Coordination between Fault-Ride-Through Capability and Overcurrent Protection of DFIG Generatorsfor Wind Farms

DEFF Research Database (Denmark)

Bak-Jensen, Birgitte; Kawady, Tamer A.; Abdel-Rahman, Mansour H.

2009-01-01

Due to the increasing penetration of wind farms in power systems, stability issues arise strongly for power system operation. Doubly-Fed Induction Generators (DFIG) are charac-terized with some unique features during normal/abnormal op-erating conditions as compared with singly-fed ones. Fault ri...... on protective relaying coordination in wind farms.......-Through (FRT) mainly aims to delay a disconnecting of the DFIG units during grid faults for a possible time to restore the system stability if the fault is cleared within a permissible time. This strategy may, however, affect the performance of related protective elements during fault periods. In this paper......, the Coor-dination between Fault Ride-Through Capability and Overcur-rent Protection of DFIG Wind Generators in MV Networks is in-vestigated. Simulation test cases using MATLAB-Simulink are implemented on a 345-MW wind farm in AL-Zaafarana, Egypt. The simulation results show the influence of FRT capability...

Fault ride-through capability of DFIG wind turbines

Energy Technology Data Exchange (ETDEWEB)

Hansen, Anca D. [Risoe National Laboratory, Wind Energy Department, P.O. Box 49, DK-4000 Roskilde (Denmark); Michalke, Gabriele [Darmstadt University, Institute for Electrical Power Systems, Landgraf-Georg-Strasse 4, 64283 Darmstadt (Germany)

2007-07-15

This paper concentrates on the fault ride-through capability of doubly fed induction generator (DFIG) wind turbines. The main attention in the paper is, therefore, drawn to the control of the DFIG wind turbine and of its power converter and to the ability to protect itself without disconnection during grid faults. The paper provides also an overview on the interaction between variable-speed DFIG wind turbines and the power system subjected to disturbances, such as short circuit faults. The dynamic model of DFIG wind turbine includes models for both mechanical components as well as for all electrical components, controllers and for the protection device of DFIG necessary during grid faults. The viewpoint of the paper is to carry out different simulations to provide insight and understanding of the grid fault impact on both DFIG wind turbines and on the power system itself. The dynamic behaviour of DFIG wind turbines during grid faults is simulated and assessed by using a transmission power system generic model developed and delivered by the Danish Transmission System Operator Energinet.dk in the power system simulation toolbox PowerFactory DIgSILENT. The data for the wind turbines are not linked to a specific manufacturer, but are representative for the turbine and generator type used in variable-speed DFIG wind turbines with pitch control. (author)

A Comprehensive Review of Low-Voltage-Ride-Through Methods for Fixed-Speed Wind Power Generators

DEFF Research Database (Denmark)

Moghadasi, Amirhasan; Sarwat, Arif; Guerrero, Josep M.

2016-01-01

This paper presents a comprehensive review of various techniques employed to enhance the low voltage ride through (LVRT) capability of the fixed-speed induction generators (FSIGs)-based wind turbines (WTs), which has a non-negligible 20% contribution of the existing wind energy in the world...

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.

An Innovative Control Strategy to Improve the Fault Ride-Through Capability of DFIGs Based on Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Vandai Le

2016-01-01

Full Text Available An innovative control strategy is proposed for enhancing the low voltage ride-through (LVRT capability of a doubly fed induction generator based on wind energy conversion systems (DFIG-WECS. Within the proposed control method, the current control loops of the rotor side converter (RSC are developed based on passivity theory. The control scheme for the grid side converter (GSC is designed based on a two-term approach to keep the DC-link voltage close to a given value. The first term based on the maximal voltage of GSC is introduced in the GSC control loops as a reference reactive current. The second one reflecting the instantaneous unbalanced power flow between the RSC and GSC is also introduced in the GSC control loops as a disturbance considering the instantaneous power of the grid filter to compensate the instantaneous rotor power. The effectiveness of the proposed control strategy is verified via time domain simulation of a 2.0 MW-575 V DFIG-WECS using PSCAD/EMTP. Simulation results show that the control of the DFIG with the proposed approach can improve the LVRT capability better than with the conventional one.

Proportional-Resonant Control of Doubly-Fed Induction Generator Wind Turbines for Low-Voltage Ride-Through Enhancement

Directory of Open Access Journals (Sweden)

Zhan-Feng Song

2012-11-01

Full Text Available A novel control strategy is proposed in this paper for the rotor side converter (RSC of doubly-fed induction generator (DFIG-based wind power generation systems. It is supposed to enhance the low-voltage ride-through (LVRT capability of DFIGs during great-level grid voltage dips. The strategy consists of a proportional-resonant (PR controller and auxiliary PR controllers. The auxiliary controllers compensate the output voltage of the RSC in case of grid faults, thus limiting the rotor inrush current of DFIG and meeting the requirements of LVRT. Sequential-component decompositions of current are not required in the control system to improve the response of system. Since the resonant compensator is a double-side integrator, the auxiliary controllers can be simplified through coordinate transformation. The feasibility of the control strategy is validated by simulation on a 1.5 MW wind-turbine driven DFIG system. The impact of the RSC converter voltage rating on the LVRT capability of DFIG is investigated. Meanwhile, the influence of angular frequency detection and control parameters are also discussed. Compared with traditional vector control schemes based on PI current controllers, the presented control strategy effectively suppress rotor current and reduce oscillations of DFIG power and torque under grid faults.

Improved fault ride through capability of DFIG based wind turbines using synchronous reference frame control based dynamic voltage restorer.

Science.gov (United States)

Rini Ann Jerin, A; Kaliannan, Palanisamy; Subramaniam, Umashankar

2017-09-01

Fault ride through (FRT) capability in wind turbines to maintain the grid stability during faults has become mandatory with the increasing grid penetration of wind energy. Doubly fed induction generator based wind turbine (DFIG-WT) is the most popularly utilized type of generator but highly susceptible to the voltage disturbances in grid. Dynamic voltage restorer (DVR) based external FRT capability improvement is considered. Since DVR is capable of providing fast voltage sag mitigation during faults and can maintain the nominal operating conditions for DFIG-WT. The effectiveness of the DVR using Synchronous reference frame (SRF) control is investigated for FRT capability in DFIG-WT during both balanced and unbalanced fault conditions. The operation of DVR is confirmed using time-domain simulation in MATLAB/Simulink using 1.5MW DFIG-WT. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Review of the system compatibility and ride-through options for AC and DC drives including multilevel inverters

Energy Technology Data Exchange (ETDEWEB)

Jouanne, A. von [Power Electronics Lab. - Elect. and Compt. Engineering Dept. - Oregon State Univ., Corvallis, OR (United States); Ben Banerjee, B. [Electric Power Research Inst. - Power Electronics, Energy Delivery, Palo Alto, CA (United States)

2000-07-01

Adjustable speed drive (ASD) compatibility and ride-through issues have caused increased concerns due to the susceptibility of AC and DC drives to power disturbances, and the costly results of process disruptions. These losses can be avoided for critical production processes by using ASDs with ride-through capabilities. This paper assesses industrial ride-through requirements and application issues for AC and DC drives, including medium voltage (2300/4160 V) multi-level inverter topologies. Ride-through alternatives are evaluated based on design, implementation and cost considerations in order to determine the most suitable solutions for various kVA ratings and time duration requirements. (orig.)

Supercapacitor energy storage system for fault ride-through of a DFIG wind generation system

International Nuclear Information System (INIS)

Rahim, A.H.M.A.; Nowicki, E.P.

2012-01-01

Highlights: ► A detailed dynamic model of a DFIG is developed to study the low voltage ride-through phenomenon. ► A supercapacitor-STATCOM energy storage system is employed. ► Decoupled real and reactive power control strategies implemented on the system. ► The proposed controller show extremely good transient behavior following low voltage conditions. - Abstract: The doubly fed induction generators (DFIGs) are preferred over other variable speed generators because of their advantages in terms of economy and control. One of the problems associated with high wind power penetration DFIG systems, however, is the inability of their converters to work properly under extreme low voltage conditions. This article presents a decoupled P–Q control strategy of a supercapacitor energy storage system, interfaced through a STATCOM, for low voltage ride through as well as damping enhancement of the DFIG system. The STATCOM meets the reactive power need under the depressed voltage condition, while the supercapacitor caters to the real power unbalance. An extensive dynamic model of the DFIG system including a supercapacitor DC–DC buck–boost converter and the STATCOM circuit has been developed. The fault ride-thorough capability of the generator has been investigated for a severe symmetrical three-phase to ground fault on the grid bus. Simulation results suggest that the proposed decoupled control of the supercapacitor STATCOM control strategy can help the DFIG ride through extreme low voltage conditions for significant duration. The proposed control strategy also damps the electromechanical transients, and thus quickly restores normal operation of the converters.

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

DEFF Research Database (Denmark)

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

2017-01-01

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

Evaluation of the Ride-Through Capability of an Active-Front-End Adjustable Speed Drive under Real Grid Conditions

DEFF Research Database (Denmark)

Liserre, Marco; Klumpner, Christian; Blaabjerg, Frede

2004-01-01

Better quality of the input currents, unity power factor and regenerative capability are not the only benefits of equipping an Adjustable Speed Drive (ASD) with an active front-end-stage. Controlling the power inflow may enable also the reduction of the dc-link energy storage, which will then lead...... to the replacement of the electrolytic capacitors with film capacitors, which have lower energy density meaning that the volume is similar, but will increase the ASD lifetime. In these circumstances, operation under unbalanced and distorted supply voltage as well as high dynamic operation of the ASD makes...... the control task more challenging. The aim of this paper is to investigate the ride-through capability of an ASD with active front-end under real grid conditions and in view of the minimum dc-link storage. Experiments validate the theoretical analysis....

Distributed Low Voltage Ride-Through Operation of Power Converters in Grid-Connected Microgrids under Voltage Sags

DEFF Research Database (Denmark)

Zhao, Xin; Meng, Lexuan; Dragicevic, Tomislav

2015-01-01

it can make the MG a contributor in smooth ride through the faults. In this paper, a reactive power support strategy using droop controlled converters is proposed to aid MG riding through three phase symmetrical voltage sags. In such a case, the MGs should inject reactive power to the grid to boost...... the voltage in all phases at AC common bus. However, since the line admittances from each converter to point of common coupling (PCC) are not identical, the injected reactive power may not be equally shared. In order to achieve low voltage ride through (LVRT) capability along with a good power sharing...

A static VAR compensator model for improved ride-through capability of wind farms

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, V.; Soebrink, K.

2004-12-01

Dynamic reactive compensation is associated with reactive power and voltage control of induction generator based wind turbines. With regard to wind power, application areas of dynamic reactive compensation can be improvement of the power quality and the voltage stability, the control of the reactive power exchange between the wind farm and the power grid in the wind farm connection point as well as improvement of the ride-through capability of the wind farm. This article presents a model of a Static VAR Compensator (SVC) with dynamic generic control that is a kind of dynamic reactive compensation device. The term 'generic' implies that the model is general and must cover a variety of the SVC units and their specific controls from different manufacturers. The SVC model with dynamic generic control is implemented by Eltra in the simulation tool Powerfactory and validated from the SVC model in the tool PSCAD/EMTDC. Implementation in the tool Powerfactory makes it possible to apply the SVC model with dynamic generic control in investigations of power system stability with regard to establishment of large wind farms without restrictions on the model size of the power grid. (Author)

Study on Application of New Approach of Fault Current Limiters in Fault Ride through Capability Improvement of DFIG Based Wind Turbine

DEFF Research Database (Denmark)

Naderi, Seyed Behzad; Davari, Pooya; Zhou, Dao

2018-01-01

Due to salient advantages, Doubly-Fed Induction Generator (DFIG) has more application in power network compared to Fixed Speed Wind Turbine. Because of employing back-to-back converters, one of the important studies regarding new grid code requirements is Fault Ride-Through (FRT) capability....... The proposed FCL can insert a controllable resistance in fault current pass to not only restrict fault current level and compensate voltage sag in the stator but also consume pre-fault output active power of the DFIG regarding wind speed variation. Simulation results and analytics are presented to prove...

Fault Ride Through Enhancement of VSC‐HVDC Connected Offshore Wind Power Plants

DEFF Research Database (Denmark)

Sharma, Ranjan; Wu, Qiuwei; Jensen, Kim Høj

2018-01-01

the model of a VSC‐HVDC‐connected offshore wind power plant (WPP) with an external grid. It proposes a feedforward DC voltage control based FRT technique to control the AC voltage at the WPP collector network during grid‐side faults. Time‐domain simulations have been used to verify the efficacy......Voltage source converter‐high voltage direct current (VSC‐HVDC) connections have become a new trend for long‐distance offshore wind power transmission. In order to facilitate the derivation of the feedforward DC voltage control based fault ride through (FRT) technique, this chapter describes...... of the proposed feedforward DC voltage control based FRT technique for VSC‐HVDC‐connected WPPs. Time‐domain simulation results shows that the proposed FRT scheme can successfully enable VSC‐HVDC‐connected WPPs to ride through balanced and unbalanced faults in host power systems, as well as faults in the WPP...

A new pneumatic suspension system with independent stiffness and ride height tuning capabilities

Science.gov (United States)

Yin, Zhihong; Khajepour, Amir; Cao, Dongpu; Ebrahimi, Babak; Guo, Konghui

2012-12-01

This paper introduces a new pneumatic spring for vehicle suspension systems, allowing independent tuning of stiffness and ride height according to different vehicle operating conditions and driver preferences. The proposed pneumatic spring comprises a double-acting pneumatic cylinder, two accumulators and a tuning subsystem. This paper presents a detailed description of the pneumatic spring and its working principle. The mathematical model is established based on principles of thermo and fluid dynamics. An experimental setup has been designed and fabricated for testing and evaluating the proposed pneumatic spring. The analytical and experimental results confirm the capability of the new pneumatic spring system for independent tuning of stiffness and ride height. The mathematical model is verified and the capabilities of the pneumatic spring are further proved. It is concluded that this new pneumatic spring provides a more flexible suspension design alternative for meeting various conflicting suspension requirements for ride comfort and performance.

Ride Quality Assessment of Bus Suspension System through Modal Frequency Response Approach

Directory of Open Access Journals (Sweden)

Y. S. Kong

2014-09-01

Full Text Available The ride dynamic characteristics of an urban bus were investigated through simulations with suspension component characteristics and were validated through field measurements. It was performed on highway road at a constant forward speed. A random vibration bus model with two parallel tracks of terrain profile was synthesized with superposition between the left and right sides as well as time delay between front and rear. The bus frequency response model was introduced with embedded modal extraction data to enhance computation efficiency. The simulation results of the bus model were derived in terms of acceleration PSD and frequency-weighted root mean square acceleration along the vertical axes at three locations, namely, driver side, middle, and rear passenger side, to obtain the overall bus ride performance. Another two sets of new leaf spring design were proposed as suspension parameter analysis. The simulation approach provides reasonably good results in evaluating passenger perception on ride and shows that the proposed new spring design can significantly improve the ride quality of the driver and passengers.

Fault ride-through enhancement of fixed speed wind turbine using bridge-type fault current limiter

Directory of Open Access Journals (Sweden)

Mostafa I. Marei

2016-05-01

Full Text Available The interaction between wind energy turbines and the grid results in two main problems, increasing the short-circuit level and reducing the Fault Ride-Through (FRT capability during faults. The objective of this paper is to solve these problems, for fixed speed Wind Energy Systems (WECS, utilizing the bridge-type Fault Current Limiter (FCL with a discharging resistor. A simple cascaded control system is proposed for the FCL to regulate the terminal voltage of the generator and limit the current. The system is simulated on PSCAD/EMTDC software to evaluate the dynamic performance of the proposed WECS compensated by FCL. The simulation results show the potentials of the FCL as a simple and effective method for solving grid interconnection problems of WECS.

Modeling and Control System Design for an Integrated Solar Generation and Energy Storage System with a Ride-Through Capability: Preprint

Energy Technology Data Exchange (ETDEWEB)

Wang, X.; Yue, M.; Muljadi, E.

2012-09-01

This paper presents a generic approach for PV panel modeling. Data for this modeling can be easily obtained from manufacturer datasheet, which provides a convenient way for the researchers and engineers to investigate the PV integration issues. A two-stage power conversion system (PCS) is adopted in this paper for the PV generation system and a Battery Energy Storage System (BESS) can be connected to the dc-link through a bi-directional dc/dc converter. In this way, the BESS can provide some ancillary services which may be required in the high penetration PV generation scenario. In this paper, the fault ride-through (FRT) capability is specifically focused. The integrated BESS and PV generation system together with the associated control systems is modeled in PSCAD and Matlab platforms and the effectiveness of the controller is validated by the simulation results.

Zero-voltage ride-through capability of single-phase grid-connected photovoltaic systems

DEFF Research Database (Denmark)

Zhang, Zhen; Yang, Yongheng; Ma, Ruiqing

2017-01-01

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...

Low-Voltage Ride-Through Operation of Power Converters in Grid-Interactive Microgrids by Using Negative-Sequence Droop Control

DEFF Research Database (Denmark)

Zhao, Xin; Guerrero, Josep M.; Savaghebi, Mehdi

2017-01-01

of the utility grid during grid faults. In this paper, a LVRT control strategy based on positive/negative sequence droop control is proposed for grid-interactive MGs to ride-through voltage sags with not only inductive/resistive, but also complex line impedance. By using the proposed control strategy, MGs can......Due to the increasing penetration level of microgrids (MGs), it becomes a critical issue for MGs to help sustaining power system stability. Therefore, ancillary services, such as the low-voltage ride-through (LVRT) capability should be incorporated in MGs in order to guarantee stable operation...... support the grid voltage, make profits, and also ride-through the voltage dip during the whole fault period. A two layer hierarchical control strategy is proposed in this paper. The primary controller consists of voltage and current inner loops, a conventional droop control and a virtual impedance loop...

Photovoltaic-STATCOM with Low Voltage Ride through Strategy and Power Quality Enhancement in a Grid Integrated Wind-PV System

Directory of Open Access Journals (Sweden)

Lakshman Naik Popavath

2018-04-01

Full Text Available The traditional configurations of power systems are changing due to the greater penetration of renewable energy sources (solar and wind, resulting in reliability issues. At present, the most severe power quality problems in distribution systems are current harmonics, reactive power demands, and the islanding of renewables caused by severe voltage variations (voltage sag and swell. Current harmonics and voltage sag strongly affect the performance of renewable-based power systems. Various conventional methods (passive filters, capacitor bank, and UPS are not able to mitigate harmonics and voltage sag completely. Based on several studies, custom power devices can mitigate harmonics completely and slightly mitigate voltage sags with reactive power supplies. To ensure the generating units remain grid-connected during voltage sags and to improve system operation during abnormal conditions, efficient and reliable utilization of PV solar farm inverter as STATCOMs is needed. This paper elaborates the dynamic performance of a VSC-based PV-STATCOM for power quality enhancement in a grid integrated system and low voltage ride through (LVRT capability. LVRT requirements suggest that the injection of real and reactive power supports grid voltage during abnormal grid conditions. The proposed strategy was demonstrated with MATLAB simulations.

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

NARCIS (Netherlands)

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

2009-01-01

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

Low voltage ride through strategies for SCIG wind turbines in distributed power generation systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Teodorescu, Remus; Rodriguez, Pedro

2008-01-01

Fulfilling the new grid codes constitutes one of the main challenges for the wind power industry, that is specially concerned about the new fault-ride-through requirements. Enhancing the operation of wind-turbines in front of grid faults is not only an important issue for new wind farms, but also...

Low-voltage ride-through of a droop-based three-phase four-wire grid-connected microgrid

DEFF Research Database (Denmark)

Sadeghkhani, Iman; Golshan, Mohamad Esmail Hamedani; Mehrizi-Sani, Ali

2018-01-01

system operations during abnormal grid conditions. The objective of this paper is to propose an LVRT scheme that improves the power quality of the entire microgrid. The developed method is implemented as the controller of the interface voltage-sourced converter (VSC) of a distributed energy resource...... control of each phase and does not require calculation of symmetrical components. Moreover, it can be employed in the VSC control systems with various reference frames and is effective for droop-based grid-connected microgrids with both single-phase and three-phase four-wire configurations. The proposed......The ability of riding through the grid disturbances can increase the integration of microgrids into the distribution system. Consequently, a grid-connected microgrid should provide ancillary services such as low voltage ride-through (LVRT) capability and reactive power support to sustain the power...

Control of Doubly-Fed Induction Generator to Ride-Through Recurring Grid Faults

DEFF Research Database (Denmark)

Chen, Wenjie; Xu, Dehong; Zhu, Nan

2016-01-01

The wind turbine system (WTS) is required to ride-through recurring grid faults by the new grid codes. Under single grid faults, the fault ride-through (FRT) strategy with rotor-side crowbar is normally used for the doubly-fed induction generator (DFIG) WTS. However, under recurring faults, larger...... transient current and voltage may be produced, and the DFIG may fail to ride-through the second fault even with the rotor-side crowbar. The crowbar can be active again during the voltage recovery, but large electromagnetic torque (EM-torque) fluctuations will be introduced. The reliability of the mechanical...... system will be influenced. In this paper, an FRT strategy for the DFIG WTS to ride-through recurring symmetrical grid faults is investigated. An improved control strategy is introduced and it is applied during the voltage recovery of the grid faults. The decay of the stator natural flux can...

Low-Voltage Ride-Through of Variable Speed Wind Turbines with Permanent Magnet Synchronous Generator

DEFF Research Database (Denmark)

Deng, Fujin; Chen, Zhe

2009-01-01

This paper presents a simulation model of a MW-level variable speed wind turbine with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed in the simulation tool of PSCAD/EMTDC. The low voltage ride-through (LVRT) capability of the wind turbine is investigated. A new...... control scheme for the wind turbine that keeps it connected to the grid during grid faults is designed and simulated. Its design has special focus on the regulation of the DC-link voltage. Simulation results show the proposed control scheme is an effective measure to improve LVRT capability of variable...

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

DEFF Research Database (Denmark)

Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi

2016-01-01

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

Advanced Reactive Power Reserve Management Scheme to Enhance LVRT Capability

Directory of Open Access Journals (Sweden)

Hwanik Lee

2017-10-01

Full Text Available Abstract: To increase the utilization of wind power in the power system, grid integration standards have been proposed for the stable integration of large-scale wind power plants. In particular, fault-ride-through capability, especially Low-Voltage-Ride-Through (LVRT, has been emphasized, as it is related to tripping in wind farms. Therefore, this paper proposes the Wind power plant applicable-Effective Reactive power Reserve (Wa-ERPR, which combines both wind power plants and conventional generators at the Point of Interconnection (POI. The reactive power capability of the doubly-fed induction generator wind farm was considered to compute the total Wa-ERPR at the POI with reactive power capability of existing generators. By using the Wa-ERPR management algorithm, in case of a violation of the LVRT standards, the amount of reactive power compensation is computed using the Wa-ERPR management scheme. The proposed scheme calculates the Wa-ERPR and computes the required reactive power, reflecting the change of the system topology pre- and post-contingency, to satisfy the LVRT criterion when LVRT regulation is not satisfied at the POI. The static synchronous compensator (STATCOM with the capacity corresponding to calculated amount of reactive power through the Wa-ERPR management scheme is applied to the POI. Therefore, it is confirmed that the wind power plant satisfies the LVRT criteria by securing the appropriate reactive power at the POI, by applying of the proposed algorithm.

Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

Directory of Open Access Journals (Sweden)

Yun Wang

2014-06-01

Full Text Available This paper presents a fast coordinated control scheme of the rotor side converter (RSC, the Direct Current (DC chopper and the grid side converter (GSC of doubly fed induction generator (DFIG wind turbine generators (WTGs to improve the low voltage ride through (LVRT and high voltage ride through (HVRT capability of the DFIG WTGs. The characteristics of DFIG WTGs under voltage sags and swells were studied focusing on the DFIG WTG stator flux and rotor voltages during the transient periods of grid voltage changes. The protection schemes of the rotor crowbar circuit and the DC chopper circuit were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were verified by time domain simulations using Matlab-Simulink.

Fault ride-through enhancement using an enhanced field oriented control technique for converters of grid connected DFIG and STATCOM for different types of faults.

Science.gov (United States)

Ananth, D V N; Nagesh Kumar, G V

2016-05-01

With increase in electric power demand, transmission lines were forced to operate close to its full load and due to the drastic change in weather conditions, thermal limit is increasing and the system is operating with less security margin. To meet the increased power demand, a doubly fed induction generator (DFIG) based wind generation system is a better alternative. For improving power flow capability and increasing security STATCOM can be adopted. As per modern grid rules, DFIG needs to operate without losing synchronism called low voltage ride through (LVRT) during severe grid faults. Hence, an enhanced field oriented control technique (EFOC) was adopted in Rotor Side Converter of DFIG converter to improve power flow transfer and to improve dynamic and transient stability. A STATCOM is coordinated to the system for obtaining much better stability and enhanced operation during grid fault. For the EFOC technique, rotor flux reference changes its value from synchronous speed to zero during fault for injecting current at the rotor slip frequency. In this process DC-Offset component of flux is controlled, decomposition during symmetric and asymmetric faults. The offset decomposition of flux will be oscillatory in a conventional field oriented control, whereas in EFOC it was aimed to damp quickly. This paper mitigates voltage and limits surge currents to enhance the operation of DFIG during symmetrical and asymmetrical faults. The system performance with different types of faults like single line to ground, double line to ground and triple line to ground was applied and compared without and with a STATCOM occurring at the point of common coupling with fault resistance of a very small value at 0.001Ω. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Cooperative control of VSC-HVDC connected offshore wind farm with Low-Voltage Ride-Through capability

DEFF Research Database (Denmark)

Liu, Yan; Wang, Xiongfei; Chen, Zhe

2012-01-01

The Low-Voltage Ride-Through (LVRT) has become an important grid requirement for offshore wind farms connecting with Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) links. In this paper, a cooperative control strategy with LVRT ability is proposed for a VSC-HVDC connected...... variable speed Squirrel-Cage Induction Generator (SCIG) wind farm. The approach employs a DC-link voltage versus offshore AC-bus frequency droop control on the offshore converter of VSC-HVDC link. Thus, the back-to-back converters of SCIG wind turbines can adjust the generated active power based on the AC......-bus frequency deviations, so that a fast power reduction on the wind farm side can be achieved. The EMTDC/PSCAD simulations are performed on a 300 MW offshore variable speed SCIG wind farm. Simulation results confirm the effectiveness of the proposed control method....

New approaches to provide ride-through for critical loads in electric power distribution systems

Science.gov (United States)

Montero-Hernandez, Oscar C.

2001-07-01

The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

Efficient fault-ride-through control strategy of DFIG-based wind turbines during the grid faults

International Nuclear Information System (INIS)

Mohammadi, J.; Afsharnia, S.; Vaez-Zadeh, S.

