Operation strategy for a lab-scale grid-connected photovoltaic generation system integrated with battery energy storage

International Nuclear Information System (INIS)

Jou, Hurng-Liahng; Chang, Yi-Hao; Wu, Jinn-Chang; Wu, Kuen-Der

2015-01-01

Highlights: • The operation strategy for grid-connected PV generation system integrated with battery energy storage is proposed. • The PV system is composed of an inverter and two DC-DC converter. • The negative impact of grid-connected PV generation systems on the grid can be alleviated by integrating a battery. • The operation of the developed system can be divided into nine modes. - Abstract: The operation strategy for a lab-scale grid-connected photovoltaic generation system integrated with battery energy storage is proposed in this paper. The photovoltaic generation system is composed of a full-bridge inverter, a DC–DC boost converter, an isolated bidirectional DC–DC converter, a solar cell array and a battery set. Since the battery set acts as an energy buffer to adjust the power generation of the solar cell array, the negative impact on power quality caused by the intermittent and unstable output power from a solar cell array is alleviated, so the penetration rate of the grid-connected photovoltaic generation system is increased. A lab-scale prototype is developed to verify the performance of the system. The experimental results show that it achieves the expected performance

Hierarchical Load Tracking Control of a Grid-Connected Solid Oxide Fuel Cell for Maximum Electrical Efficiency Operation

Directory of Open Access Journals (Sweden)

Yonghui Li

2015-03-01

Full Text Available Based on the benchmark solid oxide fuel cell (SOFC dynamic model for power system studies and the analysis of the SOFC operating conditions, the nonlinear programming (NLP optimization method was used to determine the maximum electrical efficiency of the grid-connected SOFC subject to the constraints of fuel utilization factor, stack temperature and output active power. The optimal operating conditions of the grid-connected SOFC were obtained by solving the NLP problem considering the power consumed by the air compressor. With the optimal operating conditions of the SOFC for the maximum efficiency operation obtained at different active power output levels, a hierarchical load tracking control scheme for the grid-connected SOFC was proposed to realize the maximum electrical efficiency operation with the stack temperature bounded. The hierarchical control scheme consists of a fast active power control and a slower stack temperature control. The active power control was developed by using a decentralized control method. The efficiency of the proposed hierarchical control scheme was demonstrated by case studies using the benchmark SOFC dynamic model.

Variable frequency operation of active stall wind farms using a dc connection to grid

DEFF Research Database (Denmark)

Iov, Florin; Blaabjerg, Frede; Sorensen, Poul

2005-01-01

Currently, there is an increasing trend to connect large MW wind farms to the transmISSIon system. Requirements that focus on the influence of the farms on the grid stability and power quality, and on the control capabilities of wind farms have already been established. The main trends of modern...... wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...

A Space Operations Network Alternative: Using Globally Connected Research and Education Networks for Space-Based Science Operations

Science.gov (United States)

Bradford, Robert N.

2006-01-01

Earth based networking in support of various space agency projects has been based on leased service/circuits which has a high associated cost. This cost is almost always taken from the science side resulting in less science. This is a proposal to use Research and Education Networks (RENs) worldwide to support space flight operations in general and space-based science operations in particular. The RENs were developed to support scientific and educational endeavors. They do not provide support for general Internet traffic. The connectivity and performance of the research and education networks is superb. The connectivity at Layer 3 (IP) virtually encompasses the globe. Most third world countries and all developed countries have their own research and education networks, which are connected globally. Performance of the RENs especially in the developed countries is exceptional. Bandwidth capacity currently exists and future expansion promises that this capacity will continue. REN performance statistics has always exceeded minimum requirements for spaceflight support. Research and Education networks are more loosely managed than a corporate network but are highly managed when compared to the commodity Internet. Management of RENs on an international level is accomplished by the International Network Operations Center at Indiana University at Indianapolis. With few exceptions, each regional and national REN has its own network ops center. The acceptable use policies (AUP), although differing by country, allows any scientific program or project the use of their networks. Once in compliance with the first RENs AUP, all others will accept that specific traffic including regional and transoceanic networks. RENs can support spaceflight related scientific programs and projects. Getting the science to the researcher is obviously key to any scientific project. RENs provide a pathway to virtually any college or university in the world, as well as many governmental institutes and

The sharp bounds on general sum-connectivity index of four operations on graphs

Directory of Open Access Journals (Sweden)

Shehnaz Akhter

2016-09-01

Full Text Available Abstract The general sum-connectivity index χ α ( G $\\chi_{\\alpha}(G$ , for a (molecular graph G, is defined as the sum of the weights ( d G ( a 1 + d G ( a 2 α $(d_{G}(a_{1}+d_{G}(a_{2}^{\\alpha}$ of all a 1 a 2 ∈ E ( G $a_{1}a_{2}\\in E(G$ , where d G ( a 1 $d_{G}(a_{1}$ (or d G ( a 2 $d_{G}(a_{2}$ denotes the degree of a vertex a 1 $a_{1}$ (or a 2 $a_{2}$ in the graph G; E ( G $E(G$ denotes the set of edges of G, and α is an arbitrary real number. Eliasi and Taeri (Discrete Appl. Math. 157:794-803, 2009 introduced four new operations based on the graphs S ( G $S(G$ , R ( G $R(G$ , Q ( G $Q(G$ , and T ( G $T(G$ , and they also computed the Wiener index of these graph operations in terms of W ( F ( G $W(F(G$ and W ( H $W(H$ , where F is one of the symbols S, R, Q, T. The aim of this paper is to obtain sharp bounds on the general sum-connectivity index of the four operations on graphs.

Line operators in theories of class S, quantized moduli space of flat connections, and Toda field theory

International Nuclear Information System (INIS)

Coman, Ioana; Teschner, Joerg

2015-05-01

Non-perturbative aspects of N=2 supersymmetric gauge theories of class S are deeply encoded in the algebra of functions on the moduli space M flat of at SL(N)-connections on Riemann surfaces. Expectation values of Wilson and 't Hooft line operators are related to holonomies of flat connections, and expectation values of line operators in the low-energy effective theory are related to Fock-Goncharov coordinates on M flat . Via the decomposition of UV line operators into IR line operators, we determine their noncommutative algebra from the quantization of Fock-Goncharov Laurent polynomials, and find that it coincides with the skein algebra studied in the context of Chern-Simons theory. Another realization of the skein algebra is generated by Verlinde network operators in Toda field theory. Comparing the spectra of these two realizations provides non-trivial support for their equivalence. Our results can be viewed as evidence for the generalization of the AGT correspondence to higher-rank class S theories.

Connecting engineering operations to strategic management: a framework for decision making in engineering offshoring

DEFF Research Database (Denmark)

Hansen, Zaza Nadja Lee; Ahmed-Kristensen, Saeema

2012-01-01

of the organisation. The Global Decision-Making (GDM) framework described here is a decision-making framework for engineering offshoring decisions for product development activities. The framework proposes that risks in engineering offshoring can be reduced by connecting engineering operations to strategic management...

Hierarchical Load Tracking Control of a Grid-connected Solid Oxide Fuel Cell for Maximum Electrical Efficiency Operation

DEFF Research Database (Denmark)

Li, Yonghui; Wu, Qiuwei; Zhu, Haiyu

2015-01-01

efficiency operation obtained at different active power output levels, a hierarchical load tracking control scheme for the grid-connected SOFC was proposed to realize the maximum electrical efficiency operation with the stack temperature bounded. The hierarchical control scheme consists of a fast active...... power control and a slower stack temperature control. The active power control was developed by using a decentralized control method. The efficiency of the proposed hierarchical control scheme was demonstrated by case studies using the benchmark SOFC dynamic model......Based on the benchmark solid oxide fuel cell (SOFC) dynamic model for power system studies and the analysis of the SOFC operating conditions, the nonlinear programming (NLP) optimization method was used to determine the maximum electrical efficiency of the grid-connected SOFC subject...

Operational Planning of Low-Energy District Heating Systems Connected to Existing Buildings

DEFF Research Database (Denmark)

Tol, Hakan; Svendsen, Svend

2012-01-01

. The response of the radiator heating systems at different levels of supply temperature was used to form the operational planning of the low-energy DH system, which determined the design parameters of the low-energy DH network in terms of overall mass flow requirement and the return temperature from...... the buildings. Since the existing buildings were considered to be renovated to low-energy class, the operational planning was simultaneously modelled for both present high-demand and future low-demand situations of the same case area.......This article focuses on low-energy District Heating (DH) systems operating in low-temperatures such as 55°C in terms of supply and 25°C in terms of return in connection with existing buildings. Since the heat loss from the network has a significant impact in case of supplying heat to low...

Open-circuit fault detection and tolerant operation for a parallel-connected SAB DC-DC converter

DEFF Research Database (Denmark)

Park, Kiwoo; Chen, Zhe

2014-01-01

This paper presents an open-circuit fault detection method and its tolerant control strategy for a Parallel-Connected Single Active Bridge (PCSAB) dc-dc converter. The structural and operational characteristics of the PCSAB converter lead to several advantages especially for high power applicatio...

Challenges to Grid Synchronization of Single-Phase Grid-Connected Inverters in Zero-Voltage Ride-Through Operation

DEFF Research Database (Denmark)

Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

With the fast development in Photovoltaic (PV) technology, the relevant grid-connection requirements/standards are continuously being updated, and more challenges have been imposed on both single-phase and three-phase grid-connected PV systems. For instance, PV systems are currently required...... to remain connected under grid voltage sags (even zero voltage condition). In this case, much attention should be paid to the grid synchronization in such a way to properly ride-through grid faults. Thus, in this paper, the most commonly-used and recently-developed Phase Locked Loop (PLL) synchronization...... methods have been evaluated for single-phase grid-connected PV systems in the case of Zero-Voltage Ride-Through (ZVRT) operation. The performances of the prior-art PLL methods in response to zero voltage faults in terms of detection precision and dynamic response are assessed in this paper. Simulation...

Connected Vehicle Pilot Deployment Program phase 1 : security management operating concept : New York City : final report.

Science.gov (United States)

2016-05-18

This document describes the Security Management Operating Concept (SMOC) for the New York City Department of Transportation (NYCDOT) Connected Vehicle Pilot Deployment (CVPD) Project. This SMOC outlines the security mechanisms that will be used to pr...

Droop-Controlled Inverters with Seamless Transition between Islanding and Grid-Connected Operations

DEFF Research Database (Denmark)

Hu, Shang-Hung; Kuo, Chun-Yi; Lee, Tzung-Lin

2011-01-01

This paper presents a seamless transition method for droop-controlled inverters to operate in both islanding and grid-connected modes. A local PLL and a virtual inductance are designed to ride through transient when the inverter switches between two modes with no synchronization. The proposed...... method can cooperatively work with well-developed droop controls so that the inverters are able to share load among them as well as subsist under transient events of the utility. Theoretical analysis and experimental results validate effectiveness of the proposed method....

Hitchin's connection, Toeplitz operators, and symmetry invariant deformation quantization

DEFF Research Database (Denmark)

Andersen, Jørgen Ellegaard

2012-01-01

We introduce the notion of a rigid family of Kähler structures on a symplectic manifold. We then prove that a Hitchin connection exists for any rigid holomorphic family of Kähler structures on any compact pre-quantizable symplectic manifold which satisfies certain simple topological constraints...... a mapping class group invariant formal quantization of the smooth symplectic leaves of the moduli space of flat SU(n)-connections on any compact surface....... quantization. Finally, these results are applied to the moduli space situation in which Hitchin originally constructed his connection. First we get a proof that the Hitchin connection in this case is the same as the connection constructed by Axelrod, Della Pietra, and Witten. Second we obtain in this way...

Sharing data between mobile devices, connected vehicles and infrastructure - task 3: concept of operations : technical memorandum -final.

Science.gov (United States)

2016-07-13

This report describes the concept of operation for the use of mobile devices in a connected vehicle environment. Specifically, it identifies the needs, conceptual system, and potential scenarios that serve as the basis for demonstrating both safety a...

Making Connections

Science.gov (United States)

Pien, Cheng Lu; Dongsheng, Zhao

2011-01-01

Effective teaching includes enabling learners to make connections within mathematics. It is easy to accord with this statement, but how often is it a reality in the mathematics classroom? This article describes an approach in "connecting equivalent" fractions and whole number operations. The authors illustrate how a teacher can combine a common…

Integrating Emerging Data Sources into Operational Practice: Capabilities and Limitations of Devices to Collect, Compile, Save, and Share Messages from CAVs and Connected Travelers

Science.gov (United States)

2018-03-01

Connected and automated vehicles (CAVs) and connected travelers will be providing substantially increased levels of data which will be available for agencies to consider using to improve the management and operation of the surface transportation syst...

Optimal scheduling for vehicle-to-grid operation with stochastic connection of plug-in electric vehicles to smart grid

International Nuclear Information System (INIS)

Jian, Linni; Zheng, Yanchong; Xiao, Xinping; Chan, C.C.

2015-01-01

Highlights: • A novel event-triggered scheduling scheme for vehicle-to-grid (V2G) operation is proposed. • New scheme can handle the uncertainty arising from stochastic connection of electric vehicles. • New scheme aims at minimizing the overall load variance of power grid by V2G operation. • Method to evaluate the performance of proposed scheme is elaborated and demonstrated. - Abstract: Vehicle-to-grid (V2G) operation of plug-in electric vehicles (PEVs) is attracting increasing attention since it can assist to improve the efficiency and reliability of power grid, as well as reduce the operating cost and greenhouse gas emission of electric vehicles. Within the scheme of V2G operation, PEVs are expected to serve as a novel distributed energy storage system (ESS) to help achieve the balance between supply and demand of power grid. One of the key difficulties concerning its practical implementation lies in that the availability of PEVs as ESS for grid remains highly uncertain due to their mobility as transportation tools. To address this issue, a novel event-triggered scheduling scheme for V2G operation based on the scenario of stochastic PEV connection to smart grid is proposed in this paper. Firstly, the mathematical model is formulated. Secondly, the preparation of input data for systematic evaluation is introduced and the case study is conducted. Finally, statistic analysis results demonstrate that our proposed V2G scheduling scheme can dramatically smooth out the fluctuation in power load profiles

Dynamic Supply Chain Design and Operations Plan for Connected Smart Factories with Additive Manufacturing

Directory of Open Access Journals (Sweden)

Byung Do Chung

2018-04-01

Full Text Available Interest in smart factories and smart supply chains has been increasing, and researchers have emphasized the importance and the effects of advanced technologies such as 3D printers, the Internet of Things, and cloud services. This paper considers an innovation in dynamic supply-chain design and operations: connected smart factories that share interchangeable processes through a cloud-based system for personalized production. In the system, customers are able to upload a product design file, an optimal supply chain design and operations plan are then determined based on the available resources in the network of smart factories. The concept of smart supply chains is discussed and six types of flexibilities are identified, namely: design flexibility, product flexibility, process flexibility, supply chain flexibility, collaboration flexibility, and strategic flexibility. Focusing on supply chain flexibility, a general planning framework and various optimization models for dynamic supply chain design and operations plan are proposed. Further, numerical experiments are conducted to analyze fixed, production, and transportation costs for various scenarios. The results demonstrate the extent of the dynamic supply chain design and operations problem, and the large variation in transportation cost.

Flicker Mitigation of Grid Connected Wind Turbines Using STATCOM

DEFF Research Database (Denmark)

Sun, Tao; Chen, Zhe; Blaabjerg, Frede

2004-01-01

to the point of common coupling (PCC) to relieve the flicker produced by grid connected wind turbines and the corresponding control scheme is described in detail. Simulation results show that STATCOM is an effective measure to mitigate the flicker level during continuous operation of grid connected wind......Grid connected wind turbines may produce flicker during continuous operation. In this paper flicker emission of grid connected wind turbines with doubly fed induction generators is investigated during continuous operation. A STATCOM using PWM voltage source converter (VSC) is connected in shunt...

Generalized coupling resonance modeling, analysis, and active damping of multi-parallel inverters in microgrid operating in grid-connected mode

DEFF Research Database (Denmark)

Chen, Zhiyong; Chen, Yandong; Guerrero, Josep M.

2016-01-01

This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic...

Automated and connected vehicle (AV/CV) test bed to improve transit, bicycle, and pedestrian safety : concept of operations plan.

Science.gov (United States)

2017-02-01

This document presents the Concept of Operations (ConOps) Plan for the Automated and Connected Vehicle (AV/CV) Test Bed to Improve Transit, Bicycle, and Pedestrian Safety. As illustrated in Figure 1, the plan presents the overarching vision and goals...

Control scheme towards enhancing power quality and operational efficiency of single-phase two-stage grid-connected photovoltaic systems

Directory of Open Access Journals (Sweden)

Mahmoud Salem

2015-12-01

Full Text Available Achieving high reliable grid-connected photovoltaic (PV systems with high power quality and high operation efficiency is highly required for distributed generation units. A double grid-frequency voltage ripple is found on the dc-link voltage in single-phase photovoltaic grid-connected systems due to the unbalance of the instantaneous dc input and ac output powers. This voltage ripple has undesirable effects on the power quality and operational efficiency of the whole system. Harmonic distortion in the injected current to the grid is one of the problems caused by this double grid-frequency voltage ripple. The double grid frequency ripple propagates to the PV voltage and current which disturb the extracted maximum power from the PV array. This paper introduces intelligent solutions towards mitigate the side effects of the double grid-frequency voltage ripple on the transferred power quality and the operational efficiency of single-phase two-stage grid-connected PV system. The proposed system has three control loops: MPPT control loop, dc-link voltage control loop and inverter current control loop. Solutions are introduced for all the three control loops in the system. The current controller cancels the dc-link voltage effect on the total harmonic distortion of the output current. The dc-link voltage controller is designed to generate a ripple free reference current signal that leads to enhance the quality of the output power. Also a modified MPPT controller is proposed to optimize the extracted power from the PV array. Simulation results show that higher injected power quality is achieved and higher efficiency of the overall system is realized.

Connectivity editing for quadrilateral meshes

KAUST Repository

Peng, Chihan

2011-12-12

We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.

Connectivity editing for quadrilateral meshes

KAUST Repository

Peng, Chihan; Zhang, Eugene; Kobayashi, Yoshihiro; Wonka, Peter

2011-01-01

We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.

Battery sizing and rule-based operation of grid-connected photovoltaic-battery system: A case study in Sweden

International Nuclear Information System (INIS)

Zhang, Yang; Lundblad, Anders; Campana, Pietro Elia; Benavente, F.; Yan, Jinyue

2017-01-01

Highlights: • Battery sizing and rule-based operation are achieved concurrently. • Hybrid operation strategy that combines different strategies is proposed. • Three operation strategies are compared through multi-objective optimization. • High Net Present Value and Self Sufficiency Ratio are achieved at the same time. - Abstract: The optimal components design for grid-connected photovoltaic-battery systems should be determined with consideration of system operation. This study proposes a method to simultaneously optimize the battery capacity and rule-based operation strategy. The investigated photovoltaic-battery system is modeled using single diode photovoltaic model and Improved Shepherd battery model. Three rule-based operation strategies—including the conventional operation strategy, the dynamic price load shifting strategy, and the hybrid operation strategy—are designed and evaluated. The rule-based operation strategies introduce different operation parameters to run the system operation. multi-objective Genetic Algorithm is employed to optimize the decisional variables, including battery capacity and operation parameters, towards maximizing the system’s Self Sufficiency Ratio and Net Present Value. The results indicate that employing battery with the conventional operation strategy is not profitable, although it increases Self Sufficiency Ratio. The dynamic price load shifting strategy has similar performance with the conventional operation strategy because the electricity price variation is not large enough. The proposed hybrid operation strategy outperforms other investigated strategies. When the battery capacity is lower than 72 kW h, Self Sufficiency Ratio and Net Present Value increase simultaneously with the battery capacity.

Design for sustainability: rural connectivity with village operators

CSIR Research Space (South Africa)

Roux, K

2011-10-01

Full Text Available South Africa has approximately 26500 primary and secondary schools, of which at least 17000 are in remote rural villages. None of these rural schools have any form of Internet connectivity. The same rural villages may have one health facility...

Design of the integration interface between the EU HCPB TBM and the ITER TBM port plug including hot cell operations for connection

International Nuclear Information System (INIS)

Neuberger, H.; Boccaccini, L.V.; Roccella, R.

2007-01-01

In the frame of the activities of the EU Breeder Blanket Programme and of the Test Blanket Working Group, the Helium Cooled Pebble Bed Test Blanket Module- (HCPB-TBM) System is developed. The TBM test schedule foresees four different campaigns for simulation of DEMO relevant conditions, campaign requires a dedicate TBM. Therefore a concept for TBM integration into ITER is designed with attention to simplify the mounting/dismounting operations. This paper presents the status of this concept with regard to the operations in hot cell required to install a new TBM into an equatorial TBM Port Plug (PP). This includes the establishment of the connection for the attachment, supply- and diagnostic lines in the environment of the interface (IF 1) between the TBM rear part and the PP backside shield. The connection of IF 1 has to be designed to cope with a temperature difference between TBM and PP (∝200 K) and the EM-loads during normal operation and disruption scenarios. The reference attachment concept based on shear keys and flexible cartridges is revised to cope with new conditions on the load and at the interface to the PP. According to the latest results of EM analysis, a radial component of the Maxwell forces (due to the ferromagnetic structural material) has been identified as an additional challenging load for the attachment. Furthermore, the replacing operations at IF 1 are influenced by the design of the PP; the recent ITER proposal based on a removable back side shield allows access to the IF 1 from the periphery after the frame of the PP surrounding the TBM is removed. As for the mechanical attachment, the tools and operations for connection of the TBM supply lines (Helium-, Purge- and measurement lines for different purpose depending on the test schedule) are strongly influenced by the restrictions to access IF 1, too. Dismantling of the frame would allow direct access to the interface by e.g. orbital welding tools. The concept for connection of the TBM

Adaptive Protection Scheme for a Distribution System Considering Grid-Connected and Islanded Modes of Operation

Directory of Open Access Journals (Sweden)

Yavuz Ates

2016-05-01

Full Text Available The renewable energy-based distributed generation (DG implementation in power systems has been an active research area during the last few decades due to several environmental, economic and political factors. Although the integration of DG offers many advantages, several concerns, including protection schemes in systems with the possibility of bi-directional power flow, are raised. Thus, new protection schemes are strongly required in power systems with a significant presence of DG. In this study, an adaptive protection strategy for a distribution system with DG integration is proposed. The proposed strategy considers both grid-connected and islanded operating modes, while the adaptive operation of the protection is dynamically realized considering the availability of DG power production (related to faults or meteorological conditions in each time step. Besides, the modular structure and fast response of the proposed strategy is validated via simulations conducted on the IEEE 13-node test system.

Formulae and Bounds connected to Optimal Design and Homogenization of Partial Differential Operators and Integral Functionals

Energy Technology Data Exchange (ETDEWEB)

Lukkassen, D.

1996-12-31

When partial differential equations are set up to model physical processes in strongly heterogeneous materials, effective parameters for heat transfer, electric conductivity etc. are usually required. Averaging methods often lead to convergence problems and in homogenization theory one is therefore led to study how certain integral functionals behave asymptotically. This mathematical doctoral thesis discusses (1) means and bounds connected to homogenization of integral functionals, (2) reiterated homogenization of integral functionals, (3) bounds and homogenization of some particular partial differential operators, (4) applications and further results. 154 refs., 11 figs., 8 tabs.

Prioritizing connection requests in GMPLS-controlled optical networks

DEFF Research Database (Denmark)

Ruepp, Sarah Renée; Koster, A.; Andriolli, N.

2009-01-01

We prioritize bidirectional connection requests by combining dynamic connection provisioning with off-line optimization. Results show that the proposed approach decreases wavelength-converter usage, thereby allowing operators to reduce blocking-probably under bulk connection assignment or network...

Dual connectivity for LTE-advanced heterogeneous networks

DEFF Research Database (Denmark)

Wang, Hua; Rosa, Claudio; Pedersen, Klaus I.

2016-01-01

Dual connectivity (DC) allows user equipments (UEs) to receive data simultaneously from different eNodeBs (eNBs) in order to boost the performance in a heterogeneous network with dedicated carrier deployment. Yet, how to efficiently operate with DC opens a number of research questions. In this pa......Dual connectivity (DC) allows user equipments (UEs) to receive data simultaneously from different eNodeBs (eNBs) in order to boost the performance in a heterogeneous network with dedicated carrier deployment. Yet, how to efficiently operate with DC opens a number of research questions...... aggregation (CA) and virtually zerolatency fronthaul connections, and in any case it is significantly higher compared to the case without DC. Keywords: Dual connectivity Heterogeneous network LTE-advanced Radio resource management Performance evaluation...

31 CFR 30.14 - Q-14: How does section 111 of EESA operate in connection with an acquisition, merger, or...

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Q-14: How does section 111 of EESA operate in connection with an acquisition, merger, or reorganization? 30.14 Section 30.14 Money and Finance: Treasury Office of the Secretary of the Treasury TARP STANDARDS FOR COMPENSATION AND CORPORATE...

Battery impedance spectroscopy using bidirectional grid connected

Indian Academy of Sciences (India)

Keywords. Impedance spectroscopy; grid connection; battery converter; state of charge; health monitoring ... The converter is grid connected and controlled to operate at unity power factor. Additional ... Sadhana. Current Issue : Vol. 43, Issue 6.

Research on wind power grid-connected operation and dispatching strategies of Liaoning power grid

Science.gov (United States)

Han, Qiu; Qu, Zhi; Zhou, Zhi; He, Xiaoyang; Li, Tie; Jin, Xiaoming; Li, Jinze; Ling, Zhaowei

2018-02-01

As a kind of clean energy, wind power has gained rapid development in recent years. Liaoning Province has abundant wind resources and the total installed capacity of wind power is in the forefront. With the large-scale wind power grid-connected operation, the contradiction between wind power utilization and peak load regulation of power grid has been more prominent. To this point, starting with the power structure and power grid installation situation of Liaoning power grid, the distribution and the space-time output characteristics of wind farm, the prediction accuracy, the curtailment and the off-grid situation of wind power are analyzed. Based on the deep analysis of the seasonal characteristics of power network load, the composition and distribution of main load are presented. Aiming at the problem between the acceptance of wind power and power grid adjustment, the scheduling strategies are given, including unit maintenance scheduling, spinning reserve, energy storage equipment settings by the analysis of the operation characteristics and the response time of thermal power units and hydroelectric units, which can meet the demand of wind power acceptance and provide a solution to improve the level of power grid dispatching.

Evaluation of different operational strategies for lithium ion battery systems connected to a wind turbine for primary frequency regulation and wind power forecast accuracy improvement

Energy Technology Data Exchange (ETDEWEB)

Swierczynski, Maciej; Stroe, Daniel Ioan; Stan, Ana Irina; Teodorescu, Remus; Andreasen, Soeren Juhl [Aalborg Univ. (Denmark). Dept. of Energy Technology

2012-07-01

High penetration levels of variable wind energy sources can cause problems with their grid integration. Energy storage systems connected to wind turbine/wind power plants can improve predictability of the wind power production and provide ancillary services to the grid. This paper investigates economics of different operational strategies for Li-ion systems connected to wind turbines for wind power forecast accuracy improvement and primary frequency regulation. (orig.)

Parity and the spin{statistics connection

Indian Academy of Sciences (India)

A simple demonstration of the spin-statistics connection for general causal fields is obtained by using the parity operation to exchange spatial coordinates in the scalar product of a locally commuting field operator, evaluated at position x, with the same field operator evaluated at -x, at equal times.

Flexible operation of parallel grid-connecting converters under unbalanced grid voltage

DEFF Research Database (Denmark)

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

2017-01-01

-link voltage ripple, and overloading. Moreover, under grid voltage unbalance, the active power delivery ability is decreased due to the converter's current rating limitation. In this paper, a thorough study on the current limitation of the grid-connecting converter under grid voltage unbalance is conducted....... In addition, based on the principle that total output active power should be oscillation free, a coordinated control strategy is proposed for the parallel grid-connecting converters. The case study has been conducted to demonstrate the effectiveness of this proposed control strategy....

On the space of connections having non-trivial twisted harmonic spinors

International Nuclear Information System (INIS)

Bei, Francesco; Waterstraat, Nils

2015-01-01

We consider Dirac operators on odd-dimensional compact spin manifolds which are twisted by a product bundle. We show that the space of connections on the twisting bundle which yields an invertible operator has infinitely many connected components if the untwisted Dirac operator is invertible and the dimension of the twisting bundle is sufficiently large

On the space of connections having non-trivial twisted harmonic spinors

Energy Technology Data Exchange (ETDEWEB)

Bei, Francesco, E-mail: bei@math.hu-berlin.de [Institut für Mathematik, Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin (Germany); Waterstraat, Nils, E-mail: n.waterstraat@kent.ac.uk [School of Mathematics, Statistics & Actuarial Science, University of Kent, Canterbury, Kent CT2 7NF (United Kingdom)

2015-09-15

We consider Dirac operators on odd-dimensional compact spin manifolds which are twisted by a product bundle. We show that the space of connections on the twisting bundle which yields an invertible operator has infinitely many connected components if the untwisted Dirac operator is invertible and the dimension of the twisting bundle is sufficiently large.

Computer system operation

International Nuclear Information System (INIS)

Lee, Young Jae; Lee, Hae Cho; Lee, Ho Yeun; Kim, Young Taek; Lee, Sung Kyu; Park, Jeong Suk; Nam, Ji Wha; Kim, Soon Kon; Yang, Sung Un; Sohn, Jae Min; Moon, Soon Sung; Park, Bong Sik; Lee, Byung Heon; Park, Sun Hee; Kim, Jin Hee; Hwang, Hyeoi Sun; Lee, Hee Ja; Hwang, In A.

1993-12-01

The report described the operation and the trouble shooting of main computer and KAERINet. The results of the project are as follows; 1. The operation and trouble shooting of the main computer system. (Cyber 170-875, Cyber 960-31, VAX 6320, VAX 11/780). 2. The operation and trouble shooting of the KAERINet. (PC to host connection, host to host connection, file transfer, electronic-mail, X.25, CATV etc.). 3. The development of applications -Electronic Document Approval and Delivery System, Installation the ORACLE Utility Program. 22 tabs., 12 figs. (Author) .new

Computer system operation

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Jae; Lee, Hae Cho; Lee, Ho Yeun; Kim, Young Taek; Lee, Sung Kyu; Park, Jeong Suk; Nam, Ji Wha; Kim, Soon Kon; Yang, Sung Un; Sohn, Jae Min; Moon, Soon Sung; Park, Bong Sik; Lee, Byung Heon; Park, Sun Hee; Kim, Jin Hee; Hwang, Hyeoi Sun; Lee, Hee Ja; Hwang, In A [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1993-12-01

The report described the operation and the trouble shooting of main computer and KAERINet. The results of the project are as follows; 1. The operation and trouble shooting of the main computer system. (Cyber 170-875, Cyber 960-31, VAX 6320, VAX 11/780). 2. The operation and trouble shooting of the KAERINet. (PC to host connection, host to host connection, file transfer, electronic-mail, X.25, CATV etc.). 3. The development of applications -Electronic Document Approval and Delivery System, Installation the ORACLE Utility Program. 22 tabs., 12 figs. (Author) .new.

The connection-set algebra--a novel formalism for the representation of connectivity structure in neuronal network models.

Science.gov (United States)

Djurfeldt, Mikael

2012-07-01

The connection-set algebra (CSA) is a novel and general formalism for the description of connectivity in neuronal network models, from small-scale to large-scale structure. The algebra provides operators to form more complex sets of connections from simpler ones and also provides parameterization of such sets. CSA is expressive enough to describe a wide range of connection patterns, including multiple types of random and/or geometrically dependent connectivity, and can serve as a concise notation for network structure in scientific writing. CSA implementations allow for scalable and efficient representation of connectivity in parallel neuronal network simulators and could even allow for avoiding explicit representation of connections in computer memory. The expressiveness of CSA makes prototyping of network structure easy. A C+ + version of the algebra has been implemented and used in a large-scale neuronal network simulation (Djurfeldt et al., IBM J Res Dev 52(1/2):31-42, 2008b) and an implementation in Python has been publicly released.

Connected Filtering by Reconstruction : Basis and New Advances

NARCIS (Netherlands)

Wilkinson, Michael H.F.

2008-01-01

Openings-by-reconstruction are the oldest connected filters, and indeed, reconstruction methodology lies at the heart of many connected operators such as levelings. Starting out from the basic reconstruction principle of iterated geodesic dilations, extensions such as the use of reconstruction

CONNECTED FILTERING BY RECONSTRUCTION : BASIS AND NEW ADVANCES

NARCIS (Netherlands)

Wilkinson, Michael H. F.

2008-01-01

Openings-by-reconstruction are the oldest connected filters, and indeed, reconstruction methodology lies at the heart of many connected operators such as levelings. Starting out from the basic reconstruction principle of iterated geodesic dilations, extensions such as the use of reconstruction

Projective Connections and the Algebra of Densities

International Nuclear Information System (INIS)

George, Jacob

2008-01-01

Projective connections first appeared in Cartan's papers in the 1920's. Since then they have resurfaced periodically in, for example, integrable systems and perhaps most recently in the context of so called projectively equivariant quantisation. We recall the notion of projective connection and describe its relation with the algebra of densities on a manifold. In particular, we construct a Laplace-type operator on functions using a Thomas projective connection and a symmetric contravariant tensor of rank 2 ('upper metric').

Visualization of Operational Performance of Grid-Connected PV Systems in Selected European Countries

Directory of Open Access Journals (Sweden)

Bala Bhavya Kausika

2018-05-01

Full Text Available This paper presents the results of the analyses of operational performance of small-sized residential PV systems, connected to the grid, in the Netherlands and some other European countries over three consecutive years. Web scraping techniques were employed to collect detailed yield data at high time resolution (5–15 min from a large number (31,844 of systems with 741 MWp of total capacity, delivering data continuously for at least one year. Annual system yield data was compared from small and medium-sized installations. Cartography and spatial analysis techniques in a geographic information system (GIS were used to visualize yield and performance ratio, which greatly facilitates the assessment of performance for geographically scattered systems. Variations in yield and performance ratios over the years were observed with higher values in 2015 due to higher irradiation values. The potential of specific yield and performance maps lies in the updating of monitoring databases, quality control of data, and availability of irradiation data. The automatic generation of performance maps could be a trend in future mapping.

Connections on the state-space over conformal field theories

International Nuclear Information System (INIS)

Ranganathan, K.; Sonoda, H.; Zwiebach, B.

1994-01-01

Motivated by the problem of background independence of closed string field theory we study geometry on the infinite vector bundle of local fields over the space of conformal field theories (CFTs). With any connection we can associate an excluded domain D for the integral of marginal operators, and an operator one-form ω μ . The pair (D, ω μ ) determines the covariant derivative of any correlator of local fields. We obtain interesting classes of connections in which ω μ 's can be written in terms of CFT data. For these connections we compute their curvatures in terms of four-point correlators, D, and ω μ . Among these connections three are of particular interest. A flat, metric compatible connection Γ, and connections c and c with non-vanishing curvature, with the latter metric compatible. The flat connection cannot be used to do parallel transport over a finite distance. Parallel transport with either c or c, however, allows us to construct a CFT in the state-space of another CFT a finite distance away. The construction is given in the form of perturbation theory manifestly free of divergences. (orig.)

Biomass and bio-fuel based poly-generation for off-grid and grid-connected operation. Final technical report

Energy Technology Data Exchange (ETDEWEB)

2012-07-01

The overall objective of this project was to design and build a combined heat and power plant based on an updraft gasifier and a 35 kW electrical output Stirling engine and further to test the flexibility of the plant with regards to fuel and application. In the project a containerized combined heat and power plant including a 200 kW updraft gasifier and a 35 kW electrical output Stirling engine was designed, the specified components were procured, the plant was installed in the three containers and the plant was erected at Amagerforbraendingen ready for the COP15 in November 2009. The potential of operating the Stirling engine in island-mode (without grid connection) was investigated by mathematical modelling. Using an absorption cooling plant connected to the Stirling CHP plant was also investigated. A technical feasibility study was undertaken and it was concluded that from the two available technologies (water/LiBr and Ammonia/water) the appropriate choice is depending on the required cooling temperature. Test runs focussed on investigating the fuel flexibility of two different configurations of Stirling engine CHP plants were carried out - respectively the updraft gasifier plant (the containerized plant and the DTU plant) and the pyrolysis plant (the plant situated at Barritskov). In order to perform these test runs a stable operation is required. On both the containerized plant and the pyrolysis plant this proved to be more challenging than expected and therefore the number of fuels tested was limited to willow chips at the containerized plant and dry wood residues, wood pellets and straw pellets on the pyrolysis plant. For all tested fuels it was possible to operate the plants, however different issues mainly related to the quality of the fuels were encountered. And so it can be concluded that the quality of the fuel is critical for the operation of both the updraft gasifier plant and the pyrolysis plant. A comprehensive desktop evaluation of the feasibility

Operating characteristic analysis of a 400 mH class HTS DC reactor in connection with a laboratory scale LCC type HVDC system

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung-Kyu, E-mail: power@changwon.ac.kr [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Kim, Kwangmin; Park, Minwon [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Lee, Sangjin [Uiduk University, Gyeongju 780-713 (Korea, Republic of)

2015-11-15

Highlights: • A 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC transmission system. • The 400 mH class HTS DC reactor was connected to real power network via the HVDC system. • The DC current flowed in HTS DC reactor has several harmonic components and it was analyzed using FFT. - Abstract: High temperature superconducting (HTS) devices are being developed due to their advantages. Most line commutated converter based high voltage direct current (HVDC) transmission systems for long-distance transmission require large inductance of DC reactor; however, generally, copper-based reactors cause a lot of electrical losses during the system operation. This is driving researchers to develop a new type of DC reactor using HTS wire. The authors have developed a 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC system and applied the HTS DC reactor to the HVDC system to investigate their operating characteristics. The 400 mH class HTS DC reactor is designed using a toroid type magnet. The HVDC system is designed in the form of a mono-pole system with thyristor-based 12-pulse power converters. In this paper, the investigation results of the HTS DC reactor in connection with the HVDC system are described. The operating characteristics of the HTS DC reactor are analyzed under various operating conditions of the system. Through the results, applicability of an HTS DC reactor in an HVDC system is discussed in detail.

Operating characteristic analysis of a 400 mH class HTS DC reactor in connection with a laboratory scale LCC type HVDC system

International Nuclear Information System (INIS)

Kim, Sung-Kyu; Kim, Kwangmin; Park, Minwon; Yu, In-Keun; Lee, Sangjin

2015-01-01

Highlights: • A 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC transmission system. • The 400 mH class HTS DC reactor was connected to real power network via the HVDC system. • The DC current flowed in HTS DC reactor has several harmonic components and it was analyzed using FFT. - Abstract: High temperature superconducting (HTS) devices are being developed due to their advantages. Most line commutated converter based high voltage direct current (HVDC) transmission systems for long-distance transmission require large inductance of DC reactor; however, generally, copper-based reactors cause a lot of electrical losses during the system operation. This is driving researchers to develop a new type of DC reactor using HTS wire. The authors have developed a 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC system and applied the HTS DC reactor to the HVDC system to investigate their operating characteristics. The 400 mH class HTS DC reactor is designed using a toroid type magnet. The HVDC system is designed in the form of a mono-pole system with thyristor-based 12-pulse power converters. In this paper, the investigation results of the HTS DC reactor in connection with the HVDC system are described. The operating characteristics of the HTS DC reactor are analyzed under various operating conditions of the system. Through the results, applicability of an HTS DC reactor in an HVDC system is discussed in detail.

Single bus star connected reluctance drive and method

Science.gov (United States)

Fahimi, Babak; Shamsi, Pourya

2016-05-10

A system and methods for operating a switched reluctance machine includes a controller, an inverter connected to the controller and to the switched reluctance machine, a hysteresis control connected to the controller and to the inverter, a set of sensors connected to the switched reluctance machine and to the controller, the switched reluctance machine further including a set of phases the controller further comprising a processor and a memory connected to the processor, wherein the processor programmed to execute a control process and a generation process.

A guide to distribution network operator connection and use of system methodologies and charging

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-05-04

This report aims to help those developing or planning to develop power generation schemes connected to local electricity distribution systems (distributed generation) to understand the various regional network charging schemes in the UK. It is also intended to act as a route map to understand distribution charges as they are currently applied; further changes in charging arrangements between 2005 and 2010 are indicated and signposts to sources of further information are provided. The report explains the structure of distribution networks, the outcome of the regulatory review of distribution pricing undertaken by the Office of Gas and Electricity Markets (Ofgem) applicable from 1 April 2005 and how this affects distribution network operators (DNOs) and their distribution charges. The report considers: the energy policy framework in the UK; the commercial and regulatory framework that applies to distributed generators; DNOs and their regulatory framework; network charging methodologies and principles; charging statements; and areas of likely future changes. Individual schedules and contact details are given in an appendix for each DNO.

Conservation of connectivity of model-space effective interactions under a class of similarity transformation

International Nuclear Information System (INIS)

Duan Changkui; Gong Yungui; Dong Huining; Reid, Michael F.

2004-01-01

Effective interaction operators usually act on a restricted model space and give the same energies (for Hamiltonian) and matrix elements (for transition operators, etc.) as those of the original operators between the corresponding true eigenstates. Various types of effective operators are possible. Those well defined effective operators have been shown to be related to each other by similarity transformation. Some of the effective operators have been shown to have connected-diagram expansions. It is shown in this paper that under a class of very general similarity transformations, the connectivity is conserved. The similarity transformation between Hermitian and non-Hermitian Rayleigh-Schroedinger perturbative effective operators is one of such transformations and hence the connectivity can be deducted from each other

Conservation of connectivity of model-space effective interactions under a class of similarity transformation.

Science.gov (United States)

Duan, Chang-Kui; Gong, Yungui; Dong, Hui-Ning; Reid, Michael F

2004-09-15

Effective interaction operators usually act on a restricted model space and give the same energies (for Hamiltonian) and matrix elements (for transition operators, etc.) as those of the original operators between the corresponding true eigenstates. Various types of effective operators are possible. Those well defined effective operators have been shown to be related to each other by similarity transformation. Some of the effective operators have been shown to have connected-diagram expansions. It is shown in this paper that under a class of very general similarity transformations, the connectivity is conserved. The similarity transformation between Hermitian and non-Hermitian Rayleigh-Schrodinger perturbative effective operators is one of such transformations and hence the connectivity can be deducted from each other.

A single phase photovoltaic inverter control for grid connected system

Indian Academy of Sciences (India)

This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

Cognitive Connected Vehicle Information System Design Requirement for Safety: Role of Bayesian Artificial Intelligence

OpenAIRE

Ata Khan

2013-01-01

Intelligent transportation systems (ITS) are gaining acceptance around the world and the connected vehicle component of ITS is recognized as a high priority research and development area in many technologically advanced countries. Connected vehicles are expected to have the capability of safe, efficient and eco-driving operations whether these are under human control or in the adaptive machine control mode of operations. The race is on to design the capability to operate in connected traffic ...

Impact of connection density on regional cost differences for network operators in the Netherlands

International Nuclear Information System (INIS)

2009-04-01

The Dutch Office of Energy Regulation ('Energiekamer') has an obligation to investigate the extent to which the electricity and gas distribution businesses (DNOs) in the Netherlands face different structural environments that result in regional cost differences which, in turn, could justify tariff differences. On the basis of previous studies, Energiekamer has identified 'water crossings' and 'local taxes' as allowable regional differences. To account for them, Energiekamer has introduced an adjustment to the regulated revenues formula in order to guarantee a level-playing field to the Dutch DNOs. In addition to these factors, it has been claimed that connection density may have an impact on distribution costs and that, therefore, regulated revenues should be adjusted to compensate for regional differences in connection density between DNOs. However, so far, the research in this field has been unable to identify a sufficiently robust relationship between cost and connection density to support this claim. In order to address this issue, Energiekamer has asked Frontier Economics and Consentec to further investigate the relationship between connection density and distribution costs in the Netherlands. Therefore, our analysis has aimed at determining whether, and to what extent, connection density in the Netherlands is a significant driver of the costs of electricity and gas distribution networks. The following three questions are answered: (1) Is connection density a significant cost driver in electricity and gas networks in the Netherlands?; (2) If so, which functional form (e.g. U-shaped) does this relationship have in the Netherlands?; (3) Finally, based on the evidence collected, is the influence of connection density sufficiently well-determined to be considered a regional difference in the Dutch regulatory framework?

Application of Fuzzy Control in a Photovoltaic Grid-Connected Inverter

Directory of Open Access Journals (Sweden)

Zhaohong Zheng

2018-01-01

Full Text Available To realize the maximum power output of a grid-connected inverter, the MPPT (maximum power point tracking control method is needed. The perturbation and observation (P&O method can cause the inverter operating point to oscillate near the maximum power. In this paper, the fuzzy control P&O method is proposed, and the fuzzy control algorithm is applied to the disturbance observation method. The simulation results of the P&O method with fuzzy control and the traditional P&O method prove that not only can the new method reduce the power loss caused by inverter oscillation during maximum power point tracking, but also it has the advantage of speed. Inductive loads in the post-grid-connected stage cause grid-connected current distortion. A fuzzy control algorithm is added to the traditional deadbeat grid-connected control method to improve the quality of the system’s grid-connected operation. The fuzzy deadbeat control method is verified by experiments, and the harmonic current of the grid-connected current is less than 3%.

Operational Amplifer Integrator

NARCIS (Netherlands)

van Tuijl, Adrianus Johannes Maria

2003-01-01

An integrator circuit comprises an operational amplifier which has a transistor stage (1) with an input terminal (4) and an output terminal (3), a feedback capacitor (2) connected between the input terminal (4) and the output terminal (3), and a resistor (5) connected to the input terminal (4), and

Study of connected system of automatic control of load and operation efficiency of a steam boiler with extremal controller on a simulation model

Science.gov (United States)

Sabanin, V. R.; Starostin, A. A.; Repin, A. I.; Popov, A. I.

2017-02-01

The problems of operation effectiveness increase of steam boilers are considered. To maintain the optimum fuel combustion modes, it is proposed to use an extremal controller (EC) determining the value of airflow rate, at which the boiler generating the desired amount of heat will consume a minimum amount of fuel. EC sets the determined value of airflow rate to airflow rate controller (ARC). The test results of numerical simulation dynamic nonlinear model of steam boiler with the connected system of automatic control of load and combustion efficiency using EC are presented. The model is created in the Simulink modeling package of MATLAB software and can be used to optimize the combustion modes. Based on the modeling results, the conclusion was drawn about the possibility in principle of simultaneously boiler load control and optimizing by EC the combustion modes when changing the fuel combustion heat and the boiler characteristics and its operating mode. It is shown that it is possible to automatically control the operation efficiency of steam boilers when using EC without applying the standard flue gas analyzers. The article considers the numerical simulation dynamic model of steam boiler with the schemes of control of fuel consumption and airflow rate, the steam pressure and EC; the purpose of using EC in the scheme with linear controllers and the requirements to the quality of its operation; the results of operation of boiler control schemes without EC with estimation of influence of roughness of thermal mode maps on the nature of static and dynamic connection of the control units of fuel consumption and airflow rate; the phase trajectories and the diagrams of transient processes occurring in the control scheme with EC with stepped changing the fuel quality and boiler characteristics; analysis of modeling results and prospects for using EC in the control schemes of boilers.

Current Harmonics from Single-Phase Grid-Connected Inverters

DEFF Research Database (Denmark)

Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

2016-01-01

Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

Cross connecting absorber module inlets of multiple boiler units

International Nuclear Information System (INIS)

Cirillo, A.J.; Sperber, P.K.; Belavadi, V.N.; Mukherji, A.

1991-01-01

The retrofitting of scrubbers downstream of existing balanced draft boilers is often accomplished by the addition of induced draft (ID) booster fans. By creating a common plenum between the ID fans and the ID booster fans of two or more boiler-absorber trains, absorber module capacity may be shared among multiple boiler units. At Harrison Power Station, three (3) 4,900,000 lb/hour boilers (640 MWe Gross) will be linked through a common plenum. This sharing capability precludes the need to add standby module capacity, thereby saving capital dollars and keeping project critical path schedules, which typically run through absorber procurement and construction, to a minimum. Through damper placement in the ductwork cross connections, unitized boiler-absorber module operation or common plenum operation may be obtained, thus providing both operational flexibility and reliability. Additionally, open plenum operation allows the removal of an absorber unit from service, while keeping its associated boiler on line, thereby precluding 'cold starts' and maintaining overall unit availabilities. As either unitized or common plenum operation is possible with the cross connection, the furnace draft control systems of each boiler must be examined for varying load operation and trip conditions. This paper addresses the means by which to analyze such cross connection operational scenarios while maintaining compliance with furnace flame out safety guidelines, and will discuss the physical design considerations, ramifications and benefits of same, with select emphasis on what is being implemented at the Harrison Power Station

Some Novel Techniques in Operational Semantics

DEFF Research Database (Denmark)

Mosses, Peter David

2003-01-01

Several novel techniques for use in operational semantics are presented. They were developed in connection with a modular vatriant of the conventional Structural Operational Semantics framework, but can also be exploited when modularity is of no great concern. Gives a simple introduction to the m......Several novel techniques for use in operational semantics are presented. They were developed in connection with a modular vatriant of the conventional Structural Operational Semantics framework, but can also be exploited when modularity is of no great concern. Gives a simple introduction...

Optimal Load-Tracking Operation of Grid-Connected Solid Oxide Fuel Cells through Set Point Scheduling and Combined L1-MPC Control

Directory of Open Access Journals (Sweden)

Siwei Han

2018-03-01

Full Text Available An optimal load-tracking operation strategy for a grid-connected tubular solid oxide fuel cell (SOFC is studied based on the steady-state analysis of the system thermodynamics and electrochemistry. Control of the SOFC is achieved by a two-level hierarchical control system. In the upper level, optimal setpoints of output voltage and the current corresponding to unit load demand is obtained through a nonlinear optimization by minimizing the SOFC’s internal power waste. In the lower level, a combined L1-MPC control strategy is designed to achieve fast set point tracking under system nonlinearities, while maintaining a constant fuel utilization factor. To prevent fuel starvation during the transient state resulting from the output power surging, a fuel flow constraint is imposed on the MPC with direct electron balance calculation. The proposed control schemes are testified on the grid-connected SOFC model.

Integrated monitoring of multi-domain backbone connections Operational experience in the LHC optical private network

CERN Document Server

Marcu, Patricia; Fritz, Wolfgang; Yampolskiy, Mark; Hommel, Wolfgang

2011-01-01

Novel large scale research projects often require cooperation between various different project partners that are spread among the entire world. They do not only need huge computing resources, but also a reliable network to operate on. The Large Hadron Collider (LHC) at CERN is a representative example for such a project. Its experiments result in a vast amount of data, which is interesting for researchers around the world. For transporting the data from CERN to 11 data processing and storage sites, an optical private network (OPN) has been constructed. As the experiment data is highly valuable, LHC defines very high requirements to the underlying network infrastructure. In order to fulfil those requirements, the connections have to be managed and monitored permanently. In this paper, we present the integrated monitoring solution developed for the LHCOPN. We first outline the requirements and show how they are met on the single network layers. After that, we describe, how those single measurements can be comb...

Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach

Energy Technology Data Exchange (ETDEWEB)

Xia, Hui-Zhi; Li, Chao; Yang, Qing; Yang, Ming, E-mail: mingyang@ahu.edu.cn [Key Laboratory of Opto-electronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Material Science, Anhui University Hefei (China); Cao, Zhuo-Liang [School of Electronic Information Engineering, Hefei Normal University (China)

2012-08-15

The operator entanglement of two-qubit joint unitary operations is revisited. The Schmidt number, an important attribute of a two-qubit unitary operation, may have connection with the entanglement measure of the unitary operator. We find that the entanglement measure of a two-qubit unitary operators is classified by the Schmidt number of the unitary operators. We also discuss the exact relation between the operator entanglement and the parameters of the unitary operator. (author)

78 FR 18415 - Connected Vehicle Reference Implementation Architecture Workshop; Notice of Public Meeting

Science.gov (United States)

2013-03-26

... DEPARTMENT OF TRANSPORTATION Connected Vehicle Reference Implementation Architecture Workshop...) Intelligent Transportation System Joint Program Office (ITS JPO) will host a free Connected Vehicle Reference... manufacturing, developing, deploying, operating, or maintaining the connected [[Page 18416

The Operator's Diagnosis Task under Abnormal Operating Conditions in Industrial Process Plant

DEFF Research Database (Denmark)

Goodstein, L.P.; Pedersen, O.M.; Rasmussen, Jens

1974-01-01

Analysis of serious accidents in connection with the operation of technical installations demonstrate that the diagnosis task which confronts personnel under non-normal plant conditions is a critical one. This report presents a preliminary outline of characteristic traits connected with the task...... of diagnosis for use in discussions of (a) the studies which are necessary in order to formulate the operator's diagnostic procedures and (b) the possibilities which exists for supporting these procedures through appropriate data processing and display in the control system. At the same time, attempts are made...

Effects of Auxiliary-Source Connection in Multichip Power Module

DEFF Research Database (Denmark)

Li, Helong; Munk-Nielsen, Stig; Wang, Xiongfei

2017-01-01

the power loop and the gate loop like how the Kelvin-source connection does, owing to their involvement in the loop of the power source current. Three effects of the auxiliary-source connections are then analyzed, which are 1) the common source stray inductance reduction, 2) the transient drain......Auxiliary-source bond wires and connections are widely used in power modules with paralleled MOSFETs or IGBTs. This paper investigates the operation mechanism of the auxiliary-source connections in multichip power modules. It reveals that the auxiliary-source connections cannot fully decouple......-source current imbalance mitigation, and 3) the influence on the steady-state current distribution. Lastly, simulations and experimental results validate the theoretical analysis....

Connection machine: a computer architecture based on cellular automata

Energy Technology Data Exchange (ETDEWEB)

Hillis, W D

1984-01-01

This paper describes the connection machine, a programmable computer based on cellular automata. The essential idea behind the connection machine is that a regular locally-connected cellular array can be made to behave as if the processing cells are connected into any desired topology. When the topology of the machine is chosen to match the topology of the application program, the result is a fast, powerful computing engine. The connection machine was originally designed to implement knowledge retrieval operations in artificial intelligence programs, but the hardware and the programming techniques are apparently applicable to a much larger class of problems. A machine with 100000 processing cells is currently being constructed. 27 references.

Grid-Connected Inverter for Distributed Generation in Microgrid

DEFF Research Database (Denmark)

Naderipour, Amirreza; Miveh, Mohammad Reza; Guerrero, Josep M.

for power generation. DGS units can operate in parallel to the main grid or in a Microgrid (MG) mode. An MG is a discrete energy system consisting of DGSs and loads capable of operating in parallel with, or independently from, the main grid. Meanwhile, Grid-Connected Inverters (GCIs) are typically used...

On the operator equivalents

International Nuclear Information System (INIS)

Grenet, G.; Kibler, M.

1978-06-01

A closed polynomial formula for the qth component of the diagonal operator equivalent of order k is derived in terms of angular momentum operators. The interest in various fields of molecular and solid state physics of using such a formula in connection with symmetry adapted operator equivalents is outlined

Cognitive Connected Vehicle Information System Design Requirement for Safety: Role of Bayesian Artificial Intelligence

Directory of Open Access Journals (Sweden)

Ata Khan

2013-04-01

Full Text Available Intelligent transportation systems (ITS are gaining acceptance around the world and the connected vehicle component of ITS is recognized as a high priority research and development area in many technologically advanced countries. Connected vehicles are expected to have the capability of safe, efficient and eco-driving operations whether these are under human control or in the adaptive machine control mode of operations. The race is on to design the capability to operate in connected traffic environment. The operational requirements can be met with cognitive vehicle design features made possible by advances in artificial intelligence-supported methodology, improved understanding of human factors, and advances in communication technology. This paper describes cognitive features and their information system requirements. The architecture of an information system is presented that supports the features of the cognitive connected vehicle. For better focus, information processing capabilities are specified and the role of Bayesian artificial intelligence is defined for data fusion. Example applications illustrate the role of information systems in integrating intelligent technology, Bayesian artificial intelligence, and abstracted human factors. Concluding remarks highlight the role of the information system and Bayesian artificial intelligence in the design of a new generation of cognitive connected vehicle.

Quantum correction and ordering parameter for systems connected by a general point canonical transformation

International Nuclear Information System (INIS)

Yeon, Kyu Hwang; Hong, Suc Kyoung; Um, Chung In; George, Thomas F.

2006-01-01

With quantum operators corresponding to functions of the canonical variables, Schroedinger equations are constructed for systems corresponding to classical systems connected by a general point canonical transformation. Using the operator connecting quantum states between systems before and after the transformation, the quantum correction term and ordering parameter are obtained

An independent system operator's perspective on operational ramp forecasting

Energy Technology Data Exchange (ETDEWEB)

Porter, G. [New Brunswick System Operator, Fredericton, NB (Canada)

2010-07-01

One of the principal roles of the power system operator is to select the most economical resources to reliably supply electric system power needs. Operational wind power production forecasts are required by system operators in order to understand the impact of ramp event forecasting on dispatch functions. A centralized dispatch approach can contribute to a more efficient use of resources that traditional economic dispatch methods. Wind ramping events can have a significant impact on system reliability. Power systems can have constrained or robust transmission systems, and may also be islanded or have large connections to neighbouring systems. Power resources can include both flexible and inflexible generation resources. Wind integration tools must be used by system operators to improve communications and connections with wind power plants. Improved wind forecasting techniques are also needed. Sensitivity to forecast errors is dependent on current system conditions. System operators require basic production forecasts, probabilistic forecasts, and event forecasts. Forecasting errors were presented as well as charts outlining the implications of various forecasts. tabs., figs.

Decreased resting functional connectivity after traumatic brain injury in the rat.

Directory of Open Access Journals (Sweden)

Asht Mangal Mishra

Full Text Available Traumatic brain injury (TBI contributes to about 10% of acquired epilepsy. Even though the mechanisms of post-traumatic epileptogenesis are poorly known, a disruption of neuronal networks predisposing to altered neuronal synchrony remains a viable candidate mechanism. We tested a hypothesis that resting state BOLD-fMRI functional connectivity can reveal network abnormalities in brain regions that are connected to the lesioned cortex, and that these changes associate with functional impairment, particularly epileptogenesis. TBI was induced using lateral fluid-percussion injury in seven adult male Sprague-Dawley rats followed by functional imaging at 9.4T 4 months later. As controls we used six sham-operated animals that underwent all surgical operations but were not injured. Electroencephalogram (EEG-functional magnetic resonance imaging (fMRI was performed to measure resting functional connectivity. A week after functional imaging, rats were implanted with bipolar skull electrodes. After recovery, rats underwent pentyleneterazol (PTZ seizure-susceptibility test under EEG. For image analysis, four pairs of regions of interests were analyzed in each hemisphere: ipsilateral and contralateral frontal and parietal cortex, hippocampus, and thalamus. High-pass and low-pass filters were applied to functional imaging data. Group statistics comparing injured and sham-operated rats and correlations over time between each region were calculated. In the end, rats were perfused for histology. None of the rats had epileptiform discharges during functional imaging. PTZ-test, however revealed increased seizure susceptibility in injured rats as compared to controls. Group statistics revealed decreased connectivity between the ipsilateral and contralateral parietal cortex and between the parietal cortex and hippocampus on the side of injury as compared to sham-operated animals. Injured animals also had abnormal negative connectivity between the ipsilateral and

Optimization-based reactive power control in HVDC-connected wind power plants

OpenAIRE

Schönleber, Kevin; Collados Rodríguez, Carlos; Teixeira Pinto, Rodrigo; Ratés Palau, Sergi; Gomis Bellmunt, Oriol

2017-01-01

One application of high–voltage dc (HVdc) systems is the connection of remotely located offshore wind power plants (WPPs). In these systems, the offshore WPP grid and the synchronous main grid operate in decoupled mode, and the onshore HVdc converter fulfills the grid code requirements of the main grid. Thus, the offshore grid can be operated independently during normal conditions by the offshore HVdc converter and the connected wind turbines. In general, it is well known that optimized react...

Machine for welding solar cell connections

Energy Technology Data Exchange (ETDEWEB)

Lorans, D.Y.

1977-08-09

A machine for welding a connection wire over a solar cell electrode is described which comprises a base, a welding mount for the solar cell which is supported on the base, means for holding the solar cell on the welding mount, welding electrodes, means to lower the welding electrodes over the solar cell and the connection wire superimposed thereon, means for applying electric current pulses to said welding electrodes. It is characterized by the fact that it further comprises means for imparting to said mount an alternating transverse movement in relation to said base before and during the welding operation.

Going smarter in the connection of distributed generation

International Nuclear Information System (INIS)

Anaya, Karim L.; Pollitt, Michael G.

2017-01-01

This study explores and quantifies the benefits of connecting more distributed generation (DG) with and without the use of smart connections in Great Britain. We examine the impacts on different parties (Distribution Network Operators, wider society and generators). As illustration we use a specific case study. Alternative connection scenarios are proposed (with partial and full interruptible capacity quota under a mix of generation with different technology-specific curtailment levels) for integrating DG units in a constrained area of the East of England covered by the Flexible Plug and Play project. The smart (interruptible) connection option is the preferred option across all the scenarios (higher NPV/MW). The analysis of the distribution of benefits between the different parties suggests that generators capture most of the benefits while DNOs and wider society capture much less benefit. A smart connection incentive, which recreates the benefits to DNOs from an earlier losses incentive, is proposed. By contrast with other societally desirable metrics which are usually incentivised or penalised, there is currently no direct connection between more DG MWs connected and DNO incentive payments. Our proposed smart connection incentive, by charging DG for smarter connection may help to distribute more efficiently the benefits for connecting more DG. - Highlights: • Three different dimensions of going smarter to connect DG are discussed. • Benefits for connecting DG in a constrained area (FPP project) are estimated. • Different DG connection scenarios are evaluated. • Generators benefit the most and wider society the least. • A smart connection incentive may help to reallocate the benefits of DG more efficiently.

Operating characteristic analysis of a 400 mH class HTS DC reactor in connection with a laboratory scale LCC type HVDC system

Science.gov (United States)

Kim, Sung-Kyu; Kim, Kwangmin; Park, Minwon; Yu, In-Keun; Lee, Sangjin

2015-11-01

High temperature superconducting (HTS) devices are being developed due to their advantages. Most line commutated converter based high voltage direct current (HVDC) transmission systems for long-distance transmission require large inductance of DC reactor; however, generally, copper-based reactors cause a lot of electrical losses during the system operation. This is driving researchers to develop a new type of DC reactor using HTS wire. The authors have developed a 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC system and applied the HTS DC reactor to the HVDC system to investigate their operating characteristics. The 400 mH class HTS DC reactor is designed using a toroid type magnet. The HVDC system is designed in the form of a mono-pole system with thyristor-based 12-pulse power converters. In this paper, the investigation results of the HTS DC reactor in connection with the HVDC system are described. The operating characteristics of the HTS DC reactor are analyzed under various operating conditions of the system. Through the results, applicability of an HTS DC reactor in an HVDC system is discussed in detail.

Magnetic resonance imaging of anomalous pulmonary venous connections

International Nuclear Information System (INIS)

Choe, Yeon Hyeon; Lee, Heung Jae; Kim, Hak Soo; Ko, Jae Kon; Kim, Ji Eun; Han, Jae Jin

1994-01-01

We evaluated the capability of MR in the diagnosis of anomalous pulmonary venous connection (APVC). The patient group consisted of 11 total APVC and 8 partial APVC diagnosed with MR. Echocardiography was performed in all cases, cardiac angiography in 12 cases and operation in 12 cases. We compared MR findings with those of operation, echocardiography and cardiac angiography. In surgically proven 12 cases, diagnostic accuracy of preoperative MR, echocardiography and cardiac angiography was 100%, 67%, and 63%, respectively. In the remaining cases, MR findings well correlated with those of echocardiography or cardiac angiography. Stenosis of common pulmonary vein or superior vena cava was identified in 4 cases. In one patient, MR duplicated associated cortriatriatum clearly. MR is an effective modally in depicting anomalous pulmonary venous connections

Formal truncations of connected kernel equations

International Nuclear Information System (INIS)

Dixon, R.M.

1977-01-01

The Connected Kernel Equations (CKE) of Alt, Grassberger and Sandhas (AGS); Kouri, Levin and Tobocman (KLT); and Bencze, Redish and Sloan (BRS) are compared against reaction theory criteria after formal channel space and/or operator truncations have been introduced. The Channel Coupling Class concept is used to study the structure of these CKE's. The related wave function formalism of Sandhas, of L'Huillier, Redish and Tandy and of Kouri, Krueger and Levin are also presented. New N-body connected kernel equations which are generalizations of the Lovelace three-body equations are derived. A method for systematically constructing fewer body models from the N-body BRS and generalized Lovelace (GL) equations is developed. The formally truncated AGS, BRS, KLT and GL equations are analyzed by employing the criteria of reciprocity and two-cluster unitarity. Reciprocity considerations suggest that formal truncations of BRS, KLT and GL equations can lead to reciprocity-violating results. This study suggests that atomic problems should employ three-cluster connected truncations and that the two-cluster connected truncations should be a useful starting point for nuclear systems

LR: Compact connectivity representation for triangle meshes

Energy Technology Data Exchange (ETDEWEB)

Gurung, T; Luffel, M; Lindstrom, P; Rossignac, J

2011-01-28

We propose LR (Laced Ring) - a simple data structure for representing the connectivity of manifold triangle meshes. LR provides the option to store on average either 1.08 references per triangle or 26.2 bits per triangle. Its construction, from an input mesh that supports constant-time adjacency queries, has linear space and time complexity, and involves ordering most vertices along a nearly-Hamiltonian cycle. LR is best suited for applications that process meshes with fixed connectivity, as any changes to the connectivity require the data structure to be rebuilt. We provide an implementation of the set of standard random-access, constant-time operators for traversing a mesh, and show that LR often saves both space and traversal time over competing representations.

Synchronization in single-phase grid-connected photovoltaic systems under grid faults

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede

2012-01-01

The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation and stabil......The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...

High-Efficiency Photovoltaic System Using Partially-Connected DC-DC Converter

Science.gov (United States)

Uno, Masatoshi; Kukita, Akio; Tanaka, Koji

Power conversion electronics for photovoltaic (PV) systems are desired to operate as efficiently as possible to exploit the power generated by PV modules. This paper proposes a novel PV system in which a dc-dc converter is partially connected to series-connected PV modules. The proposed system achieves high power-conversion efficiency by reducing the passing power and input/output voltages of the converter. The theoretical operating principle was experimentally validated. Resultant efficiency performances of the proposed and conventional systems demonstrated that the proposed system was more efficient in terms of power conversion though the identical converter was used for the both systems.

Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet

OpenAIRE

Jain, Bhavna; Singh, Sameer; Jain, Shailendra; Nema, R. K.

2015-01-01

Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL) and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding...

Robustness of Multiple High Speed TCP CUBIC Connections Under Severe Operating Conditions

DEFF Research Database (Denmark)

Pilimon, Artur; Ruepp, Sarah Renée; Berger, Michael Stübert

2015-01-01

We study the adaptation capabilities and robustness of the high-speed TCP CUBIC algorithm. For this purpose we consider a network environment with variable and high random packet loss and a large Bandwidth-Delay product, shared by multiple heterogeneous TCP connections. The analysis is based on a...

Connectivity editing for quad-dominant meshes

KAUST Repository

Peng, Chihan

2013-08-01

We propose a connectivity editing framework for quad-dominant meshes. In our framework, the user can edit the mesh connectivity to control the location, type, and number of irregular vertices (with more or fewer than four neighbors) and irregular faces (non-quads). We provide a theoretical analysis of the problem, discuss what edits are possible and impossible, and describe how to implement an editing framework that realizes all possible editing operations. In the results, we show example edits and illustrate the advantages and disadvantages of different strategies for quad-dominant mesh design. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and John Wiley & Sons Ltd.

International comparison of requirements for connection of wind turbines to power systems

Energy Technology Data Exchange (ETDEWEB)

Jauch, C. [Risoe National Lab., Roskilde (Denmark). Dept. of Wind Energy; Matevosyan, J.; Ackermann, T. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Electrical Engineering; Bolik, S. [Vestas Wind Systems A/S, Ringkoebing (Denmark)

2005-07-01

Power production from wind turbines has increased considerably during the last decade. Therefore today's wind turbines, which are typically set up in wind farms, have a significant influence on the operation of power systems. The efficient and secure operation of power systems is supported by grid codes, which are sets of requirements for all network users (suppliers, customers, etc.). In Europe, several transmission network operators have introduced special grid connection requirements for wind farms. These requirements are mainly based on existing grid codes, initially written for conventional power plants usually equipped with synchronous generators. This article presents a comparison of grid connection requirements for wind farms issued, or proposed as a draft, by transmission network operators in Denmark, Sweden, Germany, Scotland and Ireland. (author)

Enhanced Control for Improving the Operation of Grid-Connected Power Converters under Faulty and Saturated Conditions

Directory of Open Access Journals (Sweden)

Mahdi Shahparasti

2018-02-01

Full Text Available In renewable energy based systems Grid-Connected Voltage Source Converters (GC-VSC are used in many applications as grid-feeding converters, which transfer the power coming from the renewable energy sources to the grid. In some cases, the operation of GC-VSC may become unstable or uncontrollable due to, among others: a grid fault or an inappropriate current-power reference, that give rise to fast electrical transients or a saturation of the controller. In this paper, an improved control scheme is proposed to enhance the controllability of GC-VSC in all these situations. This solution consists of two parts, on the one hand a new Proportional-Resonant (PR controller with anti-windup capability to be used as current controller, and secondly a new current/power reference modifier, which defines the suitable reactive current/power reference to keep the system stable. It is worth to mention that the proposed scheme does not need information about the grid parameters as it only uses the converter current, and the voltage at the capacitors of Inductor-Capacitor (LC output filter.

Battery impedance spectroscopy using bidirectional grid connected ...

Indian Academy of Sciences (India)

Shimul Kumar Dam

Keywords. Impedance spectroscopy; grid connection; battery converter; state of charge; health monitoring. 1. Introduction .... the load should be within the safe range of operation specified by the ... A split capacitor damping scheme is adopted here as shown in ...... spectroscopy testing on the Advanced Technology Devel-.

Autonomous Operation of Low Voltage Microgrids

Directory of Open Access Journals (Sweden)

Irena Wasiak

2014-12-01

Full Text Available The article describes the possibilities of LV microgrids operation in the island mode. Control strategies of energy sources connected to the grid by means of invertors are discussed, either for a microgrid connected to the supplying network or during the island mode operation. The presented results of research were conducted at the Laboratory of Distributed Generation at Lodz University of Technology. The study was performed for two variants of reference voltage source: the battery storage and microturbine respectively.

Internet services for planning distributed generation connections

Energy Technology Data Exchange (ETDEWEB)

Curry, D.; Morgan, A.; Barbier, C.; Reay, P.

2005-07-01

The required publication by distributed network operators (DNOs) of details of the current state of their network systems and future planned developments in the form of Long Term Development Statements (LTDS) are discussed. This project aims to increase the usefulness of the information in the LTDS by making it available on the internet and by providing an initial assessment of connection opportunities and the possibility of viewing existing renewable generation projects. The services developed covered data loading, data visualisation, security, connection assessment, reporting, and generation site registration. The benefits of an electronic version of the LTDS are highlighted.

Mitigation of Harmonics in Grid-Connected and Islanded Microgrids via Virtual Admittances and Impedances

DEFF Research Database (Denmark)

Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

2017-01-01

Optimization of the islanded and grid-connected operation of microgrids is important to achieve a high degree of reliability. In this paper, the authors consider the effect of current harmonics in single phase microgrids during both modes of operation. A detailed analysis of the effect of the out......Optimization of the islanded and grid-connected operation of microgrids is important to achieve a high degree of reliability. In this paper, the authors consider the effect of current harmonics in single phase microgrids during both modes of operation. A detailed analysis of the effect...... of the output impedance of the considered primary control loops on the harmonic output of the considered voltage source inverters is initially carried out. A virtual admittance loop is proposed to attenuate the current harmonic output in grid-connected operation that is generated due to the grid voltage...... distortion present at the point of common coupling (PCC) and due to local non-linear loads. This paper also considers the harmonic current sharing and resulting voltage harmonics at the PCC during islanded operation of the microgrid. A capacitive virtual impedance loop was implemented to improve the harmonic...

Passivity Enhancement in RES Based Power Plant with Paralleled Grid-Connected Inverters

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2016-01-01

Harmonic instability is threatening the operation of power plants with multiple grid connected converters in parallel. To analyze and improve the stability of the grid connected converters, the passivity of the output admittance converters is first analyzed in this paper. It is shown that the non-passivity...

Some classes of analytic functions involving Noor integral operator

Science.gov (United States)

Patel, J.; Cho, N. E.

2005-12-01

The object of the present paper is to investigate some inclusion properties of certain subclasses of analytic functions defined by using the Noor integral operator. The integral preserving properties in connection with the operator are also considered. Relevant connections of the results presented here with those obtained in earlier works are pointed out.

Modelling, Analysis and Control of DC-connected Wind Farms to Grid

DEFF Research Database (Denmark)

Iov, Florin; Sørensen, Poul; Hansen, Anca Daniela

2006-01-01

wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled.  However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...... of the active stall wind farms to the grid can provide these features and also maximize the produced power especially at low wind speeds by using variable voltage/frequency for the wind farm. The focus in this paper is in studying the variable speed operation for the active stall wind farms using a voltage...

Autonomous and Connected Vehicles: A Law Enforcement Primer

Science.gov (United States)

2015-12-01

parallel or back-in parking in Toyota Prius vehicles is one example currently marketed and in operation in the United States.275 Testing is on-going...ownership in a connected environment.276 275 “All-New Third Generation Toyota Prius Raises the Bar for...design-patterns-and- operational-concepts-tasks-28-42-115/. Toyota . “All-New Third Generation Toyota Prius Raises the Bar for Hybrid Vehicles— Again

Unified connected theory of few-body reaction mechanisms in N-body scattering theory

Science.gov (United States)

Polyzou, W. N.; Redish, E. F.

1978-01-01

A unified treatment of different reaction mechanisms in nonrelativistic N-body scattering is presented. The theory is based on connected kernel integral equations that are expected to become compact for reasonable constraints on the potentials. The operators T/sub +-//sup ab/(A) are approximate transition operators that describe the scattering proceeding through an arbitrary reaction mechanism A. These operators are uniquely determined by a connected kernel equation and satisfy an optical theorem consistent with the choice of reaction mechanism. Connected kernel equations relating T/sub +-//sup ab/(A) to the full T/sub +-//sup ab/ allow correction of the approximate solutions for any ignored process to any order. This theory gives a unified treatment of all few-body reaction mechanisms with the same dynamic simplicity of a model calculation, but can include complicated reaction mechanisms involving overlapping configurations where it is difficult to formulate models.

Connected vehicle pilot deployment program phase 1, security management operational concept : ICF/Wyoming.

Science.gov (United States)

2016-03-14

The Wyoming Department of Transportations (WYDOT) Connected Vehicle (CV) Pilot Deployment Program is intended to develop a suite of applications that utilize vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) communication technology to ...

Passivity Enhancement in Renewable Energy Source Based Power Plant With Paralleled Grid-Connected VSIs

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

Harmonic instability is threatening the operation of renewable energy based power plants where multiple gridconnected VSIs are connected in parallel. To analyze and improve the stability of the grid-connected VSIs, the real part of the output admittance of the VSIs is first investigated......-connected VSIs can improve the stability of the renewable power plant....

The impact analysis of the connecting pipe length and diameter on the operation of a piston hybrid power machine of positive displacement with gas suction capacity

Science.gov (United States)

Shcherba, V. E.; Grigoriev, A. V.; Averyanov, G. S.; Surikov, V. I.; Vedruchenko, V. P.; Galdin, N. S.; Trukhanova, D. A.

2017-08-01

The article analyzes the impact of the connecting liquid pipe length and diameter on consumables and power characteristics of the piston hybrid power machine with gas suction capacity. The following operating characteristics of the machine were constructed and analyzed: the average height of the liquid column in the jacket space; instantaneous velocity and height of the liquid column in the jacket space; the relative height of the liquid column in the jacket space; volumetric efficiency; indicator isothermal efficiency; flowrate in the pump section; relative pressure losses during suction; relative flowrate. The dependence of the instantaneous pressure in the work space and the suction space of the compressor section on the rotation angle of the crankshaft is determined for different values of the length and diameter of the connecting pipeline.

Full-load converter connected asynchronous generators for MW class wind turbines

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, Vladislav

2005-06-15

Wind turbines equipped with full-load converter-connected asynchronous generators are a known concept. These have rating up to hundreds of kW and are a feasible concept for MW class wind turbines and may have advantages when compared to conventional wind turbines with directly connected generators. The concept requires the use of full-scale frequency converters, but the mechanical gearbox is smaller than in conventional wind turbines of the same rating. Application of smaller gearbox may reduce the no-load losses in the wind turbines, which is why such wind turbines with converter connected generators may start operation at a smaller wind speed. Wind turbines equipped with such converted connected asynchronous generators are pitch-controlled and variable-speed. This allows better performance and control. The converter control may be applied to support the grid voltage at short-circuit faults and to improve the fault-ride-through capability of the wind turbines, which makes the concepts relevant for large wind farms. The Danish transmission system operator Energinet-DK has implemented the general model of wind turbines equipped with converter connected asynchronous generators with the simulation tool Powerfactory (DlgSilent). The article presents Energinet-DK's experience of modeling this feasible wind turbine concept. (Author)

grid-connected photovoltaic system design for local government

African Journals Online (AJOL)

user

wind power and has durability of more than twenty five years with a very minimal .... enhance energy yield of grid connected PV power plant by naturally catching .... cause it to operate at maximum power point irrespective of changing weather ...

Differential operators and W-algebra

International Nuclear Information System (INIS)

Vaysburd, I.; Radul, A.

1992-01-01

The connection between W-algebras and the algebra of differential operators is conjectured. The bosonized representation of the differential operator algebra with c=-2n and all the subalgebras are examined. The degenerate representations and null-state classifications for c=-2 are presented. (orig.)

Assessment of a new seasonal to inter-annual operational Great Lakes water supply, water levels, and connecting channel flow forecasting system

Science.gov (United States)

Gronewold, A.; Fry, L. M.; Hunter, T.; Pei, L.; Smith, J.; Lucier, H.; Mueller, R.

2017-12-01

The U.S. Army Corps of Engineers (USACE) has recently operationalized a suite of ensemble forecasts of Net Basin Supply (NBS), water levels, and connecting channel flows that was developed through a collaboration among USACE, NOAA's Great Lakes Environmental Research Laboratory, Ontario Power Generation (OPG), New York Power Authority (NYPA), and the Niagara River Control Center (NRCC). These forecasts are meant to provide reliable projections of potential extremes in daily discharge in the Niagara and St. Lawrence Rivers over a long time horizon (5 years). The suite of forecasts includes eight configurations that vary by (a) NBS model configuration, (b) meteorological forcings, and (c) incorporation of seasonal climate projections through the use of weighting. Forecasts are updated on a weekly basis, and represent the first operational forecasts of Great Lakes water levels and flows that span daily to inter-annual horizons and employ realistic regulation logic and lake-to-lake routing. We will present results from a hindcast assessment conducted during the transition from research to operation, as well as early indications of success rates determined through operational verification of forecasts. Assessment will include an exploration of the relative skill of various forecast configurations at different time horizons and the potential for application to hydropower decision making and Great Lakes water management.

Distributed Generation using Indirect Matrix Converter in Boost Operating Mode

DEFF Research Database (Denmark)

Liu, Xiong; Loh, Poh Chiang; Wang, Peng

2011-01-01

, reverse power flow operation of IMC can be implemented to meet voltage boost requirement, where the input ac source is connected to the converter's voltage source side and the output utility grid or load is connected to the current source side. This paper proposes control schemes of IMC under reverse...... power flow operation for both grid-connected and isolated modes with distributed generation suggested as a potential application. In grid-connected mode, the commanded power must be extracted from the input ac source to the grid, in addition to guarantee sinusoidal input/output waveforms, unity input...

Interharmonics from Grid-Connected PV Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

2017-01-01

As the penetration level of grid-connected Photovoltaic (PV) systems increases, the power quality is one of the major concerns for system operators and the demands are becoming even stricter. The impact of interharmonics on the grid has been acknowledged in recent research when considering a large......-scale adoption of PV inverters. However, the origins of interharmonics remain unclear. Thus, this paper performs tests on a commercial PV inverter to explore interharmonic generation and more important investigates the mechanism of interharmonic emission. The investigation reveals that the perturbation...... of the solutions. Simulation results indicate that the constant-voltage MPPT method is the most suitable solution to the mitigation of interharmonics introduced by the MPPT operation, as it avoids the perturbation in the PV voltage during operation....

[Internal fixation treatment of multiple rib fractures with absorbable rib-connecting-pins under epidural anesthesia].

Science.gov (United States)

Liu, Jinliang; Li, Keyao; Ju, Zhenlong; Bai, Yan

2011-03-01

To study the indications, methods and experience of absorbable rib-connecting-pins fixation in the treatment of multiple rib fractures. 52 cases with multiple rib fractures were performed internal fixation with absorbable rib-connecting-pins under epidural anesthesia. All cases were followed up for 1 to 12 months, with an average of 5 months. All fractures were achieved healing in 3 to 6 months after the operation and were not found chest wall deformity. Absorbable rib-connecting-pins fixation is a simple and effective method and worthies recommending to perform operation for the appropriate cases with multiple rib fractures.

Banding of connection standards for distributed generation

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-05-04

This report presents the views of distributed network operators (DNOs), developers, equipment manufacturers and consultants on the current banding of distributed generation in terms of connection standards and recommendations. The Documents ER G59/1, ER G75/1, ER G83/1 and ETR 113/1 covering recommendations for the connection of embedded generating plant to distribution systems and guidance notes for the protection of embedded generating plant are examined. The way in which the recommendations are applied in practice is investigated. Multiple distribution generator installations, fault ride through, and banding are considered as well as both protection required and maximum generator sizes at respective voltage levels.

Performance evaluation of 10 MW grid connected solar photovoltaic power plant in India

OpenAIRE

B. Shiva Kumar; K. Sudhakar

2015-01-01

The growing energy demand in developing nations has triggered the issue of energy security. This has made essential to utilize the untapped potential of renewable resources. Grid connected PV systems have become the best alternatives in renewable energy at large scale. Performance analysis of these grid connected plants could help in designing, operating and maintenance of new grid connected systems. A 10 MW photovoltaic grid connected power plant commissioned at Ramagundam is one of the larg...

The spin-statistics connection in classical field theory

International Nuclear Information System (INIS)

Morgan, J A

2006-01-01

The spin-statistics connection is obtained for a simple formulation of a classical field theory containing even and odd Grassmann variables. To that end, the construction of irreducible canonical realizations of the rotation group corresponding to general causal fields is reviewed. The connection is obtained by imposing local commutativity on the fields and exploiting the parity operation to exchange spatial coordinates in the scalar product of classical field evaluated at one spatial location with the same field evaluated at a distinct location. The spin-statistics connection for irreducible canonical realizations of the Poincare group of spin j is obtained in the form: classical fields and their conjugate momenta satisfy fundamental field-theoretic Poisson bracket relations for 2j even and fundamental Poisson antibracket relations for 2j odd

Operator theory

CERN Document Server

2015-01-01

A one-sentence definition of operator theory could be: The study of (linear) continuous operations between topological vector spaces, these being in general (but not exclusively) Fréchet, Banach, or Hilbert spaces (or their duals). Operator theory is thus a very wide field, with numerous facets, both applied and theoretical. There are deep connections with complex analysis, functional analysis, mathematical physics, and electrical engineering, to name a few. Fascinating new applications and directions regularly appear, such as operator spaces, free probability, and applications to Clifford analysis. In our choice of the sections, we tried to reflect this diversity. This is a dynamic ongoing project, and more sections are planned, to complete the picture. We hope you enjoy the reading, and profit from this endeavor.

Non-Archimedean analogues of orthogonal and symmetric operators

International Nuclear Information System (INIS)

Albeverio, S; Bayod, J M; Perez-Garsia, C; Khrennikov, A Yu; Cianci, R

1999-01-01

We study orthogonal and symmetric operators on non-Archimedean Hilbert spaces in connection with the p-adic quantization. This quantization describes measurements with finite precision. Symmetric (bounded) operators on p-adic Hilbert spaces represent physical observables. We study the spectral properties of one of the most important quantum operators, namely, the position operator (which is represented on p-adic Hilbert L 2 -space with respect to the p-adic Gaussian measure). Orthogonal isometric isomorphisms of p-adic Hilbert spaces preserve the precision of measurements. We study properties of orthogonal operators. It is proved that every orthogonal operator on non-Archimedean Hilbert space is continuous. However, there are discontinuous operators with dense domain of definition that preserve the inner product. There exist non-isometric orthogonal operators. We describe some classes of orthogonal isometric operators on finite-dimensional spaces. We study some general questions in the theory of non-Archimedean Hilbert spaces (in particular, general connections between the topology, norm and inner product)

Family of commuting operators for the totally asymmetric exclusion process

International Nuclear Information System (INIS)

Golinelli, O; Mallick, K

2007-01-01

The algebraic structure underlying the totally asymmetric exclusion process is studied by using the Bethe Ansatz technique. From the properties of the algebra generated by the local jump operators, we explicitly construct the hierarchy of operators (called generalized Hamiltonians) that commute with the Markov operator. The transfer matrix, which is the generating function of these operators, is shown to represent a discrete Markov process with long-range jumps. We give a general combinatorial formula for the connected Hamiltonians obtained by taking the logarithm of the transfer matrix. This formula is proved using a symbolic calculation program for the first ten connected operators

Observer's Report - Okinawa Operation

National Research Council Canada - National Science Library

Todd, W. N., Jr

1945-01-01

... for temporary duty in connection with the Okinawa Operation. By verbal agreement between observers, it was decided that each officer would cover certain activities and thus have a complete coverage without duplication...

Grid-Connected Photovoltaic System with Active Power Filtering Functionality

Directory of Open Access Journals (Sweden)

Joaquín Vaquero

2018-01-01

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

Discerning connectivity from dynamics in climate networks

Czech Academy of Sciences Publication Activity Database

Paluš, Milan; Hartman, David; Hlinka, Jaroslav; Vejmelka, Martin

2011-01-01

Roč. 18, č. 5 (2011), s. 751-763 ISSN 1023-5809 R&D Projects: GA ČR GCP103/11/J068 Institutional research plan: CEZ:AV0Z10300504 Keywords : complex networks * climate dynamics * connectivity * North Atlantic Oscillation * solar activity Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.597, year: 2011

Energy-efficient three-phase bidirectional converter for grid-connected storage applications

International Nuclear Information System (INIS)

Colmenar-Santos, Antonio; Linares-Mena, Ana-Rosa; Velázquez, Jesús Fernández; Borge-Diez, David

2016-01-01

Highlights: • Storage control system developed based on AC DC three phase bidirectional converter. • Bidirectional AC DC converter for storage integration into distribution grids. • Efficiencies over 98% for values over 30% of the bidirectional converter rated power. • Sensitivity analysis of the parameters set by the transmission system operator. • Low-cost option for control and integration of new grid-connected storage systems. - Abstract: Grid connected energy storage systems are expected to play an essential role in the development of Smart Grids, providing, among other benefits, ancillary services to power grids. It is therefore crucial to design and develop control and conversion systems that represent the key instrument where intelligence for decision-making is applied, in order to validate and ensure its optimal operation as part and parcel of the electrical system. The present research describes the design and development of a battery energy storage system based on an AC-DC three-phase bidirectional converter capable of operating either in charge mode to store electrical energy, or in discharge mode to supply load demands. The design is modelled with MATLAB® Simulink® environment in order to evaluate the performance during load variations. Moreover, the assessment is complemented by a global sensitivity analysis for variations in the operating parameters set by the transmission system operator. The effectiveness of the simulation is confirmed by implementing the system and carrying out grid connection tests, obtaining efficiencies over 98% for values over the 30% of the bidirectional converter rated power.

Automatic radiation measuring system connected with GPS

International Nuclear Information System (INIS)

Tanigaki, Minoru

2014-01-01

The most serious nuclear disaster in Japan has broken out at Fukushima Daiichi Nuclear Power Plant due to Great East Japan Earthquake. Prompt and exact mapping of the contamination is of great importance for radiation protection and for the environment restoration. We have developed radiation survey systems KURAMA and KURAMA-2 for rapid and exact measurement of radiation dose distribution. The system is composed of a mobile radiation monitor and the computer in office which is for the storage and visualization of the data. They are connected with internet and are operated for continuous radiation measurement while the monitor is moving. The mobile part consists of a survey meter, an interface to transform the output of the survey meter for the computer, a global positioning system, a computer to process the data for connecting to the network, and a mobile router. Thus they are effective for rapid mapping of the surface contamination. The operation and the performance of the equipment at the site are presented. (J.P.N.)

Operator interface programs for KSTAR operation

International Nuclear Information System (INIS)

Lee, Sangil; Park, Mikyung; Park, Jinseop; Na, Hoonkyun; Kwon, M.

2013-01-01

Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system

Operator interface programs for KSTAR operation

Energy Technology Data Exchange (ETDEWEB)

Lee, Sangil, E-mail: leesi@nfri.re.kr; Park, Mikyung, E-mail: mkpark@nfri.re.kr; Park, Jinseop, E-mail: linupark@nfri.re.kr; Na, Hoonkyun, E-mail: hkna@nfri.re.kr; Kwon, M., E-mail: kwonm@nfri.re.kr

2013-11-15

Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system.

Wideband energy harvesting based on mixed connection of piezoelectric oscillators

Science.gov (United States)

Wu, P. H.; Chen, Y. J.; Li, B. Y.; Shu, Y. C.

2017-09-01

An approach for wideband energy harvesting together with power enhancement is proposed by integrating multiple piezoelectric oscillators with mixed parallel-series connection. This gives rise to the feasibility of shifting the operation frequency band to the dominant frequency domain of ambient excitations. There are two types of connection patterns discussed here: the p-type (s-type) is the parallel (series) connection of all sets of oscillators where some of them may be connected in series (parallel). In addition, the standard interface circuit used for electric rectification is adopted here. The analytic estimates of output power are derived and explicitly expressed in terms of different matrix formulations for these two connection patterns. They are subsequently validated and are found in good agreement with numerical simulations and experimental observations. Finally, the experimental results from the mixed connection of 4 piezoelectric oscillators show that the peak power of each array is about 3.4 times higher than that generated by a single piezoelectric oscillator. In addition, the bandwidth of the array capable of switching connection patterns is around 2.8 times wider than that based on a single array configuration. Hence, the effective bandwidth is enlarged without the loss of peak power.

Optical Fiber Connection Navigation System Using Visible Light Communication in Central Office with Economic Evaluation

Science.gov (United States)

Waki, Masaki; Uruno, Shigenori; Ohashi, Hiroyuki; Manabe, Tetsuya; Azuma, Yuji

We propose an optical fiber connection navigation system that uses visible light communication for an integrated distribution module in a central office. The system realizes an accurate database, requires less skilled work to operate and eliminates human error. This system can achieve a working time reduction of up to 88.0% compared with the conventional work without human error for the connection/removal of optical fiber cords, and is economical as regards installation and operation.

Connectivity, topology and dynamics in climate networks

Czech Academy of Sciences Publication Activity Database

Paluš, Milan; Hartman, David; Hlinka, Jaroslav; Vejmelka, Martin

2012-01-01

Roč. 14, - (2012), s. 8397 ISSN 1607-7962. [European Geosciences Union General Assembly 2012. 22.04.2012-27.04.2012, Vienna] R&D Projects: GA ČR GCP103/11/J068 Institutional support: RVO:67985807 Keywords : complex networks * climate network * connectivity * entropy rate * El Nino Southern Oscillation * North Atlantic Oscillation Subject RIV: BB - Applied Statistics, Operational Research

Design optimization of grid-connected PV inverters

DEFF Research Database (Denmark)

Koutroulis, Eftichios; Blaabjerg, Frede

2011-01-01

The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

Interior operators and topological connectedness | Castellini ...

African Journals Online (AJOL)

A categorical notion of interior operator is used in topology to define connectedness and disconnectedness with respect to an interior operator. A commutative diagram of Galois connections is used to show a relationship between these notions and Arhangelskii and Wiegandt's notions of connectedness and ...

Operational quantum theory without predefined time

International Nuclear Information System (INIS)

Oreshkov, Ognyan; Cerf, Nicolas J

2016-01-01

The standard formulation of quantum theory assumes a predefined notion of time. This is a major obstacle in the search for a quantum theory of gravity, where the causal structure of space-time is expected to be dynamical and fundamentally probabilistic in character. Here, we propose a generalized formulation of quantum theory without predefined time or causal structure, building upon a recently introduced operationally time-symmetric approach to quantum theory. The key idea is a novel isomorphism between transformations and states which depends on the symmetry transformation of time reversal. This allows us to express the time-symmetric formulation in a time-neutral form with a clear physical interpretation, and ultimately drop the assumption of time. In the resultant generalized formulation, operations are associated with regions that can be connected in networks with no directionality assumed for the connections, generalizing the standard circuit framework and the process matrix framework for operations without global causal order. The possible events in a given region are described by positive semidefinite operators on a Hilbert space at the boundary, while the connections between regions are described by entangled states that encode a nontrivial symmetry and could be tested in principle. We discuss how the causal structure of space-time could be understood as emergent from properties of the operators on the boundaries of compact space-time regions. The framework is compatible with indefinite causal order, timelike loops, and other acausal structures. (paper)

LHCb connects its pipes

CERN Multimedia

2006-01-01

Two weeks ago the first beryllium section of the LHCb beam vacuum chamber was installed. This three-day operation, after requiring lengthy preparation work, demanded patience and precision as the first of four sections of the beampipe was connected to the vertex locator (VeLo) vacuum vessel. The AT-VAC Group with the collaboration of PH/LBD, including Gloria Corti, Tatsuya Nakada, Patrice Mermet, Delios Ramos, Frans Mul, Bruno Versollato, Bernard Corajod, and Raymond Veness. (Not pictured: Adriana Rossi and Laurent Bouvet) This first installed section is composed of a nearly two-metre long conical tube of one-millimetre thick beryllium and of a thin spherical-shaped window, 800 millimeter diameter, made of an aluminum alloy, and has the appearance of a mushroom lying on its side. The window is connected to the conical part of the beampipe through an aluminum alloy bellow, which is needed to allow for mechanical alignment once the assembly is installed. Beryllium was chosen as the material for 12 m of the 19...

Nordic Model of Subregional Co-Operation

Directory of Open Access Journals (Sweden)

Grzela Joanna

2017-12-01

Full Text Available Nordic co-operation is renowned throughout the world and perceived as the collaboration of a group of countries which are similar in their views and activities. The main pillars of the Nordic model of co-operation are the tradition of constitutional principles, activity of public movements and organisations, freedom of speech, equality, solidarity, and respect for the natural environment. In connection with labour and entrepreneurship, these elements are the features of a society which favours efficiency, a sense of security and balance between an individual and a group. Currently, the collaboration is a complex process, including many national, governmental and institutional connections which form the “Nordic family”.

Finding significantly connected voxels based on histograms of connection strengths

DEFF Research Database (Denmark)

Kasenburg, Niklas; Pedersen, Morten Vester; Darkner, Sune

2016-01-01

We explore a new approach for structural connectivity based segmentations of subcortical brain regions. Connectivity based segmentations are usually based on fibre connections from a seed region to predefined target regions. We present a method for finding significantly connected voxels based...... on the distribution of connection strengths. Paths from seed voxels to all voxels in a target region are obtained from a shortest-path tractography. For each seed voxel we approximate the distribution with a histogram of path scores. We hypothesise that the majority of estimated connections are false-positives...... and that their connection strength is distributed differently from true-positive connections. Therefore, an empirical null-distribution is defined for each target region as the average normalized histogram over all voxels in the seed region. Single histograms are then tested against the corresponding null...

Technical guide to the connection of generation to the distribution network

Energy Technology Data Exchange (ETDEWEB)

Jarrett, K.; Hedgecock, J.; Gregory, R.; Warham, T.

2003-07-01

This guide provides a 'route map' of the processes of getting a generation scheme connected to the network and is intended to help developers of any form of distributed generation connected to the UK's local electricity networks, eg: renewable energy schemes; waste-to-energy schemes; on-site generation and combined heat and power (CHP) schemes; and peak lopping schemes using back-up generators. Where necessary, the guide distinguishes between arrangements that apply in Scotland and those that apply in England and Wales. The guide aims to: provide background information about the electricity industry; highlight common technical issues that arise during connection negotiation and their implications for distribution network operators (DNOs) and developers; examine the main factors affecting connection costs and timescales for achieving connections; and identify the different types of contracts relating to connection. The report considers the connection process, the connection application process and timescales, costs and charges, competition in connection, the structure of the UK electricity industry, the statutory framework, the effects of distributed generation of the distribution system, earthing and protection design, safety issues and DNO network information. It includes a glossary, checklists, useful contact details and information about standards and other useful documents.

Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet

Directory of Open Access Journals (Sweden)

Bhavna Jain

2015-01-01

Full Text Available Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding and grid connected mode as well. In particular, a proper monitoring and control algorithm is required for transition between the modes. A wavelet based energy function is used for detection of grid disturbances as well as recovery of grid so that transition between the modes is made. To obtain good power quality LCL filter is used to reduce ripples. PLL is used for synchronization whenever mode changes from stand-alone to grid connected. Simulation results from a 10 kW wind energy conversion system are included to show the usefulness of the proposed methods. The control method is tested by generated gate pulses for single phase bridge inverter using field programmable gate array (FPGA.

Online Variable Topology-Type Photovoltaic Grid-Connected Inverter

DEFF Research Database (Denmark)

Wu, Fengjiang; Sun, Bo; Duan, Jiandong

2015-01-01

In photovoltaic (PV) grid-connected generation system, the key focus is how to expand the generation range of the PV array and enhance the total efficiency of the system. This paper originally derived expressions of the total loss and grid current total harmonics distortions of cascaded inverter...... and H-bridge inverter under the conditions of variable output voltage and power of the PV array. It is proved that, compared with the H-bridge inverter, the operation range of the cascaded inverter is wider, whereas the total loss is larger. Furthermore, a novel online variable topology-type grid......-connected inverter is proposed. A bidirectional power switch is introduced into the conventional cascaded inverter to connect the negative terminals of the PV arrays. When the output voltages of the PV arrays are lower, the proposed inverter works under cascaded inverter mode to obtain wider generation range. When...

Supplantation of Mental Operations on Graphs

Science.gov (United States)

Vogel, Markus; Girwidz, Raimund; Engel, Joachim

2007-01-01

Research findings show the difficulties younger students have in working with graphs. Higher mental operations are necessary for a skilled interpretation of abstract representations. We suggest connecting a concrete representation of the modeled problem with the related graph. The idea is to illustrate essential mental operations externally. This…

About Connections

Directory of Open Access Journals (Sweden)

Kathleen S Rockland

2015-05-01

Full Text Available Despite the attention attracted by connectomics, one can lose sight of the very real questions concerning What are connections? In the neuroimaging community, structural connectivity is ground truth and underlying constraint on functional or effective connectivity. It is referenced to underlying anatomy; but, as increasingly remarked, there is a large gap between the wealth of human brain mapping and the relatively scant data on actual anatomical connectivity. Moreover, connections have typically been discussed as pairwise, point x projecting to point y (or: to points y and z, or more recently, in graph theoretical terms, as nodes or regions and the interconnecting edges. This is a convenient shorthand, but tends not to capture the richness and nuance of basic anatomical properties as identified in the classic tradition of tracer studies. The present short review accordingly revisits connectional weights, heterogeneity, reciprocity, topography, and hierarchical organization, drawing on concrete examples. The emphasis is on presynaptic long-distance connections, motivated by the intention to probe current assumptions and promote discussions about further progress and synthesis.

ABOUT TECHNOLOGY FEATURES OF ASSEMBLING OF RUBBER-METAL CONNECTIONS

Directory of Open Access Journals (Sweden)

VODOLAZSKAYA Nataliia

2016-11-01

Full Text Available Assembly process is important technological operation when manufacturing products and equipment, and also it uses during operation and repairs different type of implements The modern automated manufacture cannot be presented without the existence of machines continuously action, in particular of belt conveyors. One of its basic units is the belt and ways of its connection. Usually, the quantity of cracks of belt joints is equal to (reaches 62 within 1 km of a belt of conveyor during 10 years upon condition that equipment works in a difficult cycle of mines. One of the basic operation problems of these transports is the rupture of the joint of a belt as emergency idle times of conveyors makes approximately of 10 % of working hours, and planned stops on manufacturing or repair of joints - to of 20 %. Therefore, now research in the field of maintenance of qualitative manufacturing of a joint of conveyor belts are of interest at this time. The way of using of rubber-metal connections assembling with help self-cutting screws is offered. This allows increasing durability’s characteristics of joints of the conveyor belt

Ripple gate drive circuit for fast operation of series connected IGBTs

Science.gov (United States)

Rockot, Joseph H.; Murray, Thomas W.; Bass, Kevin C.

2005-09-20

A ripple gate drive circuit includes a plurality of transistors having their power terminals connected in series across an electrical potential. A plurality of control circuits, each associated with one of the transistors, is provided. Each control circuit is responsive to a control signal and an optical signal received from at least one other control circuit for controlling the conduction of electrical current through the power terminals of the associated transistor. The control circuits are responsive to a first state of the control circuit for causing each transistor in series to turn on sequentially and responsive to a second state of the control signal for causing each transistor in series to turn off sequentially.

S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application

DEFF Research Database (Denmark)

Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran

2016-01-01

This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal...... size, low cost, flexible grounding configuration and higher efficiency. The operating principle and analysis of the proposed circuit are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The results obtained...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems....

Fluid logic control circuit operates nutator actuator motor

Science.gov (United States)

1966-01-01

Fluid logic control circuit operates a pneumatic nutator actuator motor. It has no moving parts and consists of connected fluid interaction devices. The operation of this circuit demonstrates the ability of fluid interaction devices to operate in a complex combination of series and parallel logic sequence.

Analysis of step-up transformer tap change on the quantities at the point of connection to transmission grid

Directory of Open Access Journals (Sweden)

Đorđević Dragan

2017-01-01

Full Text Available The analysis of a step-up transformer tap change on the quantities at the point of connection to the transmission grid is presented in this paper. The point of connection of generator TENT A6 has been analyzed, and a detailed model of this generator is available in software package DIgSILENT Power Factory. The comparison between the effect of a step-up transformer tap change on the quantities at the point of connection during automatic and manual operation of voltage regulator has been conducted. In order to conduct the analysis of the manual operation of the voltage regulator, the comparison between the different methods of modeling of these modes has been performed. Several generator operating points, selected in order to represent the need for tap change, have been analyzed. Also, previously mentioned analyses have been performed taking into account the voltage-reactive stiffness at the point of connection.

Dynamic connectivity algorithms for Monte Carlo simulations of the random-cluster model

International Nuclear Information System (INIS)

Elçi, Eren Metin; Weigel, Martin

2014-01-01

We review Sweeny's algorithm for Monte Carlo simulations of the random cluster model. Straightforward implementations suffer from the problem of computational critical slowing down, where the computational effort per edge operation scales with a power of the system size. By using a tailored dynamic connectivity algorithm we are able to perform all operations with a poly-logarithmic computational effort. This approach is shown to be efficient in keeping online connectivity information and is of use for a number of applications also beyond cluster-update simulations, for instance in monitoring droplet shape transitions. As the handling of the relevant data structures is non-trivial, we provide a Python module with a full implementation for future reference.

Generation-Side Power Scheduling in a Grid-Connected DC Microgrid

DEFF Research Database (Denmark)

Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Meng, Lexuan

2015-01-01

In this paper, a constrained mixed-integer programming model for scheduling the active power supplied by the generation units in storage-based DC microgrids is presented. The optimization problem minimizes operating costs taking into account a two-stage mode operation of the energy storage system...... so that a more accurate model for optimization of the microgrid operation can be obtained. The model is used in a particular grid-connected DC microgrid that includes two renewable energy sources and an energy storage system which supply a critical load. The results of the scheduling process...

Concept of Operations for Road Weather Connected Vehicle and Automated Vehicle Applications

Science.gov (United States)

2017-05-21

Weather has a significant impact on the operations of the nation's roadway system year round. These weather events translate into changes in traffic conditions, roadway safety, travel reliability, operational effectiveness and productivity. It is, th...

Modeling and Control for Islanding Operation of Active Distribution Systems

DEFF Research Database (Denmark)

Cha, Seung-Tae; Wu, Qiuwei; Saleem, Arshad

2011-01-01

to stabilize the frequency. Different agents are defined to represent different resources in the distribution systems. A test platform with a real time digital simulator (RTDS), an OPen Connectivity (OPC) protocol server and the multi-agent based intelligent controller is established to test the proposed multi......Along with the increasing penetration of distributed generation (DG) in distribution systems, there are more resources for system operators to improve the operation and control of the whole system and enhance the reliability of electricity supply to customers. The distribution systems with DG...... are able to operate in is-landing operation mode intentionally or unintentionally. In order to smooth the transition from grid connected operation to islanding operation for distribution systems with DG, a multi-agent based controller is proposed to utilize different re-sources in the distribution systems...

Bolted Flanged Connection for Critical Plant/Piping Systems

International Nuclear Information System (INIS)

Efremov, Anatoly

2006-01-01

A novel type of Bolted Flanged Connection with bolts and gasket manufactured on a basis of advanced Shape Memory Alloys is examined. Presented approach combined with inverse flexion flange design of plant/piping joint reveals a significant increase of internal pressure under conditions of a variety of operating temperatures relating to critical plant/piping systems. (author)

Expected Improvements in Work Truck Efficiency Through Connectivity and Automation

Energy Technology Data Exchange (ETDEWEB)

Walkowicz, Kevin A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-12

This presentation focuses on the potential impact of connected and automated technologies on commercial vehicle operations. It includes topics such as the U.S. Department of Energy's Energy Efficient Mobility Systems (EEMS) program and the Systems and Modeling for Accelerated Research in Transportation (SMART) Mobility Initiative. It also describes National Renewable Energy Laboratory (NREL) research findings pertaining to the potential energy impacts of connectivity and automation and stresses the need for integration and optimization to take advantage of the benefits offered by these transformative technologies while mitigating the potential negative consequences.

Decentralized electricity generation by using photovoltaic grid-connected solar system

International Nuclear Information System (INIS)

Tyutyundziev, N.; Vitanov, P.; Radkov, R.; Grottke, M.

2006-01-01

AcadPV is the first demonstration installation connected permanently to LV grid in Sofia, Bulgaria aiming at assessment of PV efficiencies and cost-effectiveness. A thorough analysis has been carried out in order to select PV system site, supporting construction design and orientation. The PV generator is divided to 3 PV subfields equipped by 3 SUNPOWER inverters connected to 3 separated phases of the grid. The performance of 10kWp PV system has been evaluated during the first year of operation and compared to PV simulation software results

Rotation of a piston pin in the small connecting rod eye during engine operation; Drehung eines Kolbenbolzens im kleinen Pleuelauge waehrend des Motorbetriebs

Energy Technology Data Exchange (ETDEWEB)

Wachtmeister, Georg; Hubert, Andreas [Technische Univ. Muenchen (DE). Lehrstuhl fuer Verbrennungskraftmaschinen (LVK)

2008-12-15

A constant increase of powerful combustion engines has lead to higher loads on the crankshaft drive and piston pin. To ensure a robust design the effective forces and movements at the piston pin have to be known. At the Technische Universitaet Muenchen, Chair of Internal Combustion Engines, a research project looked into the piston pins movement during engine operation. The main goal was to determine the rotary movements of the piston pin by measurement at a 4-l gas SI engine as a function of the engine load and speed and to clarify the mechanisms that cause the rotary movement of the piston pin especially in the small connecting rod eye. (orig.)

On the holonomy of the Coulomb connection over manifolds with boundary

International Nuclear Information System (INIS)

Gryc, William E.

2008-01-01

Narasimhan and Ramadas [Commun. Math. Phys. 67, 121 (1979)] showed that the restricted holonomy group of the Coulomb connection is dense in the connected component of the identity of the gauge group when one considers the product principal bundle S 3 xSU(2)→S 3 . Instead of a base manifold S 3 , we consider here a base manifold of dimension n≥2 with a boundary and use Dirichlet boundary conditions on connections as defined by Marini [Commun. Pure Appl. Math. 45, 1015 (1992)]. A key step in the method of Narasimhan and Ramadas consisted in showing that the linear space spanned by the curvature form at one specially chosen connection is dense in the holonomy Lie algebra with respect to an appropriate Sobolev norm. Our objective is to explore the effect of the presence of a boundary on this construction of the holonomy Lie algebra. Fixing appropriate Sobolev norms, it will be shown that the space spanned, linearly, by the curvature form at any one connection is never dense in the holonomy Lie algebra. In contrast, the linear space spanned by the curvature form and its first commutators at the flat connection is dense and, in the C ∞ category, is in fact the entire holonomy Lie algebra. The former, negative, theorem is proven for a general principle bundle over M, while the latter, positive, theorem is proven only for a product bundle over the closure of a bounded open subset of R n . Our technique for proving the absence of density consists in showing that the linear space spanned by the curvature form at one point is contained in the kernel of a linear map consisting of a third order differential operator, followed by a restriction operation at the boundary; this mapping is determined by the mean curvature of the boundary

Establishment of key grid-connected performance index system for integrated PV-ES system

Science.gov (United States)

Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

2016-08-01

In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

Finite Blaschke products and their connections

CERN Document Server

Garcia, Stephan Ramon; Ross, William T

2018-01-01

This monograph offers an introduction to finite Blaschke products and their connections to complex analysis, linear algebra, operator theory, matrix analysis, and other fields. Old favorites such as the Carathéodory approximation and the Pick interpolation theorems are featured, as are many topics that have never received a modern treatment, such as the Bohr radius and Ritt's theorem on decomposability. Deep connections to hyperbolic geometry are explored, as are the mapping properties, zeros, residues, and critical points of finite Blaschke products. In addition, model spaces, rational functions with real boundary values, spectral mapping properties of the numerical range, and the Darlington synthesis problem from electrical engineering are also covered. Topics are carefully discussed, and numerous examples and illustrations highlight crucial ideas. While thorough explanations allow the reader to appreciate the beauty of the subject, relevant exercises following each chapter improve technical fluency with t...

Principles of psychological confidence of NPP operators

International Nuclear Information System (INIS)

Alpeev, A.S.

1994-01-01

The problems of operator interaction with subsystems supporting his activity are discussed from the point of view of formation of his psychological confidence on the basis of the automation intellectual means capabilities. The functions of operator activity supporting subsystems, which realization will provide to decrease greatly the portion of accidents at NPPs connected with mistakes in operator actions, are derived. 6 refs

Electric circuit breaker comprising a plurality of vacuum interrupters simultaneously operated by a common operator

Science.gov (United States)

Barkan, Philip; Imam, Imdad

1980-01-01

This circuit breaker comprises a plurality of a vacuum-type circuit interrupters, each having a movable contact rod. A common operating device for the interrupters comprises a linearly-movable operating member. The interrupters are mounted at one side of the operating member with their movable contact rods extending in a direction generally toward the operating member. Means is provided for mechanically coupling the operating member to the contact rods, and this means comprises a plurality of insulating operating rods, each connected at one end to the operating member and at its opposite end to one of the movable contact rods. The operating rods are of substantially equal length and have longitudinal axes that converge and intersect at substantially a common point.

The challenges of connecting generation to distribution systems: a utility perspective

International Nuclear Information System (INIS)

Kropp, F.

2004-01-01

'Full text:' This presentation discusses the technical, financial and regulatory barriers to connecting generation to Distribution Systems in Ontario. Case studies will be used to provide examples of the operational and technical challenges that impact the utility as well as a discussion on the site-specific advantages and disadvantages (to the utility) of the generation connections. These studies will include discussions on the problems and lessons learned with respect to the overall project implementation and the contractual agreements. The case studies will be complemented by an explanation of the financial constraints (both short term and long term) associated with the connections, and the regulatory issues that impact the financial recovery models including net and gross load billing. (author)

Modelling and Simulation of VSC-HVDC Connection for Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro

2009-01-01

This paper describes the modelling and simulation of offshore wind power plants (WPP) connected to the onshore power system grid by VSC based HVDC transmission. Offshore wind power plant is modelled with several wind turbine generators connected to two separate collector buses with their own plant...... wind turbines. Simulation of power ramping up and down as well as steady state operation has been demonstrated. As an additional case, the primary reserve control logic has been implemented and simulated in PSCAD model....

Quantized fields and operators on a partial inner product space

International Nuclear Information System (INIS)

Shabani, J.

1985-11-01

We investigate the connection between the space OpV of all operators on a partial inner product space V and the weak sequential completion of the * algebra L + (Vsup(no.)) of all operators X such that Vsup(no.) is contained in D(X) intersection D(X*) and both X and its adjoint X* leave Vsup(no.) invariant. This connection gives a mathematical description of quantized fields in terms of elements of OpV. (author)

Delta Power Control Strategy for Multistring Grid-Connected PV Inverters

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

, is required for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control (DPC) for grid-connected PV systems is presented, where the multistring PV inverter configuration is adopted. This control strategy is a combination of maximum power point...... tracking (MPPT) and constant power generation (CPG) modes. In this control scheme, one PV string operating in the MPPT mode estimates the available power, whereas the other PV strings regulate the total PV power by the CPG control strategy in such a way that the delta power constraint for the entire PV...... system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the proposed DPC strategy, where the power reserve according to the delta power constraint is achieved under several operating conditions....

Distributed Operations Planning

Science.gov (United States)

Fox, Jason; Norris, Jeffrey; Powell, Mark; Rabe, Kenneth; Shams, Khawaja

2007-01-01

Maestro software provides a secure and distributed mission planning system for long-term missions in general, and the Mars Exploration Rover Mission (MER) specifically. Maestro, the successor to the Science Activity Planner, has a heavy emphasis on portability and distributed operations, and requires no data replication or expensive hardware, instead relying on a set of services functioning on JPL institutional servers. Maestro works on most current computers with network connections, including laptops. When browsing down-link data from a spacecraft, Maestro functions similarly to being on a Web browser. After authenticating the user, it connects to a database server to query an index of data products. It then contacts a Web server to download and display the actual data products. The software also includes collaboration support based upon a highly reliable messaging system. Modifications made to targets in one instance are quickly and securely transmitted to other instances of Maestro. The back end that has been developed for Maestro could benefit many future missions by reducing the cost of centralized operations system architecture.

Use of agents to optimize traffic over wireless mobile connections

Science.gov (United States)

Helin, Mikko; Jarvinen, Jari; Kalliokorpi, Janne; Kolehmainen, Jari; Narikka, Jorma

2002-08-01

Wireless mobile connections have some well known disadvantages, like slow data rate, high and variable error-rate. In addition to that there are possible (and probable) inefficiencies when connecting different types of protocols stacks, like running TCP over GPRS. On the other hand mobile and portable devices have some limitations, which are based on their size and cannot therefore be removed totally. Potential users are so-called common people and they would like to have very simple-to-use applications solving their daily problems, not causing new ones. One approach to make this situation better is to use agents. They could operate on many different levels, like connecting different physical servers to produce the service needed, connecting different services together, optimizing for different types of user devices, connecting different message types (like audio, animation etc.) to produce the service, making transformations (like reading e-mails as voice mail etc.). This paper will discuss these various aspects of agent technology in the context of mobile services provided to consumers. Discussion and conclusions are partly based on the ZanderMail project. Although it is a mail agent project its results can easily be extended to various message types and various other services, like those based on the location of mobile device. The paper will cover widely these different ideas and ZanderMail is just used as an example and a tool for testing various issues. The idea is to utilize agents many ways to fade away at least partly those known problems mentioned in the beginning. An agent could operate in the network quite near the mobile device to overcome the problem caused by different protocol stacks. It could make logical decisions based on location and other local information, like weather, and it could handle priority issues on various levels of application(s).

Sales and operations planning

DEFF Research Database (Denmark)

Kjellsdotter, Linea; Dukovska-Popovska, Iskra; Kaipia, Riikka

2013-01-01

This paper explores how the use of sales and operations planning (S&OP) may deal with the challenges set by the planning environment by investigating S&OP at four Scandinavian industrial food producers. Variables connected to the product and market, e.g. perishability, customer service elements...

Harmonic emission limits and responsibilities at a point of connection

NARCIS (Netherlands)

Bhattacharyya, S.; Cobben, J.F.G.; Ribeiro, P.F.; Kling, W.L.

2012-01-01

A customer expects to receive a voltage supply at his installation that meets the requirements of standards like (national) grid codes, EN50160 standard etc. under normal operating conditions. On the other hand, the devices connected to a customer's installation should meet power quality (PQ)

Electromagnetically Operated Counter

Science.gov (United States)

Goldberg, H D; Goldberg, M I

1951-12-18

An electromagnetically operated counter wherein signals to be counted are applied to cause stepwise rotation of a rotatable element which is connected to a suitable register. The mechanism involved consists of a rotatable armature having three spaced cores of magnetic material and a pair of diametrically opposed electromagnets with a suitable pulsing circuit to actuate the magnets.

Operation of grid-connected DFIG under unbalanced grid voltage condition

NARCIS (Netherlands)

Zhou, Y.; Bauer, P.; Ferreira, J.A.; Pierik, J.

2009-01-01

Doubly fed induction generator (DFIG) still shares a large part in today's wind power market. It provides the benefits of variable speed operation cost-effectively, and can control its active and reactive power independently. Crowbar protection is often adopted to protect the rotor-side voltage

Methods for the secure and economical operation of inter-connected electrical power systems

Energy Technology Data Exchange (ETDEWEB)

Iggland, L. J. E.

2014-07-01

This thesis considers aspects of the operation of electric power systems. In particular the focus is on the operation in systems where multiple operators are jointly responsible for the operation of an interconnected system, but where each operator is solely responsible for a sub-system. Due to the manner in which the operation is separated, the operators have detailed information about the subsystem they control, but only limited information about the rest of the system. The market liberalization, and an interest in an integrated pan-European energy market, are leading to increased cross-border power flows. These increased cross-border flows increase the interdependencies between the areas. With increasing interdependencies the problems associated with operators only having limited knowledge about the entire system increase. In order to reduce these issues, which include an inability to properly dispatch generation and being able to perform security analysis, this thesis presents methods which can be used to perform data-exchange without requiring that all information needs to be exchanged. By using repeated exchange of the price and amount of energy traded together with an iterative solution of the local generation dispatch problem, a multi-lateral solution for the interconnected system is achieved. The method is evaluated with respect to how close its solution is to the central one, both for the non-security constrained and the security constrained case. This method is then extended to include HVDC transmission systems. In order to allow the operators to evaluate the effect of contingencies which occur in other areas, the operators must exchange the contingencies which they consider with each other. In order to reduce the amount of data which must be transmitted this thesis proposes a method which summarizes contingencies which are similar into a common one. Thus allowing for a smaller number of contingencies to be considered, without reducing the coverage. This

Methods for the secure and economical operation of inter-connected electrical power systems

International Nuclear Information System (INIS)

Iggland, L. J. E.

2014-01-01

This thesis considers aspects of the operation of electric power systems. In particular the focus is on the operation in systems where multiple operators are jointly responsible for the operation of an interconnected system, but where each operator is solely responsible for a sub-system. Due to the manner in which the operation is separated, the operators have detailed information about the subsystem they control, but only limited information about the rest of the system. The market liberalization, and an interest in an integrated pan-European energy market, are leading to increased cross-border power flows. These increased cross-border flows increase the interdependencies between the areas. With increasing interdependencies the problems associated with operators only having limited knowledge about the entire system increase. In order to reduce these issues, which include an inability to properly dispatch generation and being able to perform security analysis, this thesis presents methods which can be used to perform data-exchange without requiring that all information needs to be exchanged. By using repeated exchange of the price and amount of energy traded together with an iterative solution of the local generation dispatch problem, a multi-lateral solution for the interconnected system is achieved. The method is evaluated with respect to how close its solution is to the central one, both for the non-security constrained and the security constrained case. This method is then extended to include HVDC transmission systems. In order to allow the operators to evaluate the effect of contingencies which occur in other areas, the operators must exchange the contingencies which they consider with each other. In order to reduce the amount of data which must be transmitted this thesis proposes a method which summarizes contingencies which are similar into a common one. Thus allowing for a smaller number of contingencies to be considered, without reducing the coverage. This

Phase Balancing by Means of Electric Vehicles Single-Phase Connection Shifting in a Low Voltage Danish Grid

DEFF Research Database (Denmark)

Lico, Pasqualino; Marinelli, Mattia; Knezovic, Katarina

2015-01-01

In Denmark, household consumers are supplied with three phase with neutral cable. In addition, the distribution service operator cannot decide to which phase electrical appliance are connected. The technician who realizes the installation connects the loads according to his technical expertise...

The smart/connected city and its implications for connected transportation.

Science.gov (United States)

2014-10-14

This white paper outlines the potential for the emerging connected transportation system to interface with smart/connected cities. Its aim is to lay the foundation for defining steps that the U.S. Department of Transportation (USDOT) Connected Vehicl...

Connection Management and Recovery Strategies under Epidemic Network Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2014-01-01

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under attacks. This work proposes four policies for failure handling in a connection-oriented optical transport network, under Generalized MultiProtocol Label Switching control plane, and evaluates their performance under multiple correlated large-scale failures. We employ the Susceptible...... of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections requiring recovery, which translates in improved quality of service to customers....

CMIS arithmetic and multiwire news for QCD on the connection machine

International Nuclear Information System (INIS)

Brickner, R.G.

1991-01-01

Our collaboration has been running Wilson fermion QCD simulations on various Connection Machines for over a year and a half. During this time, we have continually optimized our code for operations found in the fermion matrix inversion. Our current version of the matrix inversion is written almost entirely in CMIS (Connection Machine Instruction Set), and utilizes both high-speed arithmetic and multiwire 'news' (nearest-neighbor communications). We present details of how these and other features of our code are implemented on the CM-2. (orig.)

Monolithic blue LED series arrays for high-voltage AC operation

Energy Technology Data Exchange (ETDEWEB)

Ao, Jin-Ping [Satellite Venture Business Laboratory, University of Tokushima, Tokushima 770-8506 (Japan); Sato, Hisao; Mizobuchi, Takashi; Morioka, Kenji; Kawano, Shunsuke; Muramoto, Yoshihiko; Sato, Daisuke; Sakai, Shiro [Nitride Semiconductor Co. Ltd., Naruto, Tokushima 771-0360 (Japan); Lee, Young-Bae; Ohno, Yasuo [Department of Electrical and Electronic Engineering, University of Tokushima, Tokushima 770-8506 (Japan)

2002-12-16

Design and fabrication of monolithic blue LED series arrays that can be operated under high ac voltage are described. Several LEDs, such as 3, 7, and 20, are connected in series and in parallel to meet ac operation. The chip size of a single device is 150 {mu}m x 120 {mu}m and the total size is 1.1 mm x 1 mm for a 40(20+20) LED array. Deep dry etching was performed as device isolation. Two-layer interconnection and air bridge are utilized to connect the devices in an array. The monolithic series array exhibit the expected operation function under dc and ac bias. The output power and forward voltage are almost proportional to LED numbers connected in series. On-wafer measurement shows that the output power is 40 mW for 40(20+20) LED array under ac 72 V. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology.

Science.gov (United States)

Pakdel, Majid; Jalilzadeh, Saeid

2017-09-29

In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

Mapping a Careflow Network to assess the connectedness of Connected Health.

Science.gov (United States)

Carroll, Noel; Richardson, Ita

2017-04-01

Connected Health is an emerging and rapidly developing field which has the potential to transform healthcare service systems by increasing its safety, quality and overall efficiency. From a healthcare perspective, process improvement models have mainly focused on the static workflow viewpoint. The objective of this article is to study and model the dynamic nature of healthcare delivery, allowing us to identify where potential issues exist within the service system and to examine how Connected Health technological solutions may support service efficiencies. We explore the application of social network analysis (SNA) as a modelling technique which captures the dynamic nature of a healthcare service. We demonstrate how it can be used to map the 'Careflow Network' and guide Connected Health innovators to examine specific opportunities within the healthcare service. Our results indicate that healthcare technology must be correctly identified and implemented within the Careflow Network to enjoy improvements in service delivery. Oftentimes, prior to making the transformation to Connected Health, researchers use various modelling techniques that fail to identify where Connected Health innovation is best placed in a healthcare service network. Using SNA allows us to develop an understanding of the current operation of healthcare system within which they can effect change. It is important to identify and model the resource exchanges to ensure that the quality and safety of care are enhanced, efficiencies are increased and the overall healthcare service system is improved. We have shown that dynamic models allow us to study the exchange of resources. These are often intertwined within a socio-technical context in an informal manner and not accounted for in static models, yet capture a truer insight on the operations of a Careflow Network.

A New Power Calculation Method for Single-Phase Grid-Connected Systems

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede

2013-01-01

A new method to calculate average active power and reactive power for single-phase systems is proposed in this paper. It can be used in different applications where the output active power and reactive power need to be calculated accurately and fast. For example, a grid-connected photovoltaic...... system in low voltage ride through operation mode requires a power feedback for the power control loop. Commonly, a Discrete Fourier Transform (DFT) based power calculation method can be adopted in such systems. However, the DFT method introduces at least a one-cycle time delay. The new power calculation...... method, which is based on the adaptive filtering technique, can achieve a faster response. The performance of the proposed method is verified by experiments and demonstrated in a 1 kW single-phase grid-connected system operating under different conditions.Experimental results show the effectiveness...

Construction of Nijenhuis operators and dendriform trialgebras

Directory of Open Access Journals (Sweden)

Philippe Leroux

2004-01-01

Full Text Available We construct Nijenhuis operators from particular bialgebras called dendriform-Nijenhuis bialgebras. It turns out that such Nijenhuis operators commute with TD-operators, a kind of Baxter-Rota operators, and are therefore closely related to dendriform trialgebras. This allows the construction of associative algebras, called dendriform-Nijenhuis algebras, made out of nine operations and presenting an exotic combinatorial property. We also show that the augmented free dendriform-Nijenhuis algebra and its commutative version have a structure of connected Hopf algebras. Examples are given.

Using military friendships to optimize postdeployment reintegration for male Operation Iraqi Freedom/Operation Enduring Freedom veterans.

Science.gov (United States)

Hinojosa, Ramon; Hinojosa, Melanie Sberna

2011-01-01

Social relationships are important to health out comes. The postdeployment family reintegration literature focuses on the role of the civilian family in facilitating the transition from Active Duty military deployment to civilian society. The focus on the civilian family relationship may miss other important personal connections in veterans' lives. One such connection is the relationship many veterans have with former military unit members who served with them when deployed. Drawing on interviews with male Operation Iraqi Freedom/Operation Enduring Freedom veterans conducted from 2008 to 2009, we argue that the members of a military unit, especially during armed conflict, should be considered a resource to help the "family" reintegration process rather than impede it. This research has implications for current reintegration policy and how best to assist veterans transitioning into civilian society.

Functional equations with causal operators

CERN Document Server

Corduneanu, C

2003-01-01

Functional equations encompass most of the equations used in applied science and engineering: ordinary differential equations, integral equations of the Volterra type, equations with delayed argument, and integro-differential equations of the Volterra type. The basic theory of functional equations includes functional differential equations with causal operators. Functional Equations with Causal Operators explains the connection between equations with causal operators and the classical types of functional equations encountered by mathematicians and engineers. It details the fundamentals of linear equations and stability theory and provides several applications and examples.

INTEGRATED SENSOR EVALUATION CIRCUIT AND METHOD FOR OPERATING SAID CIRCUIT

OpenAIRE

Krüger, Jens; Gausa, Dominik

2015-01-01

WO15090426A1 Sensor evaluation device and method for operating said device Integrated sensor evaluation circuit for evaluating a sensor signal (14) received from a sensor (12), having a first connection (28a) for connection to the sensor and a second connection (28b) for connection to the sensor. The integrated sensor evaluation circuit comprises a configuration data memory (16) for storing configuration data which describe signal properties of a plurality of sensor control signals (26a-c). T...

Manifolds with integrable affine shape operator

Directory of Open Access Journals (Sweden)

Daniel A. Joaquín

2005-05-01

Full Text Available This work establishes the conditions for the existence of vector fields with the property that theirs covariant derivative, with respect to the affine normal connection, be the affine shape operatorS in hypersurfaces. Some results are obtained from this property and, in particular, for some kind of affine decomposable hypersurfaces we explicitely get the actual vector fields.

The Challenge of Wireless Connectivity to Support Intelligent Mines

DEFF Research Database (Denmark)

Barbosa, Viviane S. B.; Garcia, Luis G. U.; Caldwell, George

2016-01-01

The need for continuous safety improvements and increased operational efficiency is driving the mining industry through a transition towards large-scale automation of operations, i.e., “intelligent mines”. The technology promises to remove human operators from harsh or dangerous conditions...... for unmanned mine operations. Although voice and narrowband data radios have been used for years to support several types of mining activities, such as fleet management (dispatch) and telemetry, the use of automated equipment introduces a new set of connectivity requirements and poses a set of challenges...... in terms of network planning, management and optimization. For example, the data rates required to support unmanned equipment, e.g. a teleoperated bulldozer, shift from a few kilobits/second to megabits/second due to live video feeds. This traffic volume is well beyond the capabilities of Professional...

DFIG-based offshore wind power plant connected to a single VSC-HVDC operated at variable frequency: Energy yield assessment

International Nuclear Information System (INIS)

De-Prada-Gil, Mikel; Díaz-González, Francisco; Gomis-Bellmunt, Oriol; Sumper, Andreas

2015-01-01

The existence of HVDC (High Voltage Direct Current) transmission systems for remote offshore wind power plants allows devising novel wind plant concepts, which do not need to be synchronized with the main AC grid. This paper proposes an OWPP (offshore wind power plant) design based on variable speed wind turbines driven by DFIGs (doubly fed induction generators) with reduced power electronic converters connected to a single VSC-HVDC converter which operates at variable frequency and voltage within the collection grid. It is aimed to evaluate the influence of the power converter size and wind speed variability within the WPP on energy yield efficiency, as well as to develop a coordinated control between the VSC-HVDC converter and the individual back-to-back reduced power converters of each DFIG-based wind turbine in order to provide control capability for the wind power plant at a reduced cost. To maximise wind power generation by the OWPP, an optimum electrical frequency search algorithm for the VSC-HVDC converter is proposed. Both central wind power plant control level and local wind turbine control level are presented and the performance of the system is validated by means of simulations using MATLAB/Simulink ® . - Highlights: • Influence of converter size and wind speed variability on energy capture efficiency. • Coordinated control between a VSC-HVDC and DFIG WTs with reduced power converters. • Static and dynamic analysis of the performance of the implemented control scheme. • Optimal variable frequency operation to maximize WPP generation at a reduced cost

Network connectivity value.

Science.gov (United States)

Dragicevic, Arnaud; Boulanger, Vincent; Bruciamacchie, Max; Chauchard, Sandrine; Dupouey, Jean-Luc; Stenger, Anne

2017-04-21

In order to unveil the value of network connectivity, we formalize the construction of ecological networks in forest environments as an optimal control dynamic graph-theoretic problem. The network is based on a set of bioreserves and patches linked by ecological corridors. The node dynamics, built upon the consensus protocol, form a time evolutive Mahalanobis distance weighted by the opportunity costs of timber production. We consider a case of complete graph, where the ecological network is fully connected, and a case of incomplete graph, where the ecological network is partially connected. The results show that the network equilibrium depends on the size of the reception zone, while the network connectivity depends on the environmental compatibility between the ecological areas. Through shadow prices, we find that securing connectivity in partially connected networks is more expensive than in fully connected networks, but should be undertaken when the opportunity costs are significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

Connectivity Neurofeedback Training Can Differentially Change Functional Connectivity and Cognitive Performance.

Science.gov (United States)

Yamashita, Ayumu; Hayasaka, Shunsuke; Kawato, Mitsuo; Imamizu, Hiroshi

2017-10-01

Advances in functional magnetic resonance imaging have made it possible to provide real-time feedback on brain activity. Neurofeedback has been applied to therapeutic interventions for psychiatric disorders. Since many studies have shown that most psychiatric disorders exhibit abnormal brain networks, a novel experimental paradigm named connectivity neurofeedback, which can directly modulate a brain network, has emerged as a promising approach to treat psychiatric disorders. Here, we investigated the hypothesis that connectivity neurofeedback can induce the aimed direction of change in functional connectivity, and the differential change in cognitive performance according to the direction of change in connectivity. We selected the connectivity between the left primary motor cortex and the left lateral parietal cortex as the target. Subjects were divided into 2 groups, in which only the direction of change (an increase or a decrease in correlation) in the experimentally manipulated connectivity differed between the groups. As a result, subjects successfully induced the expected connectivity changes in either of the 2 directions. Furthermore, cognitive performance significantly and differentially changed from preneurofeedback to postneurofeedback training between the 2 groups. These findings indicate that connectivity neurofeedback can induce the aimed direction of change in connectivity and also a differential change in cognitive performance. © The Author 2017. Published by Oxford University Press.

Analysis of series resonant converter with series-parallel connection

Science.gov (United States)

Lin, Bor-Ren; Huang, Chien-Lan

2011-02-01

In this study, a parallel inductor-inductor-capacitor (LLC) resonant converter series-connected on the primary side and parallel-connected on the secondary side is presented for server power supply systems. Based on series resonant behaviour, the power metal-oxide-semiconductor field-effect transistors are turned on at zero voltage switching and the rectifier diodes are turned off at zero current switching. Thus, the switching losses on the power semiconductors are reduced. In the proposed converter, the primary windings of the two LLC converters are connected in series. Thus, the two converters have the same primary currents to ensure that they can supply the balance load current. On the output side, two LLC converters are connected in parallel to share the load current and to reduce the current stress on the secondary windings and the rectifier diodes. In this article, the principle of operation, steady-state analysis and design considerations of the proposed converter are provided and discussed. Experiments with a laboratory prototype with a 24 V/21 A output for server power supply were performed to verify the effectiveness of the proposed converter.

Assembly for connecting the column ends of two capillary columns

International Nuclear Information System (INIS)

Kolb, B.; Auer, M.; Pospisil, P.

1984-01-01

In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

Wind power integration connection and system operational aspects

CERN Document Server

Fox, Brendan

2014-01-01

Wind Power Integration provides a wide-ranging discussion on all major aspects of wind power integration into electricity supply systems. This second edition has been fully revised and updated to take account of the significant growth in wind power deployment in the past few years. New discussions have been added to describe developments in wind turbine generator technology and control, the network integration of wind power, innovative ways to integrate wind power when its generation potential exceeds 50% of demand, case studies on how forecasting errors have affected system operation, and an update on how the wind energy sector has fared in the marketplace. Topics covered include: the development of wind power technology and its world-wide deployment; wind power technology and the interaction of various wind turbine generator types with the utility network; and wind power forecasting and the challenges faced by wind energy in modern electricity markets.

Control voltage and power fluctuations when connecting wind farms

Science.gov (United States)

Berinde, Ioan; Bǎlan, Horia; Oros Pop, Teodora Susana

2015-12-01

Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

Control voltage and power fluctuations when connecting wind farms

International Nuclear Information System (INIS)

Berinde, Ioan; Bălan, Horia; Oros, Teodora Susana

2015-01-01

Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve

Control voltage and power fluctuations when connecting wind farms

Energy Technology Data Exchange (ETDEWEB)

Berinde, Ioan, E-mail: ioan-berinde@yahoo.com; Bălan, Horia, E-mail: hbalan@mail.utcluj.ro; Oros, Teodora Susana, E-mail: teodoraoros-87@yahoo.com [Technical University of Cluj-Napoca, Romania, Faculty of Electrical Engineering, Department of Power Engineering and Management (Romania)

2015-12-23

Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

Sales and operations planning

DEFF Research Database (Denmark)

Kjellsdotter, Linea; Dukovska-Popovska, Iskra; Kaipia, Riikka

2015-01-01

This paper investigates sales and operations planning (S&OP) at four Scandinavian industrial food producers in order to explore how the use of S&OP might help leaders to deal with the challenges set by the planning environment. Variables connected to the product and market, e.g., frequency of new...

Performance evaluation of 10 MW grid connected solar photovoltaic power plant in India

Directory of Open Access Journals (Sweden)

B. Shiva Kumar

2015-11-01

Full Text Available The growing energy demand in developing nations has triggered the issue of energy security. This has made essential to utilize the untapped potential of renewable resources. Grid connected PV systems have become the best alternatives in renewable energy at large scale. Performance analysis of these grid connected plants could help in designing, operating and maintenance of new grid connected systems. A 10 MW photovoltaic grid connected power plant commissioned at Ramagundam is one of the largest solar power plants with the site receiving a good average solar radiation of 4.97 kW h/m2/day and annual average temperature of about 27.3 degrees centigrade. The plant is designed to operate with a seasonal tilt. In this study the solar PV plant design aspects along with its annual performance is elaborated. The various types of power losses (temperature, internal network, power electronics, grid connected etc. and performance ratio are also calculated. The performance results of the plant are also compared with the simulation values obtained from PV syst and PV-GIS software. The final yield (Y F of plant ranged from 1.96 to 5.07 h/d, and annual performance ratio (PR of 86.12%. It has 17.68% CUF with annual energy generation of 15798.192 MW h/Annum.

String operator formalism and functional intergal in the holomorphic representation

International Nuclear Information System (INIS)

Losev, A.S.; Morozov, A.Yu.; Rislyj, A.A.; Shatashvili, S.L.

1989-01-01

Connection between the continual integral over open Riemann surfaces and the operator formalism on closed Riemann surfaces is discussed. States of the operator formalism are the holomorphic representation of the continual integral

Minimum cost connection networks

DEFF Research Database (Denmark)

Hougaard, Jens Leth; Tvede, Mich

In the present paper we consider the allocation of cost in connection networks. Agents have connection demands in form of pairs of locations they want to be connected. Connections between locations are costly to build. The problem is to allocate costs of networks satisfying all connection demands...

DISSECTING HABITAT CONNECTIVITY

Science.gov (United States)

abstractConnectivity is increasingly recognized as an important element of a successful reserve design. Connectivity matters in reserve design to the extent that it promotes or hinders the viability of target populations. While conceptually straightforward, connectivity i...

How to ensure reliable connectivity for aerial vehicles over cellular networks

DEFF Research Database (Denmark)

Nguyen, Huan Cong; Amorim, Rafhael Medeiros de; Wigard, Jeroen

2018-01-01

reliable operation of aerial vehicles in various deployment scenarios. In this paper, we investigate the performance of aerial radio connectivity in a typical rural area network deployment using extensive channel measurements and system simulations. First, we highlight that downlink and uplink radio...

Establishing Connectivity

DEFF Research Database (Denmark)

Kjær, Poul F.

Global law settings are characterised by a structural pre-eminence of connectivity norms, a type of norm which differs from coherency or possibility norms. The centrality of connectivity norms emerges from the function of global law, which is to increase the probability of transfers of condensed ...... and human rights can be understood as serving a constitutionalising function aimed at stabilising and facilitating connectivity. This allows for an understanding of colonialism and contemporary global governance as functional, but not as normative, equivalents.......Global law settings are characterised by a structural pre-eminence of connectivity norms, a type of norm which differs from coherency or possibility norms. The centrality of connectivity norms emerges from the function of global law, which is to increase the probability of transfers of condensed...... social components, such as economic capital and products, religious doctrines and scientific knowledge, from one legally structured context to another within world society. This was the case from colonialism and colonial law to contemporary global supply chains and human rights. Both colonial law...

The Text of the Agreement of 22 July 1977 between Argentina and the Agency for the Application of Safeguards in Connection with a Co-operation Agreement between Argentina and Canada

Energy Technology Data Exchange (ETDEWEB)

NONE

1977-11-28

The text of the Agreement of 22 July 1977 between Argentina and the Agency for the application of safeguards in connection with the Agreement of 30 January 1976 between the Governments of Argentina and Canada for co-operation in the development and application of atomic energy for peaceful purposes is reproduced in this document for the information of all Members. The Agreement entered into force, pursuant to Section 31, on 22 July 1977.

The Text of the Agreement of 22 July 1977 between Argentina and the Agency for the Application of Safeguards in Connection with a Co-operation Agreement between Argentina and Canada

International Nuclear Information System (INIS)

1977-01-01

The text of the Agreement of 22 July 1977 between Argentina and the Agency for the application of safeguards in connection with the Agreement of 30 January 1976 between the Governments of Argentina and Canada for co-operation in the development and application of atomic energy for peaceful purposes is reproduced in this document for the information of all Members. The Agreement entered into force, pursuant to Section 31, on 22 July 1977.

Grid-Forming-Mode Operation of Boost-Power-Stage Converter in PV-Generator-Interfacing Applications

Directory of Open Access Journals (Sweden)

Jukka Viinamäki

2017-07-01

Full Text Available The application of constant power control and inclusion of energy storage in grid-connected photovoltaic (PV energy systems may increase the use of two-stage system structures composed of DC–DC-converter-interfaced PV generator and grid-connected inverter connected in cascade. A typical PV-generator-interfacing DC–DC converter is a boost-power-stage converter. The renewable energy system may operate in three different operation modes—grid-forming, grid-feeding, and grid-supporting modes. In the last two operation modes, the outmost feedback loops are taken from the input terminal of the associated power electronic converters, which usually does not pose stability problems in terms of their input sources. In the grid-forming operation mode, the outmost feedback loops have to be connected to the output terminal of the associated power electronic converters, and hence the input terminal will behave as a negative incremental resistor at low frequencies. This property will limit the operation of the PV interfacing converter in either the constant voltage or constant current region of the PV generator for ensuring stable operation. The boost-power-stage converter can be applied as a voltage or current-fed converter limiting the stable operation region accordingly. The investigations of this paper show explicitly that only the voltage-fed mode would provide feasible dynamic and stability properties as a viable interfacing converter.

Connecting to the Internet Securely; Protecting Home Networks CIAC-2324

Energy Technology Data Exchange (ETDEWEB)

Orvis, W J; Krystosek, P; Smith, J

2002-11-27

With more and more people working at home and connecting to company networks via the Internet, the risk to company networks to intrusion and theft of sensitive information is growing. Working from home has many positive advantages for both the home worker and the company they work for. However, as companies encourage people to work from home, they need to start considering the interaction of the employee's home network and the company network he connects to. This paper discusses problems and solutions related to protection of home computers from attacks on those computers via the network connection. It does not consider protection of those systems from people who have physical access to the computers nor does it consider company laptops taken on-the-road. Home networks are often targeted by intruders because they are plentiful and they are usually not well secured. While companies have departments of professionals to maintain and secure their networks, home networks are maintained by the employee who may be less knowledgeable about network security matters. The biggest problems with home networks are that: Home networks are not designed to be secure and may use technologies (wireless) that are not secure; The operating systems are not secured when they are installed; The operating systems and applications are not maintained (for security considerations) after they are installed; and The networks are often used for other activities that put them at risk for being compromised. Home networks that are going to be connected to company networks need to be cooperatively secured by the employee and the company so they do not open up the company network to intruders. Securing home networks involves many of the same operations as securing a company network: Patch and maintain systems; Securely configure systems; Eliminate unneeded services; Protect remote logins; Use good passwords; Use current antivirus software; and Moderate your Internet usage habits. Most of these

Minimum cost connection networks

DEFF Research Database (Denmark)

Hougaard, Jens Leth; Tvede, Mich

2015-01-01

In the present paper we consider the allocation of costs in connection networks. Agents have connection demands in form of pairs of locations they want to have connected. Connections between locations are costly to build. The problem is to allocate costs of networks satisfying all connection...... demands. We use a few axioms to characterize allocation rules that truthfully implement cost minimizing networks satisfying all connection demands in a game where: (1) a central planner announces an allocation rule and a cost estimation rule; (2) every agent reports her own connection demand as well...... as all connection costs; (3) the central planner selects a cost minimizing network satisfying reported connection demands based on the estimated costs; and, (4) the planner allocates the true costs of the selected network. It turns out that an allocation rule satisfies the axioms if and only if relative...

Survey on nonlocal games and operator space theory

Energy Technology Data Exchange (ETDEWEB)

Palazuelos, Carlos, E-mail: cpalazue@mat.ucm.es [Instituto de Ciencias Matemáticas (ICMAT), Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, Madrid (Spain); Vidick, Thomas, E-mail: vidick@cms.caltech.edu [Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, California 91125 (United States)

2016-01-15

This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states.

Survey on nonlocal games and operator space theory

International Nuclear Information System (INIS)

Palazuelos, Carlos; Vidick, Thomas

2016-01-01

This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states

Scalloped Implant-Abutment Connection Compared to Conventional Flat Implant-Abutment Connection

DEFF Research Database (Denmark)

Starch-Jensen, Thomas; Christensen, Ann-Eva; Lorenzen, Henning

2017-01-01

OBJECTIVES: The objective was to test the hypothesis of no difference in implant treatment outcome after installation of implants with a scalloped implant-abutment connection compared to a flat implant-abutment connection. MATERIAL AND METHODS: A MEDLINE (PubMed), Embase and Cochrane library search......-abutment connection. There were no significant differences between the two treatment modalities regarding professional or patient-reported outcome measures. Meta-analysis disclosed a mean difference of peri-implant marginal bone loss of 1.56 mm (confidence interval: 0.87 to 2.25), indicating significant more bone...... loss around implants with a scalloped implant-abutment connection. CONCLUSIONS: A scalloped implant-abutment connection seems to be associated with higher peri-implant marginal bone loss compared to a flat implant-abutment connection. Therefore, the hypothesis of the present systematic review must...

Connection between perturbation theory, projection-operator techniques, and statistical linearization for nonlinear systems

International Nuclear Information System (INIS)

Budgor, A.B.; West, B.J.

1978-01-01

We employ the equivalence between Zwanzig's projection-operator formalism and perturbation theory to demonstrate that the approximate-solution technique of statistical linearization for nonlinear stochastic differential equations corresponds to the lowest-order β truncation in both the consolidated perturbation expansions and in the ''mass operator'' of a renormalized Green's function equation. Other consolidated equations can be obtained by selectively modifying this mass operator. We particularize the results of this paper to the Duffing anharmonic oscillator equation

Women’s connectivity in extreme networks

Science.gov (United States)

Manrique, Pedro; Cao, Zhenfeng; Gabriel, Andrew; Horgan, John; Gill, Paul; Qi, Hong; Restrepo, Elvira M.; Johnson, Daniela; Wuchty, Stefan; Song, Chaoming; Johnson, Neil

2016-01-01

A popular stereotype is that women will play more minor roles than men as environments become more dangerous and aggressive. Our analysis of new longitudinal data sets from offline and online operational networks [for example, ISIS (Islamic State)] shows that although men dominate numerically, women emerge with superior network connectivity that can benefit the underlying system’s robustness and survival. Our observations suggest new female-centric approaches that could be used to affect such networks. They also raise questions about how individual contributions in high-pressure systems are evaluated. PMID:27386564

Low Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede

2013-01-01

The progressively growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSO) to update or revise the existing grid codes in order to guarantee the availability, quality and reliability of the electrical system. It is expected that the future PV systems connected...... to the low-voltage grid will be more active with functionalities of low voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in low voltage ride through operation in order...... to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability...

Processes meet big data : connecting data science with process science

NARCIS (Netherlands)

van der Aalst, W.; Damiani, E.

2015-01-01

As more and more companies are embracing Big data, it has become apparent that the ultimate challenge is to relate massive amounts of event data to processes that are highly dynamic. To unleash the value of event data, events need to be tightly connected to the control and management of operational

Accelerator operation in 1995-1996

International Nuclear Information System (INIS)

Loyer, F.

1998-01-01

This report presents the operation of the GANIL accelerator between 1995 and 1996. A table is given in which the time distribution of the accelerator operation in the two years is indicated as: beam availability, time devoted to nuclear and non-nuclear physics research, radioactive ion separator operation, industrial irradiation, machine studies and maintenance. A statistics of the accelerated elements and their energy (MeV/u) shows an increase in the number of beam types and new beams from 18 and 9, respectively, in 1995 to 19 and 11 respectively in 1996. The report mentions also the safety incident of June 9, 1995, the failures in operation in 1995-1996 and events connected to SISSI, UGS-R and THI operations

A review of variables of urban street connectivity for spatial connection

International Nuclear Information System (INIS)

Mohamad, W S N W; Said, I

2014-01-01

Several studies on street connectivity in cities and towns have been modeled on topology, morphology, technology and psychology of people living in the urban environment. Street connectivity means the connection of streets that offers people alternative routes. However, there emerge difficulties to determine the suitable variables and analysis to be chosen in defining the accurate result for studies street connectivity. The aim of this paper is to identify variables of street connectivity by applying GIS and Space Syntax. This paper reviews the variables of street connectivity from 15 past articles done in 1990s to early 2000s from journals of nine disciplines on Environment and Behavior, Planning and Design, Computers, Environment and Urban Systems, Applied Earth Observation and Geo-information, Environment and Planning, Physica A: Statistical Mechanics and its Applications, Environmental Psychology, Social Science and Medicine and Building and Environment. From the review, there are four variables found for street connectivity: link (streets-streets, street-nodes or node-streets, nodes-nodes), accessibility, least-angle, and centrality. Space syntax and GIS are suitable tools to analyze the four variables relating to systematic street systems for pedestrians. This review implies that planners of the street systems, in the aspect of street connectivity in cities and towns, should consider these four variables

A review of variables of urban street connectivity for spatial connection

Science.gov (United States)

Mohamad, W. S. N. W.; Said, I.

2014-02-01

Several studies on street connectivity in cities and towns have been modeled on topology, morphology, technology and psychology of people living in the urban environment. Street connectivity means the connection of streets that offers people alternative routes. However, there emerge difficulties to determine the suitable variables and analysis to be chosen in defining the accurate result for studies street connectivity. The aim of this paper is to identify variables of street connectivity by applying GIS and Space Syntax. This paper reviews the variables of street connectivity from 15 past articles done in 1990s to early 2000s from journals of nine disciplines on Environment and Behavior, Planning and Design, Computers, Environment and Urban Systems, Applied Earth Observation and Geo-information, Environment and Planning, Physica A: Statistical Mechanics and its Applications, Environmental Psychology, Social Science and Medicine and Building and Environment. From the review, there are four variables found for street connectivity: link (streets-streets, street-nodes or node-streets, nodes-nodes), accessibility, least-angle, and centrality. Space syntax and GIS are suitable tools to analyze the four variables relating to systematic street systems for pedestrians. This review implies that planners of the street systems, in the aspect of street connectivity in cities and towns, should consider these four variables.

Disease Definition for Schizophrenia by Functional Connectivity Using Radiomics Strategy.

Science.gov (United States)

Cui, Long-Biao; Liu, Lin; Wang, Hua-Ning; Wang, Liu-Xian; Guo, Fan; Xi, Yi-Bin; Liu, Ting-Ting; Li, Chen; Tian, Ping; Liu, Kang; Wu, Wen-Jun; Chen, Yi-Huan; Qin, Wei; Yin, Hong

2018-02-17

Specific biomarker reflecting neurobiological substrates of schizophrenia (SZ) is required for its diagnosis and treatment selection of SZ. Evidence from neuroimaging has implicated disrupted functional connectivity in the pathophysiology. We aimed to develop and validate a method of disease definition for SZ by resting-state functional connectivity using radiomics strategy. This study included 2 data sets collected with different scanners. A total of 108 first-episode SZ patients and 121 healthy controls (HCs) participated in the current study, among which 80% patients and HCs (n = 183) and 20% (n = 46) were selected for training and testing in intra-data set validation and 1 of the 2 data sets was selected for training and the other for testing in inter-data set validation, respectively. Functional connectivity was calculated for both groups, features were selected by Least Absolute Shrinkage and Selection Operator (LASSO) method, and the clinical utility of its features and the generalizability of effects across samples were assessed using machine learning by training and validating multivariate classifiers in the independent samples. We found that the accuracy of intra-data set training was 87.09% for diagnosing SZ patients by applying functional connectivity features, with a validation in the independent replication data set (accuracy = 82.61%). The inter-data set validation further confirmed the disease definition by functional connectivity features (accuracy = 83.15% for training and 80.07% for testing). Our findings demonstrate a valid radiomics approach by functional connectivity to diagnose SZ, which is helpful to facilitate objective SZ individualized diagnosis using quantitative and specific functional connectivity biomarker.

Clinical application of MSCT in the diagnosis of anomalous pulmonary venous connection in infants and children

International Nuclear Information System (INIS)

Huang Meiping; Liang Changhong; Zeng Hui; Liu Qishun; Zhang Zhonglin; Zhang Jin'e; Huang Biao

2005-01-01

Objective: To investigate the clinical usefulness of multislice computed tomography (MSCT) in the diagnosis of anomalous pulmonary venous connection in infants and children. Methods: Retrospective analysis on 20 cases with anomalous pulmonary venous connection was performed using contrast-enhanced MSCT volume scan. The age ranged from 11 days to 12 years. The slice thickness and slice interval were 1.250 mm and 0.625 mm, respectively. Three-dimensional reconstructions were performed with multiplanar reformation (MPR), sliding thin-slabmaximum intensity projection (STS-MIP), volume rendering (VR), and shade-surface displayment (SSD). Ultrasound echocardiography (US) was performed in all patients. Conventional cardiovascular angiography (CAG) was performed in 12 patients, and 14 cased received operation. Results: Of the 20 patients received MSCT, total anomalous pulmonary venous connection was diagnosed in 9, and partial anomalous pulmonary venous connection in 11, including supracardiac type (n=5), cardiac type (n=10), infracardiac type (n=4), and mixed type (n=1). MSCT clearly displayed the number, distribution, and location of anomalous pulmonary venous connection in all patients. Among them, the misdiagnosis by CAG and US were encountered in 3 cases and 10 cases, respectively. The diagnosis by MSCT was compatible with the operative findings in all 14 patients receiving surgery. Conclusion: MSCT has significant value in the diagnosis of pediatric anomalous pulmonary venous connection which may not be detectable with echocardiography or even cardiovascular angiography. (authors)

CoNNeCT Antenna Positioning System Dynamic Simulator Modal Model Correlation

Science.gov (United States)

Jones, Trevor M.; McNelis, Mark E.; Staab, Lucas D.; Akers, James C.; Suarez, Vicente J.

2012-01-01

The National Aeronautics and Space Administration (NASA) developed an on-orbit, adaptable, Software Defined Radios (SDR)/Space Telecommunications Radio System (STRS)-based testbed facility to conduct a suite of experiments to advance technologies, reduce risk, and enable future mission capabilities on the International Space Station (ISS). The Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) Project will provide NASA, industry, other Government agencies, and academic partners the opportunity to develop and field communications, navigation, and networking technologies in both the laboratory and space environment based on reconfigurable, software-defined radio platforms and the STRS Architecture. The CoNNeCT Payload Operations Nomenclature is SCAN Testbed, and this nomenclature will be used in all ISS integration, safety, verification, and operations documentation. The SCAN Testbed (payload) is a Flight Releasable Attachment Mechanism (FRAM) based payload that will launch aboard the Japanese H-II Transfer Vehicle (HTV) Multipurpose Exposed Pallet (EP-MP) to the International Space Station (ISS), and will be transferred to the Express Logistics Carrier 3 (ELC3) via Extravehicular Robotics (EVR). The SCAN Testbed will operate on-orbit for a minimum of two years.

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...

A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

OpenAIRE

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Track...

Harmonic Instability Analysis of Single-Phase Grid Connected Converter using Harmonic State Space (HSS) modeling method

DEFF Research Database (Denmark)

Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

2015-01-01

The increasing number of renewable energy sources at the distribution grid is becoming a major issue for utility companies, since the grid connected converters are operating at different operating points due to the probabilistic characteristics of renewable energy. Besides, typically, the harmonics...... proposes a new model of a single phase grid connected renewable energy source using the Harmonic State Space modeling approach, which is able to identify such problems and the model can be extended to be applied in the multiple connected converter analysis. The modeling results show the different harmonic...... and impedance from other renewable energy sources are not taken carefully into account in the installation and design. However, this may bring an unknown harmonic instability into the multiple power sourced system and also make the analysis difficult due to the complexity of the grid network. This paper...

Hydraulic screw fastening devices - design, maintenance, operational experience

International Nuclear Information System (INIS)

Lachner.

1976-01-01

With hydraulic screw fastening devices, pretension values with a maximum deviation of +-2.5% from the rated value can be achieved. This high degree of pretension accuracy is of considerable importance with regard to the safety factor required for the screw connection between reactor vessel head and reactor vessel. The operating rhythm of a nuclear power station with its refuelling art regular intervals makes further demands on the screw fastening device, in particular in connection with the transport of screws and for nuts. The necessary installations extend the screw fastening device into a combination of a high-pressure hydraulic cylinder system with an electrical or pneumoelectrical driving unit and an electrical control unit. Maintenance work is complicated by the large number of identical, highly stressed structural elements in connection with an unfavourable relation operating time/outage time. The problems have been perpetually reduced by close cooperation between the manufacturers and users of screw fastening devices. (orig./AK) [de

Connecting Grammaticalisation

DEFF Research Database (Denmark)

Nørgård-Sørensen, Jens; Heltoft, Lars; Schøsler, Lene

morphological, topological and constructional paradigms often connect to form complex paradigms. The book introduces the concept of connecting grammaticalisation to describe the formation, restructuring and dismantling of such complex paradigms. Drawing primarily on data from Germanic, Romance and Slavic...

ALARA for nuclear power plant operation

International Nuclear Information System (INIS)

Knapp, P.J.

1979-01-01

The concept of maintaining radiation exposures as low as reasonably achievable (ALARA) is outlined in connection with nuclear power plant operations. The basis of the concept is reviewed and a specific example of ALARA action is presented. (author)

Expected Range of Cooperation Between Transmission System Operators and Distribution System Operators After Implementation of ENTSO-E Grid Codes

Directory of Open Access Journals (Sweden)

Tomasz Pakulski

2015-06-01

Full Text Available The authors present the prospects of cooperation between transmission system operators (TSO and distribution system operators (DSO after entry into force ENTSO-E (European Network of Transmission System Operators for Electricity grid codes. New areas of DSO activities, associated with offering TSO aggregated services for national power system regulation based on the regulation resources connected to the distribution grid, and services on the distribution system level as part of the creation of local balancing areas (LBA are presented. The paper also presents the possibilities of providing ancillary services by different types of distributed generation sources in the distribution network. The LBA concept, which involves integrated management of local regulation resources including generation, demand, and energy storage is described. The options of the renewable energy sources (RES using for voltage and reactive power control in the distribution network with the use of wind farms (WF connected to the distribution system are characterized.

42 CFR 84.145 - Motor-operated blower test; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Motor-operated blower test; minimum requirements... Supplied-Air Respirators § 84.145 Motor-operated blower test; minimum requirements. (a) Motor-operated... connection between the motor and the blower shall be so constructed that the motor may be disengaged from the...

From capture to simulation: connecting forward and inverse problems in fluids

KAUST Repository

Gregson, James; Ihrke, Ivo; Thuerey, Nils; Heidrich, Wolfgang

2014-01-01

We explore the connection between fluid capture, simulation and proximal methods, a class of algorithms commonly used for inverse problems in image processing and computer vision. Our key finding is that the proximal operator constraining fluid velocities to be divergence-free is directly equivalent to the pressure-projection methods commonly used in incompressible flow solvers. This observation lets us treat the inverse problem of fluid tracking as a constrained flow problem all while working in an efficient, modular framework. In addition it lets us tightly couple fluid simulation into flow tracking, providing a global prior that significantly increases tracking accuracy and temporal coherence as compared to previous techniques. We demonstrate how we can use these improved results for a variety of applications, such as re-simulation, detail enhancement, and domain modification. We furthermore give an outlook of the applications beyond fluid tracking that our proximal operator framework could enable by exploring the connection of deblurring and fluid guiding.

From capture to simulation: connecting forward and inverse problems in fluids

KAUST Repository

Gregson, James

2014-07-27

We explore the connection between fluid capture, simulation and proximal methods, a class of algorithms commonly used for inverse problems in image processing and computer vision. Our key finding is that the proximal operator constraining fluid velocities to be divergence-free is directly equivalent to the pressure-projection methods commonly used in incompressible flow solvers. This observation lets us treat the inverse problem of fluid tracking as a constrained flow problem all while working in an efficient, modular framework. In addition it lets us tightly couple fluid simulation into flow tracking, providing a global prior that significantly increases tracking accuracy and temporal coherence as compared to previous techniques. We demonstrate how we can use these improved results for a variety of applications, such as re-simulation, detail enhancement, and domain modification. We furthermore give an outlook of the applications beyond fluid tracking that our proximal operator framework could enable by exploring the connection of deblurring and fluid guiding.

How do strategic decisions and operative practices affect operating room productivity?

Science.gov (United States)

Peltokorpi, Antti

2011-12-01

Surgical operating rooms are cost-intensive parts of health service production. Managing operating units efficiently is essential when hospitals and healthcare systems aim to maximize health outcomes with limited resources. Previous research about operating room management has focused on studying the effect of management practices and decisions on efficiency by utilizing mainly modeling approach or before-after analysis in single hospital case. The purpose of this research is to analyze the synergic effect of strategic decisions and operative management practices on operating room productivity and to use a multiple case study method enabling statistical hypothesis testing with empirical data. 11 hypotheses that propose connections between the use of strategic and operative practices and productivity were tested in a multi-hospital study that included 26 units. The results indicate that operative practices, such as personnel management, case scheduling and performance measurement, affect productivity more remarkably than do strategic decisions that relate to, e.g., units' size, scope or academic status. Units with different strategic positions should apply different operative practices: Focused hospital units benefit most from sophisticated case scheduling and parallel processing whereas central and ambulatory units should apply flexible working hours, incentives and multi-skilled personnel. Operating units should be more active in applying management practices which are adequate for their strategic orientation.

Smart Inverter Control and Operation for Distributed Energy Resources

Science.gov (United States)

Tazay, Ahmad F.

The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1. Low-level control of a single smart Inverter. 2. High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of

Connected vehicle pilot deployment program phase I : security management operational concept, Tampa Hillsborough Expressway Authority (THEA).

Science.gov (United States)

2016-05-01

The Tampa Hillsborough Expressway Authority (THEA) Connected Vehicle (CV) Pilot Deployment Program is intended to develop a suite of applications that utilize vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) communication technology to re...

PG&E WaveConnect Program Final Report

Energy Technology Data Exchange (ETDEWEB)

Brendan P. Dooher; Edward Cheslak; Robert Booth; Doug Davy; Annette Faraglia; Ian Caliendo; Gina Morimoto; Douglas Herman

2011-12-01

The PG&E WaveConnect project was intended to demonstrate the technical and economic viability of wave power in the open ocean adjacent to PG&E's service territory. WaveConnect was conceived as a multi-stage development process leading to long-term megawatt-scale wave power production. The first-stage tasks consisted of site selection, permitting, pilot plant design, and assessment of technology and commercial readiness. The second stage would have included development of infrastructure, undersea cabling, and deployment of wave energy conversion devices (WECs). In the third stage, the most promising WEC devices would have been deployed in larger quantities and connected to the grid. This report documents the findings of Stage One. Site Selection: After studying the wave energy potential, grid interconnection and other project infrastructure along the California coast, PG&E selected two sites: one near Eureka, called the Humboldt WaveConnect (HWC) project, and another near Vandenberg Air Force Base, called the Central Coast WaveConnect project (CCWC). Permitting: FERC issued PG&E preliminary permits for HWC in 2008 and for CCWC in 2010. PG&E chose to use FERC's Pilot Project Licensing Process, which was intended to streamline licensing to allow relatively quick and easy installation, operation, and environmental testing for pilot projects. Permitting, however, proved to be complicated, time-consuming and expensive, mainly because of the uncertain impacts of WEC devices. PG&E learned that even under the PPLP the project would still require a full analysis under CEQA, including an EIR, as well as Monitoring and Adaptive Management Programs and other requirements that had significant cost and scheduling implications. A majority of efforts were expended on permitting activities. Pilot Plant Design: PG&E prepared a conceptual design for a 5-MW pilot test facility at the Humboldt site, which consisted of an off-shore deployment area where WECs of different

Private quantum subsystems and quasiorthogonal operator algebras

International Nuclear Information System (INIS)

Levick, Jeremy; Kribs, David W; Pereira, Rajesh; Jochym-O’Connor, Tomas; Laflamme, Raymond

2016-01-01

We generalize a recently discovered example of a private quantum subsystem to find private subsystems for Abelian subgroups of the n-qubit Pauli group, which exist in the absence of private subspaces. In doing so, we also connect these quantum privacy investigations with the theory of quasiorthogonal operator algebras through the use of tools from group theory and operator theory. (paper)

Ideals in algebras of unbounded operators

International Nuclear Information System (INIS)

Timmermann, W.

1977-01-01

The paper presents a continuation of investigations on ideals in algebras of unbounded operators. A general procedure is given to get ideals in L + (D) starting with ideals in B(H). A definition of the two types of ideals is given: one contains only bounded operators, the other involves both bounded and unbounded operators. Some algebraic properties of ideals Ssub(phi)(D) derived from the well-known symmetrically normed ideals Ssub(phi) are investigated. Topologies in such ideals are introduced, and some results connected with topological properties of these ideals are given

The German experience with grid-connected PV-systems

International Nuclear Information System (INIS)

Erge, T.; Hoffmann, V.U.; Kiefer, K.

2001-01-01

Grid-connected photovoltaics experienced increasing attention in Germany in recent years and are expected to face a major boost at the beginning of the new millennium. Highlights like the German 100,000-Roofs-Solar-Programme, PV programmes at schools financed by utilities and governments (e.g. 'SONNEonline' by PreussenElektra, 'Sonne in der Schule' by BMWi and 'Sonne in der Schule' by Bayernwerk) and large centralised installations of MW size ('Neue Messe Munchen' by Bayernwerk and 'Energiepark Mont-Cenis' by state Nordrhein-Westfalen, Stadtwerke Herne and European Union) count for the potential of grid-connected PV. Today in Germany a typical grid-connected PV installation of 1 kW nominal power produces average annual energy yields of 700 kWh (dependent on location and system components) and shows a high operating availability. The price per kWh from PV installations is still significantly higher than the price for conventional energy, but new funding schemes and cost models (like the large increase of feed-in tariff in Germany due to the Act on Granting Priority to Renewable Energy Sources in 2000) give optimism about the future. (Author)

A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... performed on a 3-kW two-stage single-phase grid-connected PV system, where the power reserve control is achieved upon demands....

Conditions and costs for renewables electricity grid connection: Examples in Europe

International Nuclear Information System (INIS)

Swider, Derk J.; Beurskens, Luuk; Davidson, Sarah; Twidell, John; Pyrko, Jurek; Prueggler, Wolfgang; Auer, Hans; Vertin, Katarina; Skema, Romualdas

2008-01-01

This paper compares conditions and costs for RES-E grid connection in selected European countries. These are Germany, the Netherlands, the United Kingdom, Sweden, Austria, Lithuania and Slovenia. Country specific case studies are presented for wind onshore and offshore, biomass and photovoltaic power systems, as based on literature reviews and stakeholder interviews. It is shown that, especially for wind offshore, the allocation of grid connection costs can form a significant barrier for the installation of new RES-E generation if the developer has to bear all such costs. If energy policy makers want to reduce the barriers for new large-scale RES-E deployment, then it is concluded that the grid connection costs should be covered by the respective grid operator. These costs may then be recouped by increasing consumer tariffs for the use of the grid. (author)

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

DEFF Research Database (Denmark)

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

2015-01-01

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

Delta Power Control Strategy for Multi-String Grid-Connected PV Inverters

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

With a still increasing penetration level of grid-connected PV systems, more advanced active power control functionalities have been introduced in certain grid regulations. A delta power constraint, where a portion of the active power from the PV panels is reserved during operation, is required...... for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control for grid-connected PV systems is presented, where the residential/commercial multi-string PV inverter configuration is adopted. This control strategy is a combination of Maximum...... for the entire PV system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the delta power control strategy, where the power reserve according to the delta power constraint is achieved under several...

Wireless Impedance-Based SHM for Bolted Connections via Multiple PZT-Interfaces

International Nuclear Information System (INIS)

Nguyen, Khac Duy; Kim, Jeong Tae

2011-01-01

This study presents a structural health monitoring(SHM) method for bolted connections by using multi-channel wireless impedance sensor nodes and multiple PZT-interfaces. To achieve the objective, the following approaches are implemented. Firstly, a PZT-interface is designed to monitor bolt loosening in bolted connection based on variation of electro-mechanical(EM) impedance signatures. Secondly, a wireless impedance sensor node is designed for autonomous, cost-efficient and multi-channel monitoring. For the sensor platform, Imote2 is selected on the basis of its high operating speed, low power requirement and large storage memory. Finally, the performance of the wireless sensor node and the PZT-interfaces is experimentally evaluated for a bolt-connection model. Damage monitoring method using root mean square deviation(RMSD) index of EM impedance signatures is utilized to estimate the strength of the bolted joint

Quick connect fastener

Science.gov (United States)

Weddendorf, Bruce

1994-01-01

A quick connect fastener and method of use is presented wherein the quick connect fastener is suitable for replacing available bolts and screws, the quick connect fastener being capable of installation by simply pushing a threaded portion of the connector into a member receptacle hole, the inventive apparatus being comprised of an externally threaded fastener having a threaded portion slidably mounted upon a stud or bolt shaft, wherein the externally threaded fastener portion is expandable by a preloaded spring member. The fastener, upon contact with the member receptacle hole, has the capacity of presenting cylindrical threads of a reduced diameter for insertion purposes and once inserted into the receiving threads of the receptacle member hole, are expandable for engagement of the receptacle hole threads forming a quick connect of the fastener and the member to be fastened, the quick connect fastener can be further secured by rotation after insertion, even to the point of locking engagement, the quick connect fastener being disengagable only by reverse rotation of the mated thread engagement.

Increased connectivity between sensorimotor and attentional areas in Parkinson's disease

International Nuclear Information System (INIS)

Onu, Mihaela; Badea, Liviu; Roceanu, Adina; Bajenaru, Ovidiu; Tivarus, Madalina

2015-01-01

Our study is using Independent Component Analysis (ICA) to evaluate functional connectivity changes in Parkinson's disease (PD) in an unbiased manner. Resting-state functional magnetic resonance imaging (rs-fMRI) data was collected for 27 PD patients and 16 healthy subjects. Differences for intra- and inter-network connectivity between healthy subjects and patients were investigated using FMRIB Software Library (FSL) tools (Melodic ICA, dual regression, FSLNets). Twenty-three ICA maps were identified as components of neuronal origin. For intra-network connectivity changes, eight components showed a significant connectivity increase in patients (p < 0.05); these were correlated with clinical scores and were largest for (sensori)motor networks. For inter-network connectivity changes, we found higher connectivity between the sensorimotor network and the spatial attention network (p = 0.0098) and lower connectivity between anterior and posterior default mode networks (DMN) (p = 0.024), anterior DMN and visual recognition networks (p = 0.026), as well as between visual attention and main dorsal attention networks (p = 0.03), for patients as compared to healthy subjects. The area under the Receiver Operating Characteristics (ROC) curve for the best predictor (partial correlation between sensorimotor and spatial attention networks) was 0.772. These functional alterations were not associated with any gray or white matter structural changes. Our results show higher connectivity between sensorimotor and spatial attention areas in patients that may be related to the reduced movement automaticity in PD. (orig.)

Increased connectivity between sensorimotor and attentional areas in Parkinson's disease

Energy Technology Data Exchange (ETDEWEB)

Onu, Mihaela [Medical Imaging Department, Clinical Hospital ' ' Prof. Dr. Th. Burghele' ' , Bucharest (Romania); Carol Davila University of Medicine and Pharmacy, Biophysics, Bucharest (Romania); Badea, Liviu [National Institute for Research and Development in Informatics, Artificial Intelligence and Bioinformatics Group, Bucharest (Romania); Roceanu, Adina; Bajenaru, Ovidiu [University of Bucharest Emergency Hospital, Neurology Department, Bucharest (Romania); Tivarus, Madalina [University of Rochester Medical Center, Department of Imaging Sciences and Rochester Center for Brain Imaging, Rochester, NY (United States)

2015-09-15

Our study is using Independent Component Analysis (ICA) to evaluate functional connectivity changes in Parkinson's disease (PD) in an unbiased manner. Resting-state functional magnetic resonance imaging (rs-fMRI) data was collected for 27 PD patients and 16 healthy subjects. Differences for intra- and inter-network connectivity between healthy subjects and patients were investigated using FMRIB Software Library (FSL) tools (Melodic ICA, dual regression, FSLNets). Twenty-three ICA maps were identified as components of neuronal origin. For intra-network connectivity changes, eight components showed a significant connectivity increase in patients (p < 0.05); these were correlated with clinical scores and were largest for (sensori)motor networks. For inter-network connectivity changes, we found higher connectivity between the sensorimotor network and the spatial attention network (p = 0.0098) and lower connectivity between anterior and posterior default mode networks (DMN) (p = 0.024), anterior DMN and visual recognition networks (p = 0.026), as well as between visual attention and main dorsal attention networks (p = 0.03), for patients as compared to healthy subjects. The area under the Receiver Operating Characteristics (ROC) curve for the best predictor (partial correlation between sensorimotor and spatial attention networks) was 0.772. These functional alterations were not associated with any gray or white matter structural changes. Our results show higher connectivity between sensorimotor and spatial attention areas in patients that may be related to the reduced movement automaticity in PD. (orig.)

THE ANALYSIS OF STRUCTURAL RELIABILITY OF THE MAIN ELECTRIC CONNECTION CIRCUITS OF NUCLEAR POWER PLANTS

Directory of Open Access Journals (Sweden)

M. A. Korotkevich

2017-01-01

Full Text Available The reliability of the main circuit of electrical connections at a nuclear electric power plant that has two units with a capacity of 1,200 MW each has been determined. Reliability, economical, maneuverable properties of the atomic power plant under study are largely determined by its main circuit, so the choice of the circuit for the design and its status in the process of operation occur to be critical objectives. Main electrical connection circuits in nuclear electric power plants are selected on the basis of the schematic networks of the energy system and the land attached to the plant. The circuit of the connection of a nuclear power plant to the grid in the original normal operating modes at all stages of the construction of such a plant should provide the outcome of the full added capacity of a nuclear power plant and the preservation of its stability in the power system without the influence of the emergency system automatics when any outgoing transmission line is disabled. When selecting the main circuit the individual capacity of the installed units and their number are taken into account as well as the order of development of the plant and power supply system; the voltage on which the power of a plant is delivered; a shortcircuit current for switchgear high voltage and the need for their limitation by circuit means; the most power that can be lost when damage to any switch. A model of reliability of the main circuit of electrical connections is designed to detect all types of accidents that are possible at the coincidence of failures of elements with the repair and operational modes that differs in composition and damageability of the equipment, as well as under conditions of the development of accidents due to failure of operation of devices of relay protection and automation.

Distributed generation connected to the local network - a guide

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This guide provides advice to the developers and operators of small distributed generation plant (including microgenerators) in the UK about the practical issues associated with connecting their plant and trading their output. Particular attention is given to sales revenues and how to access these revenue streams, including the mechanisms for purchasing Renewable Obligation Certificates (ROCs). The guide clarifies key terms, explains the wholesale trading system and provides an overview of sales opportunities (including ROCs and Levy Exemption Certificates (LECs)). Requirements on small distributed generation (including licensing, claiming class exemptions and metering) are described and the commercial aspects of connection (including the recent reduction in the barriers to connection) examined. Microgeneration (ie generators below 10 kW) issues are covered in their own chapter. The six appendices contain: background information about the industry; a list of purchasers of electricity from small distributed generators; descriptions of the generation, transmission and supply industries; information about industry standards and their governance; the role of government departments and institutions; and a glossary and other links.

The Ionospheric Connection Explorer Mission: Mission Goals and Design

Science.gov (United States)

Immel, T. J.; England, S. L.; Mende, S. B.; Heelis, R. A.; Englert, C. R.; Edelstein, J.; Frey, H. U.; Korpela, E. J.; Taylor, E. R.; Craig, W. W.; Harris, S. E.; Bester, M.; Bust, G. S.; Crowley, G.; Forbes, J. M.; Gérard, J.-C.; Harlander, J. M.; Huba, J. D.; Hubert, B.; Kamalabadi, F.; Makela, J. J.; Maute, A. I.; Meier, R. R.; Raftery, C.; Rochus, P.; Siegmund, O. H. W.; Stephan, A. W.; Swenson, G. R.; Frey, S.; Hysell, D. L.; Saito, A.; Rider, K. A.; Sirk, M. M.

2018-02-01

The Ionospheric Connection Explorer, or ICON, is a new NASA Explorer mission that will explore the boundary between Earth and space to understand the physical connection between our world and our space environment. This connection is made in the ionosphere, which has long been known to exhibit variability associated with the sun and solar wind. However, it has been recognized in the 21st century that equally significant changes in ionospheric conditions are apparently associated with energy and momentum propagating upward from our own atmosphere. ICON's goal is to weigh the competing impacts of these two drivers as they influence our space environment. Here we describe the specific science objectives that address this goal, as well as the means by which they will be achieved. The instruments selected, the overall performance requirements of the science payload and the operational requirements are also described. ICON's development began in 2013 and the mission is on track for launch in 2018. ICON is developed and managed by the Space Sciences Laboratory at the University of California, Berkeley, with key contributions from several partner institutions.

Analysis of Data Interruption in an LTE Highway Scenario with Dual Connectivity

DEFF Research Database (Denmark)

Gimenez, Lucas Chavarria; Michaelsen, Per-Henrik; Pedersen, Klaus I.

2016-01-01

This study evaluates whether last versions of Long Term Evolution with dual connectivity are able to support the latency and reliability requirements for the upcoming vehicular use-cases and time-critical applications. Data interruption times during handovers and cell management operations are ev...

New grid-planning and certification approaches for the large-scale offshore-wind farm grid-connection systems

Energy Technology Data Exchange (ETDEWEB)

Heising, C.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Zadeh, M. Koochack; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

2012-07-01

Stable operation of the offshore-wind farms (OWF) and stable grid connection under stationary and dynamic conditions are essential to achieve a stable public power supply. To reach this aim, adequate grid-planning and certification approaches are a major advantage. Within this paper, the fundamental characteristics of the offshore-wind farms and their grid-connection systems are given. The main goal of this research project is to study the stability of the offshore grid especially in terms of subharmonic stability for the likely future extension stage of the offshore grids i.e. having parallel connection of two or more HVDC links and for certain operating scenarios e.g. overload scenario. The current requirements according to the grid code are not the focus of this research project. The goal is to study and define potential additional grid code requirements, simulations, tests and grid planning methods for the future. (orig.)

Grid connection of active stall wind farms using a VSC based DC transmission system

DEFF Research Database (Denmark)

Iov, F.; Sørensen, Poul Ejnar; Hansen, A.D.

2005-01-01

Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Requirements that focus on the influence of the farms on the grid stability and power quality, and on the control capabilities of wind farms have already been established. The main trends of modern...... wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...

Some connections for manuals of empirical logic to functional analysis

International Nuclear Information System (INIS)

Cook, T.A.

1981-01-01

In this informal presentation, the theory of manuals of operations is connected with some familiar concepts in functional analysis; namely, base normed and order unit normed spaces. The purpose of this discussion is to present several general open problems which display the interplay of empirical logic with functional analysis. These are mathematical problems with direct physical interpretation. (orig./HSI)

Short-circuit testing of monofilar Bi-2212 coils connected in series and in parallel

International Nuclear Information System (INIS)

Polasek, A; Dias, R; Serra, E T; Filho, O O; Niedu, D

2010-01-01

Superconducting Fault Current Limiters (SCFCL's) are one of the most promising technologies for fault current limitation. In the present work, resistive SCFCL components based on Bi-2212 monofilar coils are subjected to short-circuit testing. These SCFCL components can be easily connected in series and/or in parallel by using joints and clamps. This allows a considerable flexibility to developing larger SCFCL devices, since the configuration and size of the whole device can be easily adapted to the operational conditions. The single components presented critical current (Ic) values of 240-260 A, at 77 K. Short-circuits during 40-120 ms were applied. A single component can withstand a voltage drop of 126-252 V (0.3-0.6 V/cm). Components connected in series withstand higher voltage levels, whereas parallel connection allows higher rated currents during normal operation, but the limited current is also higher. Prospective currents as high as 10-40 kA (peak value) were limited to 3-9 kA (peak value) in the first half cycle.

Connecting section and associated systems concept for the spray calciner/in-can melter process

International Nuclear Information System (INIS)

Petkus, L.L.; Gorton, P.S.; Blair, H.T.

1981-06-01

For a number of years, researchers at the Pacific Northwest Laboratory have been developing processes and equipment for converting high-level liquid wastes to solid forms. One of these processes is the Spray Calciner/In-Can Melter system. To immobilize high-level liquid wastes, this system must be operated remotely, and the calcine must be reliably conveyed from the calciner to the melting furnace. A concept for such a remote conveyance system was developed at the Pacific Northwest Laboratory, and equipment was tested under full-scale, nonradioactive conditions. This concept and the design of demonstration equipment are described, and the results of equipment operation during experimental runs of 7 d are presented. The design includes a connecting section and its associated systems - a canister sypport and alignment concept and a weight-monitoring system for the melting furnace. Overall, the runs demonstrated that the concept design is an acceptable method of connecting the two pieces of process equipment together. Although the connecting section has not been optimized in all areas of concern, it provides a first-generation design of a production-oriented system

Scalloped Implant-Abutment Connection Compared to Conventional Flat Implant-Abutment Connection

DEFF Research Database (Denmark)

Starch-Jensen, Thomas; Christensen, Ann-Eva; Lorenzen, Henning

2017-01-01

OBJECTIVES: The objective was to test the hypothesis of no difference in implant treatment outcome after installation of implants with a scalloped implant-abutment connection compared to a flat implant-abutment connection. MATERIAL AND METHODS: A MEDLINE (PubMed), Embase and Cochrane library search...... of suprastructures has never been compared within the same study. High implant survival rate was reported in all the included studies. Significantly more peri-implant marginal bone loss, higher probing depth score, bleeding score and gingival score was observed around implants with a scalloped implant-abutment...... loss around implants with a scalloped implant-abutment connection. CONCLUSIONS: A scalloped implant-abutment connection seems to be associated with higher peri-implant marginal bone loss compared to a flat implant-abutment connection. Therefore, the hypothesis of the present systematic review must...

Special Operations can make a difference in integrated conflict prevention

DEFF Research Database (Denmark)

Jensen, Lars H. Ehrensvärd

The fifth brief in the series about special operations highlights the possible strategic role of special operations in connection with Denmark's revitalized vision of integration of the state's instruments to create security through preventive stabilization efforts. The brief offers suggestion...

9 Office of Regions and Center Operations LANS -

Data.gov (United States)

Department of Transportation — The 9 Office of Regions and Center Operations LANS located at regional offices is the backbone that provides connectivity to systems including servers, workstations,...

Effect of grid disturbances on fault-ride-through behaviour of MV-connected DG-units, in especially CHP-plants

NARCIS (Netherlands)

Coster, E.J.; Myrzik, J.M.A.; Kling, W.L.

2009-01-01

In the near future a significant amount of the consumed electrical energy will be generated by distributed generation (DG). Because of the small size these units are normally connected to the local distribution grid [1]. Connection of DG changes the operation of the distribution grid. In order to

THE CONNECTION BETWEEN MANAGEMENT AND TECHNOLOGY AND THE TECHNOLOGICAL MANAGEMENT

Directory of Open Access Journals (Sweden)

RAREŞ MUNTEANU

2010-01-01

Full Text Available In a new approach, the technology is taken into consideration as a resource of the business, in addition to the four traditional resources: material resources, financial resources, human resources and informational resources. This makes important for the managers to have solid technological knowledge, in addition to the economics. The research regarding the technological management (or the management of technology - MOT is lead by IAMOT (International Association in Management of Technology. There are a lot of connections between the technology on one side and the finances, the human resources, the marketing, the operational management on the other side. In our era the technology is more and more advanced and all the activities are strongly connected to it.

Detecting Functional Connectivity During Audiovisual Integration with MEG: A Comparison of Connectivity Metrics.

Science.gov (United States)

Ard, Tyler; Carver, Frederick W; Holroyd, Tom; Horwitz, Barry; Coppola, Richard

2015-08-01

In typical magnetoencephalography and/or electroencephalography functional connectivity analysis, researchers select one of several methods that measure a relationship between regions to determine connectivity, such as coherence, power correlations, and others. However, it is largely unknown if some are more suited than others for various types of investigations. In this study, the authors investigate seven connectivity metrics to evaluate which, if any, are sensitive to audiovisual integration by contrasting connectivity when tracking an audiovisual object versus connectivity when tracking a visual object uncorrelated with the auditory stimulus. The authors are able to assess the metrics' performances at detecting audiovisual integration by investigating connectivity between auditory and visual areas. Critically, the authors perform their investigation on a whole-cortex all-to-all mapping, avoiding confounds introduced in seed selection. The authors find that amplitude-based connectivity measures in the beta band detect strong connections between visual and auditory areas during audiovisual integration, specifically between V4/V5 and auditory cortices in the right hemisphere. Conversely, phase-based connectivity measures in the beta band as well as phase and power measures in alpha, gamma, and theta do not show connectivity between audiovisual areas. The authors postulate that while beta power correlations detect audiovisual integration in the current experimental context, it may not always be the best measure to detect connectivity. Instead, it is likely that the brain utilizes a variety of mechanisms in neuronal communication that may produce differential types of temporal relationships.

Conceptual design of a connected vehicle wrong-way driving detection and management system.

Science.gov (United States)

2016-04-01

This report describes the tasks completed to develop a concept of operations, functional requirements, and : high-level system design for a Connected Vehicle (CV) Wrong-Way Driving (WWD) Detection and Management : System. This system was designed to ...

Method for extending the unrestricted operating range of condensing steam turbines

International Nuclear Information System (INIS)

Csaba, G.; Bannerth, Cs.

2009-01-01

The allowed condenser temperature of the condensing steam turbines is determined by the design parameters of the steam turbine (casing geometry, exhaust area, blade length, blade angle, blade profile etc.). The fluctuations of condenser temperature may lead to reduced power output of the condensing steam turbine. Solutions where the low pressure turbine casings have the same exhaust area can be kept in operation at narrow condenser temperature range without restrictions. Exceeding the mentioned temperature range the exhaust hood temperature restriction, undergoing the temperature range choking point restriction appears causing increased operation cost. The aim of the paper is to present a condensing steam turbine - direct-contact condenser system that can extend the unrestricted operating range. The examined system consists of more parallelly connected low pressure turbine casings so-called diabolo that having at least two exhausts separated at the steam side. The exhausts, utilizing varying input-temperature coolant, are connected to the condensers that are separated at the steam side and serially connected at the coolant side. The casings have the same inlet areas while the exhausts have different areas resulting different volume flows and temperature operating range. The economic advantage of this solution approaches the savings between the serially connected direct-contact condensers and condensers in parallel of a dry cooling system. It can be proven by a simple calculation using the ambient air temperature duration diagram that is presented in the paper. (author)

Intelligent Scheduling of a Grid-Connected Heat Pump in a Danish Detached House

DEFF Research Database (Denmark)

Gianniou, Panagiota; Foteinaki, Kyriaki; Heller, Alfred

This study proposes a methodology for intelligent scheduling of a heat pump installed in a refurbished grid-connected detached house in Denmark. This scheduling is conducted through the coupling of a dynamic building simulation tool with an optimization tool. The optimization of the operation of ...... thermal comfort conditions. The proposed methodology bridges dynamic building modelling with optimization of real-time operation of HVAC systems offering a detailed model for building physics, especially regarding thermal mass and a stochastic price-based control....... of the system is based on a price-signal considering a three-day period for different weather cases. The results show that the optimal scheduling of the system is successful in terms of reducing the peak load during times when electricity prices are high, thus achieving cost savings as well as maintaining good......This study proposes a methodology for intelligent scheduling of a heat pump installed in a refurbished grid-connected detached house in Denmark. This scheduling is conducted through the coupling of a dynamic building simulation tool with an optimization tool. The optimization of the operation...

Mathematical model validation of a thermal architecture system connecting east/west radiators by flight data

International Nuclear Information System (INIS)

Torres, Alejandro; Mishkinis, Donatas; Kaya, Tarik

2014-01-01

A novel satellite thermal architecture connecting the east and west radiators of a geostationary telecommunication satellite via loop heat pipes (LHPs) is flight tested on board the satellite Hispasat 1E. The LHP operating temperature is regulated by using pressure regulating valves (PRVs). The flight data demonstrated the successful operation of the proposed concept. A transient numerical model specifically developed for the design of this system satisfactorily simulated the flight data. The validated mathematical model can be used to design and analyze the thermal behavior of more complex architectures. - Highlights: •A novel spacecraft thermal control architecture is presented. •The east–west radiators of a GEO communications satellite are connected using LHPs. •A transient mathematical model is validated with flight data. •The space flight data proved successful in-orbit operation of the novel architecture. •The model can be used to design/analyze LHP based complex thermal architectures

Pre-operative irradiation of eosinophilic granuloma in the parotid area

International Nuclear Information System (INIS)

Kitahara, Satoshi; Toda, Yukio; Nakajima, Hisami; Takeyama, Isamu; Sodemoto, Yukio; Endo, Masaru

1983-01-01

Eosinophilic granuloma is thought to originate in the reticuloendothelial system and cannot clearly be distinguished from the surrounding tissue during operation. An eosinophilic granuloma in the parotid area was removed after 25 days of irradiation at a dosage of 10.0 Gy per 3 days. A thin capsule of connective tissue was observed after the tumor was cut in half. Then, histopathological studies were performed on this connective tissue to determine the effect of the irradiation. Histopathologically, at the periphery of the tissue, atrophy of lymphocytes and destruction of the lymphoid tissue, which were thought to result in an increase in the connective tissue, were observed. It was concluded that a small dose of pre-operative radiation on eosinophilic granuloma in the parotid area made the tumor small and produced a capsule around the tumor. (author)

Operational risk and e-banking

Directory of Open Access Journals (Sweden)

Şerbu, R.

2010-12-01

Full Text Available Banking involves a variety of risks. Under Basel II, the main risks are the monitored credit risk, market risk and operational risk. Frequently, operational risks are underestimated, considering that they would not affect the optimal activity of a bank. However, past experience of some credit institutions have shown that operational risk is an important cause of financial losses in the banking sector. Operational risk is generated by a complex of factors that manifests primarily as a result of direct customer interaction with the credit institution. In this context, the provision of e-banking services reduces direct contact with bank customers and thus reduces potential losses arising from operational risk. In sum, we consider it necessary to be aware of the link between operational risk and e-banking services promoted by banks and of the importance of this connection especially in a financial environment affected by the financial crisis.

Family Connections: Building Connections among Home, School, and Community

Science.gov (United States)

Dikkers, Amy Garrett

2013-01-01

Recent research on parental involvement has explored connections between parental involvement in school and children's academic achievement. While many schools have active parent organizations and a base of parents who offer additional support, others struggle to make connections with their parents or community members. Even in places with active…

Mixed Connective Tissue Disease

Science.gov (United States)

Mixed connective tissue disease Overview Mixed connective tissue disease has signs and symptoms of a combination of disorders — primarily lupus, scleroderma and polymyositis. For this reason, mixed connective tissue disease ...

Visualizing neuronal network connectivity with connectivity pattern tables

Directory of Open Access Journals (Sweden)

Eilen Nordlie

2010-01-01

Full Text Available Complex ideas are best conveyed through well-designed illustrations. Up to now, computational neuroscientists have mostly relied on box-and-arrow diagrams of even complex neuronal networks, often using ad hoc notations with conflicting use of symbols from paper to paper. This significantly impedes the communication of ideas in neuronal network modeling. We present here Connectivity Pattern Tables (CPTs as a clutter-free visualization of connectivity in large neuronal networks containing two-dimensional populations of neurons. CPTs can be generated automatically from the same script code used to create the actual network in the NEST simulator. Through aggregation, CPTs can be viewed at different levels, providing either full detail or summary information. We also provide the open source ConnPlotter tool as a means to create connectivity pattern tables.

Optimal Protection Coordination for Microgrid under Different Operating Modes

Directory of Open Access Journals (Sweden)

Ming-Ta Yang

2013-01-01

Full Text Available Significant consequences result when a microgrid is connected to a distribution system. This study discusses the impacts of bolted three-phase faults and bolted single line-to-ground faults on the protection coordination of a distribution system connected by a microgrid which operates in utility-only mode or in grid-connected mode. The power system simulation software is used to build the test system. The linear programming method is applied to optimize the coordination of relays, and the relays coordination simulation software is used to verify if the coordination time intervals (CTIs of the primary/backup relay pairs are adequate. In addition, this study also proposes a relays protection coordination strategy when the microgrid operates in islanding mode during a utility power outage. Because conventional CO/LCO relays are not capable of detecting high impedance fault, intelligent electrical device (IED combined with wavelet transformer and neural network is proposed to accurately detect high impedance fault and identify the fault phase.

Connectivity: Performance Portable Algorithms for graph connectivity v. 0.1

Energy Technology Data Exchange (ETDEWEB)

2017-09-21

Graphs occur in several places in real world from road networks, social networks and scientific simulations. Connectivity is a graph analysis software to graph connectivity in modern architectures like multicore CPUs, Xeon Phi and GPUs.

Approximation theorems by Meyer-Koenig and Zeller type operators

International Nuclear Information System (INIS)

Ali Ozarslan, M.; Duman, Oktay

2009-01-01

This paper is mainly connected with the approximation properties of Meyer-Koenig and Zeller (MKZ) type operators. We first introduce a general sequence of MKZ operators based on q-integers and then obtain a Korovkin-type approximation theorem for these operators. We also compute their rates of convergence by means of modulus of continuity and the elements of Lipschitz class functionals. Furthermore, we give an rth order generalization of our operators in order to get some explicit approximation results.

Enhanced symmetries of gauge theory and resolving the spectrum of local operators

International Nuclear Information System (INIS)

Kimura, Yusuke; Ramgoolam, Sanjaye

2008-01-01

Enhanced global non-Abelian symmetries at zero coupling in Yang Mills theory play an important role in diagonalizing the two-point functions of multimatrix operators. Generalized Casimirs constructed from the iterated commutator action of these enhanced symmetries resolve all the multiplicity labels of the bases of matrix operators which diagonalize the two-point function. For the case of U(N) gauge theory with a single complex matrix in the adjoint of the gauge group we have a U(N) x4 global symmetry of the scaling operator at zero coupling. Different choices of commuting sets of Casimirs, for the case of a complex matrix, lead to the restricted Schur basis previously studied in connection with string excitations of giant gravitons and the Brauer basis studied in connection with brane-antibrane systems. More generally these remarks can be extended to the diagonalization for any global symmetry group G. Schur-Weyl duality plays a central role in connecting the enhanced symmetries and the diagonal bases.

Modelling and Simulation of VSC-HVDC Connection for Offshore Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro

2010-01-01

Several large offshore wind power plants (WPP) are planned in the seas around Europe. VSC-HVDC is a suitable means of integrating such large and distant offshore WPP which need long submarine cable transmission to the onshore grid. Recent trend is to use large wind turbine generators with full...... scale converters to achieve an optimal operation over a wide speed range. The offshore grid then becomes very much different from the conventional power system grid, in the sense that it is connected to power electronic converters only. A model of the wind power plant with VSC-HVDC connection...

Sturm-Liouville operators and applications

CERN Document Server

Marchenko, Vladimir A

2011-01-01

The spectral theory of Sturm-Liouville operators is a classical domain of analysis, comprising a wide variety of problems. Besides the basic results on the structure of the spectrum and the eigenfunction expansion of regular and singular Sturm-Liouville problems, it is in this domain that one-dimensional quantum scattering theory, inverse spectral problems, and the surprising connections of the theory with nonlinear evolution equations first become related. The main goal of this book is to show what can be achieved with the aid of transformation operators in spectral theory as well as in their

Operational gaming an international approach

CERN Document Server

Ståhl, Ingolf

1983-01-01

Operational Gaming: An International Approach focuses on various research on this method of systems analysis. The text points out the value of this method in decision making, planning, and in the implementation of policies. The book presents a survey that highlights the connection of experimental gaming, game theory, and operational gaming. The value of gaming as a balancing method in assessing multifaceted computer models, most notably about their assumptions on human behavior, is noted. The book also offers an overview of gaming in other countries, such as Bulgaria, Soviet Union, and Japan,

Enrichment of heavy water in thermal-diffusion columns connected in series

International Nuclear Information System (INIS)

Yeh, Ho-Ming; Chen, Liu Yi

2009-01-01

The separation equations for enrichment of heavy water from water isotope mixture by thermal diffusion in multiple columns connected in series, have been derived based on one column design developed in previous work. The improvement in separation is achievable by operating in a double-column device, instead of in a single-column device, with the same total column length. It is also found that further improvement in separation is obtainable if a triple-column device is employed, except for operating under small total column length and low flow rate.

Coordinated Voltage Control Scheme for VSC-HVDC Connected Wind Power Plants

DEFF Research Database (Denmark)

Guo, Yifei; Gao, Houlei; Wu, Qiuwei

2017-01-01

This paper proposes a coordinated voltage control scheme based on model predictive control (MPC) for voltage source converter‐based high voltage direct current (VSC‐HVDC) connected wind power plants (WPPs). In the proposed scheme, voltage regulation capabilities of VSC and WTGs are fully utilized...... and optimally coordinated. Two control modes, namely operation optimization mode and corrective mode, are designed to coordinate voltage control and economic operation of the system. In the first mode, the control objective includes the bus voltages, power losses and dynamic Var reserves of wind turbine...

Undifferentiated Connective Tissue Disease

Science.gov (United States)

... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... by Barbara Goldstein, MD (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

Total connectivity speeds research and support of field operations

International Nuclear Information System (INIS)

Himes, R.E.; Frost, K.I.; Henry, S.R.; Funkhouser, J.D.

1992-01-01

This paper reports that research and field support roles in the oilfield service industry have become increasingly complex in the last 15 years. Experimental apparatus are more dependent on the data-acquisition and processing capabilities of computers as the amount of data generated increases. Therefore, the need to network these computers for data transport has significantly increased. The type of network system selected depends on the goals to be achieved. Incorporation of existing equipment, communication between systems of different architectures, and future expandability are only a few of the necessary attributes. With these in mind, a computer network system was designed and is being implemented. The system combines local- and wide-area networks (LAN's or WAN's) of different protocols to acquire, process, and transport information worldwide. The result is faster development of new products and quicker response in support of field operations

Learning Gene Expression Through Modelling and Argumentation. A Case Study Exploring the Connections Between the Worlds of Knowledge

Science.gov (United States)

Puig, Blanca; Ageitos, Noa; Jiménez-Aleixandre, María Pilar

2017-12-01

There is emerging interest on the interactions between modelling and argumentation in specific contexts, such as genetics learning. It has been suggested that modelling might help students understand and argue on genetics. We propose modelling gene expression as a way to learn molecular genetics and diseases with a genetic component. The study is framed in Tiberghien's (2000) two worlds of knowledge, the world of "theories & models" and the world of "objects & events", adding a third component, the world of representations. We seek to examine how modelling and argumentation interact and connect the three worlds of knowledge while modelling gene expression. It is a case study of 10th graders learning about diseases with a genetic component. The research questions are as follows: (1) What argumentative and modelling operations do students enact in the process of modelling gene expression? Specifically, which operations allow connecting the three worlds of knowledge? (2) What are the interactions between modelling and argumentation in modelling gene expression? To what extent do these interactions help students connect the three worlds of knowledge and modelling gene expression? The argumentative operation of using evidence helps students to relate the three worlds of knowledge, enacted in all the connections. It seems to be a relationship among the number of interactions between modelling and argumentation, the connections between world of knowledge and students' capacity to develop a more sophisticated representation. Despite this is a case study, this approach of analysis reveals potentialities for a deeper understanding of learning genetics though scientific practices.

Voltage balancing strategies for serial connection of microbial fuel cells

Science.gov (United States)

Khaled, Firas; Ondel, Olivier; Allard, Bruno; Buret, François

2015-07-01

The microbial fuel cell (MFC) converts electrochemically organic matter into electricity by means of metabolisms of bacteria. The MFC power output is limited by low voltage and low current characteristics in the range of microwatts or milliwatts per litre. In order to produce a sufficient voltage level (>1.5 V) and sufficient power to supply real applications such as autonomous sensors, it is necessary to either scale-up one single unit or to connect multiple units together. Many topologies of connection are possible as the serial association to improve the output voltage, or the parallel connection to improve the output current or the series/parallel connection to step-up both voltage and current. The association of MFCs in series is a solution to increase the voltage to an acceptable value and to mutualize the unit's output power. The serial association of a large number of MFCs presents several issues. The first one is the hydraulic coupling among MFCs when they share the same substrate. The second one is the dispersion between generators that lead to a non-optimal stack efficiency because the maximum power point (MPP) operation of all MFCs is not permitted. Voltage balancing is a solution to compensate non-uniformities towards MPP. This paper presents solutions to improve the efficiency of a stack of serially connected MFCs through a voltage-balancing circuit. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014)", edited by Adel Razek

Analysis of turbine-grid interaction of grid-connected wind turbine using HHT

Science.gov (United States)

Chen, A.; Wu, W.; Miao, J.; Xie, D.

2018-05-01

This paper processes the output power of the grid-connected wind turbine with the denoising and extracting method based on Hilbert Huang transform (HHT) to discuss the turbine-grid interaction. At first, the detailed Empirical Mode Decomposition (EMD) and the Hilbert Transform (HT) are introduced. Then, on the premise of decomposing the output power of the grid-connected wind turbine into a series of Intrinsic Mode Functions (IMFs), energy ratio and power volatility are calculated to detect the unessential components. Meanwhile, combined with vibration function of turbine-grid interaction, data fitting of instantaneous amplitude and phase of each IMF is implemented to extract characteristic parameters of different interactions. Finally, utilizing measured data of actual parallel-operated wind turbines in China, this work accurately obtains the characteristic parameters of turbine-grid interaction of grid-connected wind turbine.

Duties of the Physikalisch-Technische Bundesanstalt (PTB) in connection with radioactive waste safeguarding and ultimate storage

International Nuclear Information System (INIS)

Roethemeyer, H.

1977-01-01

An outline of the history and duties of the Physikalisch-Technische Bundesanstalt (PTB) is to illustrate that the new duties of the PTB in connection with radioactive substance safeguarding and ultimate storage fit in very well with the range of duties of the PTB. The organisatory and technical accomplishment of these duties in cooperation with a building and operating company and with industry is explained. The department of the PTB for the 'safeguarding and ultimate storage of radioactive wastes' has an examining, appraising and licensing function in connection with construction, operation and shutdown of safety facilities. Methods for the safeguarding and ultimate storage of all the radioactive wastes in the Federal Republic of Germany are described. (HS) [de

Modal analysis of a grid-connected direct-drive permanent magnet synchronous generator wind turbine system

DEFF Research Database (Denmark)

Tan, Jin; Wang, Xiao Ru; Chen, Zhe

2013-01-01

In order to study the stability of a grid-connected direct-drive permanent magnet synchronous generator (PMSG) wind turbine systems, this paper presents the modal analysis of a PMSG wind turbine system. A PMSG model suitable for small signal stability analysis is presented. The modal properties...... of a grid-connected PMSG wind turbine system are studied. Then the comprehensive impacts of the shaft model, shaft parameters, operation points and lengths of the transmission line on the modal characteristic of the system are investigated by the eigenvalue analysis method. Meanwhile, the corresponding...... analysis. It offers a better understanding about the essence of the stability of grid-connected PMSG wind turbine system....

Long-term results of the corridor operation for atrial fibrillation

NARCIS (Netherlands)

van Hemel, N. M.; Defauw, J. J.; Kingma, J. H.; Jaarsma, W.; Vermeulen, F. E.; de Bakker, J. M.; Guiraudon, G. M.

1994-01-01

To investigate the long-term results of the corridor operation in the treatment of symptomatic atrial fibrillation refractory to drug treatment. The corridor operation is designed to isolate from the left and right atrium a conduit of atrial tissue connecting the sinus node area with the

Method to moor an offshore operating vessel

Energy Technology Data Exchange (ETDEWEB)

Flory, J.F.

1983-01-24

A vessel such as a storage vessel is permanently moored, by means such as a yoke pivoted on the forecastle of the vessel, to a mooring leg, e.g. a riser or anchor chain, which is attached to a base located on the ocean floor. Mounted on the vessel is tension exsisting means, for example, counterweights, springs, winches, or the like, operably connected with the mooring leg for applying tension thereto such as by lifting the yoke. The top of the mooring leg is connected to the end of the yoke through a mooring swivel and a gimbaled mooring table or a universal joint. A fluid swivel may be located above the mooring table or about a load-carrying shaft connected to the mooring leg. 8 drawings.

Alternative connection between territory of Poland and Far / Middle East countries for containers transport

Directory of Open Access Journals (Sweden)

Wiktor Żuchowski

2014-06-01

Full Text Available Background: The new cyclical service, available on the Polish market, related to the railway connection between Port of Koper and the terminal in Silesia, enables delivery of containers, skipping the Polish and German ports. To "the opening" of a direct connection with the Adriatic Sea arises dilemma that requires the identification of sustainability of the containers' transport to the Polish territories in economical and ecological terms. The key to this problem is a solution of the equation with several unknowns, which include the cost and time of transport, sea freight operator procedures, infrastructure constraints and the interests of local and regional communities. The analysis of the impact area of rail connection Koper - Slawkow was carried within Empiric project. The assumptions and results are described below. Material and methods: Based on the experience of the Slawkow-Koper link's operator and analysis of distances, cost, duration of containers transport, the research has been conducted, intended to estimate the area of influence of ports, located on the shores of the four seas surrounding area of Central Europe: Adriatic, Baltic, Black and North, with particular reference to the Port of Koper. The research used publicly available information, calculators, and disseminated investment plans. Results: Analysis of factors possible to calculate, especially the cost of containers' transport, by adopted assumptions, the study allowed to estimate the theoretical impact area of the Port of Koper. The area covers a large part of Poland, south from the line Szczecin-Brest. Besides aspect of cost impact area has been expanded due to different rail-gauge along the eastern Polish border. Also the environmental aspects indicate south direction of transport containers, as beneficial to the natural environment. As the factors reducing the development of the connections financial policies of the sea freight operators and infrastructure limitations of

Reliability Oriented Design Tool For the New Generation of Grid Connected PV-Inverters

DEFF Research Database (Denmark)

Sintamarean, Nicolae Cristian; Blaabjerg, Frede; Wang, Huai

2015-01-01

is achieved and is further used as an input to the lifetime model. The proposed reliability-oriented design tool is used to study the impact of mission profile (MP) variation and device degradation (aging) in the PV inverter lifetime. The obtained results indicate that the MP of the field where the PV...... inverter is operating has an important impact (up to 70%) on the converter lifetime expectation, and it should be considered in the design stage to better optimize the converter design margin. In order to have correct lifetime estimation, it is crucial to consider also the device degradation feedback (in......This paper introduces a reliability-oriented design tool for a new generation of grid-connected photovoltaic (PV) inverters. The proposed design tool consists of a real field mission profile (RFMP) model (for two operating regions: USA and Denmark), a PV panel model, a grid-connected PV inverter...

The text of the agreement of 22 July 1977 between Argentina and the Agency for the application of safeguards in connection with a co-operation agreement between Argentina and Canada

International Nuclear Information System (INIS)

1995-01-01

The Agreement between the Republic of Argentina, the Federative Republic of Brazil, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials and the International Atomic Energy Agency for the Application of Safeguards came into force on 4 March 1994. As a result of the coming into force of the aforesaid Agreement for Argentina, the application of safeguards under the Agreement of 22 July 1977 between Argentina and the IAEA for the application of safeguards in connection with a co-operation agreement between Argentina and Canada has been suspended

The Newcastle connection: A software subsystem for constructing distributed UNIX systems

International Nuclear Information System (INIS)

Randell, B.

1985-01-01

The Newcastle connection is a software subsystem that can be added to each of a set of physically interconnected UNIX or UNIX look-alike systems, so as to construct a distributed system which is functionally indistinguishable at both the user and the program level from a conventional single-processor UNIX system. The techniques used are applicable to a variety and multiplicity of both local and wide area networks, and enable all issues of inter-processor communication, network protocols, etc., to be hidden. A brief account is given of experience with such distributed systems, the first of which was constructed in 1982 using a set of PDP11s running UNIX Version 7, and connected by a Cambridge Ring - since this date the Connection has been used to construct distributed systems based on various other computers and versions of UNIX, both at Newcastle and elsewhere. The final sections compare our scheme to various precursor schemes and discuss its potential relevance to other operating systems. (orig.)

Characterization of high impedance connecting links for Bolometric detectors

Energy Technology Data Exchange (ETDEWEB)

Giachero, A. [INFN, Sezione di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Università di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy); Gotti, C. [INFN, Sezione di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Università di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy); Università di Firenze, Dipartimento di Elettronica e Telecomunicazioni, Via S. Marta 3, I-50139 Firenze (Italy); Maino, M. [INFN, Sezione di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Università di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy); Pessina, G., E-mail: pessina@mib.infn.it [INFN, Sezione di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Università di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy)

2013-08-01

High impedance connecting links and cables are tested at low frequency in terms of their parasitic impedance to ground and to neighboring connecting links. These parameters must be well characterized with detectors operated at low temperature, especially when the very front-end is at room temperature, which results in a long link. This is the case of the LUCIFER experiment, an array of crystals where every event of interest produces two signals, one composed of phonons, the other of photons. The parasitic impedance is usually considered to be the parallel combination of a resistance and a capacitance. We characterized both and found that from the static measurements the capacitance of the cable resulted much larger. On the basis of this result we optimized the measurement set-up and developed a model to account for this behavior.

Generalized connectivity of graphs

CERN Document Server

Li, Xueliang

2016-01-01

Noteworthy results, proof techniques, open problems and conjectures in generalized (edge-) connectivity are discussed in this book. Both theoretical and practical analyses for generalized (edge-) connectivity of graphs are provided. Topics covered in this book include: generalized (edge-) connectivity of graph classes, algorithms, computational complexity, sharp bounds, Nordhaus-Gaddum-type results, maximum generalized local connectivity, extremal problems, random graphs, multigraphs, relations with the Steiner tree packing problem and generalizations of connectivity. This book enables graduate students to understand and master a segment of graph theory and combinatorial optimization. Researchers in graph theory, combinatorics, combinatorial optimization, probability, computer science, discrete algorithms, complexity analysis, network design, and the information transferring models will find this book useful in their studies.

Identification of Synchronous Generator Electric Parameters Connected to the Distribution Grid

Directory of Open Access Journals (Sweden)

Frolov M. Yu.

2017-04-01

Full Text Available According to modern trends, the power grids with distributed generation will have an open system architecture. It means that active consumers, owners of distributed power units, including mobile units, must have free access to the grid, like when using internet, so it is necessary to have plug and play technologies. Thanks to them, the system will be able to identify the unit type and the unit parameters. Therefore, the main aim of research, described in the paper, was to develop and research a new method of electric parameters identification of synchronous generator. The main feature of the proposed method is that parameter identification is performed while the generator to the grid, so it fits in the technological process of operation of the machine and does not influence on the connection time of the machine. For the implementation of the method, it is not necessary to create dangerous operation modes for the machine or to have additional expensive equipment and it can be used for salient pole machines and round rotor machines. The parameter identification accuracy can be achieved by more accurate account of electromechanical transient process, and making of overdetermined system with many more numbers of equations. Parameter identification will be made with each generator connection to the grid. Comparing data obtained from each connection, the middle values can be find by numerical method, and thus, each subsequent identification will accurate the machine parameters.

Connectivity dynamics in typical development and its relationship to autistic traits and autism spectrum disorder.

Science.gov (United States)

Rashid, Barnaly; Blanken, Laura M E; Muetzel, Ryan L; Miller, Robyn; Damaraju, Eswar; Arbabshirani, Mohammad R; Erhardt, Erik B; Verhulst, Frank C; van der Lugt, Aad; Jaddoe, Vincent W V; Tiemeier, Henning; White, Tonya; Calhoun, Vince

2018-03-30

Recent advances in neuroimaging techniques have provided significant insights into developmental trajectories of human brain function. Characterizations of typical neurodevelopment provide a framework for understanding altered neurodevelopment, including differences in brain function related to developmental disorders and psychopathology. Historically, most functional connectivity studies of typical and atypical development operate under the assumption that connectivity remains static over time. We hypothesized that relaxing stationarity assumptions would reveal novel features of both typical brain development related to children on the autism spectrum. We employed a "chronnectomic" (recurring, time-varying patterns of connectivity) approach to evaluate transient states of connectivity using resting-state functional MRI in a population-based sample of 774 6- to 10-year-old children. Dynamic connectivity was evaluated using a sliding-window approach, and revealed four transient states. Internetwork connectivity increased with age in modularized dynamic states, illustrating an important pattern of connectivity in the developing brain. Furthermore, we demonstrated that higher levels of autistic traits and ASD diagnosis were associated with longer dwell times in a globally disconnected state. These results provide a roadmap to the chronnectomic organization of the developing brain and suggest that characteristics of functional brain connectivity are related to children on the autism spectrum. © 2018 Wiley Periodicals, Inc.

QPFT operator algebras and commutative exterior differential calculus

International Nuclear Information System (INIS)

Yur'ev, D.V.

1993-01-01

The reduction of the structure theory of the operator algebras of quantum projective (sl(2, C)-invariant) field theory (QPFT operator algebras) to a commutative exterior differential calculus by means of the operation of renormalization of a pointwise product of operator fields is described. In the first section, the author introduces the concept of the operator algebra of quantum field theory and describes the operation of the renormalization of a pointwise product of operator fields. The second section is devoted to a brief exposition of the fundamentals of the structure theory of QPT operator algebras. The third section is devoted to commutative exterior differential calculus. In the fourth section, the author establishes the connection between the renormalized pointwise product of operator fields in QPFT operator algebras and the commutative exterior differential calculus. 5 refs

Performance of a grid connected PV system used as active filter

International Nuclear Information System (INIS)

Calleja, Hugo; Jimenez, Humberto

2004-01-01

In this paper, the performance of a grid connected photovoltaic (PV) system used as an active filter is presented. Its main feature is the capability to compensate the reactive and harmonic currents drawn by nonlinear loads while simultaneously injecting into the grid the maximum power available from the cells. The system can also operate as a stand alone active filter. The system was connected to a 1 kW PV array and tested with the loads typically found in households: small motors, personal computers and electronic ballasts. The results show that the system can correct the power factor to values close to unity for all the cases tested, thereby improving the efficiency of the electric energy supply

Harmonic Interaction Analysis in Grid Connected Converter using Harmonic State Space (HSS) Modeling

DEFF Research Database (Denmark)

Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

2015-01-01

-model, are introduced to analyze these problems. However, it is found that Linear Time Invariant (LTI) base model analysis makes it difficult to analyze these phenomenon because of time varying system operation trajectories, varying output impedance seen by grid connected systems and neglected switching component......An increasing number of power electronics based Distributed Generation (DG) systems and loads generate coupled harmonic as well as non-characteristic harmonic with each other. Several methods like impedance based analysis, which is derived from conventional small signal- and average...... during the modeling process. This paper investigates grid connected converter by means of Harmonic State Space (HSS) small signal model, which is modeled from Linear Time varying Periodically (LTP) system. Further, a grid connected converter harmonic matrix is investigated to analyze the harmonic...

Alternative connections for the large MFTF-B solenoids

International Nuclear Information System (INIS)

Owen, E.W.; Shimer, D.W.; Wang, S.T.

1983-01-01

The MFTF-B central-cell solenoids are a set of twelve closely coupled, large superconducting magnets with similar but not exactly equal currents. Alternative methods of connecting them to their power supplies and dump resistors are investigated. The circuits are evaluated for operating conditions and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the current induced in coils that remain superconducting when one or more coils quench. The alternative connections include separate power supplies, combined power supplies, individual dump resistors, series dump resistors and combinations of these. A new circuit that contains coupling resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed in detail

Connected vehicle standards.

Science.gov (United States)

2016-01-01

Connected vehicles have the potential to transform the way Americans travel by : allowing cars, buses, trucks, trains, traffic signals, smart phones, and other devices to : communicate through a safe, interoperable wireless network. A connected vehic...

Effects of exercise and respiration on blood flow in total cavopulmonary connection

DEFF Research Database (Denmark)

Hjortdal, V E; Emmertsen, K; Stenbøg, E

2003-01-01

BACKGROUND: Little is known about blood flow and its relationship to respiration during exercise in patients with total cavopulmonary connection (TCPC). METHODS AND RESULTS: We studied 11 patients 12.4+/-4.6 years (mean+/-SD) of age 5.9+/-2.8 years (mean+/-SD) after TCPC operation. Real-time MRI...

Analysis of the network protection devices action connected with the Krsko NPP operation safety

International Nuclear Information System (INIS)

Omahen, P.; Struc, S.

1995-01-01

The example of failure that took place in Zagreb on 30 March, 1995, has been investigated in order to obtain appropriate answers to the unexpected electric power system (ESP) response and consecutive outage of the Krsko nuclear power plant (NPP). The analysis has been made of particular operating and stability conditions, related to the functioning of distance relays line protection. Using a consequent simulation model of the EPS (European interconnection) under specified fault condition, the research of EPS operation (relays action) and stability has been done. The appropriate simulation results have been compared to the available measured data which had been collected by the SOREL on-line data acquisition system. In the end, a practise proposal for measures to be taken with the target of achieving the foreseen and expected operation of the EPS equipment that effects operation of the Krsko NPP is given. (author)

Operating experience with snubbers

International Nuclear Information System (INIS)

Levin, H.; Cudlin, R.

1978-06-01

Recent operating experience with hydraulic and mechanical snubbers has indicated that there is a need to evaluate current practice in the industry associated with snubber qualification testing programs, design and analysis procedures, selection and specification criteria, and the preservice inspection and inservice surveillance programs. The report provides a summary of operational experiences that represent problems that are generic throughout the industry. Generic Task A-13 is part of the NRC Program for the Resolution of Generic Issues Related to Nuclear Power Plants described in NUREG-0410. The report is based upon a rather large amount of data that have become available in the past four years. These data have been evaluated by the Division of Operating Reactors to develop a data base for use in connection with several NRC activities including Category A, Technical Activity A-13 (Snubbers); the Standard Review Plan; future Regulatory Guides; ASME Code Provisions; and various technical specifications of operating nuclear power plants

Connectivity-oriented urban projects

NARCIS (Netherlands)

Philibert Petit, E.

2006-01-01

This thesis is about connections in the built environment, networked connections for the mobility of people at the smallest scale of the urban realm: the pedestrian scale. It deals with applications of the new science of networks as a tool for observation and assessment of connectivity in the urban

29 CFR Appendix H to Subpart R of... - Double Connections: Illustration of a Clipped End Connection and a Staggered Connection: Non...

Science.gov (United States)

2010-07-01

... Connection and a Staggered Connection: Non-Mandatory Guidelines for Complying With § 1926.756(c)(1) H Appendix H to Subpart R of Part 1926 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY... CONSTRUCTION Steel Erection Pt. 1926, Subpt. R, App. H Appendix H to Subpart R of Part 1926—Double Connections...

Prioritizing Urban Habitats for Connectivity Conservation: Integrating Centrality and Ecological Metrics.

Science.gov (United States)

Poodat, Fatemeh; Arrowsmith, Colin; Fraser, David; Gordon, Ascelin

2015-09-01

Connectivity among fragmented areas of habitat has long been acknowledged as important for the viability of biological conservation, especially within highly modified landscapes. Identifying important habitat patches in ecological connectivity is a priority for many conservation strategies, and the application of 'graph theory' has been shown to provide useful information on connectivity. Despite the large number of metrics for connectivity derived from graph theory, only a small number have been compared in terms of the importance they assign to nodes in a network. This paper presents a study that aims to define a new set of metrics and compares these with traditional graph-based metrics, used in the prioritization of habitat patches for ecological connectivity. The metrics measured consist of "topological" metrics, "ecological metrics," and "integrated metrics," Integrated metrics are a combination of topological and ecological metrics. Eight metrics were applied to the habitat network for the fat-tailed dunnart within Greater Melbourne, Australia. A non-directional network was developed in which nodes were linked to adjacent nodes. These links were then weighted by the effective distance between patches. By applying each of the eight metrics for the study network, nodes were ranked according to their contribution to the overall network connectivity. The structured comparison revealed the similarity and differences in the way the habitat for the fat-tailed dunnart was ranked based on different classes of metrics. Due to the differences in the way the metrics operate, a suitable metric should be chosen that best meets the objectives established by the decision maker.

On the connection between quantum fields and von Neumann algebras of local operators

International Nuclear Information System (INIS)

Driessler, W.; Summers, S.J.; Wichmann, E.H.

1986-01-01

The relationship between a standard local quantum field and a net of local von Neumann algebras is discussed. Two natural possibilities for such an association are identified, and conditions for these to obtain are found. It is shown that the local net can naturally be so chosen that it satisfies the Special Condition of Duality. The notion of an intrinsically local field operator is introduced, and it is shown that such an operator defines a local net with which the field is locally associated. A regularity condition on the field is formulated, and it is shown that if this condition holds, then there exists a unique local net with which the field is locally associated if and only if the field algebra contains at least one intrinsically local operator. Conditions under which a field and other fields in its Borchers class are associated with the same local net are found, in terms of the regularity condition mentioned. (orig.)

Sabotage Operations of the Prewar Anti-Facist League - Poland

National Research Council Canada - National Science Library

Szubanski, Rajmund

1960-01-01

The following article is a translation and deals with sabotage operations of the prewar Anti-Fascist League that was connected to the Communist Party, the International Seaman's and Dockers' Unions...

Impact of connected vehicles on mitigating secondary crash risk

Directory of Open Access Journals (Sweden)

Hong Yang

2017-09-01

Full Text Available Reducing the risk of secondary crashes is a key goal for effective traffic incident management. However, only few countermeasures have been established in practices to achieve the goal. This is mainly due to the stochastic nature of both primary and secondary crashes. Given the emerging connected vehicle (CV technologies, it is highly likely that CVs will soon be able to communicate with each other through the ad-hoc wireless vehicular network. Information sharing among vehicles is deemed to change traffic operations and allow motorists for more proactive actions. Motorists who receive safety messages can be motivated to approach queues and incident sites with more caution. As a result of the improved situational awareness, the risk of secondary crashes is expected to be reduced. To examine whether this expectation is achievable or not, this study aims to assess the impact of connectivity on the risk of secondary crashes. A simulation-based modeling framework that enables vehicle-to-vehicle communication module was developed. Since crashes cannot be directly simulated in micro-simulation, the use of surrogate safety measures was proposed to capture vehicular conflicts as a proxy for secondary crash risk upstream of a primary crash site. An experimental study was conducted based on the developed simulation modeling framework. The results show that the use of connected vehicles can be a viable way to reduce the risk of secondary crashes. Their impact is expected to change with an increasing market penetration of connected vehicles.

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...

Power Quality of Grid-Connected Wind Turbines with DFIG and Their Interaction with the Grid

DEFF Research Database (Denmark)

Sun, Tao

quality issues of grid-connected wind turbines and the interaction between wind turbines and the grid. The specific goal of the research has been to investigate flicker emission and mitigation of grid-connected wind turbines with doubly fed induction generators (DFIG) during continuous operation...... measures are proposed to mitigate the flicker levels produced by grid-connected wind turbines with DFIG, respectively by wind turbine output reactive power control and using STATCOM. Simulation results demonstrate that these two measures are effective for flicker mitigation regardless of mean wind speed....... To evaluate the flicker levels produced by grid-connected wind turbines with DFIG, a flickermeter model is developed according to the IEC standard IEC 61000-4-15, which simulates the response of the lamp-eye-brain chain and provides on-line statistical analysis ofthe flicker signal and the final results...

A connection between the Uncertainty Principles on the real line and on the circle

OpenAIRE

Andersen, Nils Byrial

2013-01-01

The purpose of this short note is to exhibit a new connection between the Heisenberg Uncertainty Principle on the line and the Breitenberger Uncertainty Principle on the circle, by considering the commutator of the multiplication and difference operators on Bernstein functions

Operational controlling - a tool of translating strategy into action

Directory of Open Access Journals (Sweden)

2011-03-01

Full Text Available . Enterprises have a lot of problems with realization their strategic aims in the fast changing and competitive business arena from many years. Effective execution of strategic plan needs its translating into action, task results and indicators of everyday activities. The success on the market is attainable by communicating strategic and operating goals on the each level of organizational structure and their connecting with budget of units or employee motivation. The scorecards balancing in finance, customer, process and development perspectives is very useful for pointing - what do we control with? or - what do we have to achieve? But doesn't answer to question about ways of enterprise managing. Main aim of the article is proving that operational controlling system is a essential tool for translating strategy into action. The Balanced Scorecard methodology should to take into consideration system and process connection of enterprise with procurement, co-operation or distribution supply chain also.

Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results.

Science.gov (United States)

Humada, Ali M; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M; Ahmed, Mushtaq N

2016-01-01

A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions.

The Study on Hybrid Multi-Infeed HVDC System Connecting with Offshore Wind Farm

DEFF Research Database (Denmark)

Liu, Yan

furnish the VSC-HVDC connected wind farm with a fast and reliable LVRT ability. The voltage fluctuation caused by the intermittent wind power is another important challenge to the system stability. As in the case of the LCC-HVDC links, their stable operations are highly dependent on the AC side voltage...... with the short electrical distance. And consequently, a so-called Multi-Infeed Direct Current (MIDC) transmission system is formed. On the other hand, as the fast growing of wind power in electrical grids, the Voltage Source Converter based HVDC (VSC-HVDC) links have becoming a favorable choice for connecting...

Defect networks and supersymmetric loop operators

Energy Technology Data Exchange (ETDEWEB)

Bullimore, Mathew [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada)

2015-02-10

We consider topological defect networks with junctions in A{sub N−1} Toda CFT and the connection to supersymmetric loop operators in N=2 theories of class S on a four-sphere. Correlation functions in the presence of topological defect networks are computed by exploiting the monodromy of conformal blocks, generalising the notion of a Verlinde operator. Concentrating on a class of topological defects in A{sub 2} Toda theory, we find that the Verlinde operators generate an algebra whose structure is determined by a set of generalised skein relations that encode the representation theory of a quantum group. In the second half of the paper, we explore the dictionary between topological defect networks and supersymmetric loop operators in the N=2{sup ∗} theory by comparing to exact localisation computations. In this context, the the generalised skein relations are related to the operator product expansion of loop operators.

Using graph approach for managing connectivity in integrative landscape modelling

Science.gov (United States)

Rabotin, Michael; Fabre, Jean-Christophe; Libres, Aline; Lagacherie, Philippe; Crevoisier, David; Moussa, Roger

2013-04-01

In cultivated landscapes, a lot of landscape elements such as field boundaries, ditches or banks strongly impact water flows, mass and energy fluxes. At the watershed scale, these impacts are strongly conditionned by the connectivity of these landscape elements. An accurate representation of these elements and of their complex spatial arrangements is therefore of great importance for modelling and predicting these impacts.We developped in the framework of the OpenFLUID platform (Software Environment for Modelling Fluxes in Landscapes) a digital landscape representation that takes into account the spatial variabilities and connectivities of diverse landscape elements through the application of the graph theory concepts. The proposed landscape representation consider spatial units connected together to represent the flux exchanges or any other information exchanges. Each spatial unit of the landscape is represented as a node of a graph and relations between units as graph connections. The connections are of two types - parent-child connection and up/downstream connection - which allows OpenFLUID to handle hierarchical graphs. Connections can also carry informations and graph evolution during simulation is possible (connections or elements modifications). This graph approach allows a better genericity on landscape representation, a management of complex connections and facilitate development of new landscape representation algorithms. Graph management is fully operational in OpenFLUID for developers or modelers ; and several graph tools are available such as graph traversal algorithms or graph displays. Graph representation can be managed i) manually by the user (for example in simple catchments) through XML-based files in easily editable and readable format or ii) by using methods of the OpenFLUID-landr library which is an OpenFLUID library relying on common open-source spatial libraries (ogr vector, geos topologic vector and gdal raster libraries). Open

Anesthetic implications of total anomalous systemic venous connection to left atrium with left isomerism

Directory of Open Access Journals (Sweden)

Parimala Prasanna Simha

2012-01-01

Full Text Available Total anomalous systemic venous connection (TASVC to the left atrium (LA is a rare congenital anomaly. An 11-year-old girl presented with complaints of palpitations and cyanosis. TASVC with left isomerism and noncompaction of LV was diagnosed after contrast echocardiogram and computed tomography angiogram. The knowledge of anatomy and pathophysiology is essential for the successful management of these cases. Anesthetic concerns in this case were polycythemia, paradoxical embolism and rhythm abnormalities. The patient was successfully operated by rerouting the systemic venous connection to the right atrium.

Connective Tissue Disorders

Science.gov (United States)

... of connective tissue. Over 200 disorders that impact connective tissue. There are different types: Genetic disorders, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta Autoimmune disorders, such as lupus and scleroderma Cancers, like some types of soft tissue sarcoma Each ...

Disturbed Interhemispheric Functional Connectivity Rather than Structural Connectivity in Irritable Bowel Syndrome

Directory of Open Access Journals (Sweden)

Rongfeng Qi

2016-12-01

Full Text Available Neuroimaging studies have demonstrated that irritable bowel syndrome (IBS—a relapsing functional bowel disorder—presents with disrupted brain connections. However, little is known about the alterations of interhemispheric functional connectivity and underlying structural connectivity in IBS. This study combined resting-state functional magnetic resonance imaging (MRI and diffusion tensor imaging (DTI to investigate changes in interhemispheric coordination in IBS patients. Resting-state functional and structural magnetic resonance images were acquired from 65 IBS patients and 67 healthy controls (matched for age, sex and educational level. Interhemispheric voxel-mirrored homotopic connectivity (VMHC was calculated and compared between groups. Homotopic regions showing abnormal VMHC in patients were targeted as regions of interest for analysis of DTI tractography. The fractional anisotropy, fiber number, and fiber length were compared between groups. Statistical analysis was also performed by including anxiety and depression as covariates to evaluate their effect. A Pearson correlation analysis between abnormal interhemispheric connectivity and clinical indices of IBS patients was performed. Compared to healthy controls, IBS patients had higher interhemispheric functional connectivity between bilateral thalami, cuneus, posterior cingulate cortices, lingual gyri and inferior occipital/cerebellum lobes, as well as lower interhemispheric functional connectivity between bilateral ventral anterior cingulate cortices (vACC and inferior parietal lobules (IPL. The inclusion of anxiety and depression as covariates abolished VMHC difference in vACC. Microstructural features of white matter tracts connecting functionally abnormal regions did not reveal any differences between the groups. VMHC values in vACC negatively correlated with the quality of life scores of patients. In conclusion, this study provides preliminary evidence of the disrupted

Connecting to Everyday Practices

DEFF Research Database (Denmark)

Iversen, Ole Sejer; Smith, Rachel Charlotte

2012-01-01

construction and reproduction of cultural heritage creating novel connections between self and others and between past, present and future. We present experiences from a current research project, the Digital Natives exhibition, in which social media was designed as an integral part of the exhibition to connect...... focusing on the connections between audiences practices and the museum exhibition....

Optimal Control of Connected and Automated Vehicles at Roundabouts

Energy Technology Data Exchange (ETDEWEB)

Zhao, Liuhui [University of Delaware; Malikopoulos, Andreas [ORNL; Rios-Torres, Jackeline [ORNL

2018-01-01

Connectivity and automation in vehicles provide the most intriguing opportunity for enabling users to better monitor transportation network conditions and make better operating decisions to improve safety and reduce pollution, energy consumption, and travel delays. This study investigates the implications of optimally coordinating vehicles that are wirelessly connected to each other and to an infrastructure in roundabouts to achieve a smooth traffic flow without stop-and-go driving. We apply an optimization framework and an analytical solution that allows optimal coordination of vehicles for merging in such traffic scenario. The effectiveness of the efficiency of the proposed approach is validated through simulation and it is shown that coordination of vehicles can reduce total travel time by 3~49% and fuel consumption by 2~27% with respect to different traffic levels. In addition, network throughput is improved by up to 25% due to elimination of stop-and-go driving behavior.

Removal of suspended solids and turbidity from marble processing wastewaters by electrocoagulation: Comparison of electrode materials and electrode connection systems

Energy Technology Data Exchange (ETDEWEB)

Solak, Murat [Duezce University, Kaynasli Vocational School, Environmental Protection and Control Department, 81900 Duezce (Turkey); Kilic, Mehmet, E-mail: kavi@mmf.sdu.edu.tr [Sueleyman Demirel University, Engineering and Architecture Faculty, Environmental Engineering Department, 32260 Isparta (Turkey); Hueseyin, Yazici; Sencan, Aziz [Sueleyman Demirel University, Engineering and Architecture Faculty, Environmental Engineering Department, 32260 Isparta (Turkey)

2009-12-15

In this study, removal of suspended solids (SS) and turbidity from marble processing wastewaters by electrocoagulation (EC) process were investigated by using aluminium (Al) and iron (Fe) electrodes which were run in serial and parallel connection systems. To remove these pollutants from the marble processing wastewater, an EC reactor including monopolar electrodes (Al/Fe) in parallel and serial connection system, was utilized. Optimization of differential operation parameters such as pH, current density, and electrolysis time on SS and turbidity removal were determined in this way. EC process with monopolar Al electrodes in parallel and serial connections carried out at the optimum conditions where the pH value was 9, current density was approximately 15 A/m{sup 2}, and electrolysis time was 2 min resulted in 100% SS removal. Removal efficiencies of EC process for SS with monopolar Fe electrodes in parallel and serial connection were found to be 99.86% and 99.94%, respectively. Optimum parameters for monopolar Fe electrodes in both of the connection types were found to be for pH value as 8, for electrolysis time as 2 min. The optimum current density value for Fe electrodes used in serial and parallel connections was also obtained at 10 and 20 A/m{sup 2}, respectively. Based on the results obtained, it was found that EC process running with each type of the electrodes and the connections was highly effective for the removal of SS and turbidity from marble processing wastewaters, and that operating costs with monopolar Al electrodes in parallel connection were the cheapest than that of the serial connection and all the configurations for Fe electrode.

Removal of suspended solids and turbidity from marble processing wastewaters by electrocoagulation: Comparison of electrode materials and electrode connection systems

International Nuclear Information System (INIS)

Solak, Murat; Kilic, Mehmet; Hueseyin, Yazici; Sencan, Aziz

2009-01-01

In this study, removal of suspended solids (SS) and turbidity from marble processing wastewaters by electrocoagulation (EC) process were investigated by using aluminium (Al) and iron (Fe) electrodes which were run in serial and parallel connection systems. To remove these pollutants from the marble processing wastewater, an EC reactor including monopolar electrodes (Al/Fe) in parallel and serial connection system, was utilized. Optimization of differential operation parameters such as pH, current density, and electrolysis time on SS and turbidity removal were determined in this way. EC process with monopolar Al electrodes in parallel and serial connections carried out at the optimum conditions where the pH value was 9, current density was approximately 15 A/m 2 , and electrolysis time was 2 min resulted in 100% SS removal. Removal efficiencies of EC process for SS with monopolar Fe electrodes in parallel and serial connection were found to be 99.86% and 99.94%, respectively. Optimum parameters for monopolar Fe electrodes in both of the connection types were found to be for pH value as 8, for electrolysis time as 2 min. The optimum current density value for Fe electrodes used in serial and parallel connections was also obtained at 10 and 20 A/m 2 , respectively. Based on the results obtained, it was found that EC process running with each type of the electrodes and the connections was highly effective for the removal of SS and turbidity from marble processing wastewaters, and that operating costs with monopolar Al electrodes in parallel connection were the cheapest than that of the serial connection and all the configurations for Fe electrode.

Removal of suspended solids and turbidity from marble processing wastewaters by electrocoagulation: comparison of electrode materials and electrode connection systems.

Science.gov (United States)

Solak, Murat; Kiliç, Mehmet; Hüseyin, Yazici; Sencan, Aziz

2009-12-15

In this study, removal of suspended solids (SS) and turbidity from marble processing wastewaters by electrocoagulation (EC) process were investigated by using aluminium (Al) and iron (Fe) electrodes which were run in serial and parallel connection systems. To remove these pollutants from the marble processing wastewater, an EC reactor including monopolar electrodes (Al/Fe) in parallel and serial connection system, was utilized. Optimization of differential operation parameters such as pH, current density, and electrolysis time on SS and turbidity removal were determined in this way. EC process with monopolar Al electrodes in parallel and serial connections carried out at the optimum conditions where the pH value was 9, current density was approximately 15 A/m(2), and electrolysis time was 2 min resulted in 100% SS removal. Removal efficiencies of EC process for SS with monopolar Fe electrodes in parallel and serial connection were found to be 99.86% and 99.94%, respectively. Optimum parameters for monopolar Fe electrodes in both of the connection types were found to be for pH value as 8, for electrolysis time as 2 min. The optimum current density value for Fe electrodes used in serial and parallel connections was also obtained at 10 and 20 A/m(2), respectively. Based on the results obtained, it was found that EC process running with each type of the electrodes and the connections was highly effective for the removal of SS and turbidity from marble processing wastewaters, and that operating costs with monopolar Al electrodes in parallel connection were the cheapest than that of the serial connection and all the configurations for Fe electrode.

Hysteresis current control technique of VSI for compensation of grid-connected unbalanced loads

DEFF Research Database (Denmark)

Pouresmaeil, Edris; Akorede, Mudathir Funsho; Montesinos-Miracle, Daniel

2014-01-01

interconnection issues that usually arise as DG units connect to the electric grid. The proposed strategy, implemented in Matlab/Simulink environment in different operating scenarios, provides compensation for active, reactive, unbalanced, and harmonic current components of grid-connected nonlinear unbalanced...... resources as they connect to the exiting power grid could provoke many power quality problems on the grid side. For this reason, due considerations must be given to power generation and safe running before DG units is actually integrated into the power grid. The main aim of this paper is to address the grid...... loads. The simulation results obtained in this study demonstrate the level of accuracy of the proposed technique, which ensure a balance in the overall grid phase currents, injection of maximum available power from DG resources to the grid, improvement of the utility grid power factor, and a reduction...

Cluster size statistic and cluster mass statistic: two novel methods for identifying changes in functional connectivity between groups or conditions.

Science.gov (United States)

Ing, Alex; Schwarzbauer, Christian

2014-01-01

Functional connectivity has become an increasingly important area of research in recent years. At a typical spatial resolution, approximately 300 million connections link each voxel in the brain with every other. This pattern of connectivity is known as the functional connectome. Connectivity is often compared between experimental groups and conditions. Standard methods used to control the type 1 error rate are likely to be insensitive when comparisons are carried out across the whole connectome, due to the huge number of statistical tests involved. To address this problem, two new cluster based methods--the cluster size statistic (CSS) and cluster mass statistic (CMS)--are introduced to control the family wise error rate across all connectivity values. These methods operate within a statistical framework similar to the cluster based methods used in conventional task based fMRI. Both methods are data driven, permutation based and require minimal statistical assumptions. Here, the performance of each procedure is evaluated in a receiver operator characteristic (ROC) analysis, utilising a simulated dataset. The relative sensitivity of each method is also tested on real data: BOLD (blood oxygen level dependent) fMRI scans were carried out on twelve subjects under normal conditions and during the hypercapnic state (induced through the inhalation of 6% CO2 in 21% O2 and 73%N2). Both CSS and CMS detected significant changes in connectivity between normal and hypercapnic states. A family wise error correction carried out at the individual connection level exhibited no significant changes in connectivity.

Making the connection: The B.C. Hydro electric system and how it is operated

International Nuclear Information System (INIS)

1993-01-01

British Columbia Hydro supplies electric energy to 93% of the province's population through an integrated electric system. Of the electricity supplied, 95% is generated at 29 hydroelectric plants, with the remainder coming from thermal plants burning fossil fuels. BC Hydro's high voltage transmission and distribution network consists of 17,600 km of lines 60 kV and above and 51,400 km of lines below 60 kV. A description of system operations begins with the principles of hydroelectric generation, with a brief note on thermal generation for peaking or short-term energy production. Non-power operations measures designed to minimize environmental impacts and enhance social benefits are also outlined along with electricity trade with other provinces and the USA. Planning of long- and short-term system operations is also reviewed. An analysis of system components is presented for the Peace, Columbia, Lower Mainland/Coastal/Fraser, and Vancouver Island regions. Finally, information is given on the 29 hydroelectric and 3 thermal plants, including drainage basin, reservoir description and map, inflow, capacity, turbine type, storage, operating constraints, and average energy capability. 51 figs

The operating reliability of the reactor coolant pump

International Nuclear Information System (INIS)

Grancy, W.

1996-01-01

There is a strong tendency among operating companies and manufacturers of nuclear power stations to further increase safety and operating availability of the plant and of its components. This applies also and particularly to reactor coolant pumps for the primary circuit of nuclear power stations of the type PWR. For 3 decades, ANDRITZ has developed and built such pumps and has attached great importance to the design of the complete pump rotor and of its essential surrounding elements, such as bearing and shaft seal. Apart from questions connected with design functioning of the pump there is one question of top priority: the operating reliability of the reactor coolant pump. The pump rotor (together with the rotor of the drive motor) is the only component within the primary system that permanently rotates at high speed during operation of the reactor plant. Many questions concerning design and configuration of such components cannot be answered purely theoretically, or they can only be answered partly. Therefore comprehensive development work and testing was necessary to increase the operating reliability of the pump rotor itself and of its surrounding elements. This contribution describes the current status of development and, as a focal point, discusses shaft sealing solutions elaborated so far. In this connection also a sealing system will be presented which aims for the first time at using a two-stage mechanical seal in reactor coolant pumps

Modeling Structural Brain Connectivity

DEFF Research Database (Denmark)

Ambrosen, Karen Marie Sandø

The human brain consists of a gigantic complex network of interconnected neurons. Together all these connections determine who we are, how we react and how we interpret the world. Knowledge about how the brain is connected can further our understanding of the brain’s structural organization, help...... improve diagnosis, and potentially allow better treatment of a wide range of neurological disorders. Tractography based on diffusion magnetic resonance imaging is a unique tool to estimate this “structural connectivity” of the brain non-invasively and in vivo. During the last decade, brain connectivity...... has increasingly been analyzed using graph theoretic measures adopted from network science and this characterization of the brain’s structural connectivity has been shown to be useful for the classification of populations, such as healthy and diseased subjects. The structural connectivity of the brain...

Review on Cold-Formed Steel Connections

Science.gov (United States)

Tan, Cher Siang; Mohammad, Shahrin; Md Tahir, Mahmood; Shek, Poi Ngian

2014-01-01

The concept of cold-formed light steel framing construction has been widespread after understanding its structural characteristics with massive research works over the years. Connection serves as one of the important elements for light steel framing in order to achieve its structural stability. Compared to hot-rolled steel sections, cold-formed steel connections perform dissimilarity due to the thin-walled behaviour. This paper aims to review current researches on cold-formed steel connections, particularly for screw connections, storage rack connections, welded connections, and bolted connections. The performance of these connections in the design of cold-formed steel structures is discussed. PMID:24688448

Operator Support System for Pressurized Water Reactor

International Nuclear Information System (INIS)

Wei Renjie; Shen Shifei

1996-01-01

Operator Support System for Pressurized Water Reactor (OSSPWR) has been developed under the sponsorship of IAEA from August 1994. The project is being carried out by the Department of Engineering Physics, Tsinghua University, Beijing, China. The Design concepts of the operator support functions have been established. The prototype systems of OSSPWR has been developed as well. The primary goal of the project is to create an advanced operator support system by applying new technologies such as artificial intelligence (AI) techniques, advanced communication technologies, etc. Recently, the advanced man-machine interface for nuclear power plant operators has been developed. It is connected to the modern computer systems and utilizes new high performance graphic displays. (author). 6 refs, 4 figs

Discrete Green’s function diakoptics for stable FDTD interaction between multiply-connected domains

NARCIS (Netherlands)

Hon, de B.P.; Arnold, J.M.; Graglia, R.D.

2007-01-01

We have developed FDTD boundary conditions based on discrete Green's function diakoptics for arbitrary multiply-connected 2D domains. The associated Z-domain boundary operator is symmetric, with an imaginary part that can be proved to be positive semi-definite on the upper half of the unit circle in

Dynamic brain connectivity is a better predictor of PTSD than static connectivity.

Science.gov (United States)

Jin, Changfeng; Jia, Hao; Lanka, Pradyumna; Rangaprakash, D; Li, Lingjiang; Liu, Tianming; Hu, Xiaoping; Deshpande, Gopikrishna

2017-09-01

Using resting-state functional magnetic resonance imaging, we test the hypothesis that subjects with post-traumatic stress disorder (PTSD) are characterized by reduced temporal variability of brain connectivity compared to matched healthy controls. Specifically, we test whether PTSD is characterized by elevated static connectivity, coupled with decreased temporal variability of those connections, with the latter providing greater sensitivity toward the pathology than the former. Static functional connectivity (FC; nondirectional zero-lag correlation) and static effective connectivity (EC; directional time-lagged relationships) were obtained over the entire brain using conventional models. Dynamic FC and dynamic EC were estimated by letting the conventional models to vary as a function of time. Statistical separation and discriminability of these metrics between the groups and their ability to accurately predict the diagnostic label of a novel subject were ascertained using separate support vector machine classifiers. Our findings support our hypothesis that PTSD subjects have stronger static connectivity, but reduced temporal variability of connectivity. Further, machine learning classification accuracy obtained with dynamic FC and dynamic EC was significantly higher than that obtained with static FC and static EC, respectively. Furthermore, results also indicate that the ease with which brain regions engage or disengage with other regions may be more sensitive to underlying pathology than the strength with which they are engaged. Future studies must examine whether this is true only in the case of PTSD or is a general organizing principle in the human brain. Hum Brain Mapp 38:4479-4496, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Optimal Control of Micro Grid Operation Mode Seamless Switching Based on Radau Allocation Method

Science.gov (United States)

Chen, Xiaomin; Wang, Gang

2017-05-01

The seamless switching process of micro grid operation mode directly affects the safety and stability of its operation. According to the switching process from island mode to grid-connected mode of micro grid, we establish a dynamic optimization model based on two grid-connected inverters. We use Radau allocation method to discretize the model, and use Newton iteration method to obtain the optimal solution. Finally, we implement the optimization mode in MATLAB and get the optimal control trajectory of the inverters.

Single-Phase Microgrid with Seamless Transition Capabilities between Modes of Operation

DEFF Research Database (Denmark)

Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

2015-01-01

with the secondary control loops that are used to synchronize the microgrid as a single unit to the grid. Simulation results are given that show the seamless transitions between the two modes without any disconnection times for the CC-VSIs and VC-VSIs connected to the microgrid.......Microgrids are an effective way to increase the penetration of DG into the grid. They are capable of operating either in grid-connected or in islanded mode thereby increasing the supply reliability for the end user. This paper focuses on achieving seamless transitions from islanded to grid-connected...

SMES application for frequency control during islanded microgrid operation

Science.gov (United States)

Kim, A.-Rong; Kim, Gyeong-Hun; Heo, Serim; Park, Minwon; Yu, In-Keun; Kim, Hak-Man

2013-01-01

This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail.

Connected and disconnected quark contributions to hadron spin

International Nuclear Information System (INIS)

Chambers, A.J.

2014-12-01

By introducing an external spin operator to the fermion action, the quark spin fractions of hadrons are determined from the linear response of the hadron energies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour symmetric point, we find that the connected quark spin fractions are universally in the range 55-70% for vector mesons and octet and decuplet baryons. There is an indication that the amount of spin suppression is quite sensitive to the strength of SU(3) breaking. We also present first preliminary results applying the FH technique to calculations of quark-line disconnected contributions to hadronic matrix elements of axial and tensor operators. At the SU(3)-flavour symmetric point we find a small negative contribution to the nucleon spin from disconnected quark diagrams, while the corresponding tensor matrix elements are consistent with zero.

On the Connectivity of Wireless Network Systems and an Application in Teacher-Student Interactive Platforms

Directory of Open Access Journals (Sweden)

Xun Ge

2014-01-01

Full Text Available A wireless network system is a pair (U;B, where B is a family of some base stations and U is a set of their users. To investigate the connectivity of wireless network systems, this paper takes covering approximation spaces as mathematical models of wireless network systems. With the help of covering approximation operators, this paper characterizes the connectivity of covering approximation spaces by their definable subsets. Furthermore, it is obtained that a wireless network system is connected if and only if the relevant covering approximation space has no nonempty definable proper subset. As an application of this result, the connectivity of a teacher-student interactive platform is discussed, which is established in the School of Mathematical Sciences of Soochow University. This application further demonstrates the usefulness of rough set theory in pedagogy and makes it possible to research education by logical methods and mathematical methods.

Interdependence of PRECIS Role Operators: A Quantitative Analysis of Their Associations.

Science.gov (United States)

Mahapatra, Manoranjan; Biswas, Subal Chandra

1986-01-01

Analyzes associations among different role operators quantitatively by taking input strings from 200 abstracts, each related to subject fields of taxation, genetic psychology, and Shakespearean drama, and subjecting them to the Chi-square test. Significant associations by other differencing operators and connectives are discussed. A schema of role…

Connectivity in river deltas

Science.gov (United States)

Passalacqua, P.; Hiatt, M. R.; Sendrowski, A.

2016-12-01

Deltas host approximately half a billion people and are rich in ecosystem diversity and economic resources. However, human-induced activities and climatic shifts are significantly impacting deltas around the world; anthropogenic disturbance, natural subsidence, and eustatic sea-level rise are major causes of threat to deltas and in many cases have compromised their safety and sustainability, putting at risk the people that live on them. In this presentation, I will introduce a framework called Delta Connectome for studying connectivity in river deltas based on different representations of a delta as a network. Here connectivity indicates both physical connectivity (how different portions of the system interact with each other) as well as conceptual (pathways of process coupling). I will explore several network representations and show how quantifying connectivity can advance our understanding of system functioning and can be used to inform coastal management and restoration. From connectivity considerations, the delta emerges as a leaky network that evolves over time and is characterized by continuous exchanges of fluxes of matter, energy, and information. I will discuss the implications of connectivity on delta functioning, land growth, and potential for nutrient removal.

Very true operators on MTL-algebras

Directory of Open Access Journals (Sweden)

Wang Jun Tao

2016-01-01

Full Text Available The main goal of this paper is to investigate very true MTL-algebras and prove the completeness of the very true MTL-logic. In this paper, the concept of very true operators on MTL-algebras is introduced and some related properties are investigated. Also, conditions for an MTL-algebra to be an MV-algebra and a Gödel algebra are given via this operator. Moreover, very true filters on very true MTL-algebras are studied. In particular, subdirectly irreducible very true MTL-algebras are characterized and an analogous of representation theorem for very true MTL-algebras is proved. Then, the left and right stabilizers of very true MTL-algebras are introduced and some related properties are given. As applications of stabilizer of very true MTL-algebras, we produce a basis for a topology on very true MTL-algebras and show that the generated topology by this basis is Baire, connected, locally connected and separable. Finally, the corresponding logic very true MTL-logic is constructed and the soundness and completeness of this logic are proved based on very true MTL-algebras.

Research on Connection and Function Reliability of the Oil＆Gas Pipeline System

Directory of Open Access Journals (Sweden)

Xu Bo

2017-01-01

Full Text Available Pipeline transportation is the optimal way for energy delivery in terms of safety, efficiency and environmental protection. Because of the complexity of pipeline external system including geological hazards, social and cultural influence, it is a great challenge to operate the pipeline safely and reliable. Therefore, the pipeline reliability becomes an important issue. Based on the classical reliability theory, the analysis of pipeline system is carried out, then the reliability model of the pipeline system is built, and the calculation is addressed thereafter. Further the connection and function reliability model is applied to a practical active pipeline system, with the use of the proposed methodology of the pipeline system; the connection reliability and function reliability are obtained. This paper firstly presented to considerate the connection and function reliability separately and obtain significant contribution to establish the mathematical reliability model of pipeline system, hence provide fundamental groundwork for the pipeline reliability research in the future.

Big data's implications for transportation operations : an exploration.

Science.gov (United States)

The purpose of this white paper is to expand the understanding of big data for transportation operations, the value it could provide, and the implications for the : future direction of the U.S. Department of Transportation (USDOT) Connected Vehicle R...

Further results on geometric operators in quantum gravity

NARCIS (Netherlands)

Loll, R.

1996-01-01

We investigate some properties of geometric operators in canonical quantum gravity in the connection approach `a la Ashtekar, which are associated with volume, area and length of spatial regions. We motivate the construction of analogous discretized lattice quantities, compute various quantum

Handbook of Brain Connectivity

CERN Document Server

Jirsa, Viktor K

2007-01-01

Our contemporary understanding of brain function is deeply rooted in the ideas of the nonlinear dynamics of distributed networks. Cognition and motor coordination seem to arise from the interactions of local neuronal networks, which themselves are connected in large scales across the entire brain. The spatial architectures between various scales inevitably influence the dynamics of the brain and thereby its function. But how can we integrate brain connectivity amongst these structural and functional domains? Our Handbook provides an account of the current knowledge on the measurement, analysis and theory of the anatomical and functional connectivity of the brain. All contributors are leading experts in various fields concerning structural and functional brain connectivity. In the first part of the Handbook, the chapters focus on an introduction and discussion of the principles underlying connected neural systems. The second part introduces the currently available non-invasive technologies for measuring struct...

Power-electronic asset characteristics for HVDC-connected offshore grids

Energy Technology Data Exchange (ETDEWEB)

Heising, C.; Meyer, D.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Koochack Zadeh, M.; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

2012-07-01

Analysing offshore wind-farm applications as well as other converter-dominated grids, two key differences can be identified compared to conventional configurations: No relevant short-circuit power is available and no inertia is directly coupled to the AC grid. Within this paper, power-electronic asset characteristics for HVDC-connected offshore grids are presented which apply new principles allowing for better dynamic operation in the weak grids introduced. The capability is demonstrated using simulation results of an AC-multi-terminal system. (orig.)

Control of offshore wind farms with HVDC grid connection

Energy Technology Data Exchange (ETDEWEB)

Weigel, Stefan; Weise, Bernd; Poeller, Markus [DIgSILENT GmbH, Gomaringen (Germany)

2010-07-01

This paper analyzes various aspects related to the operation of HVDC connected offshore wind farms. The main interest is on the behavior during on- and offshore faults. Different control strategies for VSC-HVDC and ''classical'' thyristor-based HVDC links are presented and analyzed via network simulations. Wind generators with fully-rated converters and wind generators with doubly-fed induction generators are considered as generator types. The feasibility, advantages and disadvantages of the various options are discussed in detail. (orig.)

'Bluetooth' for radio-connecting short distance; Kinkyori wo musen setsuzokusuru 'Bluetooth'

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

'Bluetooth' is a new connection method for radio-connecting a short distance by means of mobile equipment including a note PC, PC peripheral equipment and portable telephone, using 2.4GHz ISM (Industrial Scientific Medical) band. It is capable of making a network without a complex operation, enabling data and audio communications. In May, 1998, an operation for deciding on the specifications was started under the leadership of five companies consisting of Ericsson, Nokia, Intel, IBM and Toshiba, with the specification version 1.0 completed in July, 1999 and opened to the public. (readable on http://www.bluetooth.com). Using such features as low power consumption, low cost and small size, the 'Bluetooth' will be mounted on various kinds of mobile equipment and developed in mobile PAN (Personal Area Network). (translated by NEDO)

Crushing Candy: The Free-to-Play Game in Its Connective Commodity Form

Directory of Open Access Journals (Sweden)

David B. Nieborg

2015-12-01

Full Text Available The goal of this article is to add a complementary perspective to the study of social network sites by surveying how the political economy of social media platforms relates to the structure of free-to-play games in their commodity form. Drawing on the theory of multisided markets and critical political economy, this article surveys the political economy of game apps and investigates how it is symbiotically related to the technological and economic logic underlying connective platforms operated by Google, Apple, Facebook, and Amazon. These social media platforms operate app stores that sustain the transformation of games as fixed, physically distributed products that follow a transaction logic, into digitally distributed, freely accessible, or “free-to-play” apps. Through a case study of the popular casual game Candy Crush Saga it is contended that the connective properties of social media platforms affect the form and format of game apps as cultural commodities. Candy Crush Saga developer King Digital Entertainment has been able to attract hundreds of millions of players and build a business model that combines the commodification of virtual items, connectivity, user attention, user data, and play. It is argued that the free-to-play commodity form comprises three commodity types: the product commodity, the “prosumer commodity,” and the player commodity. Furthermore, Candy Crush Saga ’s commodity form is structured by a platformed modality of cultural production and circulation and therefore embedded in the political economy of its host platform.

Grid connectivity issues and the importance of GCC. [GCC - Grid Code Compliance

Energy Technology Data Exchange (ETDEWEB)

Das, A.; Schwartz, M.-K. [GL Renewable Certification, Malleswaram, Bangalore (India)

2012-07-01

In India, the wind energy is concentrated in rural areas with a very high penetration. In these cases, the wind power has an increasing influence on the power quality on the grids. Another aspect is the influence of weak grids on the operation of wind turbines. Hence it becomes very much essential to introduce such a strong grid code which is particularly applicable to wind sector and suitable for Indian environmental grid conditions. This paper focuses on different international grid codes and their requirement with regard to the connection of wind farms to the electric power systems to mitigate the grid connectivity issues. The requirements include the ways to achieve voltage and frequency stability in the grid-tied wind power system. In this paper, comparative overview and analysis of the main grid connecting requirements will be conducted, comprising several national and regional codes from many countries where high wind penetration levels have been achieved or are expected in the future. The objective of these requirements is to provide wind farms with the control and regulation capabilities encountered in conventional power plants and are necessary for the safe, reliable and economic operation of the power system. This paper also provides a brief idea on the Grid Code Compliance (GCC) certification procedure implemented by the leading accredited certifying body like Germanischer Lloyd Renewables Certification (GL RC), who checks the conformity of the wind turbines as per region specific grid codes. (Author)

Stimulus-Elicited Connectivity Influences Resting-State Connectivity Years Later in Human Development: A Prospective Study.

Science.gov (United States)

Gabard-Durnam, Laurel Joy; Gee, Dylan Grace; Goff, Bonnie; Flannery, Jessica; Telzer, Eva; Humphreys, Kathryn Leigh; Lumian, Daniel Stephen; Fareri, Dominic Stephen; Caldera, Christina; Tottenham, Nim

2016-04-27

Although the functional architecture of the brain is indexed by resting-state connectivity networks, little is currently known about the mechanisms through which these networks assemble into stable mature patterns. The current study posits and tests the long-term phasic molding hypothesis that resting-state networks are gradually shaped by recurring stimulus-elicited connectivity across development by examining how both stimulus-elicited and resting-state functional connections of the human brain emerge over development at the systems level. Using a sequential design following 4- to 18-year-olds over a 2 year period, we examined the predictive associations between stimulus-elicited and resting-state connectivity in amygdala-cortical circuitry as an exemplar case (given this network's protracted development across these ages). Age-related changes in amygdala functional connectivity converged on the same regions of medial prefrontal cortex (mPFC) and inferior frontal gyrus when elicited by emotional stimuli and when measured at rest. Consistent with the long-term phasic molding hypothesis, prospective analyses for both connections showed that the magnitude of an individual's stimulus-elicited connectivity unidirectionally predicted resting-state functional connectivity 2 years later. For the amygdala-mPFC connection, only stimulus-elicited connectivity during childhood and the transition to adolescence shaped future resting-state connectivity, consistent with a sensitive period ending with adolescence for the amygdala-mPFC circuit. Together, these findings suggest that resting-state functional architecture may arise from phasic patterns of functional connectivity elicited by environmental stimuli over the course of development on the order of years. A fundamental issue in understanding the ontogeny of brain function is how resting-state (intrinsic) functional networks emerge and relate to stimulus-elicited functional connectivity. Here, we posit and test the long

Power charging and discharging characteristics of smes connected to artificial transmission line

International Nuclear Information System (INIS)

Nitta, T.; Okada, T.; Shirai, Y.

1985-01-01

To consider the characteristics of SMES and to investigate problems on the operations of SMES in power systems, we carried out some experiments on an experimental network. In the network, a small superconducting magnet is connected to a small synchronous generator through a double thyristorized converter and transformers. The generator is connected to the regional power system through artifitial transmission lines, AC power into or out of SMES and reactive power are controlled. Furthermore, a computer simulation program is made for the experimental system. The results of the simulation are compared with those of the experiments. For the experiments and the simulation, the harmonics current-flow, power-flow, characteristics of the generator and so on, are discussed

Sectional pipeline bundles. Design, fabrication and testing of a subsea pipeline connection system

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-08-01

The tests of the prototype system indicated that the system is applicable for connecting pipeline bundle sections. The overall performance of the system is therefore concluded to be satisfactory. Some modifications are required though, for improving the reliability of the system to the level required for offshore North Sea application. The tests showed that connection of the pipeline bundle sections can be performed for alignment tolerances larger than those expected during a typical subsea installation. Pull-in of bundle end sections can be performed with pull-in wires deployed from surface. The offshore tests showed that handling of wires must be done with great care to avoid possibility for wire entanglement, especially if a fully diverless system is to be used. The flowline connection tool was found to be suitable for final alignment of the individual spool ends. It was demonstrated that face to face contact between the hub faces in the connector was obtained after tie-in. Pressure tests showed that the connector could be sealed by the tie-in force applied by the connection tool tie-in system. However, the standard connector clamp which was used, was found to be insuficient for maintaining the connector effectively sealed after removal of the pull-in force applied by the connection tool. Based on the results proposals for improvements of the system are included. Improvements are applicable to the current system for connection of bundle sections or for tie-in operations, relating to conventional pipelines. The improvements also includes a strong connection clamp suitable for subsea use. The connection clamp will replace the standard clamp devise used in this project. (au) EFP-96. 41 refs.

Moral competence and brain connectivity: a resting-state fMRI study

Science.gov (United States)

Jung, Wi Hoon; Prehn, Kristin; Fang, Zhuo; Korczykowski, Marc; Kable, Joseph W.; Rao, Hengyi; Robertson, Diana C.

2016-01-01

Moral competence (MC) refers to the ability to apply certain moral orientations in a consistent and differentiated manner when judging moral issues. People greatly differ in terms of MC, however, little is known about how these differences are implemented in the brain. To investigate this question, we used functional magnetic resonance imaging and examined resting-state functional connectivity (RSFC) in n=31 individuals with MC scores in the highest 15% of the population and n=33 individuals with MC scores in the lowest 15%, selected from a large sample of 730 Master of Business Administration (MBA) students. Compared to individuals with lower MC, individuals with higher MC showed greater amygdala-ventromedial prefrontal connectivity, which may reflect better ability to cope with emotional conflicts elicited by moral dilemmas. Moreover, individuals with higher MC showed less inter-network connectivity between the amygdalar and fronto-parietal networks, suggesting a more independent operation of these networks. Our findings provide novel insights into how individual differences in moral judgment are associated with RSFC in brain circuits related to emotion processing and cognitive control. PMID:27456537

Linear Approach for Synchronous State Stability in Fully Connected PLL Networks

Directory of Open Access Journals (Sweden)

José R. C. Piqueira

2008-01-01

Full Text Available Synchronization is an essential feature for the use of digital systems in telecommunication networks, integrated circuits, and manufacturing automation. Formerly, master-slave (MS architectures, with precise master clock generators sending signals to phase-locked loops (PLLs working as slave oscillators, were considered the best solution. Nowadays, the development of wireless networks with dynamical connectivity and the increase of the size and the operation frequency of integrated circuits suggest that the distribution of clock signals could be more efficient if distributed solutions with fully connected oscillators are used. Here, fully connected networks with second-order PLLs as nodes are considered. In previous work, how the synchronous state frequency for this type of network depends on the node parameters and delays was studied and an expression for the long-term frequency was derived (Piqueira, 2006. Here, by taking the first term of the Taylor series expansion for the dynamical system description, it is shown that for a generic network with N nodes, the synchronous state is locally asymptotically stable.

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)

Comparative Analysis of Inversors for Small PV Systems Grid Connected

International Nuclear Information System (INIS)

Sidrach de Cardona, M.; Ramirez, L.

2001-01-01

The energy produced by a grid connected photovoltaic system is a function of weather conditions, mainly available radiation and temperature, photovoltaic array efficiency and inverter characteristics. The results obtained in experimental measurements with four small grid-connected inverters are described in this work. The main goal is to know the inverter performance in real operation conditions. For this purpose a 2 kW photovoltaic system has been used. These results allow us to know both the inverter efficiency and its output power quality. The following parameters have been evaluated as a function of output inverter power: efficiency, point of maximum power tracking, intensity and voltage waveform, total harmonic distortion and harmonic values to 31 order, frequency, power factor and reactive power. Other interesting parameters like stand-by energy consumption and daily losses due to the inverter threshold have also been analyzed. The results allow us to know the inverter features as a function of its real work point. In our comparative study it is possible to observe remarkable differences between the inverters; these results show how important it is to have a unique standard for inverters to photovoltaic grid-connected systems. (Author) 10 refs

Interaction of HPP Regulation Operation and Navigation at Water Structures

OpenAIRE

Možiešik, Ľudovít; Cabadaj, Roman; Čepcová, Zuzana

2009-01-01

Significant impact on navigation operation by hydropower plant (HPP) operation is mostly in diversion channels of hydropower plants, when these channels are used for navigation as well. It is caused by sudden changes in flow rate of hydropower plants, which is connected to providing of support services for electric power system. The objective of the research is to determine limits of acceptable hydropower plant operation or propose precautions which enable harmonization of opposing interests ...

HTTR operation monitoring with neural network in 30 days operation at 850degC

International Nuclear Information System (INIS)

Shimizu, Atsushi; Nabeshima, Kunihiko; Nakagawa, Shigeaki

2009-01-01

The High temperature engineering test reactor (HTTR) executed the rated power operation for 30days of the first time (850degC in temperature of the nuclear reactor outlet coolant) until March, 27th through April, 26th, 2007. In this operation, HTTR was observed according to the operation monitoring model with the neural network, and the detection performance of neural network was verified during slight changes of reactor state at rated power. The neural network used for the operation monitoring was an auto-associative network, where 31 input 31 outputs and the hidden layers were connected with 20 units by the hierarchy of three layer structure. Back-propagation algorithm was used for study rule. The operation monitoring model in initial study was constructed by using the power up data between 30% and rated power, which were randomly studied. The adjustment study during the operation monitoring changes the internal structure of the initial study model to follow the changes of reactor status, such as the burn-up of the nuclear fuel for the rated power operation. As a monitoring result, slight changes of reactor state by the control system operation were correctly detected, and the on-line application to an early anomaly diagnosis for HTTR facilities will be expected. (author)

Colombian ancillary services and international connections: Current weaknesses and policy challenges

International Nuclear Information System (INIS)

Carvajal, S.X.; Serrano, J.; Arango, S.

2013-01-01

Ancillary services are required to maintain the unity, stability, and quality of power systems. In Colombia these services are required to operate the national power system and the international connections with the neighboring countries. The system is influenced by factors ranging from system's topology to social and political aspects, such as the large number of terrorist attacks. In light of these particularities, we consider Colombia as a learning lab for ancillary services in the region. Colombia's power system relies on three ancillary services for its operation, namely frequency regulation, voltage control, and blackstart service. From 2010 Special Protection Systems were also added. In this paper we first analyze the technical aspects, operational restrictions, financial management, and the most relevant regulatory conditions of these ancillary services of the SIN. We also take into consideration the main regulatory characteristics and statistical data related to energy exchanges that have taken place between Colombia and Venezuela and Ecuador. Thereafter, we depict the main weaknesses and policy challenges that Colombia must address in order to increase the effectiveness and coverage of ancillary services in both the SIN and in the international interconnections. Finally, we propose new market oriented regulations to encourage investments and new tools for international connections. - Highlights: ► Blackout of 2007 forces Colombian regulator to improve security of power system. ► Four ancillary services are currently used for secure operation of Colombian system. ► Special Protection Systems service added in 2010. ► Frequency control is the only remunerated service in Colombia. ► Legislation should exist for remuneration of voltage control and black start services.

Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results

Science.gov (United States)

Humada, Ali M.; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M.; Ahmed, Mushtaq N.

2016-01-01

A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions. PMID:27035575

Power Management of the DC Bus Connected Converters in a Hybrid AC/DC Microgrid Tied to the Main Grid

Directory of Open Access Journals (Sweden)

Robert Antonio Salas-Puente

2018-03-01

Full Text Available In this paper, a centralized control strategy for the efficient power management of power converters composing a hybrid AC/DC microgrid is explained. The study is focused on the converters connected to the DC bus. The proposed power management algorithm is implemented in a microgrid central processor which is based on assigning several operation functions to each of the generators, loads and energy storage systems in the microgrid. The power flows between the DC and AC buses are studied in several operational scenarios to verify the proposed control. Experimental and simulation results demonstrate that the algorithm allows control of the power dispatch inside the microgrid properly by performing the following tasks: communication among power converters, the grid operator and loads; connection and disconnection of loads; control of the power exchange between the distributed generators and the energy storage system and, finally, supervision of the power dispatch limit set by the grid operator.

Optimisation for offshore wind farm cable connection layout using adaptive particle swarm optimisation minimum spanning tree method

DEFF Research Database (Denmark)

Hou, Peng; Hu, Weihao; Chen, Zhe

2016-01-01

operational requirement and this constraint should be considered during the MST formulation process. Hence, traditional MST algorithm cannot ensure a minimal cable investment layout. In this paper, a new method to optimize the offshore wind farm cable connection layout is presented. The algorithm...... with the optimized cable connection layout. The proposed method is compared with the MST and Dynamic MST (DMST) methods and simulation results show the effectiveness of the proposed method....

CODAC systems arrangement and connectivity

Energy Technology Data Exchange (ETDEWEB)

Gulati, Hitesh Kumar, E-mail: hkgulati@gmail.com; Beltran, David; Kuehn, Ingo; Kotamaki, Miikka; Makijarvi, Petri; Wallander, Anders

2013-10-15

Highlights: •The CODAC system is a distributed system and scattered in many buildings connected with cables. Building construction for ITER project is just started so volume reservation for different CODAC component is done based on the content of this paper. •The 2-D and 3-D diagrams have been prepared which are showing the location of different CODAC equipment and their connectivity. •The different requirements regarding raised access (false) floor, power requirements, heat load, installation, maintenance, redundancy, and segregation etc. have been considered. -- Abstract: The CODAC system is responsible for integrating all ITER plant system Instrumentation and Control systems and enabling operation of ITER machine as a single integrated facility. The different ITER plant systems and their Instrumentation and Control systems are distributed in several ITER buildings on the ITER platform. The CODAC systems have to interface with all these distributed plant system I and C systems. CODAC systems will be composed of several physical systems or components like networks, servers, workstations (terminals), large displays, PSH, storage systems etc. Several rooms in different buildings have been defined to house all above equipment. The site-wide CODAC network infrastructure will be based on a dual (redundant) star topology. The two redundant star points will house the core networking switches. These redundant core switches will be installed in different buildings. Cubicles used for network infrastructure are distributed among “hutches,” where a CODAC hutch is a room or area equipped with appropriate heating, ventilation, air conditioning and uninterruptible power which will be directly connected through two star points. The responsibility of CODAC infrastructure ends up to the plant system I and C cubicles so several passive CODAC network panels have identified in all I and C rooms of different plant buildings. This CODAC Network Panel will be the physical

Classification of domains of closed operators

International Nuclear Information System (INIS)

Lassner, G.; Timmermann, W.

1975-01-01

The structure of domains of determining closed operators in the Hilbert space by means of sequence spaces is investigated. The final classification provides three classes of these domains. Necessary and sufficient conditions of equivalence of these domains are obtained in the form of equivalency of corresponding sequences of natural numbers. Connection with the perturbation theory is mentioned [ru

Nonrandom network connectivity comes in pairs

Directory of Open Access Journals (Sweden)

Felix Z. Hoffmann

2017-02-01

Full Text Available Overrepresentation of bidirectional connections in local cortical networks has been repeatedly reported and is a focus of the ongoing discussion of nonrandom connectivity. Here we show in a brief mathematical analysis that in a network in which connection probabilities are symmetric in pairs, Pij = Pji, the occurrences of bidirectional connections and nonrandom structures are inherently linked; an overabundance of reciprocally connected pairs emerges necessarily when some pairs of neurons are more likely to be connected than others. Our numerical results imply that such overrepresentation can also be sustained when connection probabilities are only approximately symmetric.

Variational principles for nonpotential operators

CERN Document Server

Filippov, V M

1989-01-01

This book develops a variational method for solving linear equations with B-symmetric and B-positive operators and generalizes the method to nonlinear equations with nonpotential operators. The author carries out a constructive extension of the variational method to "nonvariational" equations (including parabolic equations) in classes of functionals which differ from the Euler-Lagrange functionals. In this connection, some new functions spaces are considered. Intended for mathematicians working in the areas of functional analysis and differential equations, this book would also prove useful for researchers in other areas and students in advanced courses who use variational methods in solving linear and nonlinear boundary value problems in continuum mechanics and theoretical physics.

ARIES NDA Robot operators' manual

International Nuclear Information System (INIS)

Scheer, N.L.; Nelson, D.C.

1998-05-01

The ARIES NDA Robot is an automation device for servicing the material movements for a suite of Non-destructive assay (NDA) instruments. This suite of instruments includes a calorimeter, a gamma isotopic system, a segmented gamma scanner (SGS), and a neutron coincidence counter (NCC). Objects moved by the robot include sample cans, standard cans, and instrument plugs. The robot computer has an RS-232 connection with the NDA Host computer, which coordinates robot movements and instrument measurements. The instruments are expected to perform measurements under the direction of the Host without operator intervention. This user's manual describes system startup, using the main menu, manual operation, and error recovery

Archives: Mathematics Connection

African Journals Online (AJOL)

Items 1 - 9 of 9 ... Archives: Mathematics Connection. Journal Home > Archives: Mathematics Connection. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. 1 - 9 of 9 Items. 2011 ...

The timescales of global surface-ocean connectivity.

Science.gov (United States)

Jönsson, Bror F; Watson, James R

2016-04-19

Planktonic communities are shaped through a balance of local evolutionary adaptation and ecological succession driven in large part by migration. The timescales over which these processes operate are still largely unresolved. Here we use Lagrangian particle tracking and network theory to quantify the timescale over which surface currents connect different regions of the global ocean. We find that the fastest path between two patches--each randomly located anywhere in the surface ocean--is, on average, less than a decade. These results suggest that marine planktonic communities may keep pace with climate change--increasing temperatures, ocean acidification and changes in stratification over decadal timescales--through the advection of resilient types.

Intermodal Passenger Connectivity Database -

Data.gov (United States)

Department of Transportation — The Intermodal Passenger Connectivity Database (IPCD) is a nationwide data table of passenger transportation terminals, with data on the availability of connections...

Zero-Voltage Ride-Through Capability of Single-Phase Grid-Connected Photovoltaic Systems

Directory of Open Access Journals (Sweden)

Zhen Zhang

2017-03-01

Full Text Available Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV systems, which should be of multiple-functionality. That is, the PV systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero is explored. It has been revealed that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL methods in the ZVRT operation are compared in terms of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems for ZVRT operation. Simulations are performed to verify the discussions. The results have demonstrated that the proposed method can help single-phase PV systems to temporarily ride through zero-voltage faults with good dynamics.

MedlinePlus Connect in Use

Science.gov (United States)

... MedlinePlus Connect in Use URL of this page: https://medlineplus.gov/connect/users.html MedlinePlus Connect in ... will change.) Old URLs New URLs Web Application https://apps.nlm.nih.gov/medlineplus/services/mpconnect.cfm? ...

The design, fabrication, operation and maintenance of (41) 400 H.P.-600 SCFM helium screw compressor systems (Five-year operation report)

International Nuclear Information System (INIS)

Pallaver, C.

1988-12-01

Fermi National Accelerator Laboratory (Fermilab) uses thirty-four (34) identical compressor systems connected to a common header to supply clean high pressure helium gas feeding 26 refrigerators supplying liquid helium to 777 super conducting magnets. There are seven (7) similar compressor packages in other locations. The purpose of this paper is (after five years of operation) to present all the problems, modifications and experiences associated with the design and operation of these compressor systems

An Efficient Connected Component Labeling Architecture for Embedded Systems

Directory of Open Access Journals (Sweden)

Fanny Spagnolo

2018-03-01

Full Text Available Connected component analysis is one of the most fundamental steps used in several image processing systems. This technique allows for distinguishing and detecting different objects in images by assigning a unique label to all pixels that refer to the same object. Most of the previous published algorithms have been designed for implementation by software. However, due to the large number of memory accesses and compare, lookup, and control operations when executed on a general-purpose processor, they do not satisfy the speed performance required by the next generation high performance computer vision systems. In this paper, we present the design of a new Connected Component Labeling hardware architecture suitable for high performance heterogeneous image processing of embedded designs. When implemented on a Zynq All Programmable-System on Chip (AP-SOC 7045 chip, the proposed design allows a throughput rate higher of 220 Mpixels/s to be reached using less than 18,000 LUTs and 5000 FFs, dissipating about 620 μJ.

MedlinePlus Connect: Web Service

Science.gov (United States)

... MedlinePlus Connect → Web Service URL of this page: https://medlineplus.gov/connect/service.html MedlinePlus Connect: Web ... will change.) Old URLs New URLs Web Application https://apps.nlm.nih.gov/medlineplus/services/mpconnect.cfm? ...

MedlinePlus Connect: Web Application

Science.gov (United States)

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MedlinePlus Connect: Technical Information

Science.gov (United States)

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MedlinePlus Connect: Email List

Science.gov (United States)

... MedlinePlus Connect → Email List URL of this page: https://medlineplus.gov/connect/emaillist.html MedlinePlus Connect: Email ... will change.) Old URLs New URLs Web Application https://apps.nlm.nih.gov/medlineplus/services/mpconnect.cfm? ...

CMS Connect

Science.gov (United States)

Balcas, J.; Bockelman, B.; Gardner, R., Jr.; Hurtado Anampa, K.; Jayatilaka, B.; Aftab Khan, F.; Lannon, K.; Larson, K.; Letts, J.; Marra Da Silva, J.; Mascheroni, M.; Mason, D.; Perez-Calero Yzquierdo, A.; Tiradani, A.

2017-10-01

The CMS experiment collects and analyzes large amounts of data coming from high energy particle collisions produced by the Large Hadron Collider (LHC) at CERN. This involves a huge amount of real and simulated data processing that needs to be handled in batch-oriented platforms. The CMS Global Pool of computing resources provide +100K dedicated CPU cores and another 50K to 100K CPU cores from opportunistic resources for these kind of tasks and even though production and event processing analysis workflows are already managed by existing tools, there is still a lack of support to submit final stage condor-like analysis jobs familiar to Tier-3 or local Computing Facilities users into these distributed resources in an integrated (with other CMS services) and friendly way. CMS Connect is a set of computing tools and services designed to augment existing services in the CMS Physics community focusing on these kind of condor analysis jobs. It is based on the CI-Connect platform developed by the Open Science Grid and uses the CMS GlideInWMS infrastructure to transparently plug CMS global grid resources into a virtual pool accessed via a single submission machine. This paper describes the specific developments and deployment of CMS Connect beyond the CI-Connect platform in order to integrate the service with CMS specific needs, including specific Site submission, accounting of jobs and automated reporting to standard CMS monitoring resources in an effortless way to their users.

Design of serially connected district heating heat pumps utilising a geothermal heat source

DEFF Research Database (Denmark)

Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

2017-01-01

The design of two heat pumps (HP), connected in series, was investigated for operation in the district heating (DH) network of the Greater Copenhagen area, Denmark. The installation was dimensioned to supply 7.2 MW of heat at a temperature of 85 °C. The heat pumps utilise a geothermal heat source...

New Quartz Crystal Oscillators Using the Current-Feedback Operational Amplifier

OpenAIRE

Muhammad Taher Abuelma'atti; Ahmad Al-Ghazwani

2000-01-01

New crystal oscillators using the current-feedback operational-amplifier (CFOA) are presented. Each circuit uses one CFOA, a crystal and, at most, five externally connected passive elements. Experimental results are included.

Operation of river systems. The Otra river

International Nuclear Information System (INIS)

Harby, A.; Vaskinn, K.A.; Wathne, M.; Heggenes, J.; Saltveit, S.J.

1993-12-01

The purpose of the project described in this report was to prepare an operative tool for making decisions about the operation of the power system on the river Otra (Norway) with regard to how this operation might affect the various users of the river system. Above all this affects fish, outdoor life and esthetic values. The connection between water quality and volume of discharge has been examined in a sub project. How suitable parts of the river are as habitats for trout has been simulated on a computer. From field investigation it is concluded that near the Steinfoss power station the physical conditions for trout depend on the operation of the river system. Outdoor life is not much affected downstream Vikeland. 11 refs., 22 figs., 2 tabs

Simulation and parallel connection of step-down piezoelectric transformers

International Nuclear Information System (INIS)

Thang, Vo Viet; Kim, In Sung; Jeong, Soon Jong; Kim, Min Soo; Song, Jae Sung

2012-01-01

Piezoelectric transformers have been used widely in electronic circuits due to advantages such as high efficiency, miniaturization and no flammability; however the output power has been limited. For overcoming this drawback, some research has recently been focused on connections between piezoelectric transformers. Based on these operations, the output power has been improved compared to the single operation. Parallel operation of step-down piezoelectric transformers is presented in this paper. An important factor affecting the parallel operation of piezoelectric transformer was the resonance frequency, and a small difference in resonance frequencies was obtained with transformers having the same dimensions and fabricating processes. The piezoelectric transformers were found to operate in first radial mode at a frequency of 68 kHz. An equivalent circuit was used to investigate parallel driving of piezoelectric transformers and then to compare the result with experimental observations. The electrical characteristics, including the output voltage, output power and efficient were measured at a matching resistive load. Effects of frequency on the step-down ratio and of the input voltage on the power properties in the simulation were similar to the experimental results. The output power of the parallel operation was 35 W at a load of 50 Ω and an input voltage of 100 V; the temperature rise was 30 .deg. C and the efficiency was 88%.

Multiobjective Synergistic Scheduling Optimization Model for Wind Power and Plug-In Hybrid Electric Vehicles under Different Grid-Connected Modes

Directory of Open Access Journals (Sweden)

Liwei Ju

2014-01-01

Full Text Available In order to promote grid’s wind power absorptive capacity and to overcome the adverse impacts of wind power on the stable operation of power system, this paper establishes benefit contrastive analysis models of wind power and plug-in hybrid electric vehicles (PHEVs under the optimization goal of minimum coal consumption and pollutant emission considering multigrid connected modes. Then, a two-step adaptive solving algorithm is put forward to get the optimal system operation scheme with the highest membership degree based on the improved ε constraints method and fuzzy decision theory. Thirdly, the IEEE36 nodes 10-unit system is used as the simulation system. Finally, the sensitive analysis for PHEV’s grid connected number is made. The result shows the proposed algorithm is feasible and effective to solve the model. PHEV’s grid connection could achieve load shifting effect and promote wind power grid connection. Especially, the optimization goals reach the optimum in fully optimal charging mode. As PHEV’s number increases, both abandoned wind and thermal power generation cost would decrease and the peak and valley difference of load curve would gradually be reduced.

Reactor operation method

International Nuclear Information System (INIS)

Osumi, Katsumi; Miki, Minoru.

1979-01-01

Purpose: To prevent stress corrosion cracks by decreasing the dissolved oxygen and hydrogen peroxide concentrations in the coolants within a reactor container upon transient operation such as at the start-up or shutdown of bwr type reactors. Method: After a condensate has been evacuated, deaeration operation is conducted while opening a main steam drain line, as well as a main steam separation valve and a by-pass valve in a turbine by-pass line connecting the main steam line and the condenser without by way of a turbine, and the reactor is started-up by the extraction of control rods after the concentration of dissolved oxygen in the cooling water within a pressure vessel has been decreased below a predetermined value. Nuclear heating is started after the reactor water has been increased to about 150 0 C by pump heating after the end of the deaeration operation for preventing the concentration of hydrogen peroxide and oxygen in the reactor water from temporarily increasing immediately after the start-up. The corrosive atmosphere in the reactor vessel can thus be moderated. (Horiuchi, T.)

Overcurrent protection issues due to the DG connection

Energy Technology Data Exchange (ETDEWEB)

Gomez, J.C.; Tourn, D.H.; Amatti, J.C. [Rio Cuarto National University (IPSEP/UNRC), Cordoba (Argentina). Electric Power Systems Protection Institute], E-mail: jcgomez@ing.unrc.edu.ar

2009-07-01

The present energy crisis drives to carry to an extreme the use of all the available energy sources, which need to be connected to the network in their closest point. Traditional electric systems are changing their characteristics, in what concerns to structure, operation, and especially on protection methodologies. The new protection problems of the different parts of the system are explained. The solution presents positive and negative aspects that impact the utility and the customer in different ways. A revision about interconnection international standards is presented. The contributions of generators to short circuit currents is analyzed, especially the double fed generator. Philosophy changes are studied, such as: fault current bi directionality, modification of the protection reach, failures of the overcurrent coordination due to current share, etc. Solicitations to DG due to the normal unbalance of distribution systems are also studied. It is analyzed the discrepancy between the customers and utilities regarding the 'islanding operation', presenting the semi-rigid connection. The changes in the coordination methodology fusible-recloser are also studied, proposing a new methodology to check this coordination. Experimental results on 13.2 kV are presented that relate the deionization without zero current, with arc length and with 'network power to DG power ratio'. It is concluded that DG application offers technical-economic advantages so much to the utility as to the user; and that the technology for these new protection approaches is already available, requiring of investments whose justification needs of a specific analysis for each particular case. (author)

Fuzzy Secondary Controller for Autonomous Stand-alone and Grid-connected AC Microgrid

DEFF Research Database (Denmark)

Neves, Rodolpho V. A.; Machado, Ricardo Q.; Oliveira, Vilma A.

2016-01-01

The present paper adresses the AC microgrid control issue using the hierarchical control structure and droop controllers for load sharing. Once the droop controllers impose an operation with frequency and voltage deviations, depending on the load and droop parameters, a hierarchical control...... structure must be added to change the droop controller operating points. The hierarchical controllers operate with local measurements and shared signals from communication links among the distributed generation systems connected to the microgrid. Depending on the geographical size of the microgrid......, the communication links can be economically unviable. This paper thus proposes a fuzzy secondary controller for AC microgrids to reduce the link communication dependency by using only local measurements. The simulation results show that the deviations as happened with the conventional secondary controllers can...

78 FR 55684 - ConnectED Workshop

Science.gov (United States)

2013-09-11

... tools move everything from homework assignments to testing into the cloud. The workshop will explore possible strategies to connect virtually all of our students to next-generation broadband in a timely, cost-effective way. It will also share promising practices, from NTIA's Broadband Technology Opportunities...

Estuary-ocean connectivity: fast physics, slow biology.

Science.gov (United States)

Raimonet, Mélanie; Cloern, James E

2017-06-01

Estuaries are connected to both land and ocean so their physical, chemical, and biological dynamics are influenced by climate patterns over watersheds and ocean basins. We explored climate-driven oceanic variability as a source of estuarine variability by comparing monthly time series of temperature and chlorophyll-a inside San Francisco Bay with those in adjacent shelf waters of the California Current System (CCS) that are strongly responsive to wind-driven upwelling. Monthly temperature fluctuations inside and outside the Bay were synchronous, but their correlations weakened with distance from the ocean. These results illustrate how variability of coastal water temperature (and associated properties such as nitrate and oxygen) propagates into estuaries through fast water exchanges that dissipate along the estuary. Unexpectedly, there was no correlation between monthly chlorophyll-a variability inside and outside the Bay. However, at the annual scale Bay chlorophyll-a was significantly correlated with the Spring Transition Index (STI) that sets biological production supporting fish recruitment in the CCS. Wind forcing of the CCS shifted in the late 1990s when the STI advanced 40 days. This shift was followed, with lags of 1-3 years, by 3- to 19-fold increased abundances of five ocean-produced demersal fish and crustaceans and 2.5-fold increase of summer chlorophyll-a in the Bay. These changes reflect a slow biological process of estuary-ocean connectivity operating through the immigration of fish and crustaceans that prey on bivalves, reduce their grazing pressure, and allow phytoplankton biomass to build. We identified clear signals of climate-mediated oceanic variability in this estuary and discovered that the response patterns vary with the process of connectivity and the timescale of ocean variability. This result has important implications for managing nutrient inputs to estuaries connected to upwelling systems, and for assessing their responses to changing

75 FR 70162 - Presumptive Service Connection for Diseases Associated With Persian Gulf War Service: Functional...

Science.gov (United States)

2010-11-17

... Diseases Associated With Persian Gulf War Service: Functional Gastrointestinal Disorders AGENCY: Department... theater of operations during the Persian Gulf War. DATES: Comments must be received by VA on or before... Service Connection for Diseases Associated With Persian Gulf War Service: Functional Gastrointestinal...

Performance of conical abutment (Morse Taper) connection implants: a systematic review.

Science.gov (United States)

Schmitt, Christian M; Nogueira-Filho, Getulio; Tenenbaum, Howard C; Lai, Jim Yuan; Brito, Carlos; Döring, Hendrik; Nonhoff, Jörg

2014-02-01

In this systematic review, we aimed to compare conical versus nonconical implant-abutment connection systems in terms of their in vitro and in vivo performances. An electronic search was performed using PubMed, Embase, and Medline databases with the logical operators: "dental implant" AND "dental abutment" AND ("conical" OR "taper" OR "cone"). Names of the most common conical implant-abutment connection systems were used as additional key words to detect further data. The search was limited to articles published up to November 2012. Recent publications were also searched manually in order to find any relevant studies that might have been missed using the search criteria noted above. Fifty-two studies met the inclusion criteria and were included in this systematic review. As the data and methods, as well as types of implants used was so heterogeneous, this mitigated against the performance of meta-analysis. In vitro studies indicated that conical and nonconical abutments showed sufficient resistance to maximal bending forces and fatigue loading. However, conical abutments showed superiority in terms of seal performance, microgap formation, torque maintenance, and abutment stability. In vivo studies (human and animal) indicated that conical and nonconical systems are comparable in terms of implant success and survival rates with less marginal bone loss around conical connection implants in most cases. This review indicates that implant systems using a conical implant-abutment connection, provides better results in terms of abutment fit, stability, and seal performance. These design features could lead to improvements over time versus nonconical connection systems. © 2013 Wiley Periodicals, Inc.

Exploring connectivity with large-scale Granger causality on resting-state functional MRI.

Science.gov (United States)

DSouza, Adora M; Abidin, Anas Z; Leistritz, Lutz; Wismüller, Axel

2017-08-01

Large-scale Granger causality (lsGC) is a recently developed, resting-state functional MRI (fMRI) connectivity analysis approach that estimates multivariate voxel-resolution connectivity. Unlike most commonly used multivariate approaches, which establish coarse-resolution connectivity by aggregating voxel time-series avoiding an underdetermined problem, lsGC estimates voxel-resolution, fine-grained connectivity by incorporating an embedded dimension reduction. We investigate application of lsGC on realistic fMRI simulations, modeling smoothing of neuronal activity by the hemodynamic response function and repetition time (TR), and empirical resting-state fMRI data. Subsequently, functional subnetworks are extracted from lsGC connectivity measures for both datasets and validated quantitatively. We also provide guidelines to select lsGC free parameters. Results indicate that lsGC reliably recovers underlying network structure with area under receiver operator characteristic curve (AUC) of 0.93 at TR=1.5s for a 10-min session of fMRI simulations. Furthermore, subnetworks of closely interacting modules are recovered from the aforementioned lsGC networks. Results on empirical resting-state fMRI data demonstrate recovery of visual and motor cortex in close agreement with spatial maps obtained from (i) visuo-motor fMRI stimulation task-sequence (Accuracy=0.76) and (ii) independent component analysis (ICA) of resting-state fMRI (Accuracy=0.86). Compared with conventional Granger causality approach (AUC=0.75), lsGC produces better network recovery on fMRI simulations. Furthermore, it cannot recover functional subnetworks from empirical fMRI data, since quantifying voxel-resolution connectivity is not possible as consequence of encountering an underdetermined problem. Functional network recovery from fMRI data suggests that lsGC gives useful insight into connectivity patterns from resting-state fMRI at a multivariate voxel-resolution. Copyright © 2017 Elsevier B.V. All

Geometry and physics of pseudodifferential operators on manifolds

DEFF Research Database (Denmark)

Esposito, Giampiero; Napolitano, George M.

2015-01-01

A review is made of the basic tools used in mathematics to define a calculus for pseudodifferential operators on Riemannian manifolds endowed with a connection: existence theorem for the function that generalizes the phase; analogue of Taylor's theorem; torsion and curvature terms in the symbolic...

Handbook of networking & connectivity

CERN Document Server

McClain, Gary R

1994-01-01

Handbook of Networking & Connectivity focuses on connectivity standards in use, including hardware and software options. The book serves as a guide for solving specific problems that arise in designing and maintaining organizational networks.The selection first tackles open systems interconnection, guide to digital communications, and implementing TCP/IP in an SNA environment. Discussions focus on elimination of the SNA backbone, routing SNA over internets, connectionless versus connection-oriented networks, internet concepts, application program interfaces, basic principles of layering, proto

Discussion of Minos Mine operating system

Energy Technology Data Exchange (ETDEWEB)

Pan, B.

1991-10-01

The MINOS (mine operating system), which is used in the majority of British collieries, provides central control at the surface for the machinery and environmental equipment distributed throughout the mine. Installed equipment, including face machinery, conveyors, pumps, fans and sensors are connected to local outstations which all communicate with the control system via a single run of signal cable. The article discusses the system particularly its use in the Automated Control System of Underground Mining Locomotives (ACSUML). The discussion includes the use of MINOS to improve wagon identification, the operating principle of ACSUML and the possibilities of a driverless locomotive. 2 figs.

Procedures and practices for day-to-day operation

International Nuclear Information System (INIS)

Distler, K.

1986-01-01

This lecture deals with problems of safe plant operation under day-to-day conditions. Operation, maintenance and surveillance have to be organized in a preventive manner. It will be shown that nearly all expected jobs and proceedings can be done rule-based. The connection of documentation and work preparation will be lined out. Moreover, the need for control and quality assurance for nearly all proceedings will be pointed out. The question of communication and scheduling will be touched. (orig.)

Text of a Protocol between the Agency and the Governments of Norway and the United States of America in Connection with the Application of Safeguards under a Co-Operation Agreement between the Two Governments

International Nuclear Information System (INIS)

1973-01-01

The text of a protocol between the Agency and the Governments of Norway and the United States of America in connection with the application of safeguards under the Agreement for Co-operation between the Government of the United States of America and the Government of Norway Concerning Civil Uses of Atomic Energy signed on 4 May 1967, as amended, is reproduced herein for the information of all Members. The protocol entered into force on 25 September 1973 pursuant to Section 4.

Control Networks in Paediatric Tourette Syndrome Show Immature and Anomalous Patterns of Functional Connectivity

Science.gov (United States)

Church, Jessica A.; Fair, Damien A.; Dosenbach, Nico U. F.; Cohen, Alexander L.; Miezin, Francis M.; Petersen, Steven E.; Schlaggar, Bradley L.

2009-01-01

Tourette syndrome (TS) is a developmental disorder characterized by unwanted, repetitive behaviours that manifest as stereotyped movements and vocalizations called "tics". Operating under the hypothesis that the brain's control systems may be impaired in TS, we measured resting-state functional connectivity MRI (rs-fcMRI) between 39 previously…

Quantitative Analysis Method of Output Loss due to Restriction for Grid-connected PV Systems

Science.gov (United States)

Ueda, Yuzuru; Oozeki, Takashi; Kurokawa, Kosuke; Itou, Takamitsu; Kitamura, Kiyoyuki; Miyamoto, Yusuke; Yokota, Masaharu; Sugihara, Hiroyuki

Voltage of power distribution line will be increased due to reverse power flow from grid-connected PV systems. In the case of high density grid connection, amount of voltage increasing will be higher than the stand-alone grid connection system. To prevent the over voltage of power distribution line, PV system's output will be restricted if the voltage of power distribution line is close to the upper limit of the control range. Because of this interaction, amount of output loss will be larger in high density case. This research developed a quantitative analysis method for PV systems output and losses to clarify the behavior of grid connected PV systems. All the measured data are classified into the loss factors using 1 minute average of 1 second data instead of typical 1 hour average. Operation point on the I-V curve is estimated to quantify the loss due to the output restriction using module temperature, array output voltage, array output current and solar irradiance. As a result, loss due to output restriction is successfully quantified and behavior of output restriction is clarified.

Method of roundtrip operations in superdeep wells

Energy Technology Data Exchange (ETDEWEB)

Lozovoy, A.F.; Petrosyants, A.N.; Sapozhnik, S.A.; Yeganov, A.I.

1984-01-01

The purpose of the invention is to protect the sites of cable connection when they pass through the guide and suspension blocks and the final section of the cable on the last drum from crushing. This goal is achieved because according to the method of roundtrip operations in superdeep wells which includes winding the cable from the drum, connection of the end of the cable with the cable of the next drum, lowering the cable through the guide and suspension blocks by lifting and lowering the suspension block, the site of cable connection is pulled through the guide and suspension blocks by lifting the suspension block with wedged, loaded end of the cable, and on the last drum a layer of cable is left in which the radial load on the first layer of cable winding on the drum should not exceed the permissible radial load on the cable.

New special operators in W-gravity theories

International Nuclear Information System (INIS)

Rama, S.K.

1991-01-01

This paper reports on special physical operators of W 3 -gravity having non-trivial ghost sectors. Some of these operators may be viewed as the Liouville dressings of the energy operator of the Ising model coupled to two-dimensional (2D) gravity and this fills in the gap in the connection between pure W 3 -gravity and Ising model coupled to 2D gravity found in the authors' previous work. The authors formulate a selection rule required for the calculation of correlators in W-gravity theories. Using this rule, the authors construct the non-ghost part of the new operators of W N -gravity and find that they represent the (N,N + 1) minimal model operators from both inside and outside the minimal table. Along the way the authors obtain the canonical spectrum of W N -gravity for all N

New type shift operators for circular well potential in two dimensions

International Nuclear Information System (INIS)

Sun Guohua; Dong Shihai

2010-01-01

New type shift operators for circular well potential in two dimensions are identified. These so-called shift operators connect those quantum systems with the different potentials but with same energy spectrum. It should be noted that these operators depend on both the radial circular and angular variables r and φ. We find that the operators P ± =P x ±P y play the role of the shift operators. The radial linear momentum P r =-ih(∂)/(∂r) , the angular momentum L z =-ih(∂)/(∂φ) and the Hamiltonian form a complete set of commuting operators with the SO(2) symmetry.

Airport industry connectivity report: 2015

NARCIS (Netherlands)

Boonekamp, T.; Lieshout, R.; Burghouwt, G.

2015-01-01

This report is an update of the 'Airport Industry Connectivity Report 2004-2014'. It's focused on more recent developments and charting how Europe’s connectivity has evolved over the past 12 months. Airport connectivity is an increasingly discussed topic in European policy circles. With good reason.

SMES application for frequency control during islanded microgrid operation

International Nuclear Information System (INIS)

Kim, A-Rong; Kim, Gyeong-Hun; Heo, Serim; Park, Minwon; Yu, In-Keun; Kim, Hak-Man

2013-01-01

Highlights: ► The operating characteristics of SMES for the frequency control of an islanded microgrid were investigated. ► The SMES contributes well for frequency control in the islanded operation. ► A dual and a single magnet type of SMES have been compared to demonstrate the performances. -- Abstract: This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail

SMES application for frequency control during islanded microgrid operation

Energy Technology Data Exchange (ETDEWEB)

Kim, A-Rong, E-mail: haven21c@changwon.ac.kr [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Kim, Gyeong-Hun; Heo, Serim; Park, Minwon [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, Sarim-dong, Changwon 641-773 (Korea, Republic of); Kim, Hak-Man [University of Incheon, Songdo-dong, Incheon 406-772 (Korea, Republic of)

2013-01-15

Highlights: ► The operating characteristics of SMES for the frequency control of an islanded microgrid were investigated. ► The SMES contributes well for frequency control in the islanded operation. ► A dual and a single magnet type of SMES have been compared to demonstrate the performances. -- Abstract: This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail.

Optimal Locations of Bus Stops Connecting Subways near Urban Intersections

Directory of Open Access Journals (Sweden)

Yuan Cui

2015-01-01

Full Text Available Unsuitable locations of bus stops which provide feeder transportation connecting subways near urban intersections usually lead to the low efficiency of public transport and level of passenger service. A multiobjective optimization model to distribute such stop locations is proposed to attain the shortest total walk distance of passengers and minimum delay time of cars through intersections and travel time of buses. The Pareto frontier and optimal solutions for the proposed model are given by the distance-based and enumerative methods. The Xizhimen bus stop is selected to implement case studies for verifying the validity of the proposed model. The analysis of sensitivity on possible solutions is also carried out in the case studies. The results show that the proposed model is capable of optimizing the locations of bus stops connecting subways near intersections and helpful to improve the level of passengers service and operational efficiency of public transportation.

New Ways in the Cognitive Dimension of Information Operations

Directory of Open Access Journals (Sweden)

Haig Zsolt

2017-06-01

Full Text Available In this paper the authors introduce the cognitive dimension that is becoming more and more important in the field of information operations with special regard to psychological operations (PSYOPS. The strengthening role of influencing skills and technological progress has created new avenues and opportunities in the military field. The paper seeks to point out the relationship between marketing and PSYOPS. In connection with this, the study intends to present a new approach to PSYOPS that can achieve the operational goals which set by the leader by applying guerrilla marketing tools and methods.

Control and operation of distributed generation in distribution systems

DEFF Research Database (Denmark)

Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte

2011-01-01

Many distribution systems nowadays have significant penetration of distributed generation (DG)and thus, islanding operation of these distribution systems is becoming a viable option for economical and technical reasons. The DG should operate optimally during both grid-connected and island...... algorithm, which uses average rate of change off requency (Af5) and real power shift RPS), in the islanded mode. RPS will increase or decrease the power set point of the generator with increasing or decreasing system frequency, respectively. Simulation results show that the proposed method can operate...

Operational costs induced by fluctuating wind power production in Germany and Scandinavia

Energy Technology Data Exchange (ETDEWEB)

Meibom, P. [Risoe National Lab., DTU, System Analysis Dept., Roskilde (Denmark); Weber, C. [Univ. Duisburg-Essen, Chai og Energy Management (Germany); Barth, R.; Brand, H. [Univ. of Stuttgart, Inst. of Energy Economics and the Rational Use of Energy (Germany)

2007-05-15

Adding wind power generation in a power system changes the operational patterns of the existing units due to the variability and unpredictability of wind power production. For large amounts of wind power production the expectation is that the operational costs of the other power plants will increase due to more operation time in part-load and more start-ups. The change in operational costs induced by the wind power production can only be calculated by comparing the operational costs in two power system configurations: with wind power production and with alternative production having properties like conventional production, i.e. being predictable and less variable. The choice of the characteristics of the alternative production is not straight forward and will therefore influence the operational costs induced by wind power production. This paper presents a method for calculating the change in operational costs due to wind power production using a stochastic optimization model covering the power systems in Germany and the Nordic countries. Two cases of alternative production are used to calculate the change in operational costs namely perfectly predictable wind power production enabling calculation of the costs connected to unpredictability, and constant wind power production enabling calculation of the operational costs connected to variability of wind power production. A 2010 case with three different wind power production penetration levels is analysed in the paper. (au)

Importance Of Penetration Testing For Legacy Operating System

Directory of Open Access Journals (Sweden)

Poorvi Bhatt

2017-12-01

Full Text Available Penetration testing is very important technique to find vulnerabilities in commercial networks. There are various techniques for ethical hacking via penetration testing. This report explains a white hat hacker approach of penetration testing. I have performed this test on private network where three PCs are connected through LAN via switch and without firewall. This network is not connected with Internet. All the PCs have windows operating system. The attacker host has windows server 2003 with Service Pack1 second host has windows XP with Service Pack 2 and third host has windows 2000 with service pack 4.

High-Efficiency High Step-Up DC-DC Converter with Dual Coupled Inductors for Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Forouzesh, Mojtaba; Shen, Yanfeng; Siwakoti, Yam Prasad

2018-01-01

with a common ground connection of the input and output make the proposed topology a proper candidate for a transformer-less grid connected photovoltaic systems. The operating performance, analysis and mathematical derivations of the proposed dc-dc converter have been demonstrated in the paper. Moreover......This paper introduces a non-isolated high step-up dc-dc converter with dual coupled inductors suitable for distributed generation applications. By implementing an input parallel connection, the proposed dc-dc structure inherits shared input current with low ripple, which also requires small...... capacitive filter at its input. Moreover, this topology can reach high voltage gain by using dual coupled inductors in series connection at the output stage. The proposed converter uses active clamp circuits with a shared clamp capacitor for the main switches. In addition to the active clamp circuit...

Connected Traveler

Energy Technology Data Exchange (ETDEWEB)

2016-06-01

The Connected Traveler framework seeks to boost the energy efficiency of personal travel and the overall transportation system by maximizing the accuracy of predicted traveler behavior in response to real-time feedback and incentives. It is anticipated that this approach will establish a feedback loop that 'learns' traveler preferences and customizes incentives to meet or exceed energy efficiency targets by empowering individual travelers with information needed to make energy-efficient choices and reducing the complexity required to validate transportation system energy savings. This handout provides an overview of NREL's Connected Traveler project, including graphics, milestones, and contact information.

Implementation of neural networks on 'Connection Machine'

International Nuclear Information System (INIS)

Belmonte, Ghislain

1990-12-01

This report is a first approach to the notion of neural networks and their possible applications within the framework of artificial intelligence activities of the Department of Applied Mathematics of the Limeil-Valenton Research Center. The first part is an introduction to the field of neural networks; the main neural network models are described in this section. The applications of neural networks in the field of classification have mainly been studied because they could more particularly help to solve some of the decision support problems dealt with by the C.E.A. As the neural networks perform a large number of parallel operations, it was therefore logical to use a parallel architecture computer: the Connection Machine (which uses 16384 processors and is located at E.T.C.A. Arcueil). The second part presents some generalities on the parallelism and the Connection Machine, and two implementations of neural networks on Connection Machine. The first of these implementations concerns one of the most used algorithms to realize the learning of neural networks: the Gradient Retro-propagation algorithm. The second one, less common, concerns a network of neurons destined mainly to the recognition of forms: the Fukushima Neocognitron. The latter is studied by the C.E.A. of Bruyeres-le-Chatel in order to realize an embedded system (including hardened circuits) for the fast recognition of forms [fr

Dynamic parameterization and ladder operators for the Kratzer molecular potential

International Nuclear Information System (INIS)

Devi, O Babynanda; Singh, C Amuba

2014-01-01

Introducing independent parameters k and δ to represent the strength of the attractive and repulsive components, respectively, we write the Kratzer molecular potential as V(k,δ)=(ℏ 2 /2 m)(−k/r+δ(δ−1)/r 2 ). This parameterisation is not only natural, but also convenient for the construction of ladder operators for the system. Adopting the straightforward method of deriving recurrence relations among confluent hypergeometric functions, we construct seven pairs of ladder operators for the Kratzer potential system. Detailed analysis of the laddering actions of these operators is given to show that they connect eigenstates of equal energy but belong to a hierarchy of Kratzer potential systems corresponding to different values of the parameters k and δ. Significantly, it is pointed out that it may not be possible to construct, in the position representation, a ladder operator which would connect different eigenstates belonging to the same potential V(k,δ). Transition to the hydrogen atom case is discussed. A number (14 altogether) of functional relations among the confluent hypergeometric functions have been derived and reported separately in an appendix. (paper)

Reliable file sharing in distributed operating system using web RTC

Science.gov (United States)

Dukiya, Rajesh

2017-12-01

Since, the evolution of distributed operating system, distributed file system is come out to be important part in operating system. P2P is a reliable way in Distributed Operating System for file sharing. It was introduced in 1999, later it became a high research interest topic. Peer to Peer network is a type of network, where peers share network workload and other load related tasks. A P2P network can be a period of time connection, where a bunch of computers connected by a USB (Universal Serial Bus) port to transfer or enable disk sharing i.e. file sharing. Currently P2P requires special network that should be designed in P2P way. Nowadays, there is a big influence of browsers in our life. In this project we are going to study of file sharing mechanism in distributed operating system in web browsers, where we will try to find performance bottlenecks which our research will going to be an improvement in file sharing by performance and scalability in distributed file systems. Additionally, we will discuss the scope of Web Torrent file sharing and free-riding in peer to peer networks.

Impact of Rural Grid-Connected Photovoltaic Generation Systems on Power Quality

Directory of Open Access Journals (Sweden)

Rita Pinto

2016-09-01

Full Text Available Photovoltaic (PV generation systems have been increasingly used to generate electricity from renewable sources, attracting a growing interest. Recently, grid connected PV micro-generation facilities in individual homes have increased due to governmental policies as well as greater attention by industry. As low voltage (LV distribution systems were built to make energy flow in one direction, the power feed-in of PV generation in rural low-voltage grids can influence power quality (PQ as well as facility operation and reliability. This paper presents results on PQ analysis of a real PV generation facility connected to a rural low-voltage grid. Voltage fluctuations and voltage harmonic contents were observed. Statistical analysis shows a negative impact on PQ produced by this PV facility and also that only a small fraction of the energy available during a sunny day is converted, provoking losses of revenue and forcing the converter to work in an undesirable operating mode. We discuss the disturbances imposed upon the grid and their outcome regarding technical and economic viability of the PV system, as well as possible solutions. A low-voltage grid strengthening has been suggested and implemented. After that a new PQ analysis shows an improvement in the impact upon PQ, making this facility economically viable.

Operator reliability assessment system (OPERAS)

International Nuclear Information System (INIS)

Spurgin, A.J.; Hallam, J.W.; Spurgin, J.P.; Singh, A.

1991-01-01

The paper gives an overview of the OPERAS project. It discusses the background which led to the design of the PC-based data collection and analysis system connected to plant training simulators including those used for nuclear power plants. The usefulness of a system like OPERAS was perceived during an earlier EPRI project, the Operator Reliability Experiments project, by EPRI and PG and E. The data collection and analysis approaches used in OPERAS were developed during the ORE project. The paper not only discusses the design of OPERAS but discusses the functions performed and the current experiences with the two prototype systems. Also listed are potential uses of OPERAS by utility personnel in Operations, Training and PRA groups

Ideal Convergence of k-Positive Linear Operators

Directory of Open Access Journals (Sweden)

Akif Gadjiev

2012-01-01

Full Text Available We study some ideal convergence results of k-positive linear operators defined on an appropriate subspace of the space of all analytic functions on a bounded simply connected domain in the complex plane. We also show that our approximation results with respect to ideal convergence are more general than the classical ones.

Connectable solar air collectors

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Bosanac, M.

2002-02-01

The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

On the connections between the classical and quantum-mechanical Kepler problems

International Nuclear Information System (INIS)

Dahl, J.P.; Jorgensen, T.G.

1993-01-01

The Runge-Lenz vector, which accounts for the accidental degeneracy of the non-relativistic Kepler problem, has been the subject matter of many studies, both in quantum mechanics and in classical mechanics. Much less attention has been paid to the Johnson-Lippmann operator which accounts for the accidental degeneracy of the relativistic Kepler problem in Dirac's quantum-mechanical description. In the present communication we discuss the properties of the Johnson-Lippmann operator. We show its relation to the non-relativistic Runge-Lenz vector and draw a connection to Sommerfield's early discussion of the relativistic Kepler problem. This enables us, inter alia, to give an explanation of the apparent coincidence of the energy expressions of the two theories

REPUTATIONAL AND OPERATIONAL RISKS IN EUROPEAN BANKS

Directory of Open Access Journals (Sweden)

Roxana HERGHILIGIU

2014-06-01

Full Text Available In the past 20 years operational and reputational risk has become more intriguing due to the public scandals of rogue tranding in banks like Barings Bank, Allied Irish Banks, Enron. The purpose of this study is to find the connections between operational risk and reputational risk. Our research shows that there may be a loss of reputation due to operational loss events. Moreover, every type of operational risk, from internal fraud, external fraud, legal and liability losses, processing errors, information security breaches, inappropriate business practice, physical security breaches conduct to a loss of reputation. The limitations of this paper are represented by the fact that do not have enough data to show the real impact of the reputation risk to the financial results of the European Banks.

Internet services for planning embedded generation connections

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-12-15

The required publication by distributed network operators (DNOs) of details of the current state of their network systems and future planned developments in the form of Long Term Development Statements (LTDS) are discussed. This project aims to increase the usefulness of the information in the LTDS by making it available on the internet, by transforming LTDSs into electronic format, and integrating LTDS information with geographical information in a single database. Services developed provide for data loading, data visualisation, initial assessment of connection opportunities, and reporting. The benefits of the services, and the demonstrated feasibility of publishing information concerning UK renewable generation sites are considered. The web address of the site is given.

Method of Geometric Connected Disk Cover Problem for UAV realy network deployment

Directory of Open Access Journals (Sweden)

Chuang Liu

2017-01-01

Full Text Available Aiming at the problem of the effective connectivity of a large number of mobile combat units in the future aeronautic swarm operation, this paper proposes an idea of using UAV(Unmanned Aerial Vehicle to build, and studies the deployment of the network. User coverage and network connectivity are important for a relay network planning which are studied separately in traditional ways. In order to effectively combine these two factors while the network’s survivability is taken into account. Firstly, the concept of node aggregation degree is proposed. Secondly, a performance evaluation parameter for UAV relay network is proposed based on node aggregation degree, then analyzes the lack of deterministic deployment and presents one a PSO (VFA-PSO deployment algorithm based on virtual force. Finally, compared with the existing algorithms, the validity and stability of the algorithm are verified. The experimental results show that the VFA-PSO algorithm can effectively improve the network coverage and the survivability of the network under the premise of ensuring the network connectivity, and has better deployment effect.

Optimization of an experimental hybrid microgrid operation: reliability and economic issues

OpenAIRE

Milo, Aitor; Gaztañaga, Haizea; Etxeberria Otadui, Ion; Bilbao, Endika; Rodríguez Cortés, Pedro

2009-01-01

In this paper a hybrid microgrid system, composed of RES (Renewable Energy System) and CHP (Combined Heat and Power) systems together with a battery based storage system is presented. The microgrid is accompanied by a centralized energy management system (CEMS) in order to optimize the microgrid operation both in grid-connected and in stand-alone modes. In grid-connected mode the optimization of the economic exploitation of the microgrid is privileged by applying optim...

Performance evaluation of a 2-mode PV grid connected system in Thailand -- Case study

Energy Technology Data Exchange (ETDEWEB)

Jivacate, C.; Mongconvorawan, S.; Sinratanapukdee, E.; Limsawatt, W. [Electricity Generating Authority of Thailand, Nontha Buri (Thailand)

1994-12-31

A PV grid connected system with small battery bank has been set up in a rural district, North Thailand in order to demonstrate a 2-mode operation concept. The objective is to gain experience on the PV grid connected concept without battery storage. However, due to the evening peak demand and a rather weak distribution grid which is typical in rural areas, small battery bank is still required to enable the maximum energy transfer to grid for the time being before moving fully to the no battery mode. The analyzed data seems to indicate possible performance improvement by re-arranging the number of PV modules and battery in the string.

5th International Conference on Operator Theory

CERN Document Server

Douglas, R; Nagy, B; Voiculescu, D; Arsene, Gr

1981-01-01

The first of the annual Operator Theory conferences in Ti­ mi~oara held four years ago was a meeting of operator theory spe­ cialists from the National Institute for Scientific and Techni­ cal Creation in Bucharest and from the University of Timi~oara. Since then, the participation to these conferences has greatly increased, by being attended first by operator theorists from allover the country and (since 1978) by an increasing number of foreign mathematicians. Thus the 1980 Conference can be regarded as a truly international Operator Theory meeting, fifteen coun­ tries being represented at it. These conferences are conceived as a means to promote the cooperation between specialists in all areas of Operator Theory. Among the main topics in 1980 were: dilation theory, invariant subspaces, connections with the theory of cX-algebras, subnormal operators, multidimensional functional calculus etc. Though not included in this volume, we would like to mention that in 1980 some special sessions concerning other f...

78 FR 61400 - Entergy Nuclear Operations, Inc., Pilgrim Nuclear Power Station, Issuance of Director's Decision

Science.gov (United States)

2013-10-03

... 40 years since their initial construction. The wires, and possibly the connections and splices inside conduits, are designed to operate properly only in a dry environment and are not designed to operate in a... construction. There are no existing methods to ensure operability, short of visual inspection or replacing...

Moral competence and brain connectivity: A resting-state fMRI study.

Science.gov (United States)

Jung, Wi Hoon; Prehn, Kristin; Fang, Zhuo; Korczykowski, Marc; Kable, Joseph W; Rao, Hengyi; Robertson, Diana C

2016-11-01

Moral competence (MC) refers to the ability to apply certain moral orientations in a consistent and differentiated manner when judging moral issues. People greatly differ in terms of MC, however, little is known about how these differences are implemented in the brain. To investigate this question, we used functional magnetic resonance imaging and examined resting-state functional connectivity (RSFC) in n=31 individuals with MC scores in the highest 15% of the population and n=33 individuals with MC scores in the lowest 15%, selected from a large sample of 730 Master of Business Administration (MBA) students. Compared to individuals with lower MC, individuals with higher MC showed greater amygdala-ventromedial prefrontal connectivity, which may reflect better ability to cope with emotional conflicts elicited by moral dilemmas. Moreover, individuals with higher MC showed less inter-network connectivity between the amygdalar and fronto-parietal networks, suggesting a more independent operation of these networks. Our findings provide novel insights into how individual differences in moral judgment are associated with RSFC in brain circuits related to emotion processing and cognitive control. Copyright © 2016 Elsevier Inc. All rights reserved.

Power control of a wind farm with active stall wind turbines and AC grid connection

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Sørensen, Poul; Iov, Florin

both the control on wind turbine level as well as the central control on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power production to the reference power ordered by the operators is assessed and discussed by means of simulations.......This paper describes the design of a centralised wind farm controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection. The overall aim of such controller is to enable the wind farms to provide the best grid support. The designed wind farm control involves...

Broadcasting collective operation contributions throughout a parallel computer

Science.gov (United States)

Faraj, Ahmad [Rochester, MN

2012-02-21

Methods, systems, and products are disclosed for broadcasting collective operation contributions throughout a parallel computer. The parallel computer includes a plurality of compute nodes connected together through a data communications network. Each compute node has a plurality of processors for use in collective parallel operations on the parallel computer. Broadcasting collective operation contributions throughout a parallel computer according to embodiments of the present invention includes: transmitting, by each processor on each compute node, that processor's collective operation contribution to the other processors on that compute node using intra-node communications; and transmitting on a designated network link, by each processor on each compute node according to a serial processor transmission sequence, that processor's collective operation contribution to the other processors on the other compute nodes using inter-node communications.

A Low-Voltage Ride-Through Technique for Grid-Connected Converters with Reduced Power Transistors Stress

DEFF Research Database (Denmark)

Chen, Hsin-Chih; Lee, Chia-Tse; Cheng, Po-Tai

2016-01-01

With more and more distributed energy resources being installed in the utility grid, grid operators start imposing the low-voltage ride-through requirement on such systems to remain grid-connected and inject reactive and/or active current to support grid voltage during fault conditions. This pape...

Dust-Tolerant Intelligent Electrical Connection System

Science.gov (United States)

Lewis, Mark; Dokos, Adam; Perotti, Jose; Calle, Carlos; Mueller, Robert; Bastin, Gary; Carlson, Jeffrey; Townsend, Ivan, III; Immer, Chirstopher; Medelius, Pedro

2012-01-01

Faults in wiring systems are a serious concern for the aerospace and aeronautic (commercial, military, and civilian) industries. Circuit failures and vehicle accidents have occurred and have been attributed to faulty wiring created by open and/or short circuits. Often, such circuit failures occur due to vibration during vehicle launch or operation. Therefore, developing non-intrusive fault-tolerant techniques is necessary to detect circuit faults and automatically route signals through alternate recovery paths while the vehicle or lunar surface systems equipment is in operation. Electrical connector concepts combining dust mitigation strategies and cable diagnostic technologies have significant application for lunar and Martian surface systems, as well as for dusty terrestrial applications. The dust-tolerant intelligent electrical connection system has several novel concepts and unique features. It combines intelligent cable diagnostics (health monitoring) and automatic circuit routing capabilities into a dust-tolerant electrical umbilical. It retrofits a clamshell protective dust cover to an existing connector for reduced gravity operation, and features a universal connector housing with three styles of dust protection: inverted cap, rotating cap, and clamshell. It uses a self-healing membrane as a dust barrier for electrical connectors where required, while also combining lotus leaf technology for applications where a dust-resistant coating providing low surface tension is needed to mitigate Van der Waals forces, thereby disallowing dust particle adhesion to connector surfaces. It also permits using a ruggedized iris mechanism with an embedded electrodynamic dust shield as a dust barrier for electrical connectors where required.

Dynamic modelling of VSC-HVDC for connection of offshore wind farms

DEFF Research Database (Denmark)

Rios, Bardo; Garcia-Valle, Rodrigo

2011-01-01

A VSC-HVDC (Voltage Source Converter – High Voltage Direct Current) dynamic model with a set of control strategies is developed in DIgSILENT Power-Factory with the objective of analyzing the converter’s operating capability for grid support during grid faults. The investigation is carried out based...... on a 165 MW offshore wind farm with induction generators and a Low Voltage Ride-Through solution of the offshore wind turbines and Static Voltage Compensator units in the point of connection with a grid represented by a reduced four-generator power grid model. VSC-HVDC promises to be a reliable alternative...... solution for interconnection with off-shore wind farms as they become larger, with a higher installed power capacity, increased number of wind turbines, and geographically situated at larger distances from suitable connection points in the transmission grids....

Two-stage single-phase grid-connected photovoltaic system with reduced complexity

Science.gov (United States)

da Silva, Cintia S.; Motta, Filipe R.; Tofoli, Fernando L.

2011-06-01

This article presents a grid-connected photovoltaic (PV) system using the classical DC-DC buck converter, which is responsible for stepping down the resulting voltage from several series-connected panels. Besides, the structure provides high power factor operation by injecting a quasi-sinusoidal current into the grid, with near no displacement in relation to the line voltage at the point of common coupling among the PV system and the loads. A CSI employing thyristors is cascaded with the DC-DC stage so that AC voltage results. The inverter output voltage level is adjusted by using a low-frequency transformer, which also provides galvanic isolation. The proposed system is described as mathematical approach and design guidelines are presented, providing an overview of the topology. An experimental prototype is also implemented, and relevant results to validate the proposal are discussed.

Flocking of Second-Order Multiagent Systems With Connectivity Preservation Based on Algebraic Connectivity Estimation.

Science.gov (United States)

Fang, Hao; Wei, Yue; Chen, Jie; Xin, Bin

2017-04-01

The problem of flocking of second-order multiagent systems with connectivity preservation is investigated in this paper. First, for estimating the algebraic connectivity as well as the corresponding eigenvector, a new decentralized inverse power iteration scheme is formulated. Then, based on the estimation of the algebraic connectivity, a set of distributed gradient-based flocking control protocols is built with a new class of generalized hybrid potential fields which could guarantee collision avoidance, desired distance stabilization, and the connectivity of the underlying communication network simultaneously. What is important is that the proposed control scheme allows the existing edges to be broken without violation of connectivity constraints, and thus yields more flexibility of motions and reduces the communication cost for the multiagent system. In the end, nontrivial comparative simulations and experimental results are performed to demonstrate the effectiveness of the theoretical results and highlight the advantages of the proposed estimation scheme and control algorithm.

Characterization of wastewater treatment by two microbial fuel cells in continuous flow operation.

Science.gov (United States)

Kubota, Keiichi; Watanabe, Tomohide; Yamaguchi, Takashi; Syutsubo, Kazuaki

2016-01-01

A two serially connected single-chamber microbial fuel cell (MFC) was applied to the treatment of diluted molasses wastewater in a continuous operation mode. In addition, the effect of series and parallel connection between the anodes and the cathode on power generation was investigated experimentally. The two serially connected MFC process achieved 79.8% of chemical oxygen demand removal and 11.6% of Coulombic efficiency when the hydraulic retention time of the whole process was 26 h. The power densities were 0.54, 0.34 and 0.40 W m(-3) when electrodes were in individual connection, serial connection and parallel connection modes, respectively. A high open circuit voltage was obtained in the serial connection. Power density decreased at low organic loading rates (OLR) due to the shortage of organic matter. Power generation efficiency tended to decrease as a result of enhancement of methane fermentation at high OLRs. Therefore, high power density and efficiency can be achieved by using a suitable OLR range.

Operation control device for nuclear power plants

International Nuclear Information System (INIS)

Suto, Osamu.

1982-01-01

Purpose: To render the controlling functions of a central control console more centralized by constituting the operation controls for a nuclear power plant with computer systems having substantially independent functions such as those of plant monitor controls, reactor monitor management and CRT display and decreasing interactions between each of the systems. Constitution: An input/output device for the input of process data for a nuclear power plant and indication data for a plant control console is connected to a plant supervisory and control computer system and a display computer system, the plant supervisory control computer system and a reactor and management computer system are connected with a CRT display control device, a printer and a CRT display input/output device, and the display computer system is connected with the CRT display control device and the CRT display unit on the central control console, whereby process input can be processed and displayed at high speed. (Yoshino, Y.)

Directional connectivity in hydrology and ecology

Science.gov (United States)

Larsen, Laurel G.; Choi, Jungyill; Nungesser, Martha K.; Harvey, Judson W.

2012-01-01

Quantifying hydrologic and ecological connectivity has contributed to understanding transport and dispersal processes and assessing ecosystem degradation or restoration potential. However, there has been little synthesis across disciplines. The growing field of ecohydrology and recent recognition that loss of hydrologic connectivity is leading to a global decline in biodiversity underscore the need for a unified connectivity concept. One outstanding need is a way to quantify directional connectivity that is consistent, robust to variations in sampling, and transferable across scales or environmental settings. Understanding connectivity in a particular direction (e.g., streamwise, along or across gradient, between sources and sinks, along cardinal directions) provides critical information for predicting contaminant transport, planning conservation corridor design, and understanding how landscapes or hydroscapes respond to directional forces like wind or water flow. Here we synthesize progress on quantifying connectivity and develop a new strategy for evaluating directional connectivity that benefits from use of graph theory in ecology and percolation theory in hydrology. The directional connectivity index (DCI) is a graph-theory based, multiscale metric that is generalizable to a range of different structural and functional connectivity applications. It exhibits minimal sensitivity to image rotation or resolution within a given range and responds intuitively to progressive, unidirectional change. Further, it is linearly related to the integral connectivity scale length—a metric common in hydrology that correlates well with actual fluxes—but is less computationally challenging and more readily comparable across different landscapes. Connectivity-orientation curves (i.e., directional connectivity computed over a range of headings) provide a quantitative, information-dense representation of environmental structure that can be used for comparison or detection of

Directional connectivity in hydrology and ecology.

Science.gov (United States)

Larsen, Laurel G; Choi, Jungyill; Nungesser, Martha K; Harvey, Judson W

2012-12-01

Quantifying hydrologic and ecological connectivity has contributed to understanding transport and dispersal processes and assessing ecosystem degradation or restoration potential. However, there has been little synthesis across disciplines. The growing field of ecohydrology and recent recognition that loss of hydrologic connectivity is leading to a global decline in biodiversity underscore the need for a unified connectivity concept. One outstanding need is a way to quantify directional connectivity that is consistent, robust to variations in sampling, and transferable across scales or environmental settings. Understanding connectivity in a particular direction (e.g., streamwise, along or across gradient, between sources and sinks, along cardinal directions) provides critical information for predicting contaminant transport, planning conservation corridor design, and understanding how landscapes or hydroscapes respond to directional forces like wind or water flow. Here we synthesize progress on quantifying connectivity and develop a new strategy for evaluating directional connectivity that benefits from use of graph theory in ecology and percolation theory in hydrology. The directional connectivity index (DCI) is a graph-theory based, multiscale metric that is generalizable to a range of different structural and functional connectivity applications. It exhibits minimal sensitivity to image rotation or resolution within a given range and responds intuitively to progressive, unidirectional change. Further, it is linearly related to the integral connectivity scale length--a metric common in hydrology that correlates well with actual fluxes--but is less computationally challenging and more readily comparable across different landscapes. Connectivity-orientation curves (i.e., directional connectivity computed over a range of headings) provide a quantitative, information-dense representation of environmental structure that can be used for comparison or detection of

Processing module operating methods, processing modules, and communications systems

Science.gov (United States)

McCown, Steven Harvey; Derr, Kurt W.; Moore, Troy

2014-09-09

A processing module operating method includes using a processing module physically connected to a wireless communications device, requesting that the wireless communications device retrieve encrypted code from a web site and receiving the encrypted code from the wireless communications device. The wireless communications device is unable to decrypt the encrypted code. The method further includes using the processing module, decrypting the encrypted code, executing the decrypted code, and preventing the wireless communications device from accessing the decrypted code. Another processing module operating method includes using a processing module physically connected to a host device, executing an application within the processing module, allowing the application to exchange user interaction data communicated using a user interface of the host device with the host device, and allowing the application to use the host device as a communications device for exchanging information with a remote device distinct from the host device.

Graph Theory Roots of Spatial Operators for Kinematics and Dynamics

Science.gov (United States)

Jain, Abhinandan

2011-01-01

Spatial operators have been used to analyze the dynamics of robotic multibody systems and to develop novel computational dynamics algorithms. Mass matrix factorization, inversion, diagonalization, and linearization are among several new insights obtained using such operators. While initially developed for serial rigid body manipulators, the spatial operators and the related mathematical analysis have been shown to extend very broadly including to tree and closed topology systems, to systems with flexible joints, links, etc. This work uses concepts from graph theory to explore the mathematical foundations of spatial operators. The goal is to study and characterize the properties of the spatial operators at an abstract level so that they can be applied to a broader range of dynamics problems. The rich mathematical properties of the kinematics and dynamics of robotic multibody systems has been an area of strong research interest for several decades. These properties are important to understand the inherent physical behavior of systems, for stability and control analysis, for the development of computational algorithms, and for model development of faithful models. Recurring patterns in spatial operators leads one to ask the more abstract question about the properties and characteristics of spatial operators that make them so broadly applicable. The idea is to step back from the specific application systems, and understand more deeply the generic requirements and properties of spatial operators, so that the insights and techniques are readily available across different kinematics and dynamics problems. In this work, techniques from graph theory were used to explore the abstract basis for the spatial operators. The close relationship between the mathematical properties of adjacency matrices for graphs and those of spatial operators and their kernels were established. The connections hold across very basic requirements on the system topology, the nature of the component

Privacy and the Connected Society

DEFF Research Database (Denmark)

Sørensen, Lene Tolstrup; Khajuria, Samant; Skouby, Knud Erik

The Vision of the 5G enabled connected society is highly based on the evolution and implementation of Internet of Things. This involves, amongst others, a significant raise in devices, sensors and communication in pervasive interconnections as well as cooperation amongst devices and entities across...... the society. Enabling the vision of the connected society, researchers point in the direction of security and privacy as areas to challenge the vision. By use of the Internet of Things reference model as well as the vision of the connected society, this paper identifies privacy of the individual with respect...... to three selected areas: Shopping, connected cars and online gaming. The paper concludes that privacy is a complexity within the connected society vision and that thee is a need for more privacy use cases to shed light on the challenge....

Social media and (dis)connectivity

DEFF Research Database (Denmark)

Tække, Jesper

The paper discuss the relation between media of communication and societal (dis)connectivity. The question is how communication media provide society with different possibilities for (dis)connectivity in different historical media societies. The paper draws on Luhmann’s theory of social systems...... for social systems to develop structures with new forms of communicative connections. Even though society only is possible because of communication media and gets new possibilities for the formation of new structures providing it with new connection possibilities, in the beginning a new communication medium....... In the present society we also see signs of new dis-connectivity, i.e. fake news, political polarization, and economic and democratic inequality. In the final section the paper analyse such problems triggered by digital media. Also the paper point out some new possibilities triggered by the acquisition of social...

Modeling and Control of VSC based DC Connection for Active Stall Wind Farms to Grid

DEFF Research Database (Denmark)

Iov, Florin; Sorensen, Poul; Hansen, Anca-Daniela

2005-01-01

Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Therefore the power system becomes more vulnerable and dependent on the wind energy production. At the same time requirements that focus on the influence of the farms on the grid stability and power...... quality, and on the control capabilities of wind farms have already been established. The main trends of modem wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics...... the control capabilities of these wind turbines/farms are extended and thus the grid requirements are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid does not have such control capabilities. They produce maximum possible power...

Modelling and Control of VSC based DC Connection for Active Stall Wind Farms to Grid

DEFF Research Database (Denmark)

Iov, Florin; Sørensen, Poul; Hansen, Anca Daniela

2006-01-01

Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Therefore the power system becomes more vulnerable and dependent on the wind energy production. At the same time requirements that focus on the influence of the farms on the grid stability and power...... quality, and on the control capabilities of wind farms have already been established. The main trends of modern wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics...... the control capabilities of these wind turbines/farms are extended and thus the grid requirements are fulfilled.  However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid does not have such control capabilities. They produce maximum possible power...

Research on Experiment of Islanding Protection Device of Grid-connected Photovoltaic System Based on RTDS

Science.gov (United States)

Zhou, Ning; Yang, Jia; Cheng, Zheng; Chen, Bo; Su, Yong Chun; Shu, Zhan; Zou, Jin

2017-06-01

Solar photovoltaic power generation is the power generation using solar cell module converting sunlight into DC electric energy. In the paper an equivalent model of solar photovoltaic power generation system is built in RTDS. The main circuit structure of the two-stage PV grid-connected system consists of the DC-DC, DC-AC circuit. The MPPT (Maximum Power Point Tracking) control of the PV array is controlled by adjusting the duty ratio of the DC-DC circuit. The proposed control strategy of constant voltage/constant reactive power (V/Q) control is successfully implemented grid-connected control of the inverter when grid-connected operation. The closed-loop experiment of islanding protection device of photovoltaic power plant on RTDS, verifies the correctness of the simulation model, and the experimental verification can be applied to this type of device.

Life Cycle Assessment of Connected and Automated Vehicles: Sensing and Computing Subsystem and Vehicle Level Effects.

Science.gov (United States)

Gawron, James H; Keoleian, Gregory A; De Kleine, Robert D; Wallington, Timothy J; Kim, Hyung Chul

2018-03-06

Although recent studies of connected and automated vehicles (CAVs) have begun to explore the potential energy and greenhouse gas (GHG) emission impacts from an operational perspective, little is known about how the full life cycle of the vehicle will be impacted. We report the results of a life cycle assessment (LCA) of Level 4 CAV sensing and computing subsystems integrated into internal combustion engine vehicle (ICEV) and battery electric vehicle (BEV) platforms. The results indicate that CAV subsystems could increase vehicle primary energy use and GHG emissions by 3-20% due to increases in power consumption, weight, drag, and data transmission. However, when potential operational effects of CAVs are included (e.g., eco-driving, platooning, and intersection connectivity), the net result is up to a 9% reduction in energy and GHG emissions in the base case. Overall, this study highlights opportunities where CAVs can improve net energy and environmental performance.

[Connective tissue and inflammation].

Science.gov (United States)

Jakab, Lajos

2014-03-23

The author summarizes the structure of the connective tissues, the increasing motion of the constituents, which determine the role in establishing the structure and function of that. The structure and function of the connective tissue are related to each other in the resting as well as inflammatory states. It is emphasized that cellular events in the connective tissue are part of the defence of the organism, the localisation of the damage and, if possible, the maintenance of restitutio ad integrum. The organism responds to damage with inflammation, the non specific immune response, as well as specific, adaptive immunity. These processes are located in the connective tissue. Sterile and pathogenic inflammation are relatively similar processes, but inevitable differences are present, too. Sialic acids and glycoproteins containing sialic acids have important roles, and the role of Siglecs is also highlighted. Also, similarities and differences in damages caused by pathogens and sterile agents are briefly summarized. In addition, the roles of adhesion molecules linked to each other, and the whole event of inflammatory processes are presented. When considering practical consequences it is stressed that the structure (building up) of the organism and the defending function of inflammation both have fundamental importance. Inflammation has a crucial role in maintaining the integrity and the unimpaired somato-psychological state of the organism. Thus, inflammation serves as a tool of organism identical with the natural immune response, inseparably connected with the specific, adaptive immune response. The main events of the inflammatory processes take place in the connective tissue.

A Desktop Screen Sharing System based on Various Connection Methods

Science.gov (United States)

Negishi, Yuya; Kawaguchi, Nobuo

Recently it became very common to use information devices such as PCs during presentations and discussions. In these situations, a need arises for techniques that allow a smooth switch of presenters without changing cables, or an easy screen sharing in case of remote videoconferences. In this paper, we propose a desktop screen sharing system that can be used for such purposes and situations. For that, we designed an automatic control of connections in the VNC system that can be operated remotely over the network. We also suggested an interface that assigns a role such as “Screen sender" or “Screen receiver" to each terminal. In the proposed system, while sharing a screen between multiple terminals, one can easily display and browse the screen without having to understand how the others are connected. We also implemented a “role card" using contactless IC card, where roles are assigned only by placing the card in the IC reader.

Operation of the Pierre Auger Observatory

International Nuclear Information System (INIS)

Rodriguez Martino, Julio

2011-01-01

While the work to make data acquisition fully automatic continues, both the Fluorescence Detectors and the Surface Detectors of the Pierre Auger Observatory need some kind of attention from the local staff. In the first case, the telescopes are operated and monitored during the moonless periods. The ground array only needs monitoring, but the larger number of stations implies more variables to consider. AugerAccess (a high speed internet connection) will give the possibility of operating and monitoring the observatory from any place in the world. This arises questions about secure access, better control software and alarms. Solutions are already being tested and improved.

ASEAN grid-connected biomass residues fired cogeneration plants

International Nuclear Information System (INIS)

Adnan, M.F.; Alias, R.

2006-01-01

Energy supply is one of the major concerns in the world. With uncertainty in the main oil suppliers, the oil price is expected to remain high due to continuous demand from the world. Since oil is mostly used for electricity and transportation, its shortage would cause major disruptions in our daily activities. Thus to counter this scenario and faster depletion of fossil fuel resources, various measures have been taken to find alternative source of energy such as renewable energy. One of the renewable energy sources is from biomass residues which is aplenty particularly in ASEAN. Through one of the collaboration programme between ASEAN and EC which is The EC-ASEAN Cogeneration Programme, a number of Full-Scale Demonstration Projects (FSDP) using biomass residues have been commissioned and implemented successfully. Four of the FSDPs in Thailand and Malaysia are connected to the grid. These projects have been operating very well and since the fuel is commonly available in this ASEAN region, duplication should not be a problem. Thus, this paper would highlight the success stories in implementing biomass residues grid connected project while enhancing cooperation between ASEAN and EC. (Author)

Voltage Harmonic Compensation of a Microgrid Operating in Islanded and Grid-Connected Modes

DEFF Research Database (Denmark)

Savaghebi, Mehdi; Jalilian, Alireza; Vasquez, Juan C.

2011-01-01

In this paper, a method for voltage harmonic compensation in a microgrid operating in islanded and gridconnected modes is presented. Harmonic compensation is done through proper control of distributed generators (DGs) interface converters. In order to achieve proper sharing of the compensation...

46 CFR 167.30-10 - Special operating requirements.

Science.gov (United States)

2010-10-01

..., (3) Within or on the boundaries of fuel tanks; or, (4) To pipe lines, heating coils, pumps, fittings, or other appurtenances connected to such cargo or fuel tanks. (c) Such inspections shall be made and... SCHOOL SHIPS Repairs or Alterations § 167.30-10 Special operating requirements. Inspection and testing...

Modeling and power system stability of VSC-HVDC systems for grid-connection of large offshore windfarms

Energy Technology Data Exchange (ETDEWEB)

Xue Yijing [Vestas China, Beijing (China); Akhmatov, Vladislav [Technical Univ. of Denmark, Lyngby (Denmark). Centre for Electric Technology

2009-07-01

Utilization of Voltage Source Converter (VSC) - High Voltage Direct Current (HVDC) systems for grid-connection of large offshore windfarms becomes relevant as installed power capacities as well as distances to the connection points of on-land transmission systems increase. At the same time, the grid code requirements of the Transmission System Operators (TSO), including ancillary system services and Low-Voltage Fault-Ride-Through (LVFRT) capability of large offshore windfarms, become more demanding. This paper presents a general-level model of and a LVFRT solution for a VSC-HVDC system for grid-connection of large offshore windfarms. The VSC-HVDC model is implemented using a general approach of independent control of active and reactive power in normal operations. The on-land VSC inverter, i.e. a grid-side inverter, provides voltage support to the transmission system and comprises a LVFRT solution in short-circuit faults. The presented model, LVFRT solution and impact on the system stability are investigated as a case study of a 1,000 MW offshore windfarm grid-connected through a VSC-HVDC system. The investigation is carried out on a model of the west Danish, with some elements of the north German, 400 kV, 220 kV and 150 kV transmission systems stage 2005-2006 using the DIgSILENT PowerFactory simulation program. In the investigation, a thermal power plant just south to the Danish border has been substituted by this 1,000 MW offshore windfarm utilizing the VSC-HVDC system. The investigation has shown that the substitution of a thermal power plant by a VSC-HVDC connected offshore windfarm should not have any negative impact on the short-term stability of the west Danish transmission system. The investigation should be repeated applying updated system model stages and offshore wind power commissioning schedules in the North and Baltic Seas. (orig.)

Complex networks of functional connectivity in a wetland reconnected to its floodplain

Science.gov (United States)

Larsen, Laurel G.; Newman, Susan; Saunders, Colin; Harvey, Judson

2017-01-01

Disturbances such as fire or flood, in addition to changing the local magnitude of ecological, hydrological, or biogeochemical processes, can also change their functional connectivity—how those processes interact in space. Complex networks offer promise for quantifying functional connectivity in watersheds. The approach resolves connections between nodes in space based on statistical similarities in perturbation signals (derived from solute time series) and is sensitive to a wider range of timescales than traditional mass-balance modeling. We use this approach to test hypotheses about how fire and flood impact ecological and biogeochemical dynamics in a wetland (Everglades, FL, USA) that was reconnected to its floodplain. Reintroduction of flow pulses after decades of separation by levees fundamentally reconfigured functional connectivity networks. The most pronounced expansion was that of the calcium network, which reflects periphyton dynamics and may represent an indirect influence of elevated nutrients, despite the comparatively smaller observed expansion of phosphorus networks. With respect to several solutes, periphyton acted as a “biotic filter,” shifting perturbations in water-quality signals to different timescales through slow but persistent transformations of the biotic community. The complex-networks approach also revealed portions of the landscape that operate in fundamentally different regimes with respect to dissolved oxygen, separated by a threshold in flow velocity of 1.2 cm/s, and suggested that complete removal of canals may be needed to restore connectivity with respect to biogeochemical processes. Fire reconfigured functional connectivity networks in a manner that reflected localized burn severity, but had a larger effect on the magnitude of solute concentrations.

Comparison of Standards and Technical Requirements of Grid-Connected Wind Power Plants in China and the United States

Energy Technology Data Exchange (ETDEWEB)

Gao, David Wenzhong [Alternative Power Innovations, LLC; Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, Mackay [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wang, Weisheng [China Electric Power Research Inst. (China)

2016-09-01

The rapid deployment of wind power has made grid integration and operational issues focal points in industry discussions and research. Compliance with grid connection standards for wind power plants (WPPs) is crucial to ensuring the reliable and stable operation of the electric power grid. This report compares the standards for grid-connected WPPs in China to those in the United States to facilitate further improvements in wind power standards and enhance the development of wind power equipment. Detailed analyses of power quality, low-voltage ride-through capability, active power control, reactive power control, voltage control, and wind power forecasting are provided to enhance the understanding of grid codes in the two largest markets of wind power. This study compares WPP interconnection standards and technical requirements in China to those in the United States.

Grid-connected solar electricity in France : the example of Martinique, a French overseas department

Energy Technology Data Exchange (ETDEWEB)

Melle, Y. [Tenesol (France)

2006-07-01

Tenesol has specialized in photovoltaic (PV) solar energy since 1983 with experience in grid connections, professional applications, decentralized rural electrification and solar pumping. The company's operations include the manufacture of solar panels, system design and turnkey installations backed by a comprehensive after sales service through a global network of subsidiaries. Half of Tenesol's group shareholdings belong to Electricite de France and half belong to Total. The 2 specialized subsidiaries of Tenesol are Tenesa Manufacturing and Tenesol Technologies. This presentation focused Tenesol's operations in Martinique and its financial environment of grid-connected photovoltaics. It presented Tenesol's approach for technical and economic validation of roof suitability in terms of the disc orientation of PV panels. The key figures of installing a 300 square metre 40 kWp PV system were presented along with photographs of installations in Martinique. The installations have a total installed capacity of 2.5 MWp and an annual solar electricity production of 3,375,000 kWhs, resulting in a reduction of 3,000 tons of carbon dioxide annually. figs.

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

International Nuclear Information System (INIS)