Wu, Qiuwei; Guo, Yifei

2018-01-01

This paper presents a bi-level decentralized active power control (DAPC) for a large-scale wind farm cluster, consisting of several wind farms for better active power dispatch. In the upper level, a distributed active power control scheme based on the distributed consensus is designed to achieve...... fair active power sharing among multiple wind farms, which generates the power reference for each wind farm. A distributed estimator is used to estimate the total available power of all wind farms. In the lower level, a centralized control scheme based on the Model Predictive Control (MPC) is proposed...... to regulate active power outputs of all wind turbines (WTs) within a wind farm, which reduces the fatigue loads of WTs while tracking the power reference obtained from the upper level control. A wind farm cluster with 8 wind farms and totally 160 WTs, was used to test the control performance of the proposed...

SPECTROPHOTOMETRIC ASSESSMENT OF FERRIC REDUCING POWER OF THE INSTANT COFFEE

OpenAIRE

Tsiupko, T. G.; Tishchenko, E. A.; Voronova, O. B.

2016-01-01

The methods of antioxidant activity determination of foodstuffs using different indicator systems were discussed. The investigation of ferric reducing power (FRP) of coffee and its individual phenolic components such as chlorogenic (CGA), caffeic (СА), ferulic (FA), gallic (GA), vanillic (VA), protocatechuic (PCA) and uric (UA) acids as well as quercetin (Qu) and catechol (C) using the spectrophotometric method with Fe(III) - o-Phen indicator system was carried out. It was shown that the sens...

Extending OFDM Symbols to Reduce Power Consumption

NARCIS (Netherlands)

Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

2012-01-01

Existing communication standards have limited capabilities to adapt to low SNR environments or to exploit low data rate requirements in a power efficient way. Existing techniques like e.g. control coding do not reduce the computational load when reducing data rates. In this paper, we introduce

Reduced-dimension power allocation over clustered channels in cognitive radios system under co-channel interference

KAUST Repository

Ben Ghorbel, Mahdi

2014-05-12

The objective of this paper is to propose a reduceddimension resource allocation scheme in the context of cognitive radio system in presence of co-channel interference between users. We assume a multicarrier transmission for both the primary and secondary systems. Instead of optimizing the powers over all sub-carriers, the sub-carriers are grouped into clusters of sub-carriers, where the power of each sub-carrier is directly related to the power of the correspondent cluster. The power optimization is done only over the set of clusters instead of all sub-carriers which can significantly reduce the complexity of the resource allocation problem. The performance loss of the reduced dimension solution with respect to the optimal solution, where the optimization is carried over all active sub-carriers, allows trading-off complexity versus performance. Numerical evaluation indeed revealed that a limited performance loss occurs by optimizing over a reduced set of clusters instead of the full optimization in the context of cognitive radio systems.

An Active Capacitor with Self-Power and Internal Feedback Control Signals

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Huai

2017-01-01

This paper proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. A control strategy that does not require any external feedback...... signal is proposed and a self-power scheme for gate drivers and the controller is applied to achieve the two-terminal active capacitor. The concept, control method, self-power scheme, efficiency, and impedance characteristics of the active capacitor are presented. A case study of the proposed active...... capacitor for a capacitive DC-link application is discussed. The results reveal a significantly lower overall energy storage of passive elements and a reduced cost to fulfill a specific reliability target, compared to a passive capacitor solution. Proof-of-concept experimental results are given to verify...

Reducing nitrogen oxides from power stations

International Nuclear Information System (INIS)

Scheller, W.

1986-12-01

The report contains 17 individual lectures of the seminar included in databanks. The lectures concern combustion and waste gas measures for reducing the sulfur dioxide and nitrogen oxide emission from coal-fired and gas-fired power stations. (PW) [de

Review of Active and Reactive Power Sharing Strategies in Hierarchical Controlled Microgrids

DEFF Research Database (Denmark)

Han, Yang; Li, Hong; Shen, Pan

2017-01-01

Microgrids consist of multiple parallel-connected distributed generation (DG) units with coordinated control strategies, which are able to operate in both grid-connected and islanded mode. Microgrids are attracting more and more attention since they can alleviate the stress of main transmission...... systems, reduce feeder losses, and improve system power quality. When the islanded microgrids are concerned, it is important to maintain system stability and achieve load power sharing among the multiple parallel-connected DG units. However, the poor active and reactive power sharing problems due...... in this paper for active power sharing. Moreover, nonlinear and unbalanced loads could further affect the reactive power sharing when regulating the active power, and it is difficult to share the reactive power accurately only by using the enhanced virtual impedance method. Therefore, the hierarchical control...

Regime-based supervisory control to reduce power fluctuations from offshore wind power plants

DEFF Research Database (Denmark)

Barahona Garzón, Braulio; Cutululis, Nicolaos Antonio; Trombe, Pierre-Julien

2013-01-01

Wind power fluctuations, especially offshore, can pose challenges in the secure and stable operation of the power system. In modern large offshore wind farms, there are supervisory controls designed to reduce the power fluctuations. Their operation is limited due to the fact that they imply loss...... that consider different wind power regimes to derive control setpoints by using a Markov-Switching AutoRegressive model. We evaluate the performance versus measured data in terms of power ramp characteristics and energy efficiency....

Agent-based power sharing scheme for active hybrid power sources

Science.gov (United States)

Jiang, Zhenhua

The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

Bringing MapReduce Closer To Data With Active Drives

Science.gov (United States)

Golpayegani, N.; Prathapan, S.; Warmka, R.; Wyatt, B.; Halem, M.; Trantham, J. D.; Markey, C. A.

2017-12-01

Moving computation closer to the data location has been a much theorized improvement to computation for decades. The increase in processor performance, the decrease in processor size and power requirement combined with the increase in data intensive computing has created a push to move computation as close to data as possible. We will show the next logical step in this evolution in computing: moving computation directly to storage. Hypothetical systems, known as Active Drives, have been proposed as early as 1998. These Active Drives would have a general-purpose CPU on each disk allowing for computations to be performed on them without the need to transfer the data to the computer over the system bus or via a network. We will utilize Seagate's Active Drives to perform general purpose parallel computing using the MapReduce programming model directly on each drive. We will detail how the MapReduce programming model can be adapted to the Active Drive compute model to perform general purpose computing with comparable results to traditional MapReduce computations performed via Hadoop. We will show how an Active Drive based approach significantly reduces the amount of data leaving the drive when performing several common algorithms: subsetting and gridding. We will show that an Active Drive based design significantly improves data transfer speeds into and out of drives compared to Hadoop's HDFS while at the same time keeping comparable compute speeds as Hadoop.

Improvement of active filter for HIMAC power sources

Energy Technology Data Exchange (ETDEWEB)

Kumada, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Kubo, Hiroshi; Furuzeki, Shoichiro; Kanazawa, Toru

1996-03-01

For the power sources of the synchrotron electromagnets for the heavy particle beam cancer therapy apparatus HIMAC in National Institute of Radiological Science, in order to stabilize the taken-out beam, the ripple property as low as below 1 x 10{sup -6} is required. As for this electromagnet power sources, various devices were applied to lower ripples, and the required specifications have been satisfied. Also the beam spill is stable, but slight variation has been observed, therefore, by improving the performance of the active filter, the ripples were improved. The specifications of the electromagnet power sources and the whole constitution of the power source system are shown. In the HIMAC power sources, the means for having realized the low ripple performance so far are explained. Those are the absorption of the ineffective power generated from the power sources, the control of the ripples of common made due to the transducer thyristor, and the sure compensation of ripples by the control circuit for the power sources. By adding the band pass filters to the active filter, its characteristics were improved. As the result, 1200 Hz ripple component was reduced by 41 db, thus the sufficient effect was obtained. Hereafter, by the high sensitivity measurement of the current of electromagnets and the evaluation of magnetic fields, the validity will be evaluated. (K.I.)

Active compressor engine silencer reduces exhaust noise

International Nuclear Information System (INIS)

Denenberg, J.N.; Miller, S.K.; Jay, M.A.

1994-01-01

An active industrial silencer on a compressor engine at a Tenneco Gas station has reduced low-frequency 'rumbling' noise by 8 dB during trials while lowering backpressure about 90$. This 8 dB reduction of the piston firing frequency corresponds to a more than 80% decrease in emitted acoustic power. The silencing unit, installed on one of six engines at the station near Eden, N.Y., continues in operation. Based on the results, the manufacturer is identifying additional compressor sites for further tests. This paper reviews this project

Free radical scavenging potential, reducing power, phenolic and biochemical constituents of Porphyra species from India

Digital Repository Service at National Institute of Oceanography (India)

Pise, N.M.; Jena, K.B.; Maharana, D.; Gaikwad, D.; Jagtap, T.G.

. Antioxidant potentials of algae were assessed through phenolic content, 2, 2-diphenyl-1- picrylhydrazyl (DPPH) activity, hydrogen peroxide (H sub(2)O sub(2)), scavenging power and reducing potential. A dose-dependent free radical scavenging action against DPPH...

Impact of thermostatically controlled loads' demand response activation on aggregated power: A field experiment

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam; Marinelli, Mattia; Kosek, Anna Magdalena

2015-01-01

activation. The outcome of this experimental study quantifies the actual flexibility of household TCLs and the consequence for the different parties with respect to power behaviour. Each DR activation method adopts different scenarios to meet the power reduction, and has different impacts on the parameters......This paper describes the impacts of different types of DR (demand response) activation on TCLs' (thermostatically controlled loads) aggregated power. The different parties: power system operators, DR service providers (or aggregators) and consumers, have different objectives in relation to DR....... The experiments are conducted with real domestic refrigerators representing TCL. Activating refrigerators for DR with a delay reduces the ISE (integral square error) in power limitation by 28.46%, overshoot by 7.69%. The delay in refrigerator activation causes reduction in power ramp down rate by 39.90%, ramp up...

A Reduced Wind Power Grid Model for Research and Education

DEFF Research Database (Denmark)

Akhmatov, Vladislav; Lund, Torsten; Hansen, Anca Daniela

2007-01-01

A reduced grid model of a transmission system with a number of central power plants, consumption centers, local wind turbines and a large offshore wind farm is developed and implemented in the simulation tool PowerFactory (DIgSILENT). The reduced grid model is given by Energinet.dk, Transmission...

Wind Farm Active Power Dispatch for Output Power Maximizing Based on a Wind Turbine Control Strategy for Load Minimizing

DEFF Research Database (Denmark)

Zhang, Baohua; Hu, Weihao; Hou, Peng

2015-01-01

Inclusion of the wake effect in the wind farm control design (WF) can increase the total captured power by wind turbines (WTs), which is usually implemented by derating upwind WTs. However, derating the WT without a proper control strategy will increase the structural loads, caused by operation...... in stall mode. Therefore, the WT control strategy for derating operation should be considered in the attempt at maximizing the total captured power while reducing structural loads. Moreover, electrical power loss on the transmission system inside a WF is also not negligible for maximizing the total output...... power of the WF. In this paper, an optimal active power dispatch strategy based on a WT derating strategy and considering the transmission loss is proposed for maximizing the total output power. The active power reference of each WT is chosen as the optimization variable. A partial swarm optimizing...

Grid-Connection Half-Bridge PV Inverter System for Power Flow Controlling and Active Power Filtering

Directory of Open Access Journals (Sweden)

Chih-Lung Shen

2012-01-01

Full Text Available A half-bridge photovoltaic (PV system is proposed, which can not only deal with bidirectional power flowing but also improve power quality. According to varying insolation, the system conditions real power for dc and ac loads to accommodate different amounts of PV power. Furthermore, the system eliminates current harmonics and improves power factor simultaneously. As compared with conventional PV inverter, the total number of active switches and current sensors can be reduced so that its cost is lower significantly. For current command determination, a linear-approximation method (LAM is applied to avoid the complicated calculation and achieve the maximum power point tracking (MPPT feature. For current controlling, a direct-source-current-shaping (DSCS algorithm is presented to shape the waveform of line current. Simulation results and practical measurements also demonstrate the feasibility of the proposed half-bridge PV system.

Power and death: Mortality salience increases power seeking while feeling powerful reduces death anxiety.

Science.gov (United States)

Belmi, Peter; Pfeffer, Jeffrey

2016-05-01

According to Terror Management Theory, people respond to reminders of mortality by seeking psychological security and bolstering their self-esteem. Because previous research suggests that having power can provide individuals a sense of security and self-worth, we hypothesize that mortality salience leads to an increased motivation to acquire power, especially among men. Study 1 found that men (but not women) who wrote about their death reported more interest in acquiring power. Study 2A and Study 2B demonstrated that when primed with reminders of death, men (but not women) reported behaving more dominantly during the subsequent week, while both men and women reported behaving more prosocially during that week. Thus, mortality salience prompts people to respond in ways that help them manage their death anxiety but in ways consistent with normative gender expectations. Furthermore, Studies 3-5 showed that feeling powerful reduces anxiety when mortality is salient. Specifically, we found that when primed to feel more powerful, both men and women experienced less mortality anxiety. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Investigation of decreasing reactor coolant inventory as a mechanism to reduce power during a BWR ATWS

International Nuclear Information System (INIS)

Peterson, C.E.; Chexal, V.K.; Layman, W.; Hentzen, R.D.; Gose, G.C.

1985-01-01

A best-estimate analysis was performed to evaluate the technique of intentionally reducing reactor coolant inventory in order to reduce power during a BWR ATWS event. The ATWS was initiated by closure of the main steam isolation valves. The analysis was performed with the RETRAN-02 computer code utilizing the one-dimensional kinetics option. The one-dimensional cross sections were developed using the SIMULATE-E and SIMTRAN-E computer codes. The MSIV closure transient provides some of the more severe conditions following a postulated failure to scram. In this transient, the only mechanism for removing energy from the vessel is through the safety relief valve system which results in a heating up of the suppression pool fluid. Consequently, the reactor power must be reduced so that the suppression pool temperature limits are not exceeded. Under the proposed emergency procedure guidelines for the ATWS event, the reactor vessel water level will be lowered to reduce system power. This analysis evaluated the dynamic response of the system as the water level was lowered to the top of active fuel evaluation. Correlating the system power and flow patterns to water level was of particular interest in the analysis. Under natural circulating conditions, the system flows, core power, and pressure responses are extremely tightly coupled and the analysis results proved to be very sensitive to the modeling of downcomer, upper plenum, and core regions

A review on power reducing methods of neural recording amplifiers

Directory of Open Access Journals (Sweden)

samira mehdipour

2016-10-01

Full Text Available Implantable multi-channel neural recording Microsystems comprise a large number of neural amplifiers, that can affect the overall power consumption and chip area of the analog part of the system.power, noise, size and dc offset are the main challenge faced by designers. Ideally the output of the opamp should be at zero volts when the inputs are grounded.In reality the input terminals are at slightly different dc potentials.The input offset voltage is defined as the voltage that must be applied between the two input terminals of the opamp to obtain zero volts at the output. Amplifier must have capability to reject this dc offset. First method that uses a capacitor feedback network with ac coupling of input devices to reject the offset is very popular in designs.very small low-cutoff frequency.The second method employs a closed-loop resistive feedback and electrode capacitance to form a highpass filter.Moreover,The third method adopts the symmetric floating resistor the feedback path of low noise amplifier to achieve low-frequency cutoff and rejects DC offset voltage. .In some application we can use folded cascade topology.The telescopic topology is a good candidate in terms of providing large gain and phase margin while dissipating small power. the cortical VLSI neuron model reducing power consumption of circuits.Power distribution is the best way to reduce power, noise and silicon area. The total power consumption of the amplifier array is reduced by applying the partial OTA sharing technique. The silicon area is reduced as a benefit of sharing the bulky capacitor.

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify design, increase efficiency and integration level, reduce product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented. (au)

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael Andreas E.

2005-01-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

Control strategies of active filters in the context of power conditioning

DEFF Research Database (Denmark)

Dan, Stan George; Benjamin, Doniga Daniel; Magureanu, R.

2005-01-01

performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter is studied for current harmonic compensation. The hybrid filter is formed by a single tuned LC filter per phase and a small-rated power three-phase active filter......Active Power Filters have been intensively explored in the past decade. Various topologies and control schemes have been documented aiming at reducing the cost and improving the performance of the compensation system. Hybrid active filters inherit the efficiency of passive filters and the improved......, which are directly connected in series without any matching transformer. The required rating of the active filter is much smaller than a conventional standalone active filter would be. No additional switching-ripple filter is required for the hybrid filter because the LC filter functions not only...

Active power line conditioners design, simulation and implementation for improving power quality

CERN Document Server

Revuelta, Patricio Salmeron; Litrán, Salvador Pérez

2015-01-01

Active Power Line Conditioners: Design, Simulation and Implementation for Improving Power Quality presents a rigorous theoretical and practical approach to active power line conditioners, one of the subjects of most interest in the field of power quality. Its broad approach offers a journey that will allow power engineering professionals, researchers, and graduate students to learn more about the latest landmarks on the different APLC configurations for load active compensation. By introducing the issues and equipment needs that arise when correcting the lack of power quality in power grids

Reducing the metabolic cost of walking with an ankle exoskeleton: interaction between actuation timing and power.

Science.gov (United States)

Galle, Samuel; Malcolm, Philippe; Collins, Steven Hartley; De Clercq, Dirk

2017-04-27

Powered ankle-foot exoskeletons can reduce the metabolic cost of human walking to below normal levels, but optimal assistance properties remain unclear. The purpose of this study was to test the effects of different assistance timing and power characteristics in an experiment with a tethered ankle-foot exoskeleton. Ten healthy female subjects walked on a treadmill with bilateral ankle-foot exoskeletons in 10 different assistance conditions. Artificial pneumatic muscles assisted plantarflexion during ankle push-off using one of four actuation onset timings (36, 42, 48 and 54% of the stride) and three power levels (average positive exoskeleton power over a stride, summed for both legs, of 0.2, 0.4 and 0.5 W∙kg -1 ). We compared metabolic rate, kinematics and electromyography (EMG) between conditions. Optimal assistance was achieved with an onset of 42% stride and average power of 0.4 W∙kg -1 , leading to 21% reduction in metabolic cost compared to walking with the exoskeleton deactivated and 12% reduction compared to normal walking without the exoskeleton. With suboptimal timing or power, the exoskeleton still reduced metabolic cost, but substantially less so. The relationship between timing, power and metabolic rate was well-characterized by a two-dimensional quadratic function. The assistive mechanisms leading to these improvements included reducing muscular activity in the ankle plantarflexors and assisting leg swing initiation. These results emphasize the importance of optimizing exoskeleton actuation properties when assisting or augmenting human locomotion. Our optimal assistance onset timing and average power levels could be used for other exoskeletons to improve assistance and resulting benefits.

Reducing test-data volume and test-power simultaneously in LFSR reseeding-based compression environment

Energy Technology Data Exchange (ETDEWEB)

Wang Weizheng; Kuang Jishun; You Zhiqiang; Liu Peng, E-mail: jshkuang@163.com [College of Information Science and Engineering, Hunan University, Changsha 410082 (China)

2011-07-15

This paper presents a new test scheme based on scan block encoding in a linear feedback shift register (LFSR) reseeding-based compression environment. Meanwhile, our paper also introduces a novel algorithm of scan-block clustering. The main contribution of this paper is a flexible test-application framework that achieves significant reductions in switching activity during scan shift and the number of specified bits that need to be generated via LFSR reseeding. Thus, it can significantly reduce the test power and test data volume. Experimental results using Mintest test set on the larger ISCAS'89 benchmarks show that the proposed method reduces the switching activity significantly by 72%-94% and provides a best possible test compression of 74%-94% with little hardware overhead. (semiconductor integrated circuits)

Reducing power usage on demand

Science.gov (United States)

Corbett, G.; Dewhurst, A.

2016-10-01

The Science and Technology Facilities Council (STFC) datacentre provides large- scale High Performance Computing facilities for the scientific community. It currently consumes approximately 1.5MW and this has risen by 25% in the past two years. STFC has been investigating leveraging preemption in the Tier 1 batch farm to save power. HEP experiments are increasing using jobs that can be killed to take advantage of opportunistic CPU resources or novel cost models such as Amazon's spot pricing. Additionally, schemes from energy providers are available that offer financial incentives to reduce power consumption at peak times. Under normal operating conditions, 3% of the batch farm capacity is wasted due to draining machines. By using preempt-able jobs, nodes can be rapidly made available to run multicore jobs without this wasted resource. The use of preempt-able jobs has been extended so that at peak times machines can be hibernated quickly to save energy. This paper describes the implementation of the above and demonstrates that STFC could in future take advantage of such energy saving schemes.

Recent progress of R and D activities on reduced activation ferritic/martensitic steels

Energy Technology Data Exchange (ETDEWEB)

Huang, Q., E-mail: qunying.huang@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, P.O. Box 1135, Hefei, Anhui 230031 (China); Baluc, N. [CRPP-EPFL, ODGA C110 5232 Villigen PSI (Switzerland); Dai, Y. [LNM, PSI, 5232 Villigen PSI (Switzerland); Jitsukawa, S. [JAEA, 2-4 Shirakata, Tokai-Mura, Ibaraki-Ken 319-1195 (Japan); Kimura, A. [IAE, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Konys, J. [KIT, P.O. Box 3640, 76021 Karlsruhe (Germany); Kurtz, R.J. [PNNL, Richland, WA 99352 (United States); Lindau, R. [KIT, P.O. Box 3640, 76021 Karlsruhe (Germany); Muroga, T. [NIFS, Oroshi, Toki, Gifu 509-5292 (Japan); Odette, G.R. [UCSB, Santa Barbara, CA (United States); Raj, B. [IGCAR, Kalpakkam 603 102 (India); Stoller, R.E.; Tan, L. [ORNL, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Tanigawa, H. [JAEA, Naka, Ibaraki 311-0193 (Japan); Tavassoli, A.-A.F. [DMN/Dir, DEN, CEA Saclay, 91191 Gif-sur-Yvette cedex (France); Yamamoto, T. [UCSB, Santa Barbara, CA (United States); Wan, F. [DMPC, USTB, Beijing 100083 (China); Wu, Y. [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, P.O. Box 1135, Hefei, Anhui 230031 (China)

2013-11-15

Several types of reduced activation ferritic/martensitic (RAFM) steel have been developed over the past 30 years in China, Europe, India, Japan, Russia and the USA for application in ITER test blanket modules (TBMs) and future fusion DEMO and power reactors. The progress has been particularly important during the past few years with evaluation of mechanical properties of these steels before and after irradiation and in contact with different cooling media. This paper presents recent RAFM steel results obtained in ITER partner countries in relation to different TBM and DEMO options.

Series active power filter in power conditioning

Energy Technology Data Exchange (ETDEWEB)

Turunen, J.

2009-07-01

Power quality has become an important issue nowadays for several reasons, e.g. modern society's growing dependence on electricity and the fact that poor power quality may generate significant economic losses in few moments. Probable power quality problems are, e.g. harmonics, flicker, voltage dips and supply interruptions. The power quality may be improved by using filters and compensators.The purpose of this thesis is to research the operation of the series active power filter (SAPF) in power conditioning. Therefore, this thesis presents a comparison of three series hybrid active power filters (SHAPFs) in current harmonics filtering. In addition to this, it is shown how the voltage dip compensation performance of the SAPF is improved in a unified power quality conditioner (UPQC) application.The three SHAPFs included in the comparison are series connected topology (SCT), filter connected topology (FCT) and electrically tuned LC shunt circuit (ETLC). The operating principle of these filters is to direct the harmonic currents produced by the load to flow in the LC shunt circuits instead of the supply. In the case of the SCT this phenomenon is boosted by applying so-called active resistance in the supply branch using the SAPF. In the case of the FCT a similar action is achieved by applying the compensation voltage in series with the LC shunt circuits using the SAPF. In the case of the ETLC the performance of the LC shunt circuit is enhanced by applying so-called active inductances in series with the LC shunt circuit using the SAPF. The SHAPFs are compared by searching for their best current filtering performance using various main circuit and control system configurations and loads. The operation of the SHAPFs is first analysed mathematically. After this, the current filtering performance of the SHAPFs is inspected using simulations and experimental tests. The experimental tests are carried out using SHAPF prototypes. As a result, it is shown that the current

An investigation of decreasing reactor coolant inventory as a mechanism to reduce power during a boiling water reactor anticipated transient without scram

International Nuclear Information System (INIS)

Peterson, C.E.; Chexal, V.K.; Gose, G.C.; Hentzen, R.D.; Layman, W.H.

1985-01-01

Under certain anticipated transient without scram (ATWS) sequences for a boiling water reactor, it would be desirable to reduce system power, particularly where the primary system has been isolated by closure of all main steam isolation valves and is discharging steam through its safety/relief valve system to the suppression pool. Reducing reactor power increases the time available to shut down the reactor by minimizing the heat dumped to the suppression pool and by helping to keep the suppression pool temperature within limits. Under proposed emergency procedure guidelines for the ATWS event, the reactor water level would be lowered to reduce reactor power. The analyses provide an assessment of the power level that would be attained, assuming the reactor operators were to reduce the the downcomer level down to the top of the active fuel

Low Capacitive Inductors for Fast Switching Devices in Active Power Factor Correction Applications

DEFF Research Database (Denmark)

Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

2014-01-01

This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work is to inves......This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work...... is to investigate different winding approaches and identify suitable solutions for high switching frequency/high speed transition PFC designs. A low parasitic capacitance PCB based inductor design is proposed to address the challenges imposed by high switching frequency PFC Boost converters....

Shunt Active-Power-Filter Topology Based on Parallel Interleaved Inverters

DEFF Research Database (Denmark)

Blaabjerg, Frede; Asiminoaei, Lucian; Aeloiza, E.

2008-01-01

In this paper, an interleaved active-power-filter concept with reduced size of passive components is discussed. The topology is composed of two pulsewidth-modulation interleaved voltage-source inverters connected together on the ac line and sharing the same dc-link capacitor. The advantages......, because the power sharing allows one to use a higher switching frequency in each inverter. This paper analyzes the design of the passive components and gives a practical and low-cost solution for the minimization of the circulation currents between the inverters, by using common-mode coils. Several...

A reduced energy supply strategy in active vibration control

Science.gov (United States)

Ichchou, M. N.; Loukil, T.; Bareille, O.; Chamberland, G.; Qiu, J.

2011-12-01

In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings.

A reduced energy supply strategy in active vibration control

International Nuclear Information System (INIS)

Ichchou, M N; Loukil, T; Bareille, O; Chamberland, G; Qiu, J

2011-01-01

In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings

CMOS Active Pixel Sensors for Low Power, Highly Miniaturized Imaging Systems

Science.gov (United States)

Fossum, Eric R.

1996-01-01

The complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology has been developed over the past three years by NASA at the Jet Propulsion Laboratory, and has reached a level of performance comparable to CCDs with greatly increased functionality but at a very reduced power level.

Adaptative Techniques to Reduce Power in Digital Circuits

Directory of Open Access Journals (Sweden)

Bharadwaj Amrutur

2011-07-01

Full Text Available CMOS chips are engineered with sufficient performance margins to ensure that they meet the target performance under worst case operating conditions. Consequently, excess power is consumed for most cases when the operating conditions are more benign. This article will review a suite of dynamic power minimization techniques, which have been recently developed to reduce power consumption based on actual operating conditions. We will discuss commonly used techniques like Dynamic Power Switching (DPS, Dynamic Voltage and Frequency Scaling (DVS and DVFS and Adaptive Voltage Scaling (AVS. Recent efforts to extend these to cover threshold voltage adaptation via Dynamic Voltage and Threshold Scaling (DVTS will also be presented. Computation rate is also adapted to actual work load requirements via dynamically changing the hardware parallelism or by controlling the number of operations performed. These will be explained with some examples from the application domains of media and wireless signal processing.

The Power Quality Compensation Strategy for Power Distribution System Based on Hybrid Parallel Active Power Filters

Directory of Open Access Journals (Sweden)

Rachid DEHINI

2010-12-01

Full Text Available In this paper, the main aim is to confront the performance of shunt active power filter (SAPF and the shunt hybrid active power filter (SHAPF to achieve flexibility and reliability of the filter devices. Both of the two devices used the classical proportional-integral controller for pulse generation to trigger the inventers MOSFET’s. In the adopted hybrid active filter there is a passive power filter with high power rating to filter the low order harmonies and one active filter with low power rating to filter the other high order harmonies. In order to investigate the effectiveness of (SHAPF, the studies have been accomplished using simulation with the MATLAB-SIMULINK. The results show That (SHAPF is more effective than (SAPF, and has lower cost.

A Wind Farm Active Power Dispatch Strategy for Fatigue Load Reduction

DEFF Research Database (Denmark)

Zhang, Baohua; N. Soltani, Mohsen; Hu, Weihao

2016-01-01

One of the biggest challenges in wind farm management is to cope with requirements from the grid companies and to optimize efficiency and minimize wear on wind turbines. This paper addresses an optimized active power dispatch strategy of a wind farm to reduce the fatigue load of wind turbines, wh...

Comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters

Energy Technology Data Exchange (ETDEWEB)

Pettersson, S.

2009-07-01

During the past two decades, active power filters have increasingly grown their popularity as a viable method for improving electric power quality. The main reasons for this have been the advent of fast self-commutating solid-state devices, the progression of digital technology and the improved sensor technology. Four-wire active power filters provide an efficient solution for improving the quality of supply in grounded three-phase systems or three-phase systems with neutral conductors, which are commonly used for powering residential, office and public buildings. Four-wire active power filters are applicable in compensating current harmonics, reactive power, neutral current and load phase imbalance.This thesis presents a comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters. The study includes two voltage source topologies and a current source topology with two different dc-link energy storage structures, which are compared on the basis of their filtering properties, filtering performance and efficiency. The obtained results are used for determining the suitability of current source technology for four-wire active power filtering and finding the most viable four-wire shunt active power filter topology. One commonly recognized disadvantage of the current source active power filter has always been the bulky dc-link inductor. To reduce the size of the dc-link inductor, an alternative dc-link structure for current source active power filters was introduced in the late 80's. The hybrid energy storage consists of both inductive and capacitive energy storage elements, two diodes and two controllable semiconductor switching devices. Since the capacitive element is used as a main storage unit, the inductance of the dc-link inductor can be considerably reduced. However, the original dc current control method proposed is not able to utilize the full potential of the hybrid energy storage and the inductance

Non-intrusive load monitoring based on low frequency active power measurements

Directory of Open Access Journals (Sweden)

Chinthaka Dinesh

2016-03-01

Full Text Available A Non-Intrusive Load Monitoring (NILM method for residential appliances based on active power signal is presented. This method works effectively with a single active power measurement taken at a low sampling rate (1 s. The proposed method utilizes the Karhunen Loéve (KL expansion to decompose windows of active power signals into subspace components in order to construct a unique set of features, referred to as signatures, from individual and aggregated active power signals. Similar signal windows were clustered in to one group prior to feature extraction. The clustering was performed using a modified mean shift algorithm. After the feature extraction, energy levels of signal windows and power levels of subspace components were utilized to reduce the number of possible appliance combinations and their energy level combinations. Then, the turned on appliance combination and the energy contribution from individual appliances were determined through the Maximum a Posteriori (MAP estimation. Finally, the proposed method was modified to adaptively accommodate the usage patterns of appliances at each residence. The proposed NILM method was validated using data from two public databases: tracebase and reference energy disaggregation data set (REDD. The presented results demonstrate the ability of the proposed method to accurately identify and disaggregate individual energy contributions of turned on appliance combinations in real households. Furthermore, the results emphasise the importance of clustering and the integration of the usage behaviour pattern in the proposed NILM method for real households.

Site selection of active damper for stabilizing power electronics based power distribution system

DEFF Research Database (Denmark)

Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

2015-01-01

electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation......Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...

Distributed Model Predictive Control for Active Power Control of Wind Farm

DEFF Research Database (Denmark)

Zhao, Haoran; Wu, Qiuwei; Rasmussen, Claus Nygaard

2014-01-01

This paper presents the active power control of a wind farm using the Distributed Model Predictive Controller (D- MPC) via dual decomposition. Different from the conventional centralized wind farm control, multiple objectives such as power reference tracking performance and wind turbine load can...... be considered to achieve a trade-off between them. Additionally, D- MPC is based on communication among the subsystems. Through the interaction among the neighboring subsystems, the global optimization could be achieved, which significantly reduces the computation burden. It is suitable for the modern large......-scale wind farm control....

Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

Science.gov (United States)

2016-09-01

With the growing demand for a reliable electrical grid, backup power supplies and energy management systems are a necessity. Systems such as server...ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER

Reducing power consumption during execution of an application on a plurality of compute nodes

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Peters, Amanda E [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2012-06-05

Methods, apparatus, and products are disclosed for reducing power consumption during execution of an application on a plurality of compute nodes that include: executing, by each compute node, an application, the application including power consumption directives corresponding to one or more portions of the application; identifying, by each compute node, the power consumption directives included within the application during execution of the portions of the application corresponding to those identified power consumption directives; and reducing power, by each compute node, to one or more components of that compute node according to the identified power consumption directives during execution of the portions of the application corresponding to those identified power consumption directives.

New Configurations of Micro Plate-Fin Heat Sink to Reduce Coolant Pumping Power

DEFF Research Database (Denmark)

Kolaei, Alireza Rezania; Rosendahl, Lasse

2012-01-01

the optimum heat sink configuration. The particular focus of this study is to reduce the coolant mass flow rate by considering the thermal resistances of the heat sinks and, thereby, to reduce the coolant pumping power in the system. The threedimensional governing equations for the fluid flow and the heat......The thermal resistance of heat exchangers has a strong influence on the electric power produced by a thermoelectric generator (TEG). In this work, a real TEG device is applied to three configurations of micro plate-fin heat sink. The distance between certain microchannels is varied to find...... heat sink configurations reduces the coolant pumping power in the system....

A Reduced Wind Power Grid Model for Research and Education

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, V. [Energinet.dk, Fjordvejen 1-11, DK-7000 Fredericia (Denmark); Lund, T.; Hansen, A.D.; Sorensen, P.E. [Risoe National Laboratory, DK-4000 Roskilde (Denmark); Nielsen, A.H. [Centre for Electric Technology, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

2006-07-01

A reduced grid model of a transmission system with a number of central power plants, consumption centers, local wind turbines and a large offshore wind farm is developed and implemented in the simulation tool PowerFactory (DIgSILENT). The reduced grid model is given by Energinet.dk, Transmission System Operator of Denmark (TSO) for Natural Gas and Electricity, to the Danish Universities and the Risoe National Laboratory. Its intended usage is education and studying of interaction between electricity-producing wind turbines and a realistic transmission system. Focus in these studies is on voltage stability issues and on the ride-through capability of different wind turbine concepts, equipped with advanced controllers, developed by the Risoe National Laboratory.

New series active power filter for computers loads and small non-linear loads

Energy Technology Data Exchange (ETDEWEB)

Tarnini, M.Y. [Hariri Canadian Univ., Meshref (Lebanon)

2009-07-01

This paper proposed the use of a single-phase series active power filter to reduce voltage total harmonic distortion and provide improved power quality. Control schemes were developed using simple control algorithms and a reduced number of current transducers. The circuit was comprised of a power supply and zero crossing detector; a hall-effect current sensor and signal conditioning circuit; a microcontroller circuit; a driving circuit; and an inverter bridge. The filter corrected fundamental and sinusoidal voltage amplitudes. The amplitude of the fundamental current in the series filter was controlled using a microcontroller placed between the load voltage and a pre-established reference point. Experiments were conducted to test the source voltage and source current after compensation using a prototype of the filter. The control system provided effective correction of the power factor and harmonic distortion, and reached steady state in approximately 2 cycles. It was concluded that the compensator can also be adapted for use in 3-phase systems. 13 refs., 1 tab., 14 figs.

Global development of advanced nuclear power plants, and related IAEA activities

International Nuclear Information System (INIS)

2006-09-01

Renewed interest in the potential of nuclear energy to contribute to a sustainable worldwide energy mix is underlining the IAEA's statutory role in fostering the peaceful uses of nuclear energy, in particular the need for effective exchanges of information and collaborative research and technology development among Member States on advanced nuclear power technologies deployable in the near term as well as in the longer term. For applications in the medium to longer term, with rising expectations for the role of nuclear energy in the future, technological innovation has become a strong focus of nuclear power technology developments by many Member States. To meet Member States' needs, the IAEA conducts activities to foster information exchange and collaborative research and development in the area of advanced nuclear reactor technologies. These activities include coordination of collaborative research, organization of international information exchange, and analyses of globally available technical data and results, with a focus on reducing nuclear power plant capital costs and construction periods while further improving performance, safety and proliferation resistance. In other activities, evolutionary and innovative advances are catalyzed for all reactor lines such as advanced water cooled reactors, high temperature gas cooled reactors, liquid metal cooled reactors and accelerator driven systems, including small and medium sized reactors. In addition, there are activities related to other applications of nuclear energy such as seawater desalination, hydrogen production, and other process heat applications. This brochure summarizes the worldwide status and the activities related to advanced nuclear power technology development and related IAEA activities. It includes a list of the collaborative research and development projects conducted by the IAEA, as well as of the status reports and other publications produced

Power-generating process of obtaining gas-energy carrier and reducer from coal

International Nuclear Information System (INIS)

Tleugabulov, S.; Duncheva, E.; Zubkevich, M.

1999-01-01

The manufacture of power-generating gas has the important economic value for Kazakhstan having large territory, raw and fuel resources especially power coal and clean coal wastes. The technology of reception of gas-energy carrier and reducer from power coal is developed. The basic product of technological process is heated reducing gas. Reducing potential of the gas is characterized by a volumetric share of components (CO+H 2 )-RC in relation to volume of whole mix of gases received with gasification of coal. The value of parameter RC is regulated by a degree of enrichment of air by oxygen r 0 , and the temperature - by the charge of a parity of endothermic reaction in the chamber of gas regeneration. The dependence of the gas structure and temperature on the degree of enrichment of air by oxygen is shown and the circuit of the gas generator is given. (author)

A grid-voltage-sensorless resistive active power filter with series LC-filter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

Voltage-sensorless control has been investigated for Voltage Source Inverters (VSIs) for many years due to the reduced system cost and potentially improved system reliability. The VSI based Resistive Active Power Filters (R-APFs) are now widely used to prevent the harmonic resonance in power...... distribution network, for which the voltage sensors are needed in order to obtain the current reference. In this paper a grid-voltage-sensorless control strategy is proposed for the R-APF with series LC-filter. Unlike the traditional resistance emulation method, this proposed control method re...

A Grid-Voltage-Sensorless Resistive Active Power Filter with Series LC-Filter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2018-01-01

Voltage-sensorless control has been investigated for Voltage Source Inverters (VSIs) for many years due to the reduced system cost and potentially improved system reliability. The VSI based Resistive Active Power Filters (R-APFs) are now widely used to prevent the harmonic resonance in power...... distribution network, for which the voltage sensors are needed in order to obtain the current reference. In this paper a grid-voltage-sensorless control strategy is proposed for the R-APF with series LC-filter. Unlike the traditional resistance emulation method, this proposed control method re...

Air quality enhancement by reducing emissions from electric power industry

International Nuclear Information System (INIS)

Hamzeh, Ali

2006-01-01

The electric power industry is responsible for electricity generations, transmission and distribution. The system is dominated by thermal electricity generation (in Syria its share is about 80%). The fossil fuels used in te thermal power plants are a major stationary source of greenhouse gases (GHG) in addition to other pollutant. The primary GHG are CO 2 , NO x , SO 2 , CO, and VOC, of which CO 2 is believed to account for about half of the global warming. There are many approaches to reduce the amount of pollutants emitted from power systems. The best measures as given mainly by Intergovernmental Panel on Climate Change (IPCC), 1996 are presented in the paper. From the efficiency and sustainability side of view, the implementation of these approaches cannot be done optimally without an integrated environmental management program (EMP). The paper proposes an EMP as a conceptual strategy using a set of evaluation criteria to be applied on the power system on concern. As a final item, a case study of the Syrian power system is presented. The energy system in Syria emitted about 115 million tons of CO 2 in the year 2000. The electric power system alone consumes approximately 36% of the total consumed fossil fuels in the country, and is responsible of about 35-40% of the CO 2 emissions. The Syrian power system has three major problems (like many systems in the region) which need to be resolved in order to improve its operation and consequently to reduce the emission of green house gases. First, the technical electrical losses are about 25-30% of net generated electricity. Second, the power factor has reached alarming levels in various parts of the power system. Third, the efficiencies in all power plant units are very low and still decreasing rapidly. The paper gives an overview of the energy sector in Syria showing a significant potential for energy efficiency and environmental protection projects. The main outcome of the case study is a comprehensive program

Social power and approach-related neural activity

NARCIS (Netherlands)

M.A.S. Boksem (Maarten); R. Smolders (Ruud); D. de Cremer (David)

2009-01-01

textabstractIt has been argued that power activates a general tendency to approach whereas powerlessness activates a tendency to inhibit. The assumption is that elevated power involves reward-rich environments, freedom and, as a consequence, triggers an approach-related motivational orientation and

Vattenfall want to save money: will run Ringhals 3 and 4 with reduced power

International Nuclear Information System (INIS)

Anon.

1982-01-01

Ringhals 3 and 4 are nuclear power stations which require re-design before full power can be generated. To save money both stations will be running at reduced power during 1982 to generate power and gain running experience. (J.H.)

System for actively reducing sound

NARCIS (Netherlands)

Berkhoff, Arthur P.

2005-01-01

A system for actively reducing sound from a primary noise source, such as traffic noise, comprising: a loudspeaker connector for connecting to at least one loudspeaker for generating anti-sound for reducing said noisy sound; a microphone connector for connecting to at least a first microphone placed

Reduced-activation steels: present status and future development

International Nuclear Information System (INIS)

Klueh, R.L.

2007-01-01

Full text of publication follows: Reduced-activation steels for fusion reactor applications were developed in the 1980's to replace the commercial elevated- temperature steels first considered. In the United States, this involved replacing Sandvik HT9 and modified 9Cr-1Mo steels. Reduced-activation steels, which were developed for more rapid radioactivity decay following exposure in a fusion neutron environment, were patterned after the commercial steels they were to replace. The objective for the reduced-activation steels was that they have strengths (yield stress and ultimate tensile strength from room temperature to 600 deg. C) and impact toughness (measured in a Charpy test) comparable to or better than the steels they were replacing. That objective was achieved in reduced-activation steels developed in Japan, Europe, and the United States. Since the reduced-activation steels were developed in the 1980's, reactor designers have been interested designs for increased efficiency of future fusion plants. This means reactors will need to operate at higher temperatures-above 550 deg. C, which is the upper-temperature limit for the reduced-activation steels. Although the tensile and impact toughness of the reduced-activation steels exceed those of the commercial steels they were patterned after, their creep-rupture properties are inferior to some of the commercial steels they replaced. furthermore, they are much inferior to commercial steels that have been developed since the 1980's. Reasons for why the creep-rupture properties for the new commercial ferritic/martensitic steels are superior to the earlier commercial steels and the reduced-activation steels were examined. The reasons involve compositional changes that were made in the earlier commercial steels to give the new commercial steels their superior properties. Computational thermodynamics calculations were carried out to compare the expected equilibrium phases. It appears that similar changes in composition

Effectiveness of US state policies in reducing CO2 emissions from power plants

Science.gov (United States)

Grant, Don; Bergstrand, Kelly; Running, Katrina

2014-11-01

President Obama's landmark initiative to reduce the CO2 emissions of existing power plants, the nation's largest source of greenhouse gas (GHG) pollutants, depends heavily on states and their ability to devise policies that meet the goals set by the Environmental Protection Agency (EPA). Under the EPA's proposed Clean Power Plan, states will be responsible for cutting power plants' carbon pollution 30% from 2005 levels by 2030. States have already adopted several policies to reduce the electricity sector's climate impact. Some of these policies focus on reducing power plants' CO2 emissions, and others address this outcome in a more roundabout fashion by encouraging energy efficiency and renewable energy. However, it remains unclear which, if any, of these direct and indirect strategies actually mitigate plants' emissions because scholars have yet to test their effects using plant-level emission data. Here we use a newly released data source to determine whether states' policies significantly shape individual power plants' CO2 emissions. Findings reveal that certain types of direct strategy (emission caps and GHG targets) and indirect ones (public benefit funds and electric decoupling) lower plants' emissions and thus are viable building blocks of a federal climate regime.

A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

Science.gov (United States)

Bush, Craig R.

This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

Potential nanotechnology applications for reducing freshwater consumption at coal fired power plants : an early view.

Energy Technology Data Exchange (ETDEWEB)

Elcock, D. (Environmental Science Division)

2010-09-17

, if improved, would reduce energy use and concomitant water consumption. These inefficiencies include air heater inefficiencies, boiler corrosion, low operating temperatures, fuel inefficiencies, and older components that are subject to strain and failure. A variety of nanotechnology applications that could potentially be used to reduce the amount of freshwater consumed - either directly or indirectly - by these areas and activities was identified. These applications include membranes that use nanotechnology or contain nanomaterials for improved water purification and carbon capture; nano-based coatings and lubricants to insulate and reduce heat loss, inhibit corrosion, and improve fuel efficiency; nano-based catalysts and enzymes that improve fuel efficiency and improve sulfur removal efficiency; nanomaterials that can withstand high temperatures; nanofluids that have better heat transfer characteristics than water; nanosensors that can help identify strain and impact damage, detect and monitor water quality parameters, and measure mercury in flue gas; and batteries and capacitors that use nanotechnology to enable utility-scale storage. Most of these potential applications are in the research stage, and few have been deployed at coal-fired power plants. Moving from research to deployment in today's economic environment will be facilitated with federal support. Additional support for research development and deployment (RD&D) for some subset of these applications could lead to reductions in water consumption and could provide lessons learned that could be applied to future efforts. To take advantage of this situation, it is recommended that NETL pursue funding for further research, development, or deployment for one or more of the potential applications identified in this report.

Ways of reducing radiation exposure in a future nuclear power economy

International Nuclear Information System (INIS)

Morgan, K.Z.

1976-01-01

The reasons for attempting to reduce radiation exposure in a future nuclear power economy are first discussed. This is followed by a detailed examination of ways for reducing exposures. The entire fuel cycle from uranium mining through fuel reprocessing is covered but special attention is devoted to reactors, fuel and waste shipping and fuel reprocessing

Cognitive emotion regulation enhances aversive prediction error activity while reducing emotional responses.

Science.gov (United States)

Mulej Bratec, Satja; Xie, Xiyao; Schmid, Gabriele; Doll, Anselm; Schilbach, Leonhard; Zimmer, Claus; Wohlschläger, Afra; Riedl, Valentin; Sorg, Christian

2015-12-01

Cognitive emotion regulation is a powerful way of modulating emotional responses. However, despite the vital role of emotions in learning, it is unknown whether the effect of cognitive emotion regulation also extends to the modulation of learning. Computational models indicate prediction error activity, typically observed in the striatum and ventral tegmental area, as a critical neural mechanism involved in associative learning. We used model-based fMRI during aversive conditioning with and without cognitive emotion regulation to test the hypothesis that emotion regulation would affect prediction error-related neural activity in the striatum and ventral tegmental area, reflecting an emotion regulation-related modulation of learning. Our results show that cognitive emotion regulation reduced emotion-related brain activity, but increased prediction error-related activity in a network involving ventral tegmental area, hippocampus, insula and ventral striatum. While the reduction of response activity was related to behavioral measures of emotion regulation success, the enhancement of prediction error-related neural activity was related to learning performance. Furthermore, functional connectivity between the ventral tegmental area and ventrolateral prefrontal cortex, an area involved in regulation, was specifically increased during emotion regulation and likewise related to learning performance. Our data, therefore, provide first-time evidence that beyond reducing emotional responses, cognitive emotion regulation affects learning by enhancing prediction error-related activity, potentially via tegmental dopaminergic pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

Reducing Conductor Usage in Superconducting Machines by Multiple Power Supplies

DEFF Research Database (Denmark)

Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

2013-01-01

This paper presents and applies a method of reducing the needed amount of superconductor in a superconducting machine by supplying the superconductor from multiple power supplies. The method is presented and validated experimentally in a constructed prototype. Thereafter, a superconducting tape...

On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

Directory of Open Access Journals (Sweden)

Aouss Gabash

2016-02-01

Full Text Available It has recently been shown that using battery storage systems (BSSs to provide reactive power provision in a medium-voltage (MV active distribution network (ADN with embedded wind stations (WSs can lead to a huge amount of reverse power to an upstream transmission network (TN. However, unity power factors (PFs of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I, we aim to further explore the pure reactive power potential of WSs (i.e., without BSSs by investigating the issue of variable reverse power flow under different limits on PFs in an electricity market model. The main contributions of this work are summarized as follows: (1 Introducing the reactive power capability of WSs in the optimization model of the active-reactive optimal power flow (A-R-OPF and highlighting the benefits/impacts under different limits on PFs. (2 Investigating the impacts of different agreements for variable reverse power flow on the operation of an ADN under different demand scenarios. (3 Derivation of the function of reactive energy losses in the grid with an equivalent-π circuit and comparing its value with active energy losses. (4 Balancing the energy curtailment of wind generation, active-reactive energy losses in the grid and active-reactive energy import-export by a meter-based method. In Part-II, the potential of the developed model is studied through analyzing an electricity market model and a 41-bus network with different locations of WSs.

Reducing water freshwater consumption at coal-fired power plants : approaches used outside the United States.

Energy Technology Data Exchange (ETDEWEB)

Elcock, D. (Environmental Science Division)

2011-05-09

Coal-fired power plants consume huge quantities of water, and in some water-stressed areas, power plants compete with other users for limited supplies. Extensive use of coal to generate electricity is projected to continue for many years. Faced with increasing power demands and questionable future supplies, industries and governments are seeking ways to reduce freshwater consumption at coal-fired power plants. As the United States investigates various freshwater savings approaches (e.g., the use of alternative water sources), other countries are also researching and implementing approaches to address similar - and in many cases, more challenging - water supply and demand issues. Information about these non-U.S. approaches can be used to help direct near- and mid-term water-consumption research and development (R&D) activities in the United States. This report summarizes the research, development, and deployment (RD&D) status of several approaches used for reducing freshwater consumption by coal-fired power plants in other countries, many of which could be applied, or applied more aggressively, at coal-fired power plants in the United States. Information contained in this report is derived from literature and Internet searches, in some cases supplemented by communication with the researchers, authors, or equipment providers. Because there are few technical, peer-reviewed articles on this topic, much of the information in this report comes from the trade press and other non-peer-reviewed references. Reducing freshwater consumption at coal-fired power plants can occur directly or indirectly. Direct approaches are aimed specifically at reducing water consumption, and they include dry cooling, dry bottom ash handling, low-water-consuming emissions-control technologies, water metering and monitoring, reclaiming water from in-plant operations (e.g., recovery of cooling tower water for boiler makeup water, reclaiming water from flue gas desulfurization [FGD] systems), and

Active Power Regulation based on Droop for AC Microgrid

DEFF Research Database (Denmark)

Li, Chendan; Coelho, Ernane A. A.; Firoozabadi, Mehdi Savaghebi

2015-01-01

In this paper, two different control strategies are proposed to address the active power regulation issue in AC microgrids. The principle of power regulation in the droop controller is firstly introduced. Frequency scheduling and droop gain scheduling on top of droop control is proposed...... to successfully follow the active power command. The limitation of each method is discussed in term of small signal stability and light load sharing, respectively. Discussion on the effects of power command is also given. The simulation is carried out for both the strategies to verify the active power control...

Active Power Flow Optimization of Industrial Power Supply with Regard to the Transmission Line Conductor Heating

Directory of Open Access Journals (Sweden)

Leyzgold D.Yu.

2015-04-01

Full Text Available This article studies the problem of the transmission line conductor heating effect on the active power flows optimization in the local segment of industrial power supply. The purpose is to determine the optimal generation rating of the distributed power sources, in which the power flow values will correspond to the minimum active power losses in the power supply. The timeliness is the need to define the most appropriate rated power values of distributed sources which will be connected to current industrial power supply. Basing on the model of active power flow optimization, authors formulate the description of the nonlinear transportation problem considering the active power losses depending on the transmission line conductor heating. Authors proposed a new approach to the heating model parameters definition based on allowable current loads and nominal parameters of conductors as part of the optimization problem. Analysis of study results showed that, despite the relatively small active power losses reduction to the tune 0,45% due to accounting of the conductors heating effect for the present configuration of power supply, there are significant fluctuations in the required generation rating in nodes of the network to 9,32% within seasonal changes in the outer air temperature. This fact should be taken into account when selecting the optimum power of distributed generation systems, as exemplified by an arbitrary network configuration.

A review of activated carbon technologies for reducing MSW incinerator emissions

International Nuclear Information System (INIS)

Clarke, M.J.

1991-01-01

Though activated carbon is, by no means, a newcomer to the pollution control field, having been used as a water purifier and more recently demonstrated as a flue gas cleaner on power plants, it is now attracting considerable attention in Europe as a means to reduce further the quantity of toxic organic and metal emissions from new and existing municipal waste combustors. Since activated carbon is a potentially important future emissions control technology for MWCs in the US, particularly for removal of mercury and dioxin, this paper discusses the impetus which has motivated the experimentation with various activated carbon technologies which is now taking place, will describe how some of the activated carbon systems (e.g., post-emissions control fixed carbon bed and injection of carbon with scrubber reagent) being tested now function and where they fit in existing pollution control trains, and will present available performance data and emissions reductions actually achieved for each system

Modular Bayesian Networks with Low-Power Wearable Sensors for Recognizing Eating Activities

Directory of Open Access Journals (Sweden)

Kee-Hoon Kim

2017-12-01

Full Text Available Recently, recognizing a user’s daily activity using a smartphone and wearable sensors has become a popular issue. However, in contrast with the ideal definition of an experiment, there could be numerous complex activities in real life with respect to its various background and contexts: time, space, age, culture, and so on. Recognizing these complex activities with limited low-power sensors, considering the power and memory constraints of the wearable environment and the user’s obtrusiveness at once is not an easy problem, although it is very crucial for the activity recognizer to be practically useful. In this paper, we recognize activity of eating, which is one of the most typical examples of a complex activity, using only daily low-power mobile and wearable sensors. To organize the related contexts systemically, we have constructed the context model based on activity theory and the “Five W’s”, and propose a Bayesian network with 88 nodes to predict uncertain contexts probabilistically. The structure of the proposed Bayesian network is designed by a modular and tree-structured approach to reduce the time complexity and increase the scalability. To evaluate the proposed method, we collected the data with 10 different activities from 25 volunteers of various ages, occupations, and jobs, and have obtained 79.71% accuracy, which outperforms other conventional classifiers by 7.54–14.4%. Analyses of the results showed that our probabilistic approach could also give approximate results even when one of contexts or sensor values has a very heterogeneous pattern or is missing.

Modular Bayesian Networks with Low-Power Wearable Sensors for Recognizing Eating Activities.

Science.gov (United States)

Kim, Kee-Hoon; Cho, Sung-Bae

2017-12-11

Recently, recognizing a user's daily activity using a smartphone and wearable sensors has become a popular issue. However, in contrast with the ideal definition of an experiment, there could be numerous complex activities in real life with respect to its various background and contexts: time, space, age, culture, and so on. Recognizing these complex activities with limited low-power sensors, considering the power and memory constraints of the wearable environment and the user's obtrusiveness at once is not an easy problem, although it is very crucial for the activity recognizer to be practically useful. In this paper, we recognize activity of eating, which is one of the most typical examples of a complex activity, using only daily low-power mobile and wearable sensors. To organize the related contexts systemically, we have constructed the context model based on activity theory and the "Five W's", and propose a Bayesian network with 88 nodes to predict uncertain contexts probabilistically. The structure of the proposed Bayesian network is designed by a modular and tree-structured approach to reduce the time complexity and increase the scalability. To evaluate the proposed method, we collected the data with 10 different activities from 25 volunteers of various ages, occupations, and jobs, and have obtained 79.71% accuracy, which outperforms other conventional classifiers by 7.54-14.4%. Analyses of the results showed that our probabilistic approach could also give approximate results even when one of contexts or sensor values has a very heterogeneous pattern or is missing.

Modular Bayesian Networks with Low-Power Wearable Sensors for Recognizing Eating Activities

Science.gov (United States)

Kim, Kee-Hoon

2017-01-01

Recently, recognizing a user’s daily activity using a smartphone and wearable sensors has become a popular issue. However, in contrast with the ideal definition of an experiment, there could be numerous complex activities in real life with respect to its various background and contexts: time, space, age, culture, and so on. Recognizing these complex activities with limited low-power sensors, considering the power and memory constraints of the wearable environment and the user’s obtrusiveness at once is not an easy problem, although it is very crucial for the activity recognizer to be practically useful. In this paper, we recognize activity of eating, which is one of the most typical examples of a complex activity, using only daily low-power mobile and wearable sensors. To organize the related contexts systemically, we have constructed the context model based on activity theory and the “Five W’s”, and propose a Bayesian network with 88 nodes to predict uncertain contexts probabilistically. The structure of the proposed Bayesian network is designed by a modular and tree-structured approach to reduce the time complexity and increase the scalability. To evaluate the proposed method, we collected the data with 10 different activities from 25 volunteers of various ages, occupations, and jobs, and have obtained 79.71% accuracy, which outperforms other conventional classifiers by 7.54–14.4%. Analyses of the results showed that our probabilistic approach could also give approximate results even when one of contexts or sensor values has a very heterogeneous pattern or is missing. PMID:29232937

Distributed control of hybrid AC microgrids with dynamic active and reactive power capacity tuning

DEFF Research Database (Denmark)

Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

2012-01-01

Microgrids comprise of emerging generation technologies such as fuel cell, solar PV, wind turbine generator, storage and loads. They can, in principle, operate at different voltages and frequencies. Tying them either to the mains grid or among themselves would certainly require some interlinking...... power converters, whose control should preferably be done autonomously without demanding communication links. This paper proposes distributed control for power management between two Microgrids interlinked through inverters. The control scheme aims to reduce the reactive power loading stress on DERs...... and also allows active power transfer from overloaded grid to under- loaded grid. The performance of proposed control has been verified in simulation and through a scaled-down experimental system....

Coordinated Power Dispatch of a PMSG based Wind Farm for Output Power Maximizing Considering the Wake Effect and Losses

DEFF Research Database (Denmark)

Zhang, Baohua; Hu, Weihao; Hou, Peng

2016-01-01

The energy loss in a wind farm (WF) caused by wake interaction between wind turbines (WTs) is quite high, which can be reduced by proper active power dispatch. The electrical loss inside a WF by improper active power and reactive power dispatch is also considerable. In this paper, a coordinated...... active power and reactive power dispatch strategy is proposed for a Permanent magnet synchronous generator (PMSG) based WF, in order to maximize the total output power by reducing the wake effect and losses inside the devices of the WF, including the copper loss and iron loss of PMSGs, losses inside...

Energy saving and consumption reducing evaluation of thermal power plant

Science.gov (United States)

Tan, Xiu; Han, Miaomiao

2018-03-01

At present, energy saving and consumption reduction require energy saving and consumption reduction measures for thermal power plant, establishing an evaluation system for energy conservation and consumption reduction is instructive for the whole energy saving work of thermal power plant. By analysing the existing evaluation system of energy conservation and consumption reduction, this paper points out that in addition to the technical indicators of power plant, market activities should also be introduced in the evaluation of energy saving and consumption reduction in power plant. Ttherefore, a new evaluation index of energy saving and consumption reduction is set up and the example power plant is calculated in this paper. Rresults show that after introducing the new evaluation index of energy saving and consumption reduction, the energy saving effect of the power plant can be judged more comprehensively, so as to better guide the work of energy saving and consumption reduction in power plant.

Analysis and design of a parallel-connected single active bridge DC-DC converter for high-power wind farm applications

DEFF Research Database (Denmark)

Park, Kiwoo; Chen, Zhe

2013-01-01

This paper presents a parallel-connected Single Active Bridge (SAB) dc-dc converter for high-power applications. Paralleling lower-power converters can lower the current rating of each modular converter and interleaving the outputs can significantly reduce the magnitudes of input and output curre...

Evaluation of a Trapezoidal Predictive Controller for a Four-Wire Active Power Filter for Utility Equipment of Metro Railway, Power-Land Substations

Directory of Open Access Journals (Sweden)

Sergio Salas-Duarte

2016-01-01

Full Text Available The realization of an improved predictive current controller based on a trapezoidal model is described, and the impact of this technique is assessed on the performance of a 2 kW, 21.6 kHz, four-wire, Active Power Filter for utility equipment of Metro Railway, Power-Land Substations. The operation of the trapezoidal predictive current controller is contrasted with that of a typical predictive control technique, based on a single Euler approximation, which has demonstrated generation of high-quality line currents, each using a 400 V DC link to improve the power quality of an unbalanced nonlinear load of Metro Railway. The results show that the supply current waveforms become virtually sinusoidal waves, reducing the current ripple by 50% and improving its power factor from 0.8 to 0.989 when the active filter is operated with a 1.6 kW load. The principle of operation of the trapezoidal predictive controller is analysed together with a description of its practical development, showing experimental results obtained with a 2 kW prototype.

New Configurations of Micro Plate-Fin Heat Sink to Reduce Coolant Pumping Power

Science.gov (United States)

Rezania, A.; Rosendahl, L. A.

2012-06-01

The thermal resistance of heat exchangers has a strong influence on the electric power produced by a thermoelectric generator (TEG). In this work, a real TEG device is applied to three configurations of micro plate-fin heat sink. The distance between certain microchannels is varied to find the optimum heat sink configuration. The particular focus of this study is to reduce the coolant mass flow rate by considering the thermal resistances of the heat sinks and, thereby, to reduce the coolant pumping power in the system. The three-dimensional governing equations for the fluid flow and the heat transfer are solved using the finite-volume method for a wide range of pressure drop laminar flows along the heat sink. The temperature and the mass flow rate distribution in the heat sink are discussed. The results, which are in good agreement with previous computational studies, show that using suggested heat sink configurations reduces the coolant pumping power in the system.

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

DEFF Research Database (Denmark)

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

2009-01-01

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

The RED (reduce everyone's dose) initiative at Hinkley Point Power Station

International Nuclear Information System (INIS)

Weston, J.

1995-01-01

This paper does not offer a universal solution to reducing doses nor does it claim to introduce radically new ideas. It is a summarised account of the successes achieved in reducing the collective dose at a 30 year old power station. The key areas identified are the rewards of teamwork, the need to challenge established practices and the benefit of a dosimetry database. (author)

Interconverting the matrix and principal-meridional representations of dioptric power and reduced vergence.

Science.gov (United States)

Harris, W F

2000-11-01

Converting the traditional representation of power as sphere, cylinder and axis to the dioptric power matrix F is usually performed by means of Long's equations and the reverse process by means of Keating's equations. It is sometimes useful to be able to convert directly between the matrix and power expressed in terms of principal powers F1 and F2 along corresponding principal meridians at angles a1 and a2. The equations for interconverting F and the principal-meridional representation expressed as F1(a1)F2 are presented here. Equivalent equations allow direct interconversion of the reduced vergence matrix L and the principal-meridional representation of vergence L1(a1)L2. Vergence becomes infinite at line and point focuses. Similarly effective power and back- and front-vertex power are infinite for some systems. Nevertheless it is possible unambiguously to represent infinite vergence and vertex power in principal-meridional form. However, information is usually lost in these infinite cases when the principal-meridional representation is converted to the matrix representation, and the former is not recoverable from the latter. As a consequence the matrix representation is usually unsatisfactory for vergences and vertex powers that are infinite. On the other hand, the principal-meridional representation of vergence and power is always satisfactory. If one adopts the position that effective powers and vertex powers are really vergences rather than powers then one concludes that the matrix provides a satisfactory representation for powers of thin systems in general but not for vergences. Implied by a vergence at a point is an interval of Sturm. The equations for characterizing the interval from the reduced vergence are presented.

Reduced program of inspection by induced currents for condenser of Embalse nuclear power plant

International Nuclear Information System (INIS)

Obrutsky, L.; Mendonca, H.

1986-01-01

In this work it's presented a reduced inspection in service program by the technique of induced currents to the turbine condenser of Embalse's Power Plant (Cordoba). The authors based its elaboration on the results obtained in the exam of a small number of tubes and on experience obtained through four inspections in the condensers of Atucha I Power Plant, through mathematical models of oxygen and ammoniac distribution in both Power Plants, and its experimental verification in the case of Atucha I. This program improves the quality of inspection thereby reducing time, equipment and personnel employed. (C.M.) [pt

Analysis and control of a shunt active power filter

Energy Technology Data Exchange (ETDEWEB)

Ottersten, R.; Petersson, Andreas [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

1999-09-01

This report deals with active power filtering of low-frequency current harmonics. The active filter consists of a forced-commutated voltage source inverter with a digital control system. The aim of this master thesis is to investigate the performance of a shunt active power filter, and the parameters influence on the system performance. Three different harmonic identification methods are presented and compared. The shunt active power filter is very well suited for harmonic current reduction, provided that the phase shift due to the digital implementation of the control system is compensated. The performance of the active power filter depends on the switching frequency. When using individual harmonic detection methods the amount of compensation can be fully controlled for each current harmonic.

Modified Synchronous Reference Frame Based Shunt Active Power Filter with Fuzzy Logic Control Pulse Width Modulation Inverter

Directory of Open Access Journals (Sweden)

Suleiman Musa

2017-05-01

Full Text Available Harmonic distortion in power networks has greatly reduced power quality and this affects system stability. In order to mitigate this power quality issue, the shunt active power filter (SAPF has been widely applied and it is proven to be the best solution to current harmonics. This paper evaluates the performance of the modified synchronous reference frame extraction (MSRF algorithm with fuzzy logic controller (FLC based current control pulse width modulation (PWM inverter of three-phase three-wire SAPF to mitigate current harmonics. The proposed FLC is designed with a reduced amount of membership functions (MFs and rules, and thus significantly reduces the computational time and memory size. Modeling and simulations of SAPF are carried out using MATLAB/Simulink R2012a with the power system toolbox under steady-state condition, and this is followed with hardware implementation using a TMS320F28335 digital signal processor (DSP, Specrum Digital Inc., Stafford, TX, USA. The results obtained demonstrate a good and satisfactory response to mitigate the harmonics in the system. The total harmonic distortion (THD for the system has been reduced from 25.60% to 0.92% and 1.41% in the simulation study with and without FLC, respectively. Similarly for the experimental study, the SAPF can compensate for the three-phase load current by reducing THD to 5.07% and 7.4% with and without FLC, respectively.

Reducing power consumption while synchronizing a plurality of compute nodes during execution of a parallel application

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Peters, Amanda E [Cambridge, MA; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2012-04-17

Methods, apparatus, and products are disclosed for reducing power consumption while synchronizing a plurality of compute nodes during execution of a parallel application that include: beginning, by each compute node, performance of a blocking operation specified by the parallel application, each compute node beginning the blocking operation asynchronously with respect to the other compute nodes; reducing, for each compute node, power to one or more hardware components of that compute node in response to that compute node beginning the performance of the blocking operation; and restoring, for each compute node, the power to the hardware components having power reduced in response to all of the compute nodes beginning the performance of the blocking operation.

Reducing power consumption while synchronizing a plurality of compute nodes during execution of a parallel application

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Peters, Amanda A [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2012-01-10

Methods, apparatus, and products are disclosed for reducing power consumption while synchronizing a plurality of compute nodes during execution of a parallel application that include: beginning, by each compute node, performance of a blocking operation specified by the parallel application, each compute node beginning the blocking operation asynchronously with respect to the other compute nodes; reducing, for each compute node, power to one or more hardware components of that compute node in response to that compute node beginning the performance of the blocking operation; and restoring, for each compute node, the power to the hardware components having power reduced in response to all of the compute nodes beginning the performance of the blocking operation.

Active Snubber Circuit for High Power Inverter Leg

DEFF Research Database (Denmark)

Rasmussen, Tonny Wederberg; Johansen, Morten Holst

2009-01-01

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

A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

2016-01-01

Passive trap filters are widely used in high power Voltage Source Inverters (VSI) for the switching harmonic attenuation. The usage of the passive trap filters requires clustered and fixed switching harmonic spectrum, which is not the case for low pulse-ratio or Variable Switching Frequency (VSF...... current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...

A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

Energy Technology Data Exchange (ETDEWEB)

Wang, Ruxi [Virginia Polytechnic Institute and State University (Virginia Tech); Wang, Fei [ORNL; Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech); Burgos, Rolando [ABB; Lai, Rixin [General Electric; Ning, Puqi [ORNL; Rajashekara, Kaushik [Rolls Royce

2011-01-01

It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemes is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.

Meditation leads to reduced default mode network activity beyond an active task.

Science.gov (United States)

Garrison, Kathleen A; Zeffiro, Thomas A; Scheinost, Dustin; Constable, R Todd; Brewer, Judson A

2015-09-01

Meditation has been associated with relatively reduced activity in the default mode network, a brain network implicated in self-related thinking and mind wandering. However, previous imaging studies have typically compared meditation to rest, despite other studies having reported differences in brain activation patterns between meditators and controls at rest. Moreover, rest is associated with a range of brain activation patterns across individuals that has only recently begun to be better characterized. Therefore, in this study we compared meditation to another active cognitive task, both to replicate the findings that meditation is associated with relatively reduced default mode network activity and to extend these findings by testing whether default mode activity was reduced during meditation, beyond the typical reductions observed during effortful tasks. In addition, prior studies had used small groups, whereas in the present study we tested these hypotheses in a larger group. The results indicated that meditation is associated with reduced activations in the default mode network, relative to an active task, for meditators as compared to controls. Regions of the default mode network showing a Group × Task interaction included the posterior cingulate/precuneus and anterior cingulate cortex. These findings replicate and extend prior work indicating that the suppression of default mode processing may represent a central neural process in long-term meditation, and they suggest that meditation leads to relatively reduced default mode processing beyond that observed during another active cognitive task.

The determinants of intermediaries’ power over farmers’ margin-related activities

DEFF Research Database (Denmark)

Xhoxhi, Orjon; Pedersen, Søren Marcus; Lind, Kim Martin Hjorth

2014-01-01

This paper investigates the determinants of intermediaries’ power over farmers’ margin-related activities in Adana, Turkey. In doing so, a holistic model of intermediaries’ power over farmers’ margin-related activities is proposed. The objective of this model is to contribute to a better understa......This paper investigates the determinants of intermediaries’ power over farmers’ margin-related activities in Adana, Turkey. In doing so, a holistic model of intermediaries’ power over farmers’ margin-related activities is proposed. The objective of this model is to contribute to a better...

Grid-Connected Photovoltaic System with Active Power Filtering Functionality

Directory of Open Access Journals (Sweden)

Joaquín Vaquero

2018-01-01

Full Text Available Solar panels are an attractive and growing source of renewable energy in commercial and residential applications. Its use connected to the grid by means of a power converter results in a grid-connected photovoltaic system. In order to optimize this system, it is interesting to integrate several functionalities into the power converter, such as active power filtering and power factor correction. Nonlinear loads connected to the grid generate current harmonics, which deteriorates the mains power quality. Active power filters can compensate these current harmonics. A photovoltaic system with added harmonic compensation and power factor correction capabilities is proposed in this paper. A sliding mode controller is employed to control the power converter, implemented on the CompactRIO digital platform from National Instruments Corporation, allowing user friendly operation and easy tuning. The power system consists of two stages, a DC/DC boost converter and a single-phase inverter, and it is able to inject active power into the grid while compensating the current harmonics generated by nonlinear loads at the point of common coupling. The operation, design, simulation, and experimental results for the proposed system are discussed.

Design of power control system using SMES and SVC for fusion power plant

International Nuclear Information System (INIS)

Niiyama, K; Yagai, T; Tsuda, M; Hamajima, T

2008-01-01

A SMES (Superconducting Magnetic Energy Storage System) system with converter composed of self-commutated valve devices such as GTO and IGBT is available to control active and reactive power simultaneously. A SVC (Static Var Compensators) or STATCOM (Static Synchronous Compensator) is widely employed to reduce reactive power in power plants and substations. Owing to progress of power electronics technology using GTO and IGBT devices, power converters in the SMES system and the SVC can easily control power flow in few milliseconds. Moreover, since the valve devices for the SMES are equivalent to those for the SVC, the device cost must be reduced. In this paper the basic control system combined with the SMES and SVC is designed for large pulsed loads of a nuclear fusion power plant. This combined system largely expands the reactive power control region as well as the active one. The simulation results show that the combined system is effective and prospective for the nuclear fusion power plant

Usefulness of DC power flow for active power flow analysis with flow controlling devices

NARCIS (Netherlands)

Van Hertem, D.; Verboomen, J.; Purchala, K.; Belmans, R.; Kling, W.L.

2006-01-01

DC power flow is a commonly used tool for contingency analysis. Recently, due to its simplicity and robustness, it also becomes increasingly used for the real-time dispatch and techno-economic analysis of power systems. It is a simplification of a full power flow looking only at active power.

Short-term strategies for Dutch wind power producers to reduce imbalance costs

International Nuclear Information System (INIS)

Chaves-Ávila, José Pablo; Hakvoort, Rudi A.; Ramos, Andrés

2013-01-01

The paper assesses bidding strategies for a wind power producer in the Netherlands. To this end, a three-stage stochastic optimization framework is used, maximizing wind power producer's profit using the day-ahead and cross-border intraday market, taking into account available interconnection capacity. Results show that the wind power producer can increase its profits by trading on the intraday market and – under certain imbalance prices – by intentionally creating imbalances. It has been considered uncertainties about prices, power forecast and interconnection capacity at the day-ahead and intraday timeframes. - Highlights: ► A cross-border bidding strategy model for wind power producers has been developed. ► The model was applied to a real case study of a Dutch offshore wind power producer. ► Under certain imbalance prices, it is not profitable to deliver all possible power. ► Intraday markets give the possibility to reduce imbalance costs. ► Integration of intraday markets will increase liquidity.

Maximum wind power plant generation by reducing the wake effect

International Nuclear Information System (INIS)

De-Prada-Gil, Mikel; Alías, César Guillén; Gomis-Bellmunt, Oriol; Sumper, Andreas

2015-01-01

Highlights: • To analyze the benefit of applying a new control strategy to maximise energy yield. • To operate some wind turbines at non-optimum points for reducing wake effects. • Single, partial and multiple wakes for any wind direction are taken into account. • Thrust coefficient is computed according to Blade Element Momentum (BEM) theory. - Abstract: This paper analyses, from a steady state point of view, the potential benefit of a Wind Power Plant (WPP) control strategy whose main objective is to maximise its total energy yield over its lifetime by taking into consideration that the wake effect within the WPP varies depending on the operation of each wind turbine. Unlike the conventional approach in which each wind turbine operation is optimised individually to maximise its own energy capture, the proposed control strategy aims to optimise the whole system by operating some wind turbines at sub-optimum points, so that the wake effect within the WPP is reduced and therefore the total power generation is maximised. The methodology used to assess the performance of both control approaches is presented and applied to two particular study cases. It contains a comprehensive wake model considering single, partial and multiple wake effects among turbines. The study also takes into account the Blade Element Momentum (BEM) theory to accurately compute both power and thrust coefficient of each wind turbine. The results suggest a good potential of the proposed concept, since an increase in the annual energy captured by the WPP from 1.86% up to 6.24% may be achieved (depending on the wind rose at the WPP location) by operating some specific wind turbines slightly away from their optimum point and reducing thus the wake effect

Shunt hybrid active power filter for harmonic mitigation: A practical ...

Indian Academy of Sciences (India)

The increasing importance of Power Quality problems has been responsible for several improvements in Active Power Filter (APF) typologies in the last decade. The increased cost and switching losses make a pure shunt APF economically impractical for high power applications. In higher power levels shunt Hybrid Active ...

Power module assembly with reduced inductance

Energy Technology Data Exchange (ETDEWEB)

Ward, Terence G.; Stancu, Constantin C.; Jaksic, Marko; Mann, Brooks S.

2018-03-13

A power module assembly has a plurality of electrically conducting layers, including a first layer and a third layer. One or more electrically insulating layers are operatively connected to each of the plurality of electrically conducting layers. The electrically insulating layers include a second layer positioned between and configured to electrically isolate the first and the third layers. The first layer is configured to carry a first current flowing in a first direction. The third layer is configured to carry a second current flowing in a second direction opposite to the first direction, thereby reducing an inductance of the assembly. The electrically insulating layers may include a fourth layer positioned between and configured to electrically isolate the third layer and a fifth layer. The assembly results in a combined substrate and heat sink structure. The assembly eliminates the requirements for connections between separate substrate and heat sink structures.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

Science.gov (United States)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Soft Power in Central Asia: Actors and Its Activities

Directory of Open Access Journals (Sweden)

Marina M. Lebedeva

2014-01-01

Full Text Available Article considers theoretical aspects of soft power concept and its use by various actors in Central Asia. It is noted that scholars as well as practitioners are paying insufficient attention to such key concepts position J. Nye, as an attraction. As a result the efficiency of the use of soft power is significantly reduced. It also shows that the attractiveness is not a universal characteristic. For this reason, attractiveness and hence soft power of different actors are different and aimed at different segments of the population. These differences lead to competition of actors, but they do not reduce interaction in the region to zero-sum game. Specific forms and directions of the soft power of Russia, the U.S., the EU and China in Central Asia are discussed. The article emphasizes that the Central Asian states are not just recipients of soft power of external actors, but also themselves form behavioral strategies that are attractive to others.

A Reduced Switch Voltage Stress Class E Power Amplifier Using Harmonic Control Network

OpenAIRE

Ali Reza Zirak; Sobhan Roshani

2016-01-01

In this paper, a harmonic control network (HCN) is presented to reduce the voltage stress (maximum MOSFET voltage) of the class E power amplifier (PA). Effects of the HCN on the amplifier specifications are investigated. The results show that the proposed HCN affects several specifications of the amplifier, such as drain voltage, switch current, output power capability (Cp factor), and drain impedance. The output power capability of the presented amplifier is also improved, compared with the ...

Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement

Science.gov (United States)

Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G.

2017-10-01

A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor.

Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, F.L.; Moraes, A.J.; Guimaraes, G.C.; Sanhueza, S.M.R.; Vaz, A.R. [Federal University of Uberlandia (UFU), MG (Brazil)

2009-07-01

In the case of photovoltaic solar systems (PV) acting as a distributed generation (DG), the DC energy obtained is fed through the power-conditioning unit (inverter) to the grid. The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can be utilized instead of CSI, we can generate reactive power commensurate with the remaining unused capacity at any given point in time. According to the theory of instantaneous power, the reactive and active power of inverter can be regulated by changing the amplitude and the phase of the output voltage of the inverter. Based on this theory, the active power output and the reactive power compensation (RPC) of the system are realized simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of PV system can still be used to improve the utilization factor of the inverter. The MATLAB simulation results validate the feasibility of the method. (author)

Phytochemical characterization, antimicrobial activity and reducing potential of seed oil, latex, machine oil and presscake of Jatropha curcas.

Science.gov (United States)

Sharma, Amit Kumar; Gangwar, Mayank; Kumar, Dharmendra; Nath, Gopal; Kumar Sinha, Akhoury Sudhir; Tripathi, Yamini Bhushan

2016-01-01

This study aims to evaluate the antimicrobial activity, phytochemical studies and thin layer chromatography analysis of machine oil, hexane extract of seed oil and methanol extract of presscake & latex of Jatropha curcas Linn (family Euphorbiaceae). J. curcas extracts were subjected to preliminary qualitative phytochemical screening to detect the major phytochemicals followed by its reducing power and content of phenol and flavonoids in different fractions. Thin layer chromatography was also performed using different solvent systems for the analysis of a number of constituents in the plant extracts. Antimicrobial activity was evaluated by the disc diffusion method, while the minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration were calculated by micro dilution method. The methanolic fraction of latex and cake exhibited marked antifungal and antibacterial activities against Gram-positive and Gram-negative bacteria. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, terpenoids, steroids, glycosides, phenols and flavonoids. Reducing power showed dose dependent increase in concentration compared to standard Quercetin. Furthermore, this study recommended the isolation and separation of bioactive compounds responsible for the antibacterial activity which would be done by using different chromatographic methods such as high-performance liquid chromatography (HPLC), GC-MS etc. The results of the above study suggest that all parts of the plants possess potent antibacterial activity. Hence, it is important to isolate the active principles for further testing of antimicrobial and other biological efficacy.

Unconventional power - a factor of reducing the pollution in Romania

International Nuclear Information System (INIS)

Terzi, P.

1996-01-01

The unconventional power generation includes all the activities related to the utilization and management of energy sources, facilities and equipment used to produce and distribute the power obtained through systems other than those based on burning of classical fissile fuels. By its very nature it is not pollutant. The renewable energies as the solar, wind, geothermal, tidal energies, etc, enter this category. As in the same category it is included the energy recovered from different industrial processes, usually associated with the treatment of organic residues or of refuse waters, the unconventional power generation is an important factor in ecological and environmental policy. The paper stresses also the beneficial accompanying actions which are associated with exploiting other unconventional energy sources. For instance, the tidal power exploitation implies also measures of protection of see shore regions from erosion and other forms of decay

Studies on total polyphenols and reducing power of aqueous extracts from selected lamiaceae species

Directory of Open Access Journals (Sweden)

Maria Cioroi

2010-08-01

Full Text Available Certain phytochemicals in species are attracting increased attention because of a wide range of biological activities especially the possible cancer preventive properties. Polyphenols, the naturalantioxidants are present in plant extracts and they play a key role in antioxidative defence mechanisms in biological systems and they act as free radicals scavenging agents. Polyphenols might thereforeinhibit development of coronary heart disease and cancers. Basil, oregano and sage are highly fragrant plants whose leaves are used as a seasoning herb for many different types of foods. Aqueous extractswere prepared from basil (Ocimum basilicum L., oregano (Origanum vulgare L. and sage (Salvia officinalis L.. To check the phenols presence, the UV-VIS spectrum was made. The amount of polyphenolic compounds from selected Lamiaceae species was determined by spectrophotometry method using the Folin - Ciocalteau reagent and gallic acid as standard. The range of polyphenols total was between 516,352 mg/100g dried species and 859,617 mg/100g dried species.Reducing power has been established by measuring the redox potential of aqueous extracts. Antioxidant activity was directly correlated with the total amount of polyphenols in the species extracts.The free reducing sugars in aqueous extracts from species were analyzed and correlated to the total content of polyphenols.

Effect of radiation on activity of sulphate reducing bacteria

International Nuclear Information System (INIS)

Agaev, N.M.; Smorodin, A.E.; Gusejnov, M.M.

1985-01-01

The effect of γ-radiation on activity of sulphate reducing bacteria has been studied. Concentration of biogenic hydrogen, generated in the medium, is the main criterion, characterizing corrosion activity of the bacteria studied. The developed method of suppression of active development of sulfate reducing bacteria considerably reduces, and at lethal doses of γ-radiation eliminates altogether the bacteria activity and formation of the main corrosion agent-hydrogen sulphide-in the medium and that, in its turn, liquidates hydrogen sulphide corrosion

Design and control of hybrid active power filters

CERN Document Server

Lam, Chi-Seng

2014-01-01

Design and Control of Hybrid Active Power Filters presents an overview of the current quality problems and their compensators. To get a balance between the system cost and performance, hybrid active power filters (HAPFs) are valuable. The book presents the coverage of resonance phenomena prevention capability, filtering performance and system robustness analysis of HAPF; nonlinear inverter current slope characteristics and their linear operation region requirement analysis of the hysteresis PWM for the HAPF; minimum inverter capacity design procedure of HAPF, adaptive dc-link voltage controller for the HAPF and the real design example of a 220V 10kVA HAPF, in which the system performance analysis method, minimum dc voltage deduction concept and adaptive dc voltage idea can be further extended into the other active compensators, such as APF, static synchronous compensator STATCOM, etc. This book will benefit researchers, graduate students, and electrical power engineers in the field of power-quality compensati...

THE PHASE REACTOR INDUCTANCE SELECTION TECHNIQUE FOR POWER ACTIVE FILTER

Directory of Open Access Journals (Sweden)

D. V. Tugay

2016-12-01

Full Text Available Purpose. The goal is to develop technique of the phase inductance power reactors selection for parallel active filter based on the account both low-frequency and high-frequency components of the electromagnetic processes in a power circuit. Methodology. We have applied concepts of the electrical circuits theory, vector analysis, mathematical simulation in Matlab package. Results. We have developed a new technique of the phase reactors inductance selection for parallel power active filter. It allows us to obtain the smallest possible value of THD network current. Originality. We have increased accuracy of methods of the phase reactor inductance selection for power active filter. Practical value. The proposed technique can be used in the design and manufacture of the active power filter for real objects of energy supply.

Actions taken in order to reduce doses to workers in PWR power plants

International Nuclear Information System (INIS)

Jeanson, P.

1978-01-01

The dose limitation for workers in nuclear power plants is a permanent aim of Electricite de France. Many ways are followed at the same time to reach it, some of them in collaboration with C.E.A. Theoretical studies concern mostly sources and transfers of corrosion and fission products in the primary circuit of pressurized water reactors as well as the means for reducing the deposited activity. Practical studies concern design problems for equipment and buildings. They try to specify rules for these purposes. They also concern maintenance conditions of all components: for the most important components, special tools are designed. At last, studies and experimentation of daily dosimetry should bring a better knowledge of the distribution of collective doses and, subsequently, should give a better idea of the actions to be undertaken [fr

Hybrid Active Filter with Variable Conductance for Harmonic Resonance Suppression in Industrial Power Systems

DEFF Research Database (Denmark)

Lee, Tzung-Lin; Wang, Yen-Ching; Li, Jian-Cheng

2015-01-01

Unintentional series and/or parallel resonances, due to the tuned passive filter and the line inductance, may result in severe harmonic distortion in the industrial power system. This paper presents a hybrid active filter to suppress harmonic resonance and reduce harmonic distortion as well...... expensive. A reasonable trade-off between filtering performances and cost is to use the hybrid active filter. Design consideration are presented and experimental results are provided to validate effectiveness of the proposed method. Furthermore, this paper discusses filtering performances on line impedance...

Assessments and applications to enhance human reliability and reduce risk during less-than-full-power operations

International Nuclear Information System (INIS)

Hannaman, G.W.; Singh, A.

1992-01-01

Study of events, interviews with plant personnel, and applications of risk studies indicate that the risk of a potential accident during less-than-full-power (LTFP) operation is becoming a greater fraction of the risk as improvements are made to the full-power operations. Industry efforts have been increased to reduce risk and the cost of shutdown operations. These efforts consider the development and application of advanced tools to help utilities proactively identify issues and develop contingencies and interventions to enhance reliability and reduce risk of low-power operations at nuclear power plants. The role for human reliability assessments is to help improve utility outage planning to better achieve schedule and risk control objectives. Improvements are expected to include intervention tools to identify and reduce human error, definition of new instructional modules, and prioritization of risk reduction issues for operators. The Electric Power Research Institute is sponsoring a project to address the identification and quantification of factors that affect human reliability during LTFP operation of nuclear power plants. The results of this project are expected to promote the development of proactively applied interventions and contingencies for enhanced human reliability during shutdown operations

Reduced order models inertial manifold and global bifurcations: searching instability boundaries in nuclear power systems

International Nuclear Information System (INIS)

Suarez Antola, R.

2009-01-01

In the framework of an analytic or numerical model of a BWR power plant, this could imply first to find an suitable approximation to the solution manifold of the differential equations describing the stability behaviour of this nonlinear system, and then a classification of the different solution types concerning their relation with the operational safety of the power plant, by distributing the different solution types in relation with the exclusion region of the power-flow map. Then the goal is to obtain the best attainable qualitative and quantitative global picture of plant dynamics. To do this, the construction and the analysis of the so called reduced order models (Rom) seems a necessary step. A reduced order model results after the full system of coupled nonlinear partial differential equations of the plant is reduced to a system of coupled nonlinear ordinary differential equations

Will nuclear power plant standardization reduce the licensing impact on construction

International Nuclear Information System (INIS)

Allen, J.M.; Bingham, W.G.; Keith, D.G.

1976-01-01

The NRC and the nuclear industry have been pursuing standardization quite vigorously in an effort to reduce the cost and schedule for the design and construction of nuclear power plants. The NRC is currently reviewing standard plant applications submitted under each of four standardization options. In addition, the NRC has published Standard Review Plans and Standard Technical Specifications. Although problems exist in the implementation of standardization and in areas unaffected by standardization, each of these standardization methods has the potential to reduce the licensing impact on construction

DSP control of photovoltaic power generation system adding the function of shunt active power filter

Energy Technology Data Exchange (ETDEWEB)

Seo, H.-R.; Kim, K.-H.; Park, Y.-G.; Park, M.; Yu, I.-K. [Changwon National Univ., SarimDong (Korea, Republic of). Dept. of Electrical Engineering

2007-07-01

The growing number of power electronics-based equipment has created a problem on the quality of electric power supply since both high power industrial loads and domestic loads cause harmonics in the network voltage. Power quality problems can occur in the system or can be caused by the consumer. Active filter (AF) is widely used to compensate current harmonics and/or current imbalance of harmonic-producing loads. The power output of a photovoltaic (PV) system is directly affected by weather conditions. When alternating current (AC) power supply is required, power conversion by an inverter and an MPPT control is necessary. The proliferation of nonlinear loads such as inverter of PV power generation system can be treated as a harmonic source for the power distribution system. As such, the PV system combined with the function of the active filter system can be useful for the application in power distribution systems. This paper described a PV-AF system using DSP to prove that it is possible to combine AF theory to the three phase PV system connected to utility and verify it through experimental results. The paper described the control method of the PV-AF system, with reference to the photovoltaic power generation system, shunt active filter and PV-AF system. The experimental set-up was also presented. A laboratory system was designed and constructed to confirm the viability of the proposed PV-AF system. The test results revealed the stability and effectiveness of the proposed PV-AF system. 12 refs., 1 tabs., 12 figs.

Recreational Activities to Reduce Behavioural Symptoms in Dementia

Science.gov (United States)

Kolanowski, Ann; Fick, Donna M.; Buettner, Linda

2009-01-01

Few clinicians have an educational grounding in the use of nonpharmacological therapies for people with dementia. In this article, we explore the utility of recreational activities as one nonpharmacological intervention that has demonstrated effectiveness for reducing the behavioural symptoms of dementia. The implementation of effective recreational activities involves three components: understanding the evidence for this approach; acknowledging the need to reduce medications that have the potential to interfere with activity effectiveness; and individualizing activities so that the maximum benefit from the intervention is obtained. PMID:20046903

Sox11 Reduces Caspase-6 Cleavage and Activity.

Directory of Open Access Journals (Sweden)

Elaine Waldron-Roby

Full Text Available The apoptotic cascade is an orchestrated event, whose final stages are mediated by effector caspases. Regulatory binding proteins have been identified for caspases such as caspase-3, -7, -8, and -9. Many of these proteins belong to the inhibitor of apoptosis (IAP family. By contrast, caspase-6 is not believed to be influenced by IAPs, and little is known about its regulation. We therefore performed a yeast-two-hybrid screen using a constitutively inactive form of caspase-6 for bait in order to identify novel regulators of caspase-6 activity. Sox11 was identified as a potential caspase-6 interacting protein. Sox11 was capable of dramatically reducing caspase-6 activity, as well as preventing caspase-6 self- cleavage. Several regions, including amino acids 117-214 and 362-395 within sox11 as well as a nuclear localization signal (NLS all contributed to the reduction in caspase-6 activity. Furthermore, sox11 was also capable of decreasing other effector caspase activity but not initiator caspases -8 and -9. The ability of sox11 to reduce effector caspase activity was also reflected in its capacity to reduce cell death following toxic insult. Interestingly, other sox proteins also had the ability to reduce caspase-6 activity but to a lesser extent than sox11.

Active Power Measurement Based on Multiwavelet Transforms

Directory of Open Access Journals (Sweden)

Xiao-Bing Zhang

2014-01-01

Full Text Available This paper discusses a new method for calculating active power in the multiwavelet domain. When the voltage and current waveforms are analyzed using multiwavelet, the active power can be calculated by simply adding the products of the multiwavelet coefficients without having to reconstruct the signals back to the time domain first and then using the traditional integration. From the simulation result, we can see that the results using multiwavelet are better than the ones using wavelet and Fourier Transforms no matter which prefilter is used.

The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury

Directory of Open Access Journals (Sweden)

Domingo Antoinette

2006-02-01

Full Text Available Abstract Background Powered lower limb orthoses could reduce therapist labor during gait rehabilitation after neurological injury. However, it is not clear how patients respond to powered assistance during stepping. Patients might allow the orthoses to drive the movement pattern and reduce their muscle activation. The goal of this study was to test the effects of robotic assistance in subjects with incomplete spinal cord injury using pneumatically powered ankle-foot orthoses. Methods Five individuals with chronic incomplete spinal cord injury (ASIA C-D participated in the study. Each subject was fitted with bilateral ankle-foot orthoses equipped with artificial pneumatic muscles to power ankle plantar flexion. Subjects walked on a treadmill with partial bodyweight support at four speeds (0.36, 0.54, 0.72 and 0.89 m/s under three conditions: without wearing orthoses, wearing orthoses unpowered (passively, and wearing orthoses activated under pushbutton control by a physical therapist. Subjects also attempted a fourth condition wearing orthoses activated under pushbutton control by them. We measured joint angles, electromyography, and orthoses torque assistance. Results A therapist quickly learned to activate the artificial pneumatic muscles using the pushbuttons with the appropriate amplitude and timing. The powered orthoses provided ~50% of peak ankle torque. Ankle angle at stance push-off increased when subjects walked with powered orthoses versus when they walked with passive-orthoses (ANOVA, p Two of the five subjects were able to control the orthoses themselves using the pushbuttons. The other three subjects found it too difficult to coordinate pushbutton timing. Orthoses assistance and maximum ankle angle at push-off were smaller when the subject controlled the orthoses compared to when the therapist-controlled the orthoses (p Conclusion Mechanical assistance from powered ankle-foot orthoses improved ankle push-off kinematics without

Reduced Voltage Scaling in Clock Distribution Networks

Directory of Open Access Journals (Sweden)

Khader Mohammad

2009-01-01

Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

A simple approach to calculate active power of electrosurgical units

Directory of Open Access Journals (Sweden)

André Luiz Regis Monteiro

Full Text Available Abstract Introduction: Despite of more than a hundred years of electrosurgery, only a few electrosurgical equipment manufacturers have developed methods to regulate the active power delivered to the patient, usually around an arbitrary setpoint. In fact, no manufacturer has a method to measure the active power actually delivered to the load. Measuring the delivered power and computing it fast enough so as to avoid injury to the organic tissue is challenging. If voltage and current signals can be sampled in time and discretized in the frequency domain, a simple and very fast multiplication process can be used to determine the active power. Methods This paper presents an approach for measuring active power at the output power stage of electrosurgical units with mathematical shortcuts based on a simple multiplication procedure of discretized variables – frequency domain vectors – obtained through Discrete Fourier Transform (DFT applied on time-sampled voltage and current vectors. Results Comparative results between simulations and a practical experiment are presented – all being in accordance with the requirements of the applicable industry standards. Conclusion An analysis is presented comparing the active power analytically obtained through well-known voltage and current signals against a computational methodology based on vector manipulation using DFT only for time-to-frequency domain transformation. The greatest advantage of this method is to determine the active power of noisy and phased out signals with neither complex DFT or ordinary transform methodologies nor sophisticated computing techniques such as convolution. All results presented errors substantially lower than the thresholds defined by the applicable standards.

The economics of reducing CO2 emissions by solar thermal power plants

International Nuclear Information System (INIS)

Brakmann, G.

1993-01-01

The necessity to reduce CO 2 -emissions on a global scale is being recognized by scientists and politicians. If no scientific proof of a climate catastrophe due to CO 2 -emissions can be established, it would nevertheless be prudent to implement a form of global survival insurance policy, the premium of which is the required effort to reduce CO 2 -emissions. The implementation of such a policy without a considerable reduction in the living standard requires the replacement of fossil fuels by capital and/or know-how. It should be performed in the most economical manner. This leads to the replacement of the classical ''least cost power expansion strategy'' by the ''least cost power expansion/pollution limiting strategy''. Thereby projects have to compete no longer exclusively on low cost of energy production but on low cost of pollution reduction as well. (Author)

Phytochemical characterization, antimicrobial activity and reducing potential of seed oil, latex, machine oil and presscake of Jatropha curcas

Directory of Open Access Journals (Sweden)

Amit Sharma

2016-06-01

Full Text Available Objective: This study aims to evaluate the antimicrobial activity, phytochemical studies and thin layer chromatography analysis of machine oil, hexane extract of seed oil and methanol extract of presscake& latex of Jatropha curcas Linn (family Euphorbiaceae. Materials and Methods: J. curcas extracts were subjected to preliminary qualitative phytochemical screening to detect the major phytochemicals followed by its reducing power and content of phenol and flavonoids in different fractions. Thin layer chromatography was also performed using different solvent systems for the analysis of a number of constituents in the plant extracts. Antimicrobial activity was evaluated by the disc diffusion method, while the minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration were calculated by micro dilution method. Results: The methanolic fraction of latex and cake exhibited marked antifungal and antibacterial activities against Gram-positive and Gram-negative bacteria. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, terpenoids, steroids, glycosides, phenols and flavonoids. Reducing power showed dose dependent increase in concentration compared to standard Quercetin. Furthermore, this study recommended the isolation and separation of bioactive compounds responsible for the antibacterial activity which would be done by using different chromatographic methods such as high-performance liquid chromatography (HPLC, GC-MS etc. Conclusion: The results of the above study suggest that all parts of the plants possess potent antibacterial activity. Hence, it is important to isolate the active principles for further testing of antimicrobial and other biological efficacy.

Rapid Active Power Control of Photovoltaic Systems for Grid Frequency Support

Energy Technology Data Exchange (ETDEWEB)

Hoke, Anderson; Shirazi, Mariko; Chakraborty, Sudipta; Muljadi, Eduard; Maksimovic, Dragan

2017-01-01

As deployment of power electronic coupled generation such as photovoltaic (PV) systems increases, grid operators have shown increasing interest in calling on inverter-coupled generation to help mitigate frequency contingency events by rapidly surging active power into the grid. When responding to contingency events, the faster the active power is provided, the more effective it may be for arresting the frequency event. This paper proposes a predictive PV inverter control method for very fast and accurate control of active power. This rapid active power control method will increase the effectiveness of various higher-level controls designed to mitigate grid frequency contingency events, including fast power-frequency droop, inertia emulation, and fast frequency response, without the need for energy storage. The rapid active power control method, coupled with a maximum power point estimation method, is implemented in a prototype PV inverter connected to a PV array. The prototype inverter's response to various frequency events is experimentally confirmed to be fast (beginning within 2 line cycles and completing within 4.5 line cycles of a severe test event) and accurate (below 2% steady-state error).

Low cost concepts to reduce the voltage ripple of the DC power supply

International Nuclear Information System (INIS)

Cheng, Y.; Liu, K.B.

1993-01-01

If the gain of current feedback is low, the short term stability of magnet power supply will be affected by a soft power line. Typically, the step-charge and the imbalance of the three phase power line cause the most serious voltage ripple. Usually, the voltage feedback with a coupling transformer is considered to reduce the voltage ripple. However, for the high current power supply, the space and cooling problem of the coupling transformer become inconvenient. In this paper, the authors suggest to use the toroidal core with the compensation winding, working like a DCCT, as the coupling transformer. Then, a high speed detector of the AC line level is developed. It restricts the voltage ripple passing to the coupling transformer. These methods have the advantage of small size, low power consumption and low cost

Line Capacity Expansion and Transmission Switching in Power Systems With Large-Scale Wind Power

DEFF Research Database (Denmark)

Villumsen, Jonas Christoffer; Bronmo, Geir; Philpott, Andy B.

2013-01-01

In 2020 electricity production from wind power should constitute nearly 50% of electricity demand in Denmark. In this paper we look at optimal expansion of the transmission network in order to integrate 50% wind power in the system, while minimizing total fixed investment cost and expected cost...... of power generation. We allow for active switching of transmission elements to reduce congestion effects caused by Kirchhoff's voltage law. Results show that actively switching transmission lines may yield a better utilization of transmission networks with large-scale wind power and increase wind power...

Cooperative Control of Active Power Filters in Power Systems without Mutual Communication

Czech Academy of Sciences Publication Activity Database

Tlustý, J.; Škramlík, Jiří; Švec, J.; Valouch, Viktor

2010-01-01

Roč. 2010, č. 517184 (2010), s. 1-13 ISSN 1024-123X R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : active power filter * power system * wireless cooperation Subject RIV: JA - Electronics ; Optoelectronics, Electric al Engineering Impact factor: 0.689, year: 2010 http://www.hindawi.com/journals/mpe/2010/517184.html

EVALUATING DEGREE OF ACTIVE POWER LOSSES REDUCTION IN THE ELECTRIC POWER LINES WITH REACTIVE POWER COMPENSATION

Directory of Open Access Journals (Sweden)

V. N. Radkevich

2016-01-01

Full Text Available The paper considers evaluation procedure for the degree of active power losses reduction in the power transmission lines under 1 kV and 6–10 kV of the systems of electric power supply of industrial enterprises with compensating installations mounted at the side of the customer. The capacitor installations conform to the applied voltage level and factor in dielectric losses in the capacitors. The voltage at the compensating device terminal changes from 0.95 to 1.05 of the capacitors nominal voltage. The study did not account for reactive power losses in the line, nor did it for its charge capacity, conditioned by relative shortness of the cable lines generally operating in the mains of industrial enterprises. For this reason, the quantities of reactive power being consumed and generated by the transmission line are negligible and do not significantly affect the reactive power flux. The researchers obtain functional relations that allow estimating the degree of power loss reduction in the transmission line factoring in its explicit initial data. They perform mathematical analysis of the obtained functional relations and study the function by means of derivatives. The function extremum points are found as well as the intervals of its increment and decrement. A graphical research of the obtained functional relation is performed. It is ascertained that reduction of the active power losses is contingent on the line and the capacitor-installation engineering factors, the electrical energy consumer reactive load value as well as the voltage applied to the capacitor installation. The functional relations presented in the article can be employed in scoping calculation necessary for decision making on the reactive power compensation in systems of the industrial facilities electric power supply. Their account will allow a more accurate estimate of technical and economic effect of the capacitor bank installation in the electrical mains under 1 kV and 6�

Active Vibration Control for Helicopter Interior Noise Reduction Using Power Minimization

Science.gov (United States)

Mendoza, J.; Chevva, K.; Sun, F.; Blanc, A.; Kim, S. B.

2014-01-01

This report describes work performed by United Technologies Research Center (UTRC) for NASA Langley Research Center (LaRC) under Contract NNL11AA06C. The objective of this program is to develop technology to reduce helicopter interior noise resulting from multiple gear meshing frequencies. A novel active vibration control approach called Minimum Actuation Power (MAP) is developed. MAP is an optimal control strategy that minimizes the total input power into a structure by monitoring and varying the input power of controlling sources. MAP control was implemented without explicit knowledge of the phasing and magnitude of the excitation sources by driving the real part of the input power from the controlling sources to zero. It is shown that this occurs when the total mechanical input power from the excitation and controlling sources is a minimum. MAP theory is developed for multiple excitation sources with arbitrary relative phasing for single or multiple discrete frequencies and controlled by a single or multiple controlling sources. Simulations and experimental results demonstrate the feasibility of MAP for structural vibration reduction of a realistic rotorcraft interior structure. MAP control resulted in significant average global vibration reduction of a single frequency and multiple frequency excitations with one controlling actuator. Simulations also demonstrate the potential effectiveness of the observed vibration reductions on interior radiated noise.

Feedback Linearization Control of a Shunt Active Power Filter Using a Fuzzy Controller

Directory of Open Access Journals (Sweden)

Tianhua Li

2013-09-01

Full Text Available In this paper, a novel feedback linearization based sliding mode controlled parallel active power filter using a fuzzy controller is presented in a three-phase three-wire grid. A feedback linearization control with fuzzy parameter self-tuning is used to implement the DC side voltage regulation while a novel integral sliding mode controller is applied to reduce the total harmonic distortion of the supply current. Since traditional unit synchronous sinusoidal signal calculation methods are not applicable when the supply voltage contains harmonics, a novel unit synchronous sinusoidal signal computing method based on synchronous frame transforming theory is presented to overcome this disadvantage. The simulation results verify that the DC side voltage is very stable for the given value and responds quickly to the external disturbance. A comparison is also made to show the advantages of the novel unit sinusoidal signal calculating method and the super harmonic treatment property of the designed active power filter.

Approach to reducing the effect of bone—coal power station on radiation environment

Institute of Scientific and Technical Information of China (English)

NIShi－Ying; GUPei－Long; 等

2002-01-01

The effect of two bone-coal power stations(6MWe) on environment was investigated within the scope of the dose contribution caused by various radionucildes in different ways.It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder(BCC),soot and ash in the catchers.

Approach to reducing the effect of bone-coal power station on radiation environment

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

The effect of two bone-coal power stations (6 MWe) on environment wasinvestigated within the scope of the dose contribution caused by various radionucildes in different ways. It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder (BCC), soot and ash in the catchers.

Ultra-supercritical (USC) technology. The best practical and economic way to reduce CO{sub 2} emissions from coal fired power plants

Energy Technology Data Exchange (ETDEWEB)

Mao, Jianxiong [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering

2013-07-01

China is the largest coal producer and consumer with largest coal power capacity in the world. By the end of 2010, the total installed power capacity in China was 962,190 MWe, in which coal fired power capacity was 706,630 MWe, accounting for over 73.4%. China has been the largest CO{sub 2} emission country as well and its huge coal power capacity is the largest CO{sub 2} emission source. How does China reduce its CO{sub 2} emissions from coal fired power plants is an austere challenge now we are facing. How does China reduce its CO{sub 2} emissions from coal fired power plants? There are three ways to reduce CO{sub 2} emissions from coal fired power plants: (1) carbon capture and storage (CCS); (2) co-firing biomass with coal; (3) much improvement of efficiency. For the first option of CCS, the technology is still under development and there are still several uncertainties today to be widely used for coal fired power plants in the short term. For the second option of biomass co-firing, it can reduce CO{sub 2} emissions in a way, but it is difficult to implement it in China without strong support of incentive policy. Therefore, the third option of improvement of efficiency is the only but also the best and feasible economic option for China to much reduce CO{sub 2} emissions from coal fired power plants. This paper will discuss how China to take a active policy to strongly promote the application of supercritical (SC)/Ultra supercritical (USC) technology. Only in 4 years from 2007 to 2010, ordered capacity of coal fired SC/USC units was 482 units with installed capacity of 230,060 MWe, in which, 1,000 MWe USC with 600 C steam parameters was almost 100 units with 100,000 MWe in which 33 units have been in operation. Today, China has been a country with the largest SC/USC units and capacity. The fast application of SC/USC units for coal fired power plants has resulted in energy saving and reduction of emissions. The average coal consumption in China reduced from 366

Power system stabilising features from wind power plants augmented with energy storage

DEFF Research Database (Denmark)

Tarnowski, Germán C.; Kjær, Philip C; Lærke, Rasmus

2014-01-01

This paper describes a wind power plant augmented with energy storage, configured to provide ancillary services (primary reserve, inertial response, power oscillation damping) for enhancement of power system stability. Energy storage can complement wind power plants thus reducing the need for any...... overload or curtailment to allow active power modulation. A 12MW + 1.6MW augmented plant is used for demonstration of representative performance of the particular ancillary service control algorithms...

Performance of an Active Micro Direct Methanol Fuel Cell Using Reduced Catalyst Loading MEAs

Directory of Open Access Journals (Sweden)

D.S. Falcão

2017-10-01

Full Text Available The micro direct methanol fuel cell (MicroDMFC is an emergent technology due to its special interest for portable applications. This work presents the results of a set of experiments conducted at room temperature using an active metallic MicroDMFC with an active area of 2.25 cm2. The MicroDMFC uses available commercial materials with low platinum content in order to reduce the overall fuel cell cost. The main goal of this work is to provide useful information to easily design an active MicroDMFC with a good performance recurring to cheaper commercial Membrane Electrode Assemblies MEAs. A performance/cost analysis for each MEA tested is provided. The maximum power output obtained was 18.1 mW/cm2 for a hot-pressed MEA with materials purchased from Quintech with very low catalyst loading (3 mg/cm2 Pt–Ru at anode side and 0.5 mg/cm2 PtB at the cathode side costing around 15 euros. Similar power values are reported in literature for the same type of micro fuel cells working at higher operating temperatures and substantially higher cathode catalyst loadings. Experimental studies using metallic active micro direct methanol fuel cells operating at room temperature are very scarce. The results presented in this work are, therefore, very useful for the scientific community.

Analysis and experimental evaluation of shunt active power filter for power quality improvement based on predictive direct power control.

Science.gov (United States)

Aissa, Oualid; Moulahoum, Samir; Colak, Ilhami; Babes, Badreddine; Kabache, Nadir

2017-10-12

This paper discusses the use of the concept of classical and predictive direct power control for shunt active power filter function. These strategies are used to improve the active power filter performance by compensation of the reactive power and the elimination of the harmonic currents drawn by non-linear loads. A theoretical analysis followed by a simulation using MATLAB/Simulink software for the studied techniques has been established. Moreover, two test benches have been carried out using the dSPACE card 1104 for the classic and predictive DPC control to evaluate the studied methods in real time. Obtained results are presented and compared in this paper to confirm the superiority of the predictive technique. To overcome the pollution problems caused by the consumption of fossil fuels, renewable energies are the alternatives recommended to ensure green energy. In the same context, the tested predictive filter can easily be supplied by a renewable energy source that will give its impact to enhance the power quality.

Distribution grid reconfiguration reduces power losses and helps integrate renewables

International Nuclear Information System (INIS)

Lueken, Colleen; Carvalho, Pedro M.S.; Apt, Jay

2012-01-01

A reconfigurable network can change its topology by opening and closing switches on power lines. We use real wind, solar, load, and cost data and a model of a reconfigurable distribution grid to show that reconfiguration allows a grid operator to reduce operational losses as well as to accept more intermittent renewable generation than a static configuration can. Net present value analysis of automated switch technology shows that the return on investment is negative for this test network when considering only loss reduction, but that the investment is attractive under certain conditions when reconfiguration is used to minimize curtailment. - Highlights: ► Reconfiguration may reduce losses in grids with solar or wind distributed generation. ► Reconfigurable networks can accept more solar or wind DG than static ones. ► Using reconfiguration for loss reduction would not create a positive ROI. ► Using reconfiguration to reduce curtailment usually would create a positive ROI.

Modular hot swappable 50 V, 700 A DC power supply with active redundancy

International Nuclear Information System (INIS)

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

2015-01-01

A 50 V, 700 A voltage regulated modular hot swappable DC power supply has been designed and developed to bias 32 numbers of 500 W, 505.8 MHz solid state RF amplifiers for Indus-2 RF system. This power supply employs 7 numbers of 50 V, 100 A power modules which are operated in parallel and share load current equally. Active redundancy with hot swappable features incorporated in this power supply isolates the faulty module and facilitates its online replacement without affecting the operation of RF amplifiers, thereby significantly reducing the down time of the overall system. Each power module has inbuilt harmonics and power factor correction stage to improve its input performance parameters. This power supply has a dedicated controller, which monitors the healthiness of 32 numbers of RF amplifiers and 7 numbers of power modules, controls the equal sharing of load current among these modules as well as isolates the faulty RF amplifiers and power modules. The control system allows the user to set the trip limits for bias current of individual RF amplifier, power module currents and total power supply current independently for effective protection of the overall system. Issues related to EMI and high frequency switching noises are suitably taken care of in this power supply. The crucial parameters of this power supply are displayed on a local LCD panel as well as on remote PC via ethernet communication. This paper compares the availability and reliability of this hot swappable power supply with the configuration involving one dedicated power supply for each RF amplifier. The performance parameters of this power supply tested with solid state RF amplifiers are also presented in this paper. (author)

Balancing computation and communication power in power constrained clusters

Science.gov (United States)

Piga, Leonardo; Paul, Indrani; Huang, Wei

2018-05-29

Systems, apparatuses, and methods for balancing computation and communication power in power constrained environments. A data processing cluster with a plurality of compute nodes may perform parallel processing of a workload in a power constrained environment. Nodes that finish tasks early may be power-gated based on one or more conditions. In some scenarios, a node may predict a wait duration and go into a reduced power consumption state if the wait duration is predicted to be greater than a threshold. The power saved by power-gating one or more nodes may be reassigned for use by other nodes. A cluster agent may be configured to reassign the unused power to the active nodes to expedite workload processing.

Active and reactive power neurocontroller for grid-connected photovoltaic generation system

Directory of Open Access Journals (Sweden)

I. Abadlia

2016-03-01

Full Text Available Many researchers have contributed to the development of a firm foundation for analysis and design of control applications in grid-connected renewable energy sources. This paper presents an intelligent control algorithm fond on artificial neural networks for active and reactive power controller in grid-connected photovoltaic generation system. The system is devices into two parts in which each part contains an inverter with control algorithm. A DC/DC converter in output voltage established by control magnitude besides maximum power point tracker algorithm always finds optimal power of the PV array in use. A DC/AC hysteresis inverter designed can synchronize a sinusoidal current output with the grid voltage and accurate an independent active and reactive power control. Simulation results confirm the validation of the purpose. Neurocontroller based active and reactive power presents an efficiency control that guarantees good response to the steps changing in active and reactive power with an acceptable current/voltage synchronism. In this paper the power circuit and the control system of the presented grid-connected photovoltaic generation system is simulated and tested by MatLab/Simulink.

Sustainable Modular Adaptive Redundancy Technique Emphasizing Partial Reconfiguration for Reduced Power Consumption

Directory of Open Access Journals (Sweden)

R. Al-Haddad

2011-01-01

Full Text Available As reconfigurable devices' capacities and the complexity of applications that use them increase, the need for self-reliance of deployed systems becomes increasingly prominent. Organic computing paradigms have been proposed for fault-tolerant systems because they promote behaviors that allow complex digital systems to adapt and survive in demanding environments. In this paper, we develop a sustainable modular adaptive redundancy technique (SMART composed of a two-layered organic system. The hardware layer is implemented on a Xilinx Virtex-4 Field Programmable Gate Array (FPGA to provide self-repair using a novel approach called reconfigurable adaptive redundancy system (RARS. The software layer supervises the organic activities on the FPGA and extends the self-healing capabilities through application-independent, intrinsic, and evolutionary repair techniques that leverage the benefits of dynamic partial reconfiguration (PR. SMART was evaluated using a Sobel edge-detection application and was shown to tolerate stressful sequences of injected transient and permanent faults while reducing dynamic power consumption by 30% compared to conventional triple modular redundancy (TMR techniques, with nominal impact on the fault-tolerance capabilities. Moreover, PR is employed to keep the system on line while under repair and also to reduce repair time. Experiments have shown a 27.48% decrease in repair time when PR is employed compared to the full bitstream configuration case.

Low activation material design methodology for reduction of radio-active wastes of nuclear power plant

International Nuclear Information System (INIS)

Hasegawa, A.; Satou, M.; Nogami, S.; Kakinuma, N.; Kinno, M.; Hayashi, K.

2007-01-01

Most of the concrete shielding walls and pipes around a reactor pressure vessel of a light water reactor become low level radioactive waste at decommission phase because they contain radioactive nuclides by thermal-neutron irradiation during its operation. The radioactivity of some low level radioactive wastes is close to the clearance level. It is very desirable in terms of life cycle cost reduction that the radioactivity of those low level radioactive wastes is decreased below clearance level. In case of light water reactors, however, methodology of low activation design of a nuclear plant has not been established yet because the reactor is a large-scale facility and has various structural materials. The Objectives of this work are to develop low activation material design methodology and material fabrication for reduction of radio-active wastes of nuclear power plant such as reinforced concrete. To realize fabrication of reduced radioactive concrete, it is necessary to develop (1) the database of the chemical composition of raw materials to select low activation materials, (2) the tool for calculation of the neutron flux and the spectrum distribution of nuclear plants to evaluate radioactivity of reactor components, (3) optimization of material process conditions to produce the low activation cement and the low activation steels. Results of the data base development, calculation tools and trial production of low activation cements will be presented. (authors)

Reducing power consumption while performing collective operations on a plurality of compute nodes

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Peters, Amanda E [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2011-10-18

Methods, apparatus, and products are disclosed for reducing power consumption while performing collective operations on a plurality of compute nodes that include: receiving, by each compute node, instructions to perform a type of collective operation; selecting, by each compute node from a plurality of collective operations for the collective operation type, a particular collective operation in dependence upon power consumption characteristics for each of the plurality of collective operations; and executing, by each compute node, the selected collective operation.

Active filter for INDUS-2 Q4 and Q5 power supplies

International Nuclear Information System (INIS)

Singh, Y.P.; Thakurta, A.C.; Kotaiah, S.

2003-01-01

Q4 and Q5 power supplies are SCR based power supplies wherein the rectified voltage is fed to a passive filter to reduce the ripple voltage. The output of the passive filter still contains some ripple particularly on the low frequency side. Attenuation of this ripple with passive filter necessitates increase in size of L and C and leads to sluggishness of the system. The design and the test results of an active filter module have been discussed wherein the low frequency attenuation can be very effectively taken care of by, allowing this to be absorbed in a coupling transformer put after the passive filter. Considerable size reduction has been achieved by using switching techniques. Low frequency attenuation has been made quite a simple task. This filter also helps in handling transients from input. (author)

D.C. side active filter for high stability accelerator magnet power supplies

International Nuclear Information System (INIS)

Singh, Yash Pal; Thakurta, A.C.; Kotaiah, S.

2006-01-01

Accelerator d.c, magnets have to produce a highly stable magnetic field which in turn needs highly stable d.c. current sources to energise them. Indus-II Q4 and Q5 power supplies are SCR based power supplies wherein the rectified voltage is fed to a passive filter to reduce the ripple voltage. The output of the passive filter still contains some ripple particularly on the low frequency side. The design and the test results of an active filter module have been discussed wherein the low frequency attenuation can be very effectively taken care of by allowing this to be absorbed in a coupling transformer put after the passive filter. Considerable size reduction has been achieved by using switching techniques. Low frequency attenuation has been made quite a simple task. This filter also helps in handling transients from input. (author)

Voting Power and Shareholder Activism

DEFF Research Database (Denmark)

Strand, Therese; Poulsen, Thomas; Thomsen, Steen

2010-01-01

The article discusses the development of a voting power theory that is applied to a unique data set on Swedish shareholder meetings. The authors hypothesize that there is a positive relationship between shareholder activism and the largest shareholder's sensitivity to greater participation by small...... shareholders. It is shown that firms' amenability to small shareholder influence results in more proposals by nomination committees that are dominated by large shareholders, but fewer proposals by other shareholders. The importance of local institutions are highlighted and a call for more research regarding...... shareholder activism in alternative institutional settings is mad...

Aircraft panel with sensorless active sound power reduction capabilities through virtual mechanical impedances

Science.gov (United States)

Boulandet, R.; Michau, M.; Micheau, P.; Berry, A.

2016-01-01

This paper deals with an active structural acoustic control approach to reduce the transmission of tonal noise in aircraft cabins. The focus is on the practical implementation of the virtual mechanical impedances method by using sensoriactuators instead of conventional control units composed of separate sensors and actuators. The experimental setup includes two sensoriactuators developed from the electrodynamic inertial exciter and distributed over an aircraft trim panel which is subject to a time-harmonic diffuse sound field. The target mechanical impedances are first defined by solving a linear optimization problem from sound power measurements before being applied to the test panel using a complex envelope controller. Measured data are compared to results obtained with sensor-actuator pairs consisting of an accelerometer and an inertial exciter, particularly as regards sound power reduction. It is shown that the two types of control unit provide similar performance, and that here virtual impedance control stands apart from conventional active damping. In particular, it is clear from this study that extra vibrational energy must be provided by the actuators for optimal sound power reduction, mainly due to the high structural damping in the aircraft trim panel. Concluding remarks on the benefits of using these electrodynamic sensoriactuators to control tonal disturbances are also provided.

Application of Hybrid HS and Tabu Search Algorithm for Optimal Location of FACTS Devices to Reduce Power Losses in Power Systems

Directory of Open Access Journals (Sweden)

Z. Masomi Zohrabad

2016-12-01

Full Text Available Power networks continue to grow following the annual growth of energy demand. As constructing new energy generation facilities bears a high cost, minimizing power grid losses becomes essential to permit low cost energy transmission in larger distances and additional areas. This study aims to model an optimization problem for an IEEE 30-bus power grid using a Tabu search algorithm based on an improved hybrid Harmony Search (HS method to reduce overall grid losses. The proposed algorithm is applied to find the best location for the installation of a Unified Power Flow Controller (UPFC. The results obtained from installation of the UPFC in the grid are presented by displaying outputs.

Model based active power control of a wind turbine

DEFF Research Database (Denmark)

Mirzaei, Mahmood; Soltani, Mohsen; Poulsen, Niels Kjølstad

2014-01-01

in the electricity market that selling the reserve power is more profitable than producing with the full capacity. Therefore wind turbines can be down-regulated and sell the differential capacity as the reserve power. In this paper we suggest a model based approach to control wind turbines for active power reference...

Development of low-activation design method for reduction of radioactive waste (2). Precise neutron flux and activation estimation of nuclear power plants using MATXSLIB-J33T10

International Nuclear Information System (INIS)

Uematsu, Mikio; Hayashi, Katsumi; Nemezawa, Shigeki; Ogata, Tomohiro; Nakata, Mikihiro; Kinno, Masaharu; Yamaguchi, Katsuyoshi; Saito, Minoru; Hasegawa, Akira

2008-01-01

We have been developing low-activation concrete for biological shielding wall of nuclear power plants, for the purpose of reducing large amount of radioactive waste. Based on measurement of Eu and Co content in various aggregate candidates, limestone and electro-fused alumina were selected as the most feasible aggregate for low activation concrete. Induced activity in shielding wall was calculated for both low activation concrete and ordinary concrete using neutron flux obtained from DORT two-dimensional calculation made for typical ABWR and APWR models. We have prepared new cross section library named 'MATXSLIB-J33T10 that has multi-group structure in thermal energy. The library was processed from evaluated cross section library JENDL 3.3 by using NJOY 99.83. Activation cross section library for ORIGEN-79 code is prepared for each activation calculation case by collapsing JENDL-3.3 originated 183-group constants into 3-group activation cross section using 183-group neutron flux. One-group activation cross section was also prepared in the same manner for ORIGEN2 calculation. The ΣD/C value results for low-activation concrete was sufficiently low comparing to the ordinary concrete. By using the developed low-activation concrete, activation level of biological shielding wall concrete will be effectively decreased. The use of the developed low-activation concrete will contribute to economization of nuclear power plants decommissioning by reducing large amount of radioactive concrete waste. (author)

Wind power integration into the automatic generation control of power systems with large-scale wind power

Directory of Open Access Journals (Sweden)

Abdul Basit

2014-10-01

Full Text Available Transmission system operators have an increased interest in the active participation of wind power plants (WPP in the power balance control of power systems with large wind power penetration. The emphasis in this study is on the integration of WPPs into the automatic generation control (AGC of the power system. The present paper proposes a coordinated control strategy for the AGC between combined heat and power plants (CHPs and WPPs to enhance the security and the reliability of a power system operation in the case of a large wind power penetration. The proposed strategy, described and exemplified for the future Danish power system, takes the hour-ahead regulating power plan for generation and power exchange with neighbouring power systems into account. The performance of the proposed strategy for coordinated secondary control is assessed and discussed by means of simulations for different possible future scenarios, when wind power production in the power system is high and conventional production from CHPs is at a minimum level. The investigation results of the proposed control strategy have shown that the WPPs can actively help the AGC, and reduce the real-time power imbalance in the power system, by down regulating their production when CHPs are unable to provide the required response.

Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

Energy Technology Data Exchange (ETDEWEB)

Chinthavali, Madhu Sudhan [ORNL; Onar, Omer C [ORNL; Miller, John M [ORNL; Tang, Lixin [ORNL

2013-01-01

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

Shunt hybrid active power filter for harmonic mitigation: A practical ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... The increasing importance of Power Quality problems has been responsible for several improvements in Active Power Filter (APF) typologies in the last decade. The increased cost and switching losses make a pure shunt APF economically impractical for high power applications. In higher power levels ...

Three phase active power filter with selective harmonics elimination

Directory of Open Access Journals (Sweden)

Sozański Krzysztof

2016-03-01

Full Text Available This paper describes a three phase shunt active power filter with selective harmonics elimination. The control algorithm is based on a digital filter bank. The moving Discrete Fourier Transformation is used as an analysis filter bank. The correctness of the algorithm has been verified by simulation and experimental research. The paper includes exemplary results of current waveforms and their spectra from a three phase active power filter.

Power requirements reducing of FBG based all-optical switching

Science.gov (United States)

Scholtz, Ľubomír.; Solanská, Michaela; Ladányi, Libor; Müllerová, Jarmila

2017-12-01

Although Fiber Bragg gratings (FBGs) are well known devices, their using as all-optical switching elements has been still examined. Current research is focused on optimization of their properties for their using in future all-optical networks. The main problem are high switching intensities needed for achieving the changes of the transmission state. Over several years switching intensities have been reduced from hundreds of GW/cm2 to tens of MW/cm2 by selecting appropriate gratings and signal parameters or using suitable materials. Two principal nonlinear effects with similar power requirements can result in the bistable transmission/reflection of an input optical pulse. In the self-phase modulation (SPM) regime switching is achieved by the intense probe pulse itself. Using cross-phase modulation (XPM) a strong pump alters the FBG refractive index experienced by a weak probe pulse. As a result of this the detuning of the probe pulse from the center of the photonic band gap occurs. Using of XPM the effect of modulation instability is reduced. Modulation instability which is the main SPM degradation mechanism. We focused on nonlinear FBGs based on chalcogenide glasses which are very often used in various applications. Thanks to high nonlinear parameters chalcogenide glasses are suitable candidates for reducing switching intensities of nonlinear FBGs.

Flicker Mitigation by Active Power Control of Variable-Speed Wind Turbines With Full-Scale Back-to-Back Power Converters

DEFF Research Database (Denmark)

Hu, Weihao; Chen, Zhe; Wang, Zhaoan

2009-01-01

/EMTDC. Flicker emission of this system is investigated. Reactive power compensation is mostly adopted for flicker mitigation. However, the flicker mitigation technique shows its limits, when the grid impedance angle is low in some distribution networks. A new method of flicker mitigation by controlling active...... power is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the dc-link voltage of the full-scale converter. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation controller...... is an effective means for flicker mitigation of variable-speed wind turbines with full-scale back-to-back power converters during continuous operation....

Activating Attachments Reduces Memories of Traumatic Images.

Directory of Open Access Journals (Sweden)

Richard A Bryant

Full Text Available Emotional memories, and especially intrusive memories, are a common feature of many psychological disorders, and are overconsolidated by stress. Attachment theory posits that activation of mental representations of attachment figures can reduce stress and boost coping. This study tested the proposition that attachment activation would reduce consolidation of emotional and intrusive memories. Sixty-seven undergraduate students viewed subliminal presentations of traumatic and neutral images, which were preceded by subliminal presentations of either attachment-related images or non-attachment-related images; free recall and intrusive memories were assessed two days later. Participants with low avoidant attachment tendencies who received the attachment primes recalled fewer memories and reported fewer intrusions than those who received the non-attachment primes. Unexpectedly, those with high anxious attachment tendencies reported fewer memories. These findings generally accord with attachment theory, and suggest that consolidation of emotional memories can be moderated by activation of attachment representations.

Adaptive Fuzzy Control for Power-Frequency Characteristic Regulation in High-RES Power Systems

Directory of Open Access Journals (Sweden)

Evangelos Rikos

2017-07-01

Full Text Available Future power systems control will require large-scale activation of reserves at distribution level. Despite their high potential, distributed energy resources (DER used for frequency control pose challenges due to unpredictability, grid bottlenecks, etc. To deal with these issues, this study presents a novel strategy of power frequency characteristic dynamic adjustment based on the imbalance state. This way, the concerned operators become aware of the imbalance location but also a more accurate redistribution of responsibilities in terms of reserves activations is achieved. The proposed control is based on the concept of “cells” which are power systems with operating capabilities and responsibilities similar to control areas (CAs, but fostering the use of resources at all voltage levels, particularly distribution grids. Control autonomy of cells allows increased RES hosting. In this study, the power frequency characteristic of a cell is adjusted in real time by means of a fuzzy controller, which curtails part of the reserves, in order to avoid unnecessary deployment throughout a synchronous area, leading to a more localised activation and reducing losses, congestions and reserves exhaustion. Simulation tests in a four-cell reference power system prove that the controller significantly reduces the use of reserves without compromising the overall stability.

Balancing modern Power System with large scale of wind power

DEFF Research Database (Denmark)

Basit, Abdul; Altin, Müfit; Hansen, Anca Daniela

2014-01-01

Power system operators must ensure robust, secure and reliable power system operation even with a large scale integration of wind power. Electricity generated from the intermittent wind in large propor-tion may impact on the control of power system balance and thus deviations in the power system...... frequency in small or islanded power systems or tie line power flows in interconnected power systems. Therefore, the large scale integration of wind power into the power system strongly concerns the secure and stable grid operation. To ensure the stable power system operation, the evolving power system has...... to be analysed with improved analytical tools and techniques. This paper proposes techniques for the active power balance control in future power systems with the large scale wind power integration, where power balancing model provides the hour-ahead dispatch plan with reduced planning horizon and the real time...

Gamma power is phase-locked to posterior alpha activity.

Directory of Open Access Journals (Sweden)

Daria Osipova

Full Text Available Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30-70 Hz is phase-locked to alpha oscillations (8-13 Hz in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs reflects a window of excitability.

History of measures taken to reduce radiation exposure at Hamaoka Nuclear Power Station

International Nuclear Information System (INIS)

Kondou, Masashi; Takagi, Nobuyuki; Yabushita, Kazuo; Dekijima, Makoto

2009-01-01

Hamaoka Nuclear Power Station currently has five reactors, Units 1 to 5. Units 1 and 2 halted commercial operation in January 2009 and are now being prepared for decommissioning. Units 3 to 5 are operating at the rated thermal output with the gross electrical output of 3504 MWe. Hamaoka Nuclear Power Station has been operating for about 30 years since Unit 1 started up in 1976. Various measures have been taken to control water chemistry: for controlling SCC in the core internals and structural materials, hydrogen injection and noble metal injection were implemented; and to reduce radiation exposure for workers, condensate filter demineralizers were added, hollow fiber filters and pleated filters were installed in the condensate cleanup system, and zinc injection was performed. This paper describes measures taken at Hamaoka to reduce exposure in terms of water chemistry and techniques to monitor ion impurities in the reactor water. (author)

Active power control strategies for inverter-based distributed power generation adapted to grid-fault ride-through requirements

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

2009-01-01

Distributed power generation is expected to deliver power into the grid without interruption during voltage dips. To improve system ride-through capabilities, a generalized active power control strategy is proposed for grid-interfacing inverters. Specifically, a current reference generation strategy

Micro-supercapacitors based on interdigital electrodes of reduced graphene oxide and carbon nanotube composites with ultrahigh power handling performance

Energy Technology Data Exchange (ETDEWEB)

Beidaghi, Majid; Wang, Chunlei [Department of Mechanical and Materials Engineering, Florida International University, 10555 W. Flagler St., EC 3463, FL 33174 (United States)

2012-11-07

A novel method for fabricating micro-patterned interdigitated electrodes based on reduced graphene oxide (rGO) and carbon nanotube (CNT) composites for ultra-high power handling micro-supercapacitor application is reported. The binder-free microelectrodes were developed by combining electrostatic spray deposition (ESD) and photolithography lift-off methods. Without typically used thermal or chemical reduction, GO sheets are readily reduced to rGO during the ESD deposition. Electrochemical measurements show that the in-plane interdigital design of the microelectrodes is effective in increasing accessibility of electrolyte ions in-between stacked rGO sheets through an electro-activation process. Addition of CNTs results in reduced restacking of rGO sheets and improved energy and power density. Cyclic voltammetry (CV) measurements show that the specific capacitance of the micro-supercapacitor based on rGO-CNT composites is 6.1 mF cm{sup -2} at 0.01 V s{sup -1}. At a very high scan rate of 50 V s{sup -1}, a specific capacitance of 2.8 mF cm{sup -2} (stack capacitance of 3.1 F cm{sup -3}) is recorded, which is an unprecedented performance for supercapacitors. The addition of CNT, electrolyte-accessible and binder-free microelectrodes, as well as an interdigitated in-plane design result in a high-frequency response of the micro-supercapacitors with resistive-capacitive time constants as low as 4.8 ms. These characteristics suggest that interdigitated rGO-CNT composite electrodes are promising for on-chip energy storage application with high power demands. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The management plan preparation activities nuclear power plant in Indonesia

International Nuclear Information System (INIS)

Utomo

2011-01-01

A feasibility Study that has been updated show that two nuclear power units with each unit of power up to 1000 MWe can represent decently an economical alternative energy supply. It added that the available time schedule was quite tight so that the preparation for the development must be starting first. This paper will discuss the preparation of plans of the first nuclear power plant which includes program activities, the structure of contracts, schedules of activities and funding. From the information obtained to date that in addition to a candidate site that is ready to be built in Muria peninsula is still required another potential alternative site besides to search other complete data information. This site investigation activities completed within the time schedule was passed ''critical path'', so that these activities should be carried out intensively and obey the time. This paper describes the steps that need to be prepared to welcome the first nuclear power plant, after reviewing the various input above and apply the reality in Indonesia as the initial conditions. (author)

Shape-Dependent Activity of Ceria for Hydrogen Electro-Oxidation in Reduced-Temperature Solid Oxide Fuel Cells.

Science.gov (United States)

Tong, Xiaofeng; Luo, Ting; Meng, Xie; Wu, Hao; Li, Junliang; Liu, Xuejiao; Ji, Xiaona; Wang, Jianqiang; Chen, Chusheng; Zhan, Zhongliang

2015-11-04

Single crystalline ceria nanooctahedra, nanocubes, and nanorods are hydrothermally synthesized, colloidally impregnated into the porous La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) scaffolds, and electrochemically evaluated as the anode catalysts for reduced temperature solid oxide fuel cells (SOFCs). Well-defined surface terminations are confirmed by the high-resolution transmission electron microscopy--(111) for nanooctahedra, (100) for nanocubes, and both (110) and (100) for nanorods. Temperature-programmed reduction in H2 shows the highest reducibility for nanorods, followed sequentially by nanocubes and nanooctahedra. Measurements of the anode polarization resistances and the fuel cell power densities reveal different orders of activity of ceria nanocrystals at high and low temperatures for hydrogen electro-oxidation, i.e., nanorods > nanocubes > nanooctahedra at T ≤ 450 °C and nanooctahedra > nanorods > nanocubes at T ≥ 500 °C. Such shape-dependent activities of these ceria nanocrystals have been correlated to their difference in the local structure distortions and thus in the reducibility. These findings will open up a new strategy for design of advanced catalysts for reduced-temperature SOFCs by elaborately engineering the shape of nanocrystals and thus selectively exposing the crystal facets. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Active Power Control of Waked Wind Farms: Preprint

Energy Technology Data Exchange (ETDEWEB)

Fleming, Paul A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); van Wingerden, Jan-Willem [Delft University of Technology; Pao, Lucy [University of Colorado; Aho, Jacob [University of Colorado

2017-08-15

Active power control can be used to balance the total power generated by wind farms with the power consumed on the electricity grid. With the increasing penetration levels of wind energy, there is an increasing need for this ancillary service. In this paper, we show that the tracking of a certain power reference signal provided by the transmission system operator can be significantly improved by using feedback control at the wind farm level. We propose a simple feedback control law that significantly improves the tracking behavior of the total power output of the farm, resulting in higher performance scores. The effectiveness of the proposed feedback controller is demonstrated using high-fidelity computational fluid dynamics simulations of a small wind farm.

Systematic review of active workplace interventions to reduce sickness absence.

Science.gov (United States)

Odeen, M; Magnussen, L H; Maeland, S; Larun, L; Eriksen, H R; Tveito, T H

2013-01-01

The workplace is used as a setting for interventions to prevent and reduce sickness absence, regardless of the specific medical conditions and diagnoses. To give an overview of the general effectiveness of active workplace interventions aimed at preventing and reducing sickness absence. We systematically searched PubMed, Embase, Psych-info, and ISI web of knowledge on 27 December 2011. Inclusion criteria were (i) participants over 18 years old with an active role in the intervention, (ii) intervention done partly or fully at the workplace or at the initiative of the workplace and (iii) sickness absence reported. Two reviewers independently screened articles, extracted data and assessed risk of bias. A narrative synthesis was used. We identified 2036 articles of which, 93 were assessed in full text. Seventeen articles were included (2 with low and 15 with medium risk of bias), with a total of 24 comparisons. Five interventions from four articles significantly reduced sickness absence. We found moderate evidence that graded activity reduced sickness absence and limited evidence that the Sheerbrooke model (a comprehensive multidisciplinary intervention) and cognitive behavioural therapy (CBT) reduced sickness absence. There was moderate evidence that workplace education and physical exercise did not reduce sickness absence. For other interventions, the evidence was insufficient to draw conclusions. The review found limited evidence that active workplace interventions were not generally effective in reducing sickness absence, but there was moderate evidence of effect for graded activity and limited evidence for the effectiveness of the Sheerbrooke model and CBT.

A Double-Resistive Active Power Filter System to Attenuate Harmonic Voltages of a Radial Power Distribution Feeder

DEFF Research Database (Denmark)

Sun, Xiaofeng; Han, Ruijing; Shen, Hong

2016-01-01

voltages. This paper proposes a double-resistive active power filter (D-RAPF) system consisting of a terminal-RAPF and an attenuation-RAPF for each individual harmonic. The terminal-RAPF operating as the characteristic impedance of the feeder is installed at the end bus to suppress harmonic propagation......Harmonic propagation between power-factor correction capacitors and system inductors seriously deteriorates power quality in a radial power distribution feeder. Installation of a resistive active power filter (RAPF) at the end bus only suppresses harmonic propagation, not attenuates harmonic...... at all harmonic frequencies. The attenuation-RAPF, whose control gain can be set according to the requirements of the harmonic voltage distortion limit, is installed at a specific position for each individual harmonic to attenuate the corresponding harmonic voltages. The D-RAPF system not only suppresses...

Implementation Intentions Reduce Implicit Stereotype Activation and Application.

Science.gov (United States)

Rees, Heather Rose; Rivers, Andrew Michael; Sherman, Jeffrey W

2018-05-01

Research has found that implementation intentions, if-then action plans (e.g., "if I see a Black face, I will think safe"), reduce stereotyping on implicit measures. However, it is unknown by what process(es) implementation intentions reduce implicit stereotyping. The present research examines the effects of implementation intentions on stereotype activation (e.g., extent to which stereotypic information is accessible) and stereotype application (e.g., extent to which accessible stereotypes are applied in judgment). In addition, we assessed the efficiency of implementation intentions by manipulating cognitive resources (e.g., digit-span, restricted response window) while participants made judgments on an implicit stereotyping measure. Across four studies, implementation intentions reduced implicit stereotyping. This decrease in stereotyping was associated with reductions in both stereotype activation and application. In addition, these effects of implementation intentions were highly efficient and associated with reduced stereotyping even for groups for which people may have little practice inhibiting stereotypes (e.g., gender).

Active and reactive power support of MV distribution systems using battery energy storage

DEFF Research Database (Denmark)

Wang, Jiawei; Hashemi Toghroljerdi, Seyedmostafa; You, Shi

2017-01-01

shaving and voltage support service from the perspective of Distribution System Operators (DSOs). An active power support algorithm is implemented and the effects of various load profiles as well as different Photovoltaic (PV) penetration scenarios on the operation of BESS and the optimal BESS converter......Adoption of Battery Energy Storage Systems (BESSs) for provision of grid services is increasing. This paper investigates the applications of BESS for the grid upgrade deferral and voltage support of Medium Voltage (MV) distribution systems. A BESS is modelled in Matlab/Simulink to perform peak load...... size for peak load shaving are investigated. The BESS annual lifetime degradation is also estimated using a rainflow counting algorithm. A reactive power support algorithm embedded with Q-U droop control is proposed in order to reduce the voltage drop in a part of 10 kV distribution network of Nordhavn...

Managing Siting Activities for Nuclear Power Plants

International Nuclear Information System (INIS)

2012-01-01

One of the IAEA's statutory objectives is to ''seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world''. One way this objective is achieved is through the publication of a range of technical series. Two of these are the IAEA Nuclear Energy Series and the IAEA Safety Standards Series. According to Article III.A.6 of the IAEA Statute, the safety standards establish 'standards of safety for protection of health and minimization of danger to life and property.' The safety standards include the Safety Fundamentals, Safety Requirements and Safety Guides. These standards are written primarily in a regulatory style, and are binding on the IAEA for its own programmes. The principal users are the regulatory bodies in Member States and other national authorities. The IAEA Nuclear Energy Series comprises reports designed to encourage and assist R and D on, and application of, nuclear energy for peaceful uses. This includes practical examples to be used by owners and operators of utilities in Member States, implementing organizations, academia, and government officials, among others. This information is presented in guides, reports on technology status and advances, and best practices for peaceful uses of nuclear energy based on inputs from international experts. The IAEA Nuclear Energy Series complements the IAEA Safety Standards Series. The introduction of nuclear power brings new challenges to States - one of them being the selection of appropriates sites. It is a project that needs to begin early, be well managed, and deploy good communications with all stakeholders; including regulators. This is important, not just for those States introducing nuclear power for the first time, but for any State looking to build a new nuclear power plant. The purpose of the siting activities goes beyond choosing a suitable site and acquiring a licence. A large part of the project is about producing and maintaining a validated

Managing Siting Activities for Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-06-15

One of the IAEA's statutory objectives is to ''seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world''. One way this objective is achieved is through the publication of a range of technical series. Two of these are the IAEA Nuclear Energy Series and the IAEA Safety Standards Series. According to Article III.A.6 of the IAEA Statute, the safety standards establish 'standards of safety for protection of health and minimization of danger to life and property.' The safety standards include the Safety Fundamentals, Safety Requirements and Safety Guides. These standards are written primarily in a regulatory style, and are binding on the IAEA for its own programmes. The principal users are the regulatory bodies in Member States and other national authorities. The IAEA Nuclear Energy Series comprises reports designed to encourage and assist R and D on, and application of, nuclear energy for peaceful uses. This includes practical examples to be used by owners and operators of utilities in Member States, implementing organizations, academia, and government officials, among others. This information is presented in guides, reports on technology status and advances, and best practices for peaceful uses of nuclear energy based on inputs from international experts. The IAEA Nuclear Energy Series complements the IAEA Safety Standards Series. The introduction of nuclear power brings new challenges to States - one of them being the selection of appropriates sites. It is a project that needs to begin early, be well managed, and deploy good communications with all stakeholders; including regulators. This is important, not just for those States introducing nuclear power for the first time, but for any State looking to build a new nuclear power plant. The purpose of the siting activities goes beyond choosing a suitable site and acquiring a licence. A large part of the project is about producing and maintaining a validated

Fatigue Load Sensitivity Based Optimal Active Power Dispatch For Wind Farms

DEFF Research Database (Denmark)

Zhao, Haoran; Wu, Qiuwei; Huang, Shaojun

2017-01-01

This paper proposes an optimal active power dispatch algorithm for wind farms based on Wind Turbine (WT) load sensitivity. The control objectives include tracking power references from the system operator and minimizing fatigue loads experienced by WTs. The sensitivity of WT fatigue loads to power...... sensitivity are derived, which significantly improves the computation efficiency of the local WT controller. The proposed algorithm can be implemented in different active power control schemes. Case studies were conducted with a wind farm under balance control for both low and high wind conditions...

Nuclear power reactor safety research activities in CIAE

International Nuclear Information System (INIS)

Pu Shendi; Huang Yucai; Xu Hanming; Zhang Zhongyue

1994-01-01

The power reactor safety research activities in CIAE are briefly reviewed. The research work performed in 1980's and 1990's is mainly emphasised, which is closely related to the design, construction and licensing review of Qinshan Nuclear Power Plant and the safety review of Guangdong Nuclear Power Station. Major achievements in the area of thermohydraulics, nuclear fuel, probabilistic safety assessment and severe accident researches are summarized. The foreseeable research plan for the near future, relating to the design and construction of 600 MWe PWR NPP at Qinshan Site (phase II development) is outlined

Design and Implementation of PIR-Array to Reduce Power Consumption for Iraq's Households

Directory of Open Access Journals (Sweden)

Nidhal Yousif Nasser

2016-12-01

Full Text Available The purpose of this study is to design and implement a model using PIR-sensors for motion detection to reduce the electrical power for designing smart home requirements for Iraq households. Reducing energy consumption of home appliances plays an important role in modern designs of smart homes. The PIR (passive infrared sensor has been designed to detect human motion and has many applications especially in security fields. The main concept of the proposed work in this paper has focused on controlling the electrical devices (appliances, based on the location of a person movement inside the home. The design of the circuit control has also been designed to run specific devices located closed to person position in a room by designing PIR sensor array mounted in different angles. The proposed work has been compared with normal state by finding consumption in power (kWh and tariffs belong to MoE-Iraq.

Device for measuring active, reactive and apparent power

Energy Technology Data Exchange (ETDEWEB)

Bartosinski, E.; Wieland, J.

1982-09-30

The plan consists of a traditional electrodynamic mechanism for measuring power (IM) supplemented by three switches, two rectifiers, resistor, included in parallel, and phaseshifting throttle included in series with the voltage coil of the IM. This makes it possible by selection to perform three types of measurements: active power of alternating current or power of direct current, only the voltage coils and the IM current are engaged; reactive power, the resistor and the throttle are additionally engaged by the aforementioned method; complete (apparent) power--the current and the voltage are supplied directly to the IM coils, but in contrast to the first case, through rectifiers. The influence of the highest harmonic components of voltage and current which are not significant for industrial measurements can be eliminated in necessary cases using filtering devices.

Active learning for noisy oracle via density power divergence.

Science.gov (United States)

Sogawa, Yasuhiro; Ueno, Tsuyoshi; Kawahara, Yoshinobu; Washio, Takashi

2013-10-01

The accuracy of active learning is critically influenced by the existence of noisy labels given by a noisy oracle. In this paper, we propose a novel pool-based active learning framework through robust measures based on density power divergence. By minimizing density power divergence, such as β-divergence and γ-divergence, one can estimate the model accurately even under the existence of noisy labels within data. Accordingly, we develop query selecting measures for pool-based active learning using these divergences. In addition, we propose an evaluation scheme for these measures based on asymptotic statistical analyses, which enables us to perform active learning by evaluating an estimation error directly. Experiments with benchmark datasets and real-world image datasets show that our active learning scheme performs better than several baseline methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impurity content of reduced-activation ferritic steels and a vanadium alloy

International Nuclear Information System (INIS)

Klueh, R.L.; Grossbeck, M.L.; Bloom, E.E.

1997-01-01

Inductively coupled plasma mass spectrometry was used to analyze a reduced-activation ferritic/martensitic steel and a vanadium alloy for low-level impurities that would compromise the reduced-activation characteristics of these materials. The ferritic steel was from the 5-ton IEA heat of modified F82H, and the vanadium alloy was from a 500-kg heat of V-4Cr-4Ti. To compare techniques for analysis of low concentrations of impurities, the vanadium alloy was also examined by glow discharge mass spectrometry. Two other reduced-activation steels and two commercial ferritic steels were also analyzed to determine the difference in the level of the detrimental impurities in the IEA heat and steels for which no extra effort was made to restrict some of the tramp impurities. Silver, cobalt, molybdenum, and niobium proved to be the tramp impurities of most importance. The levels observed in these two materials produced with present technology exceeded the limits for low activation for either shallow land burial or recycling. The chemical analyses provide a benchmark for the improvement in production technology required to achieve reduced activation; they also provide a set of concentrations for calculating decay characteristics for reduced-activation materials. The results indicate the progress that has been made and give an indication of what must still be done before the reduced-activation criteria can be achieved

Monitoring Biological Activity at Geothermal Power Plants

Energy Technology Data Exchange (ETDEWEB)

Peter Pryfogle

2005-09-01

The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE) characterizations have been conducted using water samples collected from geothermal plants located in California and Utah. In addition, the on-line performance of a commercial electrochemical monitor, the BIoGEORGE?, has been evaluated during extended deployments at geothermal facilities. This report provides a review of these techniques, presents data on their application from laboratory and field studies, and discusses their value in characterizing and monitoring biological activities at geothermal power plants.

Fuzzy-predictive direct power control implementation of a grid connected photovoltaic system, associated with an active power filter

International Nuclear Information System (INIS)

Ouchen, Sabir; Betka, Achour; Abdeddaim, Sabrina; Menadi, Abdelkrim

2016-01-01

Highlights: • An implementation on dSPACE 1104 of a double stage grid connected photovoltaic system, associated with an active power filter. • A fuzzy logic controller for maximum power point tracking of photovoltaic generator using a boost converter. • Predictive direct power control almost eliminates the effect of harmonics under a unite power factor. • The robustness of control strategies was examined in different irradiance level conditions. - Abstract: The present paper proposes a real time implementation of an optimal operation of a double stage grid connected photovoltaic system, associated with a shunt active power filter. On the photovoltaic side, a fuzzy logic based maximum power point taking control is proposed to track permanently the optimum point through an adequate tuning of a boost converter regardless the solar irradiance variations; whereas, on the grid side, a model predictive direct power control is applied, to ensure both supplying a part of the load demand with the extracted photovoltaic power, and a compensation of undesirable harmonic contents of the grid current, under a unity power factor operation. The implementation of the control strategies is conducted on a small scale photovoltaic system, controlled via a dSPACE 1104 single card. The obtained experimental results show on one hand, that the proposed Fuzzy logic based maximum power taking point technique provides fast and high performances under different irradiance levels while compared with a sliding mode control, and ensures 1.57% more in efficiency. On the other hand, the predictive power control ensures a flexible settlement of active power amounts exchanges with the grid, under a unity power functioning. Furthermore, the grid current presents a sinusoidal shape with a tolerable total harmonic distortion coefficient 4.71%.

Effectiveness of state climate and energy policies in reducing power-sector CO2 emissions

Science.gov (United States)

Martin, Geoff; Saikawa, Eri

2017-12-01

States have historically been the primary drivers of climate change policy in the US, particularly with regard to emissions from power plants. States have implemented policies designed either to directly curb greenhouse gas (GHG) emissions from power plants, or to encourage energy efficiency and renewable energy growth. With the federal government withdrawing from the global climate agreement, understanding which state-level policies have successfully mitigated power-plant emissions is urgent. Past research has assessed policy effectiveness using data for periods before the adoption of many policies. We assess 17 policies using the latest data on state-level power-sector CO2 emissions. We find that policies with mandatory compliance are reducing power-plant emissions, while voluntary policies are not. Electric decoupling, mandatory GHG registry/reporting and public benefit funds are associated with the largest reduction in emissions. Mandatory GHG registry/reporting and public benefit funds are also associated with a large reduction in emissions intensity.

Experimental evaluation of a self-powered smart damping system in reducing vibrations of a full-scale stay cable

International Nuclear Information System (INIS)

Kim, In-Ho; Jung, Hyung-Jo; Koo, Jeong-Hoi

2010-01-01

This paper investigates the effectiveness of a self-powered smart damping system consisting of a magnetorheological (MR) damper and an electromagnetic induction (EMI) device in reducing cable vibrations. The proposed smart damping system incorporates an EMI device, which is capable of converting vibration energy into useful electrical energy. Thus, the incorporated EMI device can be used as an alternative power source for the MR damper, making it a self-powering system. The primary goal of this experimental study is to evaluate the performance of the proposed smart damping system using a full-scale, 44.7 m long, high-tension cable. To this end, an EMI part and an MR damper were designed and manufactured. Using a cable test setup in a laboratory setting, a series of tests were performed to evaluate the effectiveness of the self-powered smart damping system in reducing free vibration responses of the cable. The performances of the proposed smart damping system are compared with those of an equivalent passive system. Moreover, the damping characteristics of the smart damping system and the passive system are compared. The experimental results show that the self-powered smart damping system outperforms the passive control cases in reducing the vibrations of the cable. The results also show that the EMI can operate the smart damping system as a sole power source, demonstrating the feasibility of the self-powering capability of the system

Regulation techniques for smoothing active power in aggregated wind farms distributed within Spain

Energy Technology Data Exchange (ETDEWEB)

Martin-Martinez, Sergio; Vigueras-Rodriguez, Antonio; Gomez-Lazaro, Emilio [Universidad de Castilla-La Mancha, Albacete (Spain). Renewable Energy Research Inst.

2009-07-01

With the increasing production of wind power worldwide, power fluctuations have an impact on power system operation and costs. Power systems with high wind penetration gives rise to concerns about the adverse effects of wind farms on power operations and its staability. The integration of the power produced by wind farms is evaluated through ramp rates calculated as suggested by Parson et al. The worst cases regarding the power system are the most negative ramp rates in the Wind Farm, where the Power System has to compensate such drops in the wind power production. In most onshore wind farms production fluctuates much less than in offshore farms, due to two main reasons. First, offshore wind turbines are collected in a more reduced area, so fluctuations are more correlated. In addition, offshore meteorological conditions are often different than onshore. Furthermore, the variability of wind power is reduced when looking at a large interconnected sytem with geographically dispersed wind power production. This paper deals with a comparison of the smoothed out variability of wind power production time series for the single and aggregated wind farms, parting from their wind power production. The data analyzed come from a 1 year-period measurements of 9 wind farms spread over Spain. (orig.)

Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

International Nuclear Information System (INIS)

Suarez-Antola, Roberto; Ministerio de Industria, Energia y Mineria, Montevideo

2011-01-01

One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems to remain inside a certain bounded set of admissible states and state variations. In the framework of an analytic or numerical modeling process of a BWR power plant, this could imply first to find a suitable approximation to the solution manifold of the differential equations describing the stability behavior, and then a classification of the different solution types concerning their relation with the operational safety of the power plant. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is generalized and used to exemplify the analytical approach developed here. A nonlinear integral-differential equation in the logarithmic power is derived. Introducing a KBM Ansatz, a coupled set of two nonlinear ordinary differential equations is obtained. Analytical formulae are derived for the frequency of oscillation and the parameters that determine the stability of the steady states, including sub- and supercritical PAH bifurcations. A Bautin's bifurcation scenario seems possible on the power-flow plane: near the boundary of stability, a region where stable steady states are surrounded by unstable limit cycles surrounded at their turn by stable limit cycles. The analytical results are compared with recent digital simulations and applications of semi-analytical bifurcation theory done with reduced order models of BWR. (author)

Design and Tuning Methodology of Active Power Controller in Wind Power Plants

DEFF Research Database (Denmark)

Ionita, Claudiu; Raducu, Alin George; Iov, Florin

2017-01-01

This paper presents a method to design and tune the main controller of a Wind Power Plant (WPP), with focus on the active power and frequency control. The controller requirements are based on the Danish grid codes. The controller functionality is successfully verified using the model and the layout...... of an actual WPP rated at 160 MW, that consists of 80 wind turbines. Two reference dispatch strategies are investigated, equal and proportional. The proportional dispatch is preferred due to better tracking accuracy and robustness. The work described in this article is meant to help WPP developers...

Reduced ceramide synthase 2 activity causes progressive myoclonic epilepsy

DEFF Research Database (Denmark)

Mosbech, Mai-Britt; Olsen, Anne S B; Neess, Ditte

2014-01-01

between genes involved in SL metabolism and epilepsy. METHODS: We used quantitative real-time PCR, Western blotting, and enzymatic assays to determine the mRNA, protein, and activity levels of ceramide synthase 2 (CERS2) in fiibroblasts isolated from parental control subjects and from a patient diagnosed...... with progressive myoclonic epilepsy (PME). Mass spectrometry and fluorescence microscopy were used to examine the effects of reduced CERS2 activity on cellular lipid composition and plasma membrane functions. RESULTS: We identify a novel 27 kb heterozygous deletion including the CERS2 gene in a proband diagnosed...... with PME. Compared to parental controls, levels of CERS2 mRNA, protein, and activity were reduced by ˜50% in fibroblasts isolated from this proband, resulting in significantly reduced levels of ceramides and sphingomyelins containing the very long-chain fatty acids C24:0 and C26:0. The change in SL...

Distributed Reactive Power Control based Conservation Voltage Reduction in Active Distribution Systems

Directory of Open Access Journals (Sweden)

EMIROGLU, S.

2017-11-01

Full Text Available This paper proposes a distributed reactive power control based approach to deploy Volt/VAr optimization (VVO / Conservation Voltage Reduction (CVR algorithm in a distribution network with distributed generations (DG units and distribution static synchronous compensators (D-STATCOM. A three-phase VVO/CVR problem is formulated and the reactive power references of D-STATCOMs and DGs are determined in a distributed way by decomposing the VVO/CVR problem into voltage and reactive power control. The main purpose is to determine the coordination between voltage regulator (VR and reactive power sources (Capacitors, D-STATCOMs and DGs based on VVO/CVR. The study shows that the reactive power injection capability of DG units may play an important role in VVO/CVR. In addition, it is shown that the coordination of VR and reactive power sources does not only save more energy and power but also reduces the power losses. Moreover, the proposed VVO/CVR algorithm reduces the computational burden and finds fast solutions. To illustrate the effectiveness of the proposed method, the VVO/CVR is performed on the IEEE 13-node test system feeder considering unbalanced loading and line configurations. The tests are performed taking the practical voltage-dependent load modeling and different customer types into consideration to improve accuracy.

An integrated control method for a wind farm to reduce frequency deviations in a small power system

International Nuclear Information System (INIS)

Kaneko, Toshiaki; Uehara, Akie; Senjyu, Tomonobu; Yona, Atsushi; Urasaki, Naomitsu

2011-01-01

Output power of wind turbine generator (WTG) is not constant and fluctuates due to wind speed changes. To reduce the adverse effects of the power system introducing WTGs, there are several published reports on output power control of WTGs detailing various researches based on pitch angle control, variable speed wind turbines, energy storage systems, and so on. In this context, this paper presents an integrated control method for a WF to reduce frequency deviations in a small power system. In this study, the WF achieves the frequency control with two control schemes: load estimation and short-term ahead wind speed prediction. For load estimation in the small power system, a minimal-order observer is used as disturbance observer. The estimated load is utilized to determine the output power command of the WF. To regulate the output power command of the WF according to wind speed changing, short-term ahead wind speed is predicted by using least-squares method. The predicted wind speed adjusts the output power command of the WF as a multiplying factor with fuzzy reasoning. By means of the proposed method, the WF can operate according to the wind and load conditions. In the WF system, each output power of the WTGs is controlled by regulating each pitch angle. For increasing acquisition power of the WF, a dispatch control method also is proposed. In the pitch angle control system of each WTG, generalized predictive control (GPC) is applied to enhance the control performance. Effectiveness of the proposed method is verified by the numerical simulations.

Evaluation of a fast power demand response strategy using active and passive building cold storages for smart grid applications

International Nuclear Information System (INIS)

Cui, Borui; Wang, Shengwei; Yan, Chengchu; Xue, Xue

2015-01-01

Highlights: • A fast power demand response strategy is developed for smart grid applications. • The developed strategy can provide immediate and stepped power demand reduction. • The demand reduction and building indoor temperature can be predicted accurately. • The demand reduction during the DR event is stable. - Abstract: Smart grid is considered as a promising solution in improving the power reliability and sustainability where demand response is one important ingredient. Demand response (DR) is a set of demand-side activities to reduce or shift electricity use to improve the electric grid efficiency and reliability. This paper presents the investigations on the power demand alternation potential for buildings involving both active and passive cold storages to support the demand response of buildings connected to smart grids. A control strategy is developed to provide immediate and stepped power demand reduction through shutting chiller(s) down when requested. The primary control objective of the developed control strategy is to restrain the building indoor temperature rise as to maintain indoor thermal comfort within certain level during the DR event. The chiller power reduction is also controlled under certain power reduction set-point. The results show that stepped and significant power reduction can be achieved through shutting chiller(s) down when requested. The power demand reduction and indoor temperature during the DR event can be also predicted accurately. The power demand reduction is stable which is predictable for the system operators

Adaptive intelligent power systems: Active distribution networks

International Nuclear Information System (INIS)

McDonald, Jim

2008-01-01

Electricity networks are extensive and well established. They form a key part of the infrastructure that supports industrialised society. These networks are moving from a period of stability to a time of potentially major transition, driven by a need for old equipment to be replaced, by government policy commitments to cleaner and renewable sources of electricity generation, and by change in the power industry. This paper looks at moves towards active distribution networks. The novel transmission and distribution systems of the future will challenge today's system designs. They will cope with variable voltages and frequencies, and will offer more flexible, sustainable options. Intelligent power networks will need innovation in several key areas of information technology. Active control of flexible, large-scale electrical power systems is required. Protection and control systems will have to react to faults and unusual transient behaviour and ensure recovery after such events. Real-time network simulation and performance analysis will be needed to provide decision support for system operators, and the inputs to energy and distribution management systems. Advanced sensors and measurement will be used to achieve higher degrees of network automation and better system control, while pervasive communications will allow networks to be reconfigured by intelligent systems

Hydroxychloroquine reduces microglial activity and attenuates experimental autoimmune encephalomyelitis.

Science.gov (United States)

Koch, Marcus W; Zabad, Rana; Giuliani, Fabrizio; Hader, Walter; Lewkonia, Ray; Metz, Luanne; Wee Yong, V

2015-11-15

Microglial activation is thought to be a key pathophysiological mechanism underlying disease activity in all forms of MS. Hydroxychloroquine (HCQ) is an antimalarial drug with immunomodulatory properties that is widely used in the treatment of rheumatological diseases. In this series of experiments, we explore the effect of HCQ on human microglial activation in vitro and on the development of experimental autoimmune encephalitis (EAE) in vivo. We activated human microglia with lipopolysaccharide (LPS), and measured concentrations of several pro- and anti-inflammatory cytokines in untreated and HCQ pretreated cultures. We investigated the effect of HCQ pretreatment at two doses on the development of EAE and spinal cord histology. HCQ pretreatment reduced the production of pro-inflammatory (TNF-alpha, IL-6, and IL-12) and anti-inflammatory (IL-10 and IL-1 receptor antagonist) cytokines in LPS-stimulated human microglia. HCQ pretreatment delayed the onset of EAE, and reduced the number of Iba-1 positive microglia/macrophages and signs of demyelination in the spinal cords of HCQ treated animals. HCQ treatment reduces the activation of human microglia in vitro, delays the onset of EAE, and decreases the representation of activated macrophages/microglia and demyelination in the spinal cord of treated mice. HCQ is a plausible candidate for further clinical studies in MS. Copyright © 2015 Elsevier B.V. All rights reserved.

Paperless activation. Optimization potentials in power plants; Papierlose Freischaltung. Optimierungspotenziale im Kraftwerk

Energy Technology Data Exchange (ETDEWEB)

Goestenkors, Robert [Gemeinschaftskraftwerk Bergkamen der Evonik Steag GmbH und RWE Power AG, Bergkamen (Germany); Wieder, Ralf [Arbeitssicherheit fuer die Kraftwerke der Evonik Steag GmbH, Essen (Germany)

2011-03-15

Activation of plants or components is a very important task in any power plant. Evonik Steag started to use computer-assisted activation procedures many years ago. The operation management system SI {sup registered} was developed by the Evonik Steag subsidiary Evonik Energy Services; it comprises and activation module that manages the planning and execution of activation and connection processes for all aggregates of a power plant. The module was now extended to support also local activation operators. Instead of documents on paper, the activation operator receives a PDA description of the steps to be taken. The correct following of the procedure is ensured by a RFID chip connected at the activation site. Documentation of the activation is still carried out by signing a paper document. Further developments are still required to make the whole activation process at Bergkamen power plant paperless. The contribution describes the current status and the first step that was taken and then proceeds to describe the implemented paperless activation procedure.

Reducing costs of wind power with a gearless permanent-magnet generator

International Nuclear Information System (INIS)

Vihriaelae, H.; Peraelae, R.; Soederlund, L.; Eriksson, J.T.

1995-01-01

This article examines a disc-type axial-field permanent magnet generator (PMG) utilizing the latest generation of permanent magnet material, namely Nd 15 B 8 Fe 77 . A frequency converter (FC) is needed to keep the system synchronized with the grid. It also offers a possibility to use variable speed. The main advantages of this novel system compared to the conventional one are a higher overall efficiency, better reliability, reduced weight and diminished need for maintenance, all contributing to the cost-reduction of wind power. (author)

Response of Cultured Neuronal Network Activity After High-Intensity Power Frequency Magnetic Field Exposure

Directory of Open Access Journals (Sweden)

Atsushi Saito

2018-03-01

Full Text Available High-intensity and low frequency (1–100 kHz time-varying electromagnetic fields stimulate the human body through excitation of the nervous system. In power frequency range (50/60 Hz, a frequency-dependent threshold of the external electric field-induced neuronal modulation in cultured neuronal networks was used as one of the biological indicator in international guidelines; however, the threshold of the magnetic field-induced neuronal modulation has not been elucidated. In this study, we exposed rat brain-derived neuronal networks to a high-intensity power frequency magnetic field (hPF-MF, and evaluated the modulation of synchronized bursting activity using a multi-electrode array (MEA-based extracellular recording technique. As a result of short-term hPF-MF exposure (50–400 mT root-mean-square (rms, 50 Hz, sinusoidal wave, 6 s, the synchronized bursting activity was increased in the 400 mT-exposed group. On the other hand, no change was observed in the 50–200 mT-exposed groups. In order to clarify the mechanisms of the 400 mT hPF-MF exposure-induced neuronal response, we evaluated it after blocking inhibitory synapses using bicuculline methiodide (BMI; subsequently, increase in bursting activity was observed with BMI application, and the response of 400 mT hPF-MF exposure disappeared. Therefore, it was suggested that the response of hPF-MF exposure was involved in the inhibitory input. Next, we screened the inhibitory pacemaker-like neuronal activity which showed autonomous 4–10 Hz firing with CNQX and D-AP5 application, and it was confirmed that the activity was reduced after 400 mT hPF-MF exposure. Comparison of these experimental results with estimated values of the induced electric field (E-field in the culture medium revealed that the change in synchronized bursting activity occurred over 0.3 V/m, which was equivalent to the findings of a previous study that used the external electric fields. In addition, the results suggested that

Control Strategy of Active Power Filter Based on Modular Multilevel Converter

Science.gov (United States)

Xie, Xifeng

2018-03-01

To improve the capacity, pressure resistance and the equivalent switching frequency of active power filter (APF), a control strategy of APF based on Modular Multilevel Converter (MMC) is presented. In this Control Strategy, the indirect current control method is used to achieve active current and reactive current decoupling control; Voltage Balance Control Strategy is to stabilize sub-module capacitor voltage, the predictive current control method is used to Track and control of harmonic currents. As a result, the harmonic current is restrained, and power quality is improved. Finally, the simulation model of active power filter controller based on MMC is established in Matlab/Simulink, the simulation proves that the proposed strategy is feasible and correct.

A Low Power, Parallel Wearable Multi-Sensor System for Human Activity Evaluation.

Science.gov (United States)

Li, Yuecheng; Jia, Wenyan; Yu, Tianjian; Luan, Bo; Mao, Zhi-Hong; Zhang, Hong; Sun, Mingui

2015-04-01

In this paper, the design of a low power heterogeneous wearable multi-sensor system, built with Zynq System-on-Chip (SoC), for human activity evaluation is presented. The powerful data processing capability and flexibility of this SoC represent significant improvements over our previous ARM based system designs. The new system captures and compresses multiple color images and sensor data simultaneously. Several strategies are adopted to minimize power consumption. Our wearable system provides a new tool for the evaluation of human activity, including diet, physical activity and lifestyle.

Optimizing power plant cycling operations while reducing generating plant damage and costs

Energy Technology Data Exchange (ETDEWEB)

Lefton, S A; Besuner, P H; Grimsrud, P [Aptech Engineering Services, Inc., Sunnyvale, CA (United States); Bissel, A [Electric Supply Board, Dublin (Ireland)

1999-12-31

This presentation describes a method for analyzing, quantifying, and minimizing the total cost of fossil, combined cycle, and pumped hydro power plant cycling operation. The method has been developed, refined, and applied during engineering studies at some 160 units in the United States and 8 units at the Irish Electric Supply Board (ESB) generating system. The basic premise of these studies was that utilities are underestimating the cost of cycling operation. The studies showed that the cost of cycling conventional boiler/turbine fossil power plants can range from between $2,500 and $500,000 per start-stop cycle. It was found that utilities typically estimate these costs by factors of 3 to 30 below actual costs and, thus, often significantly underestimate their true cycling costs. Knowledge of the actual, or total, cost of cycling will reduce power production costs by enabling utilities to more accurately dispatch their units to manage unit life expectancies, maintenance strategies and reliability. Utility management responses to these costs are presented and utility cost savings have been demonstrated. (orig.) 7 refs.

Optimizing power plant cycling operations while reducing generating plant damage and costs

Energy Technology Data Exchange (ETDEWEB)

Lefton, S.A.; Besuner, P.H.; Grimsrud, P. [Aptech Engineering Services, Inc., Sunnyvale, CA (United States); Bissel, A. [Electric Supply Board, Dublin (Ireland)

1998-12-31

This presentation describes a method for analyzing, quantifying, and minimizing the total cost of fossil, combined cycle, and pumped hydro power plant cycling operation. The method has been developed, refined, and applied during engineering studies at some 160 units in the United States and 8 units at the Irish Electric Supply Board (ESB) generating system. The basic premise of these studies was that utilities are underestimating the cost of cycling operation. The studies showed that the cost of cycling conventional boiler/turbine fossil power plants can range from between $2,500 and $500,000 per start-stop cycle. It was found that utilities typically estimate these costs by factors of 3 to 30 below actual costs and, thus, often significantly underestimate their true cycling costs. Knowledge of the actual, or total, cost of cycling will reduce power production costs by enabling utilities to more accurately dispatch their units to manage unit life expectancies, maintenance strategies and reliability. Utility management responses to these costs are presented and utility cost savings have been demonstrated. (orig.) 7 refs.

Experimental study on solar-powered adsorption refrigeration cycle with activated alumina and activated carbon as adsorbent

Directory of Open Access Journals (Sweden)

Himsar Ambarita

2016-03-01

Full Text Available Typical adsorbent applied in solar-powered adsorption refrigeration cycle is activated carbon. It is known that activated alumina shows a higher adsorption capacity when it is tested in the laboratory using a constant radiation heat flux. In this study, solar-powered adsorption refrigeration cycle with generator filled by different adsorbents has been tested by exposing to solar radiation in Medan city of Indonesia. The generator is heated using a flat-plate type solar collector with a dimension of 0.5 m×0.5 m. Four cases experiments of solar-powered adsorption cycle were carried out, they are with generator filled by 100% activated alumina (named as 100AA, by a mixed of 75% activated alumina and 25% activated carbon (75AA, by a mixed of 25% activated alumina and 75% activated carbon (25AA, and filled by 100% activated carbon. Each case was tested for three days. The temperature and pressure history and the performance have been presented and analyzed. The results show that the average COP of 100AA, 75AA, 25AA, and 100AC is 0.054, 0.056, 0.06, and 0.074, respectively. The main conclusion can be drawn is that for Indonesian condition and flat-plate type solar collector the pair of activated carbon and methanol is the better than activated alumina.

The Control of Transmitted Power in an Active Isolation System

DEFF Research Database (Denmark)

Elliott, S.J.; Gardonio, P.; Pinnington, R.J.

1997-01-01

The isolation of vibration through a system with multiple active mounts is discussed, in which each of the mounts can transmit vibration in several degrees of freedom. Theoretical models of the various parts of this system have been developed which include a flexible receiving structure and distr......The isolation of vibration through a system with multiple active mounts is discussed, in which each of the mounts can transmit vibration in several degrees of freedom. Theoretical models of the various parts of this system have been developed which include a flexible receiving structure...... and distributed active mounts, and these models can be connected together to produce an overall theoretical description of a realistic active isolation system. Total transmitted power has been found to be an excellent criterion to quantify the effect of various control strategies in this model in which...... the contributions to the transmitted power in the various degrees of freedom can be clearly understood. It has also been found, however, that an active control system which minimises a practical estimate of transmitted power, calculated from the product of the axial forces and velocities under the mounts, can give...

Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

Energy Technology Data Exchange (ETDEWEB)

Suarez-Antola, Roberto, E-mail: roberto.suarez@miem.gub.u, E-mail: rsuarez@ucu.edu.u [Universidad Catolica del Uruguay, Montevideo (Uruguay). Fac. de Ingenieria y Tecnologias. Dept. de Matematica; Ministerio de Industria, Energia y Mineria, Montevideo (Uruguay). Direccion General de Secretaria

2011-07-01

One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems to remain inside a certain bounded set of admissible states and state variations. In the framework of an analytic or numerical modeling process of a BWR power plant, this could imply first to find a suitable approximation to the solution manifold of the differential equations describing the stability behavior, and then a classification of the different solution types concerning their relation with the operational safety of the power plant. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is generalized and used to exemplify the analytical approach developed here. A nonlinear integral-differential equation in the logarithmic power is derived. Introducing a KBM Ansatz, a coupled set of two nonlinear ordinary differential equations is obtained. Analytical formulae are derived for the frequency of oscillation and the parameters that determine the stability of the steady states, including sub- and supercritical PAH bifurcations. A Bautin's bifurcation scenario seems possible on the power-flow plane: near the boundary of stability, a region where stable steady states are surrounded by unstable limit cycles surrounded at their turn by stable limit cycles. The analytical results are compared with recent digital simulations and applications of semi-analytical bifurcation theory done with reduced order models of BWR. (author)

HARMONICS ANALYSIS OF SYSTEM USING SHUNT ACTIVE POWER FILTER BY MATLAB SIMULATION

OpenAIRE

VAISHALI PARDHI; Dr.A K KORI

2017-01-01

The widely use of nonlinear loads, such as diode and thyristor, rectifiers, computers, consumer electronics, uninterruptible power supplies and adjustable speed drives results in the distorted current waveforms in the electrical distribution systems. Harmonics is a major problem in power systems that have become serious recently owing to the wide use of power electronics-related equipment. The input power factor of most of these equipments is poor. There is a great need to reduce these harmon...

Using Pretwist to Reduce Power Loss of Bend-Twist Coupled Blades

DEFF Research Database (Denmark)

Stäblein, Alexander; Tibaldi, Carlo; Hansen, Morten Hartvig

2016-01-01

Bend-twist coupling of wind turbine blades is known as a means to reduce the structural loads of the turbine. While the load reduction is desirable, bend-twist coupling also leads to a decrease in the annual energy production of the turbine. The reduction is mainly related to a no longer optimal......, and fatigue load for the DTU 10 MW Reference Wind Turbine. The analysis was carried out by calculating the nonlinear steady state rotor deflection in an uniform inflow over the operational range of the turbine. The steady state power curve together with a Rayleigh wind speed distribution has been used...... to estimate the annual energy production. The turbine model was then linearised around the steady state and the power spectral density of the blade response, which was computed from transfer functions and the wind speed variations in the frequency domain, was used to estimate the fatigue loads by a spectral...

Teollisuuden Voima Oy - Industrial Power Company Ltd. Local information activity

Energy Technology Data Exchange (ETDEWEB)

Engros, Taina [Department of Information, TVO, Olkiluoto FIN-27160 (Finland)

1989-07-01

There are two nuclear power producers in Finland - the state-owned power company Imatran Voima Oy which operates two 440 MW Soviet-made PWR units in southern Finland, east of Helsinki and the Teollisuuden Voima Oy - Industrial Power Company Ltd, or TVO, owned by Finnish industrial companies. TVO operates two 710 MW ABB ATOM BWR units producing about one fifth of the country's electricity consumption. Operating experiences are extremely good from all Finnish nuclear power plants. The Finns' attitude towards nuclear power has changed into a positive direction in recent times. This can probably be noted as an international trend now that the Chernobyl accident is becoming an incident of the past. The Finnish citizens and politicians are facing two questions; first, what is their attitude towards nuclear power as a source of energy, in other words, do they approve of the plants currently in operation. The second question is how they stand on the building of new plants. It is probably another universal phenomenon that the attitudes of people living in the vicinity of nuclear power plants are less critical than the attitudes of those living farther away. This does not, by any means, result in local information activity being easier or less important than nationwide information activity. On the contrary, local decision-makers, local media and inhabitants are those who can, and through whom we can, influence also wider circles. The Nuclear Energy Act, which became effective in Finland last year, defines that the final decision on whether nuclear power plants can be built inside a municipality, is made at local level. As far as TVO is concerned one factor making local information activity easier is the small size of the locality. The difficulty TVO has to face is the people's suspicion of information activity. All information is considered propaganda, regardless of its form, and only negative news are considered information. Also, a large proportion of people are passive

Teollisuuden Voima Oy - Industrial Power Company Ltd. Local information activity

International Nuclear Information System (INIS)

Engros, Taina

1989-01-01

There are two nuclear power producers in Finland - the state-owned power company Imatran Voima Oy which operates two 440 MW Soviet-made PWR units in southern Finland, east of Helsinki and the Teollisuuden Voima Oy - Industrial Power Company Ltd, or TVO, owned by Finnish industrial companies. TVO operates two 710 MW ABB ATOM BWR units producing about one fifth of the country's electricity consumption. Operating experiences are extremely good from all Finnish nuclear power plants. The Finns' attitude towards nuclear power has changed into a positive direction in recent times. This can probably be noted as an international trend now that the Chernobyl accident is becoming an incident of the past. The Finnish citizens and politicians are facing two questions; first, what is their attitude towards nuclear power as a source of energy, in other words, do they approve of the plants currently in operation. The second question is how they stand on the building of new plants. It is probably another universal phenomenon that the attitudes of people living in the vicinity of nuclear power plants are less critical than the attitudes of those living farther away. This does not, by any means, result in local information activity being easier or less important than nationwide information activity. On the contrary, local decision-makers, local media and inhabitants are those who can, and through whom we can, influence also wider circles. The Nuclear Energy Act, which became effective in Finland last year, defines that the final decision on whether nuclear power plants can be built inside a municipality, is made at local level. As far as TVO is concerned one factor making local information activity easier is the small size of the locality. The difficulty TVO has to face is the people's suspicion of information activity. All information is considered propaganda, regardless of its form, and only negative news are considered information. Also, a large proportion of people are passive

Reducing costs of wind power with a gearless permanent-magnet generator

Energy Technology Data Exchange (ETDEWEB)

Vihriaelae, H; Peraelae, R; Soederlund, L; Eriksson, J T [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism

1996-12-31

This article examines a disc-type axial-field permanent magnet generator (PMG) utilizing the latest generation of permanent magnet material, namely Nd{sub 15}B{sub 8}Fe{sub 77}. A frequency converter (FC) is needed to keep the system synchronized with the grid. It also offers a possibility to use variable speed. The main advantages of this novel system compared to the conventional one are a higher overall efficiency, better reliability, reduced weight and diminished need for maintenance, all contributing to the cost-reduction of wind power. (author)

Reducing costs of wind power with a gearless permanent-magnet generator

Energy Technology Data Exchange (ETDEWEB)

Vihriaelae, H.; Peraelae, R.; Soederlund, L.; Eriksson, J.T. [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism

1995-12-31

This article examines a disc-type axial-field permanent magnet generator (PMG) utilizing the latest generation of permanent magnet material, namely Nd{sub 15}B{sub 8}Fe{sub 77}. A frequency converter (FC) is needed to keep the system synchronized with the grid. It also offers a possibility to use variable speed. The main advantages of this novel system compared to the conventional one are a higher overall efficiency, better reliability, reduced weight and diminished need for maintenance, all contributing to the cost-reduction of wind power. (author)

Active power reserves evaluation in large scale PVPPs

DEFF Research Database (Denmark)

Crăciun, Bogdan-Ionut; Kerekes, Tamas; Sera, Dezso

2013-01-01

The present trend on investing in renewable ways of producing electricity in the detriment of conventional fossil fuel-based plants will lead to a certain point where these plants have to provide ancillary services and contribute to overall grid stability. Photovoltaic (PV) power has the fastest...... growth among all renewable energies and managed to reach high penetration levels creating instabilities which at the moment are corrected by the conventional generation. This paradigm will change in the future scenarios where most of the power is supplied by large scale renewable plants and parts...... of the ancillary services have to be shared by the renewable plants. The main focus of the proposed paper is to technically and economically analyze the possibility of having active power reserves in large scale PV power plants (PVPPs) without any auxiliary storage equipment. The provided reserves should...

Self-powered suspension criterion and energy regeneration implementation scheme of motor-driven active suspension

Science.gov (United States)

Yan, Shuai; Sun, Weichao

2017-09-01

Active suspension systems have advantages on mitigating the effects of vehicle vibration caused by road roughness, which are one of the most important component parts in influencing the performances of vehicles. However, high amount of energy consumption restricts the application of active suspension systems. From the point of energy saving, this paper presents a self-powered criterion of the active suspension system to judge whether a motor-driven suspension can be self-powered or not, and then a motor parameter condition is developed as a reference to design a self-powered suspension. An energy regeneration implementation scheme is subsequently proposed to make the active suspension which has the potential to be self-powered achieve energy-saving target in the real application. In this implementation scheme, operating electric circuits are designed based on different working status of the actuator and power source and it is realizable to accumulate energy from road vibration and supply energy to the actuator by switching corresponding electric circuits. To apply the self-powered suspension criterion and energy regeneration implementation scheme, an active suspension system is designed with a constrained H∞ controller and calculation results indicate that it has the capability to be self-powered. Simulation results show that the performances of the self-powered active suspension are nearly the same as those of the active suspension with an external energy source and can achieve energy regeneration at the same time.

Indirect control of a single-phase active power filter

Directory of Open Access Journals (Sweden)

Mihai CULEA

2006-12-01

Full Text Available The control of shunt active power filters using PWM inverters consists in generating a reference by separating, using different methods, the harmonics to be eliminated. The methods used are time-consuming and need dedicated control and signal processing equipments. To avoid these setbacks a new method is proposed in the paper. The active power filter is a current PWM rectifier with voltage output and with a capacitor on the DC side. The PWM rectifier is controlled so that the sum of its current and the load’s current is a sinusoid. The control block as well as simulation results are presented.

Design, control, and implementation of LCL-filter-based shunt active power filters

DEFF Research Database (Denmark)

Tang, Yi; Loh, Poh Chiang; Wang, Peng

2011-01-01

This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offer......-loop control system, and active damping implemented with fewer current sensors are all addressed here. An analytical design example is finally presented, being supported with experimental results, to verify its effectiveness and practicality.......This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offers...

Reduced auditory efferent activity in childhood selective mutism.

Science.gov (United States)

Bar-Haim, Yair; Henkin, Yael; Ari-Even-Roth, Daphne; Tetin-Schneider, Simona; Hildesheimer, Minka; Muchnik, Chava

2004-06-01

Selective mutism is a psychiatric disorder of childhood characterized by consistent inability to speak in specific situations despite the ability to speak normally in others. The objective of this study was to test whether reduced auditory efferent activity, which may have direct bearings on speaking behavior, is compromised in selectively mute children. Participants were 16 children with selective mutism and 16 normally developing control children matched for age and gender. All children were tested for pure-tone audiometry, speech reception thresholds, speech discrimination, middle-ear acoustic reflex thresholds and decay function, transient evoked otoacoustic emission, suppression of transient evoked otoacoustic emission, and auditory brainstem response. Compared with control children, selectively mute children displayed specific deficiencies in auditory efferent activity. These aberrations in efferent activity appear along with normal pure-tone and speech audiometry and normal brainstem transmission as indicated by auditory brainstem response latencies. The diminished auditory efferent activity detected in some children with SM may result in desensitization of their auditory pathways by self-vocalization and in reduced control of masking and distortion of incoming speech sounds. These children may gradually learn to restrict vocalization to the minimal amount possible in contexts that require complex auditory processing.

Background activity values from the nuclear power plants at the spanish coast

International Nuclear Information System (INIS)

Montesinos, M.

1979-01-01

The radiological data obtained from gross alpha and beta measurements are exposed. Also the activity of differents long lived radionuclides from a significant number of the Cantabric coast sea biota samples is given, where the Lemoniz nuclear power plant is located, as well as those from the Mediterranean coast, where the Vandellos nuclear power plant is sitting. The activity transfer through the different steps of the food-chain in each biota sample, as well as the activity values for sediments and water are presented. Eventually, a comparatif study of the background activity values between the two coasts mentioned above, is made. Also a comparison between the preoperational and operational values for the operating Vandellos nuclear power plant is described. (author)

An active trap filter for high-power voltage source converters

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

2015-01-01

This paper proposes a power electronic based device to actively trap the switching current ripples for highpower converters. Control principle and system design of the active trap filter are discussed first. Comparisons of the active trap filter with LCL and LLCL filters are then carried out...

Increasing coal-fired power generation efficiency to reduce electric cost and environmental emissions

International Nuclear Information System (INIS)

Torrens, I.M.; Stenzel, W.C.

1997-01-01

New generating capacity required globally between 1993 and 2010 is estimated to be around 1500 GW, of which some two-thirds will be outside the OECD, and some 40 % in the Asian non-OECD countries. Coal is likely to account for a substantial fraction of this new generation. Today's state-of-the-art supercritical coal-fired power plant has a conversion efficiency of some 42-45 %. The capital cost increase associated with the supercritical or ultra-supercritical pulverized coal power plant compared to a conventional subcritical plant is small to negligible. The increased efficiency associated with the supercritical plant leads to an actual reduction in the total cost of electricity generated in cents/kWh, relative to a conventional plant. Despite this, the power sector continues to build subcritical plants and has no near term plans to increase the efficiency of power plants in the projects it is developing. Advanced clean coal technologies such as integrated gasification combined cycle and pressurized fluidized bed combustion will be selected for independent power projects only in very specific circumstances. Advanced clean coal plants can be operated reliably and with superior performance, and specifically that their present estimated capital costs can be reduced substantially to a point where they are competitive with state-of-the-art pulverized coal technologies. (R.P.)

Forward Modeling of Reduced Power Spectra from Three-dimensional k-space

Science.gov (United States)

von Papen, Michael; Saur, Joachim

2015-06-01

We present results from a numerical forward model to evaluate one-dimensional reduced power spectral densities (PSDs) from arbitrary energy distributions in {\\boldsymbol{k}} -space. In this model, we can separately calculate the diagonal elements of the spectral tensor for incompressible axisymmetric turbulence with vanishing helicity. Given a critically balanced turbulent cascade with {{k}\\parallel }∼ k\\bot α and α \\lt 1, we explore the implications on the reduced PSD as a function of frequency. The spectra are obtained under the assumption of Taylor’s hypothesis. We further investigate the functional dependence of the spectral index κ on the field-to-flow angle θ between plasma flow and background magnetic field from MHD to electron kinetic scales. We show that critically balanced turbulence asymptotically develops toward θ-independent spectra with a slope corresponding to the perpendicular cascade. This occurs at a transition frequency {{f}2D}(L,α ,θ ), which is analytically estimated and depends on outer scale L, critical balance exponent α, and field-to-flow angle θ. We discuss anisotropic damping terms acting on the {\\boldsymbol{k}} -space distribution of energy and their effects on the PSD. Further, we show that the spectral anisotropies κ (θ ) as found by Horbury et al. and Chen et al. in the solar wind are in accordance with a damped critically balanced cascade of kinetic Alfvén waves. We also model power spectra obtained by Papen et al. in Saturn’s plasma sheet and find that the change of spectral indices inside 9 {{R}s} can be explained by damping on electron scales.

An objective decision model of power grid environmental protection based on environmental influence index and energy-saving and emission-reducing index

Science.gov (United States)

Feng, Jun-shu; Jin, Yan-ming; Hao, Wei-hua

2017-01-01

Based on modelling the environmental influence index of power transmission and transformation project and energy-saving and emission-reducing index of source-grid-load of power system, this paper establishes an objective decision model of power grid environmental protection, with constraints of power grid environmental protection objectives being legal and economical, and considering both positive and negative influences of grid on the environmental in all-life grid cycle. This model can be used to guide the programming work of power grid environmental protection. A numerical simulation of Jiangsu province’s power grid environmental protection objective decision model has been operated, and the results shows that the maximum goal of energy-saving and emission-reducing benefits would be reached firstly as investment increasing, and then the minimum goal of environmental influence.

Reviewing surveillance activities in nuclear power plants

International Nuclear Information System (INIS)

1989-03-01

This document provides guidance to Operational Safety Review Teams (OSARTs) for reviewing surveillance activities at a nuclear power plant. In addition, the document contains reference material to support the review of surveillance activities, to assist within the Technical Support area and to ensure consistency between individual reviews. Drafts of the document have already been used on several OSART missions and found to be useful. The document first considers the objectives of an excellent surveillance programme. Investigations to determine the quality of the surveillance programme are then discussed. The attributes of an excellent surveillance programme are listed. Advice follows on how to phrase questions so as to obtain an informative response on surveillance features. Finally, specific equipment is mentioned that should be considered when reviewing functional tests. Four annexes provide examples drawn from operating nuclear power plants. They were selected to supplement the main text of the document with the best international practices as found in OSART reviews. They should in no way limit the acceptance and development of alternative approaches that lead to equivalent or better results. Refs, figs and tabs

Managing server clusters on intermittent power

Directory of Open Access Journals (Sweden)

Navin Sharma

2015-12-01

Full Text Available Reducing the energy footprint of data centers continues to receive significant attention due to both its financial and environmental impact. There are numerous methods that limit the impact of both factors, such as expanding the use of renewable energy or participating in automated demand-response programs. To take advantage of these methods, servers and applications must gracefully handle intermittent constraints in their power supply. In this paper, we propose blinking—metered transitions between a high-power active state and a low-power inactive state—as the primary abstraction for conforming to intermittent power constraints. We design Blink, an application-independent hardware–software platform for developing and evaluating blinking applications, and define multiple types of blinking policies. We then use Blink to design both a blinking version of memcached (BlinkCache and a multimedia cache (GreenCache to demonstrate how application characteristics affect the design of blink-aware distributed applications. Our results show that for BlinkCache, a load-proportional blinking policy combines the advantages of both activation and synchronous blinking for realistic Zipf-like popularity distributions and wind/solar power signals by achieving near optimal hit rates (within 15% of an activation policy, while also providing fairer access to the cache (within 2% of a synchronous policy for equally popular objects. In contrast, for GreenCache, due to multimedia workload patterns, we find that a staggered load proportional blinking policy with replication of the first chunk of each video reduces the buffering time at all power levels, as compared to activation or load-proportional blinking policies.

Regulatory control of maintenance activities in Argentine nuclear power plants

International Nuclear Information System (INIS)

Calvo, J.C.; Caruso, G.

2000-01-01

The main maintenance objective is to assure that the safety features of structures, components and systems of nuclear power plants are kept as designed. Therefore, there is a direct relationship between safety and maintenance. Owing to the above mentioned, maintenance activities are considered a relevant regulatory issue for the Argentine Nuclear Regulatory Authority (ARN). This paper describes the regulatory control to maintenance activities of Argentine nuclear power plants. It also addresses essential elements for maintenance control, routine inspections, special inspections during planned outages, audits and license conditions and requirements. (author)

30.2 Digital PWM-driven AMOLED display on flex reducing static power consumption

NARCIS (Netherlands)

Genoe, J.; Obata, K.; Ameys, M.; Myny, K.; Ke, T.H.; Nag, M.; Steudel, S.; Schols, S.; Maas, J.; Tripathi, A.; Van Der Steen, J.-L.; Ellis, T.; Gelinck, G.H.; Heremans, P.

2014-01-01

The efficiency of small-molecule OLED devices increased substantially in recent years, creating opportunities for power-efficient displays, as only light is generated proportional to the subpixel intensity. However, current active matrix OLED (AMOLED) displays on foil do not validate this

Design of Passive Power Filter for Hybrid Series Active Power Filter using Estimation, Detection and Classification Method

Science.gov (United States)

Swain, Sushree Diptimayee; Ray, Pravat Kumar; Mohanty, K. B.

2016-06-01

This research paper discover the design of a shunt Passive Power Filter (PPF) in Hybrid Series Active Power Filter (HSAPF) that employs a novel analytic methodology which is superior than FFT analysis. This novel approach consists of the estimation, detection and classification of the signals. The proposed method is applied to estimate, detect and classify the power quality (PQ) disturbance such as harmonics. This proposed work deals with three methods: the harmonic detection through wavelet transform method, the harmonic estimation by Kalman Filter algorithm and harmonic classification by decision tree method. From different type of mother wavelets in wavelet transform method, the db8 is selected as suitable mother wavelet because of its potency on transient response and crouched oscillation at frequency domain. In harmonic compensation process, the detected harmonic is compensated through Hybrid Series Active Power Filter (HSAPF) based on Instantaneous Reactive Power Theory (IRPT). The efficacy of the proposed method is verified in MATLAB/SIMULINK domain and as well as with an experimental set up. The obtained results confirm the superiority of the proposed methodology than FFT analysis. This newly proposed PPF is used to make the conventional HSAPF more robust and stable.

Development of Real Time Implementation of 5/5 Rule based Fuzzy Logic Controller Shunt Active Power Filter for Power Quality Improvement

Science.gov (United States)

Puhan, Pratap Sekhar; Ray, Pravat Kumar; Panda, Gayadhar

2016-12-01

This paper presents the effectiveness of 5/5 Fuzzy rule implementation in Fuzzy Logic Controller conjunction with indirect control technique to enhance the power quality in single phase system, An indirect current controller in conjunction with Fuzzy Logic Controller is applied to the proposed shunt active power filter to estimate the peak reference current and capacitor voltage. Current Controller based pulse width modulation (CCPWM) is used to generate the switching signals of voltage source inverter. Various simulation results are presented to verify the good behaviour of the Shunt active Power Filter (SAPF) with proposed two levels Hysteresis Current Controller (HCC). For verification of Shunt Active Power Filter in real time, the proposed control algorithm has been implemented in laboratory developed setup in dSPACE platform.

Coordinated Control of Wind Turbine and Energy Storage System for Reducing Wind Power Fluctuation

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kim, Chunghun [Hanyang University; Chung, Chung Choo [Hanyang University

2017-11-13

This paper proposes a coordinated control of wind turbine and energy storage system (ESS). Because wind power (WP) is highly dependent on variable wind speed and could induce a severe stability problem to power system especially when the WP has high penetration level. To solve this problem, many power generation corporations or grid operators recently use the ESS. It has very quick response and good performance for reducing the impact of WP fluctuation but has high cost for its installation. Therefore, it is very important to design the control algorithm considering both ESS capacity and grid reliability. Thus, we propose the control algorithm to mitigate the WP fluctuation by using the coordinated control between wind turbine and ESS considering ESS state of charge (SoC) and the WP fluctuation. From deloaded control according to WP fluctuation and ESS SoC management, we can expect the ESS lifespan expansion and improved grid reliability. The effectiveness of the proposed method is validated in MATLAB/Simulink considering power system including both wind turbine generator and conventional generators which react to system frequency deviation.

Optimal testing input sets for reduced diagnosis time of nuclear power plant digital electronic circuits

International Nuclear Information System (INIS)

Kim, D.S.; Seong, P.H.

1994-01-01

This paper describes the optimal testing input sets required for the fault diagnosis of the nuclear power plant digital electronic circuits. With the complicated systems such as very large scale integration (VLSI), nuclear power plant (NPP), and aircraft, testing is the major factor of the maintenance of the system. Particularly, diagnosis time grows quickly with the complexity of the component. In this research, for reduce diagnosis time the authors derived the optimal testing sets that are the minimal testing sets required for detecting the failure and for locating of the failed component. For reduced diagnosis time, the technique presented by Hayes fits best for the approach to testing sets generation among many conventional methods. However, this method has the following disadvantages: (a) it considers only the simple network (b) it concerns only whether the system is in failed state or not and does not provide the way to locate the failed component. Therefore the authors have derived the optimal testing input sets that resolve these problems by Hayes while preserving its advantages. When they applied the optimal testing sets to the automatic fault diagnosis system (AFDS) which incorporates the advanced fault diagnosis method of artificial intelligence technique, they found that the fault diagnosis using the optimal testing sets makes testing the digital electronic circuits much faster than that using exhaustive testing input sets; when they applied them to test the Universal (UV) Card which is a nuclear power plant digital input/output solid state protection system card, they reduced the testing time up to about 100 times

Integrated services and maintenance in nuclear power plants

International Nuclear Information System (INIS)

Roos, Georg

2001-01-01

The general situation concerning services and nuclear power maintenance is reviewed following liberalization of Europa's power market. Issues relating to outsourcing maintenance services, effectiveness and reducing cost structure of maintenance are addressed on the cases of power markets in northern countries, Spain, Switzerland, Germany and Hungary. A special attention is paid on range of maintenance activity offered and performanced by Framatome. Ways of reducing costs in the field of maintenance as well as of reducing outage time are indicated. In conclusion, the following items are emphasized: - liberalization of Europe's power market in eastern Europe at its beginning; - in-house service in eastern Europe with numerous personnel; - Framatome ANP covers the entire range of maintenance competence; - consultance can be the first approach for a common co-operation

Communication Systems and Study Method for Active Distribution Power systems

DEFF Research Database (Denmark)

Wei, Mu; Chen, Zhe

Due to the involvement and evolvement of communication technologies in contemporary power systems, the applications of modern communication technologies in distribution power system are becoming increasingly important. In this paper, the International Organization for Standardization (ISO......) reference seven-layer model of communication systems, and the main communication technologies and protocols on each corresponding layer are introduced. Some newly developed communication techniques, like Ethernet, are discussed with reference to the possible applications in distributed power system....... The suitability of the communication technology to the distribution power system with active renewable energy based generation units is discussed. Subsequently the typical possible communication systems are studied by simulation. In this paper, a novel method of integrating communication system impact into power...

Costs of Reducing Greenhouse Gas Emissions: A Case Study of India’s Power Generation Sector

OpenAIRE

Manish Gupta

2006-01-01

If India were to participate in any international effort towards mitigating CO2 emissions, the power sector which is one of the largest emitters of CO2 in the country would be required to play a major role. In this context the study estimates the marginal abatement costs, which correspond to the costs incurred by the power plants to reduce one unit of CO2 from the current level. The study uses an output distance function approach and its duality with the revenue function to derive these costs...

Cortical activation during power grip task with pneumatic pressure gauge: an fMRI study

Science.gov (United States)

Mohamad, M.; Mardan, N. H.; Ismail, S. S.

2017-05-01

Aging is associated with a decline in cognitive and motor function. But, the relationships with motor performance are less well understood. In this study, functional magnetic resonance imaging (fMRI) was used to assess cortical activation in older adults. This study employed power grip task that utilised block paradigm consisted of alternate 30s rest and active. A visual cue was used to pace the hand grip movement that clenched a cylindrical rubber bulb connected with pressure pneumatic gauge that measure the pressure (Psi). The objective of this study is determined the brain areas activated during motor task and the correlation between percentage signal change of each motor area (BA 4 and 6) and hand grip pressure. Result showed there was a significant difference in mean percentage signal change in BA 4 and BA 6 in both hemispheres and negative correlation obtained in BA 4 and BA 6. These results indicate that a reduced ability in the motor networks contribute to age-related decline in motor performance.

A lot left over: Reducing CO2 emissions in the United States’ electric power sector through the use of natural gas

International Nuclear Information System (INIS)

Lafrancois, Becky A.

2012-01-01

As the leading contributor of greenhouse gas emissions, the electricity sector stands to be impacted by policies seeking to curtail emissions. Instead of increasing electricity from renewable resources or nuclear power facilities, an alternative approach to reducing emissions in the electric power sector is changing the dispatch order of fossil fuels. Important differences between fossil fuels, and in the technologies used to burn them, make it possible to substantially reduce emissions from the sector. On average, each gigawatt-year of electricity generation switched from coal to natural gas reduces CO 2 emissions by 59 percent. As a result of significant investments in natural gas fired power plants in the United States between 1998 and 2005, there is an opportunity for electricity producers to take advantage of underutilized capacity. This is the first study to closely examine the new capital additions and analyze the technical potential for reductions in emissions. The analysis finds that 188 GW of capacity may be available to replace coal-fired baseload electricity generation. Utilizing this excess gas-fired capacity will reduce the sector's CO 2 emissions by 23 to 42 percent and reduce overall U.S. CO 2 emissions between 9 percent and 17 percent. - Highlights: ► Utilizing recently built natural gas fired power plants can significantly reduce CO 2 emissions in the United States. ► CO 2 emissions from electricity production can be reduced by 23–42 percent. ► U.S. overall CO 2 emissions reduced by 9–17 percent.

SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

Energy Technology Data Exchange (ETDEWEB)

Onar, Omer C [ORNL; Tang, Lixin [ORNL; Chinthavali, Madhu Sudhan [ORNL; Campbell, Steven L [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC

2014-01-01

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

"While you still think, I already type": experienced social power reduces deliberation during e-mail communication.

Science.gov (United States)

Scholl, Annika; Sassenberg, Kai

2014-11-01

E-mail allows individuals to deliberate on their communication before sending it off. For instance, communication partners can easily take their time to ponder how best to frame a request before they actually send a message. Individuals at times strategically exploit this opportunity to deliberate in order to tailor messages to their communication partner, such as when communicating with a relatively more powerful person. As social power reduces concerns about impression management, we predicted that individuals deliberate more while composing e-mail messages under low (vs. high) power. This assumption was tested with well-established power priming. As such, we expected that experienced power in one context would diminish deliberation times during a subsequent e-mail communication. An experiment manipulating the experience of (low vs. high) power and measuring deliberation times during e-mail composition supported this hypothesis. The findings thus indicate how social power alters deliberation times. More importantly, the results show that individuals not only strategically deliberate during e-mail communication in line with their current situation, but also in line with their social standing in a previous situation (here, their experience of power).

Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

International Nuclear Information System (INIS)

Suarez Antola, R.

2011-01-01

One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems, during steady operation and during transients, to remain inside a certain bounded set of admissible states and state variations. Also, during transients, certain restrictions must be imposed on the time scale of evolution of the critical subsystem's state. A classification of the different solution types concerning their relation with the operational safety of the power plant is done by distributing the different solution types in relation with the exclusion region of the power-flow map. In the framework of an analytic or numerical modeling process of a boiling water reactor (BWR) power plant, this could imply first to find an suitable approximation to the solution manifold of the differential equations describing the stability behavior of this nonlinear system, and then a classification of the different solution types concerning their relation with the operational safety of the power plant, by distributing the different solution types in relation with the exclusion region of the power-flow map. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is used to exemplify the analytical approach developed here. The equation for excess void reactivity of this ROM is generalized. A nonlinear integral-differential equation in the logarithmic power is derived, including the generalized thermal-hydraulics feedback on the reactivity. Introducing a Krilov- Bogoliubov-Mitropolsky (KBM) ansatz with both amplitude and phase being slowly varying functions of time relative to the center period of oscillation, a coupled set of nonlinear ordinary differential equations for amplitude and phase

Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L.), J. oxycedrus (L.), J. phoenicea (L.) and Tetraclinis articulata (L.)

OpenAIRE

El Jemli, Meryem; Kamal, Rabie; Marmouzi, Ilias; Zerrouki, Asmae; Cherrah, Yahia; Alaoui, Katim

2016-01-01

Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic ...

IAEA activities in support of rising expectation to the role of nuclear power in developing countries

International Nuclear Information System (INIS)

Omoto, A.

2006-01-01

The Paris Conference N uclear energy for the 21st Century , which was held in March 2005 organized by the IAEA, is a strong indication of the interest in the role of nuclear power. At this conference, rising expectations were indicated as representatives from many countries expressed recognition of the potential of nuclear energy to meet their energy needs in a sustainable manner. A similar indication was recognized by the June 2004 Conference held by the IAEA in Obninsk, Russia, to celebrate 50 years of nuclear electricity production. Many developing countries that currently do not operate a nuclear power plant are expressing their view that nuclear power is an important option in their energy planning in order to alleviate energy price instability, to secure long-term energy supply and to achieve an energy mix that assures sustainability. India, China and other developing countries in Asia have ambitious nuclear power deployment programmes in order to support growing energy demand and per capita energy consumption. The IAEA has a mandate to secure the benefit of the peaceful use of nuclear technology for sustainability while working against the misuse of nuclear material. Under this mandate, many guidance documents have been prepared and various technical cooperation projects are carried out to support energy planning and infrastructure building to prepare for and to sustain nuclear power operation. Basically, the IAEA can provide support by four types of activities; a) helping the process in various stages, b) helping informed decision-making through providing analytical tools and publishing technical documents, and c) reducing institutional impediments through regional cooperation, multi-national arrangement and others; and d) supporting collaborative assessments and research toward development of nuclear plants and their applications. The paper describes the observed rising expectation and the IAEA's activities in response to the rising expectation of the role

The Method of Optimization of Hydropower Plant Performance for Use in Group Active Power Controller

Directory of Open Access Journals (Sweden)

Glazyrin G.V.

2017-04-01

Full Text Available The problem of optimization of hydropower plant performance is considered in this paper. A new method of calculation of optimal load-sharing is proposed. The method is based on application of incremental water flow curves representing relationship between the per unit increase of water flow and active power. The optimal load-sharing is obtained by solving the nonlinear equation governing the balance of total active power and the station power set point with the same specific increase of water flow for all turbines. Unlike traditional optimization techniques, the solution of the equation is obtained without taking into account unit safe operating zones. Instead, if calculated active power of a unit violates the permissible power range, load-sharing is recalculated for the remaining generating units. Thus, optimal load-sharing algorithm suitable for digital control systems is developed. The proposed algorithm is implemented in group active power controller in Novosibirsk hydropower plant. An analysis of operation of group active power controller proves that the application of the proposed method allows obtaining optimal load-sharing at each control step with sufficient precision.

Small Spacecraft Integrated Power System with Active Thermal Control

Data.gov (United States)

National Aeronautics and Space Administration — This project will develop an integrated power generation and energy storage system with an active thermal management system. Carbon fiber solar panels will contain...

Low-power priority Address-Encoder and Reset-Decoder data-driven readout for Monolithic Active Pixel Sensors for tracker system

International Nuclear Information System (INIS)

Yang, P.; Aglieri, G.; Cavicchioli, C.; Chalmet, P.L.; Chanlek, N.; Collu, A.; Gao, C.; Hillemanns, H.; Junique, A.; Kofarago, M.; Keil, M.; Kugathasan, T.; Kim, D.; Kim, J.; Lattuca, A.; Marin Tobon, C.A.; Marras, D.; Mager, M.; Martinengo, P.; Mazza, G.

2015-01-01

Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180 nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10 MHz with a matrix height of 15 mm. The energy consumed to read out one pixel is around 72 pJ. A scheme to boost the readout speed to 40 MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented

Low-power priority Address-Encoder and Reset-Decoder data-driven readout for Monolithic Active Pixel Sensors for tracker system

Energy Technology Data Exchange (ETDEWEB)

Yang, P., E-mail: yangping0710@126.com [Central China Normal University, Wuhan (China); Aglieri, G.; Cavicchioli, C. [CERN, 1210 Geneva 23 (Switzerland); Chalmet, P.L. [MIND, Archamps (France); Chanlek, N. [Suranaree University of Technology, Nakhon Ratchasima (Thailand); Collu, A. [University of Cagliari, Cagliari (Italy); INFN (Italy); Gao, C. [Central China Normal University, Wuhan (China); Hillemanns, H.; Junique, A. [CERN, 1210 Geneva 23 (Switzerland); Kofarago, M. [CERN, 1210 Geneva 23 (Switzerland); University of Utrecht, Utrecht (Netherlands); Keil, M.; Kugathasan, T. [CERN, 1210 Geneva 23 (Switzerland); Kim, D. [Dongguk and Yonsei University, Seoul (Korea, Republic of); Kim, J. [Pusan National University, Busan (Korea, Republic of); Lattuca, A. [University of Torino, Torino (Italy); INFN (Italy); Marin Tobon, C.A. [CERN, 1210 Geneva 23 (Switzerland); Marras, D. [University of Cagliari, Cagliari (Italy); INFN (Italy); Mager, M.; Martinengo, P. [CERN, 1210 Geneva 23 (Switzerland); Mazza, G. [University of Torino, Torino (Italy); INFN (Italy); and others

2015-06-11

Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180 nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10 MHz with a matrix height of 15 mm. The energy consumed to read out one pixel is around 72 pJ. A scheme to boost the readout speed to 40 MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented.

Low-power priority Address-Encoder and Reset-Decoder data-driven readout for Monolithic Active Pixel Sensors for tracker system

Science.gov (United States)

Yang, P.; Aglieri, G.; Cavicchioli, C.; Chalmet, P. L.; Chanlek, N.; Collu, A.; Gao, C.; Hillemanns, H.; Junique, A.; Kofarago, M.; Keil, M.; Kugathasan, T.; Kim, D.; Kim, J.; Lattuca, A.; Marin Tobon, C. A.; Marras, D.; Mager, M.; Martinengo, P.; Mazza, G.; Mugnier, H.; Musa, L.; Puggioni, C.; Rousset, J.; Reidt, F.; Riedler, P.; Snoeys, W.; Siddhanta, S.; Usai, G.; van Hoorne, J. W.; Yi, J.

2015-06-01

Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180 nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10 MHz with a matrix height of 15 mm. The energy consumed to read out one pixel is around 72 pJ. A scheme to boost the readout speed to 40 MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented.

Increasing ankle push-off work with a powered prosthesis does not necessarily reduce metabolic rate for transtibial amputees.

Science.gov (United States)

Quesada, Roberto E; Caputo, Joshua M; Collins, Steven H

2016-10-03

Amputees using passive ankle-foot prostheses tend to expend more metabolic energy during walking than non-amputees, and reducing this cost has been a central motivation for the development of active ankle-foot prostheses. Increased push-off work at the end of stance has been proposed as a way to reduce metabolic energy use, but the effects of push-off work have not been tested in isolation. In this experiment, participants with unilateral transtibial amputation (N=6) walked on a treadmill at a constant speed while wearing a powered prosthesis emulator. The prosthesis delivered different levels of ankle push-off work across conditions, ranging from the value for passive prostheses to double the value for non-amputee walking, while all other prosthesis mechanics were held constant. Participants completed six acclimation sessions prior to a data collection in which metabolic rate, kinematics, kinetics, muscle activity and user satisfaction were recorded. Metabolic rate was not affected by net prosthesis work rate (p=0.5; R 2 =0.007). Metabolic rate, gait mechanics and muscle activity varied widely across participants, but no participant had lower metabolic rate with higher levels of push-off work. User satisfaction was affected by push-off work (p=0.002), with participants preferring values of ankle push-off slightly higher than in non-amputee walking, possibly indicating other benefits. Restoring or augmenting ankle push-off work is not sufficient to improve energy economy for lower-limb amputees. Additional necessary conditions might include alternate timing or control, individualized tuning, or particular subject characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on the evaluation index of active power reserve

Science.gov (United States)

Guo, Xiaorui; Liu, Jiantao; Wang, Ke; Min, Lu

2018-01-01

Based on the role of active reserve at different time scales, divides the evaluation dimension of active reserve. Analysis the calculation principle of traditional reliability index such as probability of system safety, lack of power shortage and electricity shortage expectancy, and studies the applicability of these indicators to evaluate the reserve capacity on different dimensions. Resolves the evaluation index of active reserve capacity from the dimensions of time dimension, spatial dimension, system state, risk degree and economy, then construct evaluation index of active reserve capacity.

A novel control technique for active shunt power filters for aircraft applications

OpenAIRE

Lavopa, Elisabetta

2011-01-01

The More Electric Aircraft is a technological trend in modern aerospace industry to increasingly use electrical power on board the aircraft in place of mechanical, hydraulic and pneumatic power to drive aircraft subsystems. This brings major changes to the aircraft electrical system, increasing the complexity of the network topology together with stability and power quality issues. Shunt active power filters are a viable solution for power quality enhancement, in order to comply with the stan...

Continuous wave power scaling in high power broad area quantum cascade lasers

Science.gov (United States)

Suttinger, M.; Leshin, J.; Go, R.; Figueiredo, P.; Shu, H.; Lyakh, A.

2018-02-01

Experimental and model results for high power broad area quantum cascade lasers are presented. Continuous wave power scaling from 1.62 W to 2.34 W has been experimentally demonstrated for 3.15 mm-long, high reflection-coated 5.6 μm quantum cascade lasers with 15 stage active region for active region width increased from 10 μm to 20 μm. A semi-empirical model for broad area devices operating in continuous wave mode is presented. The model uses measured pulsed transparency current, injection efficiency, waveguide losses, and differential gain as input parameters. It also takes into account active region self-heating and sub-linearity of pulsed power vs current laser characteristic. The model predicts that an 11% improvement in maximum CW power and increased wall plug efficiency can be achieved from 3.15 mm x 25 μm devices with 21 stages of the same design but half doping in the active region. For a 16-stage design with a reduced stage thickness of 300Å, pulsed roll-over current density of 6 kA/cm2 , and InGaAs waveguide layers; optical power increase of 41% is projected. Finally, the model projects that power level can be increased to 4.5 W from 3.15 mm × 31 μm devices with the baseline configuration with T0 increased from 140 K for the present design to 250 K.

An Active Power Filter Based on a Three-Level Inverter and 3D-SVPWM for Selective Harmonic and Reactive Compensation

Directory of Open Access Journals (Sweden)

José Luis Monroy-Morales

2017-03-01

Full Text Available Active Power Filters (APFs have been used for reducing waveform distortion and improving power quality. However, this function can be improved by means of a selective harmonic compensation. Since an APF has rating restrictions, it is convenient to have the option of selecting an individual or a set of particular harmonics in order to compensate and apply the total APF capabilities to eliminate these harmonics, in particular those with a greater impact on the Total Harmonic Distortion (THD. This paper presents the development of a new APF prototype based on a three-phase three-level Neutral Point Clamped (NPC inverter with selective harmonic compensation capabilities and reactive power compensation. The selective harmonic compensation approach uses several Synchronous Rotating Frames (SRF, to detect and control individual or a set of harmonics using d and q variables. The APF includes a Three-Dimensional Space Vector Modulator (3D-SVPWM in order to generate the compensation currents. Because of its multilevel topology, the proposed active power filter can be used in diverse power quality applications at sub-transmission and distribution voltage levels. Simulation and experimental results are shown to validate the proposed solution and assess the prototype performance in different scenarios.

Requirements Specication for Ampliers and Power Supplies in Active Loudspeakers

DEFF Research Database (Denmark)

Schneider, Henrik; Jensen, Lasse Crone; Petersen, Lars Press

2014-01-01

This work aims to provide designers with a method to develop a requirements specication for power supplies and ampliers in active loudspeakers. The motivation is to avoid over-sizing and unnecessary cost. A realistic estimation of the power supplied during playback of audio in a given loudspeaker...... is obtained by considering a wide range of audio source material, loudness normalization of the source material, crossover ltering, driver characteristics as well as a perceived maximum loudness/volume level. The results from analysing a sub-woofer and a woofer reveals the peak power, peak voltage, peak...... current and apparent power - thus providing a solid foundation for a requirement specication....

INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS

NARCIS (Netherlands)

Bartoloni, Fernando Heering; Monteiro Leite Ciscato, Luiz Francisco; Augusto, Felipe Alberto; Baader, Wilhelm Josef

2010-01-01

INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS. Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron

Lipid reducing activity and toxicity profiles of a library of polyphenol derivatives.

Science.gov (United States)

Urbatzka, Ralph; Freitas, Sara; Palmeira, Andreia; Almeida, Tiago; Moreira, João; Azevedo, Carlos; Afonso, Carlos; Correia-da-Silva, Marta; Sousa, Emilia; Pinto, Madalena; Vasconcelos, Vitor

2018-05-10

Obesity is an increasing epidemic worldwide and novel treatments are urgently needed. Polyphenols are natural compounds derived from plants, which are known in particular for their antioxidant properties. However, some polyphenols were described to possess anti-obesity activities in vitro and in vivo. In this study, we aimed to screen a library of 85 polyphenol derivatives for their lipid reducing activity and toxicity. Compounds were analyzed at 5 μM with the zebrafish Nile red fluorescence fat metabolism assay and for general toxicity in vivo. To improve the safety profile, compounds were screened at 50 μM in murine preadipocytes in vitro for cytotoxicity. Obtained activity data were used to create a 2D-QSAR (quantitative structure activity relationship) model. 38 polyphenols showed strong lipid reducing activity. Toxicity analysis revealed that 18 of them did not show any toxicity in vitro or in vivo. QSAR analysis revealed the importance of the number of rings, fractional partial positively charged surface area, relative positive charge, relative number of oxygen atoms, and partial negative surface area for lipid-reducing activity. The five most potent compounds with EC 50 values in the nanomolar range for lipid reducing activity and without any toxic effects are strong candidates for future research and development into anti-obesity drugs. Molecular profiling for fasn, sirt1, mtp and ppary revealed one compound that reduced significantly fasn mRNA expression. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

IAEA activities in nuclear power plant personnel training and qualification

International Nuclear Information System (INIS)

Mautner-Markhof, F.

1993-01-01

Training to achieve and maintain the qualification and competence of nuclear power personnel is essential for safe and economic nuclear power. Technical Cooperation Meeting on Training-Related Activities for Nuclear Power Plant (NPP) Personnel in the countries of Central and Eastern Europe (CEEC) and of the former Soviet Union (FSU) has as its main objective the identification, through information exchange and discussion, of possible Technical Cooperation (TC) projects to assist Member States in meeting NPP personnel training needs and priorities, including the enhancing of training capabilities

Validation of Power Requirement Model for Active Loudspeakers

DEFF Research Database (Denmark)

Schneider, Henrik; Madsen, Anders Normann; Bjerregaard, Ruben

2015-01-01

. There are however many advantages that could be harvested from such knowledge like size, cost and efficiency improvements. In this paper a recently proposed power requirement model for active loudspeakers is experimentally validated and the model is expanded to include the closed and vented type enclosures...

The Electromechanical Low-Power Active Suspension: Modeling, Control, and Prototype Testing

NARCIS (Netherlands)

Evers, W.J.E.; Teerhuis, A.P.; Knaap, van der A.C.M.; Besselink, I.J.M.; Nijmeijer, H.

2011-01-01

The high energy consumption of market-ready active suspension systems is the limiting factor in the competition with semi-active devices. The variable geometry active suspension is an alternative with a significantly lower power consumption. However, previous designs suffer from packaging problems,

The electromechanical low-power active suspension: modeling, control, and prototype testing

NARCIS (Netherlands)

Evers, W.J.; Teerhuis, A.P.; Knaap, A. van der; Besselink, I.; Nijmeijer, H.

2011-01-01

The high energy consumption of market-ready active suspension systems is the limiting factor in the competition with semi-active devices. The variable geometry active suspension is an alternative with a significantly lower power consumption. However, previous designs suffer from packaging problems,

Low-activation structural ceramic composites for fusion power reactors: materials development and main design issues

International Nuclear Information System (INIS)

Perez, A.S.; Le Bars, N.; Giancarli, L.; Proust, E.; Salavy, J.F.

1994-01-01

Development of advanced Low-Activation Materials (LAMs) with favourable short-term activation characteristics is discussed, for the use as structural materials in a fusion power reactor (in order to reduce the risk associated with a major accident, in particular those related with radio-isotopes release in the environment), and to try to approach the concept of an inherently safe reactor. LA Ceramics Composites (LACCs) are the most promising LAMs because of their relatively good thermo-mechanical properties. At present, SiC/SiC composite is the only LACC considered by the fusion community, and therefore is the one having the most complete data base. The preliminary design of a breeding blanket using SiC/SiC as structural material indicated that significant improvement of its thermal conductivity is required. (author) 11 refs.; 3 figs

Active current control in wind power plants during grid faults

DEFF Research Database (Denmark)

Martinez, Jorge; Kjær, Phillip C.; Rodriguez, Pedro

2010-01-01

Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements......, wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe...... faults, causing low voltages at the point of common coupling. As a consequence, a new wind turbine current controller for operation during faults is proposed. It is shown that to achieve the maximum transfer of reactive current at the point of common coupling, a strategy for optimal setting of the active...

Wind power plant system services

DEFF Research Database (Denmark)

Basit, Abdul; Altin, Müfit

Traditionally, conventional power plants have the task to support the power system, by supplying power balancing services. These services are required by the power system operators in order to secure a safe and reliable operation of the power system. However, as in the future the wind power...... is going more and more to replace conventional power plants, the sources of conventional reserve available to the system will be reduced and fewer conventional plants will be available on-line to share the regulation burden. The reliable operation of highly wind power integrated power system might...... then beat risk unless the wind power plants (WPPs) are able to support and participate in power balancing services. The objective of this PhD project is to develop and analyse control strategies which can increase the WPPs capability to provide system services, such as active power balancing control...

Nuclear Power Plant Control and Instrumentation activities in Finland

International Nuclear Information System (INIS)

Haapanen, P.; Wahlstroem, B.

1990-01-01

Finland has achieved some remarkable achievements in nuclear power production. Existing four plants have some of the best operating records in the world - high capacity factors, low occupational doses and short refuelling outages. Although public opinion was strongly turned against nuclear power after Chernobyl accident, and no decisions for new nuclear plants can be made before next elections in 1991, the nuclear option is still open. Utility companies are maintaining readiness to start new construction immediately after a positive political decision is made. One important component of the good operation history of the Finnish nuclear power plants is connected to the continuous research, development, modification and upgrading work, which is proceeding in Finland. In the following a short description is given on recent activities related to the I and C-systems of the nuclear power plants. (author). 2 tabs

Active control of radiated sound power from a baffled, rectangular panel

DEFF Research Database (Denmark)

Mørkholt, Jakob

1996-01-01

with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained over......Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... a broad frequency range using few piezoceramic actuators, provided that an accurate estimate of the sound power is available for minimisation....

Sensitivity study of reduced models of the activated sludge process ...

African Journals Online (AJOL)

2009-08-07

Aug 7, 2009 ... Sensitivity study of reduced models of the activated sludge process, for the purposes of parameter estimation and process optimisation: Benchmark process with ASM1 and UCT reduced biological models. S du Plessis and R Tzoneva*. Department of Electrical Engineering, Cape Peninsula University of ...

Harmonic Analysis and Active Filtering in Offshore Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay Kumar; Freijedo Fernandez, Francisco Daniel; Guerrero, Josep M.

2015-01-01

Due to presence of long high voltage cable networks, and power transformers for the grid connection, the offshore wind power plants (OWPPs) are susceptible to harmonic distortion and resonances. The grid connection of OWPP should not cause the harmonic distortion beyond the permissible limits...... at the point of common coupling (PCC). The resonance conditions should be avoided in all cases. This paper describes the harmonic analysis techniques applied on an OWPP network model. A method is proposed to estimate the harmonic current compensation from a shunt-connected active power filter to mitigate...

Brushless power generating system having reduced conducted emissions in output power

International Nuclear Information System (INIS)

Walton, D.N.; Dolan, C.F.; Shah, M.J.

1991-01-01

This patent describes a brushless electrical power generating system. It comprises an exciter for producing alternating current from an exciter rotor; a rectifier mounted for rotation with the rotor for producing a rectified control current from the alternating current; a common mode inductor, coupled to the rectifier, for cancelling common mode noise components within the rectified control current; and a main generator, having a rotating field winding mounted on a main generator rotor excited by the control current and producing an alternating current power output from a stator

Power Factor Improvement Using Automatic Power Factor Compensation (APFC Device for Medical Industries in Malaysia

Directory of Open Access Journals (Sweden)

Zaidi Maryam Nabihah

2018-01-01

Full Text Available This paper present the project designed to correcting power factor for medical industries in Malaysia automatically. Which with hope to make the cost and energy usage efficient, because the energy source are depleting due to increase in population. Power factor is the ratio of real power and apparent power. This definition is mathematically represented as kW/kVA where kW is active power and kVA is apparent power (active + reactive. Reactive power is the non-working power generated by the magnetic and inductive load to generate magnetic flux. The increase in reactive power increase the apparent power so the power factor will decrease. Low pF will cause the industry to meet high demand thus making it less efficient. The main aim of this project is to increasing the current power factor of medical industries from 0.85 to 0.90. Power factor compensation contribute to reduction in current-dependent losses and increase energy efficiency while expanding the reliability of planning for future energy network. As technology develops, the gradual cost and efficiency penalty should reduce. Therefore, automatic power factor compensation device should become cost-effective and smaller device over time. That is the reason this project is using programmable device as it is a miniature architecture device.

Blockade of mast cell activation reduces cutaneous scar formation.

Directory of Open Access Journals (Sweden)

Lin Chen

Full Text Available Damage to the skin initiates a cascade of well-orchestrated events that ultimately leads to repair of the wound. The inflammatory response is key to wound healing both through preventing infection and stimulating proliferation and remodeling of the skin. Mast cells within the tissue are one of the first immune cells to respond to trauma, and upon activation they release pro-inflammatory molecules to initiate recruitment of leukocytes and promote a vascular response in the tissue. Additionally, mast cells stimulate collagen synthesis by dermal fibroblasts, suggesting they may also influence scar formation. To examine the contribution of mast cells in tissue repair, we determined the effects the mast cell inhibitor, disodium cromoglycate (DSCG, on several parameters of dermal repair including, inflammation, re-epithelialization, collagen fiber organization, collagen ultrastructure, scar width and wound breaking strength. Mice treated with DSCG had significantly reduced levels of the inflammatory cytokines IL-1α, IL-1β, and CXCL1. Although DSCG treatment reduced the production of inflammatory mediators, the rate of re-epithelialization was not affected. Compared to control, inhibition of mast cell activity caused a significant decrease in scar width along with accelerated collagen re-organization. Despite the reduced scar width, DSCG treatment did not affect the breaking strength of the healed tissue. Tryptase β1 exclusively produced by mast cells was found to increase significantly in the course of wound healing. However, DSCG treatment did not change its level in the wounds. These results indicate that blockade of mast cell activation reduces scar formation and inflammation without further weakening the healed wound.

PA activity by using nuclear power plant safety demonstration and analysis

International Nuclear Information System (INIS)

Tsuchiya, Mitsuo; Kamimae, Rie

1999-01-01

INS/NUPEC presents one of Public acceptance (PA) methods for nuclear power in Japan, 'PA activity by using Nuclear Power Plant Safety Demonstration and Analysis', by using one of videos which is explained and analyzed accident events (Loss of Coolant Accident). Safety regulations of The National Government are strictly implemented in licensing at each of basic design and detailed design. To support safety regulation activities conducted by the National Government, INS/NLTPEC continuously implement Safety demonstration and analysis. With safety demonstration and analysis, made by assuming some abnormal conditions, what impacts could be produced by the assumed conditions are forecast based on specific design data on a given nuclear power plants. When analysis results compared with relevant decision criteria, the safety of nuclear power plants is confirmed. The decision criteria are designed to help judge if or not safety design of nuclear power plants is properly made. The decision criteria are set in the safety examination guidelines by taking sufficient safety allowance based on the latest technical knowledge obtained from a wide range of tests and safety studies. Safety demonstration and analysis is made by taking the procedure which are summarized in this presentation. In Japan, various PA (Public Acceptance) pamphlets and videos on nuclear energy have been published. But many of them focused on such topics as necessity or importance of nuclear energy, basic principles of nuclear power generation, etc., and a few described safety evaluation particularly of abnormal and accident events in accordance with the regulatory requirements. In this background, INS/NUPEC has been making efforts to prepare PA pamphlets and videos to explain the safety of nuclear power plants, to be simple and concrete enough, using various analytical computations for abnormal and accident events. In results, PA activity of INS/NUPEC is evaluated highly by the people

Nanogenerators for Self-Powered Gas Sensing

Science.gov (United States)

Wen, Zhen; Shen, Qingqing; Sun, Xuhui

2017-10-01

Looking toward world technology trends over the next few decades, self-powered sensing networks are a key field of technological and economic driver for global industries. Since 2006, Zhong Lin Wang's group has proposed a novel concept of nanogenerators (NGs), including piezoelectric nanogenerator and triboelectric nanogenerator, which could convert a mechanical trigger into an electric output. Considering motion ubiquitously exists in the surrounding environment and for any most common materials used every day, NGs could be inherently served as an energy source for our daily increasing requirements or as one of self-powered environmental sensors. In this regard, by coupling the piezoelectric or triboelectric properties with semiconducting gas sensing characterization, a new research field of self-powered gas sensing has been proposed. Recent works have shown promising concept to realize NG-based self-powered gas sensors that are capable of detecting gas environment without the need of external power sources to activate the gas sensors or to actively generate a readout signal. Compared with conventional sensors, these self-powered gas sensors keep the approximate performance. Meanwhile, these sensors drastically reduce power consumption and additionally reduce the required space for integration, which are significantly suitable for the wearable devices. This paper gives a brief summary about the establishment and latest progress in the fundamental principle, updated progress and potential applications of NG-based self-powered gas sensing system. The development trend in this field is envisaged, and the basic configurations are also introduced.

Nuclear power development and nuclear data activities in Malaysia

International Nuclear Information System (INIS)

Gui Ah Auu

1999-01-01

In this paper, research activities on nuclear power requirement carried out jointly by MINT and other organizations are described. Also discussed are activities on neutronics such as TRIGA reactor fuel management, storage pool criticality, and reactor fuel transfer cask calculations. In addition, recent work on radiation transport activities in MINT such as skyshine and photon phantom dose calculations using the MCNP and MRIPP computer codes are presented. Finally, nuclear data measurement works by researchers in Malaysian universities are described. (author)

Nuclear power development and nuclear data activities in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Gui Ah Auu [Malaysian Institute for Nuclear Technology Research, Ministry of Science, Technology and the Environment, Selangor (Malaysia)

1999-03-01

In this paper, research activities on nuclear power requirement carried out jointly by MINT and other organizations are described. Also discussed are activities on neutronics such as TRIGA reactor fuel management, storage pool criticality, and reactor fuel transfer cask calculations. In addition, recent work on radiation transport activities in MINT such as skyshine and photon phantom dose calculations using the MCNP and MRIPP computer codes are presented. Finally, nuclear data measurement works by researchers in Malaysian universities are described. (author)

Design and implementation of predictive filtering system for current reference generation of active power filter

Energy Technology Data Exchange (ETDEWEB)

Kilic, Tomislav; Milun, Stanko; Petrovic, Goran [FESB University of Split, Faculty of Electrical Engineering, Machine Engineering and Naval Architecture, R. Boskovica bb, 21000, Split (Croatia)

2007-02-15

The shunt active power filters are used to attenuate the harmonic currents in power systems by injecting equal but opposite compensating currents. Successful control of the active filters requires an accurate current reference. In this paper the current reference determination based on predictive filtering structure is presented. Current reference was obtained by taking the difference of load current and its fundamental harmonic. For fundamental harmonic determination with no time delay a combination of digital predictive filter and low pass filter is used. The proposed method was implemented on a laboratory prototype of a three-phase active power filter. The algorithm for current reference determination was adapted and implemented on DSP controller. Simulation and experimental results show that the active power filter with implemented predictive filtering structure gives satisfactory performance in power system harmonic attenuation. (author)

High power density carbonate fuel cell

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

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

A High Power Density Integrated Charger for Electric Vehicles with Active Ripple Compensation

Directory of Open Access Journals (Sweden)

Liwen Pan

2015-01-01

Full Text Available This paper suggests a high power density on-board integrated charger with active ripple compensation circuit for electric vehicles. To obtain a high power density and high efficiency, silicon carbide devices are reported to meet the requirement of high-switching-frequency operation. An integrated bidirectional converter is proposed to function as AC/DC battery charger and to transfer energy between battery pack and motor drive of the traction system. In addition, the conventional H-bridge circuit suffers from ripple power pulsating at second-order line frequency, and a scheme of active ripple compensation circuit has been explored to solve this second-order ripple problem, in which a pair of power switches shared traction mode, a ripple energy storage capacitor, and an energy transfer inductor. Simulation results in MATLAB/Simulink validated the eligibility of the proposed topology. The integrated charger can work as a 70 kW motor drive circuit or a converter with an active ripple compensation circuit for 3 kW charging the battery. The impact of the proposed topology and control strategy on the integrated charger power losses, efficiency, power density, and thermal performance has also been analysed and simulated.

Wind, Wave, and Tidal Energy Without Power Conditioning

Science.gov (United States)

Jones, Jack A.

2013-01-01

Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time. Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning. A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines

Thin disk laser with unstable resonator and reduced output coupler

Science.gov (United States)

Gavili, Anwar; Shayganmanesh, Mahdi

2018-05-01

In this paper, feasibility of using unstable resonator with reduced output coupling in a thin disk laser is studied theoretically. Unstable resonator is modeled by wave-optics using Collins integral and iterative method. An Yb:YAG crystal with 250 micron thickness is considered as a quasi-three level active medium and modeled by solving rate equations of energy levels populations. The amplification of laser beam in the active medium is calculated based on the Beer-Lambert law and Rigrod method. Using generalized beam parameters method, laser beam parameters like, width, divergence, M2 factor, output power as well as near and far-field beam profiles are calculated for unstable resonator. It is demonstrated that for thin disk laser (with single disk) in spite of the low thickness of the disk which leads to low gain factor, it is possible to use unstable resonator (with reduced output coupling) and achieve good output power with appropriate beam quality. Also, the behavior of output power and beam quality versus equivalent Fresnel number is investigated and optimized value of output coupling for maximum output power is achieved.

Power pulsing of the CMOS sensor Mimosa 26

International Nuclear Information System (INIS)

Kuprash, Oleg

2013-01-01

Mimosa 26 is a monolithic active pixel sensor developed by IPHC (Strasbourg) and IRFU (Saclay) as a prototype for the ILC vertex detector studies. The resolution requirements for the ILC tracking detector are very extreme, demanding very low material in the detector, thus only air cooling can be considered. Power consumption has to be reduced as far as possible. The beam structure of the ILC allows the possibility of power pulsing: only for about the 1 ms long bunch train full power is required, and during the 199 ms long pauses between the bunch trains the power can be reduced to a minimum. Not being adapted for the power pulsing, the sensor shows in laboratory tests a good performance under power pulsing. The power pulsing allows to significantly reduce the heating of the chip and divides power consumption approximately by a factor of 6. In this report a summary of power pulsing studies using the digital readout of Mimosa 26 is given. -- Highlights: • First power pulsing studies using digital readout of Mimosa 26 CMOS sensor were done. • Fake hit rates under power pulsing conditions and under normal conditions were compared. • The measurements demonstrate that there is so far no showstopper to operate CMOS pixel sensors in power pulsing mode

Harmonic Active Filtering and Impedance-based Stability Analysis in Offshore Wind Power Plants

DEFF Research Database (Denmark)

Dhua, Debasish; Yang, Guangya; Zhang, Zhe

2017-01-01

installation and provides effectively similar functionality as passive filters. This work is focused on harmonic propagation studies in wind power plants, power quality evaluation at the point of connection and harmonic mitigation by active filtering. Finally, an impedance-based stability analysis......Nowadays, to eliminate harmonics injected by the wind turbines in offshore wind power plants there is a need to install passive filters. Moreover, the passive filters are not adaptive to harmonic profile changes due to topology changes, grid loading etc. Therefore, active filters in wind turbines...... are proposed as a flexible harmonic mitigation measure. The motivation of this study is to explore the possibility of embedding active filtering in wind turbine grid-side converters without having to change the system electrical infrastructure. The active filtering method can prevent additional equipment...

On power consumption issues in FIR filters with application to communication receivers: complexity, word length, and switching activity

Energy Technology Data Exchange (ETDEWEB)

Havashki, Asghar

2009-10-15

channel estimation must be upheld, in particular at medium-to-high Channel Signal to Noise Ratios (CSNR). Furthermore, reducing the power consumption through word-length optimization, when realizing such estimators, is an attractive approach. Due to the characteristics of the input signal to such estimators, a special treatment of channel estimation error due to quantization of estimator filter coefficients is needed. In this thesis we investigate the impact of finite coefficient word length on channel estimator performance. A theoretical analysis of the increase in channel estimation error due to quantization of estimator coefficients is performed, and the behavior of this error in different fading environments and for different filter orders is studied. The power consumed in a channel estimator is also influenced by the switching activity in the input signal of the estimator. Characterizing the switching activity in the input signal, including how this activity changes in different environments, e.g., in the presence of noise, is a subject of the work performed in this thesis. In this study we give an expression for direct calculation of the correlation coefficient for the most significant bit in a signal, using the word-level correlation coefficient. We also derive expressions for accurately calculating the variance and word-level correlation coefficient for a correlated signal, when an additional noise of a given variance is added to the signal. This can be used to estimate the bit-level switching activity in a signal in the presence of noise, based on the Dual Bit Type (DBT) method. The impact the additional noise has on the switching activity of a correlated signal has also been studied. These results make it possible for a designer to model the actual input switching activity in different real life noisy environments, enabling realistic power consumption estimation. A study on switching activity reduction in estimator filters using a coefficient reordering method

Performance Improvement of Shunt Active Power Filter With Dual Parallel Topology

DEFF Research Database (Denmark)

Asiminoaei, Lucian; Lascu, Cristian; Blaabjerg, Frede

2007-01-01

loop and the other is in a feedforward loop for harmonic compensation. Thus, both active power filters bring their own characteristic advantages, i.e., the feedback filter improves the steady-state performance of the harmonic mitigation and the feedforward filter improves the dynamic response. Another......This paper describes the control and parallel operation of two active power filters (APFs). Possible parallel operation situations of two APFs are investigated, and then the proposed topology is analyzed. The filters are coupled in a combined topology in which one filter is connected in a feedback...

Active learning reduces annotation time for clinical concept extraction.

Science.gov (United States)

Kholghi, Mahnoosh; Sitbon, Laurianne; Zuccon, Guido; Nguyen, Anthony

2017-10-01

To investigate: (1) the annotation time savings by various active learning query strategies compared to supervised learning and a random sampling baseline, and (2) the benefits of active learning-assisted pre-annotations in accelerating the manual annotation process compared to de novo annotation. There are 73 and 120 discharge summary reports provided by Beth Israel institute in the train and test sets of the concept extraction task in the i2b2/VA 2010 challenge, respectively. The 73 reports were used in user study experiments for manual annotation. First, all sequences within the 73 reports were manually annotated from scratch. Next, active learning models were built to generate pre-annotations for the sequences selected by a query strategy. The annotation/reviewing time per sequence was recorded. The 120 test reports were used to measure the effectiveness of the active learning models. When annotating from scratch, active learning reduced the annotation time up to 35% and 28% compared to a fully supervised approach and a random sampling baseline, respectively. Reviewing active learning-assisted pre-annotations resulted in 20% further reduction of the annotation time when compared to de novo annotation. The number of concepts that require manual annotation is a good indicator of the annotation time for various active learning approaches as demonstrated by high correlation between time rate and concept annotation rate. Active learning has a key role in reducing the time required to manually annotate domain concepts from clinical free text, either when annotating from scratch or reviewing active learning-assisted pre-annotations. Copyright © 2017 Elsevier B.V. All rights reserved.

Indirect Control of a low power Single-Phase Active Power Filter

Directory of Open Access Journals (Sweden)

SILVIU EPURE

2010-12-01

Full Text Available This paper deals with a low power, single phase active filter used to compensate nonlinear loads. The filter uses the indirect control method and it is based on a particular connection between filter, polluting load and grid to avoid timeconsuming mathematic operations or signal processing computations and assures good rejection of harmonic currents injected by the nonlinear load into the grid. A scale model was first simulated in Simulink and then physically implemented. The paper presents simulation and experimental results, and highlight problems encountered during experiments.

Wireless Power Transfer to a Microaerial Vehicle with a Microwave Active Phased Array

Directory of Open Access Journals (Sweden)

Shotaro Nako

2014-01-01

Full Text Available A wireless power transfer system using a microwave active phased array was developed. In the system, power is transferred to a circling microaerial vehicle (MAV by a microwave beam of 5.8 GHz, which is formed and directed to the MAV using an active phased array antenna. The MAV is expected to support observation of areas that humans cannot reach. The power beam is formed by the phased array with eight antenna elements. Input power is about 5.6 W. The peak power density at 1,500 mm altitude was 2.63 mW/cm2. The power is sent to a circling MAV. Therefore, the transfer beam should be polarized circularly to achieve a constant power supply independent of its yaw angle. To minimize the polarization loss, a sequentially routed antenna (SRA was applied to the transmitter antenna. Results show that the axial ratio of 0.440 dB was accomplished and that power fluctuation was kept below 1%.

Two-step activation of paper batteries for high power generation: design and fabrication of biofluid- and water-activated paper batteries

Science.gov (United States)

Lee, Ki Bang

2006-11-01

Two-step activation of paper batteries has been successfully demonstrated to provide quick activation and to supply high power to credit card-sized biosystems on a plastic chip. A stack of a magnesium layer (an anode), a fluid guide (absorbent paper), a highly doped filter paper with copper chloride (a cathode) and a copper layer as a current collector is laminated between two transparent plastic films into a high power biofluid- and water-activated battery. The battery is activated by two-step activation: (1) after placing a drop of biofluid/water-based solution on the fluid inlet, the surface tension first drives the fluid to soak the fluid guide; (2) the fluid in the fluid guide then penetrates into the heavily doped filter paper with copper chloride to start the battery reaction. The fabricated half credit card-sized battery was activated by saliva, urine and tap water and delivered a maximum voltage of 1.56 V within 10 s after activation and a maximum power of 15.6 mW. When 10 kΩ and 1 KΩ loads are used, the service time with water, urine and saliva is measured as more than 2 h. An in-series battery of 3 V has been successfully tested to power two LEDs (light emitting diodes) and an electric driving circuit. As such, this high power paper battery could be integrated with on-demand credit card-sized biosystems such as healthcare test kits, biochips, lab-on-a-chip, DNA chips, protein chips or even test chips for water quality checking or chemical checking.

The Importance of Vigorous-Intensity Leisure-Time Physical Activity in Reducing Cardiovascular Disease Mortality Risk in the Obese.

Science.gov (United States)

O'Donovan, Gary; Stamatakis, Emmanuel; Stensel, David J; Hamer, Mark

2018-03-02

To investigate the role of vigorous-intensity leisure-time physical activity in reducing cardiovascular disease (CVD) mortality risk in the obese. Trained interviewers assessed physical activity and body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) in 59,005 adult participants (mean ± SD age, 57±12 years; 46.5% male) in 2 household-based surveillance studies: Health Survey for England and Scottish Health Survey. Mortality was ascertained from death certificates. Data were collected from January 1, 1994, through March 31, 2011. Cox proportional hazards models were adjusted for age, sex, smoking habit, total physical activity, long-standing illness, prevalent CVD, and occupation. There were 2302 CVD deaths during 532,251 person-years of follow-up (mean ± SD, 9±4 years). A total of 15,002 (25%) participants were categorized as obese (BMI ≥30). Leisure-time physical activity was inversely associated and BMI was positively associated with CVD mortality. Compared with those who reported meeting physical activity guidelines including some vigorous-intensity physical activity and who had a normal BMI (18.5-24.9) (reference group), the CVD mortality hazard ratio was not significantly different in the obese who also reported meeting physical activity guidelines including some vigorous-intensity physical activities (1.25; 95% CI, 0.50-3.12). Compared with the reference group, the CVD mortality hazard ratio was more than 2-fold in the obese who reported meeting physical activity guidelines, including only moderate-intensity physical activities (2.52; 95% CI, 1.15-2.53). This large, statistically powerful study suggests that vigorous-intensity leisure-time physical activity is important in reducing CVD mortality risk in the obese. Copyright © 2018 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Active Power Deficit Estimation in Presence of Renewable Energy Sources

DEFF Research Database (Denmark)

Hoseinzadeh, Bakhtyar; Silva, Filipe Miguel Faria da; Bak, Claus Leth

2015-01-01

The inertia of the power system is reduced in the presence of Renewable Energy Sources (RESs) due to their low or even no contribution in the inertial response as it is inherently available in the Synchronous Machines (SMs). The total inertia of the grid becomes unknown or at least uncertain...

Cortical activation during power grip task with pneumatic pressure gauge: an fMRI study

International Nuclear Information System (INIS)

Mohamad, M; Ismail, S S; Mardan, N H

2017-01-01

Aging is associated with a decline in cognitive and motor function. But, the relationships with motor performance are less well understood. In this study, functional magnetic resonance imaging (fMRI) was used to assess cortical activation in older adults. This study employed power grip task that utilised block paradigm consisted of alternate 30s rest and active. A visual cue was used to pace the hand grip movement that clenched a cylindrical rubber bulb connected with pressure pneumatic gauge that measure the pressure (Psi). The objective of this study is determined the brain areas activated during motor task and the correlation between percentage signal change of each motor area (BA 4 and 6) and hand grip pressure. Result showed there was a significant difference in mean percentage signal change in BA 4 and BA 6 in both hemispheres and negative correlation obtained in BA 4 and BA 6. These results indicate that a reduced ability in the motor networks contribute to age-related decline in motor performance. (paper)

Nuclear Power and Safety Division activity

International Nuclear Information System (INIS)

Pazdera, F.

1991-01-01

History of the Division is briefly described. Present research is centered on reliability analyses and thermal hydraulic analyses of transients and accidents. Some results of the safety analyses have been applied at nuclear power plants. A characterization is presented of computer codes for analyzing the behavior of fuel in normal and accident conditions. Research activities in the field of water chemistry and corrosion are oriented to the corrosion process at high temperatures and high pressures, and the related mass and radioactivity transfer; the effect of some chemical processes on primary coolant circuit materials; optimization of PWR filtration systems; and the development of the requisite monitoring instrumentation. A computerized operator support system has been developed, and at present it is tested at the Dukovany nuclear power plant. A program of nuclear fuel cycle strategy and economy has been worked out for nuclear fuel performance evaluation. Various options for better fuel exploitation, alternatives for advanced fuelling, and fuel cycle costs are assessed, and out-of-reactor fuel cycle options are compared. (M.D.). 7 refs., 32 refs

Public relations activities of the Service Hall for Kashiwazaki-Kariwa Nuclear Power Station

International Nuclear Information System (INIS)

Kono, T.

1998-01-01

This article includes information of the Service Hall for Kashiwazaki-Kariwa Nuclear Power Station. About 30% of the total electricity production in Japan is due to 16 power stations and 52 reactors. The service hall is a kind of atomic power pavilion for public relations. In Japan, each nuclear power station has such a pavilion, which acts a a center of public relations activities for the atomic power. (S. Grainger)

Reduced order generalized integrators with phase compensation for three-phase active power filter

DEFF Research Database (Denmark)

Xie, Chuan; Li, Kai; Zhao, Xin

2017-01-01

-order generalized integrators (SOGIs) are utilized to achieve those objectives. However, it will increase the computational burden due to calculation of the multiple paralleled SOGIs. To overcome this issue, phase compensated reduced order generalized integrator (ROGI) is proposed in this paper. Compared...... paralleled ROGIs in positive and negative resonant frequencies. Moreover, the controller parameters are designed and optimized by means of Nyquist diagrams and sensitivity functions in z-domain for directly digital implementation. Finally, the laboratory tests of APF are performed to validate the feasibility...

A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

Science.gov (United States)

Taheri, Asghar; Zhalebaghi, Mohammad Hadi

2017-11-01

This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

PPARγ agonist pioglitazone reduces matrix metalloproteinase-9 activity and neuronal damage after focal cerebral ischemia

International Nuclear Information System (INIS)

Lee, Seong-Ryong; Kim, Hahn-Young; Hong, Jung-Suk; Baek, Won-Ki; Park, Jong-Wook

2009-01-01

Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has shown protective effects against ischemic insult in various tissues. Pioglitazone is also reported to reduce matrix metalloproteinase (MMP) activity. MMPs can remodel extracellular matrix components in many pathological conditions. The current study was designed to investigate whether the neuroprotection of pioglitazone is related to its MMP inhibition in focal cerebral ischemia. Mice were subjected to 90 min focal ischemia and reperfusion. In gel zymography, pioglitazone reduced the upregulation of active form of MMP-9 after ischemia. In in situ zymograms, pioglitazone also reduced the gelatinase activity induced by ischemia. After co-incubation with pioglitazone, in situ gelatinase activity was directly reduced. Pioglitazone reduced the infarct volume significantly compared with controls. These results demonstrate that pioglitazone may reduce MMP-9 activity and neuronal damage following focal ischemia. The reduction of MMP-9 activity may have a possible therapeutic effect for the management of brain injury after focal ischemia.

Implementing the strategy of multileveled PI activities to promote rapid nuclear power development

International Nuclear Information System (INIS)

Chen Gang

2005-01-01

The first two decades of the 21st century is the golden time for nuclear power development in China. According to the nuclear power development program laid down by the State Development and Reform Commission, nearly 30 units of 1000MW will be built in the next 15 years, so as to meet fastgrowing energy demand, to optimize energy mix and to alleviate environmental pollution. Under such a new situation, based on the public information practice and experience during the construction and operation of Qinshan Nuclear Power Complex where the first commercial NPP originated in the Mainland of China, this paper emphasizes on the necessity of establishment of an active and open strategy of multileveled nuclear energy public information activities and implementation of the strategy with adoption of various forms of nuclear energy popularization means, including seminars, contests, exhibitions, site tour to nuclear power plants, reports by mass media, hosting questions-answering dialogue by experts via Internet, TV and radio programs, newspapers and journals , etc.. Thus through the nuclear energy public information activity the recognition and confidence of the public, especially the local community and the public in vicinity of new nuclear power sites on the nuclear energy can be enhanced, and the nuclear power program can gain their support. Furthermore, the fine social environment for nuclear power development can be fostered. (authors)

Distributed routing algorithms to manage power flow in agent-based active distribution network

NARCIS (Netherlands)

Nguyen, H.P.; Kling, W.L.; Georgiadis, G.; Papatriantafilou, M.; Anh-Tuan, L.; Bertling, L.

2010-01-01

The current transition from passive to active electric distribution networks comes with problems and challenges on bi-directional power flow in the network and the uncertainty in the forecast of power generation from grid-connected renewable and distributed energy sources. The power flow management

Theta power is reduced in healthy cognitive aging.

Science.gov (United States)

Cummins, Tarrant D R; Finnigan, Simon

2007-10-01

The effects of healthy cognitive aging on electroencephalographic (EEG) theta (4.9-6.8 Hz) power were examined during performance of a modified Sternberg, S., 1966. High-speed scanning in human memory. Science 153, 652-654.) word recognition task. In a sample of fourteen young (mean age 21.9 years, range=18-27) and fourteen older (mean age 68.4 years, range=60-80) participants, theta power was found to be significantly lower in older adults during both the retention and recognition intervals. This theta power difference was greatest at the fronto-central midline electrode and occurred in parallel with a small, non-significant decrease in recognition accuracy in the older sample. A significant decrease in older adults' mean theta power was also observed in resting EEG, however, it was of substantially smaller magnitude than the task-related theta difference. It is proposed that a neurophysiological measure(s), such as task-specific frontal midline theta (fmtheta) power, may be a more sensitive marker of cognitive aging than task performance measures. Furthermore, as recent research indicates that fmtheta is generated primarily in the anterior cingulate cortex, the current findings support evidence that the function of brain networks incorporating this structure may be affected in cognitive aging.

Task failure during exercise to exhaustion in normoxia and hypoxia is due to reduced muscle activation caused by central mechanisms while muscle metaboreflex does not limit performance

Directory of Open Access Journals (Sweden)

Rafael eTorres-Peralta

2016-01-01

Full Text Available To determine whether task failure during incremental exercise to exhaustion (IE is principally due to reduced neural drive and increased metaboreflex activation eleven men (22±2 years performed a 10s control isokinetic sprint (IS; 80 rpm after a short warm-up. This was immediately followed by an IE in normoxia (Nx, PIO2:143 mmHg and hypoxia (Hyp, PIO2:73 mmHg in random order, separated by a 120 min resting period. At exhaustion, the circulation of both legs was occluded instantaneously (300 mmHg during 10 or 60s to impede recovery and increase metaboreflex activation. This was immediately followed by an IS with open circulation. Electromyographic recordings were obtained from the vastus medialis and lateralis. Muscle biopsies and blood gases were obtained in separate experiments. During the last 10s of the IE, pulmonary ventilation, VO2, power output and muscle activation were lower in hypoxia than in normoxia, while pedaling rate was similar. Compared to the control sprint, performance (IS-Wpeak was reduced to a greater extent after the IE-Nx (11% lower P<0.05 than IE-Hyp. The root mean square (EMGRMS was reduced by 38 and 27% during IS performed after IE-Nx and IE-Hyp, respectively (Nx vs. Hyp: P<0.05. Post-ischemia IS-EMGRMS values were higher than during the last 10s of IE. Sprint exercise mean (IS-MPF and median (IS-MdPF power frequencies, and burst duration, were more reduced after IE-Nx than IE-Hyp (P<0.05. Despite increased muscle lactate accumulation, acidification, and metaboreflex activation from 10 to 60s of ischemia, IS-Wmean (+23% and burst duration (+10% increased, while IS-EMGRMS decreased (-24%, P<0.05, with IS-MPF and IS-MdPF remaining unchanged. In conclusion, close to task failure, muscle activation is lower in hypoxia than in normoxia. Task failure is predominantly caused by central mechanisms, which recover to great extent within one minute even when the legs remain ischemic. There is dissociation between the recovery of

The Influence Of Modified Water Chemistries On Metal Oxide Films, Activity Build-Up And Stress Corrosion Cracking Of Structural Materials In Nuclear Power Plants

International Nuclear Information System (INIS)

Maekelae, K.; Laitinen, T.; Bojinov, M.

1998-07-01

The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of activated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for 60 Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (author)

Radioecological studies of activation products released from a nuclear power plant into the marine environment

Energy Technology Data Exchange (ETDEWEB)

Nilsson, M.; Mattsson, S.; Holm, E.

1984-01-01

The Barseback nuclear power plant, located on the Oresund sound between Denmark and Sweden, consists of two boiling water reactors. The release of radionuclides, mainly activation products, is quite low during normal operation. During the summer, when annual overhaul and partial refuelling take place, the discharge is much higher. Samples of seaweeds and crustaceans collected along the coast were analyzed for radionuclides. Seaweeds (Fucus vesiculosus, F. Serratus, Ascophyllum nodosum and Cladophora glomerata) and crustaceans (Idothea and Gammarus) proved to be excellent bioindicators for radioactive corrosion products released from the nuclear power plant into the marine environment. These bioindicators have been used to map the spatial and temporal distribution of the released radioactivity. The activity has been followed up to 150 km from the power plant, and the decrease in activity concentration in the bioindicators with distance can be expressed by a power function. The variation with time of activity concentration reflects the amount of activity discharged from the power plant, with good resolution in time. The bioindicators exhibit different uptake patterns of the radionuclides detected. The crustacean Idothea showed variations in the Co/sup 60/ activity concentration between winter and summer. 9 references, 12 figures, 2 tables.

Reduced In-Plane, Low Frequency Helicopter Noise of an Active Flap Rotor

Science.gov (United States)

Sim, Ben W.; Janakiram, Ram D.; Barbely, Natasha L.; Solis, Eduardo

2009-01-01

Results from a recent joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low frequency noise of the full-scale Boeing-SMART rotor using active flaps. Test data reported in this paper illustrated that acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 decibels at a moderate airspeed, level flight condition corresponding to advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, in a manner, which generated counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency and phase. The associated noise reductions resulted in reduced aural detection distance by up to 18%, but incurred significant vibratory load penalties due to increased hub shear forces. Small reductions in rotor lift-to-drag ratios, of no more than 3%, were also measured

Accounting for response misclassification and covariate measurement error improves power and reduces bias in epidemiologic studies.

Science.gov (United States)

Cheng, Dunlei; Branscum, Adam J; Stamey, James D

2010-07-01

To quantify the impact of ignoring misclassification of a response variable and measurement error in a covariate on statistical power, and to develop software for sample size and power analysis that accounts for these flaws in epidemiologic data. A Monte Carlo simulation-based procedure is developed to illustrate the differences in design requirements and inferences between analytic methods that properly account for misclassification and measurement error to those that do not in regression models for cross-sectional and cohort data. We found that failure to account for these flaws in epidemiologic data can lead to a substantial reduction in statistical power, over 25% in some cases. The proposed method substantially reduced bias by up to a ten-fold margin compared to naive estimates obtained by ignoring misclassification and mismeasurement. We recommend as routine practice that researchers account for errors in measurement of both response and covariate data when determining sample size, performing power calculations, or analyzing data from epidemiological studies. 2010 Elsevier Inc. All rights reserved.

Application of Discontinuous PWM Modulation in Active Power Filters

DEFF Research Database (Denmark)

Blaabjerg, Frede; Asiminoaei, Lucian; Rodriguez, Pedro

2008-01-01

Classical discontinuous pulsewidth modulations (DPWMs) may not be efficiently applied in active power filters (APFs), because it is hard to predict the peak values of the inverter current, and consequently it is difficult to calculate the position of the clamped interval, that minimizes...

Design and analysis of active power control strategies for distributed generation inverters under unbalanced grid faults

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

2010-01-01

Distributed power generation systems are expected to deliver active power into the grid and support it without interruption during unbalanced grid faults. Aiming to provide grid-interfacing inverters the flexibility to adapt to the coming change of grid requirements, an optimised active power

DELIMITATION OF THE DISCRETIONARY POWER FROM THE POWER EXCESS IN THE ACTIVITY OF THE STATE’S AUTHORITIES

Directory of Open Access Journals (Sweden)

MARIUS ANDREESCU

2012-05-01

Full Text Available A problem of essence of the lawful state is to delimitate the discretionary power and respectively, the abuse ofright in the state’s institutions activities. The legal behavior of the state institutions is being materialized by their right of appreciation, and the power excess yields in the violation of a subjective right or a legitimate interest of the citizen. The application and observance of the lawfulness principle in the activity of the state authorities is a complex problem because the exercise of the state’s functions assumes the discretionary power with which the state’s organs are invested with, or otherwise said the ‘right of appreciation” of the state’s authorities regarding the moment of adopting and the contents of the disposed measures. The discretionary power cannot be opposed to the lawfulness principle, as a dimension of the lawful state. In this study we propose ourselves to analyze the discretionary power concepts and respectively, the excess of power, having as landmark the legislation, jurisprudence and the doctrine in the matter. At the same time, we wish to identify the most important criterions that will allow the practitioner, no matter whether he / she is an administrator, a public clerk or a judge, to delimit the legal behavior of the state’s institutions from the power excess. In this regard, we appreciate that the principle of proportionality represents such a criterion. We consider that the law courts, by applying the principle of Constitution’s supremacy, can censor some juridical acts contrary to the constitutional norms, if the Lawmaker does not foresee the competence of the Constitutional Court in this matter. In our opinion, all law courts, within the limits of the competence granted by law, can control and censor the juridical acts of some public authorities issued by power excess. In order to demonstrate these assertions some theoretical and juridical practice arguments are being brought.

An energy harvesting system for passively generating power from human activities

International Nuclear Information System (INIS)

Rao, Yuan; Cheng, Shuo; Arnold, David P

2013-01-01

This paper presents a complete, self-contained energy harvesting system composed of a magnetic energy harvester, an input-powered interface circuit and a rechargeable battery. The system converts motion from daily human activities such as walking, jogging, and cycling into usable electrical energy. By using an input-powered interface circuit, the system requires no external power supplies and features zero standby power when the input motion is too small for successful energy reclamation. When attached to a person's ankle during walking, the 100 cm 3 system prototype is shown to charge a 3.7 V, 65 mAh lithium-ion polymer battery at an average power of 300 µW. The design and testing of the system under other operating conditions are presented herein. (paper)

The significance of reduced respiratory chain enzyme activities: clinical, biochemical and radiological associations.

Science.gov (United States)

Mordekar, S R; Guthrie, P; Bonham, J R; Olpin, S E; Hargreaves, I; Baxter, P S

2006-03-01

Mitochondrial diseases are an important group of neurometabolic disorders in children with varied clinical presentations and diagnosis that can be difficult to confirm. To report the significance of reduced respiratory chain enzyme (RCE) activity in muscle biopsy samples from children. Retrospective odds ratio was used to compare clinical and biochemical features, DNA studies, neuroimaging, and muscle biopsies in 18 children with and 48 without reduced RCE activity. Children with reduced RCE activity were significantly more likely to have consanguineous parents, to present with acute encephalopathy and lactic acidaemia and/or within the first year of life; to have an axonal neuropathy, CSF lactate >4 mmol/l; and/or to have signal change in the basal ganglia. There were positive associations with a maternal family history of possible mitochondrial cytopathy; a presentation with failure to thrive and lactic acidaemia, ragged red fibres, reduced fibroblast fatty acid oxidation and with an abnormal allopurinol loading test. There was no association with ophthalmic abnormalities, deafness, epilepsy or myopathy. The association of these clinical, biochemical and radiological features with reduced RCE activity suggests a possible causative link.

Energy activity guide : simple steps to reduce your household energy use

Energy Technology Data Exchange (ETDEWEB)

Byckalo-Khan, F; Wallace, C L [ed.

2003-07-01

This guide presents 13 practical activities that can help households reduce energy consumption in order to create a more sustainable lifestyle and to help meet Canada's Kyoto commitment to reduce greenhouse gas emissions. Most energy sources create pollution that harms both human health and the Earth. The burning of fossil fuels creates greenhouse gas emissions that contribute to climate change, smog, pollution and adverse health effects. This guide offers suggestions on how households can reduce the impact on the environment while saving money. Some of the initiatives include lowering the thermostat, replacing incandescent light bulbs with compact fluorescent light bulbs, turning off appliances when not in use, weatherising building envelopes, using a clothes line to dry clothes instead of a dryer, laundering clothes with cold water, and proper maintenance of heating equipment. An energy use chart is included with this guide to help track activities and to estimate how much time and money is required by each activity. refs., figs.

Energy activity guide : simple steps to reduce your household energy use

Energy Technology Data Exchange (ETDEWEB)

Byckalo-Khan, F.; Wallace, C.L. (ed.)

2003-07-01

This guide presents 13 practical activities that can help households reduce energy consumption in order to create a more sustainable lifestyle and to help meet Canada's Kyoto commitment to reduce greenhouse gas emissions. Most energy sources create pollution that harms both human health and the Earth. The burning of fossil fuels creates greenhouse gas emissions that contribute to climate change, smog, pollution and adverse health effects. This guide offers suggestions on how households can reduce the impact on the environment while saving money. Some of the initiatives include lowering the thermostat, replacing incandescent light bulbs with compact fluorescent light bulbs, turning off appliances when not in use, weatherising building envelopes, using a clothes line to dry clothes instead of a dryer, laundering clothes with cold water, and proper maintenance of heating equipment. An energy use chart is included with this guide to help track activities and to estimate how much time and money is required by each activity. refs., figs.

Nuclear power plant control and instrumentation activities in Finland

International Nuclear Information System (INIS)

Haapanen, P.; Wahlstroem, B.

1992-01-01

Finland has remarkable achievements in nuclear power. The existing four plants have some of the best operating records in the world - high capacity factors, low occupational doses and short refuelling outages. Public opinion was strongly turned against nuclear power after Chernobyl accident, and the previous government decided not to allow for the construction of a fifth nuclear unit during its period of reign. The opposition has however slowly been diminishing. According to the latest polls the opinion is almost balanced. Finnish power companies are going to file an application for a decision-in-principle to build a new plant to the new government appointed in April 1991. A readiness to start new construction project immediately after a positive political decision is made has been maintained during the intermediate period. Continuous research, development, modification and upgrading work provide important components of the good operational history of the Finnish nuclear power plants. Efforts have also been devoted to identifying possible new problems arising from the use of distributed digital C and I technology. The following a short description is summarizing recent activities related to the C and I-systems of the nuclear power plants. (author). 3 tab

Compensating active power imbalances in power system with large-scale wind power penetration

DEFF Research Database (Denmark)

Basit, Abdul; Hansen, Anca Daniela; Altin, Müfit

2016-01-01

Large-scale wind power penetration can affectthe supply continuity in the power system. This is a matterof high priority to investigate, as more regulating reservesand specified control strategies for generation control arerequired in the future power system with even more highwind power penetrat...

Using active power filter to compensate the current component of asymmetrical non-linear load in the four wire network

Directory of Open Access Journals (Sweden)

Руслан Володимирович Власенко

2016-07-01

Full Text Available Electricity quality improving is extremely relevant nowadays. With such industrial loads as induction motors, induction furnaces, welding machines, controlled or uncontrolled rectifiers, frequency converters and others reactive power, harmonics and unbalance are generated in power grid. Reactive power, higher harmonic currents and asymmetry loads influence the functioning of electric devices and electrical mains. An effective technical solution is the use of new compensating devices, that is active power filters. The emergence of consumers with a unit capacity of four wire networks requires a new approach to building system control active power filter. When designing the active power filter control system the current flowing in the neutral wire must be taken into account. To assess the power balance in the four wire active power filter, scientists have proposed to apply pqr theory of power based on the Clarke transformation. There are different topologies of three-phase four wire active power filters. A visual simulation of Matlab / Simulink model with an active power filter based on pqr theory of power has been created. A method of pulse width modulation with four control channels was used as pulses forming systems with transistor keys. Operating conditions of three-phase four wire active power filter with asymmetry, non-sinosoidal voltage source and asymmetric load have been studied. The correction taking into account the means improving the active power filter has been offered as pqr theory of power does not take into account non-sinosoidal voltage

Evaluation of the activity of synovitis in patients with rheumatoid arthritis: Value of power Doppler ultrasonography

International Nuclear Information System (INIS)

Ahn, Joong Mo; Lim, Hyo Keun; Kim, Seung Hoon; Kim, Sung Hyun; Koh, Eun Mi; Kim, Jin Seok; Cha, Hoon Suk

2001-01-01

To correlate the grades on power Doppler ultrasonography with clinical disease activity indices and acute phase reactant values for assessing the activity of synovitis in patients with rheumatoid arthritis. Twenty patients with rheumatoid arthritis diagnosed on the basis of American College of power Doppler ultrasonography. Two experienced radiologists evaluated, in consensus, the power Doppler signals as follows: grade I=no flow or minimal flow, grade 2=mild flow, grade 3=moderate flow and grade 4= marked flow. The clinical disease activity indices consisted of the counts of tender joints and swollen joints, patient's assessment of pain, patient's global assessment of disease activity, physician's globe assessment of disease activity and patient's assessment of physical function. Acute-phase reactants included CRP and ESR. The grades on power Doppler ultrasonography were correlated with clinical disease activity indices as well as acute-phases reactant values by a use of Spearman rank correlation coefficient. The grades on power Doppler ultrasonography showed a statistically significant correlation with tender joint count (rs=.835; p<.05), swollen joint count (rs=.833; p<.05), physician's global assessment of disease activity (rs=.857; p<.05), CRP (rs=.838; P<.05) and ESR (rs=.838; p<.05). The power Doppler ultrasonography is an useful diagnostic modality for assessing the activity of synovitis in patients with rheumatoid arthritis.

Personnel radiation safety in nuclear power plants

International Nuclear Information System (INIS)

Elkert, J.

1979-05-01

The principal contributions to the radiation doses of the Swedish power reactor personnel are identified. The possi bilities to reduce these doses are examined. The radiation doses are analyzed according to different personnel categories, specific maintenance operations or inspections and to different radiation activities. Suggestions are given for reducing the radiation doses. (L.E.)

Adaptive co-channel interference cancelation for power-limited applications

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2010-09-01

This paper proposes an adaptive co-channel interference -steering algorithm for highly correlated receive antenna channels with an aim of reducing the power consumption at the receiver. With this algorithm, the receiver activates as many antennas as necessary to maintain the residual total interference instantaneous power within a tolerable range, which can be set to guarantee a target performance level. The mode of operation does not require perfect knowledge of the statistical ordering of interfering signals instantaneous powers, which further reduces the complexity of implementation. It is shown that the arbitrary interference cancelation technique and no cancelation scenario can be studied as limiting cases of the proposed scheme. Analytical expressions for the statistics of the residual total interference instantaneous power are derived, which are then used to obtain results for the average number of active antennas and system outage performance. Numerical studies supported by simulations are presented to clarify the usefulness of the proposed scheme. ©2010 IEEE.

A study of overseas research activities for thorium reactors and the need for the introduction of the domestic nuclear power

International Nuclear Information System (INIS)

Park, Dongwon; Park, Keunteag

2013-01-01

Many countries have been proceeding research actively in this area as highlighted these advantages but de facto, there are not official research activities in Korea. This paper is to analyze the current status of research in some countries and describe the possibilities introduce with necessity in Korea. Radiation and the radioactive waste, decay heat, loss of coolant accident that related with safety issue are always emerging as a problem of social acceptance of nuclear power plant. Proportion of U- 235 , uranium fuel is only 3-5% and the rest of U- 238 is discarded as all nuclear waste in accordance with 'Open Cycle.' Even if put to practical use thorium reactor, nuclear waste generated but can significantly reduce the toxicity nuclides of TRU and not only the decay heat that physical cause of Fukushima nuclear power plant accident does not occur but also do not need to worry about the LOCA. Our nuclear power plant have been operated very safety compared to Japan. Relative to unexpected operation stop status in terms of base 5 years previous of Fukushima nuclear accident are 0.5 based on average value in our nuclear power plants on the other hand 0.4 in total 17 units of nuclear power plant subsidiary Tokyo Electric Power co., Japan. It is similar to ours, and is similar to Kansai Electric Power Co. However, total reported incidents of non-severe accidents are much higher than ours. But that cannot be interpreted as the safety of our operating skills of nuclear power plant are excellent compared to other countries. For many people's anxiety about nuclear power plants operating after the Fukushima accident, nuclear operators emphasized the safety of our nuclear power plant with referring to the difference between PWR and BWR. Our nuclear power plant were complementary in many facilities depend on problems revealed at the Fukushima nuclear power plant. But it seems to be need for long-term research and development of next-generation nuclear power plant that safety

Active Recovery between Interval Bouts Reduces Blood Lactate While Improving Subsequent Exercise Performance in Trained Men

Directory of Open Access Journals (Sweden)

Harutiun M. Nalbandian

2017-06-01

Full Text Available This study aimed to examine the blood lactate and blood pH kinetics during high-intensity interval training. Seventeen well-trained athletes exercised on two different occasions. Exercises consisted of three 30 s bouts at a constant intensity (90% of peak power with 4 min recovery between bouts followed by a Wingate test (WT. The recoveries were either active recovery (at 60% of the lactate threshold intensity or passive recovery (resting at sitting position. During the exercise, blood samples were taken to determine blood gasses, blood lactate, and blood pH, and peak and average power were calculated for the WT. When performing the active recovery trials, blood pH was significantly higher (p < 0.01 and blood lactate was significantly lower (p < 0.01 compared with the passive recovery trials. WT performance was significantly higher in the active recovery trials: peak power was 671 ± 88 and 715 ± 108 watts, and average power was 510 ± 70 and 548 ± 73 watts (passive and active respectively; p < 0.01. However, no statistically significant correlations were found between the increased pH and the increased performance in the active recovery trials. These results suggest that active recovery performed during high-intensity interval exercise favors the performance in a following WT. Moreover, the blood pH variations associated with active recovery did not explain the enhanced performance.

Development for low-activation concrete design reducing radioactive waste

International Nuclear Information System (INIS)

Kimura, Ken-ichi; Kinno, Masaharu; Hasegawa, Akira

2008-01-01

Full text: Concrete is very valuable and inexpensive material, however it can be changed to be expensive and hard to deal with in use of a nuclear plant after long operation. One of the counter plans for the above is to use low-activation concrete instead of the ordinary concrete, that will reduce radioactive waste and could be even below clearance level in decommissioning and that is very useful in term of life cycle cost. Radioactive analysis showed that Co and Eu were the major target elements which decide the radioactivity level of reinforced concrete in decommissioning stage, and a several material were selected as a low-activation raw material from wide survey of raw materials for concrete (typically aggregates and cements). With the canditate of raw materials, several low-activation concrete were proposed for various portion of light water reactor plant, which reduction ratio were 1/10 to 1/30 which were mainly consist of limestone and low heat cement or white cement, and 1/100 to 1/300 which were mainly consist of alumina aggregate or quartz and high almina cement, comparing to the ordinary concrete in ΣDi/Ci unit, where 'Di' indicates concentration of each residual radioisotope, Ci defined by IAEA as a clearance level, and suffition of 'i' indicates each radioisotope. National funded project for development of low-activation design method for reduction of radioactive waste below clearance level were started from 2005 with aiming (1) development of a database on the content of target elements, which transform radioactive nuclides, in raw materials of reinforced concrete, (2) development of calculation tools for estimation of residual radioactivity of plant components, and (3) development of low-activation materials for concrete such as cements and reinforcing steel bars for structural components. For the optimized design for applying low-activation concrete to the reactor portion, effective evaluation of neutron spectrum in the certain portion including

Antioxidative activities of hydrolysates from edible birds nest using enzymatic hydrolysis

Science.gov (United States)

Muhammad, Nurul Nadia; Babji, Abdul Salam; Ayub, Mohd Khan

2015-09-01

Edible bird's nest protein hydrolysates (EBN) were prepared via enzymatic hydrolysis to investigate its antioxidant activity. Two types of enzyme (alcalase and papain) were used in this study and EBN had been hydrolysed with different hydrolysis time (30, 60, 90 and 120 min). Antioxidant activities in EBN protein hydrolysate were measured using DPPH, ABTS+ and Reducing Power Assay. From this study, increased hydrolysis time from 30 min to 120 min contributed to higher DH, as shown by alcalase (40.59%) and papain (24.94%). For antioxidant assay, EBN hydrolysed with papain showed higher scavenging activity and reducing power ability compared to alcalase. The highest antioxidant activity for papain was at 120 min hydrolysis time with ABTS (54.245%), DPPH (49.78%) and Reducing Power (0.0680). Meanwhile for alcalase, the highest antioxidant activity was at 30 min hydrolysis time. Even though scavenging activity for EBN protein hydrolysates were high, the reducing power ability was quite low as compared to BHT and ascorbic Acid. This study showed that EBN protein hydrolysate with alcalase and papain treatments potentially exhibit high antioxidant activity which have not been reported before.

Employment within the power supply industry and the power supply related activities; Sysselsatte i kraftnaeringen og kraftrelatert virksomhet 2011

Energy Technology Data Exchange (ETDEWEB)

Thoen, Haavard

2012-07-01

The report's main objective is to investigate employment within the power supply industry and the power supply related activities. The report will describe the composition of employees in regard to sex, age and education. The power supply industry is defined in Statistics Norway's Standard Industrial Classification, as 'Production and distribution of electricity'. The group of companies related to power supply related activities employ similar persons in regard to education and occupation, typical to companies in the power supply industry. These two groups make up the power supply sector in this report. In 2011 there were 18 450 employees in the power supply sector. This constitutes an increase of nearly 13.5 per cent since 2004 and 1.1 per cent since 2010. The sex distribution of about 80 per cent men and 20 per cent women has been fairly stable since 2004. The power supply sector has a low share of women among its employees compared to the private sector in general. In 2011 the level of education in the power supply sector was higher than for the private sector in general. Since 2004, the share of persons with higher education has increased from 27 to 33 per cent. Employees in the power supply sector are on average older than employees in the private sector. The employees have matured since 2004, but in the last few years, there have also been signs of fresh recruitment. The power supply industry had a net influx of 380 new employees, in the period between 2009 and 2011. There were 1678 new employees and 1298 employees lost in the sector due to attrition. If we look at the supply of new employees who were also employed in 2010, 14.2 percent of female employees worked in temporary staff recruitment agencies. Temporary work seems to be an important entry gate to the power supply industry for women. Among men, the building- and construction sector was the most common background for new employees in the power supply industry. Among people who quit

Intelligent solar-powered automobile-ventilation system

International Nuclear Information System (INIS)

Huang, K. David; Tzeng, S.-C.; Ma Weiping; Wu Mingfung

2005-01-01

This study adopts airflow management technology to improve the local temperature distributions in an automobile to counteract the greenhouse effect. The automobile's temperature can be reduced to almost the outside temperature before the driver or passenger gets into the vehicle. When the engine is idling, the greenhouse-control system can be activated to remove the hot air from the car. An appropriate negative pressure is maintained to prevent stuffiness and save energy. The greenhouse-control system requires electrical power when the engine is idle, and a battery cannot supply sufficient power. An auxiliary solar-power supply can save energy and reduce the greenhouse effect of sunlight, while creating a comfortable traveling environment. It ensures that the engine is not overburdened and increases its service life, conserving energy, protecting the environment and improving comfort

Reducing the Risk of Damage to Power Transformers of 110 kV and Above Accompanying Internal Short Circuits

Energy Technology Data Exchange (ETDEWEB)

L’vova, M. M. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); L’vov, S. Yu. [Presselektro LLC (Russian Federation); Komarov, V. B. [IPCE RAS (Russian Federation); Lyut’ko, E. O. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); Vdoviko, V. P. [EMA Ltd. (Russian Federation); Demchenko, V. V. [JSC “Boguchanskaya HPP” (Russian Federation); Belyaev, S. G. [PKF Konif Ltd. (Russian Federation); Savel’ev, V. A. [Ivanovo State Power University (Russian Federation); L’vov, M. Yu., E-mail: timashova@nte-power.ru; L’vov, Yu. N. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation)

2015-03-15

Methods of increasing the operating reliability of power transformers, autotransformers and shunting reactors in order to reduce the risk of damage, which accompany internal short circuits and equipment fires and explosions, are considered.

Characterization of RNS multiply-add units for power efficient DSP

DEFF Research Database (Denmark)

Cardarilli, Gian Carlo; Nannarelli, Alberto; Petricca, Massimo

2015-01-01

) for a fused multiply-add unit by taking into account four metrics: area, delay, power consumption, and switching activity. The results of the DSE are verified against the TCS and RNS implementation of parallel FIR filters of different characteristics. In both the DSE and the filter implementation, we consider......In the past decades, the Residue Number System (RNS) has been adopted in DSP as an alternative to the traditional two's complement number system (TCS) because of the savings in area, higher speed and reduced power dissipation. In this work, we perform a comprehensive Design Space Exploration (DSE...... two design corners: maximum speed and minimum area. The experimental results demonstrate that for high data rates and high order filters, the RNS implementation is more power efficient than the TCS because of the reduced switching activity and the larger amount of low-power cells placed in the unit....

A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

Directory of Open Access Journals (Sweden)

T. Demirdelen

2016-10-01

Full Text Available In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

Reduction technique of drop voltage and power losses to improve power quality using ETAP Power Station simulation model

Science.gov (United States)

Satrio, Reza Indra; Subiyanto

2018-03-01

The effect of electric loads growth emerged direct impact in power systems distribution. Drop voltage and power losses one of the important things in power systems distribution. This paper presents modelling approach used to restructrure electrical network configuration, reduce drop voltage, reduce power losses and add new distribution transformer to enhance reliability of power systems distribution. Restructrure electrical network was aimed to analyse and investigate electric loads of a distribution transformer. Measurement of real voltage and real current were finished two times for each consumer, that were morning period and night period or when peak load. Design and simulation were conduct by using ETAP Power Station Software. Based on result of simulation and real measurement precentage of drop voltage and total power losses were mismatch with SPLN (Standard PLN) 72:1987. After added a new distribution transformer and restructrured electricity network configuration, the result of simulation could reduce drop voltage from 1.3 % - 31.3 % to 8.1 % - 9.6 % and power losses from 646.7 watt to 233.29 watt. Result showed, restructrure electricity network configuration and added new distribution transformer can be applied as an effective method to reduce drop voltage and reduce power losses.

Comparative study of the base activity levels of the Spanish continental nuclear power stations

International Nuclear Information System (INIS)

Gregorides de los Santos y Perez-Minguez, A.M.

1980-01-01

In this work the pre-operational activity levels of the sites of some Spanish nuclear power stations are discussed. These power stations are located near the Tagus and Ebro river basins. A report of the communities investigated is made. The total alpha and beta activity as well as the long half life activity has been researched there. The importance of this question is obvious for it gives a regional average of the base activity in the basins of these two big Spanish rivers [fr

On Electrohydraulic Pressure Control for Power Steering Applications : Active Steering for Road Vehicles

OpenAIRE

Dell'Amico, Alessandro

2016-01-01

This thesis deals with the Electrohydraulic Power Steering system for road vehicles, using electronic pressure control valves. With an ever increasing demand for safer vehicles and fewer traffic accidents, steering-related active safety functions are becoming more common in modern vehicles. Future road vehicles will also evolve towards autonomous vehicles, with several safety, environmental and financial benefits. A key component in realising such solutions is active steering. The power steer...

Evaluation of Reduced Power Spectra from Three-Dimensional k-Space

Science.gov (United States)

Saur, J.; von Papen, M.

2014-12-01

We present a new tool to evaluate one dimensional reduced power spectral densities (PSD) from arbitrary energy distributions in kk-space. This enables us to calculate the power spectra as they are measured in spacecraft frame for any given measurement geometry assuming Taylor's frozen-in approximation. It is possible to seperately calculate the diagonal elements of the spectral tensor and also to insert additional, non-turbulent energy in kk-space (e.g. mirror mode waves). Given a critically balanced turbulent cascade with k∥˜kα⊥k_\\|sim k_perp^alpha, we explore the implications on the spectral form of the PSD and the functional dependence of the spectral index κkappa on the field-to-flow angle θtheta between plasma flow and background magnetic field. We show that critically balanced turbulence develops a θtheta-independent cascade with the spectral slope of the perpendicular cascade κ(θ=90∘)kappa(theta{=}90^circ). This happens at frequencies f>fmaxf>f_mathrm{max}, where fmax(L,α,θ)f_mathrm{max}(L,alpha,theta) is a function of outer scale LL, critical balance exponent αalpha and field-to-flow angle θtheta. We also discuss potential damping terms acting on the kk-space distribution of energy and their effect on the PSD. Further, we show that the functional dependence κ(θ)kappa(theta) as found by textit{Horbury et al.} (2008) and textit{Chen et al.} (2010) can be explained with a damped critically balanced turbulence model.

Optimized PWR power ascension reload testing

International Nuclear Information System (INIS)

Emery, S.P.; Long, S.W.; Nazareth, V.F.; Herschthal, M.A.

1987-01-01

Reduction in critical path testing time following refueling is actively supported by utilities to increase plant capacity factor and to minimize replacement power costs. Combustion Engineering (C-E) has developed a fast power ascension program (FPAP), which reduces this critical path testing by minimizing holds at intermediate power levels and by automating data acquisition and analysis. A very successful demonstration of the FPAP was performed recently during the cycle 3 startup of Southern California Edison's San Onofre Unit 2 reactor, which resulted in a critical path time savings of ∼ 3 days

Junction temperature estimation for an advanced active power cycling test

DEFF Research Database (Denmark)

Choi, Uimin; Blaabjerg, Frede; Jørgensen, S.

2015-01-01

estimation method using on-state VCE for an advanced active power cycling test is proposed. The concept of the advanced power cycling test is explained first. Afterwards the junction temperature estimation method using on-state VCE and current is presented. Further, the method to improve the accuracy...... of the maximum junction temperature estimation is also proposed. Finally, the validity and effectiveness of the proposed method is confirmed by experimental results.......On-state collector-emitter voltage (VCE) is a good indicator to determine the wear-out condition of power device modules. Further, it is a one of the Temperature Sensitive Electrical Parameters (TSEPs) and thus can be used for junction temperature estimation. In this paper, the junction temperature...

Differential responses of nitrate reducer community size, structure, and activity to tillage systems.

Science.gov (United States)

Chèneby, D; Brauman, A; Rabary, B; Philippot, L

2009-05-01

The main objective of this study was to determine how the size, structure, and activity of the nitrate reducer community were affected by adoption of a conservative tillage system as an alternative to conventional tillage. The experimental field, established in Madagascar in 1991, consists of plots subjected to conventional tillage or direct-seeding mulch-based cropping systems (DM), both amended with three different fertilization regimes. Comparisons of size, structure, and activity of the nitrate reducer community in samples collected from the top layer in 2005 and 2006 revealed that all characteristics of this functional community were affected by the tillage system, with increased nitrate reduction activity and numbers of nitrate reducers under DM. Nitrate reduction activity was also stimulated by combined organic and mineral fertilization but not by organic fertilization alone. In contrast, both negative and positive effects of combined organic and mineral fertilization on the size of the nitrate reducer community were observed. The size of the nitrate reducer community was a significant predictor of the nitrate reduction rates except in one treatment, which highlighted the inherent complexities in understanding the relationships the between size, diversity, and structure of functional microbial communities along environmental gradients.

Consequences of reduced production of electricity in nuclear power plants

International Nuclear Information System (INIS)

The Swedish Power Administration has assessed the possibilities of expanding electric power sources other than nuclear power plants for the years 1980 and 1985. Reports on costs in the form of loss of capital and increased operating costs involved in the dismantling of nuclear power plants are made in Supplement 1. The economics division of the Finance Department, starting with a long-range study model of the Swedish economy, has calculated the consequences of a cutback in electric power up to 1980 for Sweden's economy and employment in that year. The consequences of reduction of electricity supplies up to 1985 are summarized in Supplement 2 in this report. It is concluded that in order to be able to manage the problem of supplying electricity by 1985, it will be necessary to increase oil power above what was assumed in the energy policy program. There will have to be new oil-based power as well. According to the Power Administration, oil-power facilities can be expanded to varying degrees, depending upon when the decision is made. The Power Administration's calculations show that 125 TWh is possible in 1985 without nuclear power only if a decision for discontinuation is made in the fall of 1976. This is based on very optimistic assumptions about the time of execution of a program for oil-steam operation, and also on the assumption that extreme measures will be initiated to force expansion of both district-heating distribution and power + heat facilities. Oil consumption for production of electricity in such an electric power system would be about 9 million m 3 , which is about 5 times more than at present and about one-third of the present total consumption of petroleum products in Sweden

Public acceptance (PA) activities of nuclear power in Japan

International Nuclear Information System (INIS)

Yamada, Masafumi; Iguchi, Tatsuro

1993-10-01

At the first part of presentation present status of nuclear power development in Japan is described. Then results of poll on nuclear energy acceptance by population are analyzed. Further, current activities and future efforts directed to broad understanding by people benefits of nuclear energy are described. 6 figs

Thorium fuel for light water reactors - reducing proliferation potential of nuclear power fuel cycle

Energy Technology Data Exchange (ETDEWEB)

Galperin, A; Radkowski, A [Ben-Gurion Univ. of the Negev, Beersheba (Israel)

1996-12-01

The proliferation potential of the light water reactor fuel cycle may be significantly reduced by utilization of thorium as a fertile component of the nuclear fuel. The main challenge of Th utilization is to design a core and a fuel cycle, which would be proliferation-resistant and economically feasible. This challenge is met by the Radkowsky Thorium Reactor (RTR) concept. So far the concept has been applied to a Russian design of a 1,000 MWe pressurized water reactor, known as a WWER-1000, and designated as VVERT. The following are the main results of the preliminary reference design: * The amount of Pu contained in the RTR spent fuel stockpile is reduced by 80% in comparison with a VVER of a current design. * The isotopic composition of the RTR-Pu greatly increases the probability of pre-initiation and yield degradation of a nuclear explosion. An extremely large Pu-238 content causes correspondingly large heat emission, which would complicate the design of an explosive device based on RTR-Pu. The economic incentive to reprocess and reuse the fissile component of the RTR spent fuel is decreased. The once-through cycle is economically optimal for the RTR core and cycle. To summarize all the items above: the replacement of a standard (U-based) fuel for nuclear reactors of current generation by the RTR fuel will provide an inherent barrier for nuclear weapon proliferation. This inherent barrier, in combination with existing safeguard measures and procedures is adequate to unambiguously disassociate civilian nuclear power from military nuclear power. * The RTR concept is applied to existing power plants to assure its economic feasibility. Reductions in waste disposal requirements, as well as in natural U and fabrication expenses, as compared to a standard WWER fuel, provide approximately 20% reduction in fuel cycle (authors).

Reduced salience and default mode network activity in women with anorexia nervosa

Science.gov (United States)

McFadden, Kristina L.; Tregellas, Jason R.; Shott, Megan E.; Frank, Guido K.W.

2014-01-01

Background The neurobiology of anorexia nervosa is poorly understood. Neuronal networks contributing to action selection, self-regulation and interoception could contribute to pathologic eating and body perception in people with anorexia nervosa. We tested the hypothesis that the salience network (SN) and default mode network (DMN) would show decreased intrinsic activity in women with anorexia nervosa and those who had recovered from the disease compared to controls. The basal ganglia (BGN) and sensorimotor networks (SMN) were also investigated. Methods Between January 2008 and January 2012, women with restricting-type anorexia nervosa, women who recovered from the disease and healthy control women completed functional magnetic resonance imaging during a conditioned stimulus task. Network activity was studied using independent component analysis. Results We studied 20 women with anorexia nervosa, 24 recovered women and 24 controls. Salience network activity in the anterior cingulate cortex was reduced in women with anorexia nervosa (p = 0.030; all results false-discovery rate–corrected) and recovered women (p = 0.039) compared to controls. Default mode network activity in the precuneus was reduced in women with anorexia compared to controls (p = 0.023). Sensorimotor network activity in the supplementary motor area (SMA; p = 0.008), and the left (p = 0.028) and right (p = 0.002) postcentral gyrus was reduced in women with anorexia compared to controls; SMN activity in the SMA (p = 0.019) and the right postcentral gyrus (p = 0.008) was reduced in women with anorexia compared to recovered women. There were no group differences in the BGN. Limitations Differences between patient and control populations (e.g., depression, anxiety, medication) are potential confounds, but were included as covariates. Conclusion Reduced SN activity in women with anorexia nervosa and recovered women could be a trait-related biomarker or illness remnant, altering the drive to approach

Wireless power pad with local power activation for portable devices

NARCIS (Netherlands)

Waffenschmidt, E.; Zheglov, V.

2007-01-01

Wireless power transfer by magnetic induction offers a simple to use way to recharge mobile devices like e.g. mobile phone, music players or medical sensors. As shown by a previous report and an existing Power Pad demonstrator, wireless inductive power transfer is possible with a good power

Demonstration of Active Power Controls by Utility-Scale PV Power Plant in an Island Grid: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gevorgian, Vahan; O' Neill, Barbara

2017-02-01

The National Renewable Energy Laboratory (NREL), AES, and the Puerto Rico Electric Power Authority conducted a demonstration project on a utility-scale photovoltaic (PV) plant to test the viability of providing important ancillary services from this facility. As solar generation increases globally, there is a need for innovation and increased operational flexibility. A typical PV power plant consists of multiple power electronic inverters and can contribute to grid stability and reliability through sophisticated 'grid-friendly' controls. In this way, it may mitigate the impact of its variability on the grid and contribute to important system requirements more like traditional generators. In 2015, testing was completed on a 20-MW AES plant in Puerto Rico, and a large amount of test data was produced and analyzed that demonstrates the ability of PV power plants to provide various types of new grid-friendly controls. This data showed how active power controls can leverage PV's value from being simply an intermittent energy resource to providing additional ancillary services for an isolated island grid. Specifically, the tests conducted included PV plant participation in automatic generation control, provision of droop response, and fast frequency response.

Ventricular activity cancellation in electrograms during atrial fibrillation with constraints on residuals' power.

Science.gov (United States)

Corino, Valentina D A; Rivolta, Massimo W; Sassi, Roberto; Lombardi, Federico; Mainardi, Luca T

2013-12-01

During atrial fibrillation (AF), cancellation of ventricular activity from atrial electrograms (AEG) is commonly performed by template matching and subtraction (TMS): a running template, built in correspondence of QRSs, is subtracted from the AEG to uncover atrial activity (AA). However, TMS can produce poor cancellation, leaving high-power residues. In this study, we propose to modulate the templates before subtraction, in order to make the residuals as similar as possible to the nearby atrial activity, avoiding high-power ones. The coefficients used to modulate the template are estimated by maximizing, via Multi-swarm Particle Swarm Optimization, a fitness function. The modulated TMS method (mTMS) was tested on synthetic and real AEGs. Cancellation performances were assessed using: normalized mean squared error (NMSE, computed on simulated data only), reduction of ventricular activity (VDR), and percentage of segments (PP) whose power was outside the standard range of the atrial power. All testings suggested that mTMS is an improvement over TMS alone, being, on simulated data, NMSE and PP significantly decreased while VDR significantly increased. Similar results were obtained on real electrograms (median values of CS1 recordings PP: 2.44 vs. 0.38 p < 0.001; VDR: 6.71 vs. 8.15 p < 0.001). Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Worldwide activities on the reduction of occupational exposure at nuclear power plants

International Nuclear Information System (INIS)

Kahn, T.A.; Baum, J.W.

1988-06-01

This report is based on analysis of an informational data base set up at the Brookhaven National Laboratory ALARA Center. It is part of a project sponsored by the US Nuclear Regulatory Commission to monitor and evaluate research on dose reduction at nuclear power plants in the US and abroad. The main benefits to be expected from reducing occupational exposures are highlighted in the report, the chief causes of elevated doses are identified, and effective approaches to minimize radiation exposures are proposed. A wide range of research activity is covered, including plant chemistry, cobalt reduction techniques, stress corrosion cracking, decontamination, remote tools and devices, and robotics. Advanced reactors, which are designed for low radiation exposures, are examined, and health physics technology programs which have been effective in reducing occupational exposure at various utilities are discussed. The highlights of the programs on dose reduction conducted by a number of countries are described, and comparisons are made of the collective occupational radiation dose equivalents for selected countries. The short and long term trends such studies are pointing to are evaluated. It is concluded that the efforts to improve dose reduction, both in the US and abroad, remain in a healthy state but require continuing encouragement and further development

Ferroelectric switch for a high-power Ka-band active pulse compressor

Energy Technology Data Exchange (ETDEWEB)

Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

2013-12-18

Results are presented for design of a high-power microwave switch for operation at 34.3 GHz, intended for use in an active RF pulse compressor. The active element in the switch is a ring of ferroelectric material, whose dielectric constant can be rapidly changed by application of a high-voltage pulse. As envisioned, two of these switches would be built into a pair of delay lines, as in SLED-II at SLAC, so as to allow 30-MW μs-length Ka-band pulses to be compressed in time by a factor-of-9 and multiplied in amplitude to generate 200 MW peak power pulses. Such high-power pulses could be used for testing and evaluation of high-gradient mm-wave accelerator structures, for example. Evaluation of the switch design was carried out with an X-band (11.43 GHz) prototype, built to incorporate all the features required for the Ka-band version.

Activated charcoal and baking soda to reduce odor associated with extensive blistering disorders.

Science.gov (United States)

Chakravarthi, Arun; Srinivas, C R; Mathew, Anil C

2008-01-01

Skin disease leading to extensive blistering and loss of skin is associated with a characteristic smell. Odor can cause physiologic disturbances such as increase in heart rate and respiratory rate. It can also cause nausea and vomiting and is disturbing to bystanders. To test odor reducing capability of activated charcoal. In this blinded experimental study we used putrefied amniotic membrane to produce odor and studied the effectiveness of activated charcoal and soda-bi-carbonate to reduce odor. Statistical analysis with Kruskal Wall's Chi Square Test and Man Whitney U test showed significant reduction of odor using activated charcoal by itself or along with soda-bi-carbonate. We recommend the usage of activated charcoal with/without soda bicarbonate as an inexpensive practical measure to reduce foul odor associated with extensive skin loss.

Nuclear power plant siting

International Nuclear Information System (INIS)

Sulkiewicz, M.; Navratil, J.

The construction of a nuclear power plant is conditioned on territorial requirements and is accompanied by the disturbance of the environment, land occupation, population migration, the emission of radioactive wastes, thermal pollution, etc. On the other hand, a nuclear power plant makes possible the introduction of district heating and increases the economic and civilization activity of the population. Due to the construction of a nuclear power plant the set limits of negative impacts must not be exceeded. The locality should be selected such as to reduce the unfavourable effects of the plant and to fully use its benefits. The decision on the siting of the nuclear power plant is preceded by the processing of a number of surveys and a wide range of documentation to which the given criteria are strictly applied. (B.H.)

Control of a three-phase four-wire shunt-active power filter based on DC-bus energy regulation

DEFF Research Database (Denmark)

Blaabjerg, Frede; Teodorescu, Remus; Rodriguez, Pedro

2008-01-01

This paper presents a nonconventional three-phase four-wire shunt active power filter (APF) topology controlled by using an energy approach. A general study of power terms involved in the operation of the four-wire APF is conducted in order to evidence the relationship between instantaneous energy...... stored in the DC bus and active power requirements on the APF. Harmonics and imbalances both on the utility voltage and load current have been considered and the power developed by the active power filter has been evaluated. This study allows designing a controller for the APF based on the regulation...

TRANSIENT ANALYSIS OF WIND DIESEL POWER SYSTEM WITH FLYWHEEL ENERGY STORAGE

Directory of Open Access Journals (Sweden)

S. SUJITH

2017-10-01

Full Text Available Wind-Diesel Hybrid power generation is a viable alternative for generating continuous power to isolated power system areas which have inconsistent but potential wind power. The unpredictable nature of variable power from Wind generator to the system is compensated by Diesel generator, which supplies the deficit in generated power from wind to meet the instantaneous system load. However, one of the major challenges for such a system is the higher probability of transients in the form of wind and load fluctuations. This paper analyses the application of Flywheel Energy storage system (FESS to meet the transients during wind-speed and load fluctuations around high wind operation. The power system architecture, the distributed control mechanism governing the flow of power transfer and the modelling of major system components has been discussed and the system performances have been validated using MATLAB /Simulink software. Two cases of transient stages around the high wind system operation are discussed. The simulation results highlight the effective usage of FESS in reducing the peak overshoot of active power transients, smoothes the active power curves and helps in reducing the diesel consumption during the flywheel discharge period, without affecting the continuous power supply for meeting the instantaneous load demand.

Reducing braking distance by control of semi-active suspension

Energy Technology Data Exchange (ETDEWEB)

Niemz, T.

2007-07-01

This thesis presents a control algorithm for semi-active suspensions to reduce the braking distance of passenger cars. Active shock absorbers are controlled and used to influence the vertical dynamics during ABS-controlled full braking. The core of the approach presented in this paper is based on a switching control logic. The control algorithm is implemented in a compact class passenger car. Test drives on a real road, using a braking machine for reproducibility reasons, have been executed. It could be shown that it is possible to reduce the braking distance by affecting on the vertical dynamics of a passenger car in general. This is the first experimental result of this kind published ever. The amount of reduction depends on the height profile of the testing track chosen and on the initial velocity. On a road with an unevenness comparable to the one on a typical German Autobahn an average reduction of 1-2%, compared to the best passive damping, was achieved. (orig.)

Impaired voluntary neuromuscular activation limits muscle power in mobility-limited older adults

Science.gov (United States)

Background. Age-related alterations of neuromuscular activation may contribute to deficits in muscle power and mobility function. This study assesses whether impaired activation of the agonist quadriceps and antagonist hamstrings, including amplitude- and velocity-dependent characteristics of activa...

Removing radio-active wastes from nuclear power stations by the STEAG system

International Nuclear Information System (INIS)

Baatz, H.

1978-01-01

The mobile STEAG System for conditioning radio-active wastes from nuclear power stations represents a particularly safe and economic method of removing them in present day conditions. Cementation by the FAFNIR System is used for the greater part of the waste, the liquid concentrate (evaporator concentrate and filter slurry). For the special case of the medium active resin balls from the primary circuits, embedding in plastic by the FAMA process has proved to be the only available successful process so far. The highly active solid waste from the reactor core is decomposed by the MOSAIK System, is packed in transportable and storable containers and is removed from the fuel element storage pond. The systems are so safe that faults or interruptions of power station operation due to faults in removing radio-active wastes can be excluded. (orig.) [de

The interdependence of Ca2+ activation, sarcomere length, and power output in the heart.

Science.gov (United States)

McDonald, Kerry S

2011-07-01

Myocardium generates power to perform external work on the circulation; yet, many questions regarding intermolecular mechanisms regulating power output remain unresolved. Power output equals force × shortening velocity, and some interesting new observations regarding control of these two factors have arisen. While it is well established that sarcomere length tightly controls myocyte force, sarcomere length-tension relationships also appear to be markedly modulated by PKA-mediated phosphorylation of myofibrillar proteins. Concerning loaded shortening, historical models predict independent cross-bridge mechanics; however, it seems that the mechanical state of one population of cross-bridges affects the activity of other cross-bridges by, for example, recruitment of cross-bridges from the non-cycling pool to the cycling force-generating pool during submaximal Ca(2+) activation. This is supported by the findings that Ca(2+) activation levels, myofilament phosphorylation, and sarcomere length are all modulators of loaded shortening and power output independent of their effects on force. This fine tuning of power output probably helps optimize myocardial energetics and to match ventricular supply with peripheral demand; yet, the discernment of the chemo-mechanical signals that modulate loaded shortening needs further clarification since power output may be a key convergent point and feedback regulator of cytoskeleton and cellular signals that control myocyte growth and survival.

Data analysis on work activities in dismantling of Japan Power Demonstration Reactor (JPDR). Contract research

International Nuclear Information System (INIS)

Shiraishi, Kunio; Sukegawa, Takenori; Yanagihara, Satoshi

1998-03-01

The safe dismantling of a retired nuclear power plant was demonstrated by completion of dismantling activities for the Japan Power Demonstration Reactor (JPDR), March, 1996, which had been conducted since 1986. This project was a flag ship project for dismantling of nuclear power plants in Japan, aiming at demonstrating an applicability of developed dismantling techniques in actual dismantling work, developing database on work activities as well as dismantling of components and structures. Various data on dismantling activities were therefore systematically collected and these were accumulated on computer files to build the decommissioning database; dismantling activities were characterized by analyzing the data. The data analysis resulted in producing general forms such as unit activity factors, for example, manpower need per unit weight of component to be dismantled, and simple arithmetic forms for forecasting of project management data to be applied to planning another dismantling project through the evaluation for general use of the analyzed data. The results of data analysis could be usefully applied to planning of future decommissioning of commercial nuclear power plants in Japan. This report describes the data collection and analysis on the JPDR dismantling activities. (author)

Solar Ultraviolet-B Radiation Increases Phenolic Content and Ferric Reducing Antioxidant Power in Avena sativa

Directory of Open Access Journals (Sweden)

Christopher T. Ruhland

2007-06-01

Full Text Available We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm on the maximum photochemical efficiency of photosystem II (Fv/Fm, bulk-soluble phenolic concentrations, ferric-reducing antioxidant power (FRAP and growth of Avena sativa. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B by either 71% (reduced UV-B or by 19% (near-ambient UV-B over the 52 day experiment (04 July - 25 August 2002. Plants growing under near-ambient UV-B had 38% less total biomass than those under reduced UV-B. The reduction in biomass was mainly the result of a 24% lower leaf elongation rate, resulting in shorter leaves and less total leaf area than plants under reduced UV-B. In addition, plants growing under near-ambient UV-B had up to 17% lower Fv/Fm values early in the experiment, and this effect declined with plant age. Concentrations of bulk-soluble phenolics and FRAP values were 17 and 24% higher under near-ambient UV-B than under reduced UV-B, respectively. There was a positive relationship between bulk-soluble phenolic concentrations and FRAP values. There were no UV-B effects on concentrations of carotenoids (carotenes + xanthophylls.

Use of expert systems in nuclear power plants

International Nuclear Information System (INIS)

Uhrig, R.E.

1989-01-01

The application of technologies, particularly expert systems, to the control room activities in a nuclear power plant has the potential to reduce operator error and increase plant safety, reliability, and efficiency. Furthermore, there are a large number of nonoperating activities (testing, routine maintenance, outage planning, equipment diagnostics, and fuel management) in which expert systems can increase the efficiency and effectiveness of overall plant and corporate operations. This document presents a number of potential applications of expert systems in the nuclear power field. 36 refs., 2 tabs

Activated charcoal and baking soda to reduce odor associated with extensive blistering disorders

Directory of Open Access Journals (Sweden)

Chakravarthi Arun

2008-01-01

Full Text Available Background: Skin disease leading to extensive blistering and loss of skin is associated with a characteristic smell. Odor can cause physiologic disturbances such as increase in heart rate and respiratory rate. It can also cause nausea and vomiting and is disturbing to bystanders. Aims: To test odor reducing capability of activated charcoal. Methods: In this blinded experimental study we used putrefied amniotic membrane to produce odor and studied the effectiveness of activated charcoal and soda-bi-carbonate to reduce odor. Results: Statistical analysis with Kruskal Wall′s Chi Square Test and Man Whitney U test showed significant reduction of odor using activated charcoal by itself or along with soda-bi-carbonate. Conclusion: We recommend the usage of activated charcoal with/without soda bicarbonate as an inexpensive practical measure to reduce foul odor associated with extensive skin loss.

Systematic review of active workplace interventions to reduce sickness absence

OpenAIRE

Odeen, Magnus; Magnussen, Liv Heide; Mæland, Silje; Larun, Lillebeth; Eriksen, Hege Randi; Tveito, Torill Helene

2013-01-01

Background: The workplace is used as a setting for interventions to prevent and reduce sickness absence, regardless of the specific medical conditions and diagnoses. Aims: To give an overview of the general effectiveness of active workplace interventions aimed at preventing and reducing sickness absence. Methods: We systematically searched PubMed, Embase, Psych-info, and ISI web of knowledge on 27 December 2011. Inclusion criteria were (i) participants over 18 years old with ...

Calculation of radioactive inventory of activated parts for nuclear power unit and analysis of influence factors

International Nuclear Information System (INIS)

Liu Yang; Cai Qi; Lin Xiaoling

2011-01-01

Based on the operation characteristics of the nuclear power unit, the radioactive inventory of activated parts was calculated by ORIGEN2, and the effects of bum-up, operation mode and power change on the radioactive inventory for activated parts were analyzed. The results indicated that the radioactive inventory grew with the increasing of burn-up, and when the actual operation time was longer than the effective operation time, the increasing rate of nuclide activity approximated the burn-up increasing; Radioactive inventory of activated parts was influenced directly by the operation modes of the nuclear power unit, and under same reactor load, operation power and bum-up, the radioactive inventory for non-continuous operation mode is less than that for the continuous operation mode. Effects of operation modes on radioactive inventory reversed with half life of nuclides. Under same bum-up and longer operation time, the effect of operation power change on the radioactive inventory is not obvious, (authors)

Core-shell LiFePO4 /carbon-coated reduced graphene oxide hybrids for high-power lithium-ion battery cathodes.

Science.gov (United States)

Ha, Sung Hoon; Lee, Yun Jung

2015-01-26

Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4 -rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4 , 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li(+) ion and electron transport for high power applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Use of Active Elements to Reduce the Size and Weight of Passive Components in Adjustable Speed Drives

DEFF Research Database (Denmark)

Maheshwari, Ram Krishan

the effectiveness of the new active damping method are presented. A Neutral-Point-Clamped (NPC) three-level inverter with small DC-link capacitors is selected as viable option for a two-level inverter in this thesis for low voltage applications. This inverter requires zero average neutral-point current for stable...... neutral-point potential. The small DC-link capacitors may not maintain the capacitor voltage balance even with zero neutral-point current due to nonlinearities present in the circuit. This requires a fast control of the neutral-point voltage. A simple carrier-based modulation strategy is proposed which......-link capacitor based drive system shows instability while it is operated with high input line inductance at the operating points with high power. This thesis presents a simple, new active damping technique that can stabilize effectively the drive system at the unstable operating points offering greatly reduced...

Methodology and conclusions of activation calculations of WWER-440 type nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Babcsány, Boglárka, E-mail: boglarka.babcsany@reak.bme.hu; Czifrus, Szabolcs; Fehér, Sándor

2015-04-01

Highlights: • Activation calculation of two WWER-440 type nuclear power plants. • Detailed description of the applied activation calculation methodology. • Graphical results for total activity and waste index categorization. • General conclusions for activation applicable in the case of PWR reactors. - Abstract: Activation calculations for two nuclear power plants of WWER-440 type have been performed by the authors in order to assist the decommissioning planning by assessing the radioactive inventory present at the time of and at different times after the final shutdown. According to related international literature and studies performed earlier by the authors, considering the activity more than 99% of this inventory is concentrated in the materials directly surrounding the reactor core, where the predominant evolution of radionuclides is generated by neutron induced nuclear reactions. In order to obtain the highest possible accuracy in modelling, three-dimensional Monte Carlo neutron transport calculations were performed. Besides the methods and models applied to these analyses, the paper also summarizes the results that can be generally applied to such nuclear power plant types. At the time of shutdown, the total activity of the stainless steel components is about 6 × 10{sup 16} Bq and 1.3 × 10{sup 17} Bq for the two NPPs considered. The biological shielding concrete constitutes approximately 7 × 10{sup 13} Bq and 1.1 × 10{sup 14} Bq.

Active Power Filter DC Bus Voltage Piecewise Reaching Law Variable Structure Control

OpenAIRE

Liu, Baolian; Ding, Zujun; Zhao, Huanyu; Jin, Defei

2014-01-01

The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF) operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the ...

Total phenolic content and in-vitro antioxidant activities from methanolic extract of alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

Digital Repository Service at National Institute of Oceanography (India)

Sanaye, S.V.; Pise, N.M.; Pawar, A.P.; Parab, P.P.; Sreepada, R.A.; Pawar, H.B.; Murugan, A.

-vitro antioxidant activities in terms of reducing power (RP), metal chelating activity (MCA), 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), inhibition of lipid peroxidation (LPX) and hydroxyl radical...

Digital Simulation of a Hybrid Active Filter - An Active Filter in Series with a Shunt Passive Filter

OpenAIRE

Sitaram, Mahesh I; Padiyar, KR; Ramanarayanan, V

1998-01-01

Active filters have long been in use for the filtering of power system load harmonics. In this paper, the digital simulation results of a hybrid active power filter system for a rectifier load are presented. The active filter is used for filtering higher order harmonics as the dominant harmonics are filtered by the passive filter. This reduces the rating of the active filter significantly. The DC capacitor voltage of the active filter is controlled using a PI controller.

Large roads reduce bat activity across multiple species.

Science.gov (United States)

Kitzes, Justin; Merenlender, Adina

2014-01-01

Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.

Evaluation of harmonic detection methods for active power filter applications

DEFF Research Database (Denmark)

Asiminoaei, Lucian; Blaabjerg, Frede; Hansen, Steffan

2005-01-01

In the attempt to minimize the harmonic disturbances created by the non-linear loads the choice of the active power filters comes out to improve the filtering efficiency and to solve many issues existing with classical passive filters. One of the key points for a proper implementation of an active...... theories. Then, the work here proposes a simulation setup that decouples the harmonic reference generator from the active filter model and its controller. In this way the selected methods can be equally analyzed and compared with respect to their performance, which helps anticipating possible...

Coordinated Volt/Var Control in Distribution Systems with Distributed Generations Based on Joint Active and Reactive Powers Dispatch

Directory of Open Access Journals (Sweden)

Abouzar Samimi

2016-01-01

Full Text Available One of the most significant control schemes in optimal operation of distribution networks is Volt/Var control (VVC. Owing to the radial structure of distribution systems and distribution lines with a small X/R ratio, the active power scheduling affects the VVC issue. A Distribution System Operator (DSO procures its active and reactive power requirements from Distributed Generations (DGs along with the wholesale electricity market. This paper proposes a new operational scheduling method based on a joint day-ahead active/reactive power market at the distribution level. To this end, based on the capability curve, a generic reactive power cost model for DGs is developed. The joint active/reactive power dispatch model presented in this paper motivates DGs to actively participate not only in the energy markets, but also in the VVC scheme through a competitive market. The proposed method which will be performed in an offline manner aims to optimally determine (i the scheduled active and reactive power values of generation units; (ii reactive power values of switched capacitor banks; and (iii tap positions of transformers for the next day. The joint active/reactive power dispatch model for daily VVC is modeled in GAMS and solved with the DICOPT solver. Finally, the plausibility of the proposed scheduling framework is examined on a typical 22-bus distribution test network over a 24-h period.

Power program and nuclear power

International Nuclear Information System (INIS)

Chernilin, Yu.F.

1990-01-01

Main points of the USSR power program and the role of nuclear power in fuel and power complex of the country are considered. Data on dynamics of economic indices of electric power generation at nuclear power plants during 1980-1988 and forecasts till 2000 are presented. It is shown that real cost of 1 kW/h of electric power is equal to 1.3-1.8 cop., and total reduced cost is equal to 1.8-2.4 cop

Power Quality Improvement in a Cascaded Multilevel Inverter Interfaced Grid Connected System Using a Modified Inductive–Capacitive–Inductive Filter with Reduced Power Loss and Improved Harmonic Attenuation

Directory of Open Access Journals (Sweden)

Meenakshi Jayaraman

2017-11-01

Full Text Available Recently, multilevel inverters are more researched due to the advantages they offer over conventional voltage source inverters in grid connected applications. Passive filters are connected at the output of these inverters to produce sinusoidal waveforms with reduced harmonics and to satisfy grid interconnection standard requirements. This work proposes a new passive filter topology for a pulse width modulated five-level cascaded inverter interfaced grid connected system. The proposed passive filter inserts an additional resistance-capacitance branch in parallel to the filter capacitor of the traditional inductive–capacitive–inductive filter in addition to a resistance in series with it to reduce damping power loss. It can attenuate the switching frequency harmonic current components much better than the traditional filter while maintaining the same overall inductance, reduced capacitance and resistance values. The basic parameter design procedure and an approach to discover the parameters of the proposed filter is introduced. Further, a novel methodology using Particle Swarm Optimization (PSO is recommended to guarantee minimum damping loss while ensuring reduced peak during resonance. In addition, PSO algorithm is newly employed in this work to maximize harmonic attenuation in and around the switching frequency on the premise of allowable values of filter inductance and capacitance. A comparative discussion considering traditional passive filters and the proposed filter is presented and evaluated through experiments conducted on a 110 V, 1 kW five-level grid connected inverter. The modulation algorithm for the multilevel inverter is implemented using a SPARTAN 6-XC6SLX25 Field Programmable Gate Array (FPGA processor. The analysis shows that the proposed filter not only provides decreased damping power loss but also is capable of providing considerable harmonic ripple reduction in the high frequency band, improved output waveforms and lesser

Constitutively active RAS signaling reduces 1,25 dihydroxyvitamin D-mediated gene transcription in intestinal epithelial cells by reducing vitamin D receptor expression.

Science.gov (United States)

DeSmet, Marsha L; Fleet, James C

2017-10-01

High vitamin D status is associated with reduced colon cancer risk but these studies ignore the diversity in the molecular etiology of colon cancer. RAS activating mutations are common in colon cancer and they activate pro-proliferative signaling pathways. We examined the impact of RAS activating mutations on 1,25 dihydroxyvitamin D (1,25(OH) 2 D)-mediated gene expression in cultured colon and intestinal cell lines. Transient transfection of Caco-2 cells with a constitutively active mutant K-RAS (G12 V) significantly reduced 1,25(OH) 2 D-induced activity of both a human 25-hydroxyvitamin D, 24 hydroxyase (CYP24A1) promoter-luciferase and an artificial 3X vitamin D response element (VDRE) promoter-luciferase reporter gene. Young Adult Mouse Colon (YAMC) and Rat Intestinal Epithelial (RIE) cell lines with stable expression of mutant H-RAS had suppressed 1,25(OH) 2 D-mediated induction of CYP24A1 mRNA. The RAS effects were associated with lower Vitamin D receptor (VDR) mRNA and protein levels in YAMC and RIE cells and they could be partially reversed by VDR overexpression. RAS-mediated suppression of VDR levels was not due to either reduced VDR mRNA stability or increased VDR gene methylation. However, chromatin accessibility to the VDR gene at the proximal promoter (-300bp), an enhancer region at -6kb, and an enhancer region located in exon 3 was significantly reduced in RAS transformed YAMC cells (YAMC-RAS). These data show that constitutively active RAS signaling suppresses 1,25(OH) 2 D-mediated gene transcription in colon epithelial cells by reducing VDR gene transcription but the mechanism for this suppression is not yet known. These data suggest that cancers with RAS-activating mutations may be less responsive to vitamin D mediated treatment or chemoprevention. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects.

Science.gov (United States)

Suggs, Jennifer A; Melkani, Girish C; Glasheen, Bernadette M; Detor, Mia M; Melkani, Anju; Marsan, Nathan P; Swank, Douglas M; Bernstein, Sanford I

2017-06-01

Individuals with inclusion body myopathy type 3 (IBM3) display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K) in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in decreased in vitro

A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects

Directory of Open Access Journals (Sweden)

Jennifer A. Suggs

2017-06-01

Full Text Available Individuals with inclusion body myopathy type 3 (IBM3 display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in

Architectural-level power estimation and experimentation

Science.gov (United States)

Ye, Wu

With the emergence of a plethora of embedded and portable applications and ever increasing integration levels, power dissipation of integrated circuits has moved to the forefront as a design constraint. Recent years have also seen a significant trend towards designs starting at the architectural (or RT) level. Those demand accurate yet fast RT level power estimation methodologies and tools. This thesis addresses issues and experiments associate with architectural level power estimation. An execution driven, cycle-accurate RT level power simulator, SimplePower, was developed using transition-sensitive energy models. It is based on the architecture of a five-stage pipelined RISC datapath for both 0.35mum and 0.8mum technology and can execute the integer subset of the instruction set of SimpleScalar . SimplePower measures the energy consumed in the datapath, memory and on-chip buses. During the development of SimplePower , a partitioning power modeling technique was proposed to model the energy consumed in complex functional units. The accuracy of this technique was validated with HSPICE simulation results for a register file and a shifter. A novel, selectively gated pipeline register optimization technique was proposed to reduce the datapath energy consumption. It uses the decoded control signals to selectively gate the data fields of the pipeline registers. Simulation results show that this technique can reduce the datapath energy consumption by 18--36% for a set of benchmarks. A low-level back-end compiler optimization, register relabeling, was applied to reduce the on-chip instruction cache data bus switch activities. Its impact was evaluated by SimplePower. Results show that it can reduce the energy consumed in the instruction data buses by 3.55--16.90%. A quantitative evaluation was conducted for the impact of six state-of-art high-level compilation techniques on both datapath and memory energy consumption. The experimental results provide a valuable insight for

Evidences of Reduced Antioxidant Activity in Patients With Chronic Migraine and Medication-Overuse Headache.

Science.gov (United States)

Lucchesi, Cinzia; Baldacci, Filippo; Cafalli, Martina; Chico, Lucia; Lo Gerfo, Annalisa; Bonuccelli, Ubaldo; Siciliano, Gabriele; Gori, Sara

2015-01-01

Migraine is a complex multifactorial, neurobiological disorder, whose pathogenesis is not fully understood, nor are the mechanisms associated with migraine transformation from episodic to chronic pattern. A possible role of impaired oxidative mitochondrial metabolism in migraine pathogenesis has been hypothesized, and increased levels of peripheral markers of oxidative stress have been reported in migraine patients, although the literature data are limited and heterogeneous. The aim of this cross-sectional study was to determine plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power and total plasmatic thiol groups, all plasmatic markers related to oxidative stress, in a sample of chronic migraine patients and medication-overuse headache, compared to a control group of healthy subjects. Thirty-three patients with a diagnosis of both chronic migraine and medication-overuse headache (International Classification of Headache Disorders,3rd edition, beta version) and 33 healthy, headache-free subjects were enrolled. Patients with comorbid/coexisting conditions were excluded, as well as patients in treatment with migraine preventive drugs. Plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power, and total thiol groups were determined in migraine patients and controls; moreover, oxidative stress biomarkers were compared in migraine patients with triptan compared to non-steroidal anti-inflammatory drug overuse. The statistical analysis showed significantly lower levels of ferric-reducing antioxidant power and total plasmatic thiol groups, both expression of antioxidant power, in patients with chronic migraine and medication-overuse headache compared to controls (respectively, ferric antioxidant power median [interquartile range] 0.53 [0.22] vs 0.82 [0.11] mmol/L, P stress biomarkers were detected between patients with triptan and nonsteroidal anti-inflammatory drug overuse. The data from the present

A study of overseas research activities for thorium reactors and the need for the introduction of the domestic nuclear power

Energy Technology Data Exchange (ETDEWEB)

Park, Dongwon; Park, Keunteag [Korea Inspection Co., Seoul (Korea, Republic of)

2013-05-15

Many countries have been proceeding research actively in this area as highlighted these advantages but de facto, there are not official research activities in Korea. This paper is to analyze the current status of research in some countries and describe the possibilities introduce with necessity in Korea. Radiation and the radioactive waste, decay heat, loss of coolant accident that related with safety issue are always emerging as a problem of social acceptance of nuclear power plant. Proportion of U-{sub 235}, uranium fuel is only 3-5% and the rest of U-{sub 238} is discarded as all nuclear waste in accordance with 'Open Cycle.' Even if put to practical use thorium reactor, nuclear waste generated but can significantly reduce the toxicity nuclides of TRU and not only the decay heat that physical cause of Fukushima nuclear power plant accident does not occur but also do not need to worry about the LOCA. Our nuclear power plant have been operated very safety compared to Japan. Relative to unexpected operation stop status in terms of base 5 years previous of Fukushima nuclear accident are 0.5 based on average value in our nuclear power plants on the other hand 0.4 in total 17 units of nuclear power plant subsidiary Tokyo Electric Power co., Japan. It is similar to ours, and is similar to Kansai Electric Power Co. However, total reported incidents of non-severe accidents are much higher than ours. But that cannot be interpreted as the safety of our operating skills of nuclear power plant are excellent compared to other countries. For many people's anxiety about nuclear power plants operating after the Fukushima accident, nuclear operators emphasized the safety of our nuclear power plant with referring to the difference between PWR and BWR. Our nuclear power plant were complementary in many facilities depend on problems revealed at the Fukushima nuclear power plant. But it seems to be need for long-term research and development of next-generation nuclear

Active Photonic crystal fibers for high power applications

DEFF Research Database (Denmark)

Olausson, Christina Bjarnal Thulin

The photonic crystal ber technology provides means to realize bers optimized for high power operation, due to the large single-mode cores and the unique design exibility of the microstructure. The work presented in this thesis focuses on improving the properties of active photonic crystal bers...... contributed to the compounding of new and improved material compositions. The second part is an investigation of pump absorption in photonic crystal bers, demonstrating that the microstructure in photonic crystal bers improves the pump absorption by up to a factor of two compared to step-index bers....... This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential...

Comprehensive Power Losses Model for Electronic Power Transformer

DEFF Research Database (Denmark)

Yue, Quanyou; Li, Canbing; Cao, Yijia

2018-01-01

and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self-losses......The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...

Comprehensive Power Losses Model for Electronic Power Transformer

DEFF Research Database (Denmark)

Yue, Quanyou; Li, Canbing; Cao, Yijia

2018-01-01

The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self......-losses and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...