2014-01-01

Highlights: • A comparative review of DFIGs fault-ride-through improvement approaches is presented. • An efficient control strategy is proposed to improve the FRT capability of DFIG. • The rotor overcurrent, DC-link overvoltage and torque oscillations are decreased. • The RSC, DC-link capacitor and mechanical parts are kept safe during the grid faults. • The DFIG remains connected to the grid during the symmetrical and asymmetrical faults. - Abstract: As the penetration of wind power in electrical power system increases, it is necessary that wind turbines remain connected to the grid and contribute to the system stability during and after the grid faults. This paper proposes an efficient control strategy to improve the fault ride through (FRT) capability of doubly fed induction generator (DFIG) during the symmetrical and asymmetrical grid faults. The proposed scheme consists of active and passive FRT compensators. The active compensator is carried out by determining the rotor current references to reduce the rotor over voltages. The passive compensator is based on rotor current limiter (RCL) that considerably reduces the rotor inrush currents at the instants of occurring and clearing the grid faults with deep sags. By applying the proposed strategy, negative effects of the grid faults in the DFIG system including the rotor over currents, electromagnetic torque oscillations and DC-link over voltage are decreased. The system simulation results confirm the effectiveness of the proposed control strategy

Power Hardware In The Loop Validation of Fault Ride Through of VSC HVDC Connected Offshore Wind Power Plants

DEFF Research Database (Denmark)

Sharma, Ranjan; Wu, Qiuwei; Cha, Seung-Tae

2014-01-01

This paper presents the power hardware in the loop (PHIL) validation of a feed forward DC voltage control scheme for the fault ride through (FTR) of voltage source converter (VSC) high voltage DC (HVDC) connected offshore wind power plants (WPPs). In the proposed FRT scheme, the WPP collector...... network AC voltage is actively controlled by considering both the DC voltage error and the AC current from the WPP AC collector system which ensures fast and robust FRT of the VSC HVDC connected offshore WPPs. The PHIL tests were carried out in order to verify the efficacy of the proposed feed forward DC...... voltage control scheme for enhancing the FRT capability of the VSC HVDC connected WPPs. The PHIL test results have demonstrated the proper control coordination between the offshore WPP and the WPP side VSC and the efficient FRT of the VSC HVDC connected WPPs....

Increase in fault ride through capability of direct drive permanent magnet based wind farm using VSC-HVDC

International Nuclear Information System (INIS)

Maleki, Hesamaldin; Ramachandaramurthy, V K; Lak, Moein

2013-01-01

Burning of fossil fuels and green house gasses causes global warming. This has led to governments to explore the use of green energies instead of fossil fuels. The availability of wind has made wind technology a viable alternative for generating electrical power. Hence, many parts of the world, especially Europe are experiencing a growth in wind farms. However, by increasing the number of wind farms connected to the grid, power quality and voltage stability of grid becomes a matter of concern. In this paper, VSC-HVDC control strategy which enables the wind farm to ride-through faults and regulate voltage for fault types is proposed. The results show that the wind turbine output voltage fulfills the E.ON grid code requirements, when subjected to three phase to ground fault. Hence, continues operation of the wind farm is achieved.

Increase in fault ride through capability of direct drive permanent magnet based wind farm using VSC-HVDC

Science.gov (United States)

Maleki, Hesamaldin; Ramachandaramurthy, V. K.; Lak, Moein

2013-06-01

Burning of fossil fuels and green house gasses causes global warming. This has led to governments to explore the use of green energies instead of fossil fuels. The availability of wind has made wind technology a viable alternative for generating electrical power. Hence, many parts of the world, especially Europe are experiencing a growth in wind farms. However, by increasing the number of wind farms connected to the grid, power quality and voltage stability of grid becomes a matter of concern. In this paper, VSC-HVDC control strategy which enables the wind farm to ride-through faults and regulate voltage for fault types is proposed. The results show that the wind turbine output voltage fulfills the E.ON grid code requirements, when subjected to three phase to ground fault. Hence, continues operation of the wind farm is achieved.

Ride comfort enhancement in railway vehicle by the reduction of the car body structural flexural vibration

Science.gov (United States)

Dumitriu, M.

2017-08-01

The paper approaches the issue of reduction in the vertical bending vibrations of the railway vehicle carbody and the ride comfort enhancement at high velocities, starting from the prospect of isolating the vibrations by the best possible selection of the passive suspension damping in the vehicle. To this purpose, the examination falls on the influence of the vertical suspension damping upon the vibrations regime of the vehicle at the bending resonance frequency and upon the ride comfort. The results of the numerical simulations regarding the frequency response of the carbody acceleration and the comfort index will be therefore used. A value of the secondary suspension damping can be thus identified that will provide the best ride comfort performance. Similarly, the ride comfort can be increased by raising the primary suspension damping ratio.

A novel control strategy for enhancing the LVRT and voltage support capabilities of DFIG

Science.gov (United States)

Shen, Yangwu; Zhang, Bin; Liang, Liqing; Cui, Ting

2018-02-01

A novel integrated control strategy is proposed in this paper to enhance the low voltage ride through capacity for the double-fed induction generator by equipping an energy storage system. The energy storage system is installed into the DC-link capacitor of the DFIG and used to control the DC-link voltage during normal or transient operations. The energy storage device will absorb or compensate the power difference between the captured wind power and the power injected to the grid during the normal and transient period, and the grid side converter can be free from maintaining the voltage stability of the DC-link capacitor. Thus, the grid-side converter is changed to reactive power support while the rotor-side converter is used to control the maximum power production during normal operation. The grid-side converter and rotor-side converter will act as reactive power sources to further enhance the voltage support capability of double-fed induction generator during the transient period. Numerical Simulation are performed to validate the effectiveness of the proposed control designs.

Multi-pole permanent magnet synchronous generator wind turbines' grid support capability in uninterrupted operation during grid faults

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Michalke, G.

2009-01-01

Emphasis in this paper is on the fault ride-through and grid support capabilities of multi-pole permanent magnet synchronous generator (PMSG) wind turbines with a full-scale frequency converter. These wind turbines are announced to be very attractive, especially for large offshore wind farms...... and discussed by means of simulations with the use of a transmission power system generic model developed and delivered by the Danish Transmission System Operator Energinet.dk. The simulation results show how a PMSG wind farm equipped with an additional voltage control can help a nearby active stall wind farm....... A control strategy is presented, which enhances the fault ride-through and voltage support capability of such wind turbines during grid faults. Its design has special focus on power converters' protection and voltage control aspects. The performance of the presented control strategy is assessed...

Fault Ride-Through of a Grid-connected Photovoltaic System with Quasi Z Source Inverter

DEFF Research Database (Denmark)

Al-Durra, Ahmed; Fayyad, Yara; Muyeen, S.M.

2016-01-01

This article presents fault ride-through schemes for a three-phase quasi Z source single-stage photovoltaic (PV) inverter that is connected to the grid after the distribution network. The quasi Z source inverter employs a unique LC network to couple the inverter main circuit to the input of the PV...... the grid side so that the grid fault ride-through requirements can be fulfilled. Scheme A involves control modification in the system; Schemes B and C involve hardware modification in the circuit topology by adding a chopper circuit across the DC link in Scheme B and across the quasi Z source inverter...

Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

DEFF Research Database (Denmark)

Wang, Yun; Wu, Qiuwei; Xu, Honghua

2014-01-01

This paper presents a fast coordinated control scheme of the rotor side converter (RSC), the DC chopper and the grid side converter (GSC) of doubly fed induction generator (DFIG) wind turbine generators (WTGs) which is to improve the low voltage ride through (LVRT) and high voltage ride through...... were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were...

Using forecast information for storm ride-through control

DEFF Research Database (Denmark)

Barahona Garzón, Braulio; Trombe, Pierre-Julien; Vincent, Claire Louise

2013-01-01

Using probabilistic forecast information in control algorithms can improve the performance of wind farms during periods of extreme winds. This work presents a wind farm supervisor control concept that uses probabilistic forecast information to ride-through a storm with softer ramps of power. Wind...... speed forecasts are generated with a statistical approach (i.e. time series models). The supervisor control is based on a set of logical rules that consider point forecasts and predictive densities to ramp-down the power of the wind farm before the storm hits. The potential of this supervisor control...

Power Quality Improvement and LVRT Capability Enhancement of Wind Farms by Means of an Inductive Filtering Method

Directory of Open Access Journals (Sweden)

Yanjian Peng

2016-04-01

Full Text Available Unlike the traditional method for power quality improvement and low-voltage ride through (LVRT capability enhancement of wind farms, this paper proposes a new wind power integrated system by means of an inductive filtering method, especially if it contains a grid-connected transformer, a static synchronous compensator (STATCOM and fully-tuned (FT branches. First, the main circuit topology of the new wind power integrated system is presented. Then, the mathematical model is established to reveal the mechanism of harmonic suppression and the reactive compensation of the proposed wind power integrated system, and then the realization conditions of the inductive filtering method is obtained. Further, the control strategy of STATCOM is introduced. Based on the measured data for a real wind farm, the simulation studies are carried out to illustrate the performance of the proposed new wind power integrated system. The results indicate that the new system can not only enhance the LVRT capability of wind farms, but also prevent harmonic components flowing into the primary (grid winding of the grid-connected transformer. Moreover, since the new method can compensate for reactive power in a wind farm, the power factor at the grid side can be improved effectively.

Enhancing the LVRT Capability of PMSG-Based Wind Turbines Based on R-SFCL

Science.gov (United States)

Xu, Lin; Lin, Ruixing; Ding, Lijie; Huang, Chunjun

2018-03-01

A novel low voltage ride-through (LVRT) scheme for PMSG-based wind turbines based on the Resistor Superconducting Fault Current Limiter (R-SFCL) is proposed in this paper. The LVRT scheme is mainly formed by R-SFCL in series between the transformer and the Grid Side Converter (GSC), and basic modelling has been discussed in detail. The proposed LVRT scheme is implemented to interact with PMSG model in PSCAD/EMTDC under three phase short circuit fault condition, which proves that the proposed scheme based on R-SFCL can improve the transient performance and LVRT capability to consolidate grid connection with wind turbines.

Lean process management implementation through enhanced problem solving capabilities

Directory of Open Access Journals (Sweden)

Perumal Puvanasvaran

2010-12-01

Full Text Available All Original Equipment Manufacturers (OEM organizations in Aerospace, Automotive and Electronics industries had to upgrade their functions. These organizations including suppliers and solutions providers are duty bound to improve their functions through strategic initiatives. One such initiative is Lean Process Management. Lean Process Management has proven to aid organizations in developing manufacturing and administrative management solutions and make the organization a leaner at the same time a ‘fitter’ one, achieving World Class standards in terms of production, quality, marketing, etc, etc. The issue or problem is, although a number of authors, experts, researchers have discussed the lean process management as part organization centric issues, they failed to provide an effective lean process management system. Besides the need to formulate an effective lean process as suggested by some authors, another important reason suggested is the employee’s development aspect regarding how to unlock the infinite potential of their workforce. This employee’s development is basically the problem solving capabilities of the employees while implementing the Lean through clear cutting protocols or processes of Lean Process Management. The employees need to be developed and equipped to contribute optimally to the process. Because of this scenario, the main objective of this study is to develop an employees development system which the author has acronym or trademark it as People Development System (PDS to enhance problem solving capability among its employees while implementing the lean process management there. Although, the PDS can be implemented throughout the organization, if it is implemented in a particular department in an organization, it will be feasible to study and analyze its effectiveness in-depth. So, this study documents and analyzes the implementation of Lean process in the Kitting Department of the aerospace company, ABC Company

Elevator ride comfort monitoring and evaluation using smartphones

Science.gov (United States)

Zhang, Yang; Sun, Xiaowei; Zhao, Xuefeng; Su, Wensheng

2018-05-01

With rapid urbanization, the demand for elevators is increasing, and their level of safety and ride comfort under vibrating conditions has also aroused interest. It is therefore essential to monitor the ride comfort level of elevators. The traditional method for such monitoring depends significantly on regular professional inspections, and requires expensive equipment and professional skill. With this regard, a new method for elevator ride comfort monitoring using a smartphone is demonstrated herein in detail. A variety of high-precision sensors are installed in a smartphone with strong data processing and telecommunication capabilities. A series of validation tests were designed and completed, and the international organization for standardization ISO2631-1997 was applied to evaluate the level of elevator ride comfort. Experimental results indicate that the proposed method is stable and reliable, its precision meets the engineering requirements, and the elevator ride comfort level can be accurately monitored under various situations. The method is very economical and convenient, and provides the possibility for the public to participate in elevator ride comfort monitoring. In addition, the method can both provide a wide range of data support and eliminate data errors to a certain extent.

An adaptive Phase-Locked Loop algorithm for faster fault ride through performance of interconnected renewable energy sources

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2013-01-01

Interconnected renewable energy sources require fast and accurate fault ride through operation in order to support the power grid when faults occur. This paper proposes an adaptive Phase-Locked Loop (adaptive dαβPLL) algorithm, which can be used for a faster and more accurate response of the grid...... side converter control of a renewable energy source, especially under fault ride through operation. The adaptive dαβPLL is based on modifying the control parameters of the dαβPLL according to the type and voltage characteristic of the grid fault with the purpose of accelerating the performance...

A STATCOM with Supercapacitors for Low-Voltage Ride-Through in Fixed-Speed Wind Turbines

Directory of Open Access Journals (Sweden)

Andrés Felipe Obando-Montaño

2014-09-01

Full Text Available Fixed-speed wind generator (FSWG technology has an important presence in countries where wind energy started to be developed more than a decade ago. This type of technology cannot be directly adapted to the grid codes, for example those requirements related to the immunity level under voltage dips. That behavior is typically referred as low-voltage ride through (LVRT, and it usually implies certain reactive and active power injection requirements, both during a voltage dip and during the voltage recovery. In this context, a review is presented of the LVRT exigencies present in some of the countries with the most advanced grid codes (Denmark, Germany, Spain and the United Kingdom. In this paper, the capabilities of STATCOM-based devices for fulfilling the LVRT requirements in FSWGs are analyzed. For this purpose, two technologies are considered: a STATCOM with a supercapacitor, which improves its energy storage features; and a STATCOM with a supercapacitor and a DC-DC converter, to achieve higher discharge levels.

Coordinated Low Voltage Ride through strategies for Permanent Magnet Direct Drive Synchronous Generators

Directory of Open Access Journals (Sweden)

Zhang Ge

2016-01-01

Full Text Available By analyzing the mechanism of the low voltage ride through on the permanent magnet direct drive synchronous wind power generating units, this paper proposes a coordinated control strategy for permanent magnet synchronous generator. In order to avoid over speed operation of the generation units, over voltage on DC capacitor and over current on convert, the improved pitch angle control and inverter control are used. When the grid voltage drops, the captured wind power is cut down by the variable pitch system, which limits the speed of the generator, the generator side converter keeps the DC capacitor voltage stabile; and the grid side converter provides reactive power to the grid to help the grid voltage recover. The control strategy does not require any additional hardware equipment, with existing control means, the unit will be able to realize low voltage ride through. Finally, based on Matlab/Simulink to build permanent magnet direct drive wind power generation system, the simulation results verify the correctness and effectiveness of the control strategy.

A Low-Voltage Ride-Through Control Strategy for Three-Phase Grid-Connected PV Systems

DEFF Research Database (Denmark)

Afshari, Ehsan; Farhangi, Babak; Yang, Yongheng

2017-01-01

similar variations in the dc-link voltage of conventional two-stage PV inverters. In such systems with an electrolytic capacitor in the dc-link, the oscillations of the dc-link voltage with DGF can deteriorate the capacitor lifetime, and thus the entire system. The proposed Low-Voltage Ride-Through (LVRT...

Differential Evolution Based IDWNN Controller for Fault Ride-Through of Grid-Connected Doubly Fed Induction Wind Generators.

Science.gov (United States)

Manonmani, N; Subbiah, V; Sivakumar, L

2015-01-01

The key objective of wind turbine development is to ensure that output power is continuously increased. It is authenticated that wind turbines (WTs) supply the necessary reactive power to the grid at the time of fault and after fault to aid the flowing grid voltage. At this juncture, this paper introduces a novel heuristic based controller module employing differential evolution and neural network architecture to improve the low-voltage ride-through rate of grid-connected wind turbines, which are connected along with doubly fed induction generators (DFIGs). The traditional crowbar-based systems were basically applied to secure the rotor-side converter during the occurrence of grid faults. This traditional controller is found not to satisfy the desired requirement, since DFIG during the connection of crowbar acts like a squirrel cage module and absorbs the reactive power from the grid. This limitation is taken care of in this paper by introducing heuristic controllers that remove the usage of crowbar and ensure that wind turbines supply necessary reactive power to the grid during faults. The controller is designed in this paper to enhance the DFIG converter during the grid fault and this controller takes care of the ride-through fault without employing any other hardware modules. The paper introduces a double wavelet neural network controller which is appropriately tuned employing differential evolution. To validate the proposed controller module, a case study of wind farm with 1.5 MW wind turbines connected to a 25 kV distribution system exporting power to a 120 kV grid through a 30 km 25 kV feeder is carried out by simulation.

Differential Evolution Based IDWNN Controller for Fault Ride-Through of Grid-Connected Doubly Fed Induction Wind Generators

Directory of Open Access Journals (Sweden)

N. Manonmani

2015-01-01

Full Text Available The key objective of wind turbine development is to ensure that output power is continuously increased. It is authenticated that wind turbines (WTs supply the necessary reactive power to the grid at the time of fault and after fault to aid the flowing grid voltage. At this juncture, this paper introduces a novel heuristic based controller module employing differential evolution and neural network architecture to improve the low-voltage ride-through rate of grid-connected wind turbines, which are connected along with doubly fed induction generators (DFIGs. The traditional crowbar-based systems were basically applied to secure the rotor-side converter during the occurrence of grid faults. This traditional controller is found not to satisfy the desired requirement, since DFIG during the connection of crowbar acts like a squirrel cage module and absorbs the reactive power from the grid. This limitation is taken care of in this paper by introducing heuristic controllers that remove the usage of crowbar and ensure that wind turbines supply necessary reactive power to the grid during faults. The controller is designed in this paper to enhance the DFIG converter during the grid fault and this controller takes care of the ride-through fault without employing any other hardware modules. The paper introduces a double wavelet neural network controller which is appropriately tuned employing differential evolution. To validate the proposed controller module, a case study of wind farm with 1.5 MW wind turbines connected to a 25 kV distribution system exporting power to a 120 kV grid through a 30 km 25 kV feeder is carried out by simulation.

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...

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...

Effect of amusement park rides on programmable shunt valve settings.

Science.gov (United States)

Strahle, Jennifer; Collins, Kelly; Stetler, William R; Smith, Brandon W; Garton, Thomas; Garton, Catherine; Garton, Hugh J L; Maher, Cormac O

2013-01-01

Magnetically programmable shunt valves are susceptible to environmental factors including magnetic fields and accelerative forces. It is unknown if rollercoasters with or without magnetic brakes or linear induction motors (LIMs) are capable of altering the setting of a programmable shunt valve. Two different valve types (type A, n = 10; type B, n = 9) were tested at varying resistance settings in 2 trials on 6 different amusement park rides including 2 rides with LIMs, 2 rides with magnetic brakes, and 2 rides without magnetic technology. The performance level of valve type A and the setting of valve type B changed on rollercoasters with magnets (A = 2.5% [2/80]; B = 5.6% [4/72]) and without magnets (A = 7.5% [3/40]; B = 2.8% [1/36]). Neither valve setting changed when exposed to a Ferris wheel or during ambulation throughout the park. Magnetically programmable valves are susceptible to changes in pressure settings when exposed to amusement park rides with elevated vertical gravitational forces, irrespective of the presence of LIMs or magnetic brakes. © 2013 S. Karger AG, Basel.

Impact of fault ride-through requirements on fixed-speed wind turbine structural loads

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Markou, Helen

2011-01-01

by performing a rainflow and a statistical analysis for fatigue and ultimate structural loads, respectively. Two cases are compared i.e. one where the turbine is immediately disconnected from the grid when a grid fault occurs and one where the turbine is equipped with a fault ride-through controller...... and therefore it is able to remain connected to the grid during the grid fault. Copyright © 2010 John Wiley & Sons, Ltd....

An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

Science.gov (United States)

Gayen, P K; Chatterjee, D; Goswami, S K

2016-05-01

In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Riding Bikes: A Pastime for Every Child

Science.gov (United States)

Mathias, Michelle

2011-01-01

People have heard the expression "It's as easy as riding a bike." But the idea of a child with special needs balancing, steering, and pedaling a bike can seem out of reach for some; especially when he may be unable to walk unaided or hold his head up without support. Physical capabilities or stamina need not keep a child from this pleasurable…

Internal balance during low-voltage-ride-through of the modular multilevel converter statcom

DEFF Research Database (Denmark)

Tsolaridis, Georgios; Kontos, Epameinondas; Chaudhary, Sanjay K.

2017-01-01

on the challenging internal control of the converter to allow the independent control of the energy levels of each arm, with the goal to maintain internal balancing of the MMC during contingencies. Extensive experimental results highlight the need for a sophisticated internal control. Moreover, the experimental...... analysis verifies that, by using the proposed control structure, the MMC can effectively ride through a fault on the AC side without tripping, while injecting the necessary positive and negative sequence reactive current levels according to the most recent grid codes....

Coordinated control for low voltage ride-through of a PMSG-based wind power plant

Directory of Open Access Journals (Sweden)

Khagendra Thapa

2016-01-01

Full Text Available Wind turbine generators should be kept connected to a power grid, while supporting the voltage recovery in the case of a grid fault to meet low voltage ride-through requirement in some grid codes. This paper proposes a coordinated control scheme that prevents the increase in the DC-link voltage by reducing the active power in the machine side converter of permanent magnet synchronous generators (PMSGs in proportion to the voltage dip at the terminal of PMSGs. The proposed scheme changes the current priorities from the active current to the reactive current to inject more reactive power for a severe fault depending on the voltage dip. In addition, the grid-side converter operates in a voltage control mode with the slope, which is the ratio of reactive current capability to the voltage tolerance around a rated value. Moreover, during the fault, the slope is changed depending on the voltage dip to inject more reactive current. The performance of the proposed scheme is validated for a wind power plant consisting of 20 units of 5-MW PMSGs using an EMTP-RV simulator. The results demonstrate that the scheme enables the PMSGs not only to survive during the fault, but also to provide a dynamic reactive power support.

The Enhancement of Regional Disaster Management Agencies (BPBD of Sumbawa Regency’s Capability in Flash Flood Management Through Aid Assistance of Japan International Cooperation Agency (JICA

Directory of Open Access Journals (Sweden)

Nudia Vebina Ayumahani

2018-03-01

Full Text Available The need for enhancing capability has a very important significance in effective disaster management activities. Regional Disaster Management Agencies (BPBD of Sumbawa Regency established cooperation with the Japan International Cooperation Agency (JICA in enhancing the capability of flash flood management. The purpose of this research was to review and evaluate the JICA’s aid assistance programs toward BPBD of Sumbawa Regency, hereafter analyze the impact of the programs. Evaluation and analysis of this research were measured by three indicators of capability which is resources, leadership and policy implementation. This research used a qualitative descriptive method and proceed through the source and method triangulation. The researcher used purposive sampling technique in choosing seven informants from BPBD of Sumbawa Regency’s staff. The results showed that JICA’s aid assistance programs towards BPBD of Sumbawa Regency had been achieved by the targets and goals that have been determined. This program has impacted on enhancing the capability of resources that leads to the ability in Mapping, Technical Guidelines (JUKNIS and Disaster Management Plan (RPB. Increasing the capability of Human Resources (HR gives the effect of increasing capability in other fields such as financial resource capability, technical resource capability, leadership capability and policy implementation capability. The main factors in the success of the capability enhancement are the discipline factor of BPBD staff, high willingness to improve capability by BPBD staff, capability- enhancing programs, and clear direction from JICA.

Thermal Optimized Operation of the Single-Phase Full-Bridge PV Inverter under Low Voltage Ride-Through Mode

DEFF Research Database (Denmark)

Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

2013-01-01

The efficiency of 98% has been reported on transformer-less photovoltaic (PV) inverters and the penetration of grid-connected PV systems is booming as well. In the future, the PV systems are expected to contribute to the grid stability by means of low voltage ride-through operation and grid suppo...

PERANCANGAN PURWARUPA KOMIK INTERAKTIF SAFETY RIDING BERKONSEP DIGITAL STORYTELLING

Directory of Open Access Journals (Sweden)

Godham Eko Saputro

2016-12-01

Full Text Available Abstrak Di Indonesia khususnya kota besar, kecelakaan yang disebabkan kendaraan bermotor menjadi persoalan yang serius. Salah satunya disebabkan kurangnya pemahaman tentang safety riding. Berbagai upaya kampanye safety riding pun telah dilaksanakan oleh polisi lalu lintas melalui talkshow, siaran radio, serta media leaflet bagi masyarakat yang dilakukan berulang-ulang. Hal itu mendorong peneliti dalam upaya menemukan strategi baru, salah satunya memanfaatkan perkembangan teknologi yang sangat pesat guna mengembangkan media pendukung kampanye safety riding yang tidak hanya dapat menyampaikan pesan, tetapi juga disukai dan bersifat menghibur. Data diperoleh melalui wawancara, observasi, serta studi literatur sebagai sumber konten purwarupa komik interaktif. Melalui pendekatan digital storytelling dan model komunikasi SMCR serta mengacu pada Penelitian Pengembangan, konsep purwarupa komik interaktif bisa dijabarkan lebih detail serta dapat diimplementasikan dalam perangkat mobile khususnya tablet PC. Diharapkan purwarupa ini dapat dikembangkan lebih lanjut sehingga benar-benar dapat dipublish secara umum sebagai media pendukung kampanye safety riding. Kata Kunci: komik, interaktif, safety riding, digital storytelling Abstract In Indonesia especially in big cities, the accident which caused by rider is still become serious issue. One factor which cause accident is the lack of knowledge about safety riding. A lot of efforts which have been carried by traffic policeman are talkshow, radio broadcast, and leaflet media for public society. On the other hand, it courage the researchers in effort to find new startegy, one of them is using the advance of technology to develop another media campaign which not only can deliver the messages, but also can entertain user. This research is an effort to find unconventional media for safety riding campaign. Data was obtained through interview, observation, and study of literature as sources of content for

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

Science.gov (United States)

Cai, Guowei; Liu, Cheng; Yang, Deyou

2013-11-01

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

Air riding seal with purge cavity

Science.gov (United States)

Sexton, Thomas D; Mills, Jacob A

2017-08-15

An air riding seal for a turbine in a gas turbine engine, where an annular piston is axial moveable within an annular piston chamber formed in a stator of the turbine and forms a seal with a surface on the rotor using pressurized air that forms a cushion in a pocket of the annular piston. A purge cavity is formed on the annular piston and is connected to a purge hole that extends through the annular piston to a lower pressure region around the annular piston or through the rotor to an opposite side. The annular piston is sealed also with inner and outer seals that can be a labyrinth seal to form an additional seal than the cushion of air in the pocket to prevent the face of the air riding seal from overheating.

Fault-Ride through Strategy for Permanent-Magnet Synchronous Generators in Variable-Speed Wind Turbines

Directory of Open Access Journals (Sweden)

Mohamed Abdelrahem

2016-12-01

Full Text Available Currently, the electric power production by wind energy conversion systems (WECSs has increased significantly. Consequently, wind turbine (WT generators are requested to fulfill the grid code (GC requirements stated by network operators. In case of grid faults/voltage dips, a mismatch between the generated active power from the wind generator and the active power delivered to the grid is produced. The conventional approach is using a braking chopper (BC in the DC-link to dissipate this active power. This paper proposes a fault-ride through (FRT strategy for variable-speed WECSs based on permanent magnet synchronous generators (PMSGs. The proposed strategy exploits the rotor inertia of the WECS (inertia of the WT and PMSG to store the surplus active power during the grid faults/voltage dips. Thus, no additional hardware components are requested. Furthermore, a direct model predictive control (DMPC scheme for the PMSG is proposed in order to enhance the dynamic behavior of the WECS. The behavior of the proposed FRT strategy is verified and compared with the conventional BC approach for all the operation conditions by simulation results. Finally, the simulation results confirm the feasibility of the proposed FRT strategy.

Dial-a-Ride

DEFF Research Database (Denmark)

Jørgensen, Rene Munk

2003-01-01

The Dial-a-Ride problem is a Vehicle Routing problem in its most general form. The problem was formulated in the beginning of the 1970's and since then a large number of researchers have worked on developing efficient algorithms for use in automated planning of Dial-a-Ride transportation systems....... In a Dial-a-Ride transportation system, passengers request a trip between two stops with either a desired time of departure from the pickup stop or a desired time of arrival at the destination. The time windows at the stops are then calculated by the operator based on additional parameters such as maximum...... to the problem. The metod used in this thesis is based on a clustering first insertion second technique developed at CRT in Canada in the mid 1980's. The algorithm is extended to include constraints imposed by a practical Dial-a-Ride problem at a Danish transportation operator. These constraints are mainly...

A First Step toward the Understanding of Implicit Learning of Hazard Anticipation in Inexperienced Road Users Through a Moped-Riding Simulator

Directory of Open Access Journals (Sweden)

Mariaelena Tagliabue

2017-05-01

Full Text Available Hazard perception is considered one of the most important abilities in road safety. Several efforts have been devoted to investigating how it improves with experience and can be trained. Recently, research has focused on the implicit aspects of hazard detection, reaction, and anticipation. In the present study, we attempted to understand how the ability to anticipate hazards develops during training with a moped-riding simulator: the Honda Riding Trainer (HRT. Several studies have already validated the HRT as a tool to enhance adolescents’ hazard perception and riding abilities. In the present study, as an index of hazard anticipation, we used skin conductance response (SCR, which has been demonstrated to be linked to affective/implicit appraisal of risk. We administered to a group of inexperienced road users five road courses two times a week apart. In each course, participants had to deal with eight hazard scenes (except one course that included only seven hazard scenes. Participants had to ride along the HRT courses, facing the potentially hazardous situations, following traffic rules, and trying to avoid accidents. During the task, we measured SCR and monitored driving performance. The main results show that learning to ride the simulator leads to both a reduction in the number of accidents and anticipation of the somatic response related to hazard detection, as proven by the reduction of SCR onset recorded in the second session. The finding that the SCR signaling the impending hazard appears earlier when the already encountered hazard situations are faced anew suggests that training with the simulator acts on the somatic activation associated with the experience of risky situations, improving its effectiveness in detecting hazards in advance so as to avoid accidents. This represents the starting point for future investigations into the process of generalization of learning acquired in new virtual situations and in real-road situations.

Ride comfort analysis with physiological parameters for an e-health train.

Science.gov (United States)

Lee, Youngbum; Shin, Kwangsoo; Lee, Sangjoon; Song, Yongsoo; Han, Sungho; Lee, Myoungho

2009-12-01

Transportation by train has numerous advantages over road transportation, especially with regard to energy efficiency, ecological features, safety, and punctuality. However, the contrast in ride comfort between standard road transportation and train travel has become a competitive issue. The ride comfort enhancement technology of tilting trains (TTX) is a particularly important issue in the development of the Korean high-speed railroad business. Ride comfort is now defined in international standards such as UIC13 and ISO2631. The Korean standards such as KSR9216 mainly address physical parameters such as vibration and noise. In the area of ride comfort, living quality parameter techniques have recently been considered in Korea, Japan, and Europe. This study introduces biological parameters, particularly variations in heart rate, as a more direct measure of comfort. Biological parameters are based on physiological responses rather than on purely external mechanical parameters. Variability of heart rate and other physiological parameters of passengers are measured in a simulation involving changes in the tilting angle of the TTX. This research is a preliminary study for the implementation of an e-health train, which would provide passengers with optimized ride comfort. The e-health train would also provide feedback on altered ride comfort situations that can improve a passenger's experience and provide a healthcare service on the train. The aim of this research was to develop a ride comfort evaluation system for the railway industry, the automobile industry, and the air industry. The degree of tilt correlated with heart rate, fatigue, and unrelieved alertness.

The Effects of Ride Hailing Services on Travel and Associated Greenhouse Gas Emissions

Science.gov (United States)

2018-04-01

Towards the close of the first decade of the 21st Century, ride-hailing services began to enter the transportation market through smart phone applications that allowed consumers to hail and pay for a ride from drivers using their own vehicle. The inf...

Physiological demands of off-road vehicle riding.

Science.gov (United States)

Burr, Jamie F; Jamnik, Veronica K; Shaw, Jim A; Gledhill, Norman

2010-07-01

The purpose of this study was to characterize the physiological demands of recreational off-road vehicle riding under typical riding conditions using habitual recreational off-road vehicle riders (n = 128). Comparisons of the physical demands of off-road vehicle riding were made between vehicle types (all-terrain vehicle (ATV) and off-road motorcycle (ORM)) to the demands of common recreational activities. Habitual riders (ATV = 56, ORM = 72) performed strength assessments before and after a representative trail ride (48 +/- 24.2 min), and ambulatory oxygen consumption was measured during one lap (24.2 +/- 11.8 min) of the ride. The mean VO2 requirement (mL x kg(-1) x min(-1)) while riding an off-road vehicle was 12.1 +/- 4.9 for ATV and 21.3 +/- 7.1 for ORM (P = 0.002), which is comparable to the VO2 required of many common recreational activities. Temporal analysis of activity intensity revealed approximately 14% of an ATV ride and 38% of an ORM ride are within the intensity range (940% VO2 reserve) required to achieve changes in aerobic fitness. Riding on a representative course also led to muscular fatigue, particularly in the upper body. On the basis of the measured metabolic demands, evidence of muscular strength requirements, and the associated caloric expenditures with off-road vehicle riding, this alternative form of activity conforms to the recommended physical activity guidelines and can be effective for achieving beneficial changes in health and fitness.

14 CFR 23.1399 - Riding light.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 23.1399 Section 23.1399... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian, must be installed so that it...

14 CFR 27.1399 - Riding light.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 29.1399 - Riding light.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 25.1399 - Riding light.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

Driving self-regulation and ride service utilization in a multicommunity, multistate sample of U.S. older adults.

Science.gov (United States)

Bird, Donna C; Freund, Katherine; Fortinsky, Richard H; Staplin, Loren; West, Bethany A; Bergen, Gwen; Downs, Jonathan

2017-04-03

This study examined a multicommunity alternative transportation program available 24 hours a day, 7 days a week, for any purpose, offering door-through-door service in private automobiles to members who either do not drive or are transitioning away from driving. Specific aims were to describe the characteristics of members by driving status and ride service usage of these members. Data came from administrative records maintained by a nonprofit ride service program and include 2,661 individuals aged 65+ residing in 14 states who joined the program between April 1, 2010, and November 8, 2013. Latent class analysis was used to group current drivers into 3 classes of driving status of low, medium, and high self-regulation, based on their self-reported avoidance of certain driving situations and weekly driving frequency. Demographics and ride service use rate for rides taken through March 31, 2014, by type of ride (e.g., medical, social, etc.) were calculated for nondrivers and drivers in each driving status class. The majority of ride service users were female (77%) and aged 65-74 years (82%). The primary method of getting around when enrolling for the transportation service was by riding with a friend or family member (60%). Among the 67,883 rides given, nondrivers took the majority (69%) of rides. Medical rides were the most common, accounting for 40% of all rides. Reported ride usage suggests that older adults are willing to use such ride services for a variety of trips when these services are not limited to specific types (e.g., medical). Further research can help tailor strategies to encourage both nondrivers and drivers to make better use of alternative transportation that meets the special needs of older people.

The contribution of attention in virtual moped riding training of teenagers.

Science.gov (United States)

Tagliabue, Mariaelena; Da Pos, Osvaldo; Spoto, Andrea; Vidotto, Giulio

2013-08-01

Riding a moped, like many other everyday activities, is a complex behavior in which attention plays a crucial role. This study aims to investigate the role of attention in enhancing the skills required to ride a moped simulator. Two experiments were conducted with 207 and 60 students (14-15 years old), respectively, using a moped simulator to ride on 12 different tracks. The assignment was to ride safely and avoid hazards. In experiment 1, we divided the hazard scenes of the tracks on the basis of the fact that a shift in attention was required to escape the danger. We showed that during the riding training, when no attentional shift was required, the ability to avoid hazards was constantly higher. In experiment 2, participants were asked to cope with the same basic experimental setting but with an additional attentive task. The results showed that they performed in such a way that not only did the attentive task not impair their performance, but it also produced an improvement in the ability to shift attentional focus, preserving performance efficiency. On the basis of these data, it can be claimed that, primarily, attentional shift plays a prominent role in accounting for accident circumstances. Secondarily, it can be claimed that attentional training contributes to improved processing efficiency so as to prevent mishaps. Copyright © 2013 Elsevier Ltd. All rights reserved.

In-depth investigation of escalator riding accidents in heavy capacity MRT stations.

Science.gov (United States)

Chi, Chia-Fen; Chang, Tin-Chang; Tsou, Chi-Lin

2006-07-01

In 2000, the accident rate for escalator riding was about 0.815 accidents per million passenger trips through Taipei Metro Rapid Transit (MRT) heavy capacity stations. In order to reduce the probability and severity of escalator riding accidents and enhance the safety of passengers, the Drury and Brill model [Drury, C.G., Brill, M., 1983. Human factors in consumer product accident investigation. Hum. Factors 25 (3), 329-342] for in-depth investigation was adopted to analyze the 194 escalator riding accidents in terms of victim, task, product and environment. Prevention measures have been developed based on the major causes of accidents and other related contributing factors. The results from the analysis indicated that the majority of the escalator riding accidents was caused by passengers' carrying out other tasks (38 cases, including carrying luggage 24 cases, looking after accompany persons 9 cases, and 5 others), loss of balance (26 cases, 13.4%), not holding the handrail (20 cases, 10.3%), unhealthy passengers (18 cases, 9.3%), followed by people struck by other passenger (16 cases, 8.2%). For female passengers aged 15-64 years, their rushing for trains accidents could have been prevented by wearing safer footwear or by appropriate signing being provided indicating the location and traveling direction of escalators. Female passengers aged 65 years and above whose accidents were caused by loss of balance, should be encouraged to take the elevator instead. To prevent entrapment injuries, following a stricter design code can be most effective. Further in-depth accident investigation is suggested to cover the activity of the victim prior to the accident, any involved product, the location of the accident on the escalator, any medical treatment, what went wrong, opinion of the respondent on the causes of the accident, and personal characteristics of the passengers. Also, management must trade off productivity and safety appropriately to prevent "Organizational

Behavior and Development: Physical Development--"Riding Along" Outdoors!

Science.gov (United States)

Strickland, Eric

2005-01-01

Riding toys and push-pull toys are traditionally part of every early childhood program. Young children can develop a wide variety of skills and get numerous health benefits from riding toys if one is careful and thoughtful in setting up the riding-toy area. This article describes various types of riding toys and activity ideas to enhance…

Influence of Crowbar and Chopper Protection on DFIG during Low Voltage Ride Through

Directory of Open Access Journals (Sweden)

Rita M. Monteiro Pereira

2018-04-01

Full Text Available The energy sector is evolving rapidly, namely due to the increasing importance of renewable energy sources. The connection of large amounts of wind power generation poses new challenges for the dynamic voltage stability analysis of an electric power system, which has to be studied. In this paper, the traditional Doubly-Fed Induction Generator model is employed. Based on this model, a crowbar and chopper circuit is set up to protect the turbine during the short-circuit period. The EUROSTAG software package was used for the simulation studies of the system, and numerical results were obtained. Conclusions are drawn that provide a better understanding of the influence of crowbar and chopper protection on Doubly-Fed Induction Generators (DFIG, during low voltage ride through, in a system with wind power generation.

Design and Research on Platform to Enhance College Students’ Art Appreciation Capability Based on Modern Information Technology

Directory of Open Access Journals (Sweden)

Shen Xifei

2015-01-01

Full Text Available Nowadays, with the rapid development of modern information technology, the college students could not preferably choose and learn to enhance their own art appreciation capability. Therefore, the colleges and universities have a more urgent desire to organize, develop and provide a good platform to enhance the college students’ art appreciation capability based on modern information technology. This paper describes how to enhance the art appreciation capability in detail, and designs and analyzes the platform to enhance college students’ art appreciation capability based on modern information technology---the “Music Corner” and the “Dance Corner”, indicating that the exchange platform built with modern information technology can promotes the college students’ art appreciation capability. Finally, through the analysis of statistical results of the questionnaire, college students are fonder of art appreciation after the establishment of platform, more inclined to the comprehensive learning of art, more brave to express their own sense of art, and fonder of artistic creation.

The Theory of Dynamic Public Transit Priority with Dynamic Stochastic Park and Ride

Directory of Open Access Journals (Sweden)

Chengming Zhu

2014-01-01

Full Text Available Public transit priority is very important for relieving traffic congestion. The connotation of dynamic public transit priority and dynamic stochastic park and ride is presented. Based on the point that the travel cost of public transit is not higher than the travel cost of car, how to determine the level of dynamic public transit priority is discussed. The traffic organization method of dynamic public transit priority is introduced. For dynamic stochastic park and ride, layout principle, scale, and charging standard are discussed. Traveler acceptability is high through the analysis of questionnaire survey. Dynamic public transit priority with dynamic stochastic park and ride has application feasibility.

Enhancement of Training Capabilities in VVER Technology Through Establishment of VVER Training Academy

International Nuclear Information System (INIS)

Ilieva, M.; Miteva, R.

2015-01-01

Education and training (E&T) have always been key factor to the sustainability of the nuclear industry. With regard to E&T it is still the challenge to raise the interest of qualified young people of studies and professions related to nuclear technologies. CORONA Project is established to provide a special purpose structure for training and for gathering the existing and generating new knowledge in the VVER area as well as to contribute to transnational mobility and lifelong learning amongst VVER operating countries. CORONA Project consists of two parts: CORONA I (2011–2014) “Establishment of a regional centre of competence for VVER technology and Nuclear Applications”, co-financed by the EC Framework Programme 7 and CORONA II “Enhancement of training capabilities in VVER technology through establishment of VVER training academy”, co-financed by the EURATOM 2014-2015 Working programme of HORIZON 2020. The project is focused on development of training schemes for VVER nuclear professionals, subcontractors, students and for non-nuclear specialists working in support of nuclear applications as civil engineers, physical protection employees, government employees, secondary school teachers, journalists. Safety culture and soft skills training are incorporated as an integral part of all training schemes because they require continuous consideration. It is vital for the acceptance of nuclear energy by the public and for the safe performance of the nuclear installations. CORONA II project is to proceed with the development of state-of-the-art virtual training centre — CORONA Academy. This objective will be realised through networking between universities, research organizations, regulatory bodies, industry and any other organizations involved in the application of nuclear science, ionising radiation and nuclear safety. It will bring together the most experienced trainers and will allow trainees from different locations to access the needed knowledge on demand

Enhancement of DFIG-Wind Turbine’s LVRT capability using novel DVR based Odd-nary Cascaded Asymmetric Multi-Level Inverter

Directory of Open Access Journals (Sweden)

A.D. Falehi

2017-06-01

Full Text Available One of the most prominent issues relevant to Doubly Fed Induction Generator (DFIG is augmentation of its Low Voltage Ride Through (LVRT capability. Dynamic Voltage Restorer (DVR is a series kind of Distributed-Flexible AC Transmission Systems (D-FACTS that is here occupied to preserve the DFIG from the voltage sag whenever a fault to be occurred in the power system. Multi-Level Inverter (MLI is the beating-heart of DVR with unique responsibility of synthesizing a staircase sinusoidal voltage from the DC voltage sources. In this regard, it is immensely important a high performance and cost-effective MLI to be embedded into the DVR. In this paper, a novel MLI is introduced to provide a staircase sinusoidal voltage with high level numbers against less switch numbers as compared to the other kinds of MLIs. By adding the bi-directional switches and capacitors of sub-MLI as well as amount of DC sources, the held forth MLI can also operate as so-called “Odd-nary” Cascaded Asymmetric Multi-Level Inverter (OCAMLI. The performance of proposed DVR based on OCAMLI i.e., DVR-OCAMLI has been thoroughly evaluated under deep and shallow balanced and unbalanced voltage sags so that its LVRT capability to be cleared up. To more scrutinize the performance of DVR-OCAMLI, it has been withal dealt with under severe and slight voltage swells as well as harmonic voltage. The accuracy and performance of DVR-OCAMLI has been furthermore compared with conventional DVR. To sum up, the relevant analytical study along with the simulation results has transparently corroborated the performance of OCAMLI as compared to other MLIs. Meanwhile, the DVR-OCAMLI has significantly compensated deep and shallow symmetric and asymmetric voltage sags to enhance the LVRT capability of DFIG; correspondingly, the severe and slight symmetric and asymmetric voltage swells as well as voltage harmonic have been exceptionally compensated as compared to conventional DVR.

Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

Energy Technology Data Exchange (ETDEWEB)

Chen, Lei, E-mail: stclchen1982@163.com [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zhu, Lin [Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville 37996 (United States); Guo, Fang [Department of Substation, Guang Dong Electric Power Design Institute, Guangzhou 510663 (China)

2015-11-15

Highlights: • A modified flux-coupling type SFCL is suggested to enhance the transient performance of a micro-grid. • The SFCL’s main contribution is to improve the micro-grid’s fault ride-through capability. • The SFCL also can make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. • The simulations show that the SFCL can availably strengthen the micro-grid’s voltage and frequency stability. - Abstract: Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid’s operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid’s fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL’s contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

International Nuclear Information System (INIS)

Chen, Lei; Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui; Zhu, Lin; Guo, Fang

2015-01-01

Highlights: • A modified flux-coupling type SFCL is suggested to enhance the transient performance of a micro-grid. • The SFCL’s main contribution is to improve the micro-grid’s fault ride-through capability. • The SFCL also can make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. • The simulations show that the SFCL can availably strengthen the micro-grid’s voltage and frequency stability. - Abstract: Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid’s operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid’s fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL’s contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

Improved DFIG Capability during Asymmetrical Grid Faults

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2015-01-01

In the wind power application, different asymmetrical types of the grid fault can be categorized after the Y/d transformer, and the positive and negative components of a single-phase fault, phase-to-phase fault, and two-phase fault can be summarized. Due to the newly introduced negative and even...... the natural component of the Doubly-Fed Induction Generator (DFIG) stator flux during the fault period, their effects on the rotor voltage can be investigated. It is concluded that the phase-to-phase fault has the worst scenario due to its highest introduction of the negative stator flux. Afterwards......, the capability of a 2 MW DFIG to ride through asymmetrical grid faults can be estimated at the existing design of the power electronics converter. Finally, a control scheme aimed to improve the DFIG capability is proposed and the simulation results validate its feasibility....

[Riding therapy in the rehabilitation of mobility-impaired children].

Science.gov (United States)

Mäenpää, Helena; Kela, Katri; Sätilä, Heli

2016-01-01

Riding therapy is a comprehensive and functional form of rehabilitation, in which the rehabilitee, the horse and the riding therapist collaborate in order to achieve individually assigned goals that support rehabilitation. In Finland, riding therapy is therapeutic rehabilitation carried out by riding therapists who have undergone approved training. The therapy is mainly implemented in an individual form, but small group working is also applied, e.g. in the form of pair therapy and therapeutic vaulting. In Europe, this form of rehabilitation has been divided into hippotherapy supporting motor functions and heilpedagogical riding therapy functioning in support of upbringing.

FDI based on Artificial Neural Network for Low-Voltage-Ride-Through in DFIG-based Wind Turbine.

Science.gov (United States)

Adouni, Amel; Chariag, Dhia; Diallo, Demba; Ben Hamed, Mouna; Sbita, Lassaâd

2016-09-01

As per modern electrical grid rules, Wind Turbine needs to operate continually even in presence severe grid faults as Low Voltage Ride Through (LVRT). Hence, a new LVRT Fault Detection and Identification (FDI) procedure has been developed to take the appropriate decision in order to develop the convenient control strategy. To obtain much better decision and enhanced FDI during grid fault, the proposed procedure is based on voltage indicators analysis using a new Artificial Neural Network architecture (ANN). In fact, two features are extracted (the amplitude and the angle phase). It is divided into two steps. The first is fault indicators generation and the second is indicators analysis for fault diagnosis. The first step is composed of six ANNs which are dedicated to describe the three phases of the grid (three amplitudes and three angle phases). Regarding to the second step, it is composed of a single ANN which analysis the indicators and generates a decision signal that describes the function mode (healthy or faulty). On other hand, the decision signal identifies the fault type. It allows distinguishing between the four faulty types. The diagnosis procedure is tested in simulation and experimental prototype. The obtained results confirm and approve its efficiency, rapidity, robustness and immunity to the noise and unknown inputs. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Enhancement of kalman filter single loss detection capability

International Nuclear Information System (INIS)

Morrison, G.W.; Downing, D.J.; Pike, D.H.

1980-01-01

A new technique to significantly increase the sensitivity of the Kalman filter to detect one-time losses for nuclear marterial accountability and control has been developed. The technique uses the innovations sequence obtained from a Kalman filter analysis of a material balance area. The innovations are distributed as zero mean independent Gaussion random variables with known variance. This property enables an estimator to be formed with enhanced one time loss detection capabilities. Simulation studies of a material balance area indicate the new estimator greatly enhances the one time loss detection capability of the Kalman filter

Enhancing PLiM/LCM through integration strategies

International Nuclear Information System (INIS)

Dam, R.F.; Watson, P.; Nickerson, J.H.

2004-01-01

Plant Life Management and Life Cycle Management activities continue to become an increasingly important part of NPP planning and O and M efforts. AECL, as a developer and provider of PLiM/LCM products and services, has been working towards providing effective and efficient tools and processes to support this activity. As these products evolve, it is becoming evident that there are significant benefits from ensuring that AECL and their utility partners engage in an Integrated PLiM approach. The integration of PLiM products and services goes far beyond simply relating the various aspects of the technology. The strategy to enhance the integration of PLiM includes three specific areas; namely the integrated aging knowledge base, the integrated assessment technology, and the integrated implementation within the plant. Through integration at all these levels the PLiM technology is able to be adaptive, providing a means for improved design and assessment capability, enhanced asset management capabilities, as well as providing for a flexible and more efficient delivery of PLiM services according to utility needs. This paper explores each of the three areas of integration, the resulting Enhanced PLiM/LCM capability, and how this capability translates to benefits for the operating stations both new and old. (author)

On-line single server dial-a-ride problems

NARCIS (Netherlands)

Feuerstein, E.; Stougie, L.

1998-01-01

In this paper results on the dial-a-ride problem with a single server are presented. Requests for rides consist of two points in a metric space, a source and a destination. A ride has to be made by the server from the source to the destination. The server travels at unit speed in the metric space

Low Voltage Ride-Through of Two-Stage Grid-Connected Photovoltaic Systems Through the Inherent Linear Power-Voltage Characteristic

DEFF Research Database (Denmark)

Yang, Yongheng; Sangwongwanich, Ariya; Liu, Hongpeng

2017-01-01

In this paper, a cost-effective control scheme for two-stage grid-connected PhotoVoltaic (PV) systems in Low Voltage Ride-Through (LVRT) operation is proposed. In the case of LVRT, the active power injection by PV panels should be limited to prevent from inverter over-current and also energy...... aggregation at the dc-link, which will challenge the dc-link capacitor lifetime if remains uncontrolled. At the same time, reactive currents should be injected upon any demand imposed by the system operators. In the proposed scheme, the two objectives can be feasibly achieved. The active power is regulated...... point tracking controller without significant hardware or software modifications. In this way, the PV system will not operate at the maximum power point, whereas the inverter will not face any over-current challenge but can provide reactive power support in response to the grid voltage fault...

Analisis Industri Bisnis Jasa Online Ride Sharing di Indonesia

Directory of Open Access Journals (Sweden)

Berto Mulia Wibawa

2018-03-01

Full Text Available Analysis of Online Ride Sharing Business Industry in IndonesiaInnovation in transportation sector with sharing economy principal has create new service sector which is named online ride sharing service. There are a lot of online ride-sharing service players in Indonesia such as Go-Jek, Grab, and Uber. Nowadays, government also have rules on changing the condition of online ride-sharing. Therefore, industry analysis is needed to be analyze further to know the industry attractiveness of the online-ride sharing service. This study aims to analyze the level of attractiveness in online ride-sharing industry in Indonesia. This study used descriptive-explorative method on identifying Porter’s Five Forces as tools in industry analysis. Data collection is using ghost interview method to the selected driver. The conclusion is online-ride sharing industry in Indonesia is quite attractive to be developed in the future because the number of customers has not reached the maximum point, moreover the industry may offer a very diverse product differentiationDOI: 10.15408/ess.v8i1.5739

On-demand high-capacity ride-sharing via dynamic trip-vehicle assignment.

Science.gov (United States)

Alonso-Mora, Javier; Samaranayake, Samitha; Wallar, Alex; Frazzoli, Emilio; Rus, Daniela

2017-01-17

Ride-sharing services are transforming urban mobility by providing timely and convenient transportation to anybody, anywhere, and anytime. These services present enormous potential for positive societal impacts with respect to pollution, energy consumption, congestion, etc. Current mathematical models, however, do not fully address the potential of ride-sharing. Recently, a large-scale study highlighted some of the benefits of car pooling but was limited to static routes with two riders per vehicle (optimally) or three (with heuristics). We present a more general mathematical model for real-time high-capacity ride-sharing that (i) scales to large numbers of passengers and trips and (ii) dynamically generates optimal routes with respect to online demand and vehicle locations. The algorithm starts from a greedy assignment and improves it through a constrained optimization, quickly returning solutions of good quality and converging to the optimal assignment over time. We quantify experimentally the tradeoff between fleet size, capacity, waiting time, travel delay, and operational costs for low- to medium-capacity vehicles, such as taxis and van shuttles. The algorithm is validated with ∼3 million rides extracted from the New York City taxicab public dataset. Our experimental study considers ride-sharing with rider capacity of up to 10 simultaneous passengers per vehicle. The algorithm applies to fleets of autonomous vehicles and also incorporates rebalancing of idling vehicles to areas of high demand. This framework is general and can be used for many real-time multivehicle, multitask assignment problems.

Risky riding behavior on two wheels: the role of cognitive, social, and personality variables among young adolescents.

Science.gov (United States)

Falco, Alessandra; Piccirelli, Alessandra; Girardi, Damiano; Dal Corso, Laura; De Carlo, Nicola A

2013-09-01

The main objective of this study was to analyze and estimate the relations between risky riding behaviors and some personality and sociocognitive variables through structural equation modeling. We focused on two-wheel riding behavior among a sample of 1,028 Italian adolescents at their first driving experience. The main findings confirmed the role of personality in influencing riding behavior directly as well as indirectly through risk perception. In particular, risk perception was a significant mediator between personality, social norm, and riding behavior. The significant relations that emerged in the general sample were further confirmed in the two specific sub-samples of males and females. In terms of social marketing and educational communication, it may consequently be advisable to proceed in an integrated and coordinated manner at both the cognitive and social level, taking into account some "dispositions to risk" related to personality. The integrated and coordinated action on different levels--cognitive, social, and personality--may therefore allow more effective and significant results in reducing those risky riding behaviors that often underlie young two-wheel riders' higher involvement in traffic accidents. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

Barriers and solutions for AC low voltage fault ride-through on multi-terminal HVDC grids

Energy Technology Data Exchange (ETDEWEB)

Silva, B.; Moreira, C.L.; Leite, H.; Pecas Lopes, J.A. [Porto Univ. (Portugal). Dept. de Engenharia Electrotecnica e de Computadores (DEEC); Tecnologia e Ciencia, Porto (Portugal). Inst. de Engenharia de Sistemas e Computadores (INESCTEC)

2012-07-01

This work analyzes the multi-terminal DC grids dynamics under AC mainland grid fault events envisioning to assess the feasibility of fault ride-through provision. The major bottleneck related with the operation under AC fault consists on the DC side power imbalance that takes place due to the HVDC converter current limits and consequent incapability of delivering all the generated power to the grid. It was also verified that the power imbalance leads to a DC overvoltage occurrence. The mechanism of including chopper devices at the onshore converters DC terminals has been studied as a mean of power equilibrium promotion. Simulations comparing the both cases were performed and the comparison and the effectiveness of the adopted approach are also presented. (orig.)

Examination of fault ride-through methods for off-shore wind farms connected to the grid through VSC-based HVDC transmission

Energy Technology Data Exchange (ETDEWEB)

Karaagac, U.; Mahseredjian, J.; Saad, H. [Ecole Polytechnique de Montreal, QC (Canada); Jensen, S.; Cai, L. [REpower Systems AG, Hamburg (Germany)

2012-07-01

The fault ride-through (FRT) performance of offshore wind farms (OWFs) is a challenging task when the OWF is connected to the onshore ac grid through a voltage source converter (VSC) based HVDC transmission system. The injected power from the OWF cannot be reduced by the offshore VSC during onshore ac faults and this causes a fast increase in the dc network voltage. Without any special FRT method, the dc network voltage may increase up to intolerable levels and cause operation of dc overvoltage protection. This paper compares various FRT methods based on fast reduction of power generation in OWFs. In addition, this paper proposes an improved FRT method based on controlled voltage drop for output power reduction in OWFs. The proposed improvement reduces mechanical stress on the wind turbine (WT) drive train, and electrical stress on the insulated gate bipolar transistors (IGBTs) of the HVDC and doubly-fed induction generator (DFIG) converters. Practical onshore ac fault scenarios are simulated for an OWF composed of DFIG type WTs and connected to a practical ac grid through a point-to-point modular multilevel converter (MMC) based HVDC system. (orig.)

Fault ride-through and grid support of permanent magnet synchronous generator-based wind farms with HVAC and VSC-HVDC transmission systems

DEFF Research Database (Denmark)

Liu, Hongzhi; Chen, Zhe

2012-01-01

This paper describes fault ride-through and grid support of offshore wind farms based on permanent magnet synchronous generator (PMSG) wind turbines connected to the onshore AC network through two alternative transmission systems: high voltage AC (HVAC) or high voltage DC (HVDC) based on voltage...... source converters (VSC). The proposed configurations of the PMSG-based offshore wind farm and VSC-based HVDC are given as well as their control strategies under both steady state and fault state. The PMSG-based offshore wind farm is integrated into a test power transmission system via either HVAC or VSC...

Stability of a Light Sail Riding on a Laser Beam

Energy Technology Data Exchange (ETDEWEB)

Manchester, Zachary [John A. Paulson School of Engineering and Applied Science, Harvard University, 60 Oxford St., Cambridge, MA 02138 (United States); Loeb, Abraham, E-mail: zmanchester@seas.harvard.edu [Astronomy Department, Harvard University, 60 Garden St., Cambridge, MA 02138 (United States)

2017-03-10

The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable without active control or additional mechanical modifications. A new architecture for a passively stable sail-and-beam configuration is proposed. The novel spherical shell design for the sail is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

Stability of a Light Sail Riding on a Laser Beam

International Nuclear Information System (INIS)

Manchester, Zachary; Loeb, Abraham

2017-01-01

The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable without active control or additional mechanical modifications. A new architecture for a passively stable sail-and-beam configuration is proposed. The novel spherical shell design for the sail is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

Feasibility testing for dial-a-ride problems

DEFF Research Database (Denmark)

Haugland, Dag; Ho, Sin C.

Hunsaker and Savelsbergh have proposed an algorithm for testing feasibility of a route in the solution to the dial-a-ride problem. The constraints that are checked are load capacity constraints, time windows, ride time bounds and wait time bounds. The algorithm has linear running time. By virtue...

Feasibility Testing for Dial-a-Ride Problems

DEFF Research Database (Denmark)

Haugland, Dag; Ho, Sin C.

2010-01-01

Hunsaker and Savelsbergh have proposed an algorithm for testing feasibility of a route in the solution to the dial-a-ride problem. The constraints that are checked are load capacity constraints, time windows, ride time bounds and wait time bounds. The algorithm has linear running time. By virtue...

High performance AC–DC control power supply for low voltage ride ...

Indian Academy of Sciences (India)

Ride-Through (LVRT) in solar and wind applications, no work has been ... section 5. Figure 2. Schematic structure of a control power supply used in a HPC. ..... order plant transfer function to first order transfer function. Also, peak current ...

Enhancing the Strategic Capability of the Army: An Investigation of Strategic Thinking Tasks, Skills, and Development

Science.gov (United States)

2016-02-01

Army assignments. Teaching can also help develop visualization skills and innovative thinking through the use of certain teaching methods...required. Some of the specific strategic thinking KSAs built through exposure to complex problems that were mentioned in the interviews were visualization ...Research Report 1995 Enhancing the Strategic Capability of the Army: An Investigation of Strategic Thinking Tasks, Skills

The enhancements and testing for the MCNPX depletion capability

International Nuclear Information System (INIS)

Fensin, M. L.; Hendricks, J. S.; Anghaie, S.

2008-01-01

Monte Carlo-linked depletion methods have gained recent interest due to the ability to more accurately model true system physics and better track the evolution of temporal nuclide inventory by simulating the actual physical process. The integration of INDER90 into the MCNPX Monte Carlo radiation transport code provides a completely self-contained Monte- Carlo-linked depletion capability in a single Monte Carlo code that is compatible with most nuclear criticality (KCODE) particle tracking features in MCNPX. MCNPX depletion tracks all necessary reaction rates and follows as many isotopes as cross section data permits in order to achieve a highly accurate temporal nuclide inventory solution. We describe here the depletion methodology dating from the original linking of MONTEBURNS and MCNP to the first public release of the integrated capability (MCNPX 2. 6.B, June, 2006) that has been reported previously. Then we further detail the many new depletion capability enhancements since then leading to the present capability. The H.B. Robinson benchmark calculation results are also reported. The new MCNPX depletion capability enhancements include: (1) allowing the modeling of as large a system as computer memory capacity permits; (2) tracking every fission product available in ENDF/B VII. 0; (3) enabling depletion in repeated structures geometries such as repeated arrays of fuel pins; (4) including metastable isotopes in burnup; and (5) manually changing the concentrations of key isotopes during different time steps to simulate changing reactor control conditions such as dilution of poisons to maintain criticality during burnup. These enhancements allow better detail to model the true system physics and also improve the robustness of the capability. The H.B. Robinson benchmark calculation was completed in order to determine the accuracy of the depletion solution. Temporal nuclide computations of key actinide and fission products are compared to the results of other

Spine fractures caused by horse riding

OpenAIRE

Siebenga, Jan; Segers, Michiel J. M.; Elzinga, Matthijs J.; Bakker, Fred C.; Haarman, Henk J. T. M.; Patka, Peter

2006-01-01

Study Design: Retrospective study and review of literature. Objectives: Study of demographic data concerning spinal fractures caused by horse riding, classification of fractures according to the AO and Load Sharing classifications, evaluation of mid-term radiological results and long-term functional results. Methods: A review of medical reports and radiological examinations of patients presented to our hospital with horse riding-related spine fractures over a 13-year period; long-term functio...

Control Strategy of Three-Phase Photovoltaic Inverter under Low-Voltage Ride-Through Condition

Directory of Open Access Journals (Sweden)

Xianbo Wang

2015-01-01

Full Text Available The new energy promoting community has recently witnessed a surge of developments in photovoltaic power generation technologies. To fulfill the grid code requirement of photovoltaic inverter under low-voltage ride-through (LVRT condition, by utilizing the asymmetry feature of grid voltage, this paper aims to control both restraining negative sequence current and reactive power fluctuation on grid side to maintain balanced output of inverter. Two mathematical inverter models of grid-connected inverter containing LCL grid-side filter under both symmetrical and asymmetric grid are proposed. PR controller method is put forward based on inverter model under asymmetric grid. To ensure the stable operation of the inverter, grid voltage feedforward method is introduced to restrain current shock at the moment of voltage drop. Stable grid-connected operation and LVRT ability at grid drop have been achieved via a combination of rapid positive and negative sequence component extraction of accurate grid voltage synchronizing signals. Simulation and experimental results have verified the superior effectiveness of our proposed control strategy.

Braking Control for Improving Ride Comfort

Directory of Open Access Journals (Sweden)

Lee Jonghyup

2018-01-01

Full Text Available While many vehicle control systems focus on vehicle safety and vehicle performance at high speeds, most driving conditions are very low risk situations. In such a driving situation, the ride comfort of the vehicle is the most important performance index of the vehicle. Electro mechanical brake (EMB and other brake-by-wire (BBW systems have been actively researched. As a result, braking actuators in vehicles are more freely controllable, and research on improving ride comfort is also possible. In this study, we develop a control algorithm that dramatically improves ride comfort in low risk braking situations. A method for minimizing the inconvenience of a passenger due to a suddenly changing acceleration at the moment when the vehicle is stopped is presented. For this purpose, an acceleration trajectory is generated that minimizes the discomfort index defined by the change in acceleration, jerk. A controller is also designed to track this trajectory. The algorithm that updates the trajectory is designed considering the error due to the phase lag occurring in the controller and the plant. In order to verify the performance of this controller, simulation verification is completed using a car simulator, Carsim. As a result, it is confirmed that the ride comfort is dramatically improved.

Minimum Makespan Multi-Vehicle Dial-a-Ride

DEFF Research Database (Denmark)

Gørtz, Inge Li; Nagarajan, Viswanath; Ravi, R.

2015-01-01

of multi-vehicle Dial-a-Ride, in which an object may be left at intermediate vertices and transported by more than one vehicle, while being moved from source to destination. Our main results are an O(log(3) n)-approximation algorithm for preemptive multi-vehicle Dial-a-Ride, and an improved O(log t...

Injuries associated with the use of riding mowers in the United States, 2002-2007.

Science.gov (United States)

Hammig, Bart; Childers, Elizabeth; Jones, Ches

2009-10-01

To examine injuries among patients treated in an emergency department (ED) related to the use of a riding lawn mower. Data were obtained from the National Electronic Injury Surveillance System for the years 2002-2007. National estimates of ED visits for injuries associated with the use of a riding lawn mower were analyzed. Narrative text entries were categorized to provide a detailed record of the circumstances precipitating the injury. Average annual rates were calculated and logistic regression analyses were employed to determine risk estimates for patient disposition and demographic characteristics related to ED visits for injuries associated with riding mowers. From 2002 through 2007, there were an estimated 66,341 ED visits for injuries related to the use of riding lawnmowers in the U.S., with an average annual rate of 6.0 ED visits per 100,000 males, and 1.6 ED visits per 100,000 females. Older adults had higher rates of ED visits for injuries (7.2/100,000) than younger age groups. The most common injuries involved contusions (24%); sprains/strains (22%) and fractures (17%). The majority of patients (90%) were treated and released the same day. Results of logistic regression analyses revealed that older adults were more likely to be hospitalized when compared to younger age groups; and incidents involving rollovers [OR=5.45 (95% CI=3.22-9.23)] and being run over [6.01 (95% CI 3.23-11.17)] were more likely to result in hospitalization when compared to all other circumstances of injury. Riding mowers present injury patterns and circumstances that are different than those reported for push mowers. Circumstances related to injuries and age groups affected were varied, making prevention of riding mower injuries challenging. APPLICATION/IMPACT: Findings support the need to increase awareness and/or change the design of riding mowers with respect to risk of rollover injuries.

Core Capabilities and Technical Enhancement -- FY-98 Annual Report

Energy Technology Data Exchange (ETDEWEB)

Miller, David Lynn

1999-04-01

The Core Capability and Technical Enhancement (CC&TE) Program, a part of the Verification, Validation, and Engineering Assessment Program, was implemented to enhance and augment the technical capabilities of the Idaho National Engineering and Environmental Laboratory (INEEL). The purpose for strengthening the technical capabilities of the INEEL is to provide the technical base to serve effectively as the Environmental Management Laboratory for the Office of Environmental Management (EM). An analysis of EM's science and technology needs as well as the technology investments currently being made by EM across the complex was used to formulate a portfolio of research activities designed to address EM's needs without overlapping work being done elsewhere. An additional purpose is to enhance and maintain the technical capabilities and research infrastructure at the INEEL. This is a progress report for fiscal year 1998 for the five CC&TE research investment areas: (a) transport aspects of selective mass transport agents, (b) chemistry of environmental surfaces, (c) materials dynamics, (d) characterization science, and (e) computational simulation of mechanical and chemical systems. In addition to the five purely technical research areas, this report deals with the science and technology foundations element of the CC&TE from the standpoint of program management and complex-wide issues. This report also provides details of ongoing and future work in all six areas.

Core capabilities and technical enhancement, FY-98 annual report

Energy Technology Data Exchange (ETDEWEB)

Miller, D.L.

1999-04-01

The Core Capability and Technical Enhancement (CCTE) Program, a part of the Verification, Validation, and Engineering Assessment Program, was implemented to enhance and augment the technical capabilities of the Idaho National Engineering and Environmental Laboratory (INEEL). The purpose for strengthening the technical capabilities of the INEEL is to provide the technical base to serve effectively as the Environmental Management Laboratory for the Department of Energy's Office of Environmental Management (EM). An analysis of EM's science and technology needs as well as the technology investments currently being made by EM across the complex was used to formulate a portfolio of research activities designed to address EM's needs without overlapping work being done elsewhere. An additional purpose is to enhance and maintain the technical capabilities and research infrastructure at the INEEL. This is a progress report for fiscal year 1998 for the five CCTE research investment areas: (a) transport aspects of selective mass transport agents, (b) chemistry of environmental surfaces, (c) materials dynamics, (d) characterization science, and (e) computational simulation of mechanical and chemical systems. In addition to the five purely technical research areas, this report deals with the science and technology foundations element of the CCTE from the standpoint of program management and complex-wide issues. This report also provides details of ongoing and future work in all six areas.

Flexible fault ride through of DFIG wind turbines with DC-chopper solution

Energy Technology Data Exchange (ETDEWEB)

Wessels, Christian; Laubrock, Malte; Bellgardt, Uwe [Nordex Energy GmbH, Hamburg (Germany). System Dept Grid and Grid Integration; Genius, Andreas [Woodward Kempen GmbH, Kempen (Germany). Wind Power Systems

2012-07-01

Grid code requirements are becoming increasingly challenging due to the growing integration of decentralized power generators like renewable energy devices. One of the most challenging grid code requirements is the fault ride through (FRT) of wind turbines. Internationally varying and quickly revised grid code requirements are making it necessary for wind turbine manufacturers to apply competitive hardware and flexible software structures to respond quickly to renewed requirements or project specific changes. In this paper an industrially applied and field-tested hardware solution for the FRT of a DFIG wind turbine is presented. The method using a DC-chopper is making the utilization of the conventionally used rotor crowbar unnecessary. Thus, the consumption of reactive power during grid faults is avoided. Instead, a controlled current can be fed dynamically in order to support the grid voltage and to avoid mechanical stress on the drivetrain of the turbine. Using the presented technology, the application of a flexible FRT software structure is possible to fulfill the internationally varying FRT requirements, which is described here. Selected measurement results from long term FRT tests from a wind turbine manufacturer of a real 2.5 MW wind turbine during grid faults are presented and verify the results. (orig.)

A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

DEFF Research Database (Denmark)

You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

2013-01-01

This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability...... and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine...

EFFECT OF FAMILY EMPOWERMENT IN ENHANCING THE CAPABILITIES OF CHILDREN WITH AUTISM

Directory of Open Access Journals (Sweden)

Suprajitno

2017-10-01

Full Text Available Background: Children with autism as individuals have a right to receive developmental needs obtained from parent/caregiver during their stay in the family. The family ability can be improved through empowerment training to provide stimulation for the development of children with autism. Objective: This study aims examine the effect of family empowerment in enhancing the capabilities of children with autism. Methods: The research design used a two-stage quasi-experiment. The first stage was a training for parent/caregiver of children with autism using modules. Training was done three times in the Autism Service Center (PLA of Blitar City. The second stage was the parent/caregiver provided stimulation to their children at home. There were 33 children selected using total sampling in the PLA of Blitar City on April – August, 2016. Data were analyzed using descriptive statistics and paired t-test. Results: The family ability to stimulate the capability of children with autism in the sense of hearing, vision, motoric, and inviting to play obtained average changes of 61.99%, with average items increased from 18.52 to 30.00. While the increase capabilities of children with autism were categorized into five classification: communication, fulfilling of activity daily living, language-numbers–tactile, psychology, and understanding commands. Conclusion: There was a significant effect of family empowerment in enhancing the capabilities of children with autism. Thus, training to improve the ability of parent/caregiver in caring children with autism needs to be implemented in a planned and gradually manner.

Investigation on Motorcyclist Riding Behaviour at Curve Entry Using Instrumented Motorcycle

Science.gov (United States)

Yuen, Choon Wah; Karim, Mohamed Rehan; Saifizul, Ahmad

2014-01-01

This paper details the study on the changes in riding behaviour, such as changes in speed as well as the brake force and throttle force applied, when motorcyclists ride over a curve section road using an instrumented motorcycle. In this study, an instrumented motorcycle equipped with various types of sensors, on-board cameras, and data loggers, was developed in order to collect the riding data on the study site. Results from the statistical analysis showed that riding characteristics, such as changes in speed, brake force, and throttle force applied, are influenced by the distance from the curve entry, riding experience, and travel mileage of the riders. A structural equation modeling was used to study the impact of these variables on the change of riding behaviour in curve entry section. Four regression equations are formed to study the relationship between four dependent variables, which are speed, throttle force, front brake force, and rear brake force applied with the independent variables. PMID:24523660

Negative Sequence Droop Method based Hierarchical Control for Low Voltage Ride-Through in Grid-Interactive Microgrids

DEFF Research Database (Denmark)

Zhao, Xin; Firoozabadi, Mehdi Savaghebi; Quintero, Juan Carlos Vasquez

2015-01-01

. In this paper, a voltage support strategy based on negative sequence droop control, which regulate the positive/negative sequence active and reactive power flow by means of sending proper voltage reference to the inner control loop, is proposed for the grid connected MGs to ride through voltage sags under...... complex line impedance conditions. In this case, the MGs should inject a certain amount of positive and negative sequence power to the grid so that the voltage quality at load side can be maintained at a satisfied level. A two layer hierarchical control strategy is proposed in this paper. The primary...... control loop consists of voltage and current inner loops, conventional droop control and virtual impedance loop while the secondary control loop is based on positive/negative sequence droop control which can achieve power injection under voltage sags. Experimental results with asymmetrical voltage sags...

COMPETITIVE INTELLIGENCE: THE ENHANCING ROLE OF ORGANIZATIONAL LEARNING CAPABILITY

OpenAIRE

HAMAD, Zaina Mustafa Mahmoud; YOZGAT, Ugur

2017-01-01

Performinga strong intelligence grants an organization a guaranteeof long-term success. This paper investigates the enhancing effect of organizational learning capabilities on competitive intelligence atthe commercial banks in Jordan. A sample within top and middle managements was used.Measurement instrument validity and model fit were assessed before testinghypotheses. This study emphasizes the role learning capability plays inenhancing intelligence. Key findings support importance of organi...

The Orphee reactor current status and proposed enhancement of experimental capabilities

International Nuclear Information System (INIS)

Breant, P.

1990-01-01

This report provides a description of the Orphee reactor, together with a rapid assessment of its experimental and research capabilities. The plans for enhancing the reactor's experimental capabilities are also presented. (author)

Healthy Ride Trip Data

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — A dataset that shows trips taken using the Healthy Ride system by quarter. The dataset includes bike number, membership type, trip start and end timestamp, and...

A guideline for interpersonal capabilities enhancement to support sustainable facility management practice

Science.gov (United States)

Sarpin, Norliana; Kasim, Narimah; Zainal, Rozlin; Noh, Hamidun Mohd

2018-04-01

Facility management is the key phase in the development cycle of an assets and spans over a considerable length of time. Therefore, facility managers are in a commanding position to maximise the potential of sustainability through the development phases from construction, operation, maintenance and upgrade leading to decommission and deconstruction. Sustainability endeavours in facility management practices will contribute to reducing energy consumption, waste and running costs. Furthermore, it can also help in improving organisational productivity, financial return and community standing of the organisation. Facility manager should be empowered with the necessary knowledge and capabilities at the forefront facing sustainability challenge. However, literature studies show a gap between the level of awareness, specific knowledge and the necessary skills required to pursue sustainability in the facility management professional. People capability is considered as the key enabler in managing the sustainability agenda as well as being central to the improvement of competency and innovation in an organisation. This paper aims to develop a guidelines for interpersonal capabilities to support sustainability in facility management practice. Starting with a total of 7 critical interpersonal capabilities factors identified from previous questionnaire survey, the authors conducted an interview with 3 experts in facility management to assess the perceived importance of these factors. The findings reveal a set of guidelines for the enhancement of interpersonal capabilities among facility managers by providing what can be done to acquire these factors and how it can support the application of sustainability in their practice. The findings of this paper are expected to form the basis of a mechanism framework developed to equip facility managers with the right knowledge, to continue education and training and to develop new mind-sets to enhance the implementation of sustainability

Pediatric fractures during skateboarding, roller skating, and scooter riding.

Science.gov (United States)

Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

2005-04-01

Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

Grid support capabilities of wind turbines

DEFF Research Database (Denmark)

Michalke, Gabriele; Hansen, Anca Daniela

2013-01-01

Wind power has gained a significant penetration level in several power systems all over the world. Due to this reason modern wind turbines are requested to contribute to power system support. Power system operators have thus introduced grid codes, which specify a set of requirements for wind...... turbines, such as fault ride-through and reactive power supply during voltage sags. To date different wind turbine concepts exist on the market comprising different control features in order to provide ancillary services to the power system. In the first place the present chapter emphasizes the most...... important issues related to wind power grid integration. Then different wind turbine concepts are characterized and their grid support capabilities are analysed and compared. Simulation cases are presented in which the respective wind turbine concepts are subjected to a voltage dip specified in a grid code....

A Coordinated LVRT Control for a PMSG Wind Turbine

DEFF Research Database (Denmark)

Kim, Chunghun; Gui, Yonghao; Chung, Chung Choo

2017-01-01

This paper proposes a coordinated controller for a permanent-magnet synchronous generator wind turbine to enhance its low voltage ride through capability. In the proposed method, both rotor side and grid side converters are cooperatively controlled to regulate the DC link voltage during the grid...

The social context of motorcycle riding and the key determinants influencing rider behavior: a qualitative investigation.

Science.gov (United States)

Tunnicliff, Deborah; Watson, Barry; White, Katherine M; Lewis, Ioni; Wishart, Darren

2011-08-01

Given the increasing popularity of motorcycle riding and heightened risk of injury or death associated with being a rider, this study explored rider behavior as a determinant of rider safety and, in particular, key beliefs and motivations that influence such behavior. To enhance the effectiveness of future education and training interventions, it is important to understand riders' own views about what influences how they ride. Specifically, this study sought to identify key determinants of riders' behaviors in relation to the social context of riding, including social and identity-related influences relating to the group (group norms and group identity) as well as the self (moral/personal norm and self-identity). Qualitative research was undertaken via group discussions with motorcycle riders (n = 41). The findings revealed that those in the group with which one rides represent an important source of social influence. Also, the motorcyclist (group) identity was associated with a range of beliefs, expectations, and behaviors considered to be normative. Exploration of the construct of personal norm revealed that riders were most cognizant of the "wrong things to do" when riding; among those issues raised was the importance of protective clothing (albeit for the protection of others and, in particular, pillion passengers). Finally, self-identity as a motorcyclist appeared to be important to a rider's self-concept and was likely to influence on-road behavior. Overall, the insight provided by the current study may facilitate the development of interventions including rider training as well as public education and mass media messages. The findings suggest that these interventions should incorporate factors associated with the social nature of riding in order to best align it with some of the key beliefs and motivations underpinning riders' on-road behaviors.

ReRide: Performing Lower Back Rehabilitation While Riding Your Motorbike in Traffic

DEFF Research Database (Denmark)

Bagalkot, Naveen; Sokoler, Tomas; Baadkar, Suraj

2016-01-01

controlled mechanically moving display mounted on top of the bike's speedometer that alters the visibility of the speedometer to the rider indicating the correctness of back posture. Informed by embodied perception, the ReRide design emphasizes a rapid coupling between adjusting your back posture...

Never Riding the Tide

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 10. Never Riding the Tide - Seymour Benzer–The Founder of Neurogenetics. K VijayRaghavan Veronica Rodrigues. General Article Volume 13 Issue 10 October 2008 pp 909-915 ...

Examination of a University-Affiliated Safe Ride Program

Science.gov (United States)

Gieck, D. Joseph; Slagle, David M.

2010-01-01

A university-affiliated safe ride program was evaluated to determine whether these programs can reduce drunk-driving related costs. Data was collected from 187 safe ride passengers during three nights of operation. Among the passengers, 93% were enrolled at a local University, 31% were younger than 21, and 40% reported a prior alcohol-related…

Investor Behavior and Flow-Through Capability in the US Stock Market

Directory of Open Access Journals (Sweden)

Carlos eCano

2016-05-01

Full Text Available This paper analyzes investor behavior depending on the flow-through capability in the US stock market, because investors seek protection from inflation rate changes, and the flow-through capability (a firm’s ability to transmit inflation shocks to the prices of its products and services is a key factor in investment decisions. Our estimates of the flow-through capability of firms listed on the US stock exchange at the sector level are significantly different among industries, and we demonstrate a direct relationship between changes in stock prices (at the sector level and flow-through capability. These results would be relevant because they have important implications on investor behavior.

Maintaining stability of standalone Micro-Grid by employing electrical and mechanical fault ride through techniques upon fixed speed wind generation systems

International Nuclear Information System (INIS)

Kamel, Rashad M.

2013-01-01

Highlights: • This paper presented two fault ride through techniques for fixed speed wind systems. • The first technique is implemented by inserting a series resistance with the terminals of wind generator. • Second technique is performed by adapting the gear ratio to spill some mechanical power. - Abstract: This study presents two different Fault Ride Through (FRT) techniques to keep and restore stability of Fixed Speed Wind Generation system (FSWGs) installed in standalone Micro-Grid (MG). The first technique is an electrical FRT and is implemented by inserting a series resistance with the terminals of FSWGs during fault to maintain reasonable value of terminal voltage and consequently help stability restoration. The second controller is a mechanical FRT controller and is performed by change the gear ratio of wind generation systems to spill part of extracted mechanical power and consequently improving stability issue. Obtained results proved that each controller able to maintain the stability of FSWGs under the most severe disturbance conditions (400 ms three phase fault at FSWGs terminals). The first controller is faster than the second controller in restoring FSWGs stability. Superior results and performances are obtained when the two FRT techniques are employed simultaneously. Without employing any one of the two FRT techniques, FSWGs is not able to maintain or restore its stability after fault clearing. Consequently, MG will lose one of its micro-sources and cannot keep its stability during the standalone mode, unless load shedding strategy is activated. The two proposed controllers are simple, effective, and economical attractive

Riding through red lights: the rate, characteristics and risk factors of non-compliant urban commuter cyclists.

Science.gov (United States)

Johnson, Marilyn; Newstead, Stuart; Charlton, Judith; Oxley, Jennifer

2011-01-01

This study determined the rate and associated factors of red light infringement among urban commuter cyclists. A cross-sectional observational study was conducted using a covert video camera to record cyclists at 10 sites across metropolitan Melbourne, Australia from October 2008 to April 2009. In total, 4225 cyclists faced a red light and 6.9% were non-compliant. The main predictive factor for infringement was direction of travel, cyclists turning left (traffic travels on the left-side in Australia) had 28.3 times the relative odds of infringement compared to cyclists who continued straight through the intersection. Presence of other road users had a deterrent effect with the odds of infringement lower when a vehicle travelling in the same direction was present (OR=0.39, 95% CI 0.28-0.53) or when other cyclists were present (OR=0.26, 95% CI 0.19-0.36). Findings suggest that some cyclists do not perceive turning left against a red signal to be unsafe and the opportunity to ride through the red light during low cross traffic times influences the likelihood of infringement. Copyright © 2010 Elsevier Ltd. All rights reserved.

Measurements of Wake-Riding Electrons in Antiproton-Carbon-Foil Collisions

CERN Multimedia

2002-01-01

When a charged particle passes through dielectric media, e.g. a thin carbon foil, a ``wake'' is induced. The characteristic wake-potential shows an oscillatory behaviour, with a wavelength of about $ 2 \\pi v _{p} / \\omega _{p} _{l} $ where $ v _{p} $ is the projectile velocity and $ \\omega _{p} _{l} $ the plasmon energy of the target. This induced wake potential is superimposed on the Coulomb potential of the projectile, the latter leading to a pronounced ``cusp'' of electrons leaving the solid at $ v _{e} app v _{p} $ for positively charged projectiles in the MeV region. Correspondingly, an ``anti-cusp'' is expected for antiprotons. \\\\ \\\\ In the solid, the wake-potential leads to an attractive force on electrons, and a dynamic electronic state is predicted both for proton and antiproton projectiles. In the solid, the wake-riding electrons are travelling with the projectile speed $ v _{p} $ Upon exit of the foil, the electron released from the wake-riding state of an antiproton will suddenly find itself in th...

Coordinated Control Strategies of VSC-HVDC-Based Wind Power Systems for Low Voltage Ride Through

Directory of Open Access Journals (Sweden)

Xinyin Zhang

2015-07-01

Full Text Available The Voltage Source Converter-HVDC (VSC-HVDC system applied to wind power generation can solve large scale wind farm grid-connection and long distance transmission problems. However, the low voltage ride through (LVRT of the VSC-HVDC connected wind farm is a key technology issue that must be solved, and it is currently lacking an economic and effective solution. In this paper, a LVRT coordinated control strategy is proposed for the VSC-HVDC-based wind power system. In this strategy, the operation and control of VSC-HVDC and wind farm during the grid fault period is improved. The VSC-HVDC system not only provides reactive power support to the grid, but also effectively maintains the power balance and DC voltage stability by reducing wind-farm power output, without increasing the equipment investment. Correspondingly, to eliminate the influence on permanent magnet synchronous generator (PMSG-based wind turbine (WT systems, a hierarchical control strategy is designed. The speed and validity of the proposed LVRT coordinated control strategy and hierarchical control strategy were verified by MATLAB/Simulink simulations.

Economic analysis of the organisation of a riding centre; application of the linear programming approach

Directory of Open Access Journals (Sweden)

Jaka ŽGAJNAR

2015-12-01

Full Text Available In this contribution, the economics of an equestrian centre, which in addition to a variety of riding school activities also includes breeding and livery, are analysed. We consider the conditions for a hypothetical holding operating in central Slovenia. Methods of mathematical programming are applied in order to attempt to optimise the holding’s activities. Their use may in the given situation facilitate the evaluation of development prospects from different perspectives and indicate the opportunities of increasing value-added. On the basis of maximizing the gross margin, we try to address the various questions and challenges that arise in managing and planning for such an equestrian centre. The obtained results indicate that breeding is unfavourable in the given price-cost ratio, both for the renewal of the working horses herd and for sale. This reflects the current adverse situation in the field of horse breeding. Livery is an important activity on such holdings and through opportunity perspective provides an optimal set of activities. Activities of the riding school for children are interesting in terms of income diversification, as well as an additional source of revenue. A riding school with one riding instructor and an indoor arena needs 4.6 horses in order to cover the costs of full-time employment.

Vision-based measuring system for rider's pose estimation during motorcycle riding

Science.gov (United States)

Cheli, F.; Mazzoleni, P.; Pezzola, M.; Ruspini, E.; Zappa, E.

2013-07-01

Inertial characteristics of the human body are comparable with the vehicle ones in motorbike riding: the study of a rider's dynamic is a crucial step in system modeling. An innovative vision based system able to measure the six degrees of freedom of the driver with respect to the vehicle is proposed here: the core of the proposed approach is an image acquisition and processing technique capable of reconstructing the position and orientation of a target fixed on the rider's back. The technique is firstly validated in laboratory tests comparing measured and imposed target motion laws and successively tested in a real case scenario during track tests with amateur and professional drivers. The presented results show the capability of the technique to correctly describe the driver's dynamic, his interaction with the vehicle as well as the possibility to use the new measuring technique in the comparison of different driving styles.

Enhanced Monte-Carlo-Linked Depletion Capabilities in MCNPX

International Nuclear Information System (INIS)

Fensin, Michael L.; Hendricks, John S.; Anghaie, Samim

2006-01-01

. These capabilities have been enhanced by the two major new improvements described here. Further improvements are under development to enhance the usefulness of this new capability. (authors)

Knowledge Management for Enhancing Regulatory Body Capabilities in Thailand

International Nuclear Information System (INIS)

Apichaibukol, A.; Pakdee, K.

2016-01-01

Full text: In order to be a learning organization, the Office of Atoms for Peace (OAP) has appointed a knowledge-management team in an attempt to manage internal knowledge, both tacit knowledge and explicit knowledge, systematically. In principle, the seven steps of knowledge management will be applied for OAP KM, namely; 1. Knowledge identification including the knowledge required of the Regulatory Body. 2. Knowledge creation and acquisition including knowledge sharing, transfer and how to maintain knowledge external factors such as a customers, stakeholder, etc. 3. Knowledge organization based on knowledge structure is needed for a systematic knowledge retention in the future. 4. Knowledge refinement with ISO standards in document storage. 5. Knowledge access for example, using information technology management through web board. 6. Knowledge sharing, OAP staff through numerous methods designed to transfer implicit and tacit knowledge such as formal classroom and on-the-job training, informal Communities of Practice, mentoring. 7. Learning is OAP group continually enhancing their capabilities and making decisions, solving problems and improving the organization. OAP staff could apply knowledge for organization development and planning for a supporting guideline. (author

Analyzing Forces on Amusement Park Rides with Mobile Devices

Science.gov (United States)

Vieyra, Rebecca E.; Vieyra, Chrystian

2014-01-01

Mobile device accelerometers are a simple and easy way for students to collect accurate and detailed data on an amusement park ride. The resulting data can be graphed to assist in the creation of force diagrams to help students explain their physical sensations while on the ride. This type of activity can help students overcome some of the…

Influences of Carbody Vertical Flexibility on Ride Comfort of Railway Vehicles

Directory of Open Access Journals (Sweden)

Dumitriu Mădălina

2017-06-01

Full Text Available The article investigates the influence of the carbody vertical flexibility on the ride comfort of the railway vehicles. The ride comfort is evaluated via the comfort index calculated in three reference points of the carbody. The results of the numerical simulations bring attention to the importance of the carbody symmetrical vertical bending upon the dynamic response of the vehicle, mainly at high velocities. Another conclusion is that the ride comfort can be significantly affected as a function of the symmetrical bending frequency of the carbody. Similarly, there are improvement possibilities for the ride comfort when the best selection of the stiffness in the longitudinal traction system between the carbody and bogie and the vertical suspension damping is made.

Stakeholder Capability Enhancement as a Path to Promote Human Dignity and Cooperative Advantage

NARCIS (Netherlands)

Westermann-Behaylo, M.K.; Van Buren III, H.J.; Berman, S.L.

2016-01-01

Promoting dignity is at the heart of the human capability approach to development. We introduce the concept of stakeholder capability enhancement, beginning with a discussion of the capability approach to development proposed by Sen (1985) and further advanced by Nussbaum (1990) to incorporate

Supernetwork approach for modeling traveler response to park-and-ride

NARCIS (Netherlands)

Liao, F.; Arentze, T.A.; Timmermans, H.J.P.

2012-01-01

Park-and-ride has been identified by transport planners as a key element of any sustainability package to promote multimodal trips, improve air quality, and alleviate congestion in urban areas. This paper presents a supernetwork approach that can assess traveler response to park-and-ride in an

Epidemiological pattern of motorcycle injuries with focus on riding purpose: Experience from a middle-income country

Directory of Open Access Journals (Sweden)

leili Abedi

2015-08-01

Full Text Available Introduction: Road traffic injuries are the eighth leading cause of death worldwide which usually occurs among people aged between15-29 years. In most LAMICs, half of fatal road traffic injuries occur among motorcyclists, which little is known about purpose of riding among motorcycle riders. Objectives: To map out epidemiological aspects of motorcycle traffic injuries with a focus on purpose of riding among victims admitted to referral centers, Tabriz, Iran. Materials/Patients and Methods: A descriptive study was carried out on 200 motorcycle traumatic patients admitted to Shohada and Imam Reza trauma centers in Tabriz((because these two hospitals are referral for trauma in East Azarbyjan Province, Iran from April till November 2013. A questionnaire was filled out through face to face interview for all subjects. Statistical analysis was done using Stata version 11. Results: All subjects were male with mean age of 29 years old. Among injured riders, 70% and 22% of them used helmet and had a riding license, respectively. About 23% of motorcycle riders stated that their main purpose of motorcycle riding was only for fun. Among motorcycle riders who used the motorcycle for fun purposes, the rate of helmet wearing was 43.5% versus 78% among those riding for other purposes (P 0.05; Odd ratio=1. 56, 95% CI: 0. 67-3.4. Crashes have happened more in the summer and during the afternoon times. Conclusion: Motorcyclists who rode motorcycles for fun and amusement, not having rider licenses and helmets wearing were less than other motorcycle riders. Since motorcyclists are mainly young, the rate of risky behavior in this group is higher. Therefore, it is suggested that young motorcycle riders who ride for fun, needs the priority for safety promotion intervention.

Enhancement Of Sensing Capabilities And Functionalization Of Optical Microresonators

Science.gov (United States)

Cocking, Alexander

of materials known as two dimensional materials (2D materials). Typically made from single atomic sheets of transition metal dichalcogenides, they are called two dimensional due to their incredibly small thickness. Monolayers of metal dichalcogenides offer large values for optical nonlinear susceptibility and can be used to generate highly efficient nonlinear optical phenomena. This chapter seeks to understand and describe the capabilities of these materials in a context of eventually integrating them into optical microresonators to create a new class of silica-based miniaturized nonlinear optical devices. The final chapter in this dissertation covers the proposed and in-progress work related to those topics already covered in previous chapters. This includes direct growth of transition metal dichalcogenides onto microsphere resonators to create narrow linewidth microscopic lasers. Another novel photonic device consists of a single mode optical fiber etched to expose the core onto which a monolayer of 2D material is adhered. This presents the capability to create a simple photonic device which can easily be integrated as a discrete optical component capable of producing guided photoluminescence or extremely high second harmonic generation. Finally, spectral holography is discussed as a potential tool to record the phase information of light traveling through optical microresonators, adhered particles, and directly grown 2D materials.

A participatory sensing approach to characterize ride quality

Science.gov (United States)

Bridgelall, Raj

2014-03-01

Rough roads increase vehicle operation and road maintenance costs. Consequently, transportation agencies spend a significant portion of their budgets on ride-quality characterization to forecast maintenance needs. The ubiquity of smartphones and social media, and the emergence of a connected vehicle environment present lucrative opportunities for cost-reduction and continuous, network-wide, ride-quality characterization. However, there is a lack of models to transform inertial and position information from voluminous data flows into indices that transportation agencies currently use. This work expands on theories of the Road Impact Factor introduced in previous research. The index characterizes road roughness by aggregating connected vehicle data and reporting roughness in direct proportion to the International Roughness Index. Their theoretical relationships are developed, and a case study is presented to compare the relative data quality from an inertial profiler and a regular passenger vehicle. Results demonstrate that the approach is a viable alternative to existing models that require substantially more resources and provide less network coverage. One significant benefit of the participatory sensing approach is that transportation agencies can monitor all network facilities continuously to locate distress symptoms, such as frost heaves, that appear and disappear between ride assessment cycles. Another benefit of the approach is continuous monitoring of all high-risk intersections such as rail grade crossings to better understand the relationship between ride-quality and traffic safety.

Scaling Law of Urban Ride Sharing

Science.gov (United States)

Tachet, R.; Sagarra, O.; Santi, P.; Resta, G.; Szell, M.; Strogatz, S. H.; Ratti, C.

2017-03-01

Sharing rides could drastically improve the efficiency of car and taxi transportation. Unleashing such potential, however, requires understanding how urban parameters affect the fraction of individual trips that can be shared, a quantity that we call shareability. Using data on millions of taxi trips in New York City, San Francisco, Singapore, and Vienna, we compute the shareability curves for each city, and find that a natural rescaling collapses them onto a single, universal curve. We explain this scaling law theoretically with a simple model that predicts the potential for ride sharing in any city, using a few basic urban quantities and no adjustable parameters. Accurate extrapolations of this type will help planners, transportation companies, and society at large to shape a sustainable path for urban growth.

Pensionäride probleemid jõuavad Euroopa Komisjoni / Arvo Einre ; interv. Asse Soomets

Index Scriptorium Estoniae

Einre, Arvo, 1931-2012

2005-01-01

Eesti Pensionäride Ühendus sai Euroopa Komisjoni eakate nõukojalt (The European Older People Platform) kutse 31. märtsil Brüsselis toimuvale AGE töökoosolekule, kus käsitletakse pensionäride olukorda EL-i liikmesriikides. Eesti esindajana sõidab üritusele Eesti Pensionäride Ühenduse aseesimees Arvo Einre

Assessment of control strategies for fault ride through of SCIG-based wind energy conversion systems

Directory of Open Access Journals (Sweden)

Manaullah

2016-01-01

Full Text Available With increasing penetration of wind energy into the power grid, researchers have started focusing more on control and coordination of wind energy conversion systems (WECS with the other components at system level, especially during fault. It is important to implement a suitable fault ride through control strategy to avoid tripping of the generators when the power system is subjected to voltage dips normally below 90% of nominal voltage. The dips below 90% may lead to a significant loss of generation and frequency collapse, followed by a blackout. This article implements and assesses the methodologies to deal with such situations for squirrel cage induction generator-based wind energy conversion systems employing fully rated power electronic converters. Three distinct control techniques—namely, balanced positive sequence control, positive negative sequence control, and dual current control—have been simulated and applied to grid side converter of SCIG-based WECS. The performance of all the three control strategies has been compared and presented in this work. During this study, the system is subjected to the most common unsymmetrical line to ground (LG fault and most severe symmetrical LLL fault on grid for the purpose of anaysis.

The directors’ roles in containing the Robben Island Diversity Experience (RIDE

Directory of Open Access Journals (Sweden)

Frans Cilliers

2012-03-01

Research purpose: The purpose of the research was to describe the experiences of the directors of RIDE in the last 10 years. Motivation for the study: Of the many and different diversity events that South African organisations present, RIDE is the only systems psycho-dynamically designed and presented event. This research was an effort to explore the nature of the directors’ roles in working with unconscious diversity dynamics in such a provocative venue. Research design, approach and method: The researchers conducted qualitative, descriptive and double hermeneutic research. The various RIDE events served as case studies. The data consisted of researcher field notes collected during the 10 years. Thematic analysis resulted in four themes, for which the researchers formulated working hypotheses. They integrated them into the research hypothesis. Main findings: Four themes emerged. They were the diversity characteristics of the directors as containers, working on the boundary between RIDE and the macro role players, attacks on the programme as container and challenges from participants. Practical/managerial implications: The research highlighted the important roles of directors’ authorisation as a resilience factor in containing RIDE. Contribution/value-add: The research contributed towards the awareness of intergroup relations between role players during diversity dynamic events and of how authorisation cements relationships.

A qualitative study of gender and work in a British riding school

OpenAIRE

Calamatta, Katherine F G

2012-01-01

This thesis focuses on employees of the horse riding school sector within the United Kingdom. It is based on qualitative fieldwork at two riding schools that took place over the course of three years and asks two questions: why do women numerically dominate within the setting of the riding school? How can we best understand this phenomenon using sociological literature? The subject for this thesis was motivated by my own prior experience as a worker within this industry.\\ud \\ud The thesis wil...

A Comparison Study on the Assessment of Ride Comfort for LRT Passengers

Science.gov (United States)

Tengku Munawir, Tengku Imran; Abqari Abu Samah, Ahmad; Afiq Akmal Rosle, Muhammad; Azlis-Sani, Jalil; Hasnan, Khalid; Sabri, S. M.; Ismail, S. M.; Yunos, Muhammad Nur Annuar Mohd; Yen Bin, Teo

2017-08-01

Ride comfort in railway transportation is very mind boggling and it relies on different dynamic performance criteria as well as subjective observation from the train passengers. Vibration discomfort from different elements such as vehicle condition, track area condition and working condition can prompt poor ride comfort. However, there are no universal applicable standards to analyse the ride comfort. There are several factors including local condition, vehicle condition and the track condition. In this current work, level of ride comfort by previous Adtranz-Walker light rapid transit (LRT) passengers at Ampang line were analysed. A comparison was done via two possible methods which are BS EN 12299 (2009) and Sperling’s Ride Index equation. BS EN 12299 standard is used to measure and evaluate the ride comfort of seating (Nvd) and standing (Nva) of train passenger in three different routes. Next, Sperling’s ride comfort equation is used to conduct validation and comparison between the obtained data. The result indicates a higher extent of vibration in the vertical axis which impacts the overall result. The standing position demonstrates a higher exposure of vibration in all the three tested routes. Comparison of the ride comfort assessment of passenger in sitting and standing position for both methods indicates that all the track sections exceeds “pronounced but not unpleasant (medium)” limit range. Nevertheless, the seating position at track section AU did not exceed the limit and stayed at the comfortable zone. The highest discomfort level achieved for both methods for seating position are 3.34 m/s2 for Nva and 2.63 m/s2 respectively, which is at route C uptrack that is from Chan Sow Lin station to Sri Petaling station. Meanwhile, the highest discomfort level achieved for both methods for standing are 3.80 m/s2 for Nvd and 2.88 m/s2 for Wz respectively, at uptrack section which is from Sri Petaling station to Chan Sow Lin station. Thus, the highest

Developing Capability and Agency through a Poverty-reduction ...

African Journals Online (AJOL)

Developing Capability and Agency through a Poverty-reduction Approach to ... Women in the Tswapong Region of Botswana depend on natural resources for their ... This work is licensed under a Creative Commons Attribution 3.0 License.

Hippotherapy and Therapeutic Riding Highlight!

Science.gov (United States)

Apel, Laura, Comp.

2007-01-01

Horses have always been appreciated by humans for their strength, beauty, and gentle demeanor. Children, especially, have gravitated toward them and many experience their first horseback riding lesson at a young age. However, horses can play a very different role in the lives of children and adults with disabilities. Hippotherapy is physical,…

Therapeutic Effects of Mechanical Horseback Riding on Gait and Balance Ability in Stroke Patients

Science.gov (United States)

Han, Jun Young; Kim, Shin Kyoung; Chung, Jin Sang; Lee, Hyun-Cheol; Lim, Jae Kuk; Lee, Jiwon; Park, Kawn Yong

2012-01-01

Objective To investigate the therapeutic effects of mechanical horseback riding for gait and balance parameters in post-stroke patients. Method This study was a non randomized prospective positive-controlled trial over a 12 week period. From May 2011 to October 2011, 37 stroke patients were recruited from our outpatient clinic and divided into two groups. The control group received the conventional physiotherapy while the intervention group received the conventional physiotherapy along with mechanical horseback riding therapy for 12 weeks. Outcome measurements of gait included the Functional Ambulation Category (FAC) and gait part of the Performance Oriented Mobility Assessment (G-POMA) while those of balance included the Berg Balance Scale (BBS) and the balance part of the Performance Oriented Mobility Assessment (B-POMA). These measurements were taken before and after treatment. Results There were no significant differences in the baseline characteristics and initial values between the two groups. When comparing baseline and 12 weeks post treatment in each group, the intervention group showed significant improvement on BBS (39.9±5.7 → 45.7±4.8, p=0.001) and B-POMA (10.4±2.6 → 12.6±2.1, p=0.001), but significant improvement on gait parameters. When comparing the groups, the dynamic balance category of BBS in post treatment showed significant difference (p=0.02). Conclusion This study suggests that mechanical horseback riding therapy may be an effective treatment tool for enhancing balance in adults with stroke. PMID:23342307

Control of maglev vehicles with aerodynamic and guideway disturbances

Science.gov (United States)

Flueckiger, Karl; Mark, Steve; Caswell, Ruth; Mccallum, Duncan

1994-01-01

A modeling, analysis, and control design methodology is presented for maglev vehicle ride quality performance improvement as measured by the Pepler Index. Ride quality enhancement is considered through active control of secondary suspension elements and active aerodynamic surfaces mounted on the train. To analyze and quantify the benefits of active control, the authors have developed a five degree-of-freedom lumped parameter model suitable for describing a large class of maglev vehicles, including both channel and box-beam guideway configurations. Elements of this modeling capability have been recently employed in studies sponsored by the U.S. Department of Transportation (DOT). A perturbation analysis about an operating point, defined by vehicle and average crosswind velocities, yields a suitable linearized state space model for multivariable control system analysis and synthesis. Neglecting passenger compartment noise, the ride quality as quantified by the Pepler Index is readily computed from the system states. A statistical analysis is performed by modeling the crosswind disturbances and guideway variations as filtered white noise, whereby the Pepler Index is established in closed form through the solution to a matrix Lyapunov equation. Data is presented which indicates the anticipated ride quality achieved through various closed-loop control arrangements.

Practical Secure Transaction for Privacy-Preserving Ride-Hailing Services

Directory of Open Access Journals (Sweden)

Chenglong Cao

2018-01-01

Full Text Available Ride-hailing service solves the issue of taking a taxi difficultly in rush hours. It is changing the way people travel and has had a rapid development in recent years. Since the service is offered over the Internet, there is a great deal of uncertainty about security and privacy. Focusing on the issue, we changed payment pattern of existing systems and designed a privacy protection ride-hailing scheme. E-cash was generated by a new partially blind signature protocol that achieves e-cash unforgeability and passenger privacy. Particularly, in the face of a service platform and a payment platform, a passenger is still anonymous. Additionally, a lightweight hash chain was constructed to keep e-cash divisible and reusable, which increases practicability of transaction systems. The analysis shows that the scheme has small communication and computation costs, and it can be effectively applied in the ride-hailing service with privacy protection.

Enhancements to NASA's Land Atmosphere Near real-time Capability for EOS (LANCE)

Science.gov (United States)

Michael, K.; Davies, D. K.; Schmaltz, J. E.; Boller, R. A.; Mauoka, E.; Ye, G.; Vermote, E.; Harrison, S.; Rinsland, P. L.; Protack, S.; Durbin, P. B.; Justice, C. O.

2016-12-01

NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) supports application users interested in monitoring a wide variety of natural and man-made phenomena. Near Real-Time (NRT) data and imagery from the AIRS, AMSR2, MISR, MLS, MODIS, OMI and VIIRS instruments are available much quicker than routine processing allows. Most data products are available within 3 hours from satellite observation. NRT imagery are generally available 3-5 hours after observation. This article describes LANCE and enhancements made to LANCE over the last year. These enhancements include: the addition of MISR L1 Georeferenced Radiance and L2 Cloud Motion Vector products, AMSR2 Unified L2B Half-Orbit 25 km EASE-Grid Surface Soil Moisture products and VIIRS VIIRS Day/Night Band, Land Surface Reflectance and Corrected Surface reflectance products. In addition, the selection of LANCE NRT imagery that can be interactively viewed through Worldview and the Global Imagery Browse Services (GIBS) has been expanded. LANCE is also working to ingest and process data from OMPS.

Optical see-through head-mounted display with occlusion capability

Science.gov (United States)

Gao, Chunyu; Lin, Yuxiang; Hua, Hong

2013-05-01

Lack of mutual occlusion capability between computer-rendered and real objects is one of fundamental problems for most existing optical see-through head-mounted displays (OST-HMD). Without the proper occlusion management, the virtual view through an OST-HMD appears "ghost-like", floating in the real world. To address this challenge, we have developed an innovative optical scheme that uniquely combines the eyepiece and see-through relay optics to achieve an occlusion-capable OST-HMD system with a very compelling form factor and high optical performances. The proposed display system was based on emerging freeform optical design technologies and was designed for highly efficient liquid crystal on silicon (LCoS) type spatial light modulator (SLM) and bright Organic LED (OLED) microdisplay. The proposed display technology was capable of working in both indoor and outdoor environments. Our current design offered a 1280x1024 color resolution based on 0.8" microdisplay and SLM. The MTF values for the majority of the fields at the cutoff frequency of 40lps/mm, which is determined by the pixel size of the microdisplay, are better than 15%. The design achieved a diagonal FOV of 40 degrees, 31.7 degrees horizontally and 25.6 degrees vertically, an exit pupil diameter of 8mm (non-vignetted), and an eye clearance of 18mm. The optics weights about 20 grams per eye. Our proposed occlusion capable OST-HMD system can easily find myriads of applications in various military and commercial sectors such as military training, gaming and entertainment.

Sustainable Passenger Transportation: Dynamic Ride-Sharing

NARCIS (Netherlands)

N.A.H. Agatz (Niels); A. Erera (Alan); M.W.P. Savelsbergh (Martin); X. Wang (Xing)

2010-01-01

textabstractRide-share systems, which aim to bring together travelers with similar itineraries and time schedules, may provide significant societal and environmental benefits by reducing the number of cars used for personal travel and improving the utilization of available seat capacity. Effective

"Paul Revere's Ride": Awakening Abolitionists

Science.gov (United States)

Lepore, Jill

2011-01-01

Henry Wadsworth Longfellow used to be both the best-known poet in the English-speaking world and the most beloved, adored by the learned and the lowly alike, read by everyone from Nathaniel Hawthorne and Abraham Lincoln to John Ruskin and Queen Victoria--and, just as avidly, by the queen's servants. "Paul Revere's Ride" is Longfellow's best-known…

Paediatric ride-on mower related injuries and plastic surgical management.

LENUS (Irish Health Repository)

Laing, T A

2011-05-01

Lawnmower related injuries cause significant morbidity in children and young teenagers. The \\'ride-on\\' mowers which are more powerful than the \\'walk behind\\' mowers are becoming increasingly popular. The incidence and severity of injuries from either type of lawnmower appears to be steadily rising as is the burden placed on local plastic surgical and emergency services in managing the care of these patients. The aims of the study were to demonstrate changing trends in lawnmower-related injuries to children presenting to a single unit over a ten-year period and to identify any association between injury severity and machine subtype (\\'ride-on\\' versus \\'walk-behind\\'). Hospital databases, theatre records and medical case notes were reviewed retrospectively of all patients under the age of 16 treated for lawnmower related injuries over a 10 year period from July 1998 to June 2008. Data gathered included patient demographics, injury site and severity, management (type and number of surgical procedures), length of hospital stay and outcome. Injury severity score was also calculated for each case. Controlling for estimated regional population changes, there was a significant increase in the number of ride-on mower related accidents in the time period 2003-2008, compared to the time period 1998-2003. Ride-on injuries had significantly higher injury severity scores, longer hospital stays and were more likely to involve amputations as compared with walk-behind injuries. Children can sustain significant injuries with unsafe lawnmower use. The current study demonstrates the increasing incidence of ride-on mower related injuries in children and identifies a greater morbidity associated with such injuries. Such presentations place intense demands on local plastic surgical services.

Establishment of Systematic Design Control/Configuration Management Processes to Enhance Engineering Capability

International Nuclear Information System (INIS)

Inagaki, T.; Hamada, T.; Ihara, T.

2016-01-01

Full text: After the accident of Fukushima Daiichi Nuclear Power Plant in 2011, Tokyo Electric Power Company (TEPCO) launched various measures to enhance plant safety and safety culture of its employees. One of the important aspects of these measures is to enhance engineering capability and TEPCO is conducting actions to establish systematic design control and configuration management processes as an important foundation of such engineering capability. This paper describes how TEPCO is establishing systematic configuration management processes from three aspects, i.e., design requirement and bases management, facility configuration control, and configuration change management. It also provides brief information of the IT systems that are being introduced and will support the systematic design control and configuration management processes. (author

Hardness of Preemptive Finite Capacity Dial-a-Ride

DEFF Research Database (Denmark)

Gørtz, Inge Li

2006-01-01

In the Finite Capacity Dial-a-Ride problem the input is a metric space, a set of objects, each specifying a source and a destination, and an integer k---the capacity of the vehicle used for making the deliveries. The goal is to compute a shortest tour for the vehicle in which all objects can...... and Raghavachari [FOCS '98] gave a min{O(log N),O(k)}-approximation algorithm for the preemptive version of the problem. In this paper we show that the preemptive Finite Capacity Dial-a-Ride problem has no $min{O(log^{1/4-\\epsilon}N),k^{1-\\epsilon}}$-approximation algorithm for any $\\epsilon>0$ unless all problems...

Ride Control Systems - Reduced Motions on the Cost of Increased Sectional Forces ?

DEFF Research Database (Denmark)

Folsø, R.; Nielsen, Ulrik Dam; Torti, F.

2003-01-01

Implementation of passive and active ride control systems into both linear frequency and non-linear time domain strip theories is described. The ride control systems considered can consist of T-foils, fins or a combination of these. These appendages are taken into account by considering the lift...

Improving Coastal Ocean Color Validation Capabilities through Application of Inherent Optical Properties (IOPs)

Science.gov (United States)

Mannino, Antonio

2008-01-01

Understanding how the different components of seawater alter the path of incident sunlight through scattering and absorption is essential to using remotely sensed ocean color observations effectively. This is particularly apropos in coastal waters where the different optically significant components (phytoplankton, detrital material, inorganic minerals, etc.) vary widely in concentration, often independently from one another. Inherent Optical Properties (IOPs) form the link between these biogeochemical constituents and the Apparent Optical Properties (AOPs). understanding this interrelationship is at the heart of successfully carrying out inversions of satellite-measured radiance to biogeochemical properties. While sufficient covariation of seawater constituents in case I waters typically allows empirical algorithms connecting AOPs and biogeochemical parameters to behave well, these empirical algorithms normally do not hold for case I1 regimes (Carder et al. 2003). Validation in the context of ocean color remote sensing refers to in-situ measurements used to verify or characterize algorithm products or any assumption used as input to an algorithm. In this project, validation capabilities are considered those measurement capabilities, techniques, methods, models, etc. that allow effective validation. Enhancing current validation capabilities by incorporating state-of-the-art IOP measurements and optical models is the purpose of this work. Involved in this pursuit is improving core IOP measurement capabilities (spectral, angular, spatio-temporal resolutions), improving our understanding of the behavior of analytical AOP-IOP approximations in complex coastal waters, and improving the spatial and temporal resolution of biogeochemical data for validation by applying biogeochemical-IOP inversion models so that these parameters can be computed from real-time IOP sensors with high sampling rates. Research cruises supported by this project provides for collection and

Enhanced science capability on the International Space Station

Science.gov (United States)

Felice, Ronald R.; Kienlen, Mike

2002-12-01

It is inevitable that the International Space Station (ISS) will play a significant role in the conduct of science in space. However, in order to provide this service to a wide and broad community and to perform it cost effectively, alternative concepts must be considered to complement NASA"s Institutional capability. Currently science payload forward and return data services must compete for higher priority ISS infrastructure support requirements. Furthermore, initial astronaut crews will be limited to a single shift. Much of their time and activities will be required to meet their physical needs (exercise, recreation, etc.), station maintenance, and station operations, leaving precious little time to actively conduct science payload operations. ISS construction plans include the provisioning of several truss mounted, space-hardened pallets, both zenith and nadir facing. The ISS pallets will provide a platform to conduct both earth and space sciences. Additionally, the same pallets can be used for life and material sciences, as astronauts could place and retrieve sealed canisters for long-term micro-gravity exposure. Thus the pallets provide great potential for enhancing ISS science return. This significant addition to ISS payload capacity has the potential to exacerbate priorities and service contention factors within the exiting institution. In order to have it all, i.e., more science and less contention, the pallets must be data smart and operate autonomously so that NASA institutional services are not additionally taxed. Specifically, the "Enhanced Science Capability on the International Space Station" concept involves placing data handling and spread spectrum X-band communications capabilities directly on ISS pallets. Spread spectrum techniques are considered as a means of discriminating between different pallets as well as to eliminate RFI. The data and RF systems, similar to that of "free flyers", include a fully functional command and data handling system

California Amusement Rides and Liability

Science.gov (United States)

Epstein, Adam

2005-01-01

Twenty-three-year-old Cristina Moreno traveled from Spain to California for her honeymoon in 2000. As part of her visit, she rode the Indiana Jones amusement ride at Disneyland with her new husband. On June 25, 2000, she suffered a brain injury, and she eventually died on September 1, 2000, as a result of injuries allegedly sustained while riding…

Therapeutic Effects of Horseback Riding Interventions: A Systematic Review and Meta-analysis.

Science.gov (United States)

Stergiou, Alexandra; Tzoufi, Meropi; Ntzani, Evangelia; Varvarousis, Dimitrios; Beris, Alexandros; Ploumis, Avraam

2017-10-01

Equine-assisted therapies, such as therapeutic riding and hippotherapy, are believed to have positive physical and emotional effects in individuals with neuromotor, developmental, and physical disabilities. The purpose of this review was to determine whether therapeutic riding and hippotherapy improve balance, motor function, gait, muscle symmetry, pelvic movement, psychosocial parameters, and the patients' overall quality of life. In this study, a literature search was conducted on MEDLINE, CINAHL, MBASE, SportDiscus, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, PEDro, DARE, Google Scholar, and Dissertation Abstracts. Only studies with a control/comparison group or self-controlled studies performing preintervention and postintervention assessment were included. Excluded were (1) studies not providing data on baseline score or end-point outcome, (2) single-subject studies, (3) studies providing only qualitative data, and (4) studies that used a mechanical horse. Sixteen trials were included. The methodologic quality of each study was evaluated using Downs and Black quality assessment tool. Most of the studies showed a trend toward a beneficial effect of therapeutic riding and hippotherapy on balance and gross motor function. The meta-analysis showed improvement in both the Berg Balance Scale and the Gross Motor Function Measure in therapeutic riding and hippotherapy programs. Programs such as therapeutic riding and hippotherapy are a viable intervention option for patients with balance, gait, and psychomotor disorders.

Severe Sunburn After a Hot Air Balloon Ride: A Case Report and Literature Review.

Science.gov (United States)

Ozturk, Sinan; Karagoz, Huseyin

2015-01-01

Hot air balloon tours are very popular among travelers worldwide. Preventable burn injuries associated with hot air balloon rides have been reported during crashes into power lines, in propane burner explosions, and following contact with the propane burner tanks. We present a case of severe repeated sunburn, which poses another risk of preventable injury during hot air balloon rides, and briefly discuss the injury epidemiology of hot air balloon rides. © 2015 International Society of Travel Medicine.

Effects of alcohol on motorcycle riding skills

Science.gov (United States)

2007-12-01

Alcohol is known to disrupt the effect of neurotransmitters and impair various psychomotor skills. Indeed, alcohol intoxication is a significant risk factor for fatal traffic crashes, especially when riding a motorcycle. At present, there is sparse r...

Stay Safe Riding Bikes or Skating Outside

Centers for Disease Control (CDC) Podcasts

2011-02-02

In this podcast for kids, the Kidtastics talk about safety when outside, riding bikes or skating.  Created: 2/2/2011 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 2/2/2011.

Pricing Decision under Dual-Channel Structure considering Fairness and Free-Riding Behavior

Directory of Open Access Journals (Sweden)

Yongmei Liu

2014-01-01

Full Text Available Under dual-channel structure, the free-riding behavior based on different service levels between online channel and offline channel cannot be avoided, which would lead to channel unfairness. This study implies that the dual-channel supply chain is built up by online channel controlled by manufacturer and traditional channel controlled by retailer, respectively. Under this channel structure, we rebuild the linear demand function considering free-riding behavior and modify the pricing model based on channel fairness. Then the influences of fair factor and free-riding behavior on manufacturer and retailer pricing and performance are discussed. Finally, we propose some numerical analysis to provide some valuable recommendations for manufacturer and retailer improving channel management performance.

Toward Vision Oriented Organization through Foresight Capability Development

Directory of Open Access Journals (Sweden)

Gianita BLEOJU

2014-11-01

Full Text Available Dealing with complexity is becoming increasingly difficult for organizations, due to limited replicable abilities, once management performance was remunerated by successful decisions on the marketplace. The competitive advantage, based upon current documented organizational management expertise, deployed into patterns of competitive behavior, prove to be unsustainable. Therefore, we assist to a relative emergency of strategic intelligence adjustment framework, to channel the managerial capability mechanisms, from current detective orientation capabilities toward anticipatory ones. Based upon exploitation of an organizational profiling database, we try our contribution to this challenging debate, by formulating recommendations for strategic adjustment and prototype testing of the potential solutions, through a designed transition matrix from market oriented to vision oriented organizations.

Topology Optimization of Vehicle Body Structure for Improved Ride & Handling

OpenAIRE

Lövgren, Sebastian; Norberg, Emil

2011-01-01

Ride and handling are important areas for safety and improved vehicle control during driving. To meet the demands on ride and handling a number of measures can be taken. This master thesis work has focused on the early design phase. At the early phases of design, the level of details is low and the design freedom is big. By introducing a tool to support the early vehicle body design, the potential of finding more efficient structures increases. In this study, topology optimization of a vehicl...

Hacking Your Ride: Is Web 2.0 Creating Vulnerabilities To Surface Transportation

Science.gov (United States)

2016-09-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release. Distribution is unlimited. HACKING YOUR RIDE...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE HACKING YOUR RIDE: IS WEB 2.0 CREATING VULNERABILITIES TO SURFACE...Prescribed by ANSI Std. 239-18 ii THIS PAGE INTENTIONALLY LEFT BLANK iii Approved for public release. Distribution is unlimited. HACKING

Calling, texting, and searching for information while riding a motorcycle: A study of university students in Vietnam.

Science.gov (United States)

Truong, Long T; De Gruyter, Chris; Nguyen, Hang T T

2017-08-18

The objective of this study was to investigate the prevalence of calling, texting, and searching for information while riding a motorcycle among university students and the influences of sociodemographic characteristics, social norms, and risk perceptions on these behaviors. Students at 2 university campuses in Hanoi and Ho Chi Minh City, the 2 largest cities in Vietnam, were invited to participate in an anonymous online survey. Data collection was conducted during March and May 2016. There were 741 respondents, of whom nearly 90% of students (665) were motorcycle riders. Overall prevalence of mobile phone use while riding is 80.9% (95% confidence interval [CI], 77.9-83.9%) with calling having a higher level of prevalence than texting or searching for information while riding: 74% (95% CI, 70.7-77.3%) vs. 51.7% (95% CI, 47.9-55.5%) and 49.9% (95% CI, 46.1-53.7%), respectively. Random parameter ordered probit modeling results indicate that mobile phone use while riding is associated with gender, motorcycle license duration, perceived crash risk, perceived risk of mobile phone snatching, and perceptions of friends' mobile phone use while riding. Mobile phone use while riding a motorcycle is highly prevalent among university students. Educational programs should focus on the crash and economic risk of all types of mobile phone use while riding, including calling, texting, and searching for information. In addition, they should consider targeting the influence of social norms and peers on mobile phone use while riding.

The Value of Optimization in Dynamic Ride-Sharing: a Simulation Study in Metro Atlanta

NARCIS (Netherlands)

N.A.H. Agatz (Niels); A. Erera (Alan); M.W.P. Savelsbergh (Martin); X. Wang (Xing)

2010-01-01

textabstractSmartphone technology enables dynamic ride-sharing systems that bring together people with similar itineraries and time schedules to share rides on short-notice. This paper considers the problem of matching drivers and riders in this dynamic setting. We develop optimization-based

Riding Quality Model for Asphalt Pavement Monitoring Using Phase Array Type L-band Synthetic Aperture Radar (PALSAR

Directory of Open Access Journals (Sweden)

Kamiya Yoshikazu

2010-11-01

Full Text Available There are difficulties associated with near-real time or frequent pavement monitoring, because it is time consuming and costly. This study aimed to develop a binary logit model for the evaluation of highway riding quality, which could be used to monitor pavement conditions. The model was applied to investigate the influence of backscattering values of Phase Array type L-band Synthetic Aperture Radar (PALSAR. Training data obtained during 3–7 May 2007 was used in the development process, together with actual international roughness index (IRI values collected along a highway in Ayutthaya province, Thailand. The analysis showed that an increase in the backscattering value in the HH or the VV polarization indicated the poor condition of the pavement surface and, of the two, the HH polarization is more suitable for developing riding quality evaluation. The model developed was applied to analyze highway number 3467, to demonstrate its capability. It was found that the assessment accuracy of the prediction of the highway level of service was 97.00%. This is a preliminary study of the proposed technique and more intensive investigation must be carried out using ALOS/PALSAR images in various seasons.

Spinal Cord Injuries in Wave-Riding Sports: The Influence of Environmental and Sport-Specific Factors.

Science.gov (United States)

Falconi, Audrey; Flick, David; Ferguson, Jason; Glorioso, John E

2016-01-01

Spinal cord injury is a nonfatal, catastrophic consequence of wave-riding sports. With surfing at the core, a multitude of activities have evolved that attempt to harness the power of ocean waves. The unique qualities of each wave-riding sport, in combination with the environmental factors of the ocean, define the risk for potential injuries. As wave-riding sports have become more advanced, athletes continue to push physical barriers. Taller waves are attempted while incorporating aerial maneuvers, all without protective equipment.

Free Riding Indexes for Ukrainian Economics Teachers.

Science.gov (United States)

McCorkle, Sarapage; Watts, Michael

1996-01-01

Reports on the adaptation and replication of Jane Leuthold's experiment concerning consumer choice, investments, and free riding indexes. A similar experiment, conducted in a Ukrainian classroom, produced similar results with a few notable exceptions. The exceptions reflected the Ukrainians' lack of familiarity with western economic thought. (MJP)

Calming the Waters or Riding the Waves?

DEFF Research Database (Denmark)

Rydén, Pernille; Kottika, Efthymia; Hossain, Muhammad Ismail

Traditional consumer anger management tends to be compromising rather than empowering the brand. This paper conceptualizes and provides a case example on how consumer empowerment and negative emotions can in fact create opportunities for companies to ride the waves of consumer anger in a way that...

Modified Ride-On Cars and Young Children with Disabilities: Effects of Combining Mobility and Social Training

Directory of Open Access Journals (Sweden)

Hsiang-Han Huang

2018-01-01

Full Text Available BackgroundResearch has shown that the use of power mobility devices is safe and beneficial for motor and cognitive development in children with motor disabilities; nevertheless, strong evidence of the benefits for social skill development is limited. This study aimed to examine the effects of combining ride-on car training with an adult-directed, social interaction program in a hospital-based environment on mobility and social functions in young children with motor disabilities.MethodsThis study used a prospective, nonequivalent pretest–posttest control group design. Twenty-nine young children with motor disabilities, aged between 1 and 3 years, were recruited from local hospitals in Taiwan. The treatment group (n = 15 underwent 2-h ride-on car training sessions twice per week for a total of 9 weeks in the hospital environment. The control group (n = 14 underwent a 9-week home education program (mean: 200 min/week focusing on mobility and social skills training. The Chinese version of the Pediatric Evaluation of Disability Inventory, Parenting Stress Index, and Goal Attainment Scaling were administered to all participants before and after the intervention, and at the end of the 9-week follow-up phase.ResultsMobility and social functions significantly improved in both groups after the 9-week intervention, but this improvement was not maintained at the follow-up phase. The treatment group showed significantly better improvement in social function, parenting stress levels, and goal achievement than the control group at posttest.ConclusionThis two-group design study showed the benefits of combining a ride-on car use with a family-centered, structured, social interaction program for positive impacts on mobility, social function, and parenting stress levels. The combination of a modified ride-on car and a social training program has the potential to enhance socialization in young children with motor disabilities.Clinical Trial

CircleRides: developing an older adult transportation application and evaluating feedback.

Science.gov (United States)

Heinz, Melinda; Kelly, Norene

2015-05-01

The purpose of the current study was to assess perceptions of CircleRides, a paper prototype of a service website designed to meet older adult transportation needs. Researchers used purposive sampling to conduct two focus groups comprised of older adults to obtain feedback on the CircleRides prototype at the beginning of its iterative design process. One focus group was conducted in a continuing care retirement community (n = 13) and the other in an independent living community for older adults (n = 11). The study assessed perceptions of the CircleRides prototype as well as self-reported older adult transportation preferences and needs. Three themes emerged from the data: (a) trust and concern, (b) socialization, and (c) flexibility and options. Researchers found that participants are interested in transportation options; however, concern exists about trusting a new system or prototype that has not established a reputation. Findings from the current study offer lessons learned for future iterations and for creating transportation prototypes for older adults. Copyright 2015, SLACK Incorporated.

Studies on High Voltage Ride through Technologies in Wind Turbines%风力发电机组高电压穿越技术研究

Institute of Scientific and Technical Information of China (English)

马伟娜; 姚万业; 白恺

2014-01-01

为保障风电大规模接入条件下电力系统的高效稳定运行，电网电压骤升对风力发电机组的影响分析及相应高电压穿越技术的研究逐步成为国内外研究热点。通过分析风力发电机组大规模脱网事件对高电压穿越概念进行理解，结合现行国内外高电压穿越标准及电压骤升下风机的暂态过程，介绍了实现电压穿越的不同技术方案，为风力发电机组高电压穿越技术的研究和应用提供参考。%For the efficient and stable operation of the power system integrated with large scale of wind power,the response of the wind turbine generation system to the voltage swells of the power grid and technical principles of HVRT have gradually become a focus of studies at home and abroad. This paper introduces and interprets the high voltage ride-through(HVRT) concept by analyzing the large-scaled off-grid event, and presents different technical principles based on the current domestic and foreign HVRT standards and the transient process of the wind turbine under the voltage swell. The paper can provide useful reference for the research and application of the high voltage ride through technology for the wind turbine.

Fault ride-through capability of wind turbine connected to the grid in case of unbalanced voltages

Directory of Open Access Journals (Sweden)

Ivanović Zoran R.

2016-01-01

Full Text Available This paper deals with control of wind turbine connected to the grid through the back-to-back converter in case of unbalanced grid voltages. The motivation for this research has been found in recent transmission and distribution grid code, which demand modern wind turbines to stay connected to the grid and supply the highest possible apparent power during the grid disturbances. In order to comply with these requirements we proposed improved dual vector current controller to deal with the unbalance imposed by the electrical grid. Controller provides injection of active and reactive power to the grid, even if the voltages are lower than the nominal one. The results are validated using low power prototype and contemporary hardware-in-the-loop emulation platform. In both cases the controller is based on TMS320F2812 DSP. [Projekat Ministarstva nauke Republike Srbije, br. III 042004 and by the Provincial Secretariat for Science and Technological Development of AP Vojvodina under contract No. 114-451-3508/2013-04

Port Authority of Allegheny County Park and Rides

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset includes the GIS shapefile for Port Authority of Allegheny County's Park and Ride facilities. This layer is updated annually or on an as-needed basis...

Research on the Effects of Hydropneumatic Parameters on Tracked Vehicle Ride Safety Based on Cosimulation

Directory of Open Access Journals (Sweden)

Shousong Han

2017-01-01

Full Text Available Ride safety of a tracked vehicle is the key focus of this research. The factors that affect the ride safety of a vehicle are analyzed and evaluation parameters with their criteria are proposed. A multibody cosimulation approach is used to investigate the effects of hydropneumatic parameters on the ride safety and aid with design optimization and tuning of the suspension system. Based on the cosimulation environment, the vehicle multibody dynamics (MBD model and the road model are developed using RecurDyn, which is linked to the hydropneumatic suspension model developed in Lab AMESim. Test verification of a single suspension unit is accomplished and the suspension parameters are implemented within the hydropneumatic model. Virtual tests on a G class road at different speeds are conducted. Effects of the accumulator charge pressure, damping diameter, and the track tensioning pressure on the ride safety are analyzed and quantified. This research shows that low accumulator charge pressure, improper damping diameter, and insufficient track tensioning pressure will deteriorate the ride safety. The results provide useful references for the optimal design and control of the parameters of a hydropneumatic suspension.

Development of an ultra-portable ride quality meter.

Science.gov (United States)

2012-12-01

FRAs Office of Research and Development has funded the development of an ultra-portable ride quality meter (UPRQM) under the Small Business and Innovative Research (SBIR) program. Track inspectors can use the UPRQM to locate segments of track that...

CORONA ACADEMY, Opportunities for Enhancement of Training Capabilities in VVER Technology

International Nuclear Information System (INIS)

Ilieva, M.; Dieguez Porras, P.; Klepakova, A.

2016-01-01

Full text: The general objective of the project CORONA II is to enhance the safety of nuclear installations through further improvement of the training capabilities for providing the necessary personnel competencies in VVER area. More specific objective of the project is to continue the development of a state-of-the-art regional training network for VVER competence called CORONA Academia. The project aims at continuation of the European cooperation and support in this area for preservation and further development of expertise in the nuclear field by improvement of higher education and training. The consortium is focusing its effort on using the most advanced ways of providing training to the trainees, saving cost and time–distance learning and e-learning approaches which will be tested in CORONA II Project. The knowledge management portal will integrate the information on VVER web into a single communication system and develop and implement a semantic web structure to achieve mutual recognition of authentication information with other databases. That will enable the partners to share the materials available in each specific training center. (author

Advancing Capabilities for Understanding the Earth System Through Intelligent Systems, the NSF Perspective

Science.gov (United States)

Gil, Y.; Zanzerkia, E. E.; Munoz-Avila, H.

2015-12-01

The National Science Foundation (NSF) Directorate for Geosciences (GEO) and Directorate for Computer and Information Science (CISE) acknowledge the significant scientific challenges required to understand the fundamental processes of the Earth system, within the atmospheric and geospace, Earth, ocean and polar sciences, and across those boundaries. A broad view of the opportunities and directions for GEO are described in the report "Dynamic Earth: GEO imperative and Frontiers 2015-2020." Many of the aspects of geosciences research, highlighted both in this document and other community grand challenges, pose novel problems for researchers in intelligent systems. Geosciences research will require solutions for data-intensive science, advanced computational capabilities, and transformative concepts for visualizing, using, analyzing and understanding geo phenomena and data. Opportunities for the scientific community to engage in addressing these challenges are available and being developed through NSF's portfolio of investments and activities. The NSF-wide initiative, Cyberinfrastructure Framework for 21st Century Science and Engineering (CIF21), looks to accelerate research and education through new capabilities in data, computation, software and other aspects of cyberinfrastructure. EarthCube, a joint program between GEO and the Advanced Cyberinfrastructure Division, aims to create a well-connected and facile environment to share data and knowledge in an open, transparent, and inclusive manner, thus accelerating our ability to understand and predict the Earth system. EarthCube's mission opens an opportunity for collaborative research on novel information systems enhancing and supporting geosciences research efforts. NSF encourages true, collaborative partnerships between scientists in computer sciences and the geosciences to meet these challenges.

Leisure riding horses: research topics versus the needs of stakeholders.

Science.gov (United States)

Janczarek, Iwona; Wilk, Izabela

2017-07-01

Horses intended for leisure riding do not undergo any selection and most often retired sports horses or defective horses are chosen, as a low selling price determines their purchase by a leisure riding center. Unfortunately, horses bought at low prices usually have low utility value, are difficult to handle, require a special or individual approach and do not provide satisfaction in riding. However, neither modern horse breeding nor scientific research address the need to breed horses for leisure activities. There is no clear definition of a model leisure horse and criteria or information for its selection are not readily available in scientific publications. A wide spectrum of research methods may be used to evaluate various performance traits in horses intended for leisure activities. The fact that the population of recreational horses and their riders outnumber sporting horses should attract the special attention of scientific research. Their utility traits need to be determined with modern technology and methods in the same way they are for sporting horses. Such a system of evaluation would be very helpful for riders. © 2017 Japanese Society of Animal Science.

Validation of a Functional Pyelocalyceal Renal Model for the Evaluation of Renal Calculi Passage While Riding a Roller Coaster.

Science.gov (United States)

Mitchell, Marc A; Wartinger, David D

2016-10-01

The identification and evaluation of activities capable of dislodging calyceal renal calculi require a patient surrogate or validated functional pyelocalyceal renal model. To evaluate roller coaster facilitation of calyceal renal calculi passage using a functional pyelocalyceal renal model. A previously described adult ureteroscopy and renoscopy simulator (Ideal Anatomic) was modified and remolded to function as a patient surrogate. Three renal calculi of different sizes from the patient who provided the original computed tomographic urograph on which the simulator was based were used. The renal calculi were suspended in urine in the model and taken for 20 rides on the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando, Florida. The roller coaster rides were analyzed using variables of renal calculi volume, calyceal location, model position on the roller coaster, and renal calculi passage. Sixty renal calculi rides were analyzed. Independent of renal calculi volume and calyceal location, front seating on the roller coaster resulted in a passage rate of 4 of 24. Independent of renal calculi volume and calyceal location, rear seating on the roller coaster resulted in a passage rate of 23 of 36. Independent of renal calculi volume in rear seating, calyceal location differed in passage rates, with an upper calyceal calculi passage rate of 100%; a middle calyceal passage rate of 55.6%; and a lower calyceal passage rate of 40.0%. The functional pyelocalyceal renal model serves as a functional patient surrogate to evaluate activities that facilitate calyceal renal calculi passage. The rear seating position on the roller coaster led to the most renal calculi passages.

A Motion Simulator Ride Associated With Headache and Subdural Hematoma: First Case Report.

Science.gov (United States)

Scranton, Robert A; Evans, Randolph W; Baskin, David S

2016-02-01

We report the first case report of symptomatic bilateral subdural hematomas (SDH) associated with riding a centrifugal motion simulator ride. A previously healthy 55-year-old male developed new onset daily headaches 1 week after going on the ride that were due to symptomatic bilateral SDH requiring operative intervention with a full recovery. There was no history of other trauma or other systemic or intracranial abnormality to account for the development of the SDH. We review the headaches and other clinical features associated with chronic SDH. Twelve cases of roller coaster headaches due to SDH associated with riding roller coasters have been reported. The pathophysiology is reviewed, which we believe is the same mechanism that may be responsible in this case. Although it is possible that this neurovascular injury is truly rare, it is also possible that this injury is underreported as patients and physicians may not make the association or physicians have not reported additional cases. The risk of this injury likely increases with age, as the size of the subdural space increases, and may support the maxim that "roller coasters and simulators are for kids." © 2015 American Headache Society.

Minimum Makespan Multi-vehicle Dial-a-Ride

DEFF Research Database (Denmark)

Gørtz, Inge Li; Nagarajan, Viswanath; Ravi, R.

2009-01-01

be left at intermediate vertices and transported by more than one vehicle, while being moved from source to destination. Approximation algorithms for the single vehicle Dial-a-Ride problem (q = 1) have been considered in [3,10]. Our main results are an O(log3n)-approximation algorithm for preemptive multi...

Radiative inflation and dark energy RIDEs again after BICEP2

International Nuclear Information System (INIS)

Bari, Pasquale Di; King, Stephen F.; Merle, Alexander; Luhn, Christoph; Schmidt-May, Angnis

2014-01-01

Following the ground-breaking measurement of the tensor-to-scalar ratio r=0.20 +0.07 -0.05 by the BICEP2 collaboration, we perform a statistical analysis of a model that combines Radiative Inflation with Dark Energy (RIDE) based on the M 2 |Φ| 2 ln(|Φ| 2 /Λ 2 ) potential and compare its predictions to those based on the traditional chaotic inflation M 2 |Φ| 2 potential. We find a best-fit value in the RIDE model of r=0.18 as compared to r=0.17 in the chaotic model, with the spectral index being n S =0.96 in both models

An application of zeta potential method for the selection of nano-fluids to enhance IVR capability

International Nuclear Information System (INIS)

Pham Quynh Trang; Kim, Tae Il; Chang, Soon Heung

2009-01-01

In-vessel Retention (IVR) is one of the key severe accident management strategies that have been applied currently for advanced light water reactors such as APR1000 or APR1400. The concept of IVR consists of external cooling of the reactor vessel by flooding the reactor cavity to remove the decay heat from the molten core through the lower head of the vessel. However, the heat removal process is limited by the occurrence of critical heat flux (CHF) at the reactor vessel outer surface that may lead to a sharp increase of local temperature, damaging the integrity of the reactor vessel. In order to obtain higher power of nuclear reactors and to assure the achievement of the IVR capability during accident conditions, an enhancement of CHF at the outer surface of the vessel is required. The potential use of nano-fluids to increase the CHF is among the main IVR enhancing approaches. In this study, Al 2 O 3 and CNT nano-fluids with different concentrations have been used as the potential coolant to enhance IVR capabilities. The dispersion stability of the nano-fluids was verified by zeta potential measurements. The results showed effects of time, concentration and pH on the stability of nanofluids. Three types of nano-fluids were selected as the candidates to apply for the IVR. A series of experiments have been performed in this study to understand the pool-boiling critical heat flux behavior on downward facing surfaces submerged in a pool of nano-fluids at very low concentration. The inclination angle was changed from horizontal to vertical to investigate the effect of orientation on CHF enhancement which is needed for the application in IVR

Demographic and psychological variables affecting test subject evaluations of ride quality

Science.gov (United States)

Duncan, N. C.; Conley, H. W.

1975-01-01

Ride-quality experiments similar in objectives, design, and procedure were conducted, one using the U.S. Air Force Total In-Flight Simulator and the other using the Langley Passenger Ride Quality Apparatus to provide the motion environments. Large samples (80 or more per experiment) of test subjects were recruited from the Tidewater Virginia area and asked to rate the comfort (on a 7-point scale) of random aircraft motion typical of that encountered during STOL flights. Test subject characteristics of age, sex, and previous flying history (number of previous airplane flights) were studied in a two by three by three factorial design. Correlations were computed between one dependent measure, the subject's mean comfort rating, and various demographic characteristics, attitudinal variables, and the scores on Spielberger's State-Trait Anxiety Inventory. An effect of sex was found in one of the studies. Males made higher (more uncomfortable) ratings of the ride than females. Age and number of previous flights were not significantly related to comfort ratings. No significant interactions between the variables of age, sex, or previous number of flights were observed.

Data Compatibility to Enhance Sustainable Capabilities for Autonomous Analytics in IoT

Directory of Open Access Journals (Sweden)

Kaleem Razzaq Malik

2017-05-01

Full Text Available The collection of raw data is based on sensors embedded in devices or the environment for real-time data extraction. Nowadays, the Internet of Things (IoT environment is used to support autonomous data collection by reducing human involvement. It is hard to analyze such data, especially when working with the sensors in a real-time environment. On using data analytics in IoT with the help of RDF, many issues can be resolved. Resultant data will have a better chance of quality analytics by reforming data into the semantical annotation. Industrial correspondence through data will be improved by the induction of semantics at large due to efficient data capturing, whereas one popular medium of sensors’ data storage is Relational Database (RDB. This study provides a complete automated mechanism to transform from loosely structured data stored in RDB into RDF. These data are obtained from sensors in semantically annotated RDF stores. The given study comprises methodology for improving compatibility by introducing bidirectional transformation between classical DB and RDF data stores to enhance the sustainable capabilities of IoT systems for autonomous analytics. Two case studies, one on weather and another on heart-rate measurement collections through IoT sensors, are used to show the transformation process in operation.

Power quality improvement of single-phase photovoltaic systems through a robust synchronization method

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng

2014-01-01

An increasing amount of single-phase photovoltaic (PV) systems on the distribution network requires more advanced synchronization methods in order to meet the grid codes with respect to power quality and fault ride through capability. The response of the synchronization technique selected...... is crucial for the performance of PV inverters. In this paper, a new synchronization method with good dynamics and accurate response under highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which cancels out the oscillations on the synchronization signals due...

Effect of health education on the riding habits of commercial motorcyclists in Uyo, southern Nigeria.

Science.gov (United States)

Johnson, O E; Owoaje, E T

2012-01-01

The increasing number of motorcyclists in Nigeria has led to a rise in poor road safety practices leading to increased rate of accidents. This study was conducted to implement and evaluate the effect of safety education on riding habits of motorcyclists in Uyo, Nigeria. The intervention study was conducted among commercial motorcyclists in Uyo with controls from another town in Akwa Ibom State. Baseline information was collected from both groups on their riding habits. Motorcyclists in Uyo were educated on appropriate road safety practices. Data was collected from both groups three months later and analysed using the Statistical Package for Social Sciences version 11. A total of 200 respondents participated in the study, 100 per group. At 3 months post-intervention, those riding when tired reduced in the intervention group from 69% at baseline to 42% (p Safety education improved many riding habits of motorcyclists in the intervention group. Road safety education is recommended for all motorcyclists to ensure safer road use.

Understanding dynamic capabilities through knowledge management

DEFF Research Database (Denmark)

Nielsen, Anders Paarup

2006-01-01

In the paper eight knowledge management activities are identified; knowledge creation, acquisition, capture, assembly, sharing, integration, leverage and exploitation. These activities are assembled into the three dynamic capabilities of knowledge development, knowledge (re......)combination and knowledge use. The dynamic capabilities and the associated knowledge management activities create flows to and from the firm’s stock of knowledge and they support the creation and use of organizational capabilities....

Enhancing the Radio Astronomy Capabilities at NASA's Deep Space Network

Science.gov (United States)

Lazio, Joseph; Teitelbaum, Lawrence; Franco, Manuel M.; Garcia-Miro, Cristina; Horiuchi, Shinji; Jacobs, Christopher; Kuiper, Thomas; Majid, Walid

2015-08-01

NASA's Deep Space Network (DSN) is well known for its role in commanding and communicating with spacecraft across the solar system that produce a steady stream of new discoveries in Astrophysics, Heliophysics, and Planetary Science. Equipped with a number of large antennas distributed across the world, the DSN also has a history of contributing to a number of leading radio astronomical projects. This paper summarizes a number of enhancements that are being implemented currently and that are aimed at increasing its capabilities to engage in a wide range of science observations. These enhancements include* A dual-beam system operating between 18 and 27 GHz (~ 1 cm) capable of conducting a variety of molecular line observations, searches for pulsars in the Galactic center, and continuum flux density (photometry) of objects such as nearby protoplanetary disks* Enhanced spectroscopy and pulsar processing backends for use at 1.4--1.9 GHz (20 cm), 18--27 GHz (1 cm), and 38--50 GHz (0.7 cm)* The DSN Transient Observatory (DTN), an automated, non-invasive backend for transient searching* Larger bandwidths (>= 0.5 GHz) for pulsar searching and timing; and* Improved data rates (2048 Mbps) and better instrumental response for very long baseline interferometric (VLBI) observations with the new DSN VLBI processor (DVP), which is providing unprecedented sensitivity for maintenance of the International Celestial Reference Frame (ICRF) and development of future versions.One of the results of these improvements is that the 70~m Deep Space Station 43 (DSS-43, Tidbinbilla antenna) is now the most sensitive radio antenna in the southern hemisphere. Proposals to use these systems are accepted from the international community.Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics & Space Administration.

Overuse Injuries Associated with Mountain Biking: Is Single-Speed Riding a Predisposing Factor?

Directory of Open Access Journals (Sweden)

Michael T. Lebec

2014-01-01

Full Text Available Though mountain bikers are at significant risk for overuse injury, there is minimal quality research describing this relationship. Single-speed mountain biking, in which participants pedal a bike with only a single gear, may place riders at even greater risk for overuse problems due to the disproportionate physical effort associated with this type of riding. The focus of this study was to provide additional perspective on overuse injuries sustained by mountain bikers and to determine if single-speed mountain biking places participants at greater risk for overuse conditions. Four hundred and four (404 mountain bikers were surveyed concerning overuse injuries sustained during the previous year. Findings indicate that 63% of respondents reported an overuse injury affecting at least one area with the most commonly reported areas being the lumbar spine, knees, hand/wrist, and cervical spine. Individuals riding single-speed mountain bikes did not have a higher incidence of overuse injuries than riders of multiple-geared bikes. However, respondents who split time between riding single-speed and multiple-geared bikes were significantly more likely to report an overuse syndrome than those only riding single-speed or multiple-geared bikes (p = 0.0104. This group of riders may be at greater risk for overuse injury due to excessive fatigue and poor biomechanics.

Influência das efemérides transmitidas e precisas no transporte de coordenadas

Directory of Open Access Journals (Sweden)

Felipe Mendes Suci

2010-01-01

Full Text Available O presente estudo descreve uma metodologia que dá suporte para a comparação dos resultados obtidos de processamentos com dados GPS utilizando-se de diferentes tipos de efemérides (transmitidas, ultrarrápidas, rápidas e finais. A metodologia proposta consta de diferentes etapas, que vão desde a obtenção dos dados RINEX (GPS e .sp3 (efemérides precisas nos sítios do IBGE e IGS respectivamente, passando pela atualização e transformação entre diferentes referenciais geodésicos (utilizando a Transformação Generalizada de Helmert, mudança entre sistemas cartesiano geocêntrico e geodésico local até a comparação das discrepâncias obtidas entre as coordenadas obtidas a partir do processamento (utilizando-se do aplicativo Trimble Geomatics Office - TGO e as coordenadas presentes nos descritivos. Os resultados mostraram que não há diferença relevante entre as soluções alcançadas com os diferentes tipos de efemérides precisas para as linhas de base analisadas nesse trabalho, porém, houve diferença considerável entre essas coordenadas e as obtidas com as efemérides transmitidas.

Facile template-directed synthesis of carbon-coated SnO2 nanotubes with enhanced Li-storage capabilities

International Nuclear Information System (INIS)

Zhu, Xiaoshu; Zhu, Jingyi; Yao, Yinan; Zhou, Yiming; Tang, Yawen; Wu, Ping

2015-01-01

Herein, a novel type of carbon-coated SnO 2 nanotubes has been designed and synthesized through a facile two-step hydrothermal approach by using ZnO nanorods as templates. During the synthetic route, SnO 2 nanocrystals and carbon layer have been uniformly deposited on the rod-like templates in sequence, meanwhile ZnO nanorods could be in situ dissolved owing to the generated alkaline and acidic environments during hydrothermal coating of SnO 2 nanocrystals and hydrothermal carbonization of glucose, respectively. When utilized as an anode material in lithium-ion batteries, the carbon-coated SnO 2 nanotubes manifests markedly enhanced Li-storage capabilities in terms of specific capacity and cycling stability in comparison with bare SnO 2 nanocrystals. - Graphical abstract: Display Omitted - Highlights: • C-coated SnO 2 nanotubes prepared via facile ZnO-nanorod-templated hydrothermal route. • Unique morphological and structural features toward lithium storage. • Enhanced Li-storage performance in terms of specific capacity and cycling stability

Harvesting energy from the counterbalancing (weaving) movement in bicycle riding.

Science.gov (United States)

Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank

2012-01-01

Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

Harvesting Energy from the Counterbalancing (Weaving Movement in Bicycle Riding

Directory of Open Access Journals (Sweden)

Shashank Priya

2012-07-01

Full Text Available Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle’s handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

Planning, implementing and evaluating a social and communication skills course for riding instructors

OpenAIRE

Seefeld, Annika

2016-01-01

Social and emotional skills are very important for effective coaching. As research in this field is still very limited, the purpose of this study was to plan, implement and evaluate a course teaching social and emotional skills to riding instructors. The objective of this research project was to analyse the usefulness and feasibility of a social and communication skills course for riding instructors. The present research study is an educational action research case study approa...

Advanced fault ride-through control of DFIG based wind turbines including grid connection via VSC-HVDC

Energy Technology Data Exchange (ETDEWEB)

Feltes, Christian

2012-07-01

With the growing renewable energy share in the power generation mix it becomes inevitable that also these new generation technologies participate on the provision of grid services to guarantee stable operation of the grid, especially when one considers the decreasing number of conventional power plants in operation as a result of the expansion of wind based generation plants. These so-called ancillary services include frequency / active power control, voltage / reactive power control and fault ride-through (FRT) with fast voltage control and are stipulated in modern grid codes. In the context of this thesis advanced control algorithms have been developed for wind turbines based on doubly-fed induction generator (DFIG) to allow safe FRT during symmetrical and unsymmetrical faults. This covers the control for conventional AC grid connection as well as for the connection through voltage source converter (VSC) based high voltage direct current transmission (HVDC). Currently, the DFIG is the most used generator technology in modem wind turbines, since it combines a relatively simple slip-ring induction machine with a frequency converter rated to only approx. 30% of the total power. This makes the DFIG a cost-effective concept, which offers a variable speed range and a high degree of flexibility in control. However, due to the direct coupling of the generator stator circuit to the grid, grid faults are a special challenge for the frequency converter, its protection circuits and control algorithms. As base for the detailed evaluation of the impact of grid faults to the DFIG, this thesis contains the analytical derivation of the DFIG short circuit currents under consideration of frequency converter control. The DFIG concept presented in this thesis makes use of a DC chopper in the frequency converter, which allows safe FRT with grid voltage support through both converter sides. The developed control contains a new algorithm for a clear separation and control of positive

Enhancing Financial Capability and Inclusion in the Philippines : A Demand-Side Survey

OpenAIRE

World Bank Group

2015-01-01

In response to a request of the Bangko Sentral ng Pilipinas (BSP) and as part of a broader engagement on enhancing financial consumer protection and education in the Philippines, the World Bank has implemented a financial capability survey. Financial inclusion, financial literacy and consumer protection are important priorities for the BSP and the Philippines government. Consumer protectio...

The Theory of Dynamic Public Transit Priority with Dynamic Stochastic Park and Ride

OpenAIRE

Zhu, Chengming; Chen, Yanyan; Ma, Changxi

2014-01-01

Public transit priority is very important for relieving traffic congestion. The connotation of dynamic public transit priority and dynamic stochastic park and ride is presented. Based on the point that the travel cost of public transit is not higher than the travel cost of car, how to determine the level of dynamic public transit priority is discussed. The traffic organization method of dynamic public transit priority is introduced. For dynamic stochastic park and ride, layout principle, scal...

mitigating mitigating free riding in peer-to-peer networks

African Journals Online (AJOL)

eobe

The performance of peer-to-peer systems is based on the quality and quantity of resource contributions from peer systems ... riding [3]. There are several measurement studies ...... J. S. Hua, D. C. Huang, S M Yen, and C. W. Chena, “A dynamic.

A Study on Coexistence Capability Evaluations of the Enhanced Channel Hopping Mechanism in WBANs

Directory of Open Access Journals (Sweden)

Zhongcheng Wei

2017-01-01

Full Text Available As an important coexistence technology, channel hopping can reduce the interference among Wireless Body Area Networks (WBANs. However, it simultaneously brings some issues, such as energy waste, long latency and communication interruptions, etc. In this paper, we propose an enhanced channel hopping mechanism that allows multiple WBANs coexisted in the same channel. In order to evaluate the coexistence performance, some critical metrics are designed to reflect the possibility of channel conflict. Furthermore, by taking the queuing and non-queuing behaviors into consideration, we present a set of analysis approaches to evaluate the coexistence capability. On the one hand, we present both service-dependent and service-independent analysis models to estimate the number of coexisting WBANs. On the other hand, based on the uniform distribution assumption and the additive property of Possion-stream, we put forward two approximate methods to compute the number of occupied channels. Extensive simulation results demonstrate that our estimation approaches can provide an effective solution for coexistence capability estimation. Moreover, the enhanced channel hopping mechanism can significantly improve the coexistence capability and support a larger arrival rate of WBANs.

Demonstration of load rating capabilities through physical load testing : Sioux County bridge case study.

Science.gov (United States)

2013-08-01

The objective of this work, Pilot Project - Demonstration of Capabilities and Benefits of Bridge Load Rating through Physical Testing, was to demonstrate the capabilities for load testing and rating bridges in Iowa, study the economic benefit of perf...

Demonstration of load rating capabilities through physical load testing : Johnson County bridge case study.

Science.gov (United States)

2013-08-01

The objective of this work, Pilot Project - Demonstration of Capabilities and Benefits of Bridge Load Rating through Physical Testing, was to demonstrate the capabilities for load testing and rating bridges in Iowa, study the economic benefit of perf...

Demonstration of load rating capabilities through physical load testing : Ida County bridge case study.

Science.gov (United States)

2013-08-01

The objective of this work, Pilot Project - Demonstration of Capabilities and Benefits of Bridge Load Rating through Physical Testing, was to demonstrate the capabilities for load testing and rating bridges in Iowa, study the economic benefit of perf...

Ride control of surface effect ships using distributed control

Directory of Open Access Journals (Sweden)

Asgeir J. Sørensen

1994-04-01

Full Text Available A ride control system for active damping of heave and pitch accelerations of Surface Effect Ships (SES is presented. It is demonstrated that distributed effects that are due to a spatially varying pressure in the air cushion result in significant vertical vibrations in low and moderate sea states. In order to achieve a high quality human comfort and crew workability it is necessary to reduce these vibrations using a control system which accounts for distributed effects due to spatial pressure variations in the air cushion. A mathematical model of the process is presented, and collocated sensor and actuator pairs are used. The process stability is ensured using a controller with appropriate passivity properties. Sensor and actuator location is also discussed. The performance of the ride control system is shown by power spectra of the vertical accelerations obtained from full scale experiments with a 35 m SES.

Riding Pontic--Aesthetic Journey Aesthetic Goal.

Science.gov (United States)

Rohilla, Byajit Kumar; Choudhary, Shweta; Manisha, Kukreja; Walia, Pawanjit Singh; Nafria, Anil

2015-01-01

The increasing concern for esthetics during the orthodontic treatment can be measured by the increasing popularity ofaesthetic brackets, lingual technique, smaller sized metal brackets, and clear alignment therapy. Many clients, especially adolescents, are self-conscious about their appearance in social and professional situations, and they refuse to tolerate the inevitable "black holes" of edentulous spaces during orthodontic treatment. This article describes the use, fabrication, modifications, and shortcomings of riding pontics; and illustrates how their use provides aesthetic, psychological and functional benefits.

Ride performance of a high speed rail vehicle using controlled semi active suspension system

Science.gov (United States)

Sharma, Sunil Kumar; Kumar, Anil

2017-05-01

The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

Free riding and the provision of candy bars

NARCIS (Netherlands)

Haan, M.A.; Kooreman, P.

A wealth of experimental literature studies the effect of repetition and group size on the extent of free riding in the provision of public goods. In this paper, we use data from honor systems for candy bars in 166 firms to test whether such effects can be found outside the laboratory. We find that

A novel "hitch-and-ride" deep biliary cannulation method during rendezvous endoscopic ultrasound-guided ERCP technique.

Science.gov (United States)

Nakai, Yousuke; Isayama, Hiroyuki; Matsubara, Saburo; Kogure, Hirofumi; Mizuno, Suguru; Hamada, Tsuyoshi; Takahara, Naminatsu; Nakamura, Tomoka; Sato, Tatsuya; Takeda, Tsuyoshi; Hakuta, Ryunosuke; Ishigaki, Kazunaga; Saito, Kei; Tada, Minoru; Koike, Kazuhiko

2017-10-01

Background and study aim Endoscopic ultrasound-guided rendezvous (EUS-RV) is increasingly reported as a treatment option after failed endoscopic retrograde cholangiopancreatography. We developed a novel "hitch-and-ride" catheter for biliary cannulation to reduce the risk of guidewire loss during EUS-RV. Patients and methods We retrospectively evaluated safety and technical success of EUS-RV between June 2011 and May 2016. Biliary cannulation during EUS-RV using three methods - over-the-wire, along-the-wire, and hitch-and-ride - were compared. Results A total of 30 EUS-RVs were attempted and the technical success rate was 93.3 %, with two failures (one bile duct puncture and one guidewire insertion). After 28 cases of successful guidewire passage, cannulation was attempted by the over-the-wire (n = 13), along-the-wire (n = 4) or hitch-and-ride (n = 11) method. Only the hitch-and-ride method achieved biliary cannulation without guidewire loss or conversion to the other methods. Time to cannulation was shorter with the hitch-and-ride method (4 minutes) than with over-the-wire and along-the-wire methods (9 and 13 minutes, respectively). The adverse event rate of EUS-RV was 23.3 %. Conclusion A novel hitch-and-ride catheter was feasible for biliary cannulation after EUS-RV. © Georg Thieme Verlag KG Stuttgart · New York.

A Capabilities-Friendly Conceptualisation of Flourishing in and through Education

Science.gov (United States)

Wilson-Strydom, Merridy; Walker, Melanie

2015-01-01

This article explores what it means to flourish in and through education and why we should position such flourishing as an issue of morality. We draw on the capabilities approach (CA) advanced by Amartya Sen and Martha Nussbaum and locate the argument in the practical context of higher education (HE) in unequal societies. We use qualitative data…

Resolved-particle simulation by the Physalis method: Enhancements and new capabilities

Energy Technology Data Exchange (ETDEWEB)

Sierakowski, Adam J., E-mail: sierakowski@jhu.edu [Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Prosperetti, Andrea [Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Faculty of Science and Technology and J.M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

2016-03-15

We present enhancements and new capabilities of the Physalis method for simulating disperse multiphase flows using particle-resolved simulation. The current work enhances the previous method by incorporating a new type of pressure-Poisson solver that couples with a new Physalis particle pressure boundary condition scheme and a new particle interior treatment to significantly improve overall numerical efficiency. Further, we implement a more efficient method of calculating the Physalis scalar products and incorporate short-range particle interaction models. We provide validation and benchmarking for the Physalis method against experiments of a sedimenting particle and of normal wall collisions. We conclude with an illustrative simulation of 2048 particles sedimenting in a duct. In the appendix, we present a complete and self-consistent description of the analytical development and numerical methods.

Capturing Firms’ Heterogeneity through Marketing and IT Capabilities in SMEs

Directory of Open Access Journals (Sweden)

María A. Ramón-Jerónimo

2017-11-01

Full Text Available To achieve sustainability, firms capable of surviving economic recessions is of key relevance; the capabilities that firms need to face dynamic environments remain an open question. In this work, a new procedure is proposed to capture firms’ heterogeneity with regard to the capabilities they possess in operating efficiently in dynamic environments. This approach enables the identification of the classes of firms that develop efficiency with a specific integration of resources. While the literature has most often measured firm capabilities using subjective measures, this study suggests the use of Data Envelopment Analysis to capture the ability to transform resources into outcomes and of Latent Class Regression to capture differences across firms that explain firms’ heterogeneity in the way they perform. By combining these two techniques, this work presents a way to identify those firms that need to invest in and develop certain capabilities. This work analyses a large dataset of manufacturing Small Medium Enterprises (SMEs extracted from the Business and Strategy survey provided by Fundación de la Sociedad Estatal de Participaciones Industriales( SEPI in Spain. The dataset used enfolds 10,960 observations from 2048 firms during the period 1994–2011. The complete dataset has been employed to calculate manufacturing firms’ efficiency. In a second step, data were cleaned to eliminate outliers, and to identify SMEs and observations with records of IT capabilities. As a result, 329 manufacturing SMEs were analysed to capture their heterogeneity. The results contribute to the current literature by explaining how manufacturing SMEs show a different need in their development of capabilities to be efficient and adapt to environmental changes. While approximately 20% of firms analysed really take advantage of recessions through their investment in R&D, the remaining 80% need to adjust their size or invest in IT capabilities to become competitive

Joint Recovery and Distribution System (JRaDS) Joint Capability Technology Demonstration (JCTD), Technical Manager’s Report

Science.gov (United States)

2013-09-01

loading and off-loading cargo. • Repositionable wheels ( moveable bogie) maximize its load-bearing capabilities and increase maneuverability and vehicle...29 large hydraulic cylinder that powers the moveable bogey is able to move the tractor-trailer combination longitudinally in a very controlled manner...a lower ride height enables proper clearance levels for going under bridges . For off-road operation, a large suspension travel is needed and there

Antenna-assisted enhanced transmission through subwavelength nanoholes

DEFF Research Database (Denmark)

Xiao, Sanshui; Peng, Liang; Mortensen, Asger

2010-01-01

By structural engineering of sub-wavelength apertures, we numerically demonstrate that transmission through apertures can be significantly enhanced. Based on equivalent circuit theory analysis, structured apertures are obtained with a 1900-fold transmission enhancement factor. We show that the en......By structural engineering of sub-wavelength apertures, we numerically demonstrate that transmission through apertures can be significantly enhanced. Based on equivalent circuit theory analysis, structured apertures are obtained with a 1900-fold transmission enhancement factor. We show...

Mitigating Free Riding in Peer-To-Peer Networks: Game Theory ...

African Journals Online (AJOL)

Mitigating Free Riding in Peer-To-Peer Networks: Game Theory Approach. ... In this paper, we model the interactions between peers as a modified gift giving game and proposed an utility exchange incentive ... AJOL African Journals Online.

The Capabilities Approach: Fostering contexts for enhancing mental health and wellbeing across the globe.

Science.gov (United States)

White, Ross G; Imperiale, Maria Grazia; Perera, Em

2016-05-05

Concerted efforts have been made in recent years to achieve equity and equality in mental health for all people across the globe. This has led to the emergence of Global Mental Health as an area of study and practice. The momentum that this has created has contributed to the development, implementation and evaluation of services for priority mental disorders in many low- and middle-income countries.This paper discusses two related issues that may be serving to limit the success of mental health initiatives across the globe, and proposes potential solutions to these issues. First, there has been a lack of sophistication in determining what constitutes a 'good outcome' for people experiencing mental health difficulties. Even though health is defined and understood as a state of 'wellbeing' and not merely an absence of illness, mental health interventions tend to narrowly focus on reducing symptoms of mental illness. The need to also focus more broadly on enhancing subjective wellbeing is highlighted. The second limitation relates to the lack of an overarching theoretical framework guiding efforts to reduce inequalities and inequities in mental health across the globe. This paper discusses the potential impact that the Capabilities Approach (CA) could have for addressing both of these issues. As a framework for human development, the CA places emphasis on promoting wellbeing through enabling people to realise their capabilities and engage in behaviours that they subjectively value. The utilization of the CA to guide the development and implementation of mental health interventions can help Global Mental Health initiatives to identify sources of social inequality and structural violence that may impede freedom and individuals' opportunities to realise their capabilities.

Power-Up: Exploration and Play in a Novel Modified Ride-On Car for Standing.

Science.gov (United States)

Logan, Samuel W; Lobo, Michele A; Feldner, Heather A; Schreiber, Melynda; MacDonald, Megan; Winden, Haylee N; Stoner, Tracy; Galloway, James Cole

2017-01-01

The purpose of this study was to compare the physical activity and play behaviors of preschoolers without disabilities and 1 preschooler with physical disability. Participants were 42 preschoolers without disabilities and 1 preschooler with physical disability (Child A). Child A used either crutches or a modified ride-on car while in the gymnasium and playground. In the gymnasium, Child A engaged in less solitary play and more parallel play while using the modified ride-on car compared with crutches. On the playground, Child A engaged in more sitting and less running while using crutches compared with preschoolers without disabilities. On the playground, Child A engaged in more peer interaction and less teacher interaction when using the modified ride-on car compared with crutches. For children with disabilities who may use assistive devices, clinicians, families, and teachers are encouraged to embrace a "right device, right time, right place" approach.

Advanced Control Strategy of DFIG Wind Turbines for Power System Fault Ride Through

DEFF Research Database (Denmark)

Yang, Lihui; Xu, Zhao; Ostergaard, Jacob

2012-01-01

, the rotor side controller can convert the imbalanced power into the kinetic energy of the WT by increasing its rotor speed, when a low voltage due to a grid fault occurs at, e.g., the point of common coupling (PCC). The proposed grid side control scheme introduces a compensation term reflecting...... the oscillations in the stator and rotor currents and the DC bus voltage. The effectiveness of the proposed control strategy has been demonstrated through various simulation cases. Compared with conventional crowbar protection, the proposed control method can not only improve the LVRT capability of the DFIG WT......, but also help maintaining continuous active and reactive power control of the DFIG during the grid faults....

Trustworthy reconfigurable systems enhancing the security capabilities of reconfigurable hardware architectures

CERN Document Server

Feller, Thomas

2014-01-01

?Thomas Feller sheds some light on trust anchor architectures fortrustworthy reconfigurable systems. He is presenting novel concepts enhancing the security capabilities of reconfigurable hardware.Almost invisible to the user, many computer systems are embedded into everyday artifacts, such as cars, ATMs, and pacemakers. The significant growth of this market segment within the recent years enforced a rethinking with respect to the security properties and the trustworthiness of these systems. The trustworthiness of a system in general equates to the integrity of its system components. Hardware-b

Optimizing itineraries in public transportation with walks between rides

NARCIS (Netherlands)

de Jonge, Bram; Teunter, Ruud H.

We study the problem of finding an optimal itinerary to travel from a starting location to a destination location using public transport, where we allow travelers to alternate rides with (short) walks. The main difference with previous research is that we take all possible walks that a traveler can

Traffic routing for multicomputer networks with virtual cut-through capability

Science.gov (United States)

Kandlur, Dilip D.; Shin, Kang G.

1992-01-01

Consideration is given to the problem of selecting routes for interprocess communication in a network with virtual cut-through capability, while balancing the network load and minimizing the number of times that a message gets buffered. An approach is proposed that formulates the route selection problem as a minimization problem with a link cost function that depends upon the traffic through the link. The form of this cost function is derived using the probability of establishing a virtual cut-through route. The route selection problem is shown to be NP-hard, and an algorithm is developed to incrementally reduce the cost by rerouting the traffic. The performance of this algorithm is exemplified by two network topologies: the hypercube and the C-wrapped hexagonal mesh.

Free Riding or Trust?

DEFF Research Database (Denmark)

Svendsen, Gert Tinggaard; Nilsson, Jerker

2011-01-01

It is often observed that members have little interest in monitoring their cooperatives. One explanation is that the members are free-riders, hoping that others will perform the task. Another explanation is that the weak member interest is a consequence of members having trust in the leadership....... These competing explanations refer to the theory of collective action and the social capital paradigm, respectively, and may be linked to the classical Gesellschaft and Gemeinschaft concepts. Hence, one may expect free-rider behavior when conditions of Gesellschaft exist and trustful behavior when Gemeinschaft...... conditions rule. These propositions get support from five studies of members’ readership of their cooperatives’ annual reports. In large and heterogeneous memberships there is free-riding behavior, which explains the members’ low interest in governing their cooperatives. To a limited extent a membership may...

Effects of 4 Weeks of Horseback Riding on Anxiety, Depression, and Self-Esteem in Children with Attention Deficit Hyperactivity Disorder

Directory of Open Access Journals (Sweden)

Wi-Young So

2017-09-01

Full Text Available Background and Objective: There is no report on the effects of horseback riding on children with attention deficit hyperactivity disorder (ADHD. Therefore, the purpose of this study was to determine the effects of 4 weeks of horseback riding on anxiety, depression, self-esteem, attention, and learning disorder in children with ADHD. Material and Methods: Subjects comprised a convenience sample of 10 children aged 10-12 years with ADHD and 10 children without ADHD. Horseback riding sessions were performed 2 times (40 minutes/day per week for 4 weeks. Before and after the horseback riding program, we measured the children’s anxiety, depression, self-esteem, attention, and learning disorder. The pre-test and post-test scores were analyzed with repeated-measures analysis of variance. Results: After participating in the 4-week horseback riding program, anxiety (p = 0.013, depression (p = 0.007, attention (p < 0.001, and learning disorder (p < 0.001 were significantly improved in the ADHD group compared to the control group. However, self-esteem was not significantly different between the two groups (p=0.096. Conclusion: These results indicate that the 4-week horseback riding program used in this study was very effective for significantly improving anxiety, depression, and attention in children with ADHD.

Saturday Subway Ride: A Report on the Initial Tryout.

Science.gov (United States)

Quilling, Mary R.; And Others

"Saturday Subway Ride," a program designed to teach pupils creative thinking techniques and positive attitudes toward creative ideas, is a 92-page workbook in a story-exercise format. Secondary objectives for the product include improving verbal fluency and creative writing. Three classrooms 61 sixth graders and 34 fifth graders at two…

Assessment of a rail vehicle running with the damaged wheel on a ride comfort for passengers

Directory of Open Access Journals (Sweden)

Dižo Ján

2018-01-01

Full Text Available In certain conditions rail vehicles wheels can be during operation damaged. Then, the profile of wheels is no longer circular, but it is changed depending on the type and severity of defects. When such rail vehicle with the damaged wheel operates, the quality of a ride comfort for passenger is degraded. This article is focused on the assessment of ride comfort for passenger based on results obtained from dynamic analyses. Simulations and calculations were carried out in commercial multibody software. In our research we considered one type of the railway wheel untrueness – wheel-flat. This type of wheel damaging is relatively common and has such influence on the ride comfort for passenger worsening, which needs to be detected and investigated.

Enhancing optical response of graphene through stochastic resonance

Science.gov (United States)

Ying, Lei; Huang, Liang; Lai, Ying-Cheng

2018-04-01

Enhancing the optical response of graphene is a topic of interest with applications in optoelectronics. Subject to light irradiation, graphene can exhibit nontrivial topologically insulating states, effectively turning itself into a Floquet topological insulator due to the time periodicity of the external driving. We find that, when random disorder is present, its interplay with the topologically insulating states can have a dramatic effect on electronic transport through graphene. In particular, we consider the prototypical setting where a graphene nanoribbon is irradiated by circularly polarized light, where the length of the nanoribbon is sufficiently long so that evanescent states have little effect on transport. We uncover a resonance phenomenon in which the conductance is enhanced as the disorder strength is increased from zero, reaches a maximum value for an optimal level of disorder, and decreases as the disorder is strengthened further. With respect to its value at the zero-disorder strength, the maximum conductance value can be as much as 50 % higher. Qualitatively, this can be understood as a result of the dynamical interplay between disorder and Floquet states (channels) generated by light irradiation. Quantitatively, the resonance phenomenon can be explained in the framework of Born theory, where the disorder reorganizes the Floquet Hamiltonian and enhances the effective coupling between the adjacent Floquet conducting channels. That is, disorder is capable of promoting both photon absorption and emission, leading to significant enhancement of nonequilibrium electronic transport. We demonstrate the robustness of the resonance phenomenon by investigating the effects of spatial symmetry breaking on transport and provide an understanding based on analyzing the behavior of the density of states of the Floquet channels.

Ride-sharing business model for sustainability in developing country: Case Study Nebengers, Indonesia

Science.gov (United States)

Asirin, Asirin; Azhari, Danang

2018-05-01

The growth of population and urban economy increased the need for humans’ mobility to support their activities. On the other hand, online Information and Communication Technology (ICT) is growing rapidly and more affordable. Within few years, there is some sharing economy business formed by using online platform. This condition brings through the emergence of ride-sharing business model using an online platform which can be beneficial to sustainability. This research aims to explore one of ridesharing business models which use the online platform and its impact on sustainability. This research used the procedure of case study method with a single case study of Nebengers. This research explores the case study with the scope of this research is limited by using several conceptual frameworks, they are sharing economy business model, four elements of a business model for sustainability (BMfS), Social Construction of Technology (SCoT), sustainable mobility and agency theory. Nebengers is a sharing economy business using online platform that historically can be explained using Social Construction of Technology (SCoT) Theory. There are conflicts between nebengers entrepreneur and the city government. Nebengers disrupts traditional and formal public transportation services which are managed by the government. However, nebengers also contributes to achieve the city government goal in developing sustainable mobility. The future challenge is how to arrange ride-sharing collaborative governance business model for sustainability in the cities in Indonesia.

Developing the P2/6 methodology [to assess the security capability of modern distributed generation

Energy Technology Data Exchange (ETDEWEB)

Allan, Ron; Strbac, Goran; Djapic, Predrag; Jarrett, Keith [Manchester Univ. Inst. of Science and Technology, Manchester (United Kingdom)

2004-04-29

The main objective of the project was to use the methodology developed in the previous Methodology project (ETSU/FES Project K/EL/00287) to assess the security capability of modern distributed generation in order to review Table 2 and related text of Engineering Recommendation P2/5, and to propose information and results that could be used to create a new P2/6 that takes into account modern types of generating units; unit numbers; unit availabilities; and capacities. Technical issues raised in the previous study but held over until this project include: Treatment of single unit generation systems; Effect of shape of load duration curves; Persistence of intermittent generation, T{sub m}; Time resolution of intermittent generation output profiles; Ride-through capability; Risk to loss of supply. Three main ways of implementing the methodology were recommended: Look-up table(s), Graphical, and Computer program. The specification for the computer program was to produce a simple spreadsheet application package that an engineer with a reasonably knowledge of the approach could use. This prototype package has been developed in conjunction with Workstream 3. Its objective is to calculate the capability contribution to security of supply from distributed generation connected to a particular demand group. The application has been developed using Microsoft Excel and Visual Basic for Applications. New Tables for inclusion in P2/6 are included. (UK)

Cognitive motivations of free riding and cooperation and impaired strategic decision making in schizophrenia during a public goods game.

Science.gov (United States)

Chung, Dongil; Kim, Yang-Tae; Jeong, Jaeseung

2013-01-01

Schizophrenia is generally characterized by various positive and negative symptoms that are accompanied by significant social dysfunction. Various researchers investigated the functional impairments in schizophrenia including impaired theory of mind (TOM), poor integration of affective and cognitive information, and malfunctioning of adaptive and strategic learning process. However, most of the studies were limited to simplified cognitive tests or computerized choice games that exclude real social interaction. The aim of the current study was to investigate human strategies based on the incentives and particularly the cognitive and emotional motivations of free riding. We examined the decision patterns of 41 healthy subjects (HSs) and 37 schizophrenia patients (SZ) during the public goods game (PGG), one of the games simulating human cooperation and free riding in group interactions. Strategic decision processes during the iterative binary PGG were assessed in terms of cognitive understanding, loss sensitivity, and TOM. We found that greed and loss sensitivity both motivated free-riding behavior in the HS, but that they were more vulnerable to greedy incentives than to possible loss. More significantly, the SZ clearly displayed a lower prevalence of free riding and distinct decision patterns from HS. Nonstrategic and unexpectedly low free ridings in the SZ likely arise from poor integration of cognitive and affective information. We suggest that loss sensitivity and TOM as well as cognitive understanding are involved in regulation of the free riding and cooperative behavior.

Improving Vehicle Ride and Handling Using LQG CNF Fusion Control Strategy for an Active Antiroll Bar System

Directory of Open Access Journals (Sweden)

N. Zulkarnain

2014-01-01

Full Text Available This paper analyses a comparison of performance for an active antiroll bar (ARB system using two types of control strategy. First of all, the LQG control strategy is investigated and then a novel LQG CNF fusion control method is developed to improve the performances on vehicle ride and handling for an active antiroll bar system. However, the ARB system has to balance the trade-off between ride and handling performance, where the CNF consists of a linear feedback law and a nonlinear feedback law. Typically, the linear feedback is designed to yield a quick response at the initial stage, while the nonlinear feedback law is used to smooth out overshoots in the system output when it approaches the target reference. The half car model is combined with a linear single track model with roll dynamics which are used for the analysis and simulation of ride and handling. The performances of the control strategies are compared and the simulation results show the LQG CNF fusion improves the performances in vehicle ride and handling.

Cooperate or Free Ride?

DEFF Research Database (Denmark)

Hansen, Per H.

2012-01-01

of international cooperation. On the other hand, the evidence seems to confirm Kindleberger's hypothesis that small countries were free riding during the international financial crisis of 1931, and that therefore there is a need for some coordinating mechanism, or a hegemon, in such crises....... in the establishment of the BIS and free riders in the Austrian crisis, even though there were marked differences in their attitude to international cooperation. These results run counter to the views of those International Political Economy (IPE) theorists who argue that small states should be in favour......In this article, I discuss the role of the three Scandinavian central banks in the establishment of the Bank for International Settlements (BIS) in 1930, and in the international lender of last resort operation towards Austria in 1931. I argue that small central banks were reluctant supporters...

The choice of Park & Ride Facilities: an analysis using a context-dependent hierarchical choice experiment

OpenAIRE

Heijden, R.E.C.M. van der; Molin, E.J.E.; Timmermans, H.J.P.

2004-01-01

Park and Ride facilities have been proposed in several countries to alleviate the accessibility problems in cities. Despite growing accessibility problems, these facilities do not seem to attract the expected number of car drivers and are under-used. In an attempt to measure consumer evaluations of the attributes of Park and Ride facilities, a stated choice experiment, based on the method of hierarchical information integration, was conducted in the city of Nijmegen, The Netherlands. This pap...

Research on enhancement of natural circulation capability in lead–bismuth alloy cooled reactor by using gas-lift pump

Energy Technology Data Exchange (ETDEWEB)

Zuo, Juanli, E-mail: Jenyzuo@163.com; Tian, Wenxi, E-mail: wxtian@mail.xjtu.edu.cn; Chen, Ronghua, E-mail: ronghua.chen@stu.xjtu.edu.cn; Qiu, Suizheng; Su, Guanghui, E-mail: ghsu@mail.xjtu.edu.cn

2013-10-15

Highlights: • The gas-lift pump has been adopted to enhance the natural circulation capability. • LENAC code is developed in my study. • The calculation results by LENAC code show good agreement with experiment results. • Gas mass flow rate, bubble diameter, rising pipe length are important parameters. -- Abstract: The gas-lift pump has been adopted to enhance the natural circulation capability in the type of lead–bismuth alloy cooled reactors such as Accelerator Driven System (ADS) and Liquid–metal Fast Reactor (LMFR). The natural circulation ability and the system safety are obviously influenced by the two phase flow characteristics of liquid metal–inert gas. In this study, LENAC (LEad bismuth alloy NAtural Circulation capability) code has been developed to evaluate the natural circulation capability of lead–bismuth cooled ADS with gas-lift pump. The drift flow theory, void fraction prediction model and friction pressure drop prediction model have been incorporated into LENAC code. The calculation results by LENAC code show good agreement with experiment results of CIRCulation Experiment (CIRCE) facility. The effects of the gas mass flow rate, void fraction, gas quality, bubble diameter and the rising pipe height or the potential difference between heat exchanger and reactor core on natural circulation capability of gas-lift pump have been analyzed. The results showed that in bubbly flow pattern, for a fixed value of gas mass flow rate, the natural circulation capability increased with the decrease of the bubble diameter. In the bubbly flow, slug flow, churn flow and annular flow pattern, with the gas mass flow rate increasing, the natural circulation capability initially increased and then declined. And the flow parameters influenced the thermal hydraulic characteristics of the reactor core significantly. The present work is helpful for revealing the law of enhancing the natural circulation capability by gas-lift pump, and providing theoretical

An approach to high speed ship ride quality simulation

Science.gov (United States)

Malone, W. L.; Vickery, J. M.

1975-01-01

The high speeds attained by certain advanced surface ships result in a spectrum of motion which is higher in frequency than that of conventional ships. This fact along with the inclusion of advanced ride control features in the design of these ships resulted in an increased awareness of the need for ride criteria. Such criteria can be developed using data from actual ship operations in varied sea states or from clinical laboratory experiments. A third approach is to simulate ship conditions using measured or calculated ship motion data. Recent simulations have used data derived from a math model of Surface Effect Ship (SES) motion. The model in turn is based on equations of motion which have been refined with data from scale models and SES of up to 101 600-kg (100-ton) displacement. Employment of broad band motion emphasizes the use of the simulators as a design tool to evaluate a given ship configuration in several operational situations and also serves to provide data as to the overall effect of a given motion on crew performance and physiological status.

Hospital-treated injuries from horse riding in Victoria, Australia: time to refocus on injury prevention?

Science.gov (United States)

O'Connor, Siobhán; Hitchens, Peta L; Fortington, Lauren V

2018-01-01

The most recent report on hospital-treated horse-riding injuries in Victoria was published 20 years ago. Since then, injury countermeasures and new technology have aimed to make horse riding safer for participants. This study provides an update of horse-riding injuries that required hospital treatment in Victoria and examines changes in injury patterns compared with the earlier study. Horse-riding injuries that required hospital treatment (hospital admission (HA) or emergency department (ED) presentations) were extracted from routinely collected data from public and private hospitals in Victoria from 2002-2003 to 2015-2016. Injury incidence rates per 100 000 Victorian population per financial year and age-stratified and sex-stratified injury incidence rates are presented. Poisson regression was used to examine trends in injury rates over the study period. ED presentation and HA rates were 31.1 and 6.6 per 100 000 person-years, increasing by 28.8% and 47.6% from 2002 to 2016, respectively. Female riders (47.3 ED and 10.1 HA per 100 000 person-years) and those aged between 10 and 14 years (87.8 ED and 15.7 HA per 100 000 person-years) had the highest incidence rates. Fractures (ED 29.4%; HA 56.5%) and head injuries (ED 15.4%; HA 18.9%) were the most common injuries. HA had a mean stay of 2.6±4.1 days, and the mean cost per HA was $A5096±8345. Horse-riding injuries have remained similar in their pattern (eg, types of injuries) since last reported in Victoria. HA and ED incidence rates have increased over the last 14 years. Refocusing on injury prevention countermeasures is recommended along with a clear plan for implementation and evaluation of their effectiveness in reducing injury.

Interactive computer-enhanced remote viewing system with data fusion capabilities

International Nuclear Information System (INIS)

Walter, T.J.

1997-01-01

Robotic missions will increasingly involve sending autonomous and semiautonomous vehicles into unstructured work environments. Mission success will often depend on the ability to accurately map scenes, to combine information from a variety of sensor types, to convey the three-dimensional (3-D) characteristics of these spaces to operators, and to construct geometric model task planning and collision avoidance. To meet these needs, an interactive computer-enhanced remote viewing system (ICERVS) has been developed with general-purpose capabilities for data visualization and geometric modeling. ICERVS has been augmented with software that enables fusing data from multiple mapping sensors and poses to reduce the error effects in individual data sets and improve the mapping accuracy of a work space

Benefits of Hippotherapy and Horse Riding Simulation Exercise on Healthy Older Adults: A Systematic Review.

Science.gov (United States)

Hilliere, Camille; Collado-Mateo, Daniel; Villafaina, Santos; Duque-Fonseca, Paulo; Parraça, José A

2018-04-05

To provide an up-to-date research analysis on equine-assisted therapies and horse riding simulation exercise in older adults, and to suggest future directions in clinical practice and research. TYPE: Systematic review. A comprehensive search of studies was performed in 4 electronic databases (Cochrane, PubMed, PEDro, and Web of Science) regarding the effects of equine-assisted therapies and horse riding simulation exercise in older adults. Eight articles were selected, 5 of them focused on hippotherapy, 2 on horse riding simulation, and a single article that used the 2 types of therapy. PRISMA guidelines were followed for the data extraction process. The studies were all randomized controlled trials, but not double-blind, so they were classified as level of evidence B. Duration of hippotherapy programs ranged from 8-12 weeks. Sessions lasted between 15 and 60 minutes and were performed 2-5 times per week. Interventions using a horse simulator spanned 8 weeks and were conducted for 20 minutes 5 times per week. Results indicate that hippotherapy might improve balance, mobility, gait ability, and muscle strength, as well as could induce hormonal and cerebral activity changes in healthy older adults. Benefits of horse riding simulation could be limited to physical fitness and muscular activity. ▪▪▪. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Collaborative Capability in Coworking Spaces: Convenience Sharing or Community Building?

Directory of Open Access Journals (Sweden)

Marcelo F. Castilho

2017-12-01

Full Text Available This study explores the development of collaborative capability in coworking spaces. It is based on the perception of collaboration among 31 coworking founders, community managers, and coworkers of those spaces. In-depth interviews around the meaning of collaboration and its challenges were conducted in 14 coworking spaces located in six Asian countries. A set of factors was identified and a model was proposed based on a set of four dimensions: enabling knowledge sharing, enhancing a creative field, enhancing an individual action for the collective, and supporting a collective action to an effective execution. The “Convenience Sharing” and “Community Building” coworking types based on Capdevila (2014 suggest different conditions under which collaborative capability develops. Convenience Sharing coworking spaces tend to foster collaborative capability through knowledge sharing and effective execution, whereas Community Building coworking spaces tend to foster collaborative capability by enhancing a creative field and individual action for the collective. Overall, this study contributes to a theoretical model for coworking spaces to help coworking founders and community managers make strategic decisions. The findings suggest that collