WorldWideScience

Sample records for current control strategies

  1. Malaria vector control: current and future strategies

    NARCIS (Netherlands)

    Takken, W.; Knols, B.G.J.

    2009-01-01

    The recently announced call for malaria eradication represents a new page in the history of this disease. This has been triggered by remarkable reductions in malaria resulting from combined application of effective drugs and vector control. However, this strategy is threatened by development of

  2. Discrete Current Control Strategy of Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Yan Dong

    2013-01-01

    Full Text Available A control strategy of permanent magnet synchronous motors (PMSMs, which is different from the traditional vector control (VC and direct torque control (DTC, is proposed. Firstly, the circular rotating magnetic field is analyzed on the simplified model and discredited into stepping magnetic field. The stepping magnetomotive force will drive the rotor to run as the stepping motor. Secondly, the stator current orientation is used to build the control model instead of rotor flux orientation. Then, the discrete current control strategy is set and adopted in positioning control. Three methods of the strategy are simulated in computer and tested on the experiment platform of PMSM. The control precision is also verified through the experiment.

  3. Steam generator degradation: Current mitigation strategies for controlling corrosion

    International Nuclear Information System (INIS)

    Millett, P.

    1997-01-01

    Steam Generator degradation has caused substantial losses of power generation, resulted in large repair and maintenance costs, and contributed to significant personnel radiation exposures in Pressurized Water Reactors (PWRs) operating throughout the world. EPRI has just published the revised Steam Generator Reference Book, which reviews all of the major forms of SG degradation. This paper discusses the types of SG degradation that have been experienced with emphasis on the mitigation strategies that have been developed and implemented in the field. SG degradation is presented from a world wide perspective as all countries operating PWRs have been effected to one degree or another. The paper is written from a US. perspective where the utility industry is currently undergoing tremendous change as a result of deregulation of the electricity marketplace. Competitive pressures are causing utilities to strive to reduce Operations and Maintenance (O ampersand M) and capital costs. SG corrosion is a major contributor to the O ampersand M costs of PWR plants, and therefore US utilities are evaluating and implementing the most cost effective solutions to their corrosion problems. Mitigation strategies developed over the past few years reflect a trend towards plant specific solutions to SG corrosion problems. Since SG degradation is in most cases an economic problem and not a safety problem, utilities can focus their mitigation strategies on their unique financial situation. Accordingly, the focus of R ampersand D has shifted from the development of more expensive, prescriptive solutions (e.g. reduced impurity limits) to corrosion problems to providing the utilities with a number of cost effective mitigation options (e.g. molar ratio control, boric acid treatment)

  4. A Harmonic Current Suppression Control Strategy for Droop-Controlled Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Wei, Feng; Sun, Kai; Guan, Yajuan

    2015-01-01

    currents. Therefore, the reason of generation of distorted grid-feeding current of GF-VCI under the distorted grid voltage is investigated firstly in this paper. Then, a harmonic grid-feeding current suppression control strategy for GF-VCI is proposed. Two different filters are compared and analysed before...... voltage component at the point of common coupling. As a result, the difference of harmonic voltage between PCC and GF-VCI is reduced and the THDi of grid feeding-currents is decreased. Finally, the proposed control strategy is verified through simulations and experimental results....

  5. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  6. Improved control strategy for PI-R current of DFIG considering voltage and current harmonics compensation

    Science.gov (United States)

    Song, S. Y.; Liu, Q. H.; Zhao, Y. N.; Liu, S. Y.

    2016-08-01

    With the rapid development of wind power generation, the related research of wind power control and integration issues has attracted much attention, and the focus of the research are shifting away from the ideal power grid environment to the actual power grid environment. As the main stream wind turbine generator, a doubly-fed induction generator (DFIG) is connected to the power grid directly by its stator, so it is particularly sensitive to the power grid. This paper studies the improvement of DFIG control technology in the power grid harmonic environment. Based on the DFIG dynamic model considering the power grid harmonic environment, this paper introduces the shortcomings of the common control strategy of DFIG, and puts forward the enhanced method. The decoupling control of the system is realized by compensating the coupling between the rotor harmonic voltage and harmonic current, improving the control performance. In addition, the simulation experiments on PSCAD/EMTDC are carried out to verify the correctness and effectiveness of the improved scheme.

  7. Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2016-12-01

    Full Text Available This paper proposes a balanced current control strategy for the current source rectifier (CSR stage of an indirect matrix converter (IMC under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the proposed control strategy under unbalanced grid voltage conditions, the stability and life span of the overall system can be improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

  8. A DC Microgrid Coordinated Control Strategy Based on Integrator Current-Sharing

    DEFF Research Database (Denmark)

    Gao, Liyuan; Liu, Yao; Ren, Huisong

    2017-01-01

    The DC microgrid has become a new trend for microgrid study with the advantages of high reliability, simple control and low losses. With regard to the drawbacks of the traditional droop control strategies, an improved DC droop control strategy based on integrator current-sharing is introduced....... In the strategy, the principle of eliminating deviation through an integrator is used, constructing the current-sharing term in order to make the power-sharing between different distributed generation (DG) units uniform and reasonable, which can reduce the circulating current between DG units. Furthermore......, at the system coordinated control level, a hierarchical/droop control strategy based on the DC bus voltage is proposed. In the strategy, the operation modes of the AC main network and micro-sources are determined through detecting the DC voltage variation, which can ensure the power balance of the DC microgrid...

  9. A Coordinate Control Strategy for Circulating Current Suppression in Multiparalleled Three-Phase Inverters

    DEFF Research Database (Denmark)

    Zhang, Xueguang; Wang, Tianyi; Wang, Xiongfei

    2017-01-01

    This paper addresses the zero-sequence circulating current control in the multiparalleled three-phase voltage-source inverters. The model of the zero-sequence circulating current in the N-paralleled (N ≥ 3) inverters is derived. It is shown that the circulating current is not only susceptible...... to the mismatches of circuit parameters, but it is also influenced by the interactions of circulating current controllers used by other paralleled inverters. To eliminate these adverse effects on the circulating current control loop, a coordinate control strategy for the N-paralleled inverter is proposed based...... on the zero-vector feedforward method with the space-vector pulse width modulation. Moreover, a virtual inverter method is introduced to facilitate the implementation of the proposed controller, which decouples the interactions of circulating current controllers in the paralleled inverters. Finally...

  10. A DC Microgrid Coordinated Control Strategy Based on Integrator Current-Sharing

    Directory of Open Access Journals (Sweden)

    Liyuan Gao

    2017-08-01

    Full Text Available The DC microgrid has become a new trend for microgrid study with the advantages of high reliability, simple control and low losses. With regard to the drawbacks of the traditional droop control strategies, an improved DC droop control strategy based on integrator current-sharing is introduced. In the strategy, the principle of eliminating deviation through an integrator is used, constructing the current-sharing term in order to make the power-sharing between different distributed generation (DG units uniform and reasonable, which can reduce the circulating current between DG units. Furthermore, at the system coordinated control level, a hierarchical/droop control strategy based on the DC bus voltage is proposed. In the strategy, the operation modes of the AC main network and micro-sources are determined through detecting the DC voltage variation, which can ensure the power balance of the DC microgrid under different operating conditions. Meanwhile, communication is not needed between different DG units, while each DG unit needs to sample the DC bus voltage, which retains the plug-and-play feature of the DC microgrid. The proposed control strategy is validated by simulation on a DC microgrid with permanent magnet synchronous generator-based wind turbines, solar arrays and energy storage batteries, which can be applied to small commercial or residential buildings.

  11. A fault-tolerant strategy based on SMC for current-controlled converters

    Science.gov (United States)

    Azer, Peter M.; Marei, Mostafa I.; Sattar, Ahmed A.

    2018-05-01

    The sliding mode control (SMC) is used to control variable structure systems such as power electronics converters. This paper presents a fault-tolerant strategy based on the SMC for current-controlled AC-DC converters. The proposed SMC is based on three sliding surfaces for the three legs of the AC-DC converter. Two sliding surfaces are assigned to control the phase currents since the input three-phase currents are balanced. Hence, the third sliding surface is considered as an extra degree of freedom which is utilised to control the neutral voltage. This action is utilised to enhance the performance of the converter during open-switch faults. The proposed fault-tolerant strategy is based on allocating the sliding surface of the faulty leg to control the neutral voltage. Consequently, the current waveform is improved. The behaviour of the current-controlled converter during different types of open-switch faults is analysed. Double switch faults include three cases: two upper switch fault; upper and lower switch fault at different legs; and two switches of the same leg. The dynamic performance of the proposed system is evaluated during healthy and open-switch fault operations. Simulation results exhibit the various merits of the proposed SMC-based fault-tolerant strategy.

  12. A novel harmonic current sharing control strategy for parallel-connected inverters

    DEFF Research Database (Denmark)

    Guan, Yajuan; Guerrero, Josep M.; Savaghebi, Mehdi

    2017-01-01

    A novel control strategy which enables proportional linear and nonlinear loads sharing among paralleled inverters and voltage harmonic suppression is proposed in this paper. The proposed method is based on the autonomous currents sharing controller (ACSC) instead of conventional power droop control...... to provide fast transient response, decoupling control and large stability margin. The current components at different sequences and orders are decomposed by a multi-second-order generalized integrator-based frequency locked loop (MSOGI-FLL). A harmonic-orthogonal-virtual-resistances controller (HOVR......) is used to proportionally share current components at different sequences and orders independently among the paralleled inverters. Proportional resonance controllers tuned at selected frequencies are used to suppress voltage harmonics. Simulations based on two 2.2 kW paralleled three-phase inverters...

  13. Zero-Axis Virtual Synchronous Coordinate Based Current Control Strategy for Grid-Connected Inverter

    Directory of Open Access Journals (Sweden)

    Longyue Yang

    2018-05-01

    Full Text Available Unbalanced power has a great influence on the safe and stable operation of the distribution network system. The static power compensator, which is essentially a grid-connected inverter, is an effective solution to the three-phase power imbalance problem. In order to solve the tracking error problem of zero-sequence AC current signals, a novel control strategy based on zero-axis virtual synchronous coordinates is proposed in this paper. By configuring the operation of filter transmission matrices, a specific orthogonal signal is obtained for zero-axis reconstruction. In addition, a controller design scheme based on this method is proposed. Compared with the traditional zero-axis direct control, this control strategy is equivalent to adding a frequency tuning module by the orthogonal signal generator. The control gain of an open loop system can be equivalently promoted through linear transformation. With its clear mathematical meaning, zero- sequence current control can be controlled with only a first-order linear controller. Through reasonable parameter design, zero steady-state error, fast response and strong stability can be achieved. Finally, the performance of the proposed control strategy is verified by both simulations and experiments.

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

    Directory of Open Access Journals (Sweden)

    NAMMALVAR, P.

    2018-02-01

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

  15. Current strategy for leprosy control in Brazil: time to pursue alternative preventive strategies?

    OpenAIRE

    Sérgio S. Cunha; Laura C. Rodrigues; Nádia Cristina Duppre

    2004-01-01

    La estrategia actual para el control de la lepra en Brasil se basa en dos actividades principales: la detección precoz de casos y el tratamiento de casos con farmacoterapia combinada. Además de dichas medidas, se realizan esfuerzos complementarios para identificar los contactos domésticos para el diagnóstico precoz y la vacunación con el bacilo de Calmette-Guérin (BCG). Sin embargo, la eficacia de estas acciones a la hora de reducir la incidencia de la lepra es aún discutible. Esto genera dud...

  16. Current status and strategies for the control of viral hepatitis A in Korea.

    Science.gov (United States)

    Yoon, Eileen L; Sinn, Dong Hyun; Lee, Hyun Woong; Kim, Ji Hoon

    2017-09-01

    Hepatitis A virus is one of the most frequent causes of foodborne infection, which is closely associated with sanitary conditions and hygienic practices. The clinical spectrum of acute hepatitis A is wide, ranging from mild case without any noticeable symptoms to severe case with acute liver failure leading to mortality. The severity and outcome are highly correlated with age at infection. In developing countries, most people are infected in early childhood without significant symptom. Ironically, in area where sanitary condition has improved rapidly, adults who do not have immunity for viral hepatitis A (VH-A) in early childhood is accumulating. Adults without immunity are exposed to risks of symptomatic disease and large outbreaks in society. In Korea, where hygiene has improved rapidly, acute hepatitis A is a significant health burden that needs to be managed with nationwide health policy. The incidence of symptomatic VH-A has increased since 2000 and peaked in 2009. Korea has designated hepatitis A as a group 1 nationally notifiable infectious disease in 2001. Since 2001, mandatory surveillance system has been established to detect every single case of acute hepatitis A. Universal, nationwide vaccination program for newborns was introduced in 2015. In this review, we will present the current epidemiologic status of viral hepatitis A, and evaluate the effectiveness of the current nationwide strategies for the control of viral hepatitis A in Korea. Furthermore, we presented some action proposals that can help eliminate viral hepatitis A, which is a significant health burden in Korea.

  17. Current Status of Air Toxics Management and Its Strategies for Controlling Emissions in Taiwan

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2016-04-01

    Full Text Available Since the 1970s, hazardous air pollutants (HAPs, so-called air toxics, have been of great concern because they can cause serious human health effects and have adverse effects on the environment. More noticeably, some of them are known to be human carcinogens. The objective of this paper is to investigate the regulatory systems and human health effects of air toxics which have been designated by the Taiwan government under the Air Pollution Control Act. These toxic air pollutants include acutely toxic gas (i.e., ammonia, chlorine, fluorides, hydrochloric acid, hydrogen cyanide, hydrogen sulfide, nitric acid, phosphoric acid and sulfuric acid, gas containing heavy metals, and carcinogenic chemicals (including formaldehyde, vinyl chloride, asbestos and matter containing asbestos, dioxins and furans, volatile organic compounds, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. In line with international concern about the carcinogenic risk and environmental persistence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs and heavy metals in recent years, the current status in monitoring and reducing the emissions of PCDDs/PCDFs from stationary sources was analyzed as a case study in the present study. Furthermore, the control strategies for reducing emissions of air toxics from stationary sources in Taiwan were also addressed.

  18. A ZVS PWM control strategy with balanced capacitor current for half-bridge three-level DC/DC converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    2017-01-01

    The capacitor current would be imbalanced under the conventional control strategy in the half-bridge three-level (HBTL) DC/DC converter due to the effect of the output inductance of the power supply and the input line inductance, which would affect the converter's reliability. This paper proposes...... a pulse-wide modulation (PWM) strategy composed of two operation modes for the HBTL DC/DC converter, which can realize the zero-voltage switching (ZVS) for the efficiency improvement. In addition, a capacitor current balancing control is proposed by alternating the two operation modes of the proposed ZVS...... PWM strategy, which can eliminate the current imbalance among the two input capacitors. Therefore, the proposed control strategy can improve the converter's performance and reliability in: 1) reducing the switching losses and noises of the power switches; 2) balancing the thermal stresses...

  19. Analysis and Design of Improved Weighted Average Current Control Strategy for LCL-Type Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Yang, Ping

    2017-01-01

    The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid...... Control Strategy for LCL-Type Grid-Connected Inverters. Available from: https://www.researchgate.net/publication/313734269_Analysis_and_Design_of_Improved_Weighted_Average_Current_Control_Strategy_for_LCL-Type_Grid-Connected_Inverters [accessed Apr 20, 2017]....... current plus capacitor current feedback system is widely used for its better transient response and high robustness against the grid impedance variations. While the weighted average current (WAC) feedback scheme is capable to provide a wider bandwidth at higher frequencies but show poor stability...

  20. Instantaneous Project Controls: Current Status, State of the Art, Benefits, and Strategies

    Science.gov (United States)

    Abbaszadegan, Amin

    2016-01-01

    Despite advancements in construction and construction-related technology, capital project performance deviations, typically overruns, remain endemic within the capital projects industry. Currently, management is generally unaware of the current status of their projects, and thus monitoring and control of projects are not achieved effectively. In…

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

    DEFF Research Database (Denmark)

    Lu, Jinghang; Guan, Yajuan; Savaghebi, Mehdi

    2017-01-01

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

  2. Novel Differential Current Control Strategy Based on a Modified Three-Level SVPWM for Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Zorig, Abdelmalik; Barkat, Said; Belkheiri, Mohammed

    2017-01-01

    Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation. The distr......Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation....... The distribution of switching vectors of the resulting multilevel topology has a certain degree of self-differential current balancing properties. Nevertheless, the method alone is not sufficient to maintain balanced differential current in practical applications. This paper proposes a closed-loop differential...... current control method by introducing a control variable adjusting the dwell time of the selected switching vectors and thus maintaining the differential currents balanced without affecting the overall system performance. The control strategy, including distribution of switching sequence, selection...

  3. Simulation and RTDS Hardware Implementation of SHAF for Mitigation of Current Harmonics with p-q and Id-Iq Control Strategies Using PI Controller

    Directory of Open Access Journals (Sweden)

    A. K. Panda

    2011-06-01

    Full Text Available Control strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source conditions in MATLAB/Simulink environment and also with Real Time Digital Simulator (RTDS Hardware. When the supply voltages are balanced and sinusoidal, the two control strategies are converging to the same compensation characteristics but when the supply voltages are distorted and/or un-balanced sinusoidal, these control strategies result in different degrees of compensation in harmonics. The p-q control strategy is unable to yield an adequate solution when source voltages are not ideal. Extensive Simulations are carried out with PI controller for both p-q and Id-Iq control strategies for different voltage conditions and adequate results were presented. The 3-ph 4-wire SHAF system is also implemented on RTDS Hardware to further verify its effectiveness. The detailed simulation and RTDS Hardware results are included.

  4. Control Strategy for Three-Phase Grid-Connected PV Inverters Enabling Current Limitation Under Unbalanced Faults

    DEFF Research Database (Denmark)

    Afshari, Ehsan; Moradi, Gholam Reza; Rahimi, Ramin

    2017-01-01

    Power quality and voltage control are among the most important aspects of the grid-connected power converter operation under faults. Non-sinusoidal current is injected during unbalanced voltage sag and active or/and reactive power includes double frequency content. This paper introduces a novel...... control strategy to mitigate the double grid frequency oscillations in the active power and dc-link voltage of the two-stage three-phase grid-connected Photovoltaic (PV) inverters during unbalanced faults. With the proposed control method, PV inverter injects sinusoidal currents under unbalanced grid...... faults. In addition, an efficient and easy-to-implement current limitation method is introduced, which can effectively limit the injected currents to the rated value during faults. In this case, the fault-ride-through operation is ensured and it will not trigger the overcurrent protection. A non...

  5. An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2015-07-01

    Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary  frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

  6. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  7. A review of current strategy for rabies prevention and control in the developing world

    Directory of Open Access Journals (Sweden)

    Suneela Garg

    2017-03-01

    Full Text Available The control of Rabies, a zoonotic viral disease is a major public challenge in several developing countries. Current approaches for rabies control are overwhelmingly directed towards provision of effective post exposure prophylaxis (PEP to animal bite victims. The enormous costs involved in rabies prophylaxis is an important factor precluding its universal application in all animal bite victims especially in those residing in resource constrained settings. The intradermal route of administration has been shown to be cost effective except in peripheral regions with fewer animal bite cases. Nevertheless, rabies control program with their expected emphasis on human rabies prophylaxis have neglected canine vaccination. The feasibility of canine rabies vaccination depends primarily upon allocation of resources through political commitment and effective public private partnerships. However, in large parts of the world including India formal dog ownership constitutes a small minority of the overall canine population while state funded canine vaccination drives often fail to impress policy makers who struggle to maintain budgets for adequate coverage of rabies PEP for animal bite victims. The key to rabies control may therefore rest upon a one health approach with development of newer vaccine technology which is cost effective for vaccination in both, man and animal.

  8. Control Strategies for Islanded Microgrid using Enhanced Hierarchical Control Structure with Multiple Current-Loop Damping Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Zhao, Xin

    2017-01-01

    In this paper, the modeling, controller design, and stability analysis of the islanded microgrid (MG) using enhanced hierarchical control structure with multiple current loop damping schemes is proposed. The islanded MG is consisted of the parallel-connected voltage source inverters using LCL...... output filters, and the proposed control structure includes: the primary control with additional phase-shift loop, the secondary control for voltage amplitude and frequency restoration, the virtual impedance loops which contains virtual positive- and negative-sequence impedance loops at fundamental...... frequency, and virtual variable harmonic impedance loop at harmonic frequencies, and the inner voltage and current loop controllers. A small-signal model for the primary and secondary controls with additional phase-shift loop is presented, which shows an over-damped feature from eigenvalue analysis...

  9. Elicitors as alternative strategy to pesticides in grapevine? Current knowledge on their mode of action from controlled conditions to vineyard.

    Science.gov (United States)

    Delaunois, Bertrand; Farace, Giovanni; Jeandet, Philippe; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan; Cordelier, Sylvain

    2014-04-01

    Development and optimisation of alternative strategies to reduce the use of classic chemical inputs for protection against diseases in vineyard is becoming a necessity. Among these strategies, one of the most promising consists in the stimulation and/or potentiation of the grapevine defence responses by the means of elicitors. Elicitors are highly diverse molecules both in nature and origins. This review aims at providing an overview of the current knowledge on these molecules and will highlight their potential efficacy from the laboratory in controlled conditions to vineyards. Recent findings and concepts (especially on plant innate immunity) and the new terminology (microbe-associated molecular patterns, effectors, etc.) are also discussed in this context. Other objectives of this review are to highlight the difficulty of transferring elicitors use and results from the controlled conditions to the vineyard, to determine their practical and effective use in viticulture and to propose ideas for improving their efficacy in non-controlled conditions.

  10. [Whooping cough in Spain. Current epidemiology, prevention and control strategies. Recommendations by the Pertussis Working Group].

    Science.gov (United States)

    Campins, Magda; Moreno-Pérez, David; Gil-de Miguel, Angel; González-Romo, Fernando; Moraga-Llop, Fernando A; Arístegui-Fernández, Javier; Goncé-Mellgren, Anna; Bayas, José M; Salleras-Sanmartí, Lluís

    2013-04-01

    A large increase of pertussis incidence has been observed in recent years in countries with high vaccination coverage. Outbreaks of pertussis are increasingly being reported. The age presentation has a bipolar distribution: infants younger 6months that have not initiated or completed a vaccination schedule, and adolescents and adults, due to the lost of natural or vaccine immunity over time. These epidemiological changes justify the need to adopt new vaccination strategies in order to protect young infants and to reduce pertussis incidence in all age groups. Adolescents and adults immunization must be a priority. In the first group, strategy is easy to implement, and with a very low additional cost (to replace dT vaccine by dTap one). Adult vaccination may be more difficult to implement; dT vaccine decennial booster should be replaced by dTap. The immunization of household contacts of newborn infants (cocooning) is the strategy that has a most important impact on infant pertussis. Recently, pregnant women vaccination (after 20weeks of gestation) has been recommended in some countries as the most effective way to protect the newborn. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  11. A Voltage Feedback Based Harmonic Compensation Strategy for Current-Controlled Converters

    DEFF Research Database (Denmark)

    Zhao, Xin; Meng, Lexuan; Xie, Chuan

    2018-01-01

    Harmonics have been considered as one of the major issues in future power grids. With the increasing demand in advanced control functions, power electronic converter interfaced distributed generators (DGs) are expected to perform harmonic compensation when necessary. It has been demonstrated in a...

  12. Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies.

    Directory of Open Access Journals (Sweden)

    Craig S Fryer

    Full Text Available Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology.Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12-25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research.We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs.The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults.

  13. Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies.

    Science.gov (United States)

    Fryer, Craig S; Seaman, Elizabeth L; Clark, Rachael S; Plano Clark, Vicki L

    2017-01-01

    Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology. Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12-25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research. We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs. The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults.

  14. Prevention and Control Strategies to Counter Zika Virus, a Special Focus on Intervention Approaches against Vector Mosquitoes—Current Updates

    Directory of Open Access Journals (Sweden)

    Raj K. Singh

    2018-02-01

    Full Text Available Zika virus (ZIKV is the most recent intruder that acquired the status of global threat creating panic and frightening situation to public owing to its rapid spread, attaining higher virulence and causing complex clinical manifestations including microcephaly in newborns and Guillain Barré Syndrome. Alike other flaviviruses, the principal mode of ZIKV transmission is by mosquitoes. Advances in research have provided reliable diagnostics for detecting ZIKV infection, while several drug/therapeutic targets and vaccine candidates have been identified recently. Despite these progresses, currently there is neither any effective drug nor any vaccine available against ZIKV. Under such circumstances and to tackle the problem at large, control measures of which mosquito population control need to be strengthened following appropriate mechanical, chemical, biological and genetic control measures. Apart from this, several other known modes of ZIKV transmission which have gained importance in recent past such as intrauterine, sexual intercourse, and blood-borne spread need to be checked and kept under control by adopting appropriate precautions and utmost care during sexual intercourse, blood transfusion and organ transplantation. The virus inactivation by pasteurization, detergents, chemicals, and filtration can effectively reduce viral load in plasma-derived medicinal products. Added to this, strengthening of the surveillance and monitoring of ZIKV as well as avoiding travel to Zika infected areas would aid in keeping viral infection under check. Here, we discuss the salient advances in the prevention and control strategies to combat ZIKV with a focus on highlighting various intervention approaches against the vector mosquitoes of this viral pathogen along with presenting an overview regarding human intervention measures to counter other modes of ZIKV transmission and spread. Additionally, owing to the success of vaccines for a number of infections

  15. Input-Parallel Output-Parallel Three-Level DC/DC Converters With Interleaving Control Strategy for Minimizing and Balancing Capacitor Ripple Currents

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Gong, Zheng

    2017-01-01

    In this paper, the input-parallel output-parallel (IPOP) three-level (TL) DC/DC converters associated with the interleaving control strategy are proposed for minimizing and balancing the capacitor ripple currents. The proposed converters consist of two four-switch half-bridge three-level (HBTL) DC...

  16. Abc-frame complex-coefficient filter and controller based current harmonic elimination strategy for three-phase grid connected inverter

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected...... inverter. Different from the traditional method, our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical...

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  18. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions....... It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method...... is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed...

  19. Supervisory Control Strategy Development

    International Nuclear Information System (INIS)

    Gary D Storrick; Bojan Petrovic

    2007-01-01

    Task 4 of this collaborative effort between ORNL, Brazil, and Westinghouse for the International Nuclear Energy Research Initiative entitled 'Development of Advanced Instrumentation and Control for an Integrated Primary System Reactor' focused on the design of the hierarchical supervisory control for multiple-module units. The state of the IRIS plant design--specifically, the lack of a detailed secondary system design--made developing a detailed hierarchical control difficult at this time. However, other simultaneous and ongoing efforts have contributed to providing the needed information. This report summarizes the results achieved under Task 4 of this Financial Assistance Award. Section 1.2 describes the scope of this effort. Section 2 discusses the IRIS control functions. Next, it briefly reviews the current control concepts, and then reviews the maneuvering requirements for the IRIS plant. It closes by noting the benefits that automated sequences have in reducing operator workload. Section 3 examines reactor loading in the frequency domain to establish some guidelines for module operation, paying particular attention to strategies for using process steam for desalination and/or district heating. The final subsection discusses the implications for reactor control, and argues that using the envisioned percentage (up to 10%) of the NSSS thermal output for these purposes should not significantly affect the NSSS control strategies. Section 4 uses some very general economic assumptions to suggest how one should approach multi-module operation. It concludes that the well-known algorithms used for economic dispatching could be used to help manage a multi-unit IRIS site. Section 5 addresses the human performance factors of multi-module operation. Section 6 summarizes our conclusions

  20. Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

    Directory of Open Access Journals (Sweden)

    N. Belhaouchet

    2008-03-01

    Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.

  1. Prostate carcinoma: current diagnostic strategy

    International Nuclear Information System (INIS)

    Schwarzschild, Monica Maria Agata Stiepcich; Ferraz, Maria Lucia Cardoso Gomes; Oliveira, Jose Marcelo Amatuzzi; Andriolo, Adagmar

    2001-01-01

    Prostate cancer is the second cause of cancer death in men in the Western world. Despite progress in the treatment of advanced disease, it is recognized that the only possibility of reduction in prostate cancer death is nearly diagnosis when the disease is localized. In the present study our aim was to review the current strategy for diagnosis of prostate carcinoma. Prostate-specific antigen (PSA) is a valuable tumor marker and has demonstrated effectiveness in detecting prostate carcinoma, monitoring therapeutic efficacy, and disclosing disease recurrence. However, alternative methods are been proposed just as the free to total PSA ratio, PSA density, PSA velocity, which could improve the diagnostic sensibility and the specificity. Image diagnostic methods include transrectal ultra sound, computerized tomography, magnetic resonance image, and bone cintigraphy. The ultra sound is the best approach to guide the prostate biopsy and, together with the magnetic resonance is still useful for loco regional graduation. Computerized tomography as magnetic resonance image can be used for identification of linfonodal involvement. Bone cintigraphy is the best method for the identification of metastatic disease. (author)

  2. Fowl adenovirus-induced diseases and strategies for their control - a review on the current global situation.

    Science.gov (United States)

    Schachner, Anna; Matos, Miguel; Grafl, Beatrice; Hess, Michael

    2018-04-01

    The stand-alone pathogenicity of fowl adenoviruses (FAdVs) had long been disputed, given the ubiquity of the viruses versus sporadic outbreaks, and variation between experimental studies. However, a globally emerging trend of FAdV-associated diseases has marked the past two decades, with hepatitis-hydropericardium syndrome mainly in Asia besides Arabian and Latin American countries, and geographically more disseminated outbreaks of inclusion body hepatitis. Finally, the appearance of FAdV-induced gizzard erosion (AGE) in Asia and Europe completed the range of diseases. Epidemiological studies confirmed serotype FAdV-4 as agent of hepatitis-hydropericardium syndrome, whereas inclusion body hepatitis is related to FAdV-2, -8a, -8b and -11. Members of the biologically more distant serotype FAdV-1 induce AGE. Urged by increasing problems in the field, numerous pathogenicity studies with FAdVs from outbreaks substantiated the primary aetiologic role of particular strains for distinct clinical conditions. Developments in the poultry industry towards highly specialized genetic breeds and rigorous biosecurity additionally contribute to the growing incidence of FAdV-related diseases. Confirming field observations, recent studies connected a higher susceptibility of broilers with their distinct physiology, implying the choice of bird type as a factor to be considered in infection studies. Furthermore, elevated biosecurity standards have generated immunologically naïve breeding stocks, putting broilers at risk in face of vertical FAdV transmission. Therefore, future prevention strategies should include adequate antibodies in breeders prior to production and - if necessary - vaccination, in order to protect progenies. This review aims to deliver a detailed overview on the current global situation about FAdV-induced diseases, their reproduction in vivo and vaccination strategies.

  3. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

  4. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

  5. CMOS current controlled fully balanced current conveyor

    International Nuclear Information System (INIS)

    Wang Chunhua; Zhang Qiujing; Liu Haiguang

    2009-01-01

    This paper presents a current controlled fully balanced second-generation current conveyor circuit (CF-BCCII). The proposed circuit has the traits of fully balanced architecture, and its X-Y terminals are current controllable. Based on the CFBCCII, two biquadratic universal filters are also proposed as its applications. The CFBCCII circuits and the two filters were fabricated with chartered 0.35-μm CMOS technology; with ±1.65 V power supply voltage, the total power consumption of the CFBCCII circuit is 3.6 mW. Comparisons between measured and HSpice simulation results are also given.

  6. BWR control blade replacement strategies

    Energy Technology Data Exchange (ETDEWEB)

    Kennard, M W [Stoller Nuclear Fuel, NAC International, Pleasantville, NY (United States); Harbottle, J E [Stoller Nuclear Fuel, NAC International, Thornbury, Bristol (United Kingdom)

    2000-02-01

    The reactivity control elements in a BWR, the control blades, perform three significant functions: provide shutdown margin during normal and accident operating conditions; provide overall core reactivity control; and provide axial power shaping control. As such, the blades are exposed to the core's neutron flux, resulting in irradiation of blade structural and absorber materials. Since the absorber depletes with time (if B{sub 4}C is used, it also swells) and the structural components undergo various degradation mechanisms (e.g., embrittlement, corrosion), the blades have limits on their operational lifetimes. Consequently, BWR utilities have implemented strategies that aim to maximize blade lifetimes while balancing operational costs, such as extending a refuelling outage to shuffle high exposure blades. This paper examines the blade replacement strategies used by BWR utilities operating in US, Europe and Asia by assembling information related to: the utility's specific blade replacement strategy; the impact the newer blade designs and changes in core operating mode were having on those strategies; the mechanical and nuclear limits that determined those strategies; the methods employed to ensure that lifetime limits were not exceeded during operation; and blade designs used (current and replacement blades). (author)

  7. BWR control blade replacement strategies

    International Nuclear Information System (INIS)

    Kennard, M.W.; Harbottle, J.E.

    2000-01-01

    The reactivity control elements in a BWR, the control blades, perform three significant functions: provide shutdown margin during normal and accident operating conditions; provide overall core reactivity control; and provide axial power shaping control. As such, the blades are exposed to the core's neutron flux, resulting in irradiation of blade structural and absorber materials. Since the absorber depletes with time (if B 4 C is used, it also swells) and the structural components undergo various degradation mechanisms (e.g., embrittlement, corrosion), the blades have limits on their operational lifetimes. Consequently, BWR utilities have implemented strategies that aim to maximize blade lifetimes while balancing operational costs, such as extending a refuelling outage to shuffle high exposure blades. This paper examines the blade replacement strategies used by BWR utilities operating in US, Europe and Asia by assembling information related to: the utility's specific blade replacement strategy; the impact the newer blade designs and changes in core operating mode were having on those strategies; the mechanical and nuclear limits that determined those strategies; the methods employed to ensure that lifetime limits were not exceeded during operation; and blade designs used (current and replacement blades). (author)

  8. Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

    Directory of Open Access Journals (Sweden)

    Tubagus Ismail

    2012-09-01

    Full Text Available The purpose of this study was to examine the relationship between management control system (MCS and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AMOS Software 16 program is used as an additional instrument to resolve the problem in SEM modeling. The study found that interactive control system brought a positive and significant influence on Intended strategy; interactive control system brought a positive and significant influence on implemented strategy; interactive control system brought a positive and significant influence on emergent strategy. The limitation of this study is that our empirical model only used one way relationship between the process of strategy formation and interactive control system.

  9. Amoeba-related health risk in drinking water systems: could monitoring of amoebae be a complementary approach to current quality control strategies?

    Science.gov (United States)

    Codony, Francesc; Pérez, Leonardo Martín; Adrados, Bárbara; Agustí, Gemma; Fittipaldi, Mariana; Morató, Jordi

    2012-01-01

    Culture-based methods for fecal indicator microorganisms are the standard protocol to assess potential health risk from drinking water systems. However, these traditional fecal indicators are inappropriate surrogates for disinfection-resistant fecal pathogens and the indigenous pathogens that grow in drinking water systems. There is now a range of molecular-based methods, such as quantitative PCR, which allow detection of a variety of pathogens and alternative indicators. Hence, in addition to targeting total Escherichia coli (i.e., dead and alive) for the detection of fecal pollution, various amoebae may be suitable to indicate the potential presence of pathogenic amoeba-resisting microorganisms, such as Legionellae. Therefore, monitoring amoeba levels by quantitative PCR could be a useful tool for directly and indirectly evaluating health risk and could also be a complementary approach to current microbial quality control strategies for drinking water systems.

  10. Current Strategies in Cardiovascular Biomaterial Functionalization

    Directory of Open Access Journals (Sweden)

    Karla Lehle

    2010-01-01

    Full Text Available Prevention of the coagulation cascade and platelet activation is the foremost demand for biomaterials in contact with blood. In this review we describe the underlying mechanisms of these processes and offer the current state of antithrombotic strategies. We give an overview of methods to prevent protein and platelet adhesion, as well as techniques to immobilize biochemically active molecules on biomaterial surfaces. Finally, recent strategies in biofunctionalization by endothelial cell seeding as well as their possible clinical applications are discussed.

  11. Inventory control strategies

    International Nuclear Information System (INIS)

    Primrose, D.

    1998-01-01

    Finning International Inc. is in the business of selling, financing and servicing Caterpillar and complementary equipment. Its main markets are in western Canada, Britain and Chile. This paper discusses the parts inventory strategies system for Finning (Canada). The company's territory covers British Columbia, Alberta, the Yukon and the Northwest Territories. Finning's parts inventory consists of 80,000 component units valued at more than $150 M. Distribution centres are located in Langley, British Columbia and Edmonton, Alberta. To make inventory and orders easier to control, Finning has designed a computer-based system, with software written exclusively for Caterpillar dealers. The system makes use of a real time electronic interface with all Finning locations, plus all Caterpillar facilities and other dealers in North America. Details of the system are discussed, including territorial stocking procedures, addition to stock, exhaustion of stock, automatic/suggest order controls, surplus inventory management, and procedures for jointly managed inventory. 3 tabs., 1 fig

  12. Tax Strategy Control

    DEFF Research Database (Denmark)

    Rossing, Christian Plesner

    2013-01-01

    This paper examines how a functional tax strategy impacts the management control system (MCS) in a multinational enterprise (MNE) facing transfer pricing tax risks. Based on case study findings it is argued that the MCS in a multinational setting is contingent upon the MNE's response to its tax...... environment. Moreover, the paper extends existing contingency-based theory on MCS by illustrating the role of inter-organisational network collaboration across MNE transfer pricing tax experts. This collaboration, caused by a widely dispersed tax knowledge base, fuels the formal interactive control system...... and reduces tax uncertainty. The paper adopts an interdisciplinary approach for explaining findings, using contingency-based theory and network theory at the inter-organisational level....

  13. Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

    OpenAIRE

    Tubagus Ismail; Darjat Sudrajat

    2012-01-01

    The purpose of this study was to examine the relationship between management control system (MCS) and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM) as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AM...

  14. A Novel Sensorless Control Strategy for Brushless Direct Current Motor Based on the Estimation of Line Back Electro-Motive Force

    Directory of Open Access Journals (Sweden)

    Chengde Tong

    2017-09-01

    Full Text Available In this paper, a novel sensorless control strategy based on the estimation of line back electro-motive force (BEMF is proposed. According to the phase relationship between the ideal commutation points of the brushless direct current motor (BLDCM and the zero-crossing points (ZCPs of the line BEMF, the calculation formula of line BEMF is simplified properly and the commutation rule for different positions of the rotor is presented. The estimation error of line BEMF caused by the freewheeling current of silent phase is analyzed, and the solution is given. With the phase shift of the low-pass filter considered, a compensation method using “60°-α” and “120°-α” is studied in this paper to eliminate the error. Finally, the simulation and experimental results show that the rotor-position-detection error is reduced effectively and the motor driven by the accurate commutation signal can work well at low and high speed.

  15. Control strategy minimizing the converter-alternating current motor losses: application to electric traction; Strategies de commande minimisant les pertes d'un ensemble convertisseur - machine alternative: application a la traction electrique

    Energy Technology Data Exchange (ETDEWEB)

    Bastiani, Ph.

    2001-02-01

    Improving the efficiency of the converter-alternating current motor system is a major task in electric traction. Global energy optimisation implies a specific approach at system scale. To reach this goal, we have chosen an algebraic method using sub-system models. To start with, a synchronous machine Park model is developed to take account magnetic saturation and iron losses. Then, an averaged model of the voltage inverter is used in order to obtain a simplified model of the losses to be implemented in our optimisation method. This is how the global model is built including losses in the synchronous machine along with the losses of the power converter. Experimental results are there to validate our approach. This study proposes a method based on algebraic formulation of the general laws to control torque. Algorithms take into account magnetic circuits saturation and power losses in both the machine and its converter. Here again, experimental results validate the algorithm on several test benches. Achieved efficiency improvement is important compared to existing usual control strategies. The proposed method can be generalised to other machine-converter systems. As a matter of fact we have extended our study to the induction machine. As a complement ti this study we have looked at the effects natural limitations of voltages and currents in the torque-speed plane. Therefore algebraic formulation of the torque-speed plane and optimisation strategies are proposed including those constraints. (author)

  16. Preoperative transcranial direct current stimulation: Exploration of a novel strategy to enhance neuroplasticity before surgery to control postoperative pain. A randomized sham-controlled study.

    Directory of Open Access Journals (Sweden)

    Hugo Ribeiro

    Full Text Available An imbalance in the excitatory/inhibitory systems in the pain networks may explain the persistent chronic pain after hallux valgus surgery. Thus, to contra-regulate this dysfunction, the use of transcranial direct current stimulation (tDCS becomes attractive.We tested the hypothesis that two preoperative active(a-tDCS sessions compared with sham(s-tDCS could improve the postoperative pain [as indexed by Visual Analogue Scale (VAS at rest and during walking (primary outcomes]. To assess their effect on the change in the Numerical Pain Scale (NPS0-10 during Conditioned Pain Modulation (CPM-task, disability related to pain (DRP and analgesic consumption (secondary outcomes. Also, we assessed if the brain derived neurotrophic factor (BDNF in the cerebral spinal fluid (CSF after tDCS could predict the intervention's effect on the DRP.It is a prospective, double blind, sham-controlled, randomized single center, 40 women (18-70 years-old who had undergone hallux valgus surgery were randomized to receive two sessions (20 minutes each of anodal a-tDCS or s-tDCS on the primary motor cortex at night and in the morning before the surgery. To assess the DRP was used the Brazilian Profile of Chronic Pain: Screen (B-PCP:S.A-tDCS group showed lower scores on VAS at rest and during walking (P<0.001. At rest, the difference between groups was 2.13cm (95%CI = 1.59 to 2.68 while during walking was 1.67cm (95%CI = 1.05 to 2.28. A-tDCS, when compared to s-tDCS reduced analgesic doses in 73.25% (P<0.001, produced a greater reduction in B-PCP:S (mean difference of 9.41 points, 95%CI = 0.63 to 18.21 and higher function of descending pain modulatory system (DPMS during CPM-task.A-tDCS improves postoperative pain, the DRP and the function of DPMS. Also, the CSF BDNF after a-tDCS predicted the improvement in the DRP. In overall, these findings suggest that a-tDCS effects may be mediated by top-down regulatory mechanisms associated with the inhibitory cortical control

  17. A three-phase to three-phase series-resonant power converter with optimal input current waveforms, Part I: control strategy

    NARCIS (Netherlands)

    Huisman, H.

    1988-01-01

    A control strategy for multiphase-input multiphase-output AC to AC series-resonant (SR) power converters is presented. After reviewing some basics in SR power converters, a hierarchy of control mechanisms is presented, together with their respective theoretical backgrounds and practical limitations.

  18. Robust Two Degrees-of-freedom Single-current Control Strategy for LCL-type Grid-Connected DG System under Grid-Frequency Fluctuation and Grid-impedance Variation

    DEFF Research Database (Denmark)

    Zhou, Leming; Chen, Yandong; Luo, An

    2016-01-01

    -of-freedom single-current control (RTDOF-SCC) strategy is proposed, which mainly includes the synchronous reference frame quasi-proportional-integral (SRFQPI) control and robust grid-current-feedback active damping (RGCFAD) control. The proposed SRFQPI control can compensate the local-loads reactive power......, and regulate the instantaneous grid current without steady-state error regardless of the fundamental frequency fluctuation. Simultaneously, the proposed RGCFAD control effectively damps the LCL-resonance peak regardless of the grid-impedance variation, and further improves both transient and steady...

  19. Elevator Control Strategies

    OpenAIRE

    Ceder, Frederick; Nordin, Alexandra

    2013-01-01

    The purpose of this essay is to investigate if it is eective to switch strategies for elevators during one day in an oce building. This essay describes some of the strategies in use today, followed by a comparison and analysis of two of the strategies described. We have also implemented optimizations to one of these strategies. From our test results we can conclude that our optimized strategy worked and produced better results on average waiting time and total traveling time than the two stra...

  20. Zero-Voltage Switching PWM Strategy Based Capacitor Current-Balancing Control for Half-Bridge Three-Level DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Zhang, Qi

    2018-01-01

    The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation...

  1. Current NATO strategy and no first use

    International Nuclear Information System (INIS)

    Lubkemeier, E.

    1988-01-01

    This paper reports that spurred by the public controversy about the implementation of the NATO dual-track decision, the Western Alliance is currently in the third phase of its strategy debate. The first phase ended in 1967 with the official adoption of the doctrine of massive retaliation whose center-piece was NATO's threat to respond to a Soviet attack in Europe by an early and if need be massive use of nuclear weapons. Soon thereafter this concept was called in question in the US. The critics pointed out that at a time where its vulnerability to Soviet nuclear strikes was growing (the so-called Sputnik shock of 1957 played a special role in this context), it was too risky for the United States to stumble into a nuclear exchange with the USSR over any outbreak of an armed East-West confrontation in Europe. They therefore propounded that the over-reliance of the West's deterrence on nuclear arms be diminished in favor of a stronger conventional deterrent. With the advent of the Kennedy administration in January 1961, this stance became official American policy and was expounded to the European members of the Alliance by then Secretary of Defence McNamara. This second phase of the strategy debate was concluded in 1967 by promulgating the current strategy of Flexible Response

  2. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L......-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid...... passive (resistive) resonance damping solutions, due to their additional power losses, active damping (AD) techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF) AD has...

  3. Current issues and strategies for transmission planning

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, A.L. [Electranix, Winnipeg, MB (Canada); Rajapakse, A. [Manitoba Univ., Winnipeg, MB (Canada)

    2008-07-01

    Following the widespread deregulation of the electric power industry in the early 1990s, significant changes occurred in the regulatory and planning environments of the industry. Several regions of North America remain fully or partially regulated in the traditional sense including most Canadian provinces, except for Alberta and Ontario. Although the Mexican system has separate generation and transmission companies and current restructuring efforts are underway, all companies are state-owned, and private investment in energy is heavily constrained by the Mexican constitution. In these regulated regions, traditional generation and transmission expansion planning methods remain in use. This paper presented an overview of current trends in transmission planning strategies that have evolved in response to the restructuring of the power industry, and a conceptual framework of a procedure that would guide planners faced with the challenges of incorporating large scale wind generation in deregulated environments. The paper provided background information on the effect of deregulation on transmission planning. Planning strategies that were discussed included quantifying risk to help identify best alternatives; use of reference systems to estimate generator costs and reduce uncertainty; project based transmission expansion; transmission construction ahead of generation; and generation ahead of transmission. The impact of wind on transmission planning as well as future work addressing challenges posed by wind were also addressed. Research is continuing in this area to illustrate the concepts proposed through a detailed case study. 15 refs., 2 figs.

  4. Molecular imaging: current status and emerging strategies

    International Nuclear Information System (INIS)

    Pysz, M.A.; Gambhir, S.S.; Willmann, J.K.

    2010-01-01

    In vivo molecular imaging has a great potential to impact medicine by detecting diseases in early stages (screening), identifying extent of disease, selecting disease- and patient-specific treatment (personalized medicine), applying a directed or targeted therapy, and measuring molecular-specific effects of treatment. Current clinical molecular imaging approaches primarily use positron-emission tomography (PET) or single photon-emission computed tomography (SPECT)-based techniques. In ongoing preclinical research, novel molecular targets of different diseases are identified and, sophisticated and multifunctional contrast agents for imaging these molecular targets are developed along with new technologies and instrumentation for multi-modality molecular imaging. Contrast-enhanced molecular ultrasound (US) with molecularly-targeted contrast microbubbles is explored as a clinically translatable molecular imaging strategy for screening, diagnosing, and monitoring diseases at the molecular level. Optical imaging with fluorescent molecular probes and US imaging with molecularly-targeted microbubbles are attractive strategies as they provide real-time imaging, are relatively inexpensive, produce images with high spatial resolution, and do not involve exposure to ionizing irradiation. Raman spectroscopy/microscopy has emerged as a molecular optical imaging strategy for ultrasensitive detection of multiple biomolecules/biochemicals with both in vivo and ex vivo versatility. Photoacoustic imaging is a hybrid of optical and US techniques involving optically-excitable molecularly-targeted contrast agents and quantitative detection of resulting oscillatory contrast agent movement with US. Current preclinical findings and advances in instrumentation, such as endoscopes and microcatheters, suggest that these molecular imaging methods have numerous potential clinical applications and will be translated into clinical use in the near future.

  5. Strategies for humidity control

    Energy Technology Data Exchange (ETDEWEB)

    Baumgarth, S

    1987-01-01

    Humidity and temperature control in air-conditioning systems mostly involves coupled closed-loop control circuits. The author discusses their uncoupling and resulting consequences as well as energy-optimized control of recirculation air flaps or enthalpy recovering systems (h-x control) in detail. Special reference is made of the application of the DDC technology and its scope, limits and preconditions. In conclusions, the author presents pertinent measurement results. (orig.).

  6. National Drug Control Strategy, 2011

    Science.gov (United States)

    Office of National Drug Control Policy, 2011

    2011-01-01

    In May of 2010, President Obama released the Administration's inaugural "National Drug Control Strategy". Based on the premise that drug use and its consequences pose a threat not just to public safety, but also to public health, the 2010 "Strategy" represented the first comprehensive rebalancing of Federal drug control policy in the nearly 40…

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  8. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    Iman Lorzadeh

    2016-08-01

    Full Text Available Inductive-capacitive-inductive (LCL-type line filters are widely used in grid-connected voltage source inverters (VSIs, since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid passive (resistive resonance damping solutions, due to their additional power losses, active damping (AD techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF AD has attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking into account the effect of computation and pulse width modulation (PWM delays along with a detailed analysis on proper design and implementation.

  9. Current strategy for the imaging of neuroblastoma

    International Nuclear Information System (INIS)

    Brisse, H.; Neuenschwander, S.; Edeline, V.; Michon, J.; Zucker, J.M.; Couanet, D.

    2001-01-01

    Advances in the management of neuroblastoma lead radiologists and nuclear medicine specialists to optimize their procedures in order to propose a rational use of their techniques, adjusted to the various clinical presentations and to therapeutic management. The aim of this paper is to assess the imaging procedures for the diagnosis and follow-up of neuroblastoma in children according to current therapeutic European protocols. An imaging strategy at diagnosis is first proposed: optimal assessment of local extension of the primary tumour is made with MRI, or spiral-CT when MRI is not available, for all locations except for abdominal tumours for which CT remains the best imaging modality. Metastatic extension is assessed with mlBG scan and liver sonography. Indications for bone metastasis evaluation with either radiological or radionuclide techniques are detailed. Imaging follow-up during treatment for metastatic or unresectable tumours is described. A check-list of radiological main points to be evaluated before surgery is proposed for localized neuroblastoma. The imaging strategy for the diagnosis of 'occult' neuroblastoma is considered. Finally, we explain the management of neuroblastoma detected during the prenatal or neonatal period. (authors)

  10. Application of the Min-Projection and the Model Predictive Strategies for Current Control of Three-Phase Grid-Connected Converters: a Comparative Study

    Directory of Open Access Journals (Sweden)

    M. Oloumi

    2015-06-01

    Full Text Available This paper provides a detailed comparative study concerning the performance of min-projection strategy (MPS and model predictive control (MPC systems to control the three-phase grid connected converters. To do so, first, the converter is modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and its stability criterion is derived as a lower limit on the DC link voltage. Next, the fundamental equations of the MPS to control a VSC are obtained in the stationary reference frame. The mathematical analysis reveals that the MPS is independent of the load, grid, filter and converter parameters. This feature is a great advantage of MPS over the MPC approach. However, the latter is a well-known model-based control technique, has already developed for controlling the VSC in the stationary reference frame. To control the grid connected VSC, both MPS and MPC approaches are simulated in the PSCAD/EMTDC environment. Simulation results illustrate that the MPS is functioning well and is less sensitive to grid and filter inductances as well as the DC link voltage level. However, the MPC approach renders slightly a better performance in the steady state conditions.

  11. Magnetoelectric control of spin currents

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, J. E.; Vargas, J. M.; Avilés-Félix, L.; Butera, A. [Centro Atómico Bariloche, Instituto de Nanociencia y Nanotecnología (CNEA) and Conicet, 8400 Bariloche, Río Negro (Argentina)

    2016-06-13

    The ability to control the spin current injection has been explored on a hybrid magnetoelectric system consisting of a (011)-cut ferroelectric lead magnesium niobate-lead titanate (PMNT) single crystal, a ferromagnetic FePt alloy, and a metallic Pt. With this PMNT/FePt/Pt structure we have been able to control the magnetic field position or the microwave excitation frequency at which the spin pumping phenomenon between FePt and Pt occurs. We demonstrate that the magnetoelectric heterostructure operating in the L-T (longitudinal magnetized-transverse polarized) mode couples the PMNT crystal to the magnetostrictive FePt/Pt bilayer, displaying a strong magnetoelectric coefficient of ∼140 Oe cm kV{sup −1}. Our results show that this mechanism can be effectively exploited as a tunable spin current intensity emitter and open the possibility to create an oscillating or a bistable switch to effectively manipulate spin currents.

  12. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Science.gov (United States)

    Szmyd, Janusz S.; Komatsu, Yosuke; Brus, Grzegorz; Ghigliazza, Francesco; Kimijima, Shinji; Ściążko, Anna

    2014-09-01

    This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V) correlation. The current-based fuel control (CBFC) was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  13. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Directory of Open Access Journals (Sweden)

    Szmyd Janusz S.

    2014-09-01

    Full Text Available This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V correlation. The current-based fuel control (CBFC was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  14. National Drug Control Strategy. Update.

    Science.gov (United States)

    Office of National Drug Control Policy, Washington, DC.

    President Bush's new National Drug Control Strategy for 2003 focuses on three core priorities: stopping drug use before it starts; healing America's drug users; and disrupting the market. The 2003 strategy reports progress toward meeting the President's goals of reducing drug use by 10 percent over 2 years, and 25 percent over 5 years. With regard…

  15. Industrial strategy for nondestructive control

    International Nuclear Information System (INIS)

    Martin, P.; Michaut, J.P.

    1994-01-01

    For Electricite de France, the nondestructive control strategy passes by a responsibility of services, a competition between companies, a clarification of the market access and a dialogue with the companies

  16. Current challenges in tobacco control.

    Science.gov (United States)

    Slama, K

    2004-10-01

    Tobacco is the world's biggest preventable killer, but the circumstances of its history, the power and influence of its commerce and the nature of addiction make it a very difficult public health issue. Determinants of smoking are both individual and environmental. Genetics and environment influence to varying degrees all of the steps in a smoker's career. Persistence of use, degree of addiction to nicotine and difficulty in stopping are influenced by inherited traits and nicotine susceptibility, whereas the social environment and the individual's cognitions are the key factors in starting smoking and successfully stopping smoking. The tools available to tobacco control include influencing the social and cultural norms concerning tobacco; legislative and regulatory measures to protect the population and to limit tobacco industry marketing tactics, now encapsulated in the Framework Convention on Tobacco Control; and programmes to enhance the chance of not starting and successfully stopping. Strategies for tobacco control must work at both societal and individual levels, and directions are being taken that include genetic, pharmacological, behavioural, socio-cultural and international approaches.

  17. Current Evidence Supporting Obstetric Fistula Prevention Strategies ...

    African Journals Online (AJOL)

    Evidences from the articles were linked to prevention strategies retrieved from grey literature. The strategies were classified using an innovative target-focused method. Gaps in the literature show the need for fistula prevention research to aim at systematically measuring incidence and prevalence of the disease, identify the ...

  18. Disturbance observer based current controller for vector controlled IM drives

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Dal, Mehmet

    2008-01-01

    induction motor (IM) drives. The control design, based on synchronously rotating d-q frame model of the machine, has a simple structure that combines the proportional portion of a conventional PI control and output of the observer. The observer is predicted to estimate the disturbances caused by parameters...... coupling effects and increase robustness against parameters change without requiring any other compensation strategies. The experimental implementation results are provided to demonstrate validity and performance of the proposed control scheme.......In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...

  19. A randomised controlled trial evaluating IGF1 titration in contrast to current GH dosing strategies in children born small for gestational age

    DEFF Research Database (Denmark)

    Jensen, Rikke Beck; Thankamony, Ajay; O'Connell, Susan M

    2014-01-01

    BACKGROUND: Short children born small for gestational age (SGA) are treated with a GH dose based on body size, but treatment may lead to high levels of IGF1. The objective was to evaluate IGF1 titration of GH dose in contrast to current dosing strategies. METHODS: In the North European Small......-for-Gestational-Age Study (NESGAS), 92 short pre-pubertal children born SGA were randomised after 1 year of high-dose GH treatment (67 μg/kg per day) to three different regimens: high dose (67 μg/kg per day), low dose (35 μg/kg per day) or IGF1 titration. RESULTS: The average dose during the second year of the randomised...... trial did not differ between the IGF1 titration group (38 μg/kg per day, s.d. 0.019) and the low-dose group (35 μg/kg per day, s.d. 0.002; P=0.46), but there was a wide variation in the IGF1 titration group (range 10-80 μg/kg per day). The IGF1 titration group had significantly lower height gain (0...

  20. Current Immunotherapeutic Strategies to Enhance Oncolytic Virotherapy

    Directory of Open Access Journals (Sweden)

    Daniel E. Meyers

    2017-06-01

    Full Text Available Oncolytic viruses (OV represent a promising strategy to augment the spectrum of cancer therapeutics. For efficacy, they rely on two general mechanisms: tumor-specific infection/cell-killing, followed by subsequent activation of the host’s adaptive immune response. Numerous OV genera have been utilized in clinical trials, ultimately culminating in the 2015 Food and Drug Administration approval of a genetically engineered herpes virus, Talminogene laherparepvec (T-VEC. It is generally accepted that OV as monotherapy have only modest clinical efficacy. However, due to their ability to elicit specific antitumor immune responses, they are prime candidates to be paired with other immune-modulating strategies in order to optimize therapeutic efficacy. Synergistic strategies to enhance the efficacy of OV include augmenting the host antitumor response through the insertion of therapeutic transgenes such as GM-CSF, utilization of the prime-boost strategy, and combining OV with immune-modulatory drugs such as cyclophosphamide, sunitinib, and immune checkpoint inhibitors. This review provides an overview of these immune-based strategies to improve the clinical efficacy of oncolytic virotherapy.

  1. Current strategy for leprosy control in Brazil: time to pursue alternative preventive strategies? Estrategia actual para el control de la lepra en Brasil: ¿es hora de investigar otras estrategias de prevención?

    OpenAIRE

    Sérgio S. Cunha; Laura C. Rodrigues; Nádia Cristina Duppre

    2004-01-01

    La estrategia actual para el control de la lepra en Brasil se basa en dos actividades principales: la detección precoz de casos y el tratamiento de casos con farmacoterapia combinada. Además de dichas medidas, se realizan esfuerzos complementarios para identificar los contactos domésticos para el diagnóstico precoz y la vacunación con el bacilo de Calmette-Guérin (BCG). Sin embargo, la eficacia de estas acciones a la hora de reducir la incidencia de la lepra es aún discutible. Esto genera dud...

  2. Tissue Engineering: Current Strategies and Future Directions

    OpenAIRE

    Olson, Jennifer L.; Atala, Anthony; Yoo, James J.

    2011-01-01

    Novel therapies resulting from regenerative medicine and tissue engineering technology may offer new hope for patients with injuries, end-stage organ failure, or other clinical issues. Currently, patients with diseased and injured organs are often treated with transplanted organs. However, there is a shortage of donor organs that is worsening yearly as the population ages and as the number of new cases of organ failure increases. Scientists in the field of regenerative medicine and tissue eng...

  3. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Directory of Open Access Journals (Sweden)

    Vedantam Rajshekhar

    2016-01-01

    Full Text Available Neurocysticercosis (NCC is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues.

  4. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Science.gov (United States)

    Rajshekhar, Vedantam

    2016-01-01

    Neurocysticercosis (NCC) is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis) can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug) may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues. PMID:28139530

  5. Antibiotic resistance: current issues and future strategies

    Directory of Open Access Journals (Sweden)

    Giancarlo Scarafile

    2016-09-01

    Full Text Available The antibiotic resistance (antimicrobial resistance – AMR and the particular emergence of multi-resistant bacterial strains, is a problem of clinical relevance involving serious threats to public health worldwide. From early this decade, a lot of studies have demonstrated a significant increase in the rates of antibiotic resistance by bacterial pathogens responsible for nosocomial and community infections all over the world. The AMR leads to a reduced drug efficacy in the treatment options available and therefore, to an increase in mortality rates. The original causes of the phenomenon are: environmental factors which favor a mutation of the genetic bacterial inheritance, thereby inhibiting the active ingredient of the antibiotics; unsuitable administering of antibiotics in veterinary, incorrect taking both in hospitals and at home and, lately, lack of investments in the development of new drugs. The alarming epidemiological data prompted the World Health Organization (WHO in 2011 to coin the slogan "No action today, no cure tomorrow" in order to immediately implement a new strategy to improve the use of available drugs and to accelerate the introduction of new ones through a new phase of research involving private and public institutions. The European Union has stressed that the surveillance is considered an essential factor for an effective response to this problem but it has also highlighted that the results produced have been lower than expectations because of serious shortcomings such as lack of methodological standards, insufficient data sharing and no coordination among European countries. In Italy the situation is much more troubling; in fact, according to the Ministry of Health, 5000-7000 yearly deaths are deemed due to nosocomial infections, with an annual cost of more than 100 million €.These figures explain how the fight against infections is far from being won. The purpose of this review is to analyze the basic causes of the

  6. Strategies for reactive power control in wind farms with STATCOM

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Gonzalez, Francisco [Catalonia Institute for Energy Research (IREC), Barcelona (Spain); Martinez-Rojas, Marcela [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Barcelona (Spain). Dept. d' Enginyeria Electrica; Sumper, Andreas; Gomis-Bellmunt, Oriol [Catalonia Institute for Energy Research (IREC), Barcelona (Spain); Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Barcelona (Spain). Dept. d' Enginyeria Electrica

    2010-07-01

    This paper presents two strategies for reactive current control in wind farms with STATCOM under fault ride-through (FRT) situations. First, the technical requirements of the Spanish and German grid codes related to the reactive current under FRT situations are presented. Second, STATCOM and its control system are introduced. Third, the modeling done of the wind farm, the STATCOM, and the network are presented. Finally, control strategies for reactive current delivered by the park to the network under FRT situations are shown. The result of the implementation of each control strategy is shown by simulation. (orig.)

  7. Stability analysis of direct current control in current source rectifier

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

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

  8. Stereotactic body radiotherapy: current strategies and future development

    Science.gov (United States)

    2016-01-01

    Stereotactic body radiotherapy (SBRT) has emerged as the standard treatment for medically inoperable early-staged non-small cell lung cancer (NSCLC). The local control rate after SBRT is over 90%. Some forms of tumour motion management and image-guided radiation delivery techniques are the prerequisites for fulfilment of its goal to deliver a high radiation dose to the tumour target without overdosing surrounding normal tissues. In this review, the current strategies of tumour motion management will be discussed, followed by an overview of various image-guided radiotherapy (RT) systems and devices available for clinical practice. Besides medically inoperable stage I NSCLC, SBRT has also been widely adopted for treatment of oligometastasis involving the lungs. Its possible applications in various other cancer illnesses are under extensive exploration. The progress of SBRT is critically technology-dependent. With advancement of technology, the ideal of personalised, effective and yet safe SBRT is already on the horizon. PMID:27606082

  9. Variable current speed controller for eddy current motors

    Science.gov (United States)

    Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

    1982-03-12

    A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

  10. Biocorrosion control: Current strategies and promising alternatives ...

    African Journals Online (AJOL)

    Metal corrosion is an electrochemical reaction between the environment and a metal, in which microbes are thought to play a very important role. The rates at which various types of metals corrode are dependent upon environmental conditions as well as on the type of metals. The most well studied bacteria involved in ...

  11. Implementation strategy for the ITER plasma control system

    International Nuclear Information System (INIS)

    Winter, A.; Ambrosino, G.; Bauvir, B.; De Tommasi, G.; Humphreys, D.A.; Mattei, M.; Neto, A.; Raupp, G.; Snipes, J.A.; Stephen, A.V.; Treutterer, W.; Walker, M.L.; Zabeo, L.

    2015-01-01

    This paper gives an overview of the scope and context of the CODAC high-level real-time applications (Supervision and Plasma Control) and presents the strategy and current state of design of the tools to support the implementation. A real-time framework, which is currently under development with strong support of the worldwide fusion community will not only support the implementation of plasma control strategies with the extensive exception handling and forecasting functionality foreseen for ITER, but also integrated commissioning, orchestration and supervision as well as the real-time needs of ITER plant system developers. A second cornerstone in the implementation strategy is the development of a powerful simulation environment (Plasma Control System Simulation Platform – PCSSP) to design and verify control strategies, event handling and orchestration and automation. The development of PCSSP is currently under contract and this paper will also give an overview of its current state of development.

  12. Implementation strategy for the ITER plasma control system

    Energy Technology Data Exchange (ETDEWEB)

    Winter, A., E-mail: axel.winter@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Ambrosino, G. [CREATE/Università di Napoli Federico II, Dip. Ingegneria Elettrica e delle Tecnologie dell’Informazione (Italy); Bauvir, B. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); De Tommasi, G. [CREATE/Università di Napoli Federico II, Dip. Ingegneria Elettrica e delle Tecnologie dell’Informazione (Italy); Humphreys, D.A. [General Atomics, San Diego, CA (United States); Mattei, M. [CREATE/Seconda Università di Napoli, Dip. Ingegneria Industriale e dell’Informazione (Italy); Neto, A. [Fusion for Energy, Barcelona (Spain); Raupp, G. [Max Planck Institute for Plasma Physics, EURATOM Association, Garching (Germany); Snipes, J.A. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Stephen, A.V. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon (United Kingdom); Treutterer, W. [Max Planck Institute for Plasma Physics, EURATOM Association, Garching (Germany); Walker, M.L. [General Atomics, San Diego, CA (United States); Zabeo, L. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France)

    2015-10-15

    This paper gives an overview of the scope and context of the CODAC high-level real-time applications (Supervision and Plasma Control) and presents the strategy and current state of design of the tools to support the implementation. A real-time framework, which is currently under development with strong support of the worldwide fusion community will not only support the implementation of plasma control strategies with the extensive exception handling and forecasting functionality foreseen for ITER, but also integrated commissioning, orchestration and supervision as well as the real-time needs of ITER plant system developers. A second cornerstone in the implementation strategy is the development of a powerful simulation environment (Plasma Control System Simulation Platform – PCSSP) to design and verify control strategies, event handling and orchestration and automation. The development of PCSSP is currently under contract and this paper will also give an overview of its current state of development.

  13. A Synthesis of Language Learning Strategies: Current Issues, Problems and Claims Made in Learner Strategy Research

    Science.gov (United States)

    Barjesteh, Hamed; Mukundan, Jayakaran; Vaseghi, Reza

    2014-01-01

    The current paper presented theoretical assumptions behind language learning strategies (LLS) and an overview of methods used to identify learners' strategies, first, and then summarized what have been reported from large number of descriptive studies of strategies by language learners. Moreover, the paper tried to present the variety of…

  14. X-ray tube current control

    International Nuclear Information System (INIS)

    Dupuis, W.A.; Resnick, T.A.

    1982-01-01

    A closed loop feedback system for controlling the current output of an x-ray tube. The system has circuitry for improving the transient response and stability of the x-ray tube current over a substantial nonlinear portion of the tube current production characteristic. The system includes a reference generator for applying adjustable step function reference signals representing desired tube currents. The system also includes means for instantaneous sensing of actual tube current. An error detector compares the value of actual and reference tube current and produces an error signal as a function of their difference. The system feedback loop includes amplification circuitry for controlling x-ray tube filament dc voltage to regulate tube current as a function of the error signal value. The system also includes compensation circuitry, between the reference generator and the amplification circuitry, to vary the loop gain of the feedback control system as a function of the reference magnitude

  15. Occupant satisfaction with two blind control strategies

    DEFF Research Database (Denmark)

    Karlsen, Line Røseth; Heiselberg, Per Kvols; Bryn, Ida

    2015-01-01

    Highlights •Occupant satisfaction with two blind control strategies has been studied. •Control based on cut-off position of slats was more popular than closed slats. •Results from the study are helpful in development of control strategies for blinds. •The results give indications of how blinds...

  16. Proportional-Integral-Resonant AC Current Controller

    Directory of Open Access Journals (Sweden)

    STOJIC, D.

    2017-02-01

    Full Text Available In this paper an improved stationary-frame AC current controller based on the proportional-integral-resonant control action (PIR is proposed. Namely, the novel two-parameter PIR controller is applied in the stationary-frame AC current control, accompanied by the corresponding parameter-tuning procedure. In this way, the proportional-resonant (PR controller, common in the stationary-frame AC current control, is extended by the integral (I action in order to enable the AC current DC component tracking, and, also, to enable the DC disturbance compensation, caused by the voltage source inverter (VSI nonidealities and by nonlinear loads. The proposed controller parameter-tuning procedure is based on the three-phase back-EMF-type load, which corresponds to a wide range of AC power converter applications, such as AC motor drives, uninterruptible power supplies, and active filters. While the PIR controllers commonly have three parameters, the novel controller has two. Also, the provided parameter-tuning procedure needs only one parameter to be tuned in relation to the load and power converter model parameters, since the second controller parameter is directly derived from the required controller bandwidth value. The dynamic performance of the proposed controller is verified by means of simulation and experimental runs.

  17. Therapeutic strategies to improve control of hypertension.

    Science.gov (United States)

    Armario, Pedro; Waeber, Bernard

    2013-03-01

    Blood pressure is poorly controlled in most European countries and the control rate is even lower in high-risk patients such as patients with chronic kidney disease, diabetic patients or previous coronary heart disease. Several factors have been associated with poor control, some of which involve the characteristic of the patients themselves, such as socioeconomic factors, or unsuitable life-styles, other factors related to hypertension or to associated comorbidity, but there are also factors directly associated with antihypertensive therapy, mainly involving adherence problems, therapeutic inertia and therapeutic strategies unsuited to difficult-to-control hypertensive patients. It is common knowledge that only 30% of hypertensive patients can be controlled using monotherapy; all the rest require a combination of two or more antihypertensive drugs, and this can be a barrier to good adherence and log-term persistence in patients who also often need to use other drugs, such as antidiabetic agents, statins or antiplatelet agents. The fixed combinations of three antihypertensive agents currently available can facilitate long-term control of these patients in clinical practice. If well tolerated, a long-term therapeutic regimen that includes a diuretic, an ACE inhibitor or an angiotensin receptor blocker, and a calcium channel blocker is the recommended optimal triple therapy.

  18. Management strategies of enterovirus D68 outbreaks: current perspectives

    Directory of Open Access Journals (Sweden)

    Milhano N

    2018-03-01

    Full Text Available Natacha Milhano, Kaja Sverdrup Borge, Karoline Bragstad, Susanne G Dudman Domain for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway Abstract: Following its discovery in California in 1962, enterovirus D68 (EV-D68 was reported only sporadically around the world. In August 2014, a marked increase of EV-D68 cases in young children with severe respiratory infections was reported in the USA and Canada and later in Europe and Asia. Some of these cases were also found to be associated with acute flaccid paralysis, which exacerbated public health concern, and has since triggered international efforts to strengthen both EV-D68 and acute flaccid paralysis surveillance systems. This review summarizes the current knowledge on EV-D68, offering an overview of EV-D68 epidemiology, clinical presentations, diagnostic methodologies, and treatment strategies, as well as surveillance and outbreak management. Keywords: enterovirus D68, AFP, diagnostics, treatment, surveillance, outbreak 

  19. Control Strategy Tool (CoST)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The EPA Control Strategy Tool (CoST) is a software tool for projecting potential future control scenarios, their effects on emissions and estimated costs. This tool...

  20. Current collective engagement stakeholder strategies for South African labour relations

    Directory of Open Access Journals (Sweden)

    Popi C. Madlala

    2018-05-01

    Full Text Available Orientation: Collective engagement stakeholder strategies are significant for the creation of harmony in the workplace. It is a known fact that the South African (SA labour environment has been dominated by industrial action before and after the 1994 democratic transition. To be precise, the statistics reveals that industrial action has increased and become more destructive post-1994. Purpose: The purpose of this article was to present the current collective engagement stakeholder strategies for South African labour relations. Motivation for the study: The SA mining sector has seen more violent strikes, with a higher number of deaths, injuries, criminal activities, arrests, dismissals and job losses in recent years. This article captures the current mining stakeholder strategies shaping the existing labour relations environment. Research approach, design and method: This is a theoretical article highlighting the recent literature on collective engagement in the mining sector in South Africa. Main findings: This article presents the current labour relations incidents, reflecting the need for more effective collective engagement and stakeholder management strategies. Practical and managerial implications: The current labour relations context has prompted key stakeholders at the National Economic Development and Labour Council (NEDLAC to look specifically at promoting employment, labour market stability, the right to strike, minimising violence through collective bargaining and highlighting the role of the state, reducing vulnerability through social protection and increasing the minimum wage. Contribution or value add: This article adds theoretically to the existing body of knowledge regarding collective engagement and stakeholder strategies in the SA mining sector.

  1. Optimal control of anthracnose using mixed strategies.

    Science.gov (United States)

    Fotsa Mbogne, David Jaures; Thron, Christopher

    2015-11-01

    In this paper we propose and study a spatial diffusion model for the control of anthracnose disease in a bounded domain. The model is a generalization of the one previously developed in [15]. We use the model to simulate two different types of control strategies against anthracnose disease. Strategies that employ chemical fungicides are modeled using a continuous control function; while strategies that rely on cultivational practices (such as pruning and removal of mummified fruits) are modeled with a control function which is discrete in time (though not in space). For comparative purposes, we perform our analyses for a spatially-averaged model as well as the space-dependent diffusion model. Under weak smoothness conditions on parameters we demonstrate the well-posedness of both models by verifying existence and uniqueness of the solution for the growth inhibition rate for given initial conditions. We also show that the set [0, 1] is positively invariant. We first study control by impulsive strategies, then analyze the simultaneous use of mixed continuous and pulse strategies. In each case we specify a cost functional to be minimized, and we demonstrate the existence of optimal control strategies. In the case of pulse-only strategies, we provide explicit algorithms for finding the optimal control strategies for both the spatially-averaged model and the space-dependent model. We verify the algorithms for both models via simulation, and discuss properties of the optimal solutions. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Control Strategy for Echinococcus multilocularis

    OpenAIRE

    Hegglin, Daniel; Deplazes, Peter

    2008-01-01

    Echinococcus multilocularis, the causative agent of zoonotic alveolar echinococcosis, can be controlled effectively by the experimental delivery of anthelminthic baits for urban foxes. Monthly baiting over a 45-month period was effective for long-lasting control. Trimonthly baiting intervals were far less effective and did not prevent parasite recovery.

  3. Strategies for Industrial Multivariable Control

    DEFF Research Database (Denmark)

    Hangstrup, M.

    dynamics and gains strongly depend upon one or more physical parameters characterizing the operating point. This class covers many industrial systems such as airplanes, ships, robots and process control systems. Power plant boilers are representatives for process control systems in general. The dynamics...

  4. Soil Contamination and Remediation Strategies. Current research and future challenge

    Science.gov (United States)

    Petruzzelli, G.

    2012-04-01

    eliminating the source of pollution, but also on blocking the pathways from contaminants to receptors or reducing the exposure to contaminants,. Future challenge integration of sustainability into remediation decision-making. Soil is not a waste! There is a growing interest in the clean up approaches that maintain soil quality after remediation treatments. This issue is of great importance in the U.S.A. where the EPA from 2009 is promoting innovative clean-up strategies (Green Remediation). Green remediation is defined as the practice of considering all environmental effects of remedy and incorporating options to maximize environmental benefit of cleanup actions . These remediation strategies restore contaminated sites to productive use with a great attention to the global environmental quality, including the preservation of soil functionality according to the following principles: use minimally invasive technologies; use passive energy technologies such as bioremediation and phytoremediation as primary remedies or finishing steps where possible and effective; minimize soil and habitat disturbance; minimize bioavailability of contaminants trough adequate contaminant source and plume control If we move from the current definition of remedial targets based on total concentrations, technologies with low impact on the environment can be utilized reducing the wrong choice to disposal soil in landfill destroying quickly a not renewable essential resource.

  5. Part 2 -- current program integrating strategies and lubrication technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.

    1996-12-01

    This paper is the second of two that describe the Predictive Maintenance Program for rotating machinery at the Palo Verde Nuclear Generating Station. The Predictive Maintenance program has been enhanced through organizational changes and improved interdisciplinary usage of technology. This paper will discuss current program strategies that have improved the interaction between the Vibration and Lube Oil programs. The {open_quotes}Lube Oil{close_quotes} view of the combined program along with case studies will then be presented.

  6. Part 2 -- current program integrating strategies and lubrication technology

    International Nuclear Information System (INIS)

    Johnson, B.

    1996-01-01

    This paper is the second of two that describe the Predictive Maintenance Program for rotating machinery at the Palo Verde Nuclear Generating Station. The Predictive Maintenance program has been enhanced through organizational changes and improved interdisciplinary usage of technology. This paper will discuss current program strategies that have improved the interaction between the Vibration and Lube Oil programs. The open-quotes Lube Oilclose quotes view of the combined program along with case studies will then be presented

  7. Current and emerging somatic treatment strategies in psychotic major depression.

    Science.gov (United States)

    Dannon, Pinhas N; Lowengrub, Katherine; Gonopolski, Yehudit; Kotler, Moshe

    2006-01-01

    Psychotic major depressive disorder (MDD) is a mood disorder characterized by severe affective and neurovegetative symptoms together with the presence of delusions and/or hallucinations. It is a common disorder seen in a quarter of consecutively admitted depressed patients and is often associated with severe symptomatology, increased suicide risk, poor acute response to antidepressants and poor acute and long-term treatment outcome. It is possible that poor response in psychotic depression is caused by the fact that we have yet to identify the most efficacious treatment protocol for psychotic MDD. Multiple studies have shown that modifications in the treatment paradigm may increase treatment efficacy in psychotic MDD. It has been generally accepted that, during the acute treatment phase, antidepressant-antipsychotic drug combination therapy is more effective than either treatment alone, although this strategy has recently been challenged. The question of the optimal duration of pharmacotherapy in order to prevent relapse and improve long-term (i.e., 5-year) outcome is a focus of current investigation. This article will review currently recommended treatment strategies for the acute, continuation and maintenance phases of therapy. In particular, it will address the role of newer-generation antidepressants, the role of second-generation antipsychotics, the use of mood stabilizers and indications for electroconvulsive therapy. Other possible treatment strategies such as transcranial magnetic stimulation, vagus nerve stimulation, deep-brain stimulation and glucocorticoid receptor antagonists will be discussed. Current recommendations for the prevention of relapse and improvement of long-term outcome will be reviewed.

  8. Designing a sustainable strategy for malaria control?

    Directory of Open Access Journals (Sweden)

    Mharakurwa Sungano

    2011-08-01

    Full Text Available Abstract Malaria in the 21st century is showing signs of declining over much of its distribution, including several countries in Africa where previously this was not thought to be feasible. Yet for the most part the strategies to attack the infection are similar to those of the 1950s. Three major Journals have recently drawn attention to the situation, stressing the importance of research, describing the successes and defining semantics related to control. But there is a need to stress the importance of local sustainability, and consider somewhat urgently how individual endemic countries can plan and implement the programmes that are currently financed, for the most part, by donor institutions. On an immediate basis research should be more focused on a data driven approach to control. This will entail new thinking on the role of local infrastructure and in training of local scientists in local universities in epidemiology and field malariology so that expanded control programmes can become operational. Donor agencies should encourage and facilitate development of career opportunities for such personnel so that local expertise is available to contribute appropriately.

  9. Safe current injection strategies for a STATCOM under asymmetrical grid faults

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Medeiros, Gustavo; Luna, Alvaro

    2010-01-01

    This paper explores different strategies to set the reference current of a STATCOM under unbalanced grid voltage conditions and determines the maximum deliverable reactive power in each case to guarantee the injected current is permanently within the STATCOM secure operation limits. The paper...... presents a comprehensive derivation of the proposed STATCOM control strategies to set the reactive current reference under unbalanced grid faults, together with an extensive evaluation using simulation and experimental results from a low-scale laboratory setup in order to verify and validate the dynamic...

  10. Control strategies for bovine dermatophilosis with particular ...

    African Journals Online (AJOL)

    The various control strategies for Dermatophilosis are discussed in this paper. Recommendations for control of Dermatophilosis in Nigeria on short term include ecto-parasite control by regular use of insecticide/acaricide in dips with added 0.03% copper sulphate or 1% solution of alum (potassium aluminium sulphate) ...

  11. Accreditation: a cultural control strategy.

    Science.gov (United States)

    Paccioni, André; Sicotte, Claude; Champagne, François

    2008-01-01

    The purpose of this paper is to describe and understand the effects of the accreditation process on organizational control and quality management practices in two Quebec primary-care health organizations. A multiple-case longitudinal study was conducted taking a mixed qualitative/quantitative approach. An analytical model was developed of the effects of the accreditation process on the type of organizational control exercised and the quality management practices implemented. The data were collected through group interviews, semi-directed interviews of key informers, non-participant observations, a review of the literature, and structured questionnaires distributed to all the employees working in both institutions. The accreditation process has fostered the implementation of consultation mechanisms in self-assessment teams. Improving assessments of client satisfaction was identified as a prime objective but, in terms of the values promoted in organizations, accreditation has little effect on the perceptions of employees not directly involved in the process. As long as not all staff members have integrated the basis for accreditation and its outcomes, the accreditation process appears to remain an external, bureaucratic control instrument. This study provides a theoretical model for understanding organizational changes brought about by accreditation of primary services. Through self-assessment of professional values and standards, accreditation may foster better quality management practices.

  12. CMS Data Analysis: Current Status and Future Strategy

    CERN Document Server

    Innocente, V

    2003-01-01

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

  13. Some thoughts on separation control strategies

    Indian Academy of Sciences (India)

    Flow separation generally leads to increased energy losses, instability and so ... Separation control strategy often refers to a clever (or intelligent) fluid ... bubble will have a certain influence, directly or indirectly, on the development of the shear.

  14. [Aedes aegypti control strategies: a review].

    Science.gov (United States)

    Zara, Ana Laura de Sene Amâncio; Santos, Sandra Maria Dos; Fernandes-Oliveira, Ellen Synthia; Carvalho, Roberta Gomes; Coelho, Giovanini Evelim

    2016-01-01

    to describe the main strategies to control Aedes aegypti, with emphasis on promising technological innovations for use in Brazil. this study is a non-systematic review of the literature. several technologies have been developed as alternatives in the control of Ae. aegypti, using different mechanisms of action, such as selective monitoring of the infestation, social interventions, dispersing insecticides, new biological control agents and molecular techniques for population control of mosquitoes, also considering the combination between them. Evolving technologies require evaluation of the effectiveness, feasibility and costs of implementation strategies as complementary to the actions already recommended by the National Program for Dengue Control. the integration of different compatible and effective vector control strategies, considering the available technologies and regional characteristics, appears to be a viable method to try to reduce the infestation of mosquitoes and the incidence of arbovirus transmitted by them.

  15. Strategies for the photo-control of endogenous protein activity.

    Science.gov (United States)

    Brechun, Katherine E; Arndt, Katja M; Woolley, G Andrew

    2017-08-01

    Photo-controlled or 'optogenetic' effectors interfacing with endogenous protein machinery allow the roles of endogenous proteins to be probed. There are two main approaches being used to develop optogenetic effectors: (i) caging strategies using photo-controlled conformational changes, and (ii) protein relocalization strategies using photo-controlled protein-protein interactions. Numerous specific examples of these approaches have been reported and efforts to develop general methods for photo-control of endogenous proteins are a current focus. The development of improved screening and selection methods for photo-switchable proteins would advance the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. HTGR Resilient Control System Strategy

    International Nuclear Information System (INIS)

    Stevens, Lynne M.

    2010-01-01

    A preeminent objective for corporate and government organizations is the protection of major investments, which is attained by achieving state awareness, a comprehensive understanding of security and safety, for critical infrastructures. Given the dependence of critical infrastructure on control systems for automation, the integrity of these systems and their ability to provide owner/operators a high degree of state awareness is essential in attaining a high degree of investment protection and public acceptance. Operators as well as government are therefore burdened to ensure they have a timely understanding of the status of their plant or all plants, respectively, to ensure efficient operations and investment and public protection. 'This characterization is a significant objective that must consider many aspects of instrumentation, control, and intelligent systems in order to achieve the required result. These aspects include sensory, communication, analysis, decision, and human system interfaces necessary to achieve fusion of data and presentation of results that will provide an understanding of what issues are important and why.

  17. HTGR Resilient Control System Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lynne M. Stevens

    2010-09-01

    A preeminent objective for corporate and government organizations is the protection of major investments, which is attained by achieving state awareness, a comprehensive understanding of security and safety, for critical infrastructures. Given the dependence of critical infrastructure on control systems for automation, the integrity of these systems and their ability to provide owner/operators a high degree of state awareness is essential in attaining a high degree of investment protection and public acceptance. Operators as well as government are therefore burdened to ensure they have a timely understanding of the status of their plant or all plants, respectively, to ensure efficient operations and investment and public protection. “This characterization is a significant objective that must consider many aspects of instrumentation, control, and intelligent systems in order to achieve the required result. These aspects include sensory, communication, analysis, decision, and human system interfaces necessary to achieve fusion of data and presentation of results that will provide an understanding of what issues are important and why.

  18. Novel deadbeat power control strategy for grid connected systems

    Directory of Open Access Journals (Sweden)

    Yousry Atia

    2015-09-01

    Full Text Available This paper introduces a novel approach for power control of three phase voltage source inverter (VSI in grid connected distribution generation system. In this approach, the control of active and reactive power is based on deadbeat control strategy. First, the difference between the reference and actual currents are introduced in different approach. Then current to power substitutions are carried out to obtain direct relationship between the required inverter voltage and instantaneous power errors. There is no need for coordinate transformation or PLL, where the required inverter voltage vector calculations carried out in α–β stationary reference frame. The proposed technique introduces two cross coupling components in the control function. Including these two components, the controller can achieve nearly zero steady-state tracking error of the controlled variables. To obtain fixed switching frequency operations, space vector modulation (SVM is used to synthesize the required inverter voltage vector and to generate the switching pulses for the VSI. The proposed strategy has the simplicity of the direct power control (DPC technique and doesn’t require any current control loops. The proposed strategy is experimentally implemented using fixed-point microcontroller. Simulation and experimental results are presented to confirm the superiority of the proposed strategy.

  19. Current control of light by nonreciprocal magnetoplasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yongkang, E-mail: yongkang.gong@southwales.ac.uk; Li, Kang; Carver, Sara; Martinez, Juan Jose; Huang, Jungang; Copner, Nigel [Wireless and Optoelectronics Research and Innovation Centre (WORIC), Faculty of Computing, Engineering and Science, University of South Wales, Cardiff CF37 1DL (United Kingdom); Thueux, Yoann; Avlonitis, Nick [Airbus Group Innovations, Quadrant House, Celtic Springs, Coedkernew, NP10 8FZ Newport (United Kingdom)

    2015-05-11

    The ability to actively control light has long been a major scientific and technological goal. We proposed a scheme that allows for active control of light by utilizing the nonreciprocal magnetoplasmonic effect. As a proof of concept, we applied current signal through an ultrathin metallic film in a magneto-plasmonic multilayer and found that dynamic photonic nonreciprocity appears in magnetic-optical material layer due to the magnetic field being induced from current signal and modulates surface plasmon polaritons trapped in the metal surface and the light reflected. The proposed concept provides a possible way for the active control of light and could find potential applications such as ultrafast optoelectronic signal processing for plasmonic nanocircuit technology and ultrafast/large-aperture free-space electro-optic modulation platform for wireless laser communication technology.

  20. Current status of RCA projects and strategies for future implementation

    International Nuclear Information System (INIS)

    Kim, Kyoung Pyo; Lee, Jeong Kong

    1998-12-01

    This report is intended to provide basic overall information about ways to promote technical cooperation within the framework of RCA to accelerate and coordinate cooperative activities in nuclear science and technology in Asia and the Pacific region through a thorough review on the current status and through suggesting future implementation strategies. The contents of this report include an overall introduction of RCA, guidelines and operating rules for RCA programmes, current status and future plans for RCA projects as well as the RCA vision for the next 25 years. By reviewing the current status and future implementation strategies for RCA projects, it will help to set up a national nuclear policy aimed at seeking maximum benefits from participation in RCA projects and to implement programmes for nuclear cooperation with Asian-Pacific countries. It is expected that as a lead country for the energy sector, which is one of five thematic areas for the year 1999 - 2000 cycle programmes, Korea will continue to make significant contributions towards the implementation of RCA programmes in the future. With this report, we plan to keep up with future developments as well as implement an effective cooperation with the countries in the region so that the opinion of Korea, one of the nuclear advanced countries in the region, can be fully reflected in the establishment of future plans for RCA programmes. (author). 3 refs., 5 tabs., 1 fig

  1. Valuable metals - recovery processes, current trends, and recycling strategies

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Peter; Lorenz, Tom; Martin, Gunther; Brett, Beate; Bertau, Martin [Institut fuer Technische Chemie, TU Bergakademie Freiberg, Leipziger Strasse 29, 09599, Freiberg (Germany)

    2017-03-01

    This Review provides an overview of valuable metals, the supply of which has been classified as critical for Europe. Starting with a description of the current state of the art, novel approaches for their recovery from primary resources are presented as well as recycling processes. The focus lies on developments since 2005. Chemistry strategies which are used in metal recovery are summarized on the basis of the individual types of deposit and mineral. In addition, the economic importance as well as utilization of the metals is outlined. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Control strategies for demand controlled ventilation in dwellings

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Drivsholm, Christian

    2011-01-01

    and efficient fans is becoming the standard solution. The building regulation requirement for air change in dwellings is often a constant value that has been chosen to avoid moisture related problems in the indoor environment. This required air change is sometimes sufficient, sometimes too low and sometimes too....... In the studied house two control strategies were tested. A simple strategy where all sensors and controls were located in the air handling unit and only the speed of the fans can be controlled, and a complex strategy where sensors were placed in each room and where individual control of air flow in each room...

  3. 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...

  4. Brushless DC motor speed control strategy of simulation research

    Directory of Open Access Journals (Sweden)

    Xiang Wen

    2017-01-01

    Full Text Available In view of the brushless DC motor speed regulation problem, an ideal control strategy is designed. Through the model and analysis of Brushless DC motor, the mathematical model of the brushless DC motor is obtained. By comparing three control strategies of PID control strategy, fuzzy control strategy and fuzzy PID control strategy, PID controller, fuzzy controller and fuzzy PID controller are designed respectively for simulation test. The simulation results show that the fuzzy PID controller has good control effect.

  5. Wind farm models and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.; Donovan, M.H.

    2005-08-01

    This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulation models are described, including wind turbine models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described. The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC connected active stall turbines. Finally, some simulation examples and conclusions are presented. (au)

  6. Improved Droop Control Strategy for Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Abusara, Mohammad; Sharkh, Suleiman; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for grid-connected inverters within microgrids is presented in this paper. The strategy is based on the classical P-ω and Q-V droop method. The improvement in the proposed control strategy is twofold: Firstly, the transient response of the droop controller is improved...... by replacing the traditional method of measuring average power, which is based on using a first order low pass filter, by a real time integration filter. This is shown to reduce the imported transient energy when connecting to the grid. Secondly, the steady state output current quality is improved by utilising...... a virtual inductance, which is shown to reject grid voltage harmonics disturbance and thus improve the output current THD. A small signal model of the inverter based on the transfer function approach is developed to analyse is stability and determine droop gains. Simulation and experimental results...

  7. Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Jose Roberto Boffino de Almeida

    1997-07-01

    The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

  8. Can rewiring strategy control the epidemic spreading?

    Science.gov (United States)

    Dong, Chao; Yin, Qiuju; Liu, Wenyang; Yan, Zhijun; Shi, Tianyu

    2015-11-01

    Relation existed in the social contact network can affect individuals' behaviors greatly. Considering the diversity of relation intimacy among network nodes, an epidemic propagation model is proposed by incorporating the link-breaking threshold, which is normally neglected in the rewiring strategy. The impact of rewiring strategy on the epidemic spreading in the weighted adaptive network is explored. The results show that the rewiring strategy cannot always control the epidemic prevalence, especially when the link-breaking threshold is low. Meanwhile, as well as strong links, weak links also play a significant role on epidemic spreading.

  9. Low Activity Waste Feed Process Control Strategy

    International Nuclear Information System (INIS)

    STAEHR, T.W.

    2000-01-01

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system

  10. Managing Work and Family: Do Control Strategies Help?

    Science.gov (United States)

    Versey, H. Shellae

    2015-01-01

    How can we effectively manage competing obligations from work and family without becoming overwhelmed? This question inspires the current study by examining control strategies that may facilitate better work-life balance, with a specific focus on the role of lowered aspirations and positive reappraisals, attitudes that underlie adaptive coping…

  11. Between architecture and model: Strategies for cognitive control

    NARCIS (Netherlands)

    Taatgen, Niels

    One major limitation of current cognitive architectures is that models are typically constructed in an “empty” architecture, and that the knowledge specifications (typically production rules) are specific to the particular task. This means that general cognitive control strategies have to be

  12. Keeping Current. Using BDA Strategies in the Library Media Center

    Science.gov (United States)

    Keller, Cynthia A.

    2005-01-01

    This article discusses BDA strategies--reading strategies that "good readers" use before, during, and after reading. These strategies are in conjunction with free reading as well as direct reading instruction by reading specialists and/or teachers. An explanation of "Before Reading Strategies," "During Reading Strategies," and "After Reading…

  13. Real-time control for long ohmic alternate current discharges

    International Nuclear Information System (INIS)

    Carvalho, Ivo S.; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.

    2014-01-01

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks

  14. Real-time control for long ohmic alternate current discharges

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.

    2014-05-15

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks.

  15. Osteoarthritis: detection, pathophysiology, and current/future treatment strategies.

    Science.gov (United States)

    Sovani, Sujata; Grogan, Shawn P

    2013-01-01

    Osteoarthritis (OA) is a disease of the joint, and age is the major risk factor for its development. Clinical manifestation of OA includes joint pain, stiffness, and loss of mobility. Currently, no pharmacological treatments are available to treat this specific joint disease; only symptom-modifying drugs are available. Improvement in imaging technology, identification of biomarkers, and increased understanding of the molecular basis of OA will aid in detecting the early stages of disease. Yet the development of interventional strategies remains elusive and will be critical for effective prevention of OA-associated joint destruction. The potential of cell-based therapies may be applicable in improving joint function in mild to more advanced cases of OA. Ongoing studies to understand the basis of this disease will eventually lead to prevention and treatment strategies and will also be a key in reducing the social and economic burden of this disease. Nurses are advised to provide an integrative approach of disease assessment and management in OA patients' care with a focus on education and implementation. Knowledge and understanding of OA and how this affects the individual patient form the basis for such an integrative approach to all-round patient care and disease management.

  16. Reimbursed Price of Orphan Drugs: Current Strategies and Potential Improvements.

    Science.gov (United States)

    Mincarone, Pierpaolo; Leo, Carlo Giacomo; Sabina, Saverio; Sarriá-Santamera, Antonio; Taruscio, Domenica; Serrano-Aguilar, Pedro Guillermo; Kanavos, Panos

    2017-01-01

    The pricing and reimbursement policies for pharmaceuticals are relevant to balance timely and equitable access for all patients, financial sustainability, and reward for valuable innovation. The proliferation of high-cost specialty medicines is particularly true in rare diseases (RDs) where the pricing mechanism is characterised by a lack of transparency. This work provides an overall picture of current strategies for the definition of the reimbursed prices of orphan drugs (ODs) and highlights some potential improvements. Current strategies and suggestions are presented along 4 dimensions: (1) comprehensive value assessment, (2) early dialogs among relevant stakeholders, (3) innovative reimbursement approaches, and (4) societal participation in producing ODs. Comprehensive value assessment could be achieved by clarifying the approach of distributive justice to adopt, ensuring a representative participation of stakeholders, and with a broad consideration of value-bearing factors. With respect to early dialogs, cross-border cooperation can be determinant to companies and agencies. The cost-benefit ratio of early dialogs needs to be demonstrated and the "regulatory capture" effect should be monitored. Innovative reimbursement approaches were developed to balance the need for evidence-based decisions with the timely access to innovative drugs. The societal participation in producing ODs needs to be recognised in a collaborating framework where adaptive agreements can be developed with mutual satisfaction. Such agreements could also impact on coverage and reimbursement decisions as additional elements for the determination of a comprehensive societal value of ODs. Further research is needed to investigate the highlighted open challenges so that RDs will not remain, in practical terms, orphan diseases. © 2017 S. Karger AG, Basel.

  17. China's spent nuclear fuel management: Current practices and future strategies

    International Nuclear Information System (INIS)

    Zhou Yun

    2011-01-01

    Although China's nuclear power industry is relatively young and the management of its spent nuclear fuel is not yet a concern, China's commitment to nuclear energy and its rapid pace of development require detailed analyses of its future spent fuel management policies. The purpose of this study is to provide an overview of China's fuel cycle program and its reprocessing policy, and to suggest strategies for managing its future fuel cycle program. The study is broken into four sections. The first reviews China's current nuclear fuel cycle program and facilities. The second discusses China's current spent fuel management methods and the storage capability of China's 13 operational nuclear power plants. The third estimates China's total accumulated spent fuel, its required spent fuel storage from present day until 2035, when China expects its first commercialized fast neutron reactors to be operational, and its likely demand for uranium resources. The fourth examines several spent fuel management scenarios for the present period up until 2035; the financial cost and proliferation risk of each scenario is evaluated. The study concludes that China can and should maintain a reprocessing operation to meet its R and D activities before its fast reactor program is further developed. - Highlights: → This study provides an overview of China's fuel cycle program and its reprocessing policy.→ This study suggests strategies for managing its future fuel cycle program.→ China will experience no pressure to lessen the burden of spent fuel storage in the next 30 years.→ China should maintain sufficient reprocessing operations to meet its demands for R and D activities.→ China should actively invest on R and D activities of both fuel cycling and fast reactor programs.

  18. 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.

  19. Oligometastatic non-small-cell lung cancer: current treatment strategies

    Directory of Open Access Journals (Sweden)

    Richard PJ

    2016-11-01

    Full Text Available Patrick J Richard, Ramesh Rengan Department of Radiation Oncology, University of Washington, Seattle, WA, USA Abstract: The oligometastatic disease theory was initially described in 1995 by Hellman and Weichselbaum. Since then, much work has been performed to investigate its existence in many solid tumors. This has led to subclassifications of stage IV cancer, which could redefine our treatment approaches and the therapeutic outcomes for this historically “incurable” entity. With a high incidence of stage IV disease, non-small-cell lung cancer (NSCLC remains a difficult cancer to treat and cure. Recent work has proven the existence of an oligometastatic state in NSCLC in terms of properly selecting patients who may benefit from aggressive therapy and experience long-term overall survival. This review discusses the current treatment approaches used in oligometastatic NSCLC and provides the evidence and rationale for each approach. The prognostic factors of many trials are discussed, which can be used to properly select patients for aggressive treatment regimens. Future advances in both molecular profiling of NSCLC to find targetable mutations and investigating patient selection may increase the number of patients diagnosed with oligometastatic NSCLC. As this disease entity increases, it is of utmost importance for oncologists treating NSCLC to be aware of the current treatment strategies that exist and the potential advantages/disadvantages of each. Keywords: oligometastatic, non-small-cell lung cancer, oligoprogressive, treatment

  20. Tokamak plasma current disruption infrared control system

    International Nuclear Information System (INIS)

    Kugel, H.W.; Ulrickson, M.

    1987-01-01

    This patent describes a device for magnetically confining a plasma driven by a plasma current and contained within a toroidal vacuum chamber, the device having an inner toroidal limiter on an inside wall of the vacuum chamber and an arrangement for the rapid prediction and control in real time of a major plasma disruption. The arrangement is described which includes: scanning means sensitive to infrared radiation emanating from within the vacuum chamber, the infrared radiation indicating the temperature along a vertical profile of the inner toroidal limiter. The scanning means is arranged to observe the infrared radiation and to produce in response thereto an electrical scanning output signal representative of a time scan of temperature along the vertical profile; detection means for analyzing the scanning output signal to detect a first peaked temperature excursion occurring along the profile of the inner toroidal limiter, and to produce a detection output signal in repsonse thereto, the detection output signal indicating a real time prediction of a subsequent major plasma disruption; and plasma current reduction means for reducing the plasma current driving the plasma, in response to the detection output signal and in anticipation of a subsequent major plasma disruption

  1. Tuberculosis control in the Americas: current approaches.

    Science.gov (United States)

    Pio, A; Western, K

    1976-01-01

    Tuberculosi remains a serious public health problem in the Americas, and it has not declined as rapidly or as much as experts projected it would in the 1940's. Scientific advances in control of the disease over the last three decades have produced effective chemotherapeutic agents, established the immunizing capacity of BCG vaccine, and demonstrated the superior value of bacteriologic diagnosis in symptomatic individuals over mass community x-ray surveys, which are both inefficient and costly. They have also shown that most cases can be treated on an ambulatory basis, obviating the need for the lengthy hospital stays which have heretofore weighed so heavily on budgets. By standardization of control methods, both for diagnosis and for chemotherapy, these tasks can be taken on by polyvalent staff in the general health services, whose wide coverage places them in a position to reach a much larger segment of the population than that attended by the traditional vertical system. To a greater or lesser degree, all the countries in the Americas are beginning to orient their strategies in this direction, and some of them already have considerable progress to report.

  2. Nonlinear Deadbeat Current Control of a Switched Reluctance Motor

    OpenAIRE

    Rudolph, Benjamin

    2009-01-01

    High performance current control is critical to the success of the switched reluctance motor (SRM). Yet high motor phase nonlinearities in the SRM place extra burden on the current controller, rendering it the weakest link in SRM control. In contrast to linear motor control techniques that respond to current error, the deadbeat controller calculates the control voltage by the current command, phase current, rotor position and applied phase voltage. The deadbeat controller has demonstrated sup...

  3. Sliding Mode Control of Induction Motor Phase Currents

    DEFF Research Database (Denmark)

    Hansen, R.B.; Hattel, T.; Bork, J

    1995-01-01

    Sliding mode control of induction motor phase currents are investigated through development of two control concepts.......Sliding mode control of induction motor phase currents are investigated through development of two control concepts....

  4. NASA Iced Aerodynamics and Controls Current Research

    Science.gov (United States)

    Addy, Gene

    2009-01-01

    This slide presentation reviews the state of current research in the area of aerodynamics and aircraft control with ice conditions by the Aviation Safety Program, part of the Integrated Resilient Aircraft Controls Project (IRAC). Included in the presentation is a overview of the modeling efforts. The objective of the modeling is to develop experimental and computational methods to model and predict aircraft response during adverse flight conditions, including icing. The Aircraft icing modeling efforts includes the Ice-Contaminated Aerodynamics Modeling, which examines the effects of ice contamination on aircraft aerodynamics, and CFD modeling of ice-contaminated aircraft aerodynamics, and Advanced Ice Accretion Process Modeling which examines the physics of ice accretion, and works on computational modeling of ice accretions. The IRAC testbed, a Generic Transport Model (GTM) and its use in the investigation of the effects of icing on its aerodynamics is also reviewed. This has led to a more thorough understanding and models, both theoretical and empirical of icing physics and ice accretion for airframes, advanced 3D ice accretion prediction codes, CFD methods for iced aerodynamics and better understanding of aircraft iced aerodynamics and its effects on control surface effectiveness.

  5. Hierarchical MAS based control strategy for microgrid

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Z.; Li, T.; Huang, M.; Shi, J.; Yang, J.; Yu, J. [School of Information Science and Engineering, Yunnan University, Kunming 650091 (China); Xiao, Z. [School of Electrical and Electronic Engineering, Nanyang Technological University, Western Catchment Area, 639798 (Singapore); Wu, W. [Communication Branch of Yunnan Power Grid Corporation, Kunming, Yunnan 650217 (China)

    2010-09-15

    Microgrids have become a hot topic driven by the dual pressures of environmental protection concerns and the energy crisis. In this paper, a challenge for the distributed control of a modern electric grid incorporating clusters of residential microgrids is elaborated and a hierarchical multi-agent system (MAS) is proposed as a solution. The issues of how to realize the hierarchical MAS and how to improve coordination and control strategies are discussed. Based on MATLAB and ZEUS platforms, bilateral switching between grid-connected mode and island mode is performed under control of the proposed MAS to enhance and support its effectiveness. (authors)

  6. Prevention and Control Strategies to Counter Dengue Virus Infection.

    Science.gov (United States)

    Rather, Irfan A; Parray, Hilal A; Lone, Jameel B; Paek, Woon K; Lim, Jeongheui; Bajpai, Vivek K; Park, Yong-Ha

    2017-01-01

    Dengue is currently the highest and rapidly spreading vector-borne viral disease, which can lead to mortality in its severe form. The globally endemic dengue poses as a public health and economic challenge that has been attempted to suppress though application of various prevention and control techniques. Therefore, broad spectrum techniques, that are efficient, cost-effective, and environmentally sustainable, are proposed and practiced in dengue-endemic regions. The development of vaccines and immunotherapies have introduced a new dimension for effective dengue control and prevention. Thus, the present study focuses on the preventive and control strategies that are currently employed to counter dengue. While traditional control strategies bring temporary sustainability alone, implementation of novel biotechnological interventions, such as sterile insect technique, paratransgenesis, and production of genetically modified vectors, has improved the efficacy of the traditional strategies. Although a large-scale vector control strategy can be limited, innovative vaccine candidates have provided evidence for promising dengue prevention measures. The use of tetravalent dengue vaccine (CYD-TDV) has been the most effective so far in treating dengue infections. Nonetheless, challenges and limitation hinder the progress of developing integrated intervention methods and vaccines; while the improvement in the latest techniques and vaccine formulation continues, one can hope for a future without the threat of dengue virus.

  7. Prevention and Control Strategies to Counter Dengue Virus Infection

    Directory of Open Access Journals (Sweden)

    Irfan A. Rather

    2017-07-01

    Full Text Available Dengue is currently the highest and rapidly spreading vector-borne viral disease, which can lead to mortality in its severe form. The globally endemic dengue poses as a public health and economic challenge that has been attempted to suppress though application of various prevention and control techniques. Therefore, broad spectrum techniques, that are efficient, cost-effective, and environmentally sustainable, are proposed and practiced in dengue-endemic regions. The development of vaccines and immunotherapies have introduced a new dimension for effective dengue control and prevention. Thus, the present study focuses on the preventive and control strategies that are currently employed to counter dengue. While traditional control strategies bring temporary sustainability alone, implementation of novel biotechnological interventions, such as sterile insect technique, paratransgenesis, and production of genetically modified vectors, has improved the efficacy of the traditional strategies. Although a large-scale vector control strategy can be limited, innovative vaccine candidates have provided evidence for promising dengue prevention measures. The use of tetravalent dengue vaccine (CYD-TDV has been the most effective so far in treating dengue infections. Nonetheless, challenges and limitation hinder the progress of developing integrated intervention methods and vaccines; while the improvement in the latest techniques and vaccine formulation continues, one can hope for a future without the threat of dengue virus.

  8. A review of current treatment strategies for gestational diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Kristi W Kelley

    2015-07-01

    Full Text Available Approximately 90% of diabetes cases in pregnant women are considered gestational diabetes mellitus (GDM. It is well known that uncontrolled glucose results in poor pregnancy outcomes in both the mother and fetus. Worldwide there are many guidelines with recommendations for appropriate management strategies for GDM once lifestyle modifications have been instituted and failed to achieve control. The efficacy and particularly the safety of other treatment modalities for GDM has been the source of much debate in recent years. Studies that have demonstrated the safety and efficacy of both glyburide and metformin in the management of patients with GDM will be reviewed. There is a lack of evidence with other oral and injectable non-insulin agents to control blood glucose in GDM. The role of insulin will be discussed, with emphasis on insulin analogs. Ideal patient characteristics for each treatment modality will be reviewed. In addition, recommendations for postpartum screening of patients will be described as well as recommendations for use of agents to manage subsequent type 2 diabetes in patients who are breastfeeding.

  9. Managing Air Quality - Control Strategies to Achieve Air Pollution Reduction

    Science.gov (United States)

    Considerations in designing an effective control strategy related to air quality, controlling pollution sources, need for regional or national controls, steps to developing a control strategy, and additional EPA resources.

  10. A comparison of WEC control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bacelli, Giorgio [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Coe, Ryan Geoffrey [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Abdelkhalik, Ossama [Michigan Technological Univ., Houghton, MI (United States); Korde, Umesh A. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Robinett, Rush D. [Michigan Technological Univ., Houghton, MI (United States)

    2016-04-01

    The operation of Wave Energy Converter (WEC) devices can pose many challenging problems to the Water Power Community. A key research question is how to significantly improve the performance of these WEC devices through improving the control system design. This report summarizes an effort to analyze and improve the performance of WEC through the design and implementation of control systems. Controllers were selected to span the WEC control design space with the aim of building a more comprehensive understanding of different controller capabilities and requirements. To design and evaluate these control strategies, a model scale test-bed WEC was designed for both numerical and experimental testing (see Section 1.1). Seven control strategies have been developed and applied on a numerical model of the selected WEC. This model is capable of performing at a range of levels, spanning from a fully-linear realization to varying levels of nonlinearity. The details of this model and its ongoing development are described in Section 1.2.

  11. Current knowledge and treatment strategies for grade II gliomas

    International Nuclear Information System (INIS)

    Narita, Yoshitaka

    2013-01-01

    World Health Organization grade II gliomas (GIIGs) include diffuse astrocytoma, oligodendroglioma, and oligoastrocytoma. GIIG is a malignant brain tumor for which the treatment outcome can still be improved. Review of previous clinical trials found the following: GIIG increased in size by 3-5 mm per year when observed or treated with surgery alone; after pathological diagnosis, the survival rate was increased by early aggressive tumor removal at an earlier stage compared to observation alone; although the prognosis after total tumor removal was significantly better than that after partial tumor removal, half of the patients relapsed within 5 years; comparing postoperative early radiotherapy (RT) and non-early RT after relapse, early RT prolonged progression-free survival (PFS) but did not affect overall survival (OS); local RT of 45 to 64.8 Gy did not impact PFS or OS; in patients with residual tumors, RT combined with chemotherapy (procarbazine plus lomustine plus vincristine) prolonged PFS compared with RT alone but did not affect OS; and poor prognostic factors included astrocytoma, non-total tumor removal, age ≥40 years, largest tumor diameter ≥4-6 cm, tumor crossing the midline, and neurological deficit. To improve treatment outcomes, surgery with functional brain mapping or intraoperative magnetic resonance imaging or chemoradiotherapy with temozolomide is important. In this review, current knowledge regarding GIIG is described and treatment strategies are explored. (author)

  12. Current Research Therapeutic Strategies for Alzheimer’s Disease Treatment

    Directory of Open Access Journals (Sweden)

    Jaume Folch

    2016-01-01

    Full Text Available Alzheimer’s disease (AD currently presents one of the biggest healthcare issues in the developed countries. There is no effective treatment capable of slowing down disease progression. In recent years the main focus of research on novel pharmacotherapies was based on the amyloidogenic hypothesis of AD, which posits that the beta amyloid (Aβ peptide is chiefly responsible for cognitive impairment and neuronal death. The goal of such treatments is (a to reduce Aβ production through the inhibition of β and γ secretase enzymes and (b to promote dissolution of existing cerebral Aβ plaques. However, this approach has proven to be only modestly effective. Recent studies suggest an alternative strategy centred on the inhibition of the downstream Aβ signalling, particularly at the synapse. Aβ oligomers may cause aberrant N-methyl-D-aspartate receptor (NMDAR activation postsynaptically by forming complexes with the cell-surface prion protein (PrPC. PrPC is enriched at the neuronal postsynaptic density, where it interacts with Fyn tyrosine kinase. Fyn activation occurs when Aβ is bound to PrPC-Fyn complex. Fyn causes tyrosine phosphorylation of the NR2B subunit of metabotropic glutamate receptor 5 (mGluR5. Fyn kinase blockers masitinib and saracatinib have proven to be efficacious in treating AD symptoms in experimental mouse models of the disease.

  13. Sports-related concussions: diagnosis, complications, and current management strategies.

    Science.gov (United States)

    Hobbs, Jonathan G; Young, Jacob S; Bailes, Julian E

    2016-04-01

    Sports-related concussions (SRCs) are traumatic events that affect up to 3.8 million athletes per year. The initial diagnosis and management is often instituted on the field of play by coaches, athletic trainers, and team physicians. SRCs are usually transient episodes of neurological dysfunction following a traumatic impact, with most symptoms resolving in 7-10 days; however, a small percentage of patients will suffer protracted symptoms for years after the event and may develop chronic neurodegenerative disease. Rarely, SRCs are associated with complications, such as skull fractures, epidural or subdural hematomas, and edema requiring neurosurgical evaluation. Current standards of care are based on a paradigm of rest and gradual return to play, with decisions driven by subjective and objective information gleaned from a detailed history and physical examination. Advanced imaging techniques such as functional MRI, and detailed understanding of the complex pathophysiological process underlying SRCs and how they affect the athletes acutely and long-term, may change the way physicians treat athletes who suffer a concussion. It is hoped that these advances will allow a more accurate assessment of when an athlete is truly safe to return to play, decreasing the risk of secondary impact injuries, and provide avenues for therapeutic strategies targeting the complex biochemical cascade that results from a traumatic injury to the brain.

  14. Pinning Control Strategy of Multicommunity Structure Networks

    Directory of Open Access Journals (Sweden)

    Chao Ding

    2017-01-01

    Full Text Available In order to investigate the effects of community structure on synchronization, a pinning control strategy is researched in a class of complex networks with community structure in this paper. A feedback control law is designed based on the network community structure information. The stability condition is given and proved by using Lyapunov stability theory. Our research shows that as to community structure networks, there being a threshold hT≈5, when coupling strength bellows this threshold, the stronger coupling strength corresponds to higher synchronizability; vice versa, the stronger coupling strength brings lower synchronizability. In addition the synchronizability of overlapping and nonoverlapping community structure networks was simulated and analyzed; while the nodes were controlled randomly and intensively, the results show that intensive control strategy is better than the random one. The network will reach synchronization easily when the node with largest betweenness was controlled. Furthermore, four difference networks’ synchronizability, such as Barabási-Albert network, Watts-Strogatz network, Erdös-Rényi network, and community structure network, are simulated; the research shows that the community structure network is more easily synchronized under the same control strength.

  15. International pollution control: Cooperative versus noncooperative strategies

    International Nuclear Information System (INIS)

    Dockner, E.J.; Van Long, N.

    1993-01-01

    International pollution control involving two neighboring countries is modeled as a simple two-player dynamic game. Each country produces a good that is consumed by domestic households. Production of each consumption good results in emissions of pollutants. Households in each country derive utility from the consumption of the domestically produced good but incur costs through the total stock of pollution (stock externality). In this setting we characterize cooperative as well as noncooperative pollution control strategies of the governments of the two countries that maximize the discounted stream of net benefits of a representative consumer. It turns out that when the governments are restricted to use linear strategies noncooperative behavior results in overall losses for both countries. If, on the contrary, governments use nonlinear Markov-perfect strategies and the discount rate is small enough a Pareto-efficient steady-state pollution stock can be supported as a differentiable subgame-perfect equilibrium. Thus, the emergence of first-best solutions (cooperative outcomes) does not require any institutional arrangements (threats, retaliation, etc.) but can be brought about through the use of nonlinear Markov-perfect equilibrium strategies. 20 refs., 1 tab

  16. Bioherbicides: Current knowledge on weed control mechanism.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Alqarawi, Abdulaziz A; Abd Allah, Elsayed Fathi

    2018-04-17

    Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Ebola virus outbreak, updates on current therapeutic strategies.

    Science.gov (United States)

    Elshabrawy, Hatem A; Erickson, Timothy B; Prabhakar, Bellur S

    2015-07-01

    Filoviruses are enveloped negative-sense single-stranded RNA viruses, which include Ebola and Marburg viruses, known to cause hemorrhagic fever in humans with a case fatality of up to 90%. There have been several Ebola virus outbreaks since the first outbreak in the Democratic Republic of Congo in 1976 of which, the recent 2013-2015 epidemic in Guinea, Liberia, and Sierra Leone is the largest in recorded history. Within a few months of the start of the outbreak in December 2013, thousands of infected cases were reported with a significant number of deaths. As of March 2015, according to the Centers for Disease Control and Prevention, there have been nearly 25,000 suspected cases, with 15,000 confirmed by laboratory testing, and over 10,000 deaths. The large number of cases and the high mortality rate, combined with the lack of effective Food and Drug Administration-approved treatments, necessitate the development of potent and safe therapeutic measures to combat the current and future outbreaks. Since the beginning of the outbreak, there have been considerable efforts to develop and characterize protective measures including vaccines and antiviral small molecules, and some have proven effective in vitro and in animal models. Most recently, a cocktail of monoclonal antibodies has been shown to be highly effective in protecting non-human primates from Ebola virus infection. In this review, we will discuss what is known about the nature of the virus, phylogenetic classification, genomic organization and replication, disease transmission, and viral entry and highlight the current approaches and efforts, in the development of therapeutics, to control the outbreak. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Internal quality control: planning and implementation strategies.

    Science.gov (United States)

    Westgard, James O

    2003-11-01

    The first essential in setting up internal quality control (IQC) of a test procedure in the clinical laboratory is to select the proper IQC procedure to implement, i.e. choosing the statistical criteria or control rules, and the number of control measurements, according to the quality required for the test and the observed performance of the method. Then the right IQC procedure must be properly implemented. This review focuses on strategies for planning and implementing IQC procedures in order to improve the quality of the IQC. A quantitative planning process is described that can be implemented with graphical tools such as power function or critical-error graphs and charts of operating specifications. Finally, a total QC strategy is formulated to minimize cost and maximize quality. A general strategy for IQC implementation is recommended that employs a three-stage design in which the first stage provides high error detection, the second stage low false rejection and the third stage prescribes the length of the analytical run, making use of an algorithm involving the average of normal patients' data.

  19. Current strategies for the treatment of aneurysmal bone cysts

    Directory of Open Access Journals (Sweden)

    Panagiotis Tsagozis

    2015-12-01

    Full Text Available Aneurysmal bone cysts are benign bone tumors that usually present in childhood and early adulthood. They usually manifest as expansile osteolytic lesions with a varying potential to be locally aggressive. Since their first description in 1942, a variety of treatment methods has been proposed. Traditionally, these tumors were treated with open surgery. Either intralesional surgical procedures or en bloc excisions have been described. Furthermore, a variety of chemical or physical adjuvants has been utilized in order to reduce the risk for local recurrence after excision. Currently, there is a shift to more minimally invasive procedures in order to avoid the complications of open surgical excision. Good results have been reported during percutaneous surgery, or the use of embolization. Recently, sclerotherapy has emerged as a promising treatment, showing effective consolidation of the lesions and functional results that appear to be superior to the ones of open surgery. Lastly, non-invasive treatment, such as pharmaceutical intervention with denosumab or bisphosphonates has been reported to be effective in the management of the disease. Radiotherapy has also been shown to confer good local control, either alone or in conjunction to other treatment modalities, but is associated with serious adverse effects. Here, we review the current literature on the methods of treatment of aneurysmal bone cysts. The indication for each type of treatment along reported outcome of the intervention, as well as potential complications are systematically presented. Our review aims to increase awareness of the different treatment modalities and facilitate decision-making regarding each individual patient.

  20. Optimal breast cancer screening strategies for older women: current perspectives

    Directory of Open Access Journals (Sweden)

    Braithwaite D

    2016-02-01

    Full Text Available Dejana Braithwaite,1 Joshua Demb,1 Louise M Henderson2 1Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, 2Department of Radiology, University of North Carolina, Chapel Hill, NC, USA Abstract: Breast cancer is a major cause of cancer-related deaths among older women, aged 65 years or older. Screening mammography has been shown to be effective in reducing breast cancer mortality in women aged 50–74 years but not among those aged 75 years or older. Given the large heterogeneity in comorbidity status and life expectancy among older women, controversy remains over screening mammography in this population. Diminished life expectancy with aging may decrease the potential screening benefit and increase the risk of harms. In this review, we summarize the evidence on screening mammography utilization, performance, and outcomes and highlight evidence gaps. Optimizing the screening strategy will involve separating older women who will benefit from screening from those who will not benefit by using information on comorbidity status and life expectancy. This review has identified areas related to screening mammography in older women that warrant additional research, including the need to evaluate emerging screening technologies, such as tomosynthesis among older women and precision cancer screening. In the absence of randomized controlled trials, the benefits and harms of continued screening mammography in older women need to be estimated using both population-based cohort data and simulation models. Keywords: aging, breast cancer, precision cancer screening

  1. A randomised controlled trial evaluating IGF1 titration in contrast to current GH dosing strategies in children born small for gestational age: the North European Small-for-Gestational-Age Study.

    Science.gov (United States)

    Jensen, Rikke Beck; Thankamony, Ajay; O'Connell, Susan M; Kirk, Jeremy; Donaldson, Malcolm; Ivarsson, Sten-A; Söder, Olle; Roche, Edna; Hoey, Hilary; Dunger, David B; Juul, Anders

    2014-10-01

    Short children born small for gestational age (SGA) are treated with a GH dose based on body size, but treatment may lead to high levels of IGF1. The objective was to evaluate IGF1 titration of GH dose in contrast to current dosing strategies. In the North European Small-for-Gestational-Age Study (NESGAS), 92 short pre-pubertal children born SGA were randomised after 1 year of high-dose GH treatment (67 μg/kg per day) to three different regimens: high dose (67 μg/kg per day), low dose (35 μg/kg per day) or IGF1 titration. The average dose during the second year of the randomised trial did not differ between the IGF1 titration group (38 μg/kg per day, s.d. 0.019) and the low-dose group (35 μg/kg per day, s.d. 0.002; P=0.46), but there was a wide variation in the IGF1 titration group (range 10-80 μg/kg per day). The IGF1 titration group had significantly lower height gain (0.17 SDS, s.d. 0.18) during the second year of the randomised trial compared with the high-dose group (0.46 SDS, s.d. 0.25), but not significantly lower than the low-dose group (0.23 SDS, s.d. 0.15; P=0.17). The IGF1 titration group had lower IGF1 levels after 2 years of the trial (mean 1.16, s.d. 1.24) compared with both the low-dose (mean 1.76, s.d. 1.48) and the high-dose (mean 2.97, s.d. 1.63) groups. IGF1 titration of GH dose in SGA children proved less effective than current dosing strategies. IGF1 titration resulted in physiological IGF1 levels with a wide range of GH dose and a poorer growth response, which indicates the role of IGF1 resistance and highlights the heterogeneity of short SGA children. © 2014 European Society of Endocrinology.

  2. Current and emerging treatment strategies for Duchenne muscular dystrophy

    Science.gov (United States)

    Mah, Jean K

    2016-01-01

    Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in childhood. It is caused by mutations of the DMD gene, leading to progressive muscle weakness, loss of independent ambulation by early teens, and premature death due to cardiorespiratory complications. The diagnosis can usually be made after careful review of the history and examination of affected boys presenting with developmental delay, proximal weakness, and elevated serum creatine kinase, plus confirmation by muscle biopsy or genetic testing. Precise characterization of the DMD mutation is important for genetic counseling and individualized treatment. Current standard of care includes the use of corticosteroids to prolong ambulation and to delay the onset of secondary complications. Early use of cardioprotective agents, noninvasive positive pressure ventilation, and other supportive strategies has improved the life expectancy and health-related quality of life for many young adults with DMD. New emerging treatment includes viral-mediated microdystrophin gene replacement, exon skipping to restore the reading frame, and nonsense suppression therapy to allow translation and production of a modified dystrophin protein. Other potential therapeutic targets involve upregulation of compensatory proteins, reduction of the inflammatory cascade, and enhancement of muscle regeneration. So far, data from DMD clinical trials have shown limited success in delaying disease progression; unforeseen obstacles included immune response against the generated mini-dystrophin, inconsistent evidence of dystrophin production in muscle biopsies, and failure to demonstrate a significant improvement in the primary outcome measure, as defined by the 6-minute walk test in some studies. The long-term safety and efficacy of emerging treatments will depend on the selection of appropriate clinical end points and sensitive biomarkers to detect meaningful changes in disease progression. Correction of the underlying

  3. Cross Voltage Control with Inner Hysteresis Current Control for Multi-output Boost Converter

    DEFF Research Database (Denmark)

    Nami, Alireza; Zare, Firuz; Blaabjerg, Frede

    2009-01-01

    Multi-output boost (MOB) converter is a novel DC-DC converter unlike the regular boost converter, has the ability to share its total output voltage and to have different series output voltage from a given duty cycle for low and high power applications. In this paper, discrete voltage control...... with inner hysteresis current control loop has been proposed to keep the simplicity of the control law for the double-output MOB converter, which can be implemented by a combination of analogue and logical ICs or simple microcontroller to constrain the output voltages of MOB converter at their reference...... voltages against variation in load or input voltage. The salient features of the proposed control strategy are simplicity of implementation and ease to extend to multiple outputs in the MOB converter. Simulation and experimental results are presented to show the validity of control strategy....

  4. Current vector control challenges in the fight against malaria.

    Science.gov (United States)

    Benelli, Giovanni; Beier, John C

    2017-10-01

    The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance

  5. Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

    Science.gov (United States)

    Sedighi, Iraj; Karimi, Abdollah; Amanati, Ali

    2016-01-01

    Context Universal immunization against Bordetella pertussis has partially controlled the burden of the disease and its transmission. However, according to recent data, the epidemiology of this vaccine-preventable disease has changed. Now, younger infants, adolescents, and adults are at greater risk of infection. This article has studied the interaction between the various factors involved in the changing epidemiology of pertussis and the major obstacles faced by the current strategies in its prevention. Evidence Acquisition In this narrative review, the most recently published sources of information on pertussis control measures, consisting of textbooks and articles, have been reviewed. We focused on the more recent data about the changing epidemiology or pertussis in Scopus through the use of the MeSH-term words [pertussis] or [whooping cough] and [epidemiology] or [outbreak] or [resurgence], but our search was not restricted to this particular strategy; we also tried to find all of the most recent available data in the general field through other means. Results Primary and booster doses of the pertussis vaccine seem to partially control transmission of the disease, but despite the different preventive strategies available, pertussis continues to cause mortality and morbidity among high-risk groups. Conclusions Adding booster doses of acellular pertussis vaccine to the current national immunization practices with whole-cell vaccines for young adults and pregnant women seems to be a good option for controlling mortality and morbidity among high-risk groups such as very young infants. PMID:27729960

  6. Feedforward control strategy for the state-decoupling Stand-alone UPS with LC output filter

    DEFF Research Database (Denmark)

    Lu, Jinghang; Savaghebi, Mehdi; Guerrero, Josep M.

    2017-01-01

    . In order to further increase the load current disturbance rejection capability of the state-decoupling in UPS system, a feedforward control strategy is proposed. In addition, the design principle for the current and voltage regulators are discussed. Simulation and experimental results are provided......In this paper, the disturbance rejection performance of the cascaded control strategy for UPS system is investigated. The comparison of closed loop system performance between conventional cascaded control (CCC) strategy and state-decoupling cascaded control (SDCC) strategy are further explored...

  7. MSM actuators: design rules and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Holz, Benedikt; Janocha, Hartmut [Laboratory of Process Automation (LPA), Saarland University, Saarbruecken (Germany); Riccardi, Leonardo; Naso, David [Department of Electronics and Electrical Science (DEE), Politecnico di Bari (Italy)

    2012-08-15

    Magnetic shape memory (MSM) alloys are comparatively new active materials which can be used for several industrial applications, ranging from precise positioning systems to advanced robotics. Beyond the material research, which deals with the basic thermo-magneto-mechanical properties of the crystals, the design as well as the control of the actuators displacement is an essential challenge. This paper addresses those two topics, trying to give to the reader a useful overview of existing results, but also presents new ideas. First, it introduces and discusses in details some possible designs, with a special emphasis on innovative actuator design concepts which are able to exploit the particular potentialities of MSM elements. The second focus of the paper is on the problem of designing a controller, i.e., an algorithm that allows to obtain a required performance from the actuator. The proposed control strategies try to take into account two main characteristics of MSM elements: the hysteresis and the temperature dependence. The effectiveness of the strategies is emphasized by experimental results performed on a commercially available MSM actuator demonstrator. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Current control necessary for toroidal plasma equilibrium

    International Nuclear Information System (INIS)

    Nagao, S.

    1987-01-01

    It is shown that a significant amount of dipole current is necessary for the plasma equilibrium of toroidal configurations in general. Through the vector product with the poloidal field, this dipole current force has to balance with the hoop force of plasma pressure itself of the annular shape. The measurement of such a current of dipole type may be interesting for the confirmation of the plasma equilibrium in the toroidal system. Moreover it is certained that there is a new mode of a tokamak operation with such a dipole current component and with smaller vertical field than that based on the classical tokamak theory. (author) [pt

  9. Novel strategies for control of fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa

    to highly optimised industrial host strains. The focus of this project is instead on en-gineering of the process. The question to be answered in this thesis is, given a highly optimised industrial host strain, how can we operate the fermentation process in order to maximise the productivity of the system...... (2012). This model describes the fungal processes operated in the fermentation pilot plant at Novozymes A/S. This model is investigated using uncertainty analysis methods in order to as-sess the applicability to control applications. A mechanistic model approach is desirable, as it is a predictive....... This provides a prediction of the future trajectory of the process, so that it is possible to guide the system to the desired target mass. The control strategy is applied on-line at 550L scale in the Novozymes A/S fermentation pilot plant, and the method is challenged with four different sets of process...

  10. Decentralized Coordinated Control Strategy of Islanded Microgrids

    DEFF Research Database (Denmark)

    Wu, Dan

    as grid voltage/frequency regulation. In order to enhance the reliability of overall islanded Microgrid operation, basic functions of coordinated control which taking into account the state of charge (SoC) limitation and power availability of renewable energy sources is implemented in a distributed level...... control strategies in this thesis, in order to promote the decentralization of the overall system. Especially the consensus algorithm based secondary level is investigated in the thesis in order to simplify the communication configuration which only flood information through the neighboring units......Facing the challenges brought by the traditional large power system concerning the environmental and economic issues, along recent years distributed generation is considered as an alternative solution to provide clean energy in a local manner. In this context, Microgrid which performing as a local...

  11. Radioactive demonstration of DWPF product control strategy

    International Nuclear Information System (INIS)

    Andrews, M.K.; Bibler, N.E.

    1992-01-01

    The effectiveness of the product and process control strategies that will be utilized by the Defense Waste Processing Facility (DWPF) was demonstrated during a campaign in the Shielded Cells Facility (SCF) of the Savannah River Technology Center (SRTC). The remotely operated process included the preparation of the melter feed, vitrification in a slurry-fed 1/100th scale melter and analysis of the glass product both for its composition and durability. The campaign processed approximately 10 kg (on a dry basis) of radioactive sludge from Tank 51. This sludge is representative of the first batch of sludge that will be sent to the DWPF for immobilization into borosilicate glass. Additions to the sludge were made based on calculations using the Product Composition Control System (PCCS). Analysis of the glass produced during the campaign showed that a durable glass was produced with a composition similar to that predicted using the PCCS

  12. Neural PID Control Strategy for Networked Process Control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available A new method with a two-layer hierarchy is presented based on a neural proportional-integral-derivative (PID iterative learning method over the communication network for the closed-loop automatic tuning of a PID controller. It can enhance the performance of the well-known simple PID feedback control loop in the local field when real networked process control applied to systems with uncertain factors, such as external disturbance or randomly delayed measurements. The proposed PID iterative learning method is implemented by backpropagation neural networks whose weights are updated via minimizing tracking error entropy of closed-loop systems. The convergence in the mean square sense is analysed for closed-loop networked control systems. To demonstrate the potential applications of the proposed strategies, a pressure-tank experiment is provided to show the usefulness and effectiveness of the proposed design method in network process control systems.

  13. Companies on Facebook and Twitter. Current situation and communication strategies

    Directory of Open Access Journals (Sweden)

    JÁ Pérez Dasilva

    2013-10-01

    Full Text Available Introduction. Given their influence, companies are being forced to integrate social networks in their communication strategies. Objectives. This article aims to provide an overview of the use of Facebook and Twitter by the main commercial brands in Spain and to analyse the communication strategies of the companies that tend to receive more complaints from the public. Method. The study is based on the examination of the social network accounts of the three brands with the highest advertising investment in each of the 15 industry sectors. A total of 5,433 tweets and 3,000 posts were analysed. Conclusions. The study confirmed the massive presence of these companies is the social networks and demonstrated the extreme variability of the number of followers, the traffic and the nature of the information published. However, it was also demonstrated that the use made of the different social networks and the communication strategies required by the different companies are distinguishable and identifiable.

  14. Current Management Strategy for Active Surveillance in Prostate Cancer.

    Science.gov (United States)

    Syed, Jamil S; Javier-Desloges, Juan; Tatzel, Stephanie; Bhagat, Ansh; Nguyen, Kevin A; Hwang, Kevin; Kim, Sarah; Sprenkle, Preston C

    2017-02-01

    Active surveillance has been increasingly utilized as a strategy for the management of favorable-risk, localized prostate cancer. In this review, we describe contemporary management strategies of active surveillance, with a focus on traditional stratification schemes, new prognostic tools, and patient outcomes. Patient selection, follow-up strategy, and indication for delayed intervention for active surveillance remain centered around PSA, digital rectal exam, and biopsy findings. Novel tools which include imaging, biomarkers, and genetic assays have been investigated as potential prognostic adjuncts; however, their role in active surveillance remains institutionally dependent. Although 30-50% of patients on active surveillance ultimately undergo delayed treatment, the vast majority will remain free of metastasis with a low risk of dying from prostate cancer. The optimal method for patient selection into active surveillance is unknown; however, cancer-specific mortality rates remain excellent. New prognostication tools are promising, and long-term prospective, randomized data regarding their use in active surveillance will be beneficial.

  15. The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash; Safi, Sanam; Nielsen, Emil E

    2017-01-01

    by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded...... on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5....... This protocol for a systematic review aims at identifying the best overall treatment strategy for atrial fibrillation and atrial flutter. METHODS: This protocol for a systematic review was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested...

  16. Regenerative Braking Control Strategy of Electric-Hydraulic Hybrid (EHH Vehicle

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2017-07-01

    Full Text Available A novel electric-hydraulic hybrid drivetrain incorporating a set of hydraulic systems is proposed for application in a pure electric vehicle. Models of the electric and hydraulic components are constructed. Two control strategies, which are based on two separate rules, are developed; the maximum energy recovery rate strategy adheres to the rule of the maximization of the braking energy recovery rate, while the minimum current impact strategy adheres to the rule of the minimization of the charge current to the battery. The simulation models were established to verify the effects of these two control strategies. An ABS (Anti-lock Braking System fuzzy control strategy is also developed and simulated. The simulation results demonstrate that the developed control strategy can effectively absorb the braking energy, suppress the current impact, and assure braking safety.

  17. Development of predictive control strategies for building climate control

    OpenAIRE

    NAGPAL, HIMANSHU

    2018-01-01

    APPROVED The rapid growth in energy usage and CO2 emissions has become a critical issue for the whole world. It is noteworthy that buildings are a major contributor to global primary energy consumption. Among building services, use of energy in heating-ventilation-air-conditioning (HVAC) system is particularly significant (about 50\\% of the total building energy consumption). Therefore, the development and implementation of effective control strategies to optimize the operation of HVAC sys...

  18. Nosocomial infections and their control strategies

    Directory of Open Access Journals (Sweden)

    Hassan Ahmed Khan

    2015-07-01

    Full Text Available Nosocomial infections are also known as hospital-acquired/associated infections. National Healthcare Safety Network along with Centers for Disease Control for surveillance has classified nosocomial infection sites into 13 types with 50 infection sites, which are specific on the basis of biological and clinical criteria. The agents that are usually involved in hospital-acquired infections include Streptococcus spp., Acinetobacter spp., enterococci, Pseudomonas aeruginosa, coagulase-negative staphylococci, Staphylococcus aureus, Bacillus cereus, Legionella and Enterobacteriaceae family members, namely, Proteus mirablis, Klebsiella pneumonia, Escherichia coli, Serratia marcescens. Nosocomial pathogens can be transmitted through person to person, environment or contaminated water and food, infected individuals, contaminated healthcare personnel's skin or contact via shared items and surfaces. Mainly, multi-drug-resistant nosocomial organisms include methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa and Klebsiella pneumonia, whereas Clostridium difficile shows natural resistance. Excessive and improper use of broad-spectrum antibiotics, especially in healthcare settings, is elevating nosocomial infections, which not only becomes a big health care problem but also causes great economic and production loss in the community. Nosocomial infections can be controlled by measuring and comparing the infection rates within healthcare settings and sticking to the best healthcare practices. Centers for Disease Control and Prevention provides the methodology for surveillance of nosocomial infections along with investigation of major outbreaks. By means of this surveillance, hospitals can devise a strategy comprising of infection control practices.

  19. Hydrocarbon control strategies for gasoline marketing operations

    Energy Technology Data Exchange (ETDEWEB)

    Norton, R.L.; Sakaida, R.R.; Yamada, M.M.

    1978-05-01

    This informational document provides basic and current descriptions of gasoline marketing operations and methods that are available to control hydrocarbon emissions from these operations. The three types of facilities that are described are terminals, bulk plants, and service stations. Operational and business trends are also discussed. The potential emissions from typical facilities, including transport trucks, are given. The operations which lead to emissions from these facilities include (1) gasoline storage, (2) gasoline loading at terminals and bulk plants, (3) gasoline delivery to bulk plants and service stations, and (4) the refueling of vehicles at service stations. Available and possible methods for controlling emissions are described with their estimated control efficiencies and costs. This report also includes a bibliography of references cited in the text, and supplementary sources of information.

  20. Current Approaches for Control Room I and C Modernization

    International Nuclear Information System (INIS)

    Lopez, Alberto; Jimenez, Alfonso

    2002-01-01

    In general, instrumentation and control (I and C) systems for nuclear power plants were made using analogic systems and relays, since this was the only technology available by the time these systems were designed. This fact impacts on the operational and maintenance capabilities required to these systems. For this reason, nuclear power plants are facing nowadays two challenges: on one hand, the obsolescence of these systems contributes to the increase in the operation and maintenance costs - due to the difficulties for getting spare parts and support from the system vendors -. On the other hand, there has been an increase in the utilities competitiveness due to the electric power market liberalization. All this, of course, along with the commitment to maintain the current safety levels and meet the new requirements and standards that may arise in the near future. The application of current technologies, especially digital technology, solves the obsolescence problems and allows for a more functional and updated human-machine interface. Nevertheless, the cost associated to these modifications makes it necessary to develop strategies to determine which systems need to be modified and how to implement modifications effectively, so that these systems can work jointly with others using different technologies. Other issues inherent to digital technology must be considered, such as verification and validation of the software and of the human-machine interface, which are required for its licensing. This presentation describes the current approaches for I and C modernization, the main reasons, technologies and implementation plans, focusing on the control room and on the impact on operations. The main issues to be considered for developing a specific modernization plan are analysed. The goals and status of the 'Feasibility Study of the Control Room I and C Modernization' are described. This study is currently being developed by Endesa, Iberdrola and Tecnatom, and is included

  1. SP-100 initial startup and restart control strategy

    Science.gov (United States)

    Halfen, Frank J.; Wong, Kwok K.; Switick, Dennis M.; Shukla, Jaikaran N.

    Startup control strategies for SP-100 are described. Revised control and operating strategies are discussed which have been developed and tested using the SP-100 dynamic simulation model Aries-GFS (Generic Flight System).

  2. Thoracic radiotherapy and breath control: current prospects

    International Nuclear Information System (INIS)

    Reboul, F.; Mineur, L.; Paoli, J.B.; Bodez, V.; Oozeer, R.; Garcia, R.

    2002-01-01

    Three-dimensional conformal radiotherapy (3D CRT) is adversely affected by setup error and organ motion. In thoracic 3D CRT, breathing accounts for most of intra-fraction movements, thus impairing treatment quality. Breath control clearly exhibits dosimetric improvement compared to free breathing, leading to various techniques for gated treatments. We review benefits of different breath control methods -i.e. breath-holding or beam gating, with spirometric, isometric or X-ray respiration sensor- and argument the choice of expiration versus inspiration, with consideration to dosimetric concerns. All steps of 3D-CRT can be improved with breath control. Contouring of organs at risk (OAR) and target are easier and more accurate on breath controlled CT-scans. Inter- and intra-fraction target immobilisation allows smaller margins with better coverage. Lung outcome predictors (NTCP, Mean Dose, LV20, LV30) are improved with breath-control. In addition, inspiration breath control facilitates beam arrangement since it widens the distance between OAR and target, and leaves less lung normal tissue within the high dose region. Last, lung density, as of CT scan, is more accurate, improving dosimetry. Our institutions choice is to use spirometry driven, patient controlled high-inspiration breath-hold; this technique gives excellent immobilization results, with high reproducibility, yet it is easy to implement and costs little extra treatment time. Breath control, whatever technique is employed, proves superior to free breathing treatment when using 3D-CRT. Breath control should then be used whenever possible, and is probably mandatory for IMRT. (authors)

  3. Prevention of OHSS: Current strategies and new insights

    Directory of Open Access Journals (Sweden)

    Cristiano E. Busso

    2010-10-01

    Full Text Available Ovarian hyperstimulation syndrome (OHSS is an iatrogenic and potentially life threatening condition that affects young healthy patients. Many strategies have been proposed to prevent this syndrome. However, to avoid OHSS without compromising on IVF outcome is still a challenge. The most important action is to identify patients at risk even before ovarian stimulation is initiated and to give them special attention. Coasting is the most popular method to avoid/minimize OHSS. Cycle cancellation, cryopreservation, GnRH antagonists, GnRH agonists, i.v. albumin are other strategies that can provide some kind of benefit but do not completely avoid both early and late forms of OHSS and/or cannot be applied to every patient. Recent studies demonstrate that dopamine agonists can prevent or minimize OHSS without affecting IVF outcome but clinical protocols are not well established yet.

  4. Stroke Prevention in Atrial Fibrillation: Current Strategies and Recommendations

    Directory of Open Access Journals (Sweden)

    Gerald V. Naccarelli, MD

    2016-02-01

    Full Text Available Stroke is the most common complication of atrial fibrillation (AF. Guidelines recommend anticoagulant treatment in patients with CHA2DS2VASc scores of >2. Registry data suggests that almost half of patients who should be on therapeutic anticoagulation for stroke prevention in AF (SPAF are not. Warfarin and more recently developed agents, the “novel anticoagulants” (NOACs reduce the risk of embolic strokes. In addition, the NOACs also reduce intracranial hemorrhage (ICH by over 50% compared to warfarin. Anticoagulation and bridging strategies involving cardioversion, catheter ablation, and invasive/surgical procedures are reviewed. The development of reversal agents for NOACs and the introduction of left atrial appendage occluding devices will evolve the use of newer strategies for preventing stroke in high risk AF patients.

  5. Current Strategies to Improve the Bioactivity of PEEK

    Science.gov (United States)

    Ma, Rui; Tang, Tingting

    2014-01-01

    The synthetic thermoplastic polymer polyetheretherketone (PEEK) is becoming a popular component of clinical orthopedic and spinal applications, but its practical use suffers from several limitations. Although PEEK is biocompatible, chemically stable, radiolucent and has an elastic modulus similar to that of normal human bone, it is biologically inert, preventing good integration with adjacent bone tissues upon implantation. Recent efforts have focused on increasing the bioactivity of PEEK to improve the bone-implant interface. Two main strategies have been used to overcome the inert character of PEEK. One approach is surface modification to activate PEEK through surface treatment alone or in combination with a surface coating. Another strategy is to prepare bioactive PEEK composites by impregnating bioactive materials into PEEK substrate. Researchers believe that modified bioactive PEEK will have a wide range of orthopedic applications. PMID:24686515

  6. 40 CFR 123.46 - Individual control strategies.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Individual control strategies. 123.46... PROGRAM REQUIREMENTS Transfer of Information and Permit Review § 123.46 Individual control strategies. (a..., approval, and implementation an individual control strategy for each point source identified by the State...

  7. Radioactive demonstration of DWPF product control strategy

    International Nuclear Information System (INIS)

    Andrews, M.K.; Bibler, N.E.

    1994-01-01

    The Defense Waste Processing Facility at the Savannah River Site (SRS) will vitrify high-level nuclear waste into borosilicate glass. The waste will be mixed with properly formulated glass-making frit and fed to a melter at 1150 degrees C. Process reliability and product quality are ensured by proper control of the melter feed composition. The effectiveness of the product and process control strategies that will be utilized by the Defense Waste Processing Facility (DWPF) was demonstrated during a campaign in the Shielded Cells Facility of the Savannah River Technology Center (SRTC). The remotely operated process included the preparation of the melter feed, vitrification in a slurry-fed 1/100th scale melter an analysis of the glass product both for its composition an durability. The campaign processed approximately 10 kg (on a dry basis) of radioactive sludge from Tank 51. This sludge is representative of the first batch of sludge that will be sent to the DWPF for immobilization into borosilicate glass. Additions to the sludge were made based on calculations using the Product Composition Control System (PCCS). Analysis of the glass produced during the campaign showed that a durable glass was produced with a composition very close to that predicted using the PCCS. 10 refs., 4 tabs

  8. Cost Effectiveness Analysis of Optimal Malaria Control Strategies in Kenya

    Directory of Open Access Journals (Sweden)

    Gabriel Otieno

    2016-03-01

    Full Text Available Malaria remains a leading cause of mortality and morbidity among the children under five and pregnant women in sub-Saharan Africa, but it is preventable and controllable provided current recommended interventions are properly implemented. Better utilization of malaria intervention strategies will ensure the gain for the value for money and producing health improvements in the most cost effective way. The purpose of the value for money drive is to develop a better understanding (and better articulation of costs and results so that more informed, evidence-based choices could be made. Cost effectiveness analysis is carried out to inform decision makers on how to determine where to allocate resources for malaria interventions. This study carries out cost effective analysis of one or all possible combinations of the optimal malaria control strategies (Insecticide Treated Bednets—ITNs, Treatment, Indoor Residual Spray—IRS and Intermittent Preventive Treatment for Pregnant Women—IPTp for the four different transmission settings in order to assess the extent to which the intervention strategies are beneficial and cost effective. For the four different transmission settings in Kenya the optimal solution for the 15 strategies and their associated effectiveness are computed. Cost-effective analysis using Incremental Cost Effectiveness Ratio (ICER was done after ranking the strategies in order of the increasing effectiveness (total infections averted. The findings shows that for the endemic regions the combination of ITNs, IRS, and IPTp was the most cost-effective of all the combined strategies developed in this study for malaria disease control and prevention; for the epidemic prone areas is the combination of the treatment and IRS; for seasonal areas is the use of ITNs plus treatment; and for the low risk areas is the use of treatment only. Malaria transmission in Kenya can be minimized through tailor-made intervention strategies for malaria control

  9. Numerical simulation of energy efficiency measures: control and operational strategies

    International Nuclear Information System (INIS)

    Ardehali, M. M.

    2006-01-01

    The inherent limitation in performance of building envelop components and heating ventilating and air conditioning (HVAC) equipment necessitates the examination of operational strategies for improvement in energy-efficient operation of buildings. Due to the ease of installation and increasing availability of electronic controllers, operational strategies that could be programmed are of particular interest. The Iowa Energy Center in the US has taken the initiative to conduct the necessary assessment of current HVAC technology and the commonly-used operational strategies for commercial and industrial buildings, as applied to the midwestern part of the country, with weather and energy cost data for Des Moines, Iowa. The first part of this study focused on the energy consumption and cost effectiveness of HVAC systems. The objectives of the second part is concerned with examination of various operational strategies, namely, night purge (NP), fan optimum start and stop (OSS), condenser water reset (CWR), and chilled water reset (CHWR) applied to order and newer-type commercial office buildings. The indoor air quality requirement are met and the latest applicable energy rates from local utility companies are used. The results show that, in general, NP is not an effective strategy in buildings with low thermal mass storage, OSS reduced fan energy, and CWR and CHWR could be effective and require chillers with multi-stage unloading characteristics. The most operationally efficient strategies are the combination of OSS, CWR, and CHWR for the older-type building, and OSS for the newer-type building. Economically, the most effective is the OSS strategy for the older-type building and the CHWR strategy for the newer-type building.(Author)

  10. Speed controller for an alternating - current motor

    International Nuclear Information System (INIS)

    Bolie, V.W.

    1984-01-01

    A controller for a multi-phase ac motor that is subject to a large inertial load, e.g. an induction motor driving a heavy spinning rotor of a neutron chopper that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal Esub(L) having a meandering line frequency, includes a sensor which provides a feedback pulse train representative of the actual speed of the motor which is compared (by counting clock pulses between feedback pulses) with a reference clock signal in a computing unit to provide a motor control signal Esub(c). The motor control signal is a weighted linear sum of a speed error signal, a phase error signal, and a drift error signal, the magnitudes of which are recalculated and updated with each revolution of the motor shaft. The speed error signal is constant for large speed errors but highly sensitive to small speed errors. The stator windings of the motor are driven by variable-frequency power amplifiers which are controlled by the motor control signal Esub(c) via PROMs which store digital representations of sine and cosine waveforms in quadrature. (author)

  11. Intervention strategies for control of foodborne pathogens

    Science.gov (United States)

    Juneja, Vijay K.

    2004-03-01

    The increasing numbers of illnesses associated with foodborne pathogens such as Listeria monocytogenes and Escherichia coli O157:H7, has renewed concerns about food safety because of consumer preferences for minimally processed foods that offer convenience in availability and preparation. Accordingly, the need for better control of foodborne pathogens has been paramount in recent years. Mechanical removal of microorganisms from food can be accomplished by centrifugation, filtration, trimming and washing. Cleaning and sanitation strategies can be used for minimizing the access of microorganisms in foods from various sources. Other strategies for control of foodborne pathogens include established physical microbiocidal treatments such as ionizing radiation and heating. Research has continued to demonstrate that food irradiation is a suitable process to control and possibly eliminate foodborne pathogens, for example Listeria monocytogenes and Escherichia coli O157:H7, from a number of raw and cooked meat and poultry products. Heat treatment is the most common method in use today for the inactivation of microorganisms. Microorganisms can also be destroyed by nonthermal treatments, such as application of high hydrostatic pressure, pulsed electric fields, oscillating magnetic fields or a combination of physical processes such as heat-irradiation, or heat-high hydrostatic pressure, etc. Each of the non-thermal technologies has specific applications in terms of the types of food that can be processed. Both conventional and newly developed physical treatments can be used in combination for controlling foodborne pathogens and enhancing the safety and shelf life of foods. Recent research has focused on combining traditional preservation factors with emerging intervention technologies. However, many key issues still need to be addressed for combination preservation factors or technologies to be useful in the food industry to meet public demands for foods with enhanced safety

  12. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2001-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... without further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as experimentally on the actual induction motor, both in open-loop current control and when an outer...... speed control loop is closed around the current loop...

  13. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...... is closed around the current loop....

  14. [Harm reduction strategy in tobacco control].

    Science.gov (United States)

    Gorini, Giuseppe

    2011-01-01

    .Thus, California Department of Health Services prohibits promotion of snus and medicinal nicotine as a harm reduction strategy. However, the US Federal Family Smoking Prevention and Tobacco Control Act, signed by President Obama in 2009, places tobacco products under FDA jurisdiction: FDA must define criteria for lowering carcinogens and toxicants in tobacco products, making more available medicinal nicotine, evaluating PREPs, creating a federal Tobacco Control Agency.Which approaches is Italy going to follow?

  15. Current Therapeutic Strategies and Novel Approaches in Osteosarcoma

    International Nuclear Information System (INIS)

    Ando, Kosei; Heymann, Marie-Françoise; Stresing, Verena; Mori, Kanji; Rédini, Françoise; Heymann, Dominique

    2013-01-01

    Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies

  16. Current strategies in surgical myocardial revascularization: Indian perspective

    Directory of Open Access Journals (Sweden)

    Sameer Kumar

    2013-01-01

    A retrospective analysis was carried out of 172 patients who underwent CABG at INHS Asvini between 01 Jan 2008 and 31 May 2013.39% had Left Main Coronary artery disease, 85% patient had triple vessel disease, 56% were diabetics, 12% had undergone stenting in recent past. Beating heart strategy was used in 10%, average no of grafts per patient was 2.3 with LIMA and Radial artery being used as a conduit in 84% and 4% respectively. 4.6% patients succumbed in post-operative period.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-07-12

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

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

    International Nuclear Information System (INIS)

    1976-01-01

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

  19. Iaverage current mode (ACM) control for switching power converters

    OpenAIRE

    2014-01-01

    Providing a fast current sensor direct feedback path to a modulator for controlling switching of a switched power converter in addition to an integrating feedback path which monitors average current for control of a modulator provides fast dynamic response consistent with system stability and average current mode control. Feedback of output voltage for voltage regulation can be combined with current information in the integrating feedback path to limit bandwidth of the voltage feedback signal.

  20. Designing single phase Current-Programmed-Controlled rectifiers by harmonic currents

    DEFF Research Database (Denmark)

    Andersen, Gert Karmisholt; Blaabjerg, Frede

    2002-01-01

    The grid current harmonics of a Current-Programmed-Controlled (CPC) pfc rectifier strongly depends on the choice of switching frequency and switching inductance. This paper describes a new simple and vert fast method to calculate the grid current of a CPC controlled pfc converter. The method...

  1. Federal Wildfire Activities. Current Strategy and Issues Needing Attention

    National Research Council Canada - National Science Library

    1999-01-01

    Concerned about the rising costs of preparing for and controlling wildfires, you asked us to provide information on how the Forest Service and the Bureau of Land Management manage their wildfire programs...

  2. Oral insulin delivery: existing barriers and current counter-strategies.

    Science.gov (United States)

    Gedawy, Ahmed; Martinez, Jorge; Al-Salami, Hani; Dass, Crispin R

    2018-02-01

    The chronic and progressive nature of diabetes is usually associated with micro- and macrovascular complications where failure of pancreatic β-cell function and a general condition of hyperglycaemia is created. One possible factor is failure of the patient to comply with and adhere to the prescribed insulin due to the inconvenient administration route. This review summarizes the rationale for oral insulin administration, existing barriers and some counter-strategies trialled. Oral insulin mimics the physiology of endogenous insulin secreted by pancreas. Following the intestinal absorption of oral insulin, it reaches the liver at high concentration via the portal vein. Oral insulin on the other hand has the potential to protect pancreatic β-cells from autoimmune destruction. Structural modification, targeting a particular tissue/receptor, and the use of innovative pharmaceutical formulations such as nanoparticles represent strategies introduced to improve oral insulin bioavailability. They showed promising results in overcoming the hurdles facing oral insulin delivery, although delivery is far from ideal. The use of advanced pharmaceutical technologies and further research in particulate carrier system delivery predominantly nanoparticle utilization would offer useful tools in delivering insulin via the oral route which in turn would potentially improve diabetic patient compliance to insulin and the overall management of diabetes. © 2017 Royal Pharmaceutical Society.

  3. The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash J; Feinberg, Joshua; Nielsen, Emil E

    2017-01-01

    -effect meta-analysis and chose the most conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. Statistical heterogeneity was assessed by visual inspection of forest plots and by calculating inconsistency (I2) for traditional meta-analyses and diversity...... (D2) for TSA. Sensitivity analyses and subgroup analyses were conducted to explore the reasons for substantial statistical heterogeneity. We assessed the risk of publication bias in meta-analyses consisting of 10 trials or more with tests for funnel plot asymmetry. We used GRADE to assess the quality...... of the body of evidence. RESULTS: 25 randomized clinical trials (n = 9354 participants) were included, all of which were at high risk of bias. Meta-analysis showed that rhythm control strategies versus rate control strategies significantly increased the risk of a serious adverse event (risk ratio (RR), 1...

  4. Gestational Diabetes Mellitus: a review of current diagnostic strategies concepts

    Directory of Open Access Journals (Sweden)

    Juan Sebastián Frías-Ordoñez

    2016-10-01

    Full Text Available Gestational diabetes mellitus (GDM is a state of carbohydrate intolerance that is first recognized during pregnancy. The initial criteria for diagnosis were established more than 50 years ago by O’Sullivan & Mahan, and since then, some modifications have been made. Currently, diagnosis considers two methods: the onestep approach, consisting of an oral glucose tolerance test (OGTT for 2 hours with 75g of glucose, and the two-step approach, which involves an initial screening test with 50g of glucose and OGTT with 100g of glucose if screening is positive. Both diagnostic approaches have been justified by expert consensus; however, an absolute concept about the method to be applied has not been established yet. To select a method, the clinician must take into account various factors. This paper proposes a historical overview and the presentation of the current status of GDM diagnosis.

  5. Indirect thermal control for improved reliability of Modular Multilevel Converter by utilizing circulating current

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Ma, Ke; Loh, Poh Chiang

    2015-01-01

    semiconductor devices are comprehensively investigated. Also a novel control strategy by utilizing the circulating current is proposed to enhance the reliability performance of MMC in order to limit the amplitude of thermal cycles. It is concluded that the circulating current may change the losses and thermal...

  6. Indoor radon and decay products: Concentrations, causes, and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Nero, A.V.; Gadgil, A.J.; Nazaroff, W.W.; Revzan, K.L.

    1990-11-01

    This report is another in the on going technical report series that addresses various aspects of the DOE Radon Research Program. It provides an overview of what is known about the behavior of radon and its decay products in the indoor environment and examines the manner in which several important classes of factors -- structural, geological, and meteorological -- affect indoor radon concentrations. Information on US indoor radon concentrations, currently available monitoring methods and novel radon control strategies are also explored. 238 refs., 22 figs., 9 tabs.

  7. Current control system for superconducting coils of LHD

    International Nuclear Information System (INIS)

    Chikaraishi, H.; Yamada, S.; Inoue, T.

    1996-01-01

    This paper introduce a coil current control system of the LHD. The main part of this system consists of two VME based real time computers and a risc based work station which are connected by optical fiber link. In this computer system, a coil current controller for steady state operation of LHD which based on a state variable control theory is installed. Also advanced current control scheme, which are now developing for dynamic current control in phase II operation of LHD, are introduced. (author)

  8. Current status and some aspects of the future energy strategy

    International Nuclear Information System (INIS)

    Antic, D. P.; Sokcic-Kostic, M. S. . E-mail address of corresponding author: dragon@vin.bg.ac.yu; Antic, D.)

    2005-01-01

    Current status of the energy production and of the energy sources in the world, European Union, Serbia and Montenegro and the Balkan states is analyzed. Some trends in the energy consumption and productions in some European states are analyzed. Some problems of the Serbia and Montenegro energy production system are compared with situation in neighbor states, Germany, and European Union. At present, anywhere in the world, the nuclear power in on the defensive. In some countries it has been even outlawed. Some parameters show that nuclear power, on the global scale and during this century at least, is absolutely essential and reasons for revival of nuclear energy are realistic. (author)

  9. Maternal mortality in India: current status and strategies for reduction.

    Science.gov (United States)

    Prakash, A; Swain, S; Seth, A

    1991-12-01

    The causes (medical, reproductive factors, health care delivery system, and socioeconomic factors) of maternal mortality in India and strategies for reducing maternal mortality are presented. Maternal mortality rates (MMR) are very high in Asia and Africa compared with Northern Europe's 4/100,000 live births. An Indian hospital study found the MMR to be 4.21/1000 live births. 50-98% of maternal deaths are caused by direct obstetric causes (hemorrhage, infection, and hypertensive disorders, ruptured uterus, hepatitis, and anemia). 50% of maternal deaths due to sepsis are related to illegal induced abortion. MMR in India has not declined significantly in the past 15 years. Age, primi and grande multiparity, unplanned pregnancy, and related illegal abortion are the reproductive causes. In 1985 WHO reported that 63-80% of maternal deaths due to direct obstetric causes and 88-98% of all maternal deaths could probably have been prevented with proper handling. In India, coordination between levels in the delivery system and fragmentation of care account for the poor quality of maternal health care. Mass illiteracy is another cause. Effective strategies for reducing the MMR are 1) to place a high priority on maternal and child health (MCH) services and integrate vertical programs (e.g., family planning) related to MCH; 2) to give attention to care during labor and delivery, which is the most critical period for complications; 3) to provide community-based delivery huts which can provide a clean and safe delivery place close to home, and maternity waiting rooms in hospitals for high risk mothers; 4) to improve the quality of MCH care at the rural community level (proper history taking, palpation, blood pressure and fetal heart screening, risk factor screening, and referral); 5) to improve quality of care at the primary health care level (emergency care and proper referral); 6) to include in the postpartum program MCH and family planning services; 7) to examine the

  10. Feedback control strategies for the Liu chaotic system

    International Nuclear Information System (INIS)

    Zhu Congxu; Chen Zhigang

    2008-01-01

    This Letter proposed three strategies of the dislocated feedback control, enhancing feedback control and speed feedback control of the Liu chaotic system to its unstable equilibrium points. It is found that the coefficients of enhancing feedback control and speed feedback control are smaller than those of ordinary feedback control, so, the complexity and cost of the system control are reduced. Theoretical analysis and numerical simulation are given, revealing the effectiveness of these strategies

  11. A Current Limiting Strategy to Improve Fault Ride-Through of Inverter Interfaced Autonomous Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Guerrero, Josep M.

    2017-01-01

    With high penetration of distributed energy resources (DER), fault management strategy is of great importance for the distribution network operation. The objective of this paper is to propose a current and voltage limiting strategy to enhance fault ride-through (FRT) capability of inverter...... for both four- and three-wire configurations. The proposed strategy provides high voltage and current quality during overcurrent conditions, which is necessary for sensitive loads. Several time-domain simulation studies are conducted to investigate the FRT capability of the proposed strategy against both...... asymmetrical and symmetrical faults. Moreover, the proposed method is tested on the CIGRE benchmark microgrid to demonstrate the effectiveness of the proposed limiting strategy....

  12. Building Visual Artists’ Resilience Capabilities: Current Educator Strategies and Methods

    Directory of Open Access Journals (Sweden)

    Eileen Maree Siddins

    2016-07-01

    Full Text Available Enrolments in higher education programs in the creative and performing arts are increasing in many countries. Yet graduates of these degrees, who enter the broad sector known as the creative industries, face particular challenges in terms of securing long-term and sustainable employment. In addition, creative and performing artists face a range of mental challenges, caused by such factors as: the solitary nature of much creative practice, critical feedback by audiences and gatekeepers, or the general pressures associated with maintaining artistic relevance or integrity. The concepts of resilience and professional wellbeing are therefore highly relevant to those who pursue a career in creative industries, and while there has been an emerging body of work in this area, to date it has focussed on the performing arts area (e.g. music, theatre. Hence, in order to expand knowledge relevant to resilience and artists, this paper sets out to explore the extent to which current educators in the Australian context specifically address these issues within higher visual arts curricula; specifically the areas of illustration, design, film and photography. This was achieved via interviews with seventeen current academics working in these areas. The findings propose that higher education providers of programs in the visual arts consider placing a stronger emphasis on the embedded development of resilience and professional wellbeing capacities.

  13. Reference materials for molecular diagnostics: Current achievements and future strategies.

    Science.gov (United States)

    Jing, Rongrong; Wang, Huimin; Ju, Shaoqing; Cui, Ming

    2018-06-01

    Molecular diagnoses have become more widespread in many areas of laboratory medicine where qualitative or quantitative approaches are used to detect nucleic acids. The increasing number of assay methods and the targets for molecular diagnostics contribute to variability in the test results among clinical laboratories. Thus, reference materials (RMs) are required to enhance the comparability of results. This review focuses on the definition of RMs as well as the production and characteristics of higher order RMs from different organizations and their future strategies. We describe the recent progress in RMs, including the definition of RMs by the Joint Committee for Guides in Metrology, as well as the production and characteristics of higher order RMs by international official bodies. There is an urgent need for RMs in nucleic acid testing, especially higher order RMs. To advance the harmonization and standardization of clinical nucleic acid detection, cooperation between the above organizations is proposed and different approaches to higher order RMs development are also needed. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  14. Oncolytic Immunotherapy: Conceptual Evolution, Current Strategies, and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Zong Sheng Guo

    2017-05-01

    Full Text Available The concept of oncolytic virus (OV-mediated cancer therapy has been shifted from an operational virotherapy paradigm to an immunotherapy. OVs often induce immunogenic cell death (ICD of cancer cells, and they may interact directly with immune cells as well to prime antitumor immunity. We and others have developed a number of strategies to further stimulate antitumor immunity and to productively modulate the tumor microenvironment (TME for potent and sustained antitumor immune cell activity. First, OVs have been engineered or combined with other ICD inducers to promote more effective T cell cross-priming, and in many cases, the breaking of functional immune tolerance. Second, OVs may be armed to express Th1-stimulatory cytokines/chemokines or costimulators to recruit and sustain the potent antitumor immunity into the TME to focus their therapeutic activity within the sites of disease. Third, combinations of OV with immunomodulatory drugs or antibodies that recondition the TME have proven to be highly promising in early studies. Fourth, combinations of OVs with other immunotherapeutic regimens (such as prime-boost cancer vaccines, CAR T cells; armed with bispecific T-cell engagers have also yielded promising preliminary findings. Finally, OVs have been combined with immune checkpoint blockade, with robust antitumor efficacy being observed in pilot evaluations. Despite some expected hurdles for the rapid translation of OV-based state-of-the-art protocols, we believe that a cohort of these novel approaches will join the repertoire of standard cancer treatment options in the near future.

  15. Unresectable liver metastases in colorectal cancer: review of current strategies.

    Science.gov (United States)

    Sueur, Benjamin; Pellerin, Olivier; Voron, Thibault; Pointet, Anne L; Taieb, Julien; Pernot, Simon

    2016-12-01

    The objective of the treatment of colorectal cancer patients with unresectable liver metastases should be clearly defined at the outset. Potentially resectable patients should be distinguished from clearly unresectable patients. In defining resectability, it is important to take into account both anatomic characteristics and patient characteristic (comorbidities, symptoms, age). According to this evaluation, treatment should be tailored to each patient. The most widely accepted standard is doublet cytotoxic regimen plus biotherapy (anti-EGFR or anti-VEGF antibodies according to RAS status, but some patients could benefit from an intensified regimen, as triplet chemotherapy ± bevacizumab, or intraarterial treatments (hepatic arterial infusion, radioembolization or chemoembolization), in order to allow resectability. It is therefore very important to discuss the treatments with a multidisciplinary team, including an experienced surgeon, an interventional radiologist and an oncologist. On the other hand, some patients could benefit in terms of quality of life and decreased toxicity from less intense treatment when resection is not an objective. First-line monotherapy or a maintenance strategy with biotherapy and/or cytotoxics could be discussed with these patients, and treatment holidays should be considered in selected patients. Finally, in patients with secondary resection of liver metastases, specificity should be considered in choosing the best adjuvant treatment, such as response to preoperative treatment and individual risk of relapse, which many in some cases justify intensification with hepatic arterial infusion in an adjuvant setting.

  16. 40 CFR 52.2088 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2088... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the Rhode Island Department of... revised text is set forth as follows: § 52.2088 Control strategy: Ozone. (c) Determination of Attainment...

  17. Book Review: Current Issues in International Human Resource Management and Strategy Research

    DEFF Research Database (Denmark)

    Gretzinger, Susanne

    2009-01-01

    The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer.......The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer....

  18. Current technics and management strategy for Pu-contaminated wastes at PNC

    International Nuclear Information System (INIS)

    1981-02-01

    Power Reactor and Nuclear Fuel Development Corporation (PNC) was designated as a leading organization for the Pu-contaminated waste technology program in Japan. For this purpose, number of efforts in the research and development are proceeding. That is, Pu-contaminated waste technology including volume reduction system and the immobilization of wastes is being developed. The design of a Pu-contaminated waste treatment facility (PWTF) is being made for the demonstration of the technology developed. Studies are in progress to find the criteria for waste products in disposal. The current procedures and strategy for the management of Pu-contaminated wastes at PNC are described as follows: current and future management; technology development including controlled air incineration, acid digestion, immobilization melting, dismantling, and liquid waste treatment; the Pu-contaminated waste treatment facility. (J.P.N.)

  19. Impedance Based Analysis of DFIG Stator Current Unbalance and Distortion Suppression Strategies

    DEFF Research Database (Denmark)

    Song, Yipeng; Zhou, Dao; Blaabjerg, Frede

    2016-01-01

    The control strategies of Doubly Fed Induction Generator (DFIG) system output current unbalance and distortion suppression have been well investigated in detail, with the implementation of two kinds of resonant regulators, i.e., conventional Resonance (R) regulator or Vector Proportional Integral...... reshaping though the introduction of R and VPI regulator. It is pointed out that, when implemented in the DFIG system output current unbalance and distortion suppression, the VPI regulator (equivalent to the combination of virtual positive inductor and virtual positive resistor) has two advantages over R...... regulator (equivalent to the combination of virtual positive resistor and virtual negative inductor), i.e., better high order harmonic distortion suppression. The theoretical analysis and MATLAB simulation results have validated the correctness of this conclusion....

  20. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter...

  1. Primary prevention of diabetes mellitus: current strategies and future trends

    Directory of Open Access Journals (Sweden)

    Prasanta K. Bhattacharya

    2016-04-01

    Full Text Available Aim of this paper is to find evidence for primary prevention of type-2 diabetes mellitus (T2DM from epidemiological studies and clinical trials, and the feasibility of applying these interventions in resource limited countries. T2DM, which accounts for more than nine-tenths of all diabetics, results from inadequate insulin secretion or underlying insulin resistance. The prevalence of diabetes, mainly T2DM, has increased rapidly during the last few decades worldwide. Since the genetic background is unlikely to change during this short time period, the growing epidemic of T2DM is more likely due to changes in environmental or lifestyle risk factors including obesity, physical inactivity, smoking, alcohol and stress. The scope and feasibility for primary prevention of T2DM is based on elimination of these risk factors. This evidence that T2DM is preventable comes from epidemiologic studies and clinical trials of effect of lifestyle changes and drugs in development of T2DM. The positive effects are more profound and safer with lifestyle modifications (LSM compared to medications. This is shown to be effective globally, across various ethnicities and races and sustainable on long-term follow-up. However, there is a major challenge in translating this evidence into economically viable and sustained community programs, as these LSM interventions are expensive, even from western standards point of view. Future plan should focus on health education of the public, improving the national capacity to detect and manage the environmental risks including strategies to reduce stress, and development of innovative, cost effective, and scalable methodologies.

  2. Strategy to Ensure Institutional Control Implementation at Superfund Sites

    Science.gov (United States)

    This document sets forth EPA’s strategy (Strategy) for ensuring that institutional controls (ICs) are successfully implemented at Superfund sites, with an emphasis on evaluating ICs at sites where all construction of all remedies is complete (construction complete sites).

  3. An adaptive control strategy of converter based DG to maintain protection coordination in distribution system

    DEFF Research Database (Denmark)

    Su, Chi; Liu, Zhou; Chen, Zhe

    2014-01-01

    of network protection devices. As a protection measure commonly used in distribution network, recloser-fuse coordination could suffer from this impact. Research work has been conducted to deal with this problem by modifying the control strategy of the DG converters during faults. These solutions generally...... reduce the current output from the converters during faults so as to mitigate the influence on protection coordination. However, converter current reduction may not be necessary for all types of faults. This paper proposes a converter control strategy with adaptivity to different fault types and also non......-fault voltage drop events. This control strategy is validated by simulations in DIgSILENT PowerFactory....

  4. An appraisal of current dysphagia diagnosis and treatment strategies.

    Science.gov (United States)

    Kaindlstorfer, Adolf; Pointner, Rudolph

    2016-08-01

    Dysphagia is a common, serious health problem with a wide variety of etiologies and manifestations. This review gives a general overview of diagnostic and therapeutic options for oropharyngeal as well as esophageal swallowing disorders respecting the considerable progress made over recent years. Diagnosis can be challenging and requires expertise in interpretation of symptoms and patient history. Endoscopy, barium radiography and manometry are still the diagnostic mainstays. Classification of esophageal motor-disorders has been revolutionized with the introduction of high-resolution esophageal pressure topography and a new standardized classification algorithm. Automated integrated impedance manometry is a promising upcoming tool for objective evaluation of oropharyngeal dysphagia, in non-obstructive esophageal dysphagia and prediction of post fundoplication dysphagia risk. Impedance planimetry provides new diagnostic information on esophageal and LES-distensibility and allows controlled therapeutic dilatation without the need for radiation. Peroral endoscopic myotomy is a promising therapeutic approach for achalasia and spastic motility disorders.

  5. Force Control Strategies in Hydraulically Actuated Legged Robots

    Directory of Open Access Journals (Sweden)

    Hector Montes

    2016-03-01

    Full Text Available In this contribution, several strategies of force control have been proposed to be implemented and evaluated in ROBOCLIMBER, a quadruped robot of large dimensions. A first group of strategies proposed in this paper is based on impedance control, which is intended to adapt the foot-ground contact forces according to the experimentally specified damping ratio and the undamped natural frequency. A second control strategy of interest for many practical cases is called the parallel force/position control, which has one inner loop position control and two external control loops, one of force and another of position. A third group of control strategies is the posture stabilization for ROBOCLIMBER using the feedback of the ZMP calculation and the position of its legs. Finally, a control strategy for the control of a quasi-static gait using ZMP feedback is proposed and tested by simulation.

  6. Improved Control Strategy for Microgrid Ultracapacitor Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2014-12-01

    Full Text Available Ultracapacitors (UCs, with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an energy storage system (ESS based on ultracapacitors in the context of grid-connected microgrids. The ESS is composed of DC/AC and DC/DC converters tied by a dc link. An improved dynamic model for the ESS is proposed. Based on the proposed model a Proportional-Integral-Resonant (PIR DC link voltage controller is proposed to maintain the DC link voltage through the charging-discharging control of ultracapacitors, capable of working properly under all operating conditions. An extra double frequency component is injected into the UC current by a R controller to dynamically compensate for DC instantaneous power and double frequency AC instantaneous power due to unbalanced grid conditions and disturbances. This feature maintains the DC link voltage constant under unbalanced conditions and increases the degrees of freedom of the DC/AC converter and thus facilitates the application of UCs in microgrids. Simulation and experimental results verify the effectiveness of the proposed control strategy.

  7. Solar shading control strategy for office buildings in cold climate

    DEFF Research Database (Denmark)

    Røseth Karlsen, Line; Heiselberg, Per Kvols; Bryn, Ida

    2016-01-01

    Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated.......Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated....

  8. Control strategies for vehicular NOx emissions in Guangzhou, China

    International Nuclear Information System (INIS)

    Shao Min; Zhang Yuanhang; Raufer, Roger

    2001-01-01

    Guangzhou is a city in southern China that has experienced very rapid economic development in recent years. The city's air has very high concentrations of various pollutants, including sulphur dioxide (SO 2 , oxides of nitrogen (NOx), ozone (O 3 ) and particulate. This paper reviews the changes in air quality in the city over the past 15 years, and notes that a serious vehicular-related emissions problem has been superimposed on the traditional coal-burning problem evident in most Chinese cities. As NOx concentrations have increased, oxidants and photochemical smog now interact with the traditional SO 2 and particulate pollutants, leading to increased health risks and other environmental concerns. Any responsible NOx control strategy for the city must include vehicle emission control measures. This paper reviews control strategies designed to abate vehicle emissions to fulfill the city's air quality improvement target in 2010. A cost-effectiveness analysis suggests that, while NOx emission control is expensive, vehicular emission standards could achieve a relatively sizable emissions reduction at reasonable cost. To achieve the 2010 air quality target of NOx, advanced implementation of EURO3 standards is recommended, substituting for the EURO2 currently envisioned in the national regulations Related technical options, including fuel quality improvements and inspection/maintenance (I/M) upgrades (ASM or IM240) are assessed as well. (author)

  9. Strategies for the plasma position and shape control in IGNITOR

    International Nuclear Information System (INIS)

    Villone, F.; Albanese, R.; Ambrosino, G.; Pironti, A.; Rubinacci, G.; Ramogida, G.; Alladio, F.; Bombarda, F.; Coletti, A.; Cucchiaro, A.; Maddaluno, G.; Pizzicaroli, G.; Pizzuto, A.; Roccella, M.; Santinelli, M.; Coppi, B.

    2007-01-01

    The capability of the poloidal field coil system, as presently designed, to provide an effective vertical stabilization of the plasma in the IGNITOR machine has been investigated using the CREATE L response model. An optimization of the vertical position control strategy has been carried out and the most effective coil combination has been selected to stabilize the plasma while fulfilling engineering constraints on the coils and minimizing the required power and voltage. The growth rate of the vertical instability and the power required by the active stabilization system has been estimated with this model. The possible failure of the relevant electromagnetic diagnostics has been taken into account, evaluating the robustness of the plasma position reconstruction strategy. A realistic description of the power supply system has permitted to carry out the optimization of the proportional-integrative-derivative (PID) controller, both with a voltage and a current loop control scheme. An assessment of the requirements for the plasma cross section shape control has been carried out considering perturbations of the plasma global parameters independent of each other and showing that the undesired shape modification rejection is possible with the present PFC and power supply system. The PF coils have been rated relative to their capability to restore shape modifications due to different plasma disturbances. The most effective coil combination, that minimizes recovery time and voltage required, has been identified

  10. Energy Optimal Control Strategy of PHEV Based on PMP Algorithm

    Directory of Open Access Journals (Sweden)

    Tiezhou Wu

    2017-01-01

    Full Text Available Under the global voice of “energy saving” and the current boom in the development of energy storage technology at home and abroad, energy optimal control of the whole hybrid electric vehicle power system, as one of the core technologies of electric vehicles, is bound to become a hot target of “clean energy” vehicle development and research. This paper considers the constraints to the performance of energy storage system in Parallel Hybrid Electric Vehicle (PHEV, from which lithium-ion battery frequently charges/discharges, PHEV largely consumes energy of fuel, and their are difficulty in energy recovery and other issues in a single cycle; the research uses lithium-ion battery combined with super-capacitor (SC, which is hybrid energy storage system (Li-SC HESS, working together with internal combustion engine (ICE to drive PHEV. Combined with PSO-PI controller and Li-SC HESS internal power limited management approach, the research proposes the PHEV energy optimal control strategy. It is based on revised Pontryagin’s minimum principle (PMP algorithm, which establishes the PHEV vehicle simulation model through ADVISOR software and verifies the effectiveness and feasibility. Finally, the results show that the energy optimization control strategy can improve the instantaneity of tracking PHEV minimum fuel consumption track, implement energy saving, and prolong the life of lithium-ion batteries and thereby can improve hybrid energy storage system performance.

  11. Current developments in bovine mastitis treatment and control.

    Science.gov (United States)

    Wager, L A; Linquist, W E; Hayes, G L; Britten, A M; Whitehead, R G; Webster, D E; Barnes, F D

    1978-01-01

    Mastitis in its complexity has managed to forestall all efforts of eradication in spite of years of research, antibiotics and practical control measures. This minisymposium will touch on seven topics current to treatment and control of this economically important disease.

  12. Strategies to control odours in livestock facilities: a critical review

    Directory of Open Access Journals (Sweden)

    Y. Ubeda

    2013-11-01

    Full Text Available Odours generated in livestock buildings constitute one of the most relevant air quality issues of intensive livestock production. Reducing nuisance episodes related to odour exposure is therefore essential for a sustainable livestock production. In this study, the state-of-the-art on odour mitigation techniques in livestock housing is critically reviewed. Scientific advances in the last decade are revised and research needs are also identified. The complex nature of livestock odours is firstly reviewed and examined. Then, the most relevant odour control strategies are analyzed in terms of present knowledge and future needs. The strategies considered are: nutritional strategies, manure additives, building design, air filtration, manure covers, manure treatment systems and windbreaks. Finally, future research needs and priorities when establishing mitigation techniques are identified. Despite important recent advances, there are still some challenges for scientists, producers and regulators, particularly related to field evaluation of odours. Therefore, to control livestock odours effectively, using standardized field assessment techniques will be required. Also, investigating measurement and model errors may be useful to better understand the limitations of the current methods, as well as to identify research priorities.

  13. Managing work and family: Do control strategies help?

    Science.gov (United States)

    Versey, H Shellae

    2015-11-01

    How can we effectively manage competing obligations from work and family without becoming overwhelmed? This question inspires the current study by examining control strategies that may facilitate better work-life balance, with a specific focus on the role of lowered aspirations and positive reappraisals, attitudes that underlie adaptive coping behaviors. Data from the Midlife in the United States Survey (MIDUS II) were used to explore the relationship between negative spillover, control strategies, and well-being among full-time working men and women (N = 2,091). In this nationally representative sample, findings indicate that while positive reappraisals function as a protective buffer, lowering aspirations exacerbate the relationship between work-family spillover and well-being, with moderating effects stronger among women. This study extends prior research tying work-life conflict to health and mental health, and suggests further investigation is needed to consider types of resources that may be effective coping strategies in balancing work and family. (c) 2015 APA, all rights reserved).

  14. The Robust Control Mixer Method for Reconfigurable Control Design By Using Model Matching Strategy

    DEFF Research Database (Denmark)

    Yang, Z.; Blanke, Mogens; Verhagen, M.

    2001-01-01

    This paper proposes a robust reconfigurable control synthesis method based on the combination of the control mixer method and robust H1 con- trol techniques through the model-matching strategy. The control mixer modules are extended from the conventional matrix-form into the LTI sys- tem form....... By regarding the nominal control system as the desired model, an augmented control system is constructed through the model-matching formulation, such that the current robust control techniques can be usedto synthesize these dynamical modules. One extension of this method with respect to the performance...... recovery besides the functionality recovery is also discussed under this framework. Comparing with the conventional control mixer method, the proposed method considers the recon gured system's stability, performance and robustness simultaneously. Finally, the proposed method is illustrated by a case study...

  15. Equivalence of Primary Control Strategies for AC and DC Microgrids

    Directory of Open Access Journals (Sweden)

    Eneko Unamuno

    2017-01-01

    Full Text Available Microgrid frequency and voltage regulation is a challenging task, as classical generators with rotational inertia are usually replaced by converter-interfaced systems that inherently do not provide any inertial response. The aim of this paper is to analyse and compare autonomous primary control techniques for alternating current (AC and direct current (DC microgrids that improve this transient behaviour. In this context, a virtual synchronous machine (VSM technique is investigated for AC microgrids, and its behaviour for different values of emulated inertia and droop slopes is tested. Regarding DC microgrids, a virtual-impedance-based algorithm inspired by the operation concept of VSMs is proposed. The results demonstrate that the proposed strategy can be configured to have an analogous behaviour to VSM techniques by varying the control parameters of the integrated virtual-impedances. This means that the steady-state and transient behaviour of converters employing these strategies can be configured independently. As shown in the simulations, this is an interesting feature that could be, for instance, employed for the integration of different dynamic generation or storage systems, such as batteries or supercapacitors.

  16. 40 CFR 52.1982 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1982... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Oregon § 52.1982 Control strategy... emission control equipment, selected from a specific list on file at DEQ, is in place and operating...

  17. A Decentralized Current-Sharing Controller Endows Fast Transient Response to Parallel DC-DC Converters

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Han, Renke

    2018-01-01

    This paper proposes a decentralized current-sharing control strategy to endow fast transient response to paralleled DC-DC converters systems, such as DC microgrids or distributed power systems. The proposed controller consist of two main control loops: an external voltage droop control for current......-sharing proposes and an internal current loop. The external droop control loop is designed as a voltage loop with embedded virtual impedance, which avoids the use of a slow voltage loop and a separate extra virtual impedance loop that may limit the system bandwidth. The internal current loop, thanks...... and the proposed embedded-virtual-impedance based I-V droop. In order to compare the dynamic response performances between two droop controllers, their state-space models have been developed and analyzed in this paper. The results show that the dynamic response of the I-V droop control is faster than...

  18. Current control loop of 3-phase grid-connected inverter

    International Nuclear Information System (INIS)

    Jabbar, A F; Mansor, M

    2013-01-01

    This paper presents a comparative study of current control loop in 3-phase inverter which is used to control the active and reactive output power. Generally, current control loop, power control loop and phase lock-loop are the conventional parameters that can be found in an inverter system controlled by the conventional linear control type, for instance proportional (P), integral (I) and derivative (D). If the grid remains stable throughout the day, PID control can be use. However variation of magnitude, frequency, voltage dips, transient, and other related power quality issues occur in a 3-phase grid often affects the control loop. This paper aims to provide an overall review on the available current control techniques used in grid connected system.

  19. Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

    Science.gov (United States)

    Hassaine, L.; Mraoui, A.

    2017-02-01

    Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

  20. Control of trachoma in Australia: a model based evaluation of current interventions.

    Directory of Open Access Journals (Sweden)

    Andrew J Shattock

    2015-04-01

    Full Text Available Australia is the only high-income country in which endemic trachoma persists. In response, the Australian Government has recently invested heavily towards the nationwide control of the disease.A novel simulation model was developed to reflect the trachoma epidemic in Australian Aboriginal communities. The model, which incorporates demographic, migration, mixing, and biological heterogeneities, was used to evaluate recent intervention measures against counterfactual past scenarios, and also to assess the potential impact of a series of hypothesized future intervention measures relative to the current national strategy and intensity. The model simulations indicate that, under the current intervention strategy and intensity, the likelihood of controlling trachoma to less than 5% prevalence among 5-9 year-old children in hyperendemic communities by 2020 is 31% (19%-43%. By shifting intervention priorities such that large increases in the facial cleanliness of children are observed, this likelihood of controlling trachoma in hyperendemic communities is increased to 64% (53%-76%. The most effective intervention strategy incorporated large-scale antibiotic distribution programs whilst attaining ambitious yet feasible screening, treatment, facial cleanliness and housing construction targets. Accordingly, the estimated likelihood of controlling trachoma in these communities is increased to 86% (76%-95%.Maintaining the current intervention strategy and intensity is unlikely to be sufficient to control trachoma across Australia by 2020. However, by shifting the intervention strategy and increasing intensity, the likelihood of controlling trachoma nationwide can be significantly increased.

  1. Control of trachoma in Australia: a model based evaluation of current interventions.

    Science.gov (United States)

    Shattock, Andrew J; Gambhir, Manoj; Taylor, Hugh R; Cowling, Carleigh S; Kaldor, John M; Wilson, David P

    2015-04-01

    Australia is the only high-income country in which endemic trachoma persists. In response, the Australian Government has recently invested heavily towards the nationwide control of the disease. A novel simulation model was developed to reflect the trachoma epidemic in Australian Aboriginal communities. The model, which incorporates demographic, migration, mixing, and biological heterogeneities, was used to evaluate recent intervention measures against counterfactual past scenarios, and also to assess the potential impact of a series of hypothesized future intervention measures relative to the current national strategy and intensity. The model simulations indicate that, under the current intervention strategy and intensity, the likelihood of controlling trachoma to less than 5% prevalence among 5-9 year-old children in hyperendemic communities by 2020 is 31% (19%-43%). By shifting intervention priorities such that large increases in the facial cleanliness of children are observed, this likelihood of controlling trachoma in hyperendemic communities is increased to 64% (53%-76%). The most effective intervention strategy incorporated large-scale antibiotic distribution programs whilst attaining ambitious yet feasible screening, treatment, facial cleanliness and housing construction targets. Accordingly, the estimated likelihood of controlling trachoma in these communities is increased to 86% (76%-95%). Maintaining the current intervention strategy and intensity is unlikely to be sufficient to control trachoma across Australia by 2020. However, by shifting the intervention strategy and increasing intensity, the likelihood of controlling trachoma nationwide can be significantly increased.

  2. Zener diode controls switching of large direct currents

    Science.gov (United States)

    1965-01-01

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

  3. Current Control of Grid Converters Connected with Series AC Capacitor

    DEFF Research Database (Denmark)

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

    2015-01-01

    The series ac capacitor has recently been used with the transformerless grid-connected converters in the distribution power grids. The capacitive characteristic of the resulting series LC filter restricts the use of conventional synchronous integral or stationary resonant current controllers. Thus...... this paper proposes a fourth-order resonant controller in the stationary frame, which guarantees a zero steady-state current tracking error for the grid converters with series LC filter. This method is then implemented in a three-phase experimental system for verification, where the current harmonics below...... the LC filter resonance frequency are effectively eliminated. Experimental results confirm the validity of the proposed current control scheme....

  4. Bowel Retraining: Strategies for Establishing Bowel Control

    Science.gov (United States)

    ... helpful, please consider supporting IFFGD with a small tax-deductible donation. Adapted from IFFGD Publication: Strategies for ... arises requiring an expert’s care. © Copyright 1998-2018 International Foundation for Functional Gastrointestinal Disorders, Inc. (IFFGD). All ...

  5. International Narcotics Control Strategy Report, 1997

    National Research Council Canada - National Science Library

    1998-01-01

    .... Continued warfare, destmction of the economic infrastmcture and absence of a recognized central government with administrative control over the entire country remain obstacles to effective dmg control...

  6. New strategy for eliminating zero-sequence circulating current between parallel operating three-level NPC voltage source inverters

    DEFF Research Database (Denmark)

    Li, Kai; Dong, Zhenhua; Wang, Xiaodong

    2018-01-01

    A novel strategy based on a zero common mode voltage pulse-width modulation (ZCMV-PWM) technique and zero-sequence circulating current (ZSCC) feedback control is proposed in this study to eliminate ZSCCs between three-level neutral point clamped (NPC) voltage source inverters, with common AC and DC......, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can...

  7. Simplified current minimization control of vector controlled Interior ...

    Indian Academy of Sciences (India)

    Thakur Sumeet Singh

    2018-04-12

    Apr 12, 2018 ... looked into loss-minimization control of PM motors by use of polynomial .... the chosen motor (''Appendix'') falls outside of its range. Figure 1. ..... command, mmf balance along q-axis should be maintained: (Lq being ...

  8. Beam physics design strategy for a high-current rf linac

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, M. [Univ. of Maryland, College Park, MD (United States)

    1995-10-01

    The high average beam power of an rf linac system for transmutation of nuclear waste puts very stringent requirements on beam quality and beam control. Fractional beam losses along the accelerator must be kept at extremely low levels to assure {open_quotes}hands-on{close_quotes} maintenance. Hence, halo formation and large-amplitude tails in the particle distribution due to beam mismatch and equipartitioning effects must be avoided. This implies that the beam should ideally be in near-perfect thermal equilibrium from injection to full energy - in contrast to existing rf linacs in which the transverse temperature, T {sub {perpendicular}}, is higher than the longitudinal temperature, T{sub {parallel}}. The physics and parameter scaling for such a system will be reviewed using the results of recent work on high-intensity bunched beams. A design strategy for a high-current rf linac with equilibrated beam will be proposed.

  9. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...

  10. Coordination of Project and Current Activities on the Basis of the Strategy Alignment Metamodel in the Oil and Gas Company

    Directory of Open Access Journals (Sweden)

    R. Yu. Dashkov

    2017-01-01

    Full Text Available Purpose: the purpose of this article is to describe the Strategy Alignment Metamodel of the project and current activities, which allows us to connect the Goals and Strategies for Phases of the project with the Goals and Strategies of the company at all levels of the organization through targeted measurement and application of Interpretive Models. Building Networks of Goals and Strategies, and adopting organizational solutions, you coordinate the interaction of the Project office and departments of the company. This methodology is based on a Logical Rationale of the Contexts and Assumptions for establishing Goals and Strategies both for the project and for the company, and on preparation of Contexts and Assumptions, Goals and Strategies Alignment Matrices, which provides a flexible adaptation to the internal and external environment in the process of selecting the most successful Strategies to achieve the Goals. Methods: this article is based on the concept of Goals-Questions-Metrics+ Strategies, which is adapted as another concept of strategic monitoring and control system of projects: Goals-Phases-Metrics+Strategies. These concepts have formed the basis of the Strategy Alignment Metamodel, where a technology of Phases Earned Value Management is used as a measurement system for the project activity, and Balanced scorecard is applied for current operations. Results: strategy Alignment Metamodel of the project and current activities of the company is proposed hereby. It uses modern strategic monitoring and control systems for projects: Goals-Phases-Metrics+Strategies, and for the company: Goals-Questions-Metrics+ Strategies. The interaction between these systems is based on Contexts and Assumptions, Goals and Strategies Alignment Matrices. The existence of such matrices greatly simplifies management decisions and prevents the risk of delays in the execution of project Phases based on rational participation and coordination of the company

  11. A control strategy for PV stand-alone applications

    Science.gov (United States)

    Slouma, S.; Baccar, H.

    2015-04-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system.

  12. A control strategy for PV stand-alone applications

    International Nuclear Information System (INIS)

    Slouma, S; Baccar, H

    2015-01-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system

  13. Control Strategies for Arrays of Wave Energy Devices

    OpenAIRE

    Westphalen, J; Bacelli, G; Balitsky, P; Ringwood, John

    2011-01-01

    In this paper, we investigate the differences between two control strategies for a two-device linear array of wave energy converters (WEC) for device spacings of 4 to 80 times the device diameter. The WECs operate in heave only and are controlled in real time. The control strategies, called the independent device and global array control, estimate the excitation forces and calculate the optimum vertical velocity trajectory and reactive power take off force to achieve the ...

  14. Comparison among nonlinear excitation control strategies used for damping power system oscillations

    International Nuclear Information System (INIS)

    Leon, A.E.; Solsona, J.A.; Valla, M.I.

    2012-01-01

    Highlights: ► A description and comparison of nonlinear control strategies for synchronous generators are presented. ► Advantages of using nonlinear controllers are emphasized against the use of classical PSSs. ► We find that a particular selection of IDA gains achieve the same performance that FL controllers. - Abstract: This work is focused on the problem of power system stability. A thorough description of nonlinear control strategies for synchronous generator excitation, which are designed for damping oscillations and improving transient stability on power systems, is presented along with a detailed comparison among these modern strategies and current solutions based on power system stabilizers. The performance related to damping injection in each controller, critical time enhancement, robustness against parametric uncertainties, and control signal energy consumption is analyzed. Several tests are presented to validate discussions on various advantages and disadvantages of each control strategy.

  15. Design and implementation of predictive current control of three-phase PWM rectifier using space-vector modulation (SVM)

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Gaubert, Jean-Paul; Krim, Fateh

    2010-01-01

    This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α-β and rotating d-q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.

  16. New control strategies for neuroprosthetic systems

    NARCIS (Netherlands)

    Crago, Patrick E.; Veltink, Petrus H.; Lan, Ning; Abbas, James J.; Kantor, Carole

    1996-01-01

    The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to

  17. 40 CFR 52.1582 - Control strategy and regulations: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... Control strategy and regulations: Ozone. (a) Subchapter 16 of the New Jersey Administrative Code, entitled... demonstration that emissions from growth in vehicle miles traveled will not increase motor vehicle emissions and...

  18. 40 CFR 52.724 - Control strategy: Sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Sulfur dioxide. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.724 Control strategy: Sulfur... Energy Incorporated. This disapproval does not in and of itself result in the growth restrictions of...

  19. 40 CFR 52.2332 - Control Strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control Strategy: Ozone. 52.2332 Section 52.2332 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Utah § 52.2332 Control Strategy...

  20. 40 CFR 52.377 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.377 Section 52.377 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.377 Control strategy: Ozone. (a...

  1. 40 CFR 52.1885 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1885 Section 52.1885 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Ohio § 52.1885 Control strategy...

  2. 40 CFR 52.378 - Control strategy: PM10

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: PM10 52.378 Section 52.378 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.378 Control strategy: PM10 (a) Approval...

  3. 40 CFR 52.1023 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1023 Section 52.1023 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Maine § 52.1023 Control strategy...

  4. 40 CFR 52.66 - Control Strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control Strategy: Ozone. 52.66 Section 52.66 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.66 Control Strategy: Ozone. (a) The...

  5. 40 CFR 52.582 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.582 Section 52.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Georgia> § 52.582 Control strategy: Ozone. (a) Approval...

  6. 40 CFR 52.930 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.930 Section 52.930 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.930 Control strategy: Ozone. (a) The VOC...

  7. 40 CFR 52.350 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.350 Section 52.350 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions...

  8. 40 CFR 52.476 - Control strategy: ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: ozone. 52.476 Section 52.476 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS District of Columbia § 52.476 Control strategy: ozone. (a...

  9. 40 CFR 52.2236 - Control strategy; lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy; lead. 52.2236 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2236 Control strategy; lead... on October 6, 1994. These revisions address the requirements necessary to change a lead nonattainment...

  10. 40 CFR 52.58 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Lead. 52.58 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.58 Control strategy: Lead. The lead plan... the lead standard throughout Alabama. The lead plan submitted by the State on October 7, 1985, and...

  11. 40 CFR 52.1375 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Lead. 52.1375 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Montana § 52.1375 Control strategy: Lead. Determination—EPA has determined that the East Helena Lead nonattainment area has attained the lead national...

  12. 40 CFR 52.1681 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Lead. 52.1681 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New York § 52.1681 Control strategy: Lead. As part of the attainment demonstration for lead, the State of New York has committed to rate all sources...

  13. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control Strategy: Nitrogen oxides. 52.65 Section 52.65 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen...

  14. Eddy current quality control of soldered current-carrying busbar splices of superconducting magnets

    CERN Document Server

    Kogan, L; Savary, F; Principe, R; Datskov, V; Rozenfel'd, E; Khudjakov, B

    2015-01-01

    The eddy current technique associated with a U-shaped transducer is studied for the quality control of soldered joints between superconducting busbars ('splices'). Two other quality control techniques, based on X-rays and direct measurement of the electrical resistance, are also studied for comparison. A comparative analysis of the advantages and disadvantages of these three methods in relation to the quality control of soldered superconducting busbar cables enclosed in copper shells is used for benchmarking. The results of inspections with the U-shaped eddy current transducer carried out on several sample joints presenting different types of soldering defects show the potential of this type of nondestructive (ND) quality control technique.

  15. Agent-based Cyber Control Strategy Design for Resilient Control Systems: Concepts, Architecture and Methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Craig Rieger; Milos Manic; Miles McQueen

    2012-08-01

    The implementation of automated regulatory control has been around since the middle of the last century through analog means. It has allowed engineers to operate the plant more consistently by focusing on overall operations and settings instead of individual monitoring of local instruments (inside and outside of a control room). A similar approach is proposed for cyber security, where current border-protection designs have been inherited from information technology developments that lack consideration of the high-reliability, high consequence nature of industrial control systems. Instead of an independent development, however, an integrated approach is taken to develop a holistic understanding of performance. This performance takes shape inside a multiagent design, which provides a notional context to model highly decentralized and complex industrial process control systems, the nervous system of critical infrastructure. The resulting strategy will provide a framework for researching solutions to security and unrecognized interdependency concerns with industrial control systems.

  16. Cerebellar transcranial direct current stimulation improves adaptive postural control.

    Science.gov (United States)

    Poortvliet, Peter; Hsieh, Billie; Cresswell, Andrew; Au, Jacky; Meinzer, Marcus

    2018-01-01

    Rehabilitation interventions contribute to recovery of impaired postural control, but it remains a priority to optimize their effectiveness. A promising strategy may involve transcranial direct current stimulation (tDCS) of brain areas involved in fine-tuning of motor adaptation. This study explored the effects of cerebellar tDCS (ctDCS) on postural recovery from disturbance by Achilles tendon vibration. Twenty-eight healthy volunteers participated in this sham-ctDCS controlled study. Standing blindfolded on a force platform, four trials were completed: 60 s quiet standing followed by 20 min active (anodal-tDCS, 1 mA, 20 min, N = 14) or sham-ctDCS (40 s, N = 14) tDCS; three quiet standing trials with 15 s of Achilles tendon vibration and 25 s of postural recovery. Postural steadiness was quantified as displacement, standard deviation and path derived from the center of pressure (COP). Baseline demographics and quiet standing postural steadiness, and backwards displacement during vibration were comparable between groups. However, active-tDCS significantly improved postural steadiness during vibration and reduced forward displacement and variability in COP derivatives during recovery. We demonstrate that ctDCS results in short-term improvement of postural adaptation in healthy individuals. Future studies need to investigate if multisession ctDCS combined with training or rehabilitation interventions can induce prolonged improvement of postural balance. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  17. Current control of superconducting coils for fusion experimental facility

    International Nuclear Information System (INIS)

    Ise, T.; Etou, D.; Chikaraishi, H.; Takami, S.; Inoue, T.

    2003-01-01

    The LHD (Large Helical Device) has twelve superconducting coils and six dc power supplies, and following specifications are required for its control system; each coil current must be controlled independently, the steady state control error is less than 0.01% of the reference value, the current settling time for 0.1% of control error is less than 1 second, and the control system must be robust against turbulence caused by appearance and disappearance of the plasma, parameter errors and external electro-magnetic noises. In this paper, the design and test results of the coil current control system for the LHD are described. The good response and robustness are in the relation of trade off each other. H-infinity controller is one of schemes to guarantee robustness for stability. However, the independent responses of six coils were impossible by the H-infinity controller only. To resolve this problem, we applied a feed-forward control with the H-infinity control. Moreover, the advanced design method of H-infinity controller using μ-synthesis was applied to guarantee the control performance in the whole operating condition. As a result, good control results were obtained by experiments. (author)

  18. Complex state variable- and disturbance observer-based current controllers for AC drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus; Blaabjerg, Frede

    2013-01-01

    In vector-controlled AC drives, the design of current controller is usually based on a machine model defined in synchronous frame coordinate, where the drive performance may be degraded by both the variation of the machine parameters and the cross-coupling between the d- and q-axes components...... of the stator current. In order to improve the current control performance an alternative current control strategy was proposed previously aiming to avoid the undesired cross-coupling and non-linearities between the state variables. These effects are assumed as disturbances arisen in the closed-loop path...... of the parameter and the cross-coupling effect. Moreover, it provides a better performance, smooth and low noisy operation with respect to the complex variable controller....

  19. Impact of VSC Control Strategies and Incorporation of Synchronous Condensers on Distance Protection under Unbalanced Faults

    DEFF Research Database (Denmark)

    Jia, Jundi; Yang, Guangya; Nielsen, Arne Hejde

    2018-01-01

    on distance protection are evaluated using a commercial relay through hardware-in-the-loop (HIL) tests. Based on the test results, we propose to avoid using constant reactive power control strategy. It poses an adverse impact on the reliability and speed of distance protection regardless of the presence of SC....... This might bring up challenges to the protection system of a converter-dominated power system. This paper derives a generic converter peak current limitation method for three different VSC control strategies. The impact of the control strategies and the combined impact of a VSC with a synchronous condenser...... at the point of common coupling (PCC), while constant active power and balanced current control strategies favor the performances of distance protection....

  20. Backstepping Strategy for Induction Motor Control

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2000-01-01

    Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping with a s......Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping...... with a simple flux observer is used in the design. Assuming known motor parameters the design achieves stability with guaranteed region of attraction. It is also shown how a conventional field oriented controller may be obtained by omitting parts of the nonlinear controller....

  1. Model Predictive Current Control for High-Power Grid-Connected Converters with Output LCL Filter

    DEFF Research Database (Denmark)

    Delpino, Hernan Anres Miranda; Teodorescu, Remus; Rodriguez, Pedro

    2009-01-01

    A model predictive control strategy for a highpower, grid connected 3-level neutral clamped point converter is presented. Power losses constraints set a limit on commutation losses so reduced switching frequency is required, thus producing low frequency current harmonics. To reduce these harmonics...

  2. LOW-INCOME, MINORITY FATHERS’ CONTROL STRATEGIES AND THEIR CHILDREN'S REGULATORY SKILLS

    OpenAIRE

    Malin, Jenessa L.; Cabrera, Natasha J.; Karberg, Elizabeth; Aldoney, Daniela; Rowe, Meredith Lee

    2014-01-01

    The current study explored the bidirectional association of children's individual characteristics, fathers' control strategies at 24-months and children's regulatory skills at pre-kindergarten (pre-K). Using a sample of low-income minority families with 2-year-olds from the Early Head Start Evaluation Research Program (n = 71) we assessed the association between child gender and vocabulary skills, fathers' control strategies at 24-months (e.g., regulatory behavior and regulatory language), an...

  3. A current controlled variable delay superconducting transmission line

    International Nuclear Information System (INIS)

    Anlage, S.M.; Snortland, H.J.; Beasley, M.R.

    1989-01-01

    The authors present a device concept for a current-controlled variable delay for superconducting transmission line. The device makes use of the change in kinetic inductance of a superconducting transmission line under the application of a DC bias current. The relevant materials parameters and several promising superconducting materials have been identified

  4. Current control by a homopolar machine with moving brushes

    International Nuclear Information System (INIS)

    Vogel, H.

    1978-01-01

    The equation for TNS Doublet's E-coil circuit with moving brush homopolar machine is integrated in the flux of the homopolar for a monotonically increasing current function extending beyond the current reversal into the burn period. The results show that the moving brush feature is not useful for controlling the burn

  5. Linguistic Gender Sensitivity Strategies in Current South African Intermediate Phase English Workbooks: Feminisation or Degenderisation?

    Science.gov (United States)

    Sibanda, Jabulani; Sibanda, Lucy

    2016-01-01

    This study extends research on manifestations of gender insensitivity in learners' reading materials by shifting attention to the linguistic strategies that authors of current texts employ for the realisation of gender sensitivity. We analysed the content of 12 current (2014) English workbooks (Grade 4-6) used in South African government and…

  6. Nitrate control strategies in an activated sludge wastewater treatment process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wenhao; Tao, Erpan; Chen, Xiaoquan; Liu, Dawei [South China University of Technology, Guangzhou (China); Liu, Hongbin [Kyung Hee University, Yongin (Korea, Republic of)

    2014-03-15

    We studied nitrate control strategies in an activated sludge wastewater treatment process (WWTP) based on the activated sludge model. Two control strategies, back propagation for proportional-integral-derivative (BP-PID) and adaptive-network based fuzzy inference systems (ANFIS), are applied in the WWTP. The simulation results show that the simple local constant setpoint control has poor control effects on the nitrate concentration control. However, the ANFIS (4*1) controller, which considers not only the local constant setpoint control of the nitrate concentration, but also three important indices in the effluent--ammonia concentration, total suspended sludge concentration and total nitrogen concentration--demonstrates good control performance. The results also prove that ANFIS (4*1) controller has better control performance than that of the controllers PI, BP-PID and ANFIS (2*1), and that the ANFIS (4*1) controller is effective in improving the effluent quality and maintaining the stability of the effluent quality.

  7. VOC from Vehicular Evaporation Emissions: Status and Control Strategy.

    Science.gov (United States)

    Liu, Huan; Man, Hanyang; Tschantz, Michael; Wu, Ye; He, Kebin; Hao, Jiming

    2015-12-15

    Vehicular evaporative emissions is an important source of volatile organic carbon (VOC), however, accurate estimation of emission amounts and scientific evaluation of control strategy for these emissions have been neglected outside of the United States. This study provides four kinds of basic emission factors: diurnal, hot soak, permeation, and refueling. Evaporative emissions from the Euro 4 vehicles (1.6 kg/year/car) are about four times those of U.S. vehicles (0.4 kg/year/car). Closing this emissions gap would have a larger impact than the progression from Euro 3 to Euro 6 tailpipe HC emission controls. Even in the first 24 h of parking, China's current reliance upon the European 24 h diurnal standard results in 508 g/vehicle/year emissions, higher than 32 g/vehicle/year from Tier 2 vehicles. The U.S. driving cycle matches Beijing real-world conditions much better on both typical trip length and average speed than current European driving cycles. At least two requirements should be added to the Chinese emissions standards: an onboard refueling vapor recovery to force the canister to be sized sufficiently large, and a 48-h evaporation test requirement to ensure that adequate purging occurs over a shorter drive sequence.

  8. Current control by ECCD for W7-X

    International Nuclear Information System (INIS)

    Turkin, Yu.; Maassberg, H.; Beidler, C.D.; Geiger, J.; Marushchenko, N.B.

    2005-01-01

    One of the optimization criteria for the stellarator W7-X is the minimization of the bootstrap current. The plasma current changes the magnetic configuration, especially near the plasma edge, where X-points and islands are located. It was shown that the plasma parameter distributions in the divertor region and the particle and energy depositions on the divertor plates depend strongly on the island geometry. An estimation of the tolerable plasma current obtained from the shift of the island structure close to the target plates shows that the plasma current should be controlled within a range of about 10 kA. The bootstrap current even for the standard configuration can easily exceed this value. The W7-X is not equipped with an Ohmic transformer, so the only means for compensating this current is electron cyclotron current drive (ECCD) and/or neutral beam current drive (NBCD). In this report we study the compensation of residual bootstrap current by using ECCD. To model the control of the toroidal current we use a predictive 1D transport code, which is under development. For evaluation of the bootstrap current and neoclassical transport coefficients we use results from an international collaboration on neoclassical transport in stellarators. Power deposition and current drive profiles due to electron cyclotron resonance heating are calculated by a new ray tracing code. The modeling showed that the loop voltage induced by ECCD leads to a redistribution of the current density with the diffusion time of about two seconds. The relaxation time of the total current is much longer than this time - for a typical ECRH-plasma the total toroidal current reaches steady state after several L/R-time that is about hundreds of seconds. In order to keep current in an acceptable range and to avoid long relaxation times we propose Feed-forward or Predictive control using ECCD as actuator, the steps are as follows: - calculate the bootstrap current distribution using measured plasma

  9. Strategies for the plasma position and shape control in IGNITOR

    International Nuclear Information System (INIS)

    Ramogida, G.; Alladio, F.; Albanese, R.

    2006-01-01

    The control of the plasma position and shape is a crucial issue in IGNITOR as in every compact, high field, elongated tokamak. The capability of the Poloidal Field Coil system, as presently designed, to provide an effective vertical stabilization of the plasma has been investigated using the CREATE L response model [R. Albanese, F. Villone, '' The Linearized CREATE L Plasma Response Model for the Control of Current, Position and Shape in Tokamaks '', Nucl. Fus., vol. 38, p. 723 (1998)]. This linearized MHD model assumes an axisymmetric deformable plasma described by few global parameters. An optimization of the vertical position control strategy has been carried out and the most effective coil combination has been selected to stabilize the plasma while fulfilling engineering constraints on the coils and minimizing the required power and voltage. The two pairs of coils selected for the vertical control will be fed up with up-down anti-symmetric currents provided by a dedicated supply and overlapped to the scenario currents. The growth rate of the vertical instability and the power required by the active stabilization system have been estimated with this model, indicating that it is possible to design a control system able to guarantee a stability region that includes the most interesting operation conditions. An assessment of the requirements for the plasma cross section shape control has been carried out considering independent perturbations of the plasma global parameters as disturbances and showing that the undesired shape modification rejection is possible with the present PFC and power supply system. The PF coils have been ranked with respect to their capability to restore the shape modifications due to different plasma disturbances and the most effective coil combination, that minimizes recovery time and voltage required, has been selected. In order to have additional means to monitor and control the centre of the plasma column, under demanding conditions

  10. Constant voltage and constant current control implementation for electric vehicles (evs) wireless charger

    Science.gov (United States)

    Tampubolon, Marojahan; Pamungkas, Laskar; Hsieh, Yao Ching; Chiu, Huang Jen

    2018-04-01

    This paper presents the implementation of Constant Voltage (CV) and Constant Current (CC) control for a wireless charger system. A battery charging system needs these control modes to ensure the safety of the battery and the effectiveness of the charging system. Here, the wireless charger system does not employ any post-regulator stage to control the output voltage and output current of the charger. But, it uses a variable frequency control incorporated with a conventional PI control. As a result, the size and the weight of the system are reduced. This paper discusses the brief review of the SS-WPT, control strategy and implementation of the CV and CC control. Experimental hardware with 2kW output power has been performed and tested. The results show that the proposed CV and CC control method works well with the system.

  11. A DC-Link Modulation Scheme with Phase-Shifted Current Control for Harmonic Cancellations in Multidrive Applications

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2016-01-01

    of a new DC link modulation scheme with a phase-shifted current control enabled by the SCR. The DC-link current modulation scheme is implemented by adding and subtracting specific modulation levels, which makes the total currents drawn from the grid “multi-level”, resulting in an improved current quality......This letter proposes a harmonic mitigation strategy to cancel out current harmonics induced by the front-end rectifiers in multi-drive systems, which consist of diode rectifiers, Silicon-Controlled Rectifiers (SCR), and boost converters in the DC-link. The proposed strategy is a combination...

  12. Compressor Load Stand: Commissioning and Control Strategies

    National Research Council Canada - National Science Library

    Causey, Andrew

    1998-01-01

    .... The purpose of this research project was to commission this load stand, which includes setting up the hardware, setting up a control system, a data acquisition system, and an automatic test sequence system...

  13. Fusion instrumentation and control: a development strategy

    International Nuclear Information System (INIS)

    Hsu, P.Y.; Greninger, R.C.; Longhurst, G.R.; Madden, P.

    1981-01-01

    We have examined requirements for a fusion instrumentation and control development program to determine where emphasis is needed. The complex, fast, and closely coupled system dynamics of fusion reactors reveal a need for a rigorous approach to the development of instrumentation and control systems. A framework for such a development program should concentrate on three principal need areas: the operator-machine interface, the data and control system architecture, and fusion compatible instruments and sensors. System dynamics characterization of the whole fusion reactor system is also needed to facilitate the implementation process in each of these areas. Finally, the future need to make the instrumentation and control system compatible with the requirements of a commercial plant is met by applying transition technology. These needs form the basis for the program tasks suggested

  14. Construction machine control guidance implementation strategy.

    Science.gov (United States)

    2010-07-01

    Machine Controlled Guidance (MCG) technology may be used in roadway and bridge construction to improve construction efficiencies, potentially resulting in reduced project costs and accelerated schedules. The technology utilizes a Global Positioning S...

  15. Strategies to control vehicular emissions: Indian scenario

    Energy Technology Data Exchange (ETDEWEB)

    Virupaksha, T. [Central Institute of Road Transport, Pune (India)

    2002-07-01

    The paper presents a common urban transport policy framework to protect the local and global environment and a state-of-the-art review of recommendations and measures suggested by the local administration in Indian cities from time to time. The measures to combat pollution in urban areas is identified by different cities but there is no cohesive strategy for implementing them. The pursuit of some of these measures are that the haphazard and piecemeal measures have not helped to gain optimum benefit possible or to make a discernible impact on mobility demand and vehicular emissions. A more practical strategy is required to reduce both emission and congestion, using a mixed set of instruments. The instruments are taxes on fuels, vehicles, and parking, incentives and regulations affecting vehicle ownership, usage and movement, traffic management more importantly encouraging non-motorized transport like bicycles by providing suitable lanes. Some of the policy measures seriously needed to be implemented to reduce ongoing pollution menace are enforcing higher maintenance standards, introducing vehicles designed to meet stricter emission standards, retrofitting vehicles to use other kinds of clean fuel, reducing urban congestion through transport management measures, scrapping highly polluting and high usage vehicles, and strengthening institutional links and regulatory issues. 5 refs., 1 tab.

  16. Control Strategies for Guided Collective Motion

    Science.gov (United States)

    2015-02-27

    J.K. Parrish , “Oscillator models and collective motion,” IEEE Control Systems Magzine, Vol. 27, 2007, pp. 89-105. [18] S. H. Strogatz , “From Kuramoto...Automatic Control, 54(2), 2009, pp. 353-357. [21] H. Hong and S. H. Strogatz , “Kuramoto Model of Coupled Oscillators with Positive and Negative...2013) provided similar results by utilizing a modified Kuramoto model ( Strogatz (2000)). Paley (2008) proposed a Lyapunov-based design methodology to

  17. High Precision Current Control for the LHC Main Power Converters

    CERN Document Server

    Thiesen, H; Hudson, G; King, Q; Montabonnet, V; Nisbet, D; Page, S

    2010-01-01

    Since restarting at the end of 2009, the LHC has reached a new energy record in March 2010 with the two 3.5 TeV beams. To achieve the performance required for the good functioning of the accelerator, the currents in the main circuits (Main Bends and Main Quadrupoles) must be controlled with a higher precision than ever previously requested for a particle accelerator at CERN: a few parts per million (ppm) of nominal current. This paper describes the different challenges that were overcome to achieve the required precision for the current control of the main circuits. Precision tests performed during the hardware commissioning of the LHC illustrate this paper.

  18. Strategies for controlling acid rain: economic considerations

    International Nuclear Information System (INIS)

    Forster, B.A.; Crocker, T.D.

    1992-01-01

    There are two competing approaches to reducing pollution such as the acid rain precursors SOsub(2) and NOsub(x). In the command and control approach, pollution control legislation may dictate the technological method by which specified pollution reductions are to be achieved. A key feature of command-and-control regulations is their inflexibility. The alternative approach relies on market mechanisms and incentives to induce firms to reduce pollution voluntarily. Economists generally prefer this approach because it permits flexibility for firms in selecting abatement methods to minimize costs. This chapter deals with qualitative issues in determining and achieving an ''optimal'' pollution level using various taxes, subsidies or quantitative restrictions. Alternative permit schemes for achieving regional pollution control are considered. Statistical studies are discussed which compare the command-and-control approach with the economic incentives approach and show that there are substantial cost differences between them in most cases. Finally, some institutional factors, that may lead to more costly acid rain control schemes being selected, are examined. A list of 61 references is appended. (UK)

  19. Evaluating the combined effectiveness of influenza control strategies and human preventive behavior.

    Directory of Open Access Journals (Sweden)

    Liang Mao

    Full Text Available Control strategies enforced by health agencies are a major type of practice to contain influenza outbreaks. Another type of practice is the voluntary preventive behavior of individuals, such as receiving vaccination, taking antiviral drugs, and wearing face masks. These two types of practices take effects concurrently in influenza containment, but little attention has been paid to their combined effectiveness. This article estimates this combined effectiveness using established simulation models in the urbanized area of Buffalo, NY, USA. Three control strategies are investigated, including: Targeted Antiviral Prophylaxis (TAP, workplace/school closure, community travel restriction, as well as the combination of the three. All control strategies are simulated with and without regard to individual preventive behavior, and the resulting effectiveness are compared. The simulation outcomes suggest that weaker control strategies could suffice to contain influenza epidemics, because individuals voluntarily adopt preventive behavior, rendering these weaker strategies more effective than would otherwise have been expected. The preventive behavior of individuals could save medical resources for control strategies and avoid unnecessary socio-economic interruptions. This research adds a human behavioral dimension into the simulation of control strategies and offers new insights into disease containment. Health policy makers are recommended to review current control strategies and comprehend preventive behavior patterns of local populations before making decisions on influenza containment.

  20. Improved control strategy for the three-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Yao, Zhilei; Xiao, Lan; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d- and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer....... As the reference output voltage cannot directly reflect the change of the reference grid current, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d- and q-axis grid currents in the decoupled components of the grid current controller can be substituted...... by the d- and q-axis reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results for a 15-kVA three-phase grid-connected inverter with SVPWM verify the theoretical analysis. Compared with the traditional control...

  1. A GPS-Based Control Framework for Accurate Current Sharing and Power Quality Improvement in Microgrids

    DEFF Research Database (Denmark)

    Golsorkhi, Mohammad; Savaghebi, Mehdi; Lu, Dylan

    2017-01-01

    This paper proposes a novel hierarchical control strategy for improvement of load sharing and power quality in ac microgrids. This control framework is composed of a droop based controller at the primary level, and a combination of distributed power sharing and voltage conditioning schemes...... consensus protocol to ensure proportional sharing of average power. The voltage conditioning scheme produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method....... dynamic response. The droop coefficient, which acts as a virtual resistance is adaptively changed as a function of the peak current. This strategy not only simplifies the control design but also improves the current sharing accuracy at high loading conditions. The distributed power sharing scheme uses...

  2. Control strategies for friction dampers: numerical assessment and experimental investigations.

    Directory of Open Access Journals (Sweden)

    Coelho H.T.

    2014-01-01

    Full Text Available The use of friction dampers has been proposed in a wide variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes. In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the dampers. The aim of this paper is to study three control strategies for friction dampers based on the hysteresis cycle. The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak. The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices. Finally, is presented the strategy which homogenously modulates the friction force. Numerical studies were performed with these three strategies defining the performance metrics. The best control strategy was applied experimentally. The experimental test rig was fully identified and its parameters were used for the numerical simulations. The obtained results show the good performance for the friction damper and the selected strategy.

  3. 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.

  4. 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

  5. FACTS device control strategy using PMU

    Directory of Open Access Journals (Sweden)

    Mohd Tauseef Khan

    2016-09-01

    Full Text Available The laying and commissioning of new transmission line is very difficult due to socio-economic problems, like environmental clearances, right of way, etc. Therefore, there is an emphasis on better utilization of available transmission infrastructure. FACTS devices can provide reactive power compensation, transmission capability enhancement, and voltage and stability improvement. FACTS devices operate under the command of system operator who analyses its demand by the data acquired through traditional SCADA system, state estimation algorithms and PMUs. SCADA together with PMU give accurate information about the operational state of power system. This paper proposes a scheme to automate the FACTS devices in collaboration with PMUs in a more efficient way. Highly precised data from PMUs can be fed to intelligent controllers for effective analyzing and automating the FACTS device through control command. Thus, this combination can provide real time control of reactive power, together with enhancement of power handling capability and stability improvement.

  6. Control Plane Strategies for Elastic Optical Networks

    DEFF Research Database (Denmark)

    Turus, Ioan

    Networks (EONs) concept is proposed as a solution to enable a more flexible handling of the optical capacity and allows an increase of available capacity over the existing optical infrastructure. One main requirement for enabling EONs is to have a flexible spectrum structure (i.e.Flex-Grid) which allows...... the spectrum to be used as an on-demand resource. Flex-Grid raises new challenges for controlling the dynamic spectrum slots environment. This thesis addresses, as part of the Celtic project “Elastic Optical Networks” (EONet), the control of Flex-Grid architectures by extending the capabilities of a GMPLS...... (Generalized Multi-Protocol Label Switching)-based control framework in accordance with existing IETF standards and recommendations. The usual approach of extending capacity in transport networks by incrementally adding more optical resources results in a very inefficient usage and determines a high power...

  7. Advanced control strategies for a drill rig

    International Nuclear Information System (INIS)

    Banerjee, A.; Hiller, M.; Fink, B.

    1996-01-01

    The construction of tunnels is usually undertaken using a combination of blasting and drilling to achieve rock excavation. Easy handling and high accuracy, and thus greater efficiency, in drilling rigs is an essential ingredient of successful competition in the market place. This article describes a cartesian control concept used for a twin boom drill rig. This simplifies the handling of a drilling boom, reduces the duration of a working cycle and increases security. A remote control system has been added to the drill rig to support the operator working in complicated environments. (UK)

  8. Efficient community-based control strategies in adaptive networks

    International Nuclear Information System (INIS)

    Yang Hui; Tang Ming; Zhang Haifeng

    2012-01-01

    Most studies on adaptive networks concentrate on the properties of steady state, but neglect transient dynamics. In this study, we pay attention to the emergence of community structure in the transient process and the effects of community-based control strategies on epidemic spreading. First, by normalizing the modularity, we investigate the evolution of community structure during the transient process, and find that a strong community structure is induced by the rewiring mechanism in the early stage of epidemic dynamics, which, remarkably, delays the outbreak of disease. We then study the effects of control strategies started at different stages on the prevalence. Both immunization and quarantine strategies indicate that it is not ‘the earlier, the better’ for the implementation of control measures. And the optimal control effect is obtained if control measures can be efficiently implemented in the period of a strong community structure. For the immunization strategy, immunizing the susceptible nodes on susceptible–infected links and immunizing susceptible nodes randomly have similar control effects. However, for the quarantine strategy, quarantining the infected nodes on susceptible–infected links can yield a far better result than quarantining infected nodes randomly. More significantly, the community-based quarantine strategy performs better than the community-based immunization strategy. This study may shed new light on the forecast and the prevention of epidemics among humans. (paper)

  9. Evaluation of Current Controllers for Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Timbus, Adrian; Liserre, Marco; Teodorescu, Remus

    2009-01-01

    This paper discusses the evaluation of different current controllers employed for grid-connected distributed power generation systems having variable input power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional-integral, proportio......This paper discusses the evaluation of different current controllers employed for grid-connected distributed power generation systems having variable input power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional......-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation is also presented. Since the paper discusses the implementation of these controllers for grid-connected applications, their evaluation is made in three operating conditions....... First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input power variations and grid voltage faults is also examined. Experimental results...

  10. A new inertia weight control strategy for particle swarm optimization

    Science.gov (United States)

    Zhu, Xianming; Wang, Hongbo

    2018-04-01

    Particle Swarm Optimization is a member of swarm intelligence algorithms, which is inspired by the behavior of bird flocks. The inertia weight, one of the most important parameters of PSO, is crucial for PSO, for it balances the performance of exploration and exploitation of the algorithm. This paper proposes a new inertia weight control strategy and PSO with this new strategy is tested by four benchmark functions. The results shows that the new strategy provides the PSO with better performance.

  11. On Control Strategies for Responsive Architectural Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Parigi, Dario

    2012-01-01

    The present paper considers control of responsive architectural structures for improvement of structural performance by recognizing changes in their environments and loads, adapting to meet goals, and using past events to improve future performance or maintain serviceability. The general scope of...

  12. Locus of control and learning strategies as predictors of academic ...

    African Journals Online (AJOL)

    The aim of the research was to determine the relationships which exist between academic success, learning strategies and locus of control. In order to achieve this aim a small-scale quantitative study, utilising two inventories, was done. The first measuring instrument is the Learning and Study Strategies Inventory, which is ...

  13. 40 CFR 52.2585 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2585... strategy: Ozone. (a) Disapproval—On November 6, 1986, the Wisconsin Department of Natural Resources... would not be necessary to offset growth in emissions. (h) Approval—On November 15, 1993, the Wisconsin...

  14. 40 CFR 52.1534 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1534 Section 52.1534 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the New Hampshire Department...

  15. 40 CFR 52.2235 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2235 Section 52.2235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone...

  16. 40 CFR 52.1129 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1129 Section 52.1129 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the Massachusetts Department...

  17. 40 CFR 52.1576 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1576 Section 52.1576 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  18. Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind-Hydro Hybrid System

    Science.gov (United States)

    Ram Prabhakar, J.; Ragavan, K.

    2013-07-01

    This article proposes new power management based current control strategy for integrated wind-solar-hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation-demand (G-D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

  19. Enhanced Power Quality and Minimized Peak Current Control in An Inverter based Microgrid under Unbalanced Grid Faults

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Sulligoi, Giorgio

    2016-01-01

    The microgrid inverter experiences the power oscillations and current harmonics in case of the unbalanced grid voltage faults. However, there is a trade-off between power oscillations and current harmonics should be considered in three phase three wire inverter systems during the conventional fault...... ride through control. In order to solve this problem, a novel control strategy is proposed to enhance the output current quality while mitigating the active and reactive output power oscillations. Moreover, a simple current-limited control strategy can be achieved without the necessity of the voltage....../current positive/negative sequence extraction. Finally, the simulation tests of the conventional and proposed control solutions are carried out. The results verify the effectiveness of the proposed strategy....

  20. Design and Implementation of a Control Strategy for Microgrid Containing Renewable Energy Generations and Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Mingchao Xia

    2013-01-01

    Full Text Available Large amount of such renewable energy generations as wind/photovoltaic generations directly connected to grid acting as distributed generations will cause control, protection, security, and safety problems. Microgrid, which has advantages in usage and control of distributed generations, is a promising approach to coordinate the conflict between distributed generations and the grid. Regarded as mobile power storages, batteries of electric vehicles can depress the fluctuation of power through the point of common coupling of microgrid. This paper presents a control strategy for microgrid containing renewable energy generations and electric vehicles. The control strategy uses current control for renewable energy generations under parallel-to-grid mode, and uses master-slave control under islanding mode. Simulations and laboratory experiments prove that the control strategy works well for microgrid containing renewable energy generations and electric vehicles and provides maximum power output of renewable energy and a stable and sustainable running under islanding mode.

  1. New Approaches to Circulating Current Controllers for Modular Multilevel Converters

    Directory of Open Access Journals (Sweden)

    Miguel Moranchel

    2017-01-01

    Full Text Available In the next years, modular multilevel converters (MMCs are going to be a next generation multilevel converters for medium to high voltage conversion applications, such as medium voltage motor drives, medium voltage flexible AC transmission systems (FACTS and high voltage direct current transmission. They provide advantages such as high modularity, availability, low generation of harmonics, etc. However, the circulating current distorts the leg currents and increases the rated current of power devices, which further increases system cost. This paper focuses on analysis and suppression of these currents in a MMC using two algorithms for tracking of harmonics. For this work resonant controllers and repetitive controllers have been selected. Both controllers are analyzed and simulations results are presented. Moreover, the controllers have been tested and validated for a three phase MMC operating as an inverter using a real processing platform based on Zynq by Xilinx and designed to control large multilevel converters and in a real MMC prototype. These results are provided to demonstrate the feasibility of the proposed method.

  2. Gorbachev’s Arms Control Strategy.

    Science.gov (United States)

    1987-01-22

    on- site inspection for verifying nuclear tests as well as for dismantling missiles on Soviet territory. Clearlv Gorbachev wants an arms , -4- control...bring its seismological test equipment to what he called the "holy of holies", the area adjoining the Soviet proving ground near Semipalatinsk to offer...prenotification and observation of military exercises including on- site inspection on Soviet territory. But on the big issues--- nuclear testing , strategic weapons

  3. Evaluation of control strategies in forming processes

    Directory of Open Access Journals (Sweden)

    Calmano Stefan

    2015-01-01

    Full Text Available Products of forming processes are subject to quality fluctuations due to uncertainty in semi-finished part properties as well as process conditions and environment. An approach to cope with these uncertainties is the implementation of a closed-loop control taking into account the actual product properties measured by sensors or estimated by a mathematical process model. Both methods of uncertainty control trade off with a financial effort. In case of sensor integration the effort is the cost of the sensor including signal processing as well as the design and manufacturing effort for integration. In case of an estimation model the effort is mainly determined by the time and knowledge needed to derive the model, identify the parameters and implement the model into the PLC. The risk of mismatch between model and reality as well as the risk of wrong parameter identification can be assumed as additional uncertainty (model uncertainty. This paper evaluates controlled and additional uncertainty by taking into account process boundary conditions like the degree of fluctuations in semi-finished part properties. The proposed evaluation is demonstrated by the analysis of exemplary processes.

  4. Fissura por crack: comportamentos e estratégias de controle de usuários e ex-usuários Ansia de consumo por crack: conductas y estrategias de control de usuarios y ex-usuarios Crack cocaine craving: behaviors and coping strategies among current and former users

    Directory of Open Access Journals (Sweden)

    Tharcila V Chaves

    2011-12-01

    ser herramienta importante para perfeccionar el tratamiento.OBJECTIVE: To understand crack cocaine craving among users and describe craving behaviors and coping strategies. METHODOLOGICAL PROCEDURES: Qualitative study with a non-random criterion sample consisting of 40 current and former crack cocaine users conducted in São Paulo, southeast Brazil, in 2007 and 2008. Respondents were selected using snowball sampling technique. In-depth semi-structured interviews were conducted until theoretical saturation was attained. All interviews were transcribed and content analysis was performed to construct inferences and hypotheses based on the narratives. ANALYSIS OF RESULTS: The respondents showed a similar gender distribution, were 18 to 50 years of age, and had different levels of education. Most were from low-income background. In addition to craving resulting from crack cocaine withdrawal and environmental and emotional cue effects, it was found that crack cocaine itself triggers craving. The latter appeared to be a strong trigger of binge episodes. Binge episodes made them lose their moral values, and act dangerously to get more drug. The most common ways reported to get crack cocaine or money to buy it were: prostitution, manipulation of other people, go into debt, sell personal belongings to buy drug and theft. The respondents reported strategies to overcome their cravings as well as pharmacological and behavioral approaches to prevent cravings such as eating, having sex, playing soccer, working, avoiding social situations of crack use and taking depressants. CONCLUSIONS: Crack cocaine binges are caused by a craving induced by the effects of crack cocaine itself. Users develop self-control strategies to cope with their cravings that may help improve their drug use and treatment effectiveness.

  5. Improving Walkability Through Control Strategies at Signalized Intersections

    Science.gov (United States)

    2017-01-01

    As cities and communities nationwide seek to develop Complete Streets that foster livability and accommodate all modes, signal timing control strategies that include pedestrians in the operational decision process are gaining importance. This researc...

  6. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. [Reserved] 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...: Nitrogen dioxide. [Reserved] ...

  7. Aerodynamic load control strategy of wind turbine in microgrid

    Science.gov (United States)

    Wang, Xiangming; Liu, Heshun; Chen, Yanfei

    2017-12-01

    A control strategy is proposed in the paper to optimize the aerodynamic load of the wind turbine in micro-grid. In grid-connection mode, the wind turbine adopts a new individual variable pitch control strategy. The pitch angle of the blade is rapidly given by the controller, and the pitch angle of each blade is fine tuned by the weight coefficient distributor. In islanding mode, according to the requirements of energy storage system, a given power tracking control method based on fuzzy PID control is proposed. Simulation result shows that this control strategy can effectively improve the axial aerodynamic load of the blade under rated wind speed in grid-connection mode, and ensure the smooth operation of the micro-grid in islanding mode.

  8. Novel strategies for control of fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa; Stocks, Stuart; Sin, Gürkan

    Bioprocesses are inherently sensitive to fluctuations in processing conditions and must be tightly regulated to maintain cellular productivity. Industrial fermentations are often difficult to replicate across production sites or between facilities as the small operating differences in the equipment...... of a fermentation. Industrial fermentation processes are typically operated in fed batch mode, which also poses specific challenges for process monitoring and control. This is due to many reasons including non-linear behaviour, and a relatively poor understanding of the system dynamics. It is therefore challenging...

  9. Magnetohydrodynamic effects of current profile control in reversed field pinches

    International Nuclear Information System (INIS)

    Sovinec, C.R.; Prager, S.C.

    1999-01-01

    Linear and non-linear MHD computations are used to investigate reversed field pinch configurations with magnetic fluctuations reduced through current profile control. Simulations with reduced ohmic drive and moderate auxiliary current drive, represented generically with an electron force term, applied locally in radius near the plasma edge show magnetic fluctuation energies that are orders of magnitude smaller than those in simulations without profile control. The core of the improved configurations has reduced magnetic shear and closed flux surfaces in some cases, and reversal is sustained through the auxiliary current drive. Modes resonant near the edge may become unstable with auxiliary drive, but their saturation levels can be controlled. The space of auxiliary drive parameters is explored, and the ill effects of deviating far from optimal conditions is demonstrated in non-linear simulations. (author)

  10. Design of Current-Controller with PR-regulator for LCL-Filter Based Grid-Connected Converter

    DEFF Research Database (Denmark)

    Zeng, Guohong; Rasmussen, Tonny Wederberg

    2010-01-01

    In the application of LCL-filter based converters, the structure and parameters of current-controller is very important for the system stability and output current quality. This paper presents a filter-capacitor current feedback control scheme for grid-connected converter. The controller...... is consisted of a proportional-resonance regulator and a proportional regulator. Unlike the existing control strategy with unit capacitor current feedback, the proposed method applies the proportional regulator to the feedback path, which can decouple these two regulators, and simplify the tuning process...... of the control strategy and the proposed current controller design method are verified by the simulation results of a 50kVA grid-connected inverter....

  11. Comparison of Power Control Strategies for DFIG Wind Turbines

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Luna, A.; Rodríguez, P.

    2008-01-01

    The classical control techniques for regulating the active and reactive power delivery in doubly fed induction generators (DFIG), for wind power applications, are normally based on voltage oriented control (VOC) strategies. Among these algorithms, those that work in a synchronous reference frame...... VOC strategy able to control the operation of a DFIG in the αβ reference frame, with no need of flux position estimation, something that conducts to a more simple and robust algorithm. In order to evaluate the advantages of this new control proposal, namely VOC-RRF, their performance will be compared...

  12. Control Strategies for DFIG Wind Turbines Under Grid Fault

    DEFF Research Database (Denmark)

    Luna, Alvara; Rolan, A.; Medeiros, G.

    2009-01-01

    The classical control techniques for regulating the active and reactive power delivery in doubly fed induction generators (DFIG), for wind power applications, are normally based on voltage oriented control (VOC) strategies. Among these algorithms, those that work in a synchronous reference frame...... VOC strategy able to control the operation of a DFIG in the αβ reference frame, with no need of flux position estimation, something that conducts to a more simple and robust algorithm. In order to evaluate the advantages of this new control proposal, namely VOC-RRF, their performance will be compared...

  13. Control strategies for VSC-based HVDC transmission system

    DEFF Research Database (Denmark)

    Stan, Ana-Irina; Stroe, Daniel Ioan; Silva, Rodrigo Da

    2011-01-01

    Throughout this paper the modeling and control of the VSC-based HVDC systems are investigated and described. Two different control methods capable of controlling such systems are proposed. Both developed control strategies are implemented in the dq synchronous reference frame. In order to analyze...... the behavior of the developed VSC-based HVDC transmission system two study cases are carried out using MATLAB/Simulink. The results obtained from simulations show acceptable performances, of the proposed strategies, when changes in the reference parameters are considered. The active power flow between...

  14. Flexible Control Strategy for Grid-Connected Inverter under Unbalanced Grid Faults without PLL

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, W.; Zhang, X.

    2015-01-01

    Power oscillation and current quality are the important performance targets for the grid-connected inverter under unbalanced grid faults. Firstly, the inherent reason for the current harmonic and power oscillation of the inverter is discussed with a quantitative analysis. Secondly, a new control...... strategy is proposed to achieve the coordinate control of power and current quality without the need for a phase-locked loop or voltage/current positive/negative sequence extraction calculation. Finally, the experimental tests are conducted under unbalanced grid faults, and the results verify...

  15. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  16. Control and Protection Cooperation Strategy for Voltage Instability

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun

    2012-01-01

    Most cascaded blackouts are caused by unexpected backup relay operations due to low voltage or overload state caused by post fault load restoration dynamics. If such state can be sensed and adjusted appropriately prior to those relay actions, system stability might be sustained. This paper proposed...... a control and protection cooperation strategy to prevent post fault voltage instability. The multi-agent technology is applied for the strategy implementation; the criteria based on wide area measured apparent impedances are defined to choose the control strategy, such as tap changer adjusting or load...

  17. On Ion Cyclotron Current Drive for sawtooth control

    International Nuclear Information System (INIS)

    Eriksson, L.-G.; Johnson, T.; Hellsten, T.; Mayoral, M.-L.; McDonald, D.; Santala, M.; Vries, P. de; Coda, S.; Sauter, O.; Mueck, A.; Buttery, R.J.; Mantsinen, M.J.; Noterdaeme, J.-M.; Westerhof, E.

    2006-01-01

    Experiments using Ion Cyclotron Current Drive (ICCD) to control sawteeth are presented. In particular, discharges demonstrating shortening of fast ion induced long sawteeth reported in [L.-G. Eriksson et al., Physical Review Letters 92, 235004 (2004)] by ICCD have been analysed in detail. Numerical simulations of the ICCD driven currents are shown to be consistent with the experimental observations. They support the hypothesis that an increase of the magnetic shear, due to the driven current, at the surface where the safety factor is unity was the critical factor for the shortening of the sawteeth. In view of the potential utility of ICCD, the mechanisms for the current drive have been further investigated experimentally. This includes the influence of the averaged energy of the resonating ions carrying the current and the spectrum of the launched waves. The results of these experiments are discussed in the light of theoretical considerations. (author)

  18. Current control for magnetized plasma in direct-current plasma-immersion ion implantation

    International Nuclear Information System (INIS)

    Tang Deli; Chu, Paul K.

    2003-01-01

    A method to control the ion current in direct-current plasma-immersion ion implantation (PIII) is reported for low-pressure magnetized inductively coupled plasma. The ion current can be conveniently adjusted by applying bias voltage to the conducting grid that separates plasma formation and implantation (ion acceleration) zones without the need to alter the rf input power, gas flux, or other operating conditions. The ion current that diminishes with an increase in grid bias in magnetized plasmas can be varied from 48 to 1 mA by increasing the grid voltage from 0 to 70 V at -50 kV sample bias and 0.5 mTorr hydrogen pressure. High implantation voltage and monoenergetic immersion implantation can now be achieved by controlling the ion current without varying the macroscopic plasma parameters. The experimental results and interpretation of the effects are presented in this letter. This technique is very attractive for PIII of planar samples that require on-the-fly adjustment of the implantation current at high implantation voltage but low substrate temperature. In some applications such as hydrogen PIII-ion cut, it may obviate the need for complicated sample cooling devices that must work at high voltage

  19. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    International Nuclear Information System (INIS)

    Leng Min-Rui; Zhou Guo-Hua; Zhang Kai-Tun; Li Zhen-Hua

    2015-01-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. (paper)

  20. Two-dimensional effects in the problem of tearing modes control by electron cyclotron current drive

    International Nuclear Information System (INIS)

    Comisso, L.; Lazzaro, E.

    2010-01-01

    The design of means to counteract robustly the classical and neoclassical tearing modes in a tokamak by localized injection of an external control current requires an ever growing understanding of the physical process, beyond the Rutherford-type zero-dimensional models. Here a set of extended magnetohydrodynamic nonlinear equations for four continuum fields is used to investigate the two-dimensional effects in the response of the reconnecting modes to specific inputs of the localized external current. New information is gained on the space- and time-dependent effects of the external action on the two-dimensional structure of magnetic islands, which is very important to formulate applicable control strategies.

  1. A Reactive Power Based Reference Model for Adaptive Control Strategy in a SEIG

    Directory of Open Access Journals (Sweden)

    M. A. Taghikhani

    2018-02-01

    Full Text Available In this paper, a new control strategy is proposed for a three-phase squirrel-cage self-excited induction generator (SEIG connected to a variable speed wind turbine in autonomous mode. In order to improve the dynamic performance of the mentioned vector control system, a model reference adaptive controller is used for online rotor time constant estimation. Thus, the main drawbacks of this method, which include the effects of the changes in machine parameters on rotor flux estimation, slip speed, the creation of instability problems and the system leaving vector control mode, are resolved. In this control strategy, a PI controller is used to control the dc voltage and three similar hysteresis current controllers (HCC are used to control the switching of IGBTs. The results of the dynamic simulation indicate the desirable performance of the proposed system.

  2. Job monitoring on the WLCG scope: Current status and new strategy

    International Nuclear Information System (INIS)

    Andreeva, Julia; Casey, James; Gaidioz, Benjamin; Karavakis, Edward; Kokoszkiewicz, Lukasz; Lanciotti, Elisa; Maier, Gerhild; Rodrigues, Daniele Filipe Rocha Da Cuhna; Rocha, Ricardo; Saiz, Pablo; Sidorova, Irina; Boehm, Max; Belov, Sergey; Tikhonenko, Elena; Dvorak, Frantisek; Krenek, Ales; Mulac, Milas; Sitera, Jiri; Kodolova, Olga; Vaibhav, Kumar

    2010-01-01

    Job processing and data transfer are the main computing activities on the WLCG infrastructure. Reliable monitoring of the job processing on the WLCG scope is a complicated task due to the complexity of the infrastructure itself and the diversity of the currently used job submission methods. The paper will describe current status and the new strategy for the job monitoring on the WLCG scope, covering primary information sources, job status changes publishing, transport mechanism and visualization.

  3. Control of Maillard Reactions in Foods: Strategies and Chemical Mechanisms.

    Science.gov (United States)

    Lund, Marianne N; Ray, Colin A

    2017-06-14

    Maillard reactions lead to changes in food color, organoleptic properties, protein functionality, and protein digestibility. Numerous different strategies for controlling Maillard reactions in foods have been attempted during the past decades. In this paper, recent advances in strategies for controlling the Maillard reaction and subsequent downstream reaction products in food systems are critically reviewed. The underlying mechanisms at play are presented, strengths and weaknesses of each strategy are discussed, and reasonable reaction mechanisms are proposed to reinforce the evaluations. The review includes strategies involving addition of functional ingredients, such as plant polyphenols and vitamins, as well as enzymes. The resulting trapping or modification of Maillard targets, reactive intermediates, and advanced glycation endproducts (AGEs) are presented with their potential unwanted side effects. Finally, recent advances in processing for control of Maillard reactions are discussed.

  4. UAV Robust Strategy Control Based on MAS

    Directory of Open Access Journals (Sweden)

    Jian Han

    2014-01-01

    Full Text Available A novel multiagent system (MAS has been proposed to integrate individual UAV (unmanned aerial vehicle to form a UAV team which can accomplish complex missions with better efficiency and effect. The MAS based UAV team control is more able to conquer dynamic situations and enhance the performance of any single UAV. In this paper, the MAS proposed and established combines the reacting and thinking abilities to be an initiative and autonomous hybrid system which can solve missions involving coordinated flight and cooperative operation. The MAS uses BDI model to support its logical perception and to classify the different missions; then the missions will be allocated by utilizing auction mechanism after analyzing dynamic parameters. Prim potential algorithm, particle swarm algorithm, and reallocation mechanism are proposed to realize the rational decomposing and optimal allocation in order to reach the maximum profit. After simulation, the MAS has been proved to be able to promote the success ratio and raise the robustness, while realizing feasibility of coordinated flight and optimality of cooperative mission.

  5. Control of bootstrap current in the pedestal region of tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Shaing, K. C. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China); Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53796 (United States); Lai, A. L. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China)

    2013-12-15

    The high confinement mode (H-mode) plasmas in the pedestal region of tokamaks are characterized by steep gradient of the radial electric field, and sonic poloidal U{sub p,m} flow that consists of poloidal components of the E×B flow and the plasma flow velocity that is parallel to the magnetic field B. Here, E is the electric field. The bootstrap current that is important for the equilibrium, and stability of the pedestal of H-mode plasmas is shown to have an expression different from that in the conventional theory. In the limit where ‖U{sub p,m}‖≫ 1, the bootstrap current is driven by the electron temperature gradient and inductive electric field fundamentally different from that in the conventional theory. The bootstrap current in the pedestal region can be controlled through manipulating U{sub p,m} and the gradient of the radial electric. This, in turn, can control plasma stability such as edge-localized modes. Quantitative evaluations of various coefficients are shown to illustrate that the bootstrap current remains finite when ‖U{sub p,m}‖ approaches infinite and to provide indications how to control the bootstrap current. Approximate analytic expressions for viscous coefficients that join results in the banana and plateau-Pfirsch-Schluter regimes are presented to facilitate bootstrap and neoclassical transport simulations in the pedestal region.

  6. Concepts Concerning 'Disease\\' Causation, Control, and the current ...

    African Journals Online (AJOL)

    There is an ethical necessity that doctors understand the complex social, political, environmental and economic dynamics involved in infectious disease outbreaks. This article discusses some important concepts concerning 'disease' causation and control with specific reference to the current cholera outbreak in Zimbabwe ...

  7. High performance current controller for particle accelerator magnets supply

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  8. Fault Ride Though Control of Photovoltaic Grid-connected Inverter with Current-limited Capability under Offshore Unbalanced Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi

    2016-01-01

    The photovoltaic (PV) inverter installed on board experiences the excessive current stress in case of the offshore unbalanced voltage fault ride through (FRT), which significantly affects the operation reliability of the power supply system. In order to solve the problem, the inherent mechanism...... of the excessive current phenomenon with the conventional fault ride through control is discussed. The quantitative analysis of the current peak value is conducted and a new current-limiting control strategy is proposed to achieve the flexible power control and successful fault ride through in a safe current...

  9. Delivering Communication Strategy Training for People with Aphasia: What Is Current Clinical Practice?

    Science.gov (United States)

    Beckley, Firle; Best, Wendy; Beeke, Suzanne

    2017-01-01

    Background: Communication strategy training (CST) is a recognized part of UK speech and language therapists' (SLTs) role when working with a person with aphasia. Multiple CST interventions have been published but, to date, there are no published studies exploring clinical practice in this area. Aims: To investigate UK SLTs' current CST practices.…

  10. Parent Retrospective Recollections of Bullying and Current Views, Concerns, and Strategies to Cope with Children's Bullying

    Science.gov (United States)

    Cooper, Leigh A.; Nickerson, Amanda B.

    2013-01-01

    In this study, parent history of bullying was examined in terms of general involvement with bullying, specific types of bullying experienced, level of hurtfulness associated with the experience, and when bullying occurred. Parent current views, levels of concern, and strategies used to cope with bullying were also evaluated. Finally, the…

  11. Modelling the transport system in China and evaluating the current strategies towards the sustainable transport development

    DEFF Research Database (Denmark)

    Liu, W.; Lund, H.; Mathiesen, B.V.

    2013-01-01

    in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13...

  12. Neuroinspired control strategies with applications to flapping flight

    Science.gov (United States)

    Dorothy, Michael Ray

    pattern generators is confirmed with a robotic bat on a 3-DOF pendulum platform. An aerodynamic model for the robotic bat based on the complex wing kinematics is presented. Closed loop experiments show that control dimension reduction is achievable - unstable longitudinal modes are stabilized and controlled using only two control parameters. A transition of flight modes, from flapping to gliding and vice-versa, is demonstrated within the CPG control scheme. The second major thrust is inspired by this idea that mode switching is useful. Many bats and birds adopt a mixed strategy of flapping and gliding to provide agility when necessary and to increase overall efficiency. This work explores dwell time constraints on switched systems with multiple, possibly disparate invariant limit sets. We show that, under suitable conditions, trajectories globally converge to a superset of the limit sets and then remain in a second, larger superset. We show the effectiveness of the dwell-time conditions by using examples of nonlinear switching limit cycles from our work on flapping flight. This level of abstraction has been found to be useful in many ways, but it also produces its own challenges. For example, we discuss death of oscillation which can occur for many limit-cycle controllers and the difficulty in incorporating fast, high-displacement reflex feedback. This leads us to our third major thrust - considering biologically realistic neuron circuits instead of a limit cycle abstraction. Biological neuron circuits are incredibly diverse in practice, giving us a convincing rationale that they can aid us in our quest for flexibility. Nevertheless, that flexibility provides its own challenges. It is not currently known how most biological neuron circuits work, and little work exists that connects the principles of a neuron circuit to the principles of control theory. We begin the process of trying to bridge this gap by considering the simplest of classical controllers, PD control. We

  13. Current strategies in multiphasic scaffold design for osteochondral tissue engineering: A review.

    Science.gov (United States)

    Yousefi, Azizeh-Mitra; Hoque, Md Enamul; Prasad, Rangabhatala G S V; Uth, Nicholas

    2015-07-01

    The repair of osteochondral defects requires a tissue engineering approach that aims at mimicking the physiological properties and structure of two different tissues (cartilage and bone) using specifically designed scaffold-cell constructs. Biphasic and triphasic approaches utilize two or three different architectures, materials, or composites to produce a multilayered construct. This article gives an overview of some of the current strategies in multiphasic/gradient-based scaffold architectures and compositions for tissue engineering of osteochondral defects. In addition, the application of finite element analysis (FEA) in scaffold design and simulation of in vitro and in vivo cell growth outcomes has been briefly covered. FEA-based approaches can potentially be coupled with computer-assisted fabrication systems for controlled deposition and additive manufacturing of the simulated patterns. Finally, a summary of the existing challenges associated with the repair of osteochondral defects as well as some recommendations for future directions have been brought up in the concluding section of this article. © 2014 Wiley Periodicals, Inc.

  14. Optimized Control Strategy For Over Loaded Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Wisniewski, Rafal

    2015-01-01

    controller tuning for a given wind turbine. It also enables a very safe and robust comparison between a new control strategy and the present one. Main body of abstract Is it true that power de-rating indeed the best way to reduce loads? The power de-rating approach has the drawback of only indirectly...

  15. Strategies for controlling pollution from vehicular emissions in Beijing

    International Nuclear Information System (INIS)

    Wang, Qidong; He, Kebin; Li, Tiejun; Fu, Lixin

    2002-01-01

    The paper describes the severe situation of vehicular emission in Beijing and discusses the following mitigation strategies: Improving fuel quality, controlling the exhaust from new vehicles, controlling the emissions from vehicles in use through e.g. Inspection Maintenance (I/M), renovating in-use vehicles and scrapping of old vehicles and road infrastructure and traffic policies. (Author)

  16. Oxygen uptake rate (OUR) control strategy for improving avermectin B

    African Journals Online (AJOL)

    Glucose metabolism plays a crucial role in the process of avermectin B1a biosynthesis. Controlling glucose feeding based on oxygen uptake rate (OUR) was established to improve the efficiency of avermectin B1a production. The result showed that avermectin B1a production was greatly enhanced by OUR control strategy.

  17. 40 CFR 52.1126 - Control strategy: Sulfur oxides.

    Science.gov (United States)

    2010-07-01

    ... Department of Environmental Quality Engineering.). Gardner State Hospital, Gardner. Grafton State Hospital... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Sulfur oxides. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Massachusetts § 52.1126 Control...

  18. Plant-wide Control Strategy for Improving Produced Water Treatment

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Pedersen, Simon; Løhndorf, Petar Durdevic

    2016-01-01

    This work focuses on investigation and development of an innovative Produced Water Treatment (PWT) technology for offshore oil & gas production by employing the model-based plant-wide control strategy. The key contributions lie in two folds: (i) the advanced anti-slug analysis and control...

  19. Strategies for controlling pollution from vehicular emissions in Beijing

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qidong; He, Kebin; Li, Tiejun; Fu, Lixin

    2002-07-01

    The paper describes the severe situation of vehicular emission in Beijing and discusses the following mitigation strategies: Improving fuel quality, controlling the exhaust from new vehicles, controlling the emissions from vehicles in use through e.g. Inspection Maintenance (I/M), renovating in-use vehicles and scrapping of old vehicles and road infrastructure and traffic policies. (Author)

  20. Short Horizon Control Strategies for an Alternating Activated Sludge Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard

    1996-01-01

    Three control strategies allowing improved operational flexibility of an alternating type activated sludge process are presented in a unified model based framework. The control handles employed are the addition rate of an external carbon source to denitrification, the cycle length, and the dissol...

  1. Multi-Objective Predictive Balancing Control of Battery Packs Based on Predictive Current

    Directory of Open Access Journals (Sweden)

    Wenbiao Li

    2016-04-01

    Full Text Available Various balancing topology and control methods have been proposed for the inconsistency problem of battery packs. However, these strategies only focus on a single objective, ignore the mutual interaction among various factors and are only based on the external performance of the battery pack inconsistency, such as voltage balancing and state of charge (SOC balancing. To solve these problems, multi-objective predictive balancing control (MOPBC based on predictive current is proposed in this paper, namely, in the driving process of an electric vehicle, using predictive control to predict the battery pack output current the next time. Based on this information, the impact of the battery pack temperature caused by the output current can be obtained. Then, the influence is added to the battery pack balancing control, which makes the present degradation, temperature, and SOC imbalance achieve balance automatically due to the change of the output current the next moment. According to MOPBC, the simulation model of the balancing circuit is built with four cells in Matlab/Simulink. The simulation results show that MOPBC is not only better than the other traditional balancing control strategies but also reduces the energy loss in the balancing process.

  2. Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

    Directory of Open Access Journals (Sweden)

    Zhijian Fang

    2018-03-01

    Full Text Available In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feedback inner loop is proposed to increase the control system damping, improving dynamic performance. The modeling and design methodology for the LLC resonant converter are also presented in this paper. A frequency analysis is conducted to verify the accuracy of the simplified model. Finally, a 200 W LLC resonant converter prototype is built to verify the effectiveness of the proposed control strategy. Compared to a traditional single-loop controller, the settling time and voltage droop were reduced from 10.8 ms to 8.6 ms and from 6.8 V to 4.8 V, respectively, using the proposed control strategy.

  3. A new control strategy for nuclear power reactors

    International Nuclear Information System (INIS)

    Wakabayashi, H.; Sasaki, K.; Takegaki, M.

    1990-01-01

    A new automatic direct digital control strategy for nuclear power reactors is presented. It is based on a simple control logic of comparison between the available time (the time for the error signal to disappear) and the required time (the time for the time derivative to match that of the target trend). The method aims to control the system to an acceptable state within a minimum time under a number of restraints. The control capability of the method is shown for two typical transients. This method is generally applicable to process control in which time-optimal control based on the maximum principle is sought

  4. Adaptive Landing Gear: Optimum Control Strategy and Potential for Improvement

    Directory of Open Access Journals (Sweden)

    Grzegorz Mikułowski

    2009-01-01

    Full Text Available An adaptive landing gear is a landing gear (LG capable of active adaptation to particular landing conditions by means of controlled hydraulic force. The objective of the adaptive control is to mitigate the peak force transferred to the aircraft structure during touch-down, and thus to limit the structural fatigue factor. This paper investigates the ultimate limits for improvement due to various strategies of active control. Five strategies are proposed and investigated numerically using a~validated model of a real, passive landing gear as a reference. Potential for improvement is estimated statistically in terms of the mean and median (significant peak strut forces as well as in terms of the extended safe sinking velocity range. Three control strategies are verified experimentally using a laboratory test stand.

  5. Regulatory controls for NORM contamination: Emerging issues and strategies

    International Nuclear Information System (INIS)

    Wennerberg, Linda

    1992-01-01

    Naturally occurring and accelerator-produced radioactive material (NORM) faces the increasing likelihood of federal or state regulatory control. Public concern and limited preliminary survey data fuel the debate over the necessity, approach, and jurisdiction of a NORM regulatory strategy. This debate requires the resolution of technical controversies and potentially competing state and federal agency interests. An additional facet of the debate is the impact of regulation upon traditionally non-nuclear industries, such as oil and gas production. Regulatory response has been initiated in several states, such as Louisiana's controls on equipment used in oil and gas production, to control specific industrial activities which generate NORM. A more comprehensive, generic federal strategy to control NORM contamination is also under review by the Environmental Protection Agency. This paper will detail the emerging technical issues, federal and state regulatory strategies under consideration, and evaluate the efficacy of selected regulatory approaches. (author)

  6. Controlling chaos in the current-driven ion acoustic instability

    International Nuclear Information System (INIS)

    Fukuyama, T.; Taniguchi, K.; Kawai, Y.

    2002-01-01

    Control of intermittent chaos caused by the current-driven ion acoustic instability is attempted and the controlling mechanism is investigated. When a small negative dc voltage is applied to the chaotic system as a perturbation, the system changes from a chaotic state to a periodic state while maintaining the instability, indicating that the chaotic state caused by the ion acoustic instability is well controlled by applying a small negative dc voltage. A hysteresis structure is observed on the V-I curve of the mesh grid to which the negative dc voltage to control is applied. Furthermore, when a negative dc voltage is applied to the state which shows a laminar structure existing under same experimental conditions, the system becomes chaotic via a bifurcation. Driven-chaos is excited when a negative dc voltage is applied to the laminar state. Applying a small negative dc voltage leads to controlling intermittent chaos while exciting driven-chaos

  7. Current control of PMSM based on maximum torque control reference frame

    Science.gov (United States)

    Ohnuma, Takumi

    2017-07-01

    This study presents a new method of current controls of PMSMs (Permanent Magnet Synchronous Motors) based on a maximum torque control reference frame, which is suitable for high-performance controls of the PMSMs. As the issues of environment and energy increase seriously, PMSMs, one of the AC motors, are becoming popular because of their high-efficiency and high-torque density in various applications, such as electric vehicles, trains, industrial machines, and home appliances. To use the PMSMs efficiently, a proper current control of the PMSMs is necessary. In general, a rotational coordinate system synchronizing with the rotor is used for the current control of PMSMs. In the rotating reference frame, the current control is easier because the currents on the rotating reference frame can be expressed as a direct current in the controller. On the other hand, the torque characteristics of PMSMs are non-linear and complex; the PMSMs are efficient and high-density though. Therefore, a complicated control system is required to involve the relation between the torque and the current, even though the rotating reference frame is adopted. The maximum torque control reference frame provides a simpler way to control efficiently the currents taking the torque characteristics of the PMSMs into consideration.

  8. A Lyapunov Stability Theory-Based Control Strategy for Three-Level Shunt Active Power Filter

    Directory of Open Access Journals (Sweden)

    Yijia Cao

    2017-01-01

    Full Text Available The three-phase three-wire neutral-point-clamped shunt active power filter (NPC-SAPF, which most adopts classical closed-loop feedback control methods such as proportional-integral (PI, proportional-resonant (PR and repetitive control, can only output 1st–25th harmonic currents with 10–20 kHz switching frequency. The reason for this is that the controller design must make a compromise between system stability and harmonic current compensation ability under the condition of less than 20 kHz switching frequency. To broaden the bandwidth of the compensation current, a Lyapunov stability theory-based control strategy is presented in this paper for NPC-SAPF. The proposed control law is obtained by constructing the switching function on the basis of the mathematical model and the Lyapunov candidate function, which can avoid introducing closed-loop feedback control and keep the system globally asymptotically stable. By means of the proposed method, the NPC-SAPF has compensation ability for the 1st–50th harmonic currents, the total harmonic distortion (THD and each harmonic content of grid currents satisfy the requirements of IEEE Standard 519-2014. In order to verify the superiority of the proposed control strategy, stability conditions of the proposed strategy and the representative PR controllers are compared. The simulation results in MATLAB/Simulink (MathWorks, Natick, MA, USA and the experimental results obtained on a 6.6 kVA NPC-SAPF laboratory prototype validate the proposed control strategy.

  9. A microgrid cluster structure and its autonomous coordination control strategy

    DEFF Research Database (Denmark)

    Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

    2018-01-01

    This paper proposes a microgrid cluster structure and its autonomous coordination control strategy. Unlike existing microgrids that are purely AC or DC, the microgrid cluster studied here is an interconnected system with multiple AC and DC microgrids, which enables mutual power support among...... control method combining the normalized droop-based control and adaptive control is proposed for PEU, which can effectively realize mutual power support among microgrids and reduce the bus voltage or frequency deviation in microgrids. In addition, the adaptive control strategy of PEU can ensure...... that the bigger the normalized index of microgrid is, the larger the active power exchange coefficient is, which can make all of microgrids operate around the rated state as much as possible. Besides, EP is mainly used to balance the system power, and the hierarchical coordinated control method of EP is proposed...

  10. Relationship Between Strategy Shaping and Management Control Systems

    Directory of Open Access Journals (Sweden)

    Marcia Athayde Moreira

    2017-04-01

    Full Text Available This research analyzed the interactions between strategy shaping and management control systems, having as parameter of analysis the system of levers of control recommended by Simons (1995. A multiple case study was carried out of two companies in the construction sector in Brazil. It was found that these companies use generic niche strategies to sell the properties they have built. One of these companies uses long-term planning while the other is guided by short-term perspectives and perceptions. Both companies employ various formal control tools. It was noted, however, that some of these tools exist for the purpose of meeting the requirements of standards and audits established by certifying bodies and are not being used as tools for decision making. It was thus concluded that the relationship between managerial controls and the shaping of strategy in these organizations occurs in a passive way, with the management control systems serving as guarantors of the accomplishment of organizational strategies and goals, but not being used effectively to identify opportunities or as a source for shaping new strategies.

  11. Reading comprehension metacognitive strategies as a means for controlling behavior

    Directory of Open Access Journals (Sweden)

    Dinorah Aladina Caballero López

    2014-07-01

    Full Text Available Textual comprehension implies the use of various metacognitive strategies by the students when they have to face a text to be competent readers. That is why the objective of this article is to illustrate the application of metacognitive strategies in order to achieve an efficient textual comprehension, taking into account the self – regulation the student exerts over his own learning process. It is applied as the main method historical-logical studies based on a professional-researching systematic practice; at the same time observation is largely used. The main result is the introduction of metacognitive strategies in reading comprehension, which subsequently favor the self-control of personal behavior. The article is the result of a research project sponsored by the department of Special Education. Key words: reading comprehension, metacognitive strategies, behavior self-control.

  12. Adaptive Hysteresis Band Current Control (AHB) with PLL of Grid Side Converter-Based Wind Power Generation System

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Li, Lijuan

    2011-01-01

    Adaptive hysteresis band current control(AHB CC) is used to control the three-phase grid currents by means of grid side converter in wind power generation system in this paper. AHB has reached the good purpose with PLL (Lock phase loop). First the mathematical models of each part are given......, transformer and grid, and control parts, etc. The simulation results have verified that the control strategy is feasible to fit for control of gird currents, active power, reactive power and DC-link voltage in wind power generation system....

  13. Control of optically induced currents in semiconductor crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kohli, Kapil Kumar

    2010-06-01

    The generation and control of optically induced currents has the potential to become an important building block for optical computers. Here, shift and rectification currents are investigated that emerge from a divergence of the optical susceptibility. It is known that these currents react to the shape of the impinging laser pulse, and especially to the shape of the pulse envelope. The main goal is the systematic manipulation of the pulse envelope with an optical pulse shaper that is integrated into a standard THz emission setup. The initial approach, the chirping of the laser pulse only has a weak influence on the envelope and the currents. Instead, a second approach is suggested that uses the combined envelope of a phase-stable pulse-pair as a parameter. In a laser pulse, the position of the maxima of the electrical field and the pulse envelope are shifted relative to each other. This shift is known as the Carrier-Envelope Phase (CEP). It is a new degree of freedom that is usually only accessible in specially stabilized systems. It is shown, that in a phase-stable pulse-pair, at least the relative CEP is usable as a new degree of freedom. It has a great influence on the shape of the pulse envelope and thus on the current density. It is shown that this approach enables the coherent control of the current density. The experiments are corroborated by a theoretical model of the system. The potential of this approach is demonstrated in an application. A framework is presented that uses an iterative genetic algorithm to create arbitrarily shaped THz traces. The algorithm controls the optical pulse shaper, and varies the phase of the impinging laser pulses until the desired target trace is found. (orig.)

  14. Best control strategy for unified power quality conditioner (UPQC) based on simulation

    Energy Technology Data Exchange (ETDEWEB)

    Shayanfar, H.A. [Iran Univ. of Science and Technology, Tehran (Iran, Islamic Republic of). Dept. of Electrical Engineering; Tabatabaei, N.M. [Azarbaijan Univ. of Tarbiat Moallem, Tabriz (Iran, Islamic Republic of). Dept. of Electrical Engineering; Mokhtarpour, A. [Islamic Azad Univ., Tabriz (Iran, Islamic Republic of). Dept. of Electrical Engineering

    2007-07-01

    Electronic devices used in both industry and residences need high-quality energy to work properly. Unified Power Quality Conditioners (UPQC) solve any power quality problems faced by these devices. Three new control strategies for UPQCs were presented and their operation was investigated and compared using the MATLAB Simulink simulation software package. A UPQC consists of a Shunt-Active Filter and a Series Active Filter with a common direct current link to compensate for any source currents and delivered voltage to the load. As such, it isolates the utility from current quality problems associated with load. It also isolates the load from the voltage quality problems of the utility. In the first control strategy, the Parallel Active Filter (PAF) and Series Active Filter (SAF) are based on the Fourier transform theory. In the second control strategy, the Parallel Active Filter is based on the power quality theory and the Series Active Filter is based on the Fourier transform theory. In the third control strategy, the Parallel Active Filter is based on Fourier transform theory and the Series Active Filter is based on positive sequence detection. Operating the PAF using these methods compensates for reactive power and current harmonics, while operating the SAF compensates for imbalances, voltage harmonics and positive and zero sequences of utility voltages. MATLAB simulation software was used to explain the compensation resolution and speed of the 3 new control strategies. According to simulation test results, it was concluded that the best compensation speed and resolution can be obtained using the third control strategy. 7 refs., 2 tabs., 24 figs.

  15. HOM frequency control of SRF cavity in high current ERLs

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan

    2018-03-01

    The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

  16. Control Strategies for the DAB Based PV Interface System.

    Directory of Open Access Journals (Sweden)

    Hadi M El-Helw

    Full Text Available This paper presents an interface system based on the Dual Active Bridge (DAB converter for Photovoltaic (PV arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O Maximum Power Point Tracking (MPPT technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

  17. Control of the current density profile with lower hybrid current drive on PBX-M

    International Nuclear Information System (INIS)

    Bell, R.E.; Bernabei, S.; Chu, T.K.; Gettelfinger, G.; Greenough, N.; Hatcher, R.; Ignat, D.; Jardin, S.; Kaita, R.; Kaye, S.; Kozub, T.; Kugel, H.; LeBlanc, B.; Okabayashi, M.; Paul, S.; Sauthoff, N.; Sesnic, S.; Sun, Y.; Takahashi, H.; Tighe, W.; Valeo, E.; von Goeler, S.; Jones, S.; Kesner, J.; Luckhardt, S.; Paoletti, F.; Levinton, F.; Timini, F.

    1993-07-01

    Lower hybrid current drive (LHCD) is being explored as a means to control the current density profile on PBX-M with the goal of raising the central safety factor q(O) to values of 1.5-2 to facilitate access to a full-volume second stable regime. Initial experiments have been conducted with up to 400 kW of 4.6 GHz LH power in circular and indented plasmas with modest parameters. A tangential-viewing two-dimensional hard x-ray imaging diagnostic has been used to observe the bremsstrahlung emission from the suprathermal electrons generated during LHCD. Hollow hard x-ray images have indicated off-axis localization of the driven current. A serious obstacle to the control of the current density profile with LHCD is the concomitant generation of MHD activity, which can seriously degrade the confinement of suprathermal electrons. By combining neutral beam injection with LHCD, an MHD-free condition has been obtained where q(O) is raised above 1

  18. Control strategies and sensitivity analysis of anthroponotic visceral leishmaniasis model.

    Science.gov (United States)

    Zamir, Muhammad; Zaman, Gul; Alshomrani, Ali Saleh

    2017-12-01

    This study proposes a mathematical model of Anthroponotic visceral leishmaniasis epidemic with saturated infection rate and recommends different control strategies to manage the spread of this disease in the community. To do this, first, a model formulation is presented to support these strategies, with quantifications of transmission and intervention parameters. To understand the nature of the initial transmission of the disease, the reproduction number [Formula: see text] is obtained by using the next-generation method. On the basis of sensitivity analysis of the reproduction number [Formula: see text], four different control strategies are proposed for managing disease transmission. For quantification of the prevalence period of the disease, a numerical simulation for each strategy is performed and a detailed summary is presented. Disease-free state is obtained with the help of control strategies. The threshold condition for globally asymptotic stability of the disease-free state is found, and it is ascertained that the state is globally stable. On the basis of sensitivity analysis of the reproduction number, it is shown that the disease can be eradicated by using the proposed strategies.

  19. Novel Control Strategy for VSI and CSI Active Filters and Comparing These Two Types of Filters

    Directory of Open Access Journals (Sweden)

    Gholam Reza Arab

    2014-10-01

    Full Text Available Recently to eliminate the harmonics and improve the power factor of the power networks, much attention has been attracted to active filters. The advantages of these filters are lower volume and their better compensating characteristics than the passive filters. In conventional sliding mode controllers, the source current waveform is fluctuated in near to zero values. In this paper, using a new sliding technique, lower Total Harmonic Distortion (THD in source current is obtained and the current waveform is improved. As well as, two novel control strategies for two types of active filters, VSI and CSI is proposed and then these two types of filters are compared to reduce THD value of source current.The proposed controlled strategies are simulated by MATLAB/Simulink. The Simulation results confirm that the proposed strategies reduce the THD of source current more than other strategies, and active filter based on CSI has a better performance than active filter based on VSI with a dead time area (for avoiding short circuit of the source in high powers.

  20. Innovation in Active Vibration Control Strategy of Intelligent Structures

    Directory of Open Access Journals (Sweden)

    A. Moutsopoulou

    2014-01-01

    Full Text Available Large amplitudes and attenuating vibration periods result in fatigue, instability, and poor structural performance. In light of past approaches in this field, this paper intends to discuss some innovative approaches in vibration control of intelligent structures, particularly in the case of structures with embedded piezoelectric materials. Control strategies are presented, such as the linear quadratic control theory, as well as more advanced theories, such as robust control theory. The paper presents sufficiently a recognizable advance in knowledge of active vibration control in intelligent structures.

  1. High-Level Waste (HLW) Feed Process Control Strategy

    International Nuclear Information System (INIS)

    STAEHR, T.W.

    2000-01-01

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system

  2. Development of an overload control strategy for the Republic of Senegal

    CSIR Research Space (South Africa)

    Nordengen, Paul A

    2006-09-01

    Full Text Available , particularly because there are currently no weighbridges in the country being used for overload control law enforcement. Recognising the need for an effective overload strategy for Senegal, the Ministry of Public Works and Transport decided to initiate a study...

  3. Development of a vehicle load control strategy for Malawi for the period 2016 to 2020

    CSIR Research Space (South Africa)

    Roux, MP

    2016-07-01

    Full Text Available Strategy and development of a five-year implementation plan for significantly improving the Directorate’s current capacity to effectively manage and enforce axle load control. Specific objectives were to: a) Assist the DRTSS to undertake an extensive...

  4. Myoelectric hand prosthesis force control through servo motor current feedback.

    Science.gov (United States)

    Sono, Tálita Saemi Payossim; Menegaldo, Luciano Luporini

    2009-10-01

    This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control.

  5. A new control strategy of SMES for mitigating subsynchronous oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, Mohsen, E-mail: m.farahani@basu.ac.ir [Bu-Ali Sina University, Department of Electrical Engineering, Hamedan-Iran (Iran, Islamic Republic of)

    2012-12-14

    This paper proposes a new strategy to mitigate the subsynchronous oscillations in power systems compensated by series capacitors via control of active power of superconducting magnetic energy storage (SMES) unit. The strategy is based on the generator acceleration signal. So, the SMES absorbs or generates the energy imbalance caused by different disturbances in the power system and suppresses the subsynchronous oscillations. The chaotic optimization algorithm (COA) is used to achieve the optimal parameter of the proposed controller. To validate the capability of the SMES in damping oscillations, some simulations with different disturbances are performed on the first model of IEEE second benchmark model. All the simulation results show that the subsynchronous resonance as well as low frequency oscillation (LFO) is satisfactorily mitigated by the SMES controlled by the proposed strategy.

  6. A new control strategy of SMES for mitigating subsynchronous oscillations

    International Nuclear Information System (INIS)

    Farahani, Mohsen

    2012-01-01

    This paper proposes a new strategy to mitigate the subsynchronous oscillations in power systems compensated by series capacitors via control of active power of superconducting magnetic energy storage (SMES) unit. The strategy is based on the generator acceleration signal. So, the SMES absorbs or generates the energy imbalance caused by different disturbances in the power system and suppresses the subsynchronous oscillations. The chaotic optimization algorithm (COA) is used to achieve the optimal parameter of the proposed controller. To validate the capability of the SMES in damping oscillations, some simulations with different disturbances are performed on the first model of IEEE second benchmark model. All the simulation results show that the subsynchronous resonance as well as low frequency oscillation (LFO) is satisfactorily mitigated by the SMES controlled by the proposed strategy.

  7. [Integrated prevention and control strategy for dengue in Mesoamerica].

    Science.gov (United States)

    Gómez-Dantés, Héctor; San Martín, José Luis; Danis-Lozano, Rogelio; Manrique-Saide, Pablo

    2011-01-01

    Dengue in the Americas is a public health problem in ascent. The control strategies have not been effective when sustained in the intensive use of insecticides and poor community participation. The Mesoamerican Initiative for the Prevention and the Integrated Control of Dengue synthesizes the works generated by the Integrated Strategy of the Pan-American Health Organization (PAHO) and the risks stratification strategy designed by the countries of the Mesoamerican region. The objective is to progressively reduce the incidence of dengue cases until a 50% reduction is reached over a five years period. This document describes the elements for the risk stratification, the activities for prevention and control organized by levels of intensity and frequency and the indicators used to pursuit the objectives. To face the dispersion of the problem a concentration of efforts for control in the areas of greater risk is presented; the opportunity in the detection of cases is highlighted to tackle the fast dissemination of the infection; focus on the most productive breeding sites is proposed to battle against the vast dissemination of the breeding sites; and the severity of the infection must be addressed by capable clinical human resources. This strategy was designed along with the national representatives of the control programs to create master plans that provided the basis for the integrated prevention and control of dengue in the Mesoamerican region.

  8. Research on Control Strategy of Free-Piston Stirling Power Generating System

    Directory of Open Access Journals (Sweden)

    Jigui Zheng

    2017-10-01

    Full Text Available As a clean and fuel adaptive alternative power plant, the Stirling power generating system has drawn attention of experts and scholars in the energy field. In practical application, the instability of free-piston Stirling power generating system caused by abrupt load change is an inevitable problem. Thus, methods to improve the output frequency response and stability of the free-piston Stirling power generating system are necessary. The model of free-piston Stirling power generating system is built by isothermal analysis firstly, and the initial control strategy based on given voltage system is put forward. To further improve the performance of power system, a current feedback decoupling control strategy is proposed, and the mathematical model is established. The influence of full decoupled quadrature-direct (d-q axis currents is analyzed with respect to the output voltage adjusting time and fluctuation amplitude under the variations of piston displacement and output load. The simulation results show that the system performance is significantly improved, but the dynamic regulation lags caused by the decoupled current control still exist. To solve this problem and improve the performance of decoupled-state feedback current control that relies on parameter accuracy, internal model control based on sliding mode (IMC-SM current decoupling control strategy is proposed, the system model is established, and then the performance of voltage ripple in generating mode is improved. Finally, the test bench is built, and the steady state and transient voltage control performances are tested. The feasibility and priority of the control strategy is verified by experiment and simulation results.

  9. Frequency-Controlled Current-Fed Resonant Converter with No Input Ripple Current

    Directory of Open Access Journals (Sweden)

    Bor-Ren Lin

    2018-02-01

    Full Text Available This paper studies a frequency-controlled current-fed resonant circuit. The adopted direct current (DC-to-DC converter contains two boost circuits and a resonant circuit on the primary side. First, two boost circuits are connected in parallel to achieve voltage step-up and reduce input ripple current by using interleaved pulse-width modulation. Therefore, the size and current rating of boost inductors are decreased in the proposed converter. Second, the boost voltage is connected to the resonant circuit to realize the mechanism of the zero-voltage switching of all active switches and zero-current switching of all diodes. Two boost circuits and a resonant circuit use the same power devices in order to lessen the switch counts. The voltage doubler topology is adopted on the secondary side (high-voltage side. Therefore, the voltage rating of diodes on the high-voltage side is clamped at output voltage. The feasibility of the studied circuit is confirmed by the experimental tests with a 1 kW prototype circuit.

  10. Electric Machine with Boosted Inductance to Stabilize Current Control

    Science.gov (United States)

    Abel, Steve

    2013-01-01

    High-powered motors typically have very low resistance and inductance (R and L) in their windings. This makes the pulse-width modulated (PWM) control of the current very difficult, especially when the bus voltage (V) is high. These R and L values are dictated by the motor size, torque (Kt), and back-emf (Kb) constants. These constants are in turn set by the voltage and the actuation torque-speed requirements. This problem is often addressed by placing inductive chokes within the controller. This approach is undesirable in that space is taken and heat is added to the controller. By keeping the same motor frame, reducing the wire size, and placing a correspondingly larger number of turns in each slot, the resistance, inductance, torque constant, and back-emf constant are all increased. The increased inductance aids the current control but ruins the Kt and Kb selections. If, however, a fraction of the turns is moved from their "correct slot" to an "incorrect slot," the increased R and L values are retained, but the Kt and Kb values are restored to the desired values. This approach assumes that increased resistance is acceptable to a degree. In effect, the heat allocated to the added inductance has been moved from the controller to the motor body, which in some cases is preferred.

  11. Stator Current Harmonic Control with Resonant Controller for Doubly Fed Induction Generator

    DEFF Research Database (Denmark)

    Liu, Changjin; Blaabjerg, Frede; Chen, Wenjie

    2012-01-01

    rotor current control loop for harmonic suppression. The overall control scheme is implemented in dq frame. Based on a mathematical model of the DFIG control system, the effects on system stability using the resonant controller, an analysis of the steady-state error, and the dynamic performance......, are discussed in this paper. Taking these effects into account, the parameters of the resonant controller can be designed and effectively damp the influence from the grid voltage harmonics. As a result, the impacts of the negative sequence fifth- and positive sequence seventh-order voltage harmonics...... harmonics, especially low-order harmonics. This paper proposes a stator current harmonic suppression method using a sixth-order resonant controller to eliminate negative sequence fifth- and positive sequence seventh-order current harmonics. A stator current harmonic control loop is added to the conventional...

  12. Optimal Energy Control Strategy Design for a Hybrid Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Yuan Zou

    2013-01-01

    Full Text Available A heavy-duty parallel hybrid electric truck is modeled, and its optimal energy control is studied in this paper. The fundamental architecture of the parallel hybrid electric truck is modeled feed-forwardly, together with necessary dynamic features of subsystem or components. Dynamic programming (DP technique is adopted to find the optimal control strategy including the gear-shifting sequence and the power split between the engine and the motor subject to a battery SOC-sustaining constraint. Improved control rules are extracted from the DP-based control solution, forming near-optimal control strategies. Simulation results demonstrate that a significant improvement on the fuel economy can be achieved in the heavy-duty vehicle cycle from the natural driving statistics.

  13. Control Systems Cyber Security:Defense in Depth Strategies

    Energy Technology Data Exchange (ETDEWEB)

    David Kuipers; Mark Fabro

    2006-05-01

    Information infrastructures across many public and private domains share several common attributes regarding IT deployments and data communications. This is particularly true in the control systems domain. A majority of the systems use robust architectures to enhance business and reduce costs by increasing the integration of external, business, and control system networks. However, multi-network integration strategies often lead to vulnerabilities that greatly reduce the security of an organization, and can expose mission-critical control systems to cyber threats. This document provides guidance and direction for developing ‘defense-in-depth’ strategies for organizations that use control system networks while maintaining a multi-tier information architecture that requires: Maintenance of various field devices, telemetry collection, and/or industrial-level process systems Access to facilities via remote data link or modem Public facing services for customer or corporate operations A robust business environment that requires connections among the control system domain, the external Internet, and other peer organizations.

  14. Rotor Current Control of DFIG for Improving Fault Ride - Through Using a Novel Sliding Mode Control Approach

    Science.gov (United States)

    Cai, Guowei; Liu, Cheng; Yang, Deyou

    2013-11-01

    The doubly fed induction generators (DFIG) have been recognized as the dominant technology used in wind power generation systems with the rapid development of wind power. However, continuous operation of DFIG may cause a serious wind turbine generators tripping accident, due to destructive over-current in the rotor winding which is caused by the power system fault or inefficient fault ride-through (FRT) strategy. A new rotor current control scheme in the rotor-side converter (RSC) ispresented to enhance FRT capacities of grid-connected DFIG. Due to the strongly nonlinear nature of DFIG and insensitive to DFIG parameter's variations, a novel sliding mode controller was designed. The controller combines extended state observer (ESO) with sliding model variable structure control theory. The simulation is carried out to verify the effectiveness of the proposed control approach under various types of grid disturbances. It is shown that the proposed controller provides enhanced transient features than the classic proportional-integral control. The proposed control method can effectively reduce over-current in the RSC, and the transient pulse value of electromagnetic torque is too large under power grid fault.

  15. 40 CFR 93.120 - Consequences of control strategy implementation plan failures.

    Science.gov (United States)

    2010-07-01

    ... Consequences of control strategy implementation plan failures. (a) Disapprovals. (1) If EPA disapproves any submitted control strategy implementation plan revision (with or without a protective finding), the... is determined. (2) If EPA disapproves a submitted control strategy implementation plan revision...

  16. Cancer pain and current theory for pain control.

    Science.gov (United States)

    Kahan, Brian

    2014-05-01

    This article discusses current trends in managing cancer pain, with specific regard to opioid transmission, descending pathway inhabitation, and ways to facilitate the endogenous antinociceptive chemicals in the human body. Various techniques for opioid and nonopioid control of potential pain situations of patients with cancer are discussed. The benefits of using pharmacogenetics to assess the appropriate medications are addressed. Finally, specific treatment of abdominal cancer pain using radiofrequency lesioning is discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Controlling the emission current from a plasma cathode

    International Nuclear Information System (INIS)

    Bagaev, S.P.; Gushenets, V.I.; Schanin, P.M.

    1993-01-01

    The processes determining the time and amplitude characteristics of the grid-controlled electron emission from the plasma of an arc discharge have been analyzed. It has been shown that by applying to the grid confining the plasma emission boundary of a modulated voltage it is possible to form current pulse of up to 1 kA with nanosecond risetimes and falltimes and a pulse repetitive rate of 100 kHz

  18. Direct harmonic voltage control strategy for shunt active power filter

    DEFF Research Database (Denmark)

    Munir, Hafiz Mudassir; Zou, JianXiao; Xie, Chuan

    2017-01-01

    generation system (DPGS) where the nonlinear loads are highly dispersed. Local harmonic voltage detection based Resistive-APF (R-APF) seems more suitable to be applied in the DPGS, however, R-APF suffers from poor compensation performance and difficulty of parameter tuning. In this paper, a direct harmonic...... voltage control strategy for the S-APF is proposed with local point of common coupling (PCC) voltage detection only. The control strategy design procedure is given in detail. Simulation is conducted in Matlab/Simulink to compare the performance between the R-APF and the proposed method. The results...

  19. Shear optimization experiments with current profile control on JET

    International Nuclear Information System (INIS)

    1997-01-01

    A record performance on JET has been obtained with shear optimization scenarios. A neutron yield of 5.6x10 16 s -1 in deuterium discharges, and a global energy confinement improvement above the ITER-89 L-mode scaling with H ≤ 2.5 in L-mode and H ≤ 3 in H-mode have been achieved. The tailoring of plasma current, density and heating power waveforms and current profile control with lower hybrid current drive and ICRF phasing have been essential. Internal energy, particle and momentum transport barriers develop spontaneously upon heating above a threshold power of about 15 MW with neutral beams and ICRH into a low-density target plasma, with a wide central region of slightly negative or flat magnetic shear with q > 1 everywhere. An additional H-mode transition can also raise the pressure in the region between internal and edge transport barriers. The ion heat conductivity falls to the neoclassical level in the improved core confinement region. Pressure profile control through power deposition feedback control makes it possible to work close to the marginal stability boundary for pressure-driven MHD modes. First experiments in deuterium/tritium plasmas, with up to 75% tritium target concentration, have established internal transport barriers already with heating powers at the lowest threshold of pure deuterium plasmas, resulting in a fusion power output of P fusion = 2 MW. (author)

  20. Current standards for infection control: audit assures compliance.

    Science.gov (United States)

    Flanagan, Pauline

    Having robust policies and procedures in place for infection control is fundamentally important. However, each organization has to go a step beyond this; evidence has to be provided that these policies and procedures are followed. As of 1 April 2009, with the introduction of the Care Quality Commission and The Health and Social Care Act 2008 Code of Practice for the NHS on the Prevention and Control of Healthcare-Associated Infections and Related Guidance, the assurance of robust infection control measures within any UK provider of health care became an even higher priority. Also, the commissioning of any service by the NHS must provide evidence that the provider has in place robust procedures for infection control. This article demonstrates how the clinical audit team at the Douglas Macmillan Hospice in North Staffordshire, UK, have used audit to assure high rates of compliance with the current national standards for infection control. Prior to the audit, hospice staff had assumed that the rates of compliance for infection control approached 100%. This article shows that a good quality audit tool can be used to identify areas of shortfall in infection control and the effectiveness of putting in place an action plan followed by re-audit.

  1. Analysis of Control Strategies for Aircraft Flight Upset Recovery

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.; Cox, David E.; Muri, Daniel G.

    2012-01-01

    This paper proposes a framework for studying the ability of a control strategy, consisting of a control law and a command law, to recover an aircraft from ight conditions that may extend beyond the normal ight envelope. This study was carried out (i) by evaluating time responses of particular ight upsets, (ii) by evaluating local stability over an equilibrium manifold that included stall, and (iii) by bounding the set in the state space from where the vehicle can be safely own to wings-level ight. These states comprise what will be called the safely recoverable ight envelope (SRFE), which is a set containing the aircraft states from where a control strategy can safely stabilize the aircraft. By safe recovery it is implied that the tran- sient response stays between prescribed limits before converging to a steady horizontal ight. The calculation of the SRFE bounds yields the worst-case initial state corresponding to each control strategy. This information is used to compare alternative recovery strategies, determine their strengths and limitations, and identify the most e ective strategy. In regard to the control law, the authors developed feedback feedforward laws based on the gain scheduling of multivariable controllers. In regard to the command law, which is the mechanism governing the exogenous signals driving the feed- forward component of the controller, we developed laws with a feedback structure that combines local stability and transient response considera- tions. The upset recovery of the Generic Transport Model, a sub-scale twin-engine jet vehicle developed by NASA Langley Research Center, is used as a case study.

  2. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Science.gov (United States)

    Leng, Min-Rui; Zhou, Guo-Hua; Zhang, Kai-Tun; Li, Zhen-Hua

    2015-10-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. Project supported by the National Natural Science Foundation of China (Grant No. 61371033), the Fok Ying-Tung Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 142027), the Sichuan Provincial Youth Science and Technology Fund, China (Grant Nos. 2014JQ0015 and 2013JQ0033), and the Fundamental Research Funds for the Central Universities, China (Grant No. SWJTU11CX029).

  3. Late-life suicide prevention strategies: current status and future directions.

    Science.gov (United States)

    Van Orden, Kim; Deming, Charlene

    2017-09-08

    Late life suicide prevention differs from suicide prevention for other age groups: first, the number of older adults worldwide is on the rise; second, late-life suicide receives much less attention in all societal spheres, from the media, to federal funding agencies, to healthcare initiatives. Recent findings indicate an association between internalized ageist stereotypes and reduced will to live. Recent research also addresses the role of cognitive control as a contributor to risk and as an intervention target (e.g., through psychotherapies such as problem solving therapy) as well as firearm safety as a promising, though a politicized and challenging strategy to implement. Another strategy that may prove feasible is an approach on upstream prevention strategies in healthcare. One strategy we believe holds great promise is the promotion of high quality geriatric medicine. Geriatricians are trained to work with patients to prioritize the promotion of physical and cognitive functioning (rather than solely absence of disease) and to focus on well-being as a goal. Thus, geriatricians routinely target numerous late-life suicide risk factors-physical illness, functioning, pain, and (dis)satisfaction with life. However, efficacious strategies will not prevent suicide deaths if they are not implemented-addressing ageism as a universal prevention strategy is essential. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Strategies of bringing drug product marketing applications to meet current regulatory standards.

    Science.gov (United States)

    Wu, Yan; Freed, Anita; Lavrich, David; Raghavachari, Ramesh; Huynh-Ba, Kim; Shah, Ketan; Alasandro, Mark

    2015-08-01

    In the past decade, many guidance documents have been issued through collaboration of global organizations and regulatory authorities. Most of these are applicable to new products, but there is a risk that currently marketed products will not meet the new compliance standards during audits and inspections while companies continue to make changes through the product life cycle for continuous improvement or market demands. This discussion presents different strategies to bringing drug product marketing applications to meet current and emerging standards. It also discusses stability and method designs to meet process validation and global development efforts.

  5. Current challenges and emerging drug delivery strategies for the treatment of psoriasis.

    Science.gov (United States)

    Hoffman, Melissa B; Hill, Dane; Feldman, Steven R

    2016-10-01

    Psoriasis is a common skin disorder associated with physical, social, psychological and financial burden. Over the past two decades, advances in our understanding of pathogenesis and increased appreciation for the multifaceted burden of psoriasis has led to new treatment development and better patient outcomes. Yet, surveys demonstrate that many psoriasis patients are either undertreated or are dissatisfied with treatment. There are many barriers that need be overcome to optimize patient outcomes and satisfaction. This review covers the current challenges associated with each major psoriasis treatment strategy (topical, phototherapy, oral medications and biologics). It also reviews the challenges associated with the psychosocial aspects of the disease and how they affect treatment outcomes. Patient adherence, inconvenience, high costs, and drug toxicities are all discussed. Then, we review the emerging drug delivery strategies in topical, oral, and biologic therapy. By outlining current treatment challenges and emerging drug delivery strategies, we hope to highlight the deficits in psoriasis treatment and strategies for how to overcome them. Regardless of disease severity, clinicians should use a patient-centered approach. In all cases, we need to balance patients' psychosocial needs, treatment costs, convenience, and effectiveness with patients' preferences in order to optimize treatment outcomes.

  6. A real-time current driving control system for the TJ-II coils

    International Nuclear Information System (INIS)

    Pena, Angel de la; Pacios, Luis; Carrasco, Ricardo; Lapayese, Fernando

    2009-01-01

    Since the start of plasma operation in the TJ-II stellarator, the required values of DC currents that are fed to its different coil sets have been controlled to high precision along the complete discharge flat-top. As a result each current configuration produced a highly stable magnetic-field configuration. Recently, the configurational flexibility of the TJ-II has been broadened by the commissioning of a new mode of operation that allows magnetic configurations to be varied dynamically during the discharge flat-top. In order to achieve this, new hardware and software features have been added to the TJ-II Control System. These new features may also provide new strategies for feedback control in accordance with parameters measured in one or more diagnostics. In this new set-up, coil current profiles are generated and controlled to millisecond timescales by a system based on VMEbus and OS9 real-time operating system. A new communication middleware architecture called XML-based Messages Distribution Service (X-MDS) has been designed to exchange XML-based data with calling clients. Furthermore, with this software, a fully functional Java application for supervision and for current profiles settings has been developed. This paper provides a detailed description of the complete TJ-II real-time current-profile control system and results obtained during its operation.

  7. A real-time current driving control system for the TJ-II coils

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Angel de la [Association EURATOM - CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain)], E-mail: a.delapena@ciemat.es; Pacios, Luis; Carrasco, Ricardo; Lapayese, Fernando [Association EURATOM - CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain)

    2009-06-15

    Since the start of plasma operation in the TJ-II stellarator, the required values of DC currents that are fed to its different coil sets have been controlled to high precision along the complete discharge flat-top. As a result each current configuration produced a highly stable magnetic-field configuration. Recently, the configurational flexibility of the TJ-II has been broadened by the commissioning of a new mode of operation that allows magnetic configurations to be varied dynamically during the discharge flat-top. In order to achieve this, new hardware and software features have been added to the TJ-II Control System. These new features may also provide new strategies for feedback control in accordance with parameters measured in one or more diagnostics. In this new set-up, coil current profiles are generated and controlled to millisecond timescales by a system based on VMEbus and OS9 real-time operating system. A new communication middleware architecture called XML-based Messages Distribution Service (X-MDS) has been designed to exchange XML-based data with calling clients. Furthermore, with this software, a fully functional Java application for supervision and for current profiles settings has been developed. This paper provides a detailed description of the complete TJ-II real-time current-profile control system and results obtained during its operation.

  8. Prevention and control of schistosomiasis: a current perspective

    Directory of Open Access Journals (Sweden)

    Inobaya MT

    2014-10-01

    Full Text Available Marianette T Inobaya,1 Remigio M Olveda,1 Thao NP Chau,3 David U Olveda,2 Allen GP Ross21Department of Health, Research Institute for Tropical Medicine, Muntinlupa City, Philippines; 2Griffith Health Institute, School of Medical Sciences, Gold Coast Campus, Griffith University, Southport, Australia; 3Discipline of Public Health, Flinders University, Adelaide, AustraliaAbstract: Schistosomiasis is a neglected tropical disease that ranks second only to malaria in terms of human suffering in the tropics and subtropics. Five species are known to infect man and there are currently over 240 million people infected worldwide. The cornerstone of control to date has been mass drug administration with 40 mg/kg of praziquantel but there are problems with this approach. Human and bovine vaccines are in various stages of development. Integrated control, targeting the life cycle, is the only approach that will lead to sustainability and future elimination.Keywords: schistosomiais, morbidity, treatment and control, mass drug administration

  9. An Efficient Modal Control Strategy for the Active Vibration Control of a Truss Structure

    Directory of Open Access Journals (Sweden)

    Ricardo Carvalhal

    2007-01-01

    Full Text Available In this paper an efficient modal control strategy is described for the active vibration control of a truss structure. In this approach, a feedback force is applied to each mode to be controlled according to a weighting factor that is determined by assessing how much each mode is excited by the primary source. The strategy is effective provided that the primary source is at a fixed position on the structure, and that the source is stationary in the statistical sense. To test the effectiveness of the control strategy it is compared with an alternative, established approach namely, Independent Modal Space Control (IMSC. Numerical simulations show that with the new strategy it is possible to significantly reduce the control effort required, with a minimal reduction in control performance.

  10. Effects of Flood Control Strategies on Flood Resilience Under Sociohydrological Disturbances

    Science.gov (United States)

    Sung, Kyungmin; Jeong, Hanseok; Sangwan, Nikhil; Yu, David J.

    2018-04-01

    A community capacity to cope with flood hazards, or community flood resilience, emerges from the interplay of hydrological and social processes. This interplay can be significantly influenced by the flood control strategy adopted by a society, i.e., how a society sets its desired flood protection level and strives to achieve this goal. And this interplay can be further complicated by rising land-sea level differences, seasonal water level fluctuations, and economic change. But not much research has been done on how various forms of flood control strategies affect human-flood interactions under these disturbances and therefore flood resilience in the long run. The current study is an effort to address these issues by developing a conceptual model of human-flood interaction mediated by flood control strategies. Our model extends the existing model of Yu et al. (2017), who investigated the flood resilience of a community-based flood protection system in coastal Bangladesh. The major extensions made in this study are inclusions of various forms of flood control strategies (both adaptive and nonadaptive ones), the challenge of rising land-sea level differences, and various high tide level scenarios generated from modifying the statistical variances and averages. Our results show that adaptive forms of flood control strategies tend to outperform nonadaptive ones for maintaining the model community's flood protection system. Adaptive strategies that dynamically adjust target flood protection levels through close monitoring of flood damages and social memories of flood risk can help the model community deal with various disturbances.

  11. Chaos Control on a Duopoly Game with Homogeneous Strategy

    Directory of Open Access Journals (Sweden)

    Manying Bai

    2016-01-01

    Full Text Available We study the dynamics of a nonlinear discrete-time duopoly game, where the players have homogenous knowledge on the market demand and decide their outputs based on adaptive expectation. The Nash equilibrium and its local stability are investigated. The numerical simulation results show that the model may exhibit chaotic phenomena. Quasiperiodicity is also found by setting the parameters at specific values. The system can be stabilized to a stable state by using delayed feedback control method. The discussion of control strategy shows that the effect of both firms taking control method is better than that of single firm taking control method.

  12. Sensor-Based Model Driven Control Strategy for Precision Irrigation

    Directory of Open Access Journals (Sweden)

    Camilo Lozoya

    2016-01-01

    Full Text Available Improving the efficiency of the agricultural irrigation systems substantially contributes to sustainable water management. This improvement can be achieved through an automated irrigation system that includes a real-time control strategy based on the water, soil, and crop relationship. This paper presents a model driven control strategy applied to an irrigation system, in order to make an efficient use of water for large crop fields, that is, applying the correct amount of water in the correct place at the right moment. The proposed model uses a predictive algorithm that senses soil moisture and weather variables, to determine optimal amount of water required by the crop. This proposed approach is evaluated against a traditional irrigation system based on the empirical definition of time periods and against a basic soil moisture control system. Results indicate that the use of a model predictive control in an irrigation system achieves a higher efficiency and significantly reduce the water consumption.

  13. Comparison of different control strategies on FMD in Denmark

    DEFF Research Database (Denmark)

    Boklund, Anette; Hisham Beshara Halasa, Tariq; Christiansen, Lasse Engbo

    2012-01-01

    The purpose of this study was to compare different control strategies that could be used in Denmark during an outbreak of FMD, based on epidemiological, ethical and economic parameters. Nearly a hundred different control strategies and more than 30 sensitivity analyses were run, changing between...... to extract the essence of the results. All results will be presented in the final project report, which will be available on request to the authors. Comparing epidemiological outputs showed that extra control measures will always reduce the average duration and size of an epidemic. However, the variations...... in duration and size of epidemics are large, and if epidemics are small, extra control measures may not always be necessary. Comparing depopulation to suppressive and protective vaccination shows that from an epidemiologic point of view, vaccination will be beneficial. However, comparing the economy...

  14. Optimal Control Strategy Search Using a Simplest 3-D PWR Xenon Oscillation Simulator

    International Nuclear Information System (INIS)

    Yoichiro, Shimazu

    2004-01-01

    Power spatial oscillations due to the transient xenon spatial distribution are well known as xenon oscillation in large PWRs. When the reactor size becomes larger than the current design, then even radial oscillations can be also divergent. Even if the radial oscillation is convergent, when some control rods malfunction occurs, it is necessary to suppress the oscillation in as short time as possible. In such cases, optimal control strategy is required. Generally speaking the optimality search based on the modern control theory requires a lot of calculation for the evaluation of state variables. In the case of control rod malfunctions the xenon oscillation could be three dimensional. In such case, direct core calculations would be inevitable. From this point of view a very simple model, only four point reactor model, has been developed and verified. In this paper, an example of a procedure and the results for optimal control strategy search are presented. It is shown that we have only one optimal strategy within a half cycle of the oscillation with fixed control strength. It is also shown that a 3-D xenon oscillation introduced by a control rod malfunction can not be controlled by only one control step as can be done for axial oscillations. They might be quite strong limitations to the operators. Thus it is recommended that a strategy generator, which is quick in analyzing and easy to use, might be installed in a monitoring system or operator guiding system. (author)

  15. Control strategies used in the control software for the Heavy Ion Research Facility in Lanzhou

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wen-Xiong [College of Power Engineering, Chongqing University, Chongqing 400044 (China); Postdoctoral Station, Chongqing University, Chongqing 400044 (China); Wang, Yan-Yu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pan, Liang-Ming [College of Power Engineering, Chongqing University, Chongqing 400044 (China); Tu, Sheng-Pan [State Grid Chongqing Maintenance Company, Chongqing 400044 (China)

    2016-07-01

    Automation control systems are important for the operation of an accelerator. To ensure the reliable, stable and flexible operation of the Heavy Ion Research Facility in Lanzhou (HIRFL), several control systems are developed. The developed control systems are the SECRAL control system, the LECR3 control system, the LAPECR1 control system and the Electro-Static septum control system. The corresponding control software systems are developed using Visual C++. To ensure the accuracy, stability and flexibility of the control systems, some special control strategies are developed in the control software systems. This paper provides a detailed description of the main control strategies used in the control software systems. The main control strategies are composed of a reliable communication mechanism, a correct data/command transmission mechanism, an efficient data storage mechanism and an interlock protection mechanism. To guarantee a reliable communication between the devices for the commercially purchased devices and the built in-house ones, a modified heartbeat method is developed. To provide flexible reconstitution function for the control systems, the command queue and the state machine are combined. The message mechanism and the multiple windows mechanism are also used for the module mechanism. The relevant control systems are introduced as examples of these control strategies. These systems have been running stably for several years.

  16. Control strategies used in the control software for the Heavy Ion Research Facility in Lanzhou

    International Nuclear Information System (INIS)

    Zhou, Wen-Xiong; Wang, Yan-Yu; Pan, Liang-Ming; Tu, Sheng-Pan

    2016-01-01

    Automation control systems are important for the operation of an accelerator. To ensure the reliable, stable and flexible operation of the Heavy Ion Research Facility in Lanzhou (HIRFL), several control systems are developed. The developed control systems are the SECRAL control system, the LECR3 control system, the LAPECR1 control system and the Electro-Static septum control system. The corresponding control software systems are developed using Visual C++. To ensure the accuracy, stability and flexibility of the control systems, some special control strategies are developed in the control software systems. This paper provides a detailed description of the main control strategies used in the control software systems. The main control strategies are composed of a reliable communication mechanism, a correct data/command transmission mechanism, an efficient data storage mechanism and an interlock protection mechanism. To guarantee a reliable communication between the devices for the commercially purchased devices and the built in-house ones, a modified heartbeat method is developed. To provide flexible reconstitution function for the control systems, the command queue and the state machine are combined. The message mechanism and the multiple windows mechanism are also used for the module mechanism. The relevant control systems are introduced as examples of these control strategies. These systems have been running stably for several years.

  17. Control strategy research of two stage topology for pulsed power supply

    International Nuclear Information System (INIS)

    Shi Chunfeng; Wang Rongkun; Huang Yuzhen; Chen Youxin; Yan Hongbin; Gao Daqing

    2013-01-01

    A kind of pulsed power supply of HIRFL-CSR was introduced, the ripple and the current error of the topological structure of the power in the operation process were analyzed, and two stage topology of pulsed power supply was given. The control strategy was simulated and the experiment was done in digital power platform. The results show that the main circuit structure and control method are feasible. (authors)

  18. Modelling the transport system in China and evaluating the current strategies towards the sustainable transport development

    International Nuclear Information System (INIS)

    Liu, Wen; Lund, Henrik; Mathiesen, Brian Vad

    2013-01-01

    Transport is one of the most challenge sectors when addressing energy security and climate change due to its high reliance on oil products and lack of the alternative fuels. This paper explores the ability of three transport strategies to contribute to the development of a sustainable transport in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13% of the energy saving and 12% of the CO 2 emission reduction can be attained by accomplishing three strategies compared with the reference transport system. However, the energy demand of transport in 2020 with the implementation of three strategies will be about 1.7 times as much as today. The three strategies show the potential of drawing the transport demand to the more energy efficient vehicles; however, more initiatives are needed if the sustainable transport is the long term objective, such as the solutions to stabilise the private vehicle demands, to continuously improve the vehicle efficiency and to boost the alternative fuels produced from the renewable energy sources. - Highlights: • A Chinese transport model was created and three transport strategies were evaluated • Transport is the biggest driver of the oil demand in China not the industry • The energy demand of transport in 2020 will be twice as much as today • Strategies contribute 13% energy saving and 12% CO 2 emission reduction • More initiatives are needed if a sustainable transport is the long-term objective

  19. A fault tolerant superheat control strategy for supermarket refrigeration systems

    DEFF Research Database (Denmark)

    Vinther, Kasper; Izadi-Zamanabadi, Roozbeh; Rasmussen, Henrik

    2013-01-01

    , based on a maximum slope-seeking control method and only a single temperature sensor, is developed to drive the evaporator outlet temperature to a level that gives a suitable superheat of the refrigerant. The FTC strategy requires no a priori system knowledge or additional hardware and functions...

  20. Benchmarking of Control Strategies for Wastewater Treatment Plants

    DEFF Research Database (Denmark)

    Wastewater treatment plants are large non-linear systems subject to large perturbations in wastewater flow rate, load and composition. Nevertheless these plants have to be operated continuously, meeting stricter and stricter regulations. Many control strategies have been proposed in the literature...

  1. Modeling an impact control strategy using HyPA

    NARCIS (Netherlands)

    Cuijpers, P.J.L.; Reniers, M.A.; Cassandras, C.G.; Giua, A.; Seatzu, C.; Zaytoon, J.

    2006-01-01

    We analyze a control strategy for the pick-and-place module of a component mounting device.We use a combination of techniques from bondgraph-theory, systems theory, process algebra and differential algebra to achieve this, and we show how the hybrid process algebra HyPA aides us in combining these

  2. Control strategies for laser separation of carbon isotopes

    Indian Academy of Sciences (India)

    Unknown

    Control strategies for laser separation of carbon isotopes. V PARTHASARATHY*, A K ... The emerging market for medical applications of C-13 is projected to be in the range of hundreds of ..... thermal effects during irradiation. In the absence of ...

  3. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1676 Section 52.1676 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347...

  4. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1876 Section 52.1876 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan...

  5. Electric Water Heater Modeling and Control Strategies for Demand Response

    Energy Technology Data Exchange (ETDEWEB)

    Diao, Ruisheng; Lu, Shuai; Elizondo, Marcelo A.; Mayhorn, Ebony T.; Zhang, Yu; Samaan, Nader A.

    2012-07-22

    Abstract— Demand response (DR) has a great potential to provide balancing services at normal operating conditions and emergency support when a power system is subject to disturbances. Effective control strategies can significantly relieve the balancing burden of conventional generators and reduce investment on generation and transmission expansion. This paper is aimed at modeling electric water heaters (EWH) in households and tests their response to control strategies to implement DR. The open-loop response of EWH to a centralized signal is studied by adjusting temperature settings to provide regulation services; and two types of decentralized controllers are tested to provide frequency support following generator trips. EWH models are included in a simulation platform in DIgSILENT to perform electromechanical simulation, which contains 147 households in a distribution feeder. Simulation results show the dependence of EWH response on water heater usage . These results provide insight suggestions on the need of control strategies to achieve better performance for demand response implementation. Index Terms— Centralized control, decentralized control, demand response, electrical water heater, smart grid

  6. Precision electronic speed controller for an alternating-current motor

    Science.gov (United States)

    Bolie, V.W.

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. The motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The speed error signal is generated by a novel vernier-logic circuit which is drift-free and highly sensitive to small speed changes. The phase error is also computed by digital logic, with adjustable sensitivity around a 0 mid-scale value. The drift error signal, generated by long-term counting of the phase error, is used to compensate for any slow changes in the average friction drag on the motor. An auxillary drift-byte status sensor prevents any disruptive overflow or underflow of the drift-error counter. An adjustable clocked-delay unit is inserted between the controller and the source of the reference pulse train to permit phase alignment of the rotor to any desired offset angle. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of read-only memories, and a pair of digital-to-analog converters.

  7. Emerging trends in vibration control of wind turbines: a focus on a dual control strategy.

    Science.gov (United States)

    Staino, Andrea; Basu, Biswajit

    2015-02-28

    The paper discusses some of the recent developments in vibration control strategies for wind turbines, and in this context proposes a new dual control strategy based on the combination and modification of two recently proposed control schemes. Emerging trends in the vibration control of both onshore and offshore wind turbines are presented. Passive, active and semi-active structural vibration control algorithms have been reviewed. Of the existing controllers, two control schemes, active pitch control and active tendon control, have been discussed in detail. The proposed new control scheme is a merger of active tendon control with passive pitch control, and is designed using a Pareto-optimal problem formulation. This combination of controllers is the cornerstone of a dual strategy with the feature of decoupling vibration control from optimal power control as one of its main advantages, in addition to reducing the burden on the pitch demand. This dual control strategy will bring in major benefits to the design of modern wind turbines and is expected to play a significant role in the advancement of offshore wind turbine technologies. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Robust predictive control strategy applied for propofol dosing using BIS as a controlled variable during anesthesia

    NARCIS (Netherlands)

    Ionescu, Clara A.; De Keyser, Robin; Torrico, Bismark Claure; De Smet, Tom; Struys, Michel M. R. F.; Normey-Rico, Julio E.

    This paper presents the application of predictive control to drug dosing during anesthesia in patients undergoing surgery. The performance of a generic predictive control strategy in drug dosing control, with a previously reported anesthesia-specific control algorithm, has been evaluated. The

  9. A multi-objective control strategy for grid connection of DG (distributed generation) resources

    Energy Technology Data Exchange (ETDEWEB)

    Pouresmaeil, Edris; Montesinos-Miracle, Daniel; Bergas-Jane, Joan [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Departament d' Enginyeria Electrica, Universitat Politecnica de Catalunya, ETS d' Enginyeria Industrial de Barcelona (Spain); Gomis-Bellmunt, Oriol [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Departament d' Enginyeria Electrica, Universitat Politecnica de Catalunya, ETS d' Enginyeria Industrial de Barcelona (Spain); Catalonia Institute for Energy Research IREC, Barcelona (Spain)

    2010-12-15

    This paper presents a flexible control technique for connection of DG (distributed generation) resources to distribution networks, especially during ride-through on faulty grid. This strategy is derived from the abc/{alpha}{beta} and {alpha}{beta}/dq transformations of the ac system variables. The active and reactive currents injected by the DG source are controlled in the synchronously rotating orthogonal dq reference frame. The transformed variables are used to control the VSI (voltage source inverter) which connects the DG to the distribution network. Using a P.L.L. (phase locked loop) in circuit of proposed control technique, the angle of positive sequence has been detected, in order to synchronize the currents to the distribution network. The proposed control technique has the capability of providing active and reactive powers and harmonic currents to nonlinear loads with a fast dynamic response. Simulation results and mathematical analysis have been completed in order to achieve a reduced THD (total harmonic distortion), increased power factor and compensated load's active and reactive powers. The analyses show the high performance of this control strategy in DG applications in comparison with other existing strategies. (author)

  10. Automatic control system for measuring currents produced by ionization chambers

    International Nuclear Information System (INIS)

    Brancaccio, Franco

    2002-01-01

    Ionization Chambers in current mode operation are usually used in Nuclear Metrology. Activity measurements are quickly performed by Ionization Chambers, with very good precision. For this purpose measurements of very low ionization currents, carried out by high quality instrumentation, are required. Usually, electrometers perform the current integration method under command of signals from an automation system, in order to reduce the measurement uncertainties. Among the measurement systems at the Laboratorio de Metrologia Nuclear (LMN) of IPEN, there are two ionization chamber systems. In the present work, an automation system developed for current integration measurements is described. This automation system is composed by software (graphic interface and control) and an electronic module connected to a microcomputer, by means of a commercial data acquisition card. Several test measurements were performed in order to determine the intrinsic uncertainty, linearity and stability of the system. Using calibrated radioactive solutions, the IG12/A20 chamber calibration factors for 18 F and 153 Sm were obtained, making possible to determine activities of these radionuclides. (author)

  11. Transgenesis and paratransgenesis to control insect-borne diseases: Current status and future challenges

    Science.gov (United States)

    Coutinho-Abreu, Iliano V.; Zhu, Kun Yan; Ramalho-Ortigao, Marcelo

    2009-01-01

    Insect-borne diseases cause significant human morbidity and mortality. Current control and preventive methods against vector-borne diseases rely mainly on insecticides. The emergence of insecticide resistance in many disease vectors highlights the necessity to develop new strategies to control these insects. Vector transgenesis and paratransgenesis are novel strategies that aim at reducing insect vectorial capacity, or seek to eliminate transmission of pathogens such as Plasmodium sp., Trypanosoma sp., and Dengue virus currently being developed. Vector transgenesis relies on direct genetic manipulation of disease vectors making them incapable of functioning as vectors of a given pathogen. Paratransgenesis focuses on utilizing genetically modified insect symbionts to express molecules within the vector that are deleterious to pathogens they transmit. Despite the many successes achieved in developing such techniques in the last several years, many significant barriers remain and need to be overcome prior to any of these approaches become a reality. Here, we highlight the current status of these strategies, pointing out advantages and constraints, and also explore issues that need to be resolved before the establishment of transgenesis and paratransgenesis as tools to prevent vector-borne diseases. PMID:19819346

  12. A simplified controller and detailed dynamics of constant off-time peak current control

    Science.gov (United States)

    Van den Bossche, Alex; Dimitrova, Ekaterina; Valchev, Vencislav; Feradov, Firgan

    2017-09-01

    A fast and reliable current control is often the base of power electronic converters. The traditional constant frequency peak control is unstable above 50 % duty ratio. In contrast, the constant off-time peak current control (COTCC) is unconditionally stable and fast, so it is worth analyzing it. Another feature of the COTCC is that one can combine a current control together with a current protection. The time dynamics show a zero-transient response, even when the inductor changes in a wide range. It can also be modeled as a special transfer function for all frequencies. The article shows also that it can be implemented in a simple analog circuit using a wide temperature range IC, such as the LM2903, which is compatible with PV conversion and automotive temperature range. Experiments are done using a 3 kW step-up converter. A drawback is still that the principle does not easily fit in usual digital controllers up to now.

  13. Two coupled Josephson junctions: dc voltage controlled by biharmonic current

    International Nuclear Information System (INIS)

    Machura, L; Spiechowicz, J; Kostur, M; Łuczka, J

    2012-01-01

    We study transport properties of two Josephson junctions coupled by an external shunt resistance. One of the junctions (say, the first) is driven by an unbiased ac current consisting of two harmonics. The device can rectify the ac current yielding a dc voltage across the first junction. For some values of coupling strength, controlled by an external shunt resistance, a dc voltage across the second junction can be generated. By variation of system parameters such as the relative phase or frequency of two harmonics, one can conveniently manipulate both voltages with high efficiency, e.g. changing the dc voltages across the first and second junctions from positive to negative values and vice versa. (paper)

  14. Diagnostic development for current density profile control at KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J., E-mail: jinseok@nfri.re.kr [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); University of Science and Technology, Daejeon 34113 (Korea, Republic of); Chung, J. [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Messmer, M.C.C. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven (Netherlands)

    2016-11-01

    Highlights: • The motional Stark effect (MSE) diagnostic installed at KSTAR. • Engineering challenges and solutions on the design and fabrication of the front optics housing and filter modules. • Characterization of the bandpass filters and the responses to polarized light. - Abstract: The current density profile diagnostics are critical for the control of the steady-state burning plasma operations. A multi-channel motional Stark effect (MSE) diagnostic system has been implemented for the measurements of the internal magnetic field structures that constrain the magnetic equilibrium reconstruction to accurately produce the tokamak safety factor and current density profiles for the Korea Superconducting Tokamak Advanced Research (KSTAR). This work presents the design and fabrication of the front optics and the filter modules and the calibration activities for the MSE diagnostic at KSTAR.

  15. Rapid Detection Strategies for the Global Threat of Zika Virus: Current State, New Hypotheses and Limitations

    Directory of Open Access Journals (Sweden)

    Shruti Shukla

    2016-10-01

    Full Text Available The current scenario regarding the widespread Zika virus (ZIKV has resulted in numerous diagnostic studies, specifically in South America and in locations where there is frequent entry of travelers returning from ZIKV-affected areas, including pregnant women with or without clinical symptoms of ZIKV infection. The World Health Organization, WHO, announced that millions of cases of ZIKV are likely to occur in the United States of America in the near future. This situation has created an alarming public health emergency of international concern requiring the detection of this life-threatening viral candidate due to increased cases of newborn microcephaly associated with ZIKV infection. Hence, this review reports possible methods and strategies for the fast and reliable detection of ZIKV with particular emphasis on current updates, knowledge and new hypotheses that might be helpful for medical professionals in poor and developing countries that urgently need to address this problem. In particular, we emphasize liposome-based biosensors. Although these biosensors are currently among the less popular tools for human disease detection, they have become useful tools for the screening and detection of pathogenic bacteria, fungi and viruses because of their versatile advantageous features compared to other sensing devices. This review summarizes the currently available methods employed for the rapid detection of ZIKV and suggests an innovative approach involving the application of a liposome-based hypothesis for the development of new strategies for ZIKV detection and their use as effective biomedicinal tools.

  16. Economic implications of three strategies for the control of taeniasis.

    Science.gov (United States)

    Alexander, Anu; John, K R; Jayaraman, T; Oommen, Anna; Venkata Raghava, M; Dorny, Pierre; Rajshekhar, Vedantam

    2011-11-01

    To evaluate the cost-effectiveness of three strategies for the control of taeniasis in a community, in terms of cost per case treated. A study was conducted in South India to determine the prevalence of taeniasis by screening stool samples from 653 randomly chosen subjects, for coproantigens. The costs incurred in the project were used to estimate the cost per case screened and treated. A one-way sensitivity analysis was carried out for varying rates of taeniasis, different screening strategies and mass therapy. Further sensitivity analysis was carried out with different manpower and test costs. The rate of taeniasis as detected by ELISA for coproantigen was 3 per 1000 (2 of 653 samples). Our study showed that mass therapy without screening for taeniasis would be the most economical strategy in terms of cost per case treated if field workers are employed exclusively for either mass therapy or screening. For each strategy, costs per case treated are higher at low prevalence of taeniasis, with a sharp rise below 15%. In places that are endemic for taeniasis and neurocysticercosis, mass therapy or screening for taeniasis should be considered. Screening by stool microscopy is not cost-effective in terms of cost per case of taeniasis treated owing to its low sensitivity. Although the cost per case of taeniasis treated is high at low prevalence of taeniasis for all options, incorporating mass therapy into existing mass drug distribution programmes might prove to be the most cost-effective control strategy. © 2011 Blackwell Publishing Ltd.

  17. Hierarchical Controlled Grid-Connected Microgrid based on a Novel Autonomous Current Sharing Controller

    DEFF Research Database (Denmark)

    Guan, Yajuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    In this paper, a hierarchical control system based on a novel autonomous current sharing controller for grid-connected microgrids (MGs) is presented. A three-level hierarchical control system is implemented to guarantee the power sharing performance among voltage controlled parallel inverters......, while providing the required active and reactive power to the utility grid. A communication link is used to transmit the control signal from the tertiary and secondary control levels to the primary control. Simulation results from a MG based on two grid-connected parallel inverters are shown in order...

  18. Current-Loop Control for the Pitching Axis of Aerial Cameras via an Improved ADRC

    Directory of Open Access Journals (Sweden)

    BingYou Liu

    2017-01-01

    Full Text Available An improved active disturbance rejection controller (ADRC is designed to eliminate the influences of the current-loop for the pitching axis control system of an aerial camera. The improved ADRC is composed of a tracking differentiator (TD, an improved extended state observer (ESO, an improved nonlinear state error feedback (NLSEF, and a disturbance compensation device (DCD. The TD is used to arrange transient process. The improved ESO is utilized to observe the state extended by nonlinear dynamics, model uncertainty, and external disturbances. Overtime variation of the current-loop can be predicted by the improved ESO. The improved NLSEF is adopted to restrain the residual errors of the current-loop. The DCD is used to compensate the overtime variation of the current-loop in real time. The improved ADRC is designed based on a new nonlinear function newfal(·. This function exhibits enhanced continuity and smoothness compared to previously available nonlinear functions. Thus, the new nonlinear function can effectively decrease the high-frequency flutter phenomenon. The improved ADRC exhibits improved control performance, and disturbances of the current-loop can be eliminated by the improved ADRC. Finally, simulation experiments are performed. Results show that the improved ADRC displayed better performance than the proportional integral (PI control strategy and traditional ADRC.

  19. Research on Improved Control Strategy for STATCOM Based on Virtual Matrix Method

    Directory of Open Access Journals (Sweden)

    Wang Xudong

    2016-01-01

    Full Text Available Fast and accurate detection of reactive current is the precondition for the realization of static synchronous compensator (STATCOM reactive power compensation and harmonic suppression. Aiming at deviation and delay of the traditional reactive current detection algorithm with phase-locked loop (PLL and low-pass filter (LPF of STATCOM, a novel improved reactive current detection algorithm without PLL is proposed, in which the virtual matrix (VM is built to replace the original PLL, and improved current average value filter is used to realize the function of LPF, so as to improve the real-time performance and robustness of reactive current detection. The realization process of VM detection method is derived in this paper, and improved control strategy for STATCOM is designed based on the VM detection method. Simulation analysis of the proposed detection algorithm and control strategy is conducted in Matlab platform so as to verify the correctness and effectiveness of the control strategy. The VM detection has the advantages of simple structure, fast response and easy for digital realization, which provides reference for the improvement of reactive power compensation precision for STATCOM.

  20. Control strategies for crane systems: A comprehensive review

    Science.gov (United States)

    Ramli, Liyana; Mohamed, Z.; Abdullahi, Auwalu M.; Jaafar, H. I.; Lazim, Izzuddin M.

    2017-10-01

    Crane systems are tremendously utilised in numerous heavy load transportation industries, and therefore, the control of crane systems is a well-established research field. As the last review paper was published more than a decade ago, there is a lack of collected and organised information regarding the latest and the newest updates on control strategies for crane control systems. Hence, this paper presents a comprehensive review of crane control strategies discussing the latest research works during the years from 2000 to 2016. Various crane types and control issues are highlighted, followed by the main focus of this paper, an extensive review of the control schemes for diverse types of crane systems that have been carried out in the 21st century. A brief review on modelling of single-pendulum and double-pendulum crane systems is also given. In addition, anti-sway control systems for industrial cranes that are available on the market is described. This paper summarises most of the related work and also pays a special focus on research trends regarding the control of crane systems that have been previously published in the literature. It is envisaged that this review paper will be helpful to new researchers when identifying research directions for this particular area of interest.

  1. Controlled invasive mechanical ventilation strategies in obese patients undergoing surgery.

    Science.gov (United States)

    Maia, Lígia de Albuquerque; Silva, Pedro Leme; Pelosi, Paolo; Rocco, Patricia Rieken Macedo

    2017-06-01

    The obesity prevalence is increasing in surgical population. As the number of obese surgical patients increases, so does the demand for mechanical ventilation. Nevertheless, ventilatory strategies in this population are challenging, since obesity results in pathophysiological changes in respiratory function. Areas covered: We reviewed the impact of obesity on respiratory system and the effects of controlled invasive mechanical ventilation strategies in obese patients undergoing surgery. To date, there is no consensus regarding the optimal invasive mechanical ventilation strategy for obese surgical patients, and no evidence that possible intraoperative beneficial effects on oxygenation and mechanics translate into better postoperative pulmonary function or improved outcomes. Expert commentary: Before determining the ideal intraoperative ventilation strategy, it is important to analyze the pathophysiology and comorbidities of each obese patient. Protective ventilation with low tidal volume, driving pressure, energy, and mechanical power should be employed during surgery; however, further studies are required to clarify the most effective ventilation strategies, such as the optimal positive end-expiratory pressure and whether recruitment maneuvers minimize lung injury. In this context, an ongoing trial of intraoperative ventilation in obese patients (PROBESE) should help determine the mechanical ventilation strategy that best improves clinical outcome in patients with body mass index≥35kg/m 2 .

  2. Strategies for detecting and controlling electronic gaming vulnerabilities

    OpenAIRE

    Griffiths, MD

    2008-01-01

    A growing feature of global gaming expansion is the recognition that developing socially responsible guidelines and infrastructure is essential to enhancing the appeal and credibility of the industry. The current financial uncertainties serve to highlight the need for monitoring at risk players, and especially to consider strategies minimising gambling harm before any who are susceptible become confirmed problem gamblers. Prevention, therefore, lies in the vigilance, adaptability and developm...

  3. Mine-hoist active fault tolerant control system and strategy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Wang, Y.; Meng, J.; Zhao, P.; Chang, Y. [China University of Mining and Technology, Xuzhou (China)] wzjsdstu@163.com

    2005-06-01

    Based on fault diagnosis and fault tolerant technologies, the mine-hoist active fault-tolerant control system (MAFCS) is presented with corresponding strategies, which includes the fault diagnosis module (FDM), the dynamic library (DL) and the fault-tolerant control model (FCM). When a fault is judged from some sensor by the FDM, FCM reconfigures the state of the MAFCS by calling the parameters from all sub libraries in DL, in order to ensure the reliability and safety of the mine hoist. The simulating result shows that MAFCS is of certain intelligence, which can adopt the corresponding control strategies according to different fault modes, even when there is quite a difference between the real data and the prior fault modes. 7 refs., 5 figs., 1 tab.

  4. Control of group of mobile autonomous agents via local strategies

    Institute of Scientific and Technical Information of China (English)

    Lixin GAO; Daizhan CHENG; Yiguang HONG

    2008-01-01

    This paper considers the formation control problem of multi-agent systems in a distributed fashion.Two cases of the information propagating topologies among multiple agents,characterized by graphics model,are considered.One is fixed topology.The other is switching topology which represents the limited and less reliable information exchange.The local formation control strategies established in this paper are based on a simple modification of the existing consensus control strategies.Moreover,some existing convergence conditions ale shown to be a special case of our model even in the continuous-time consensus case.Therefore.the results of this paper extend the existing results about the consensus problem.

  5. Strategies for glucose control in people with type 1 diabetes

    DEFF Research Database (Denmark)

    Boiroux, Dimitri; Finan, Daniel Aaron; Jørgensen, John Bagterp

    2011-01-01

    the patient. We minimize the risk of hypoglycemia by introducing a time-varying glucose setpoint based on the announced meal size and the physiological model of the patient. The simulation results are based on a virtual patient simulated by the Hovorka model. They include the cases where the insulin...... sensitivity changes, and mismatches in meal estimation. They demonstrate that the designed controller is able to achieve offset-free control when the insulin sensitivity change, and that having a time-varying reference signal enables more robust control of blood glucose in the cases where the meal size......In this paper we apply a robust feedforward-feedback control strategy to people with type 1 diabetes. The feedforward controller consists of a bolus calculator which compensates the disturbance coming from meals. The feedback controller is based on a linearized description of the model describing...

  6. A Novel Sliding Mode Control Technique for Indirect Current Controlled Active Power Filter

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2012-01-01

    Full Text Available A novel sliding mode control (SMC method for indirect current controlled three-phase parallel active power filter is presented in this paper. There are two designed closed loops in the system: one is the DC voltage controlling loop and the other is the reference current tracking loop. The first loop with a PI regulator is used to control the DC voltage approximating to the given voltage of capacitor, and the output of PI regulator through a low-pass filter is applied as the input of the power supply reference currents. The second loop implements the tracking of the reference currents using integral sliding mode controller, which can improve the harmonic treating performance. Compared with the direct current control technique, it is convenient to be implemented with digital signal processing system because of simpler system structure and better harmonic treating property. Simulation results verify that the generated reference currents have the same amplitude with the load currents, demonstrating the superior harmonic compensating effects with the proposed shunt active power filter compared with the hysteresis method.

  7. High performance predictive current control of a three phase VSI: An ...

    Indian Academy of Sciences (India)

    ... current control of a three phase VSI: An experimental assessment ... Voltage source inverter; two level inverter; predictive current control; weighting factor ... Conventionally, for reference current tracking control in a two level VSI, the objective ...

  8. Architecture and control of a high current ion implanter system

    International Nuclear Information System (INIS)

    Bayer, E.H.; Paul, L.F.; Kranik, J.R.

    1979-01-01

    The design of an ion implant system for use in production requires that special attention be given to areas of design which normally are not emphasized on research or development type ion implanters. Manually operated, local controls are replaced by remote controls, automatic sequencing, and digital displays. For ease of maintenance and replication the individual components are designed as simply as possible and are contained in modules of separate identities, joined only by the beam line and electrical interconnections. A production environment also imposes requirements for the control of contamination and maintainability of clean room integrity. For that reason the major portion of the hardware is separated from the clean operator area and is housed in a maintenance core area. The controls of a production system should also be such that relatively unskilled technicians are able to operate the system with optimum repeatability and minimum operator intervention. An extensive interlock system is required. Most important, for use in production the ion implant system has to have a relatively high rate of throughput. Since the rate of throughput at a given dose is a function of beam current, pumpdown time and wafer handling capacity, design of components affecting these parameters has been optimized. Details of the system are given. (U.K.)

  9. A Communication-Less Distributed Voltage Control Strategy for a Multi-Bus AC Islanded Microgrid

    DEFF Research Database (Denmark)

    Wang, Yanbo; Tan, Yongdong; Chen, Zhe

    2014-01-01

    This paper presents a communication-less distributed voltage control strategy for a multi-bus AC islanded microgrid. First, a Kalman Filter-based network voltage estimator is proposed to obtain voltage responses without communication links in the presence of load disturbances. Then, a voltage...... and reliability is improved for islanded microgrids due to communication-less operation. The simulations and experimental results are presented to validate the proposed distributed voltage control strategy....... optimal controller using MPC (Model Predictive Control) are developed to implement voltage optimal control. The contributions of this paper are demonstrated: (1) The proposed voltage estimator can dynamically obtain network voltage responses just through local voltage and current associated with each DG...

  10. A review of control strategies in closed-loop neuroprosthetic systems

    Directory of Open Access Journals (Sweden)

    James Wright

    2016-07-01

    Full Text Available It has been widely recognized that closed-loop neuroprosthetic systems achieve more favorable outcomes for users then equivalent open-loop devices. Improved performance of tasks, better usability and greater embodiment have all been reported in systems utilizing some form of feedback. However the interdisciplinary work on neuroprosthetic systems can lead to miscommunication due to similarities in well established nomenclature in different fields. Here we present a review of control strategies in existing experimental, investigational and clinical neuroprosthetic systems in order to establish a baseline and promote a common understanding of different feedback modes and closed-loop controllers. The first section provides a brief discussion of feedback control and control theory. The second section reviews the control strategies of recent Brain Machine Interfaces, neuromodulatory implants, neuroprosthetic systems and assistive neurorobotic devices. The final section examines the different approaches to feedback in current neuroprosthetic and neurorobotic systems.

  11. 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

  12. Hierarchical Control Strategy for the Cooperative Braking System of Electric Vehicle

    OpenAIRE

    Peng, Jiankun; He, Hongwen; Liu, Wei; Guo, Hongqiang

    2015-01-01

    This paper provides a hierarchical control strategy for cooperative braking system of an electric vehicle with separated driven axles. Two layers are defined: the top layer is used to optimize the braking stability based on two sliding mode control strategies, namely, the interaxle control mode and signal-axle control strategies; the interaxle control strategy generates the ideal braking force distribution in general braking condition, and the single-axle control strategy can ensure braking s...

  13. Coordinated Control Strategies of VSC-HVDC-Based Wind Power Systems for Low Voltage Ride Through

    Directory of Open Access Journals (Sweden)

    Xinyin Zhang

    2015-07-01

    Full Text Available The Voltage Source Converter-HVDC (VSC-HVDC system applied to wind power generation can solve large scale wind farm grid-connection and long distance transmission problems. However, the low voltage ride through (LVRT of the VSC-HVDC connected wind farm is a key technology issue that must be solved, and it is currently lacking an economic and effective solution. In this paper, a LVRT coordinated control strategy is proposed for the VSC-HVDC-based wind power system. In this strategy, the operation and control of VSC-HVDC and wind farm during the grid fault period is improved. The VSC-HVDC system not only provides reactive power support to the grid, but also effectively maintains the power balance and DC voltage stability by reducing wind-farm power output, without increasing the equipment investment. Correspondingly, to eliminate the influence on permanent magnet synchronous generator (PMSG-based wind turbine (WT systems, a hierarchical control strategy is designed. The speed and validity of the proposed LVRT coordinated control strategy and hierarchical control strategy were verified by MATLAB/Simulink simulations.

  14. Anti-tobacco control industry strategies in Turkey.

    Science.gov (United States)

    Keklik, Seda; Gultekin-Karakas, Derya

    2018-02-26

    Transnational tobacco companies (TTCs) penetrated the Turkish cigarette market due to trade and investment liberalization in the post-1980 period and eventually secured full control. Despite tobacco control policies put in place in reaction to accelerating consumption, TTCs reinforced their market power through a variety of strategies. This paper explores industry strategies that counteract tobacco control policies in Turkey. The study employs both qualitative and quantitative analyses to explore industry strategies in Turkey. Besides the content analyses of industry and market reports, descriptive analyses were conducted for the sub-periods of 1999-2015. The analyses focus on the market strategies of product innovation, advertisement-promotion, cost management and pricing. Rising sales of low tar, ultra-low tar, slim, super-slim and flavoured cigarettes indicate that product innovation served to sustain consumption. Besides, the tobacco industry, using its strong distribution channels, the Internet, and CSR projects, were found to have promoted smoking indirectly. The industry also rationalized manufacturing facilities and reduced the cost of tobacco, making Turkey a cigarette-manufacturing base. Tobacco manufacturers, moreover, offered cigarettes in different price segments and adjusted net prices both up and down according to price categories and market conditions. In response to the successful effect of shifts in price margins, the market share of mid-priced cigarettes expanded while those within the economy category maintained the highest market share. As a result of pricing strategies, net sales revenues increased. Aside from official cigarette sales, the upward trends in the registered and unregistered sales of cigarette substitutes indicate that the demand-side tobacco control efforts remain inadequate. The Turkish case reveals that the resilience of the tobacco industry vis-à-vis mainstream tobacco control efforts necessitates a new policy perspective

  15. Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering

    Science.gov (United States)

    Nau, Thomas; Teuschl, Andreas

    2015-01-01

    Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon. PMID:25621217

  16. Current Advancements and Strategies in Tissue Engineering for Wound Healing: A Comprehensive Review.

    Science.gov (United States)

    Ho, Jasmine; Walsh, Claire; Yue, Dominic; Dardik, Alan; Cheema, Umber

    2017-06-01

    Significance: With an aging population leading to an increase in diabetes and associated cutaneous wounds, there is a pressing clinical need to improve wound-healing therapies. Recent Advances: Tissue engineering approaches for wound healing and skin regeneration have been developed over the past few decades. A review of current literature has identified common themes and strategies that are proving successful within the field: The delivery of cells, mainly mesenchymal stem cells, within scaffolds of the native matrix is one such strategy. We overview these approaches and give insights into mechanisms that aid wound healing in different clinical scenarios. Critical Issues: We discuss the importance of the biomimetic niche, and how recapitulating elements of the native microenvironment of cells can help direct cell behavior and fate. Future Directions: It is crucial that during the continued development of tissue engineering in wound repair, there is close collaboration between tissue engineers and clinicians to maintain the translational efficacy of this approach.

  17. Biological Control Strategies for Mosquito Vectors of Arboviruses.

    Science.gov (United States)

    Huang, Yan-Jang S; Higgs, Stephen; Vanlandingham, Dana L

    2017-02-10

    Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.

  18. Biological Control Strategies for Mosquito Vectors of Arboviruses

    Directory of Open Access Journals (Sweden)

    Yan-Jang S. Huang

    2017-02-01

    Full Text Available Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.

  19. Dual motor drive vehicle speed synchronization and coordination control strategy

    Science.gov (United States)

    Huang, Hao; Tu, Qunzhang; Jiang, Chenming; Ma, Limin; Li, Pei; Zhang, Hongxing

    2018-04-01

    Multi-motor driven systems are more and more widely used in the field of electric engineering vehicles, as a result of the road conditions and the variable load of engineering vehicles, makes multi-motors synchronization coordinated control system as a key point of the development of the electric vehicle drive system. This paper based on electrical machinery transmission speed in the process of engineering vehicles headed for coordinated control problem, summarized control strategies at home and abroad in recent years, made analysis and comparison of the characteristics, finally discussed the trend of development of the multi-motor coordination control, provided a reference for synchronized control system research of electric drive engineering vehicles.

  20. Optimal management strategies in variable environments: Stochastic optimal control methods

    Science.gov (United States)

    Williams, B.K.

    1985-01-01

    Dynamic optimization was used to investigate the optimal defoliation of salt desert shrubs in north-western Utah. Management was formulated in the context of optimal stochastic control theory, with objective functions composed of discounted or time-averaged biomass yields. Climatic variability and community patterns of salt desert shrublands make the application of stochastic optimal control both feasible and necessary. A primary production model was used to simulate shrub responses and harvest yields under a variety of climatic regimes and defoliation patterns. The simulation results then were used in an optimization model to determine optimal defoliation strategies. The latter model encodes an algorithm for finite state, finite action, infinite discrete time horizon Markov decision processes. Three questions were addressed: (i) What effect do changes in weather patterns have on optimal management strategies? (ii) What effect does the discounting of future returns have? (iii) How do the optimal strategies perform relative to certain fixed defoliation strategies? An analysis was performed for the three shrub species, winterfat (Ceratoides lanata), shadscale (Atriplex confertifolia) and big sagebrush (Artemisia tridentata). In general, the results indicate substantial differences among species in optimal control strategies, which are associated with differences in physiological and morphological characteristics. Optimal policies for big sagebrush varied less with variation in climate, reserve levels and discount rates than did either shadscale or winterfat. This was attributed primarily to the overwintering of photosynthetically active tissue and to metabolic activity early in the growing season. Optimal defoliation of shadscale and winterfat generally was more responsive to differences in plant vigor and climate, reflecting the sensitivity of these species to utilization and replenishment of carbohydrate reserves. Similarities could be seen in the influence of both

  1. Analysis of Hydrogen Control Strategy Using Igniter during Severe Accident

    International Nuclear Information System (INIS)

    Lee, Sung Bok; Kim, Hyeong Taek; Lee, Keo Hyoung

    2008-01-01

    The Severe Accident Management Guidelines (SAMGs) for the operating pressurized water reactor (PWR) have been completed within 2006. Among the SAMG strategies, mitigation-07 is the most important strategy for managing a severe accident of a PWR in order to reduce containment hydrogen. The fastest way to reduce the containment hydrogen concentration is to intentionally ignite the hydrogen. For this strategy, igniters exist in Optimized Power Reactor 1000 (OPR 1000) to burn hydrogen for a severe accident. For using the igniters during a severe accident, the adverse effects such as the explosion of the hydrogen mixture should be considered for containment integrity. However, an applicable discrimination method to activate the igniters does not exist, so that the hydrogen control strategy using the igniters cannot be chosen during a severe accident. Thus, this study focused on suggesting an applicable discrimination method to carry out the strategy of using the igniters. In this study, the specific plant used for this analysis is Ulchin Unit 5 and 6, OPR 1000 plant, in Korea

  2. Dynamic flow control strategies of vehicle SCR Urea Dosing System

    Science.gov (United States)

    Lin, Wei; Zhang, Youtong; Asif, Malik

    2015-03-01

    Selective Catalyst Reduction(SCR) Urea Dosing System(UDS) directly affects the system accuracy and the dynamic response performance of a vehicle. However, the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions. That will lead to low NO X conversion efficiency or NH3 slip. In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions, an advanced control strategy based on an air-assisted volumetric UDS is presented. It covers the methods of flow compensation and switching working conditions. The strategy is authenticated on an UDS and tested in different dynamic conditions. The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS. The inject deviation range is improved from being between -8% and 10% to -4% and 2% and became more stable than before, and the dynamic response time was shortened from 200 ms to 150 ms. The ETC cycle result shows that after using the new strategy the NH3 emission is reduced by 60%, and the NO X emission remains almost unchanged. The trade-off between NO X conversion efficiency and NH3 slip is mitigated. The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.

  3. Rehabilitation strategies for partially edentulous-prosthodontic principles and current trends.

    Science.gov (United States)

    D'Souza, Dsj; Dua, Parag

    2011-07-01

    The prosthetic considerations for treatment of partially edentulous patients involve evaluation of important aspects such as presence of certain functional or skeletal deficits, orientation of the occlusal plane, free-way space, size and location of edentulous areas, number, strategic location and quality of the likely abutment teeth, vertical dimension, and the type of occlusion. A comprehensive evaluation, multidisciplinary approach and a sequential treatment plan, worked out in harmony with the patient's perceptions are important factors to ensure a successful outcome. This article discusses the principles, current trends and importance of clinical decisions in designing a treatment strategy when confronted with complex situations of partial edentulism.

  4. Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations

    Directory of Open Access Journals (Sweden)

    Christopher M. Mahoney

    2018-05-01

    Full Text Available Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

  5. Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations.

    Science.gov (United States)

    Mahoney, Christopher M; Imbarlina, Cayla; Yates, Cecelia C; Marra, Kacey G

    2018-01-01

    Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG) is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

  6. TRIANA. A control strategy for Smart Grids. Forecasting, planning and real-time control

    International Nuclear Information System (INIS)

    Bakker, V.

    2012-01-01

    Increasing demand, extra fluctuation and a large share of distributed electricity generation will put more stress on the electricity supply chain. Therefore, changes are required in the supply chain to maintain a properly functioning, stable and affordable grid. Currently the supply chain is completely driven by demand by constantly adapting the production to the demand. The exploitation of flexibility on the demand side of the supply chain allows for a more efficient and sustainable electricity production. Techniques like controllable distributed generation, distributed storage, and smart appliances can introduce this required flexibility. To exploit the new flexibility, the grid has to become more intelligent, i.e. become a Smart Grid. In this thesis TRIANA, a three step control strategy for the Smart Grid is presented. In the first step of TRIANA, the forecasting step, the scheduling freedom (flexibility) of a device is determined for each individual device by a local controller. In the second step, a (central) planner tries to exploit the freedom of the devices determined in the first step for his objective. The last step of TRIANA is the real-time control step performed by the local controller achieving the planning in the best possible way. In order to analyze the impact of control methodologies for Smart Grid, a simulator based on an energy model has been built. The basic elements of the model are individual devices and between devices energy streams are defined. The energy streams are connected via so called pools, which represent the physical connections between the devices. To study the effectiveness of the control methodology and study the most economic use of the flexibility of devices, multiple scenarios have been simulated. Simulations show that TRIANA can optimize the energy flows and can control the operation of the domestic devices in an economic manner without discomfort for the residents. TRIANA is a methodology capable of adjusting the energy

  7. Coordinated Control Strategy for a Hybrid Wind Farm with DFIG and PMSG under Symmetrical Grid Faults

    Directory of Open Access Journals (Sweden)

    Jiawei Li

    2017-05-01

    Full Text Available This paper presents a coordinated control strategy for a hybrid wind farm with doubly-fed induction generator (DFIG- and direct-driven permanent-magnet synchronous generator (PMSG-based wind turbines under symmetrical grid faults. The proposed low-voltage ride-through (LVRT strategy is based on a novel current allocation principle and is implemented for individual DFIG- or PMSG-based wind turbines. No communication equipment between different wind power generators is required. By monitoring the local voltages and active power outputs of the corresponding wind generators, the proposed control strategy can control the hybrid wind farm to provide the maximum reactive power to support the grid voltage during a symmetrical grid fault. As a result, the reduction in the active power output from the hybrid wind farm can be decreased, which also helps avoid generator over-speed issues and supply active power support for the power grid. In addition, the reactive current upper limits of DFIG- and PMSG-based sub-wind farms are investigated by considering different active power outputs and different grid voltage dip depths, and the feasible regions of the two types of sub-wind farms for meeting the LVRT requirements are further studied. Finally, the effectiveness of the proposed coordinated LVRT control strategy for the hybrid wind farm is validated by simulation and experimental results.

  8. A control strategy for multi-functional converter to improve grid power quality

    DEFF Research Database (Denmark)

    Li, Fei; Wang, Xiongfei; Chen, Zhe

    2011-01-01

    The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi-funct......) for multi-functional converter is described. Simulation and hardware in the loop real time test results carried on a three-phase four-wire distributed generation system illustrate the effectiveness of the proposed control strategy.......The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi......-functional converter which can compensate reactive power, harmonic currents, unbalance, and neutral current simultaneously under distorted voltage conditions, besides the active power exchange. The capacity of the converter is taken into account. The proposed control strategy based on synchronous reference frame (SRF...

  9. Control Strategy for Microgrid Inverter under Unbalanced Grid Voltage Conditions

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Zhang, X.

    2014-01-01

    This paper presents the theoretical analysis of the inherent reason of current harmonic and power oscillation phenomena in case of operating the microgrid inverter under unbalanced grid voltage conditions. In order to flexibly control the current harmonic and power oscillation, a new stationary...... inverter. Finally, the performance evaluation tests are carried out under unbalanced grid voltage conditions. Results verify the effectiveness of the propose method....

  10. Predictive control strategies for wind turbine system based on permanent magnet synchronous generator.

    Science.gov (United States)

    Maaoui-Ben Hassine, Ikram; Naouar, Mohamed Wissem; Mrabet-Bellaaj, Najiba

    2016-05-01

    In this paper, Model Predictive Control and Dead-beat predictive control strategies are proposed for the control of a PMSG based wind energy system. The proposed MPC considers the model of the converter-based system to forecast the possible future behavior of the controlled variables. It allows selecting the voltage vector to be applied that leads to a minimum error by minimizing a predefined cost function. The main features of the MPC are low current THD and robustness against parameters variations. The Dead-beat predictive control is based on the system model to compute the optimum voltage vector that ensures zero-steady state error. The optimum voltage vector is then applied through Space Vector Modulation (SVM) technique. The main advantages of the Dead-beat predictive control are low current THD and constant switching frequency. The proposed control techniques are presented and detailed for the control of back-to-back converter in a wind turbine system based on PMSG. Simulation results (under Matlab-Simulink software environment tool) and experimental results (under developed prototyping platform) are presented in order to show the performances of the considered control strategies. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Extreme value analysis for evaluating ozone control strategies.

    Science.gov (United States)

    Reich, Brian; Cooley, Daniel; Foley, Kristen; Napelenok, Sergey; Shaby, Benjamin

    2013-06-01

    Tropospheric ozone is one of six criteria pollutants regulated by the US EPA, and has been linked to respiratory and cardiovascular endpoints and adverse effects on vegetation and ecosystems. Regional photochemical models have been developed to study the impacts of emission reductions on ozone levels. The standard approach is to run the deterministic model under new emission levels and attribute the change in ozone concentration to the emission control strategy. However, running the deterministic model requires substantial computing time, and this approach does not provide a measure of uncertainty for the change in ozone levels. Recently, a reduced form model (RFM) has been proposed to approximate the complex model as a simple function of a few relevant inputs. In this paper, we develop a new statistical approach to make full use of the RFM to study the effects of various control strategies on the probability and magnitude of extreme ozone events. We fuse the model output with monitoring data to calibrate the RFM by modeling the conditional distribution of monitoring data given the RFM using a combination of flexible semiparametric quantile regression for the center of the distribution where data are abundant and a parametric extreme value distribution for the tail where data are sparse. Selected parameters in the conditional distribution are allowed to vary by the RFM value and the spatial location. Also, due to the simplicity of the RFM, we are able to embed the RFM in our Bayesian hierarchical framework to obtain a full posterior for the model input parameters, and propagate this uncertainty to the estimation of the effects of the control strategies. We use the new framework to evaluate three potential control strategies, and find that reducing mobile-source emissions has a larger impact than reducing point-source emissions or a combination of several emission sources.

  12. Minimal average consumption downlink base station power control strategy

    OpenAIRE

    Holtkamp H.; Auer G.; Haas H.

    2011-01-01

    We consider single cell multi-user OFDMA downlink resource allocation on a flat-fading channel such that average supply power is minimized while fulfilling a set of target rates. Available degrees of freedom are transmission power and duration. This paper extends our previous work on power optimal resource allocation in the mobile downlink by detailing the optimal power control strategy investigation and extracting fundamental characteristics of power optimal operation in cellular downlink. W...

  13. Economic implications of three strategies for the control of taeniasis

    OpenAIRE

    Alexander, A.; John, K. R.; Jayaraman, T.; Oommen, A.; Venkata Raghava, M.; Dorny, P.; Rajshekhar, V.

    2011-01-01

    Objective To evaluate the cost-effectiveness of three strategies for the control of taeniasis in a community, in terms of cost per case treated. Methods A study was conducted in South India to determine the prevalence of taeniasis by screening stool samples from 653 randomly chosen subjects, for coproantigens. The costs incurred in the project were used to estimate the cost per case screened and treated. A one-way sensitivity analysis was carried out for varying rates of taeniasis, different ...

  14. Robust quasi NID current and flux control of an induction motor for position control

    NARCIS (Netherlands)

    van Duijnhoven, M.; Blachuta, M.J.

    1999-01-01

    In the paper, a new control design method called Dynamic Contraction method is applied to the flux and quadrature current robust control of an induction motor operated using the field orientation principle. The resulting input-output decoupled and linearized drive is then used for time-optimal

  15. Strategies and criteria for risk-based configuration control

    International Nuclear Information System (INIS)

    Samanta, P.K.; Kim, I.S.; Vesely, W.E.

    1991-01-01

    A configuration, as used here, is a set of component operability or statuses that define the state of a nuclear power plant. Risk-based configuration control is the management of component configurations using a risk perspective to control risk and assure safety. If the component configurations that have high risk implications do not occur then the risk from the operation of nuclear power plants would be minimal. The control of component configurations, i.e., the management of component statuses, so that the risk from components being unavailable is minimized, becomes difficult because the status of a standby safety system component is often not apparent unless it is tested. In this paper, we discuss the strategies and criteria for risk-based configuration control in nuclear power plants. In developing these strategies and criteria, the primary objective is to obtain more direct risk control but the added benefit is the effective use of plant resources. Implementation of such approaches can result in replacement/modification of parts of Technical Specifications. Specifically, the risk impact or safety impact of a configuration depends upon four factors: (1) The configuration components which are simultaneously down (i.e., inoperable); (2) the backup components which are known to be up (i.e., operable); (3) the duration of time the configuration exists (the outage time); and (4) the frequency at which the configuration occurs. Risk-based configuration control involves managing these factors using risk analyses and risk insights. In this paper, we discuss each of the factors and illustrate how they can be controlled. The information and the tools needed in implementing configuration control are also discussed. The risk-based calculation requirements in achieving the control are also delineated. 4 refs., 4 figs., 1 tab

  16. A Current Review of the Diagnostic and Treatment Strategies of Hepatic Encephalopathy

    Directory of Open Access Journals (Sweden)

    Z. Poh

    2012-01-01

    Full Text Available Hepatic encephalopathy (HE is a serious and potentially fatal complication in patients with cirrhotic liver disease. It is a spectrum ranging from minimal hepatic encephalopathy (MHE without recognizable clinical symptoms or signs, to overt HE with risk of cerebral edema and death. HE results in diminished quality of life and survival. The broad range of neuropsychiatric manifestations reflects the range of pathophysiological mechanisms and impairment in neurotransmission that are purported to cause HE including hyperammonemia, astrocyte swelling, intra-astrocytic glutamine, upregulation of 18-kDa translocator protein (TSPO (formerly known as peripheral benzodiazepine receptor or PBTR, and manganese. There is a myriad of diagnostic tools including simple bedside clinical assessment, and more complex neuropsychological batteries and neurophysiological tests available today. Current treatment strategies are directed at reducing ammonia, with newer agents showing some early promise. This paper describes the pathophysiology of the disease and summarises current diagnostic and treatment therapies available.

  17. SP-100 initial startup and restart control strategy

    International Nuclear Information System (INIS)

    Halfen, F.J.; Wong, K.K.; Switick, D.M.; Shukla, J.N.

    1992-01-01

    This paper reports that recent Generic Flight System (GFS) updates have necessitated revisions in the initial startup and restart control strategies. The design changes that have had the most impact on the control strategies are the addition of the Auxiliary Cooling and Thaw (ACT) system for preheating the lithium filled components, changes in the reactivity worths of the reflectors and safety-rods such that initial cold criticality is achieved with only a small amount of reflector movement following the withdrawal of the safety-rods, and the removal of the scram function from the reflectors. Revised control and operating strategies have been developed and tested using the SP-100 dynamic simulation model, ARIES-GFS. The change in the total reactivity worths of the reflectors and safety-rods has eliminated the need for the use of fast and slow reflector drive speeds during the initial on-orbit approach to criticality. The relatively fast removal of the safety-rods results in a near-critical condition so that the use of slow moving (single speed) reflector drives does not add significant time to achieve full power for the initial startup. The use of the ACT system (with its NaK trace-lines for preheating and auxiliary cooling) affects the main Thermoelectric Electro-Magnetic (TEM) pump startup and the time after a shutdown before freezing occurs in the main heat transfer systems

  18. Flexible Power Regulation and Current-limited Control of Grid-connected Inverter under Unbalanced Grid Voltage Faults

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Lu, Zhigang

    2017-01-01

    The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage Fault Ride Through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon...... with the conventional FRT solutions are discussed. The quantitative analysis of three phase current peak values are conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim...

  19. Research on control strategy based on fuzzy PR for grid-connected inverter

    Science.gov (United States)

    Zhang, Qian; Guan, Weiguo; Miao, Wen

    2018-04-01

    In the traditional PI controller, there is static error in tracking ac signals. To solve the problem, the control strategy of a fuzzy PR and the grid voltage feed-forward is proposed. The fuzzy PR controller is to eliminate the static error of the system. It also adjusts parameters of PR controller in real time, which avoids the defect of fixed parameter fixed. The grid voltage feed-forward control can ensure the quality of current and improve the system's anti-interference ability when the grid voltage is distorted. Finally, the simulation results show that the system can output grid current with good quality and also has good dynamic and steady state performance.

  20. Direct-current vector control of three-phase grid-connected rectifier-inverter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuhui; Haskew, Timothy A.; Hong, Yang-Ki; Xu, Ling [Department of Electrical and Computer Engineering, University of Alabama, Tuscaloosa, AL 35475 (United States)

    2011-02-15

    The three-phase grid-connected converter is widely used in renewable and electric power system applications. Traditionally, control of the three-phase grid-connected converter is based on the standard decoupled d-q vector control mechanism. Nevertheless, the study of this paper shows that there is a limitation in the conventional standard vector control method. Some of the limitations have also been found recently by other researchers. To overcome the shortage of the conventional vector control technique, this paper proposes a new direct-current d-q vector control mechanism in a nested-loop control structure, based on which an optimal control strategy is developed in a nonlinear programming formulation. The behaviors of both the conventional and proposed control methods are compared and evaluated in simulation and laboratory hardware experiment environments, both of which demonstrates that the proposed approach is effective for grid-connected power converter control in a wide system conditions while the conventional standard vector control approach may behave improperly especially when the converter operates beyond its PWM saturation limit. (author)

  1. Cell lineage branching as a strategy for proliferative control.

    Science.gov (United States)

    Buzi, Gentian; Lander, Arthur D; Khammash, Mustafa

    2015-02-19

    How tissue and organ sizes are specified is one of the great unsolved mysteries in biology. Experiments and mathematical modeling implicate feedback control of cell lineage progression, but a broad understanding of what lineage feedback accomplishes is lacking. By exploring the possible effects of various biologically relevant disturbances on the dynamic and steady state behaviors of stem cell lineages, we find that the simplest and most frequently studied form of lineage feedback - which we term renewal control - suffers from several serious drawbacks. These reflect fundamental performance limits dictated by universal conservation-type laws, and are independent of parameter choice. Here we show that introducing lineage branches can circumvent all such limitations, permitting effective attenuation of a wide range of perturbations. The type of feedback that achieves such performance - which we term fate control - involves promotion of lineage branching at the expense of both renewal and (primary) differentiation. We discuss the evidence that feedback of just this type occurs in vivo, and plays a role in tissue growth control. Regulated lineage branching is an effective strategy for dealing with disturbances in stem cell systems. The existence of this strategy provides a dynamics-based justification for feedback control of cell fate in vivo.

  2. Control strategies for wind farm power optimization: LES study

    Science.gov (United States)

    Ciri, Umberto; Rotea, Mario; Leonardi, Stefano

    2017-11-01

    Turbines in wind farms operate in off-design conditions as wake interactions occur for particular wind directions. Advanced wind farm control strategies aim at coordinating and adjusting turbine operations to mitigate power losses in such conditions. Coordination is achieved by controlling on upstream turbines either the wake intensity, through the blade pitch angle or the generator torque, or the wake direction, through yaw misalignment. Downstream turbines can be adapted to work in waked conditions and limit power losses, using the blade pitch angle or the generator torque. As wind conditions in wind farm operations may change significantly, it is difficult to determine and parameterize the variations of the coordinated optimal settings. An alternative is model-free control and optimization of wind farms, which does not require any parameterization and can track the optimal settings as conditions vary. In this work, we employ a model-free optimization algorithm, extremum-seeking control, to find the optimal set-points of generator torque, blade pitch and yaw angle for a three-turbine configuration. Large-Eddy Simulations are used to provide a virtual environment to evaluate the performance of the control strategies under realistic, unsteady incoming wind. This work was supported by the National Science Foundation, Grants No. 1243482 (the WINDINSPIRE project) and IIP 1362033 (I/UCRC WindSTAR). TACC is acknowledged for providing computational time.

  3. Controlling the HIV/AIDS epidemic: current status and global challenges

    Directory of Open Access Journals (Sweden)

    Thorsten eDemberg

    2012-08-01

    Full Text Available This review provides an overview of the current status of the global HIV pandemic and strategies to bring it under control. It updates numerous preventive approaches including behavioral interventions, male circumcision, pre- and post-exposure prophylaxis, vaccines, and microbicides. The manuscript summarizes current anti-retroviral treatment options, their impact in the western world, and difficulties faced by emerging and resource-limited nations in providing and maintaining appropriate treatment regimens. Current clinical and pre-clinical approaches towards a cure for HIV are described, including new drug compounds that target viral reservoirs and gene therapy approaches aimed at altering susceptibility to HIV infection. Recent progress in vaccine development is summarized, including novel approaches and new discoveries.

  4. Dynamic performance analysis of permanent magnet contactor with a flux-weakening control strategy

    Science.gov (United States)

    Wang, Xianbing; Lin, Heyun; Fang, Shuhua; Jin, Ping; Wang, Junhua; Ho, S. L.

    2011-04-01

    A new flux-weakening control strategy for permanent magnet contactors is proposed. By matching the dynamic attraction force and the antiforce, the terminal velocity and collision energy of the movable iron in the closing process are significantly reduced. The movable iron displacement is estimated by detecting the closing voltage and current with the proposed control. A dynamic mathematical model is also established under four kinds of excitation scenarios. The attraction force and flux linkage are predicted by finite element method and the dynamics of the closing process is simulated using the 4th-order Runge-Kutta algorithm. Experiments are carried out on a 250A prototype with an intelligent control unit to verify the proposed control strategy.

  5. A Virtual Inertia Control Strategy for DC Microgrids Analogized with Virtual Synchronous Machines

    DEFF Research Database (Denmark)

    Wu, Wenhua; Chen, Yandong; Luo, An

    2017-01-01

    In a DC microgrid (DC-MG), the dc bus voltage is vulnerable to power fluctuation derived from the intermittent distributed energy or local loads variation. In this paper, a virtual inertia control strategy for DC-MG through bidirectional grid-connected converters (BGCs) analogized with virtual...... synchronous machine (VSM) is proposed to enhance the inertia of the DC-MG, and to restrain the dc bus voltage fluctuation. The small-signal model of the BGC system is established, and the small-signal transfer function between the dc bus voltage and the dc output current of the BGC is deduced. The dynamic...... for the BGC is introduced to smooth the dynamic response of the dc bus voltage. By analyzing the control system stability, the appropriate virtual inertia control parameters are selected. Finally, simulations and experiments verified the validity of the proposed control strategy....

  6. Design strategy for control of inherently safe reactors

    International Nuclear Information System (INIS)

    Chisholm, G.H.

    1984-01-01

    Reactor power plant safety is assured through a combination of engineered barriers to radiation release (e.g., reactor containment) in combination with active reactor safety systems to shut the reactor down and remove decay heat. While not specifically identified as safety systems, the control systems responsible for continuous operation of plant subsystems are the first line of defense for mitigating radiation releases and for plant protection. Inherently safe reactors take advantage of passive system features for decay-heat removal and reactor shutdown functions normally ascribed to active reactor safety systems. The advent of these reactors may permit restructuring of the present control system design strategy. This restructuring is based on the fact that authority for protection against unlikely accidents is, as much as practical, placed upon the passive features of the system instead of the traditional placement upon the PPS. Consequently, reactor control may be simplified, allowing the reliability of control systems to be improved and more easily defended

  7. Chaos control in an economic model via minimum entropy strategy

    Energy Technology Data Exchange (ETDEWEB)

    Salarieh, Hassan [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of); National Research Institute for Science Policy (NRISP), Soheil Street, Shirazi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

    2009-04-30

    In this paper, minimum entropy algorithm for controlling chaos, is applied to a Cournot duopoly with different constant marginal costs, as a discrete-time dynamical system which shows chaotic behavior. The ME control is implemented through delayed feedback. It is assumed that the equations of the dynamical system are not known, so the feedback gain cannot be obtained analytically from the system equations. In the ME method the feedback gain is obtained adaptively in such a way that the entropy of the system converges to zero, hence a fixed point of the system will be stabilized. Application of the proposed method with different economic control strategies is numerically investigated. Simulation results show the effectiveness of the ME method for controlling chaos in economic systems with unknown equations.

  8. Soil environmental quality in greenhouse vegetable production systems in eastern China: Current status and management strategies.

    Science.gov (United States)

    Hu, Wenyou; Zhang, Yanxia; Huang, Biao; Teng, Ying

    2017-03-01

    Greenhouse vegetable production (GVP) has become an important source of public vegetable consumption and farmers' income in China. However, various pollutants can be accumulated in GVP soils due to the high cropping index, large agricultural input, and closed environment. Ecological toxicity caused by excessive pollutants' accumulation can then lead to serious health risks. This paper was aimed to systematically review the current status of soil environmental quality, analyze their impact factors, and consequently to propose integrated management strategies for GVP systems. Results indicated a decrease in soil pH, soil salinization, and nutrients imbalance in GVP soils. Fungicides, remaining nutrients, antibiotics, heavy metals, and phthalate esters were main pollutants accumulating in GVP soils comparing to surrounding open field soils. Degradation of soil ecological function, accumulation of major pollutants in vegetables, deterioration of neighboring water bodies, and potential human health risks has occurred due to the changes of soil properties and accumulation of pollutants such as heavy metals and fungicides in soils. Four dominant factors were identified leading to the above-mentioned issues including heavy application of agricultural inputs, outmoded planting styles with poor environmental protection awareness, old-fashion regulations, unreasonable standards, and ineffective supervisory management. To guarantee a sustainable GVP development, several strategies were suggested to protect and improve soil environmental quality. Implementation of various strategies not only requires the concerted efforts among different stakeholders, but also the whole lifecycle assessment throughout the GVP processes as well as effective enforcement of policies, laws, and regulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Current strategies for the restoration of adequate lordosis during lumbar fusion

    Science.gov (United States)

    Barrey, Cédric; Darnis, Alice

    2015-01-01

    Not restoring the adequate lumbar lordosis during lumbar fusion surgery may result in mechanical low back pain, sagittal unbalance and adjacent segment degeneration. The objective of this work is to describe the current strategies and concepts for restoration of adequate lordosis during fusion surgery. Theoretical lordosis can be evaluated from the measurement of the pelvic incidence and from the analysis of spatial organization of the lumbar spine with 2/3 of the lordosis given by the L4-S1 segment and 85% by the L3-S1 segment. Technical aspects involve patient positioning on the operating table, release maneuvers, type of instrumentation used (rod, screw-rod connection, interbody cages), surgical sequence and the overall surgical strategy. Spinal osteotomies may be required in case of fixed kyphotic spine. AP combined surgery is particularly efficient in restoring lordosis at L5-S1 level and should be recommended. Finally, not one but several strategies may be used to achieve the need for restoration of adequate lordosis during fusion surgery. PMID:25621216

  10. Regenerating the human heart: direct reprogramming strategies and their current limitations.

    Science.gov (United States)

    Ghiroldi, Andrea; Piccoli, Marco; Ciconte, Giuseppe; Pappone, Carlo; Anastasia, Luigi

    2017-10-27

    Cardiovascular diseases are the leading cause of death in the Western world. Unfortunately, current therapies are often only palliative, consequently essentially making heart transplantation necessary for many patients. However, several novel therapeutic approaches in the past two decades have yielded quite encouraging results. The generation of induced pluripotent stem cells, through the forced expression of stem cell-specific transcription factors, has inspired the most promising strategies for heart regeneration by direct reprogramming of cardiac fibroblasts into functional cardiomyocytes. Initial attempts at this reprogramming were conducted using a similar approach to the one used with transcription factors, but during years, novel strategies have been tested, e.g., miRNAs, recombinant proteins and chemical molecules. Although preliminary results on animal models are promising, the low reprogramming efficiency, as well as the incomplete maturation of the cardiomyocytes, still represents important obstacles. This review covers direct transdifferentiation strategies that have been proposed and developed and illustrates the pros and cons of each approach. Indeed, as described in the manuscript, there are still many unanswered questions and drawbacks that require a better understanding of the basic signaling pathways and transcription factor networks before functional cells, suitable for cardiac regeneration and safe for the patients, can be generated and used for human therapies.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  12. Cancer in Angola, resources and strategy for its control.

    Science.gov (United States)

    Lopes, Lygia Vieira; Conceição, Ana Vaz; Oliveira, João Blasques; Tavares, António; Domingos, Clarinha; Santos, Lucio Lara

    2012-01-01

    Cancer is an increasingly important health problem in Africa. The number of cancer cases in this region could double, ranging between 700 000 and 1 600 000 new cases in 2030. The mortality rate is higher than 80% and is explained, mainly, by a lack of early detection, diagnostics and treatment resources. In Angola, about 7,000 patients die of cancer every year. Data were derived from open-ended interviews conducted in 2010-11 with health authorities, clinicians, nurses and Administration of Hospitals. According Angola epidemiological data, results of interviews and international published advocacy for cancer control we develop a potential strategy for its control. The objectives are to identify existing resources for cancer control and describe the needs thereto, in order to establish an oncological program to guide the development of Angola cancer control strategies. Malaria remains the leading cause of illness and death in Angola, and other communicable diseases remain a public health problem. However, 9 000 new cases of cancer are diagnosed each year.The most common types of cancer are: cancer of the cervix, breast, prostate, esophagus, stomach and head and neck, as well as cancers with infectious origin, such as Kaposi's sarcoma and liver and bladder cancer. The foundation for developing national cancer control strategies includes: oncological data; investment and training; identifying and removing barriers; guidance and protection of the patient. Angolan National Cancer Centre, Sagrada Esperança Clinic and Girassol Clinic are now developing a cancer program. Improving the economic situation of Angola creates conditions for an increase in life expectancy which in itself is associated with an increased risk of oncological diseases. On the other hand, infectious diseases, associated with the risk of malignant tumors, are endemic. Thus, an increase in patients with malignant disease is expected. A plan is therefore necessary to organize the response to this old

  13. Improved Control Strategy for T-type Isolated DC/DC Converters

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Wang, Yanbo

    2017-01-01

    T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters....... Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal–oxide–semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC...

  14. Nonlinear control strategy based on using a shape-tunable neural controller

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.; Peng, S. [Feng Chia Univ, Taichung (Taiwan, Province of China). Department of chemical Engineering; Chang, W. [Feng Chia Univ, Taichung (Taiwan, Province of China). Department of Automatic Control

    1997-08-01

    In this paper, a nonlinear control strategy based on using a shape-tunable neural network is developed for adaptive control of nonlinear processes. Based on the steepest descent method, a learning algorithm that enables the neural controller to possess the ability of automatic controller output range adjustment is derived. The novel feature of automatic output range adjustment provides the neural controller more flexibility and capability, and therefore the scaling procedure, which is usually unavoidable for the conventional fixed-shape neural controllers, becomes unnecessary. The advantages and effectiveness of the proposed nonlinear control strategy are demonstrated through the challenge problem of controlling an open-loop unstable nonlinear continuous stirred tank reactor (CSTR). 14 refs., 11 figs.

  15. Current trends in small vocabulary speech recognition for equipment control

    Science.gov (United States)

    Doukas, Nikolaos; Bardis, Nikolaos G.

    2017-09-01

    Speech recognition systems allow human - machine communication to acquire an intuitive nature that approaches the simplicity of inter - human communication. Small vocabulary speech recognition is a subset of the overall speech recognition problem, where only a small number of words need to be recognized. Speaker independent small vocabulary recognition can find significant applications in field equipment used by military personnel. Such equipment may typically be controlled by a small number of commands that need to be given quickly and accurately, under conditions where delicate manual operations are difficult to achieve. This type of application could hence significantly benefit by the use of robust voice operated control components, as they would facilitate the interaction with their users and render it much more reliable in times of crisis. This paper presents current challenges involved in attaining efficient and robust small vocabulary speech recognition. These challenges concern feature selection, classification techniques, speaker diversity and noise effects. A state machine approach is presented that facilitates the voice guidance of different equipment in a variety of situations.

  16. Seizing Control: From Current Treatments to Optogenetic Interventions in Epilepsy.

    Science.gov (United States)

    Bui, Anh D; Alexander, Allyson; Soltesz, Ivan

    2015-12-23

    The unpredictability and severity of seizures contribute to the debilitating nature of epilepsy. These factors also render the condition particularly challenging to treat, as an ideal treatment would need to detect and halt the pathological bursts of hyperactivity without disrupting normal brain activity. Optogenetic techniques offer promising tools to study and perhaps eventually treat this episodic disorder by controlling specific brain circuits in epileptic animals with great temporal precision. Here, we briefly review the current treatment options for patients with epilepsy. We then describe the many ways optogenetics has allowed us to untangle the microcircuits involved in seizure activity, and how it has, in some cases, changed our perception of previous theories of seizure generation. Control of seizures with light is no longer a dream, and has been achieved in numerous different animal models of epilepsy. Beyond its application as a seizure suppressor, we highlight another facet of optogenetics in epilepsy, namely the ability to create "on-demand" seizures, as a tool to systematically probe the dynamics of networks during seizure initiation and propagation. Finally, we look into the future to discuss the possibilities and challenges of translating optogenetic techniques to clinical use. © The Author(s) 2015.

  17. HIV cure strategies: how good must they be to improve on current antiretroviral therapy?

    Directory of Open Access Journals (Sweden)

    Paul E Sax

    Full Text Available We examined efficacy, toxicity, relapse, cost, and quality-of-life thresholds of hypothetical HIV cure interventions that would make them cost-effective compared to life-long antiretroviral therapy (ART.We used a computer simulation model to assess three HIV cure strategies: Gene Therapy, Chemotherapy, and Stem Cell Transplantation (SCT, each compared to ART. Efficacy and cost parameters were varied widely in sensitivity analysis. Outcomes included quality-adjusted life expectancy, lifetime cost, and cost-effectiveness in dollars/quality-adjusted life year ($/QALY gained. Strategies were deemed cost-effective with incremental cost-effectiveness ratios <$100,000/QALY.For patients on ART, discounted quality-adjusted life expectancy was 16.4 years and lifetime costs were $591,400. Gene Therapy was cost-effective with efficacy of 10%, relapse rate 0.5%/month, and cost $54,000. Chemotherapy was cost-effective with efficacy of 88%, relapse rate 0.5%/month, and cost $12,400/month for 24 months. At $150,000/procedure, SCT was cost-effective with efficacy of 79% and relapse rate 0.5%/month. Moderate efficacy increases and cost reductions made Gene Therapy cost-saving, but substantial efficacy/cost changes were needed to make Chemotherapy or SCT cost-saving.Depending on efficacy, relapse rate, and cost, cure strategies could be cost-effective compared to current ART and potentially cost-saving. These results may help provide performance targets for developing cure strategies for HIV.

  18. Control systems for ITER diagnostics, heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Simrock, Stefan, E-mail: stefan.simrock@iter.org

    2016-11-15

    The ITER Diagnostic, Heating and Current Drive systems might appear, on the face of it, to have very different control requirements. There are approximately 45 diagnostic systems, including magnetic sensors for plasma position and shape determination, imaging systems in the IR and visible, Thompson scattering for electron temperature and density, neutron detectors and collective scattering for alpha particle density and energy distribution. The H&CD systems encompass Electron Cyclotron Heating, using 24 1MW, 170 GHz gyrotrons and 5 steerable launchers to deliver 20 MW to the plasma, Ion Cyclotron Heating, using 8 3MW, 40–55 MHz sources and two multi-element launchers to deliver 20 MW to the plasma, and 2 Negative Ion Neutral Beam Injectors, each of which can deliver up to 16.5 MW of 1 MeV beams to the plasma. Although there are substantial differences in the needs for protection, when handling multi-MW heating systems, and in data throughput for many diagnostics, the formal processes needed to translate system requirements into Instrumentation and Control are identical. Due to the distributed procurement of ITER sub-systems and the need to integrate as painlessly as possible to CODAC, the formal processes, together with a substantial degree of standardization, are even more than usually essential. Starting from the technical, safety and protection, integration and operation requirements, a loop of functional analysis and signal listing is used to generate the controller configuration and the conceptual architecture. These elements in their turn lead to the physical and software design. The paper will describe the formal processes of control system design and the methods used by the ITER project to achieve the standardization of systems engineering practices. These have been applied to several use-cases covering all operation relevant phases such as plasma operation, maintenance, testing and conditioning. There are a number of running contracts that are developing

  19. Disruptions in ITER and strategies for their control and mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Lehnen, M., E-mail: michael.lehnen@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Aleynikova, K.; Aleynikov, P.B.; Campbell, D.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Drewelow, P. [Max-Planck-Institut für Plasmaphysik, Greifswald branch, EURATOM Ass., D-17491 Greifswald (Germany); Eidietis, N.W. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Gasparyan, Yu. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, Moscow 115409 (Russian Federation); Granetz, R.S. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Gribov, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Hartmann, N. [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research—Plasma Physics, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Jülich (Germany); Hollmann, E.M. [University of California-San Diego, La Jolla, CA 92093 (United States); Izzo, V.A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Jachmich, S. [Laboratory for Plasma Physics, ERM/KMS, Association EURATOM – Belgian State, B-1000 Brussels (Belgium); Kim, S.-H.; Kočan, M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Koslowski, H.R. [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research—Plasma Physics, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Jülich (Germany); Kovalenko, D. [SRC RF TRINITI, ul. Pushkovykh, vladenie 12, Troitsk, Moscow 142190 (Russian Federation); Kruezi, U. [CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); and others

    2015-08-15

    The thermal and electromagnetic loads related to disruptions in ITER are substantial and require careful design of tokamak components to ensure they reach the projected lifetime and to ensure that safety relevant components fulfil their function for the worst foreseen scenarios. The disruption load specifications are the basis for the design process of components like the full-W divertor, the blanket modules and the vacuum vessel and will set the boundary conditions for ITER operations. This paper will give a brief overview on the disruption loads and mitigation strategies for ITER and will discuss the physics basis which is continuously refined through the current disruption R&D programs.

  20. Interlink Converter with Linear Quadratic Regulator Based Current Control for Hybrid AC/DC Microgrid

    Directory of Open Access Journals (Sweden)

    Dwi Riana Aryani

    2017-11-01

    Full Text Available A hybrid alternate current/direct current (AC/DC microgrid consists of an AC subgrid and a DC subgrid, and the subgrids are connected through the interlink bidirectional AC/DC converter. In the stand-alone operation mode, it is desirable that the interlink bidirectional AC/DC converter manages proportional power sharing between the subgrids by transferring power from the under-loaded subgrid to the over-loaded one. In terms of system security, the interlink bidirectional AC/DC converter takes an important role, so proper control strategies need to be established. In addition, it is assumed that a battery energy storage system is installed in one subgrid, and the coordinated control of interlink bidirectional AC/DC converter and battery energy storage system converter is required so that the power sharing scheme between subgrids becomes more efficient. For the purpose of designing a tracking controller for the power sharing by interlink bidirectional AC/DC converter in a hybrid AC/DC microgrid, a droop control method generates a power reference for interlink bidirectional AC/DC converter based on the deviation of the system frequency and voltages first and then interlink bidirectional AC/DC converter needs to transfer the power reference to the over-loaded subgrid. For efficiency of this power transferring, a linear quadratic regulator with exponential weighting for the current regulation of interlink bidirectional AC/DC converter is designed in such a way that the resulting microgrid can operate robustly against various uncertainties and the power sharing is carried out quickly. Simulation results show that the proposed interlink bidirectional AC/DC converter control strategy provides robust and efficient power sharing scheme between the subgrids without deteriorating the secure system operation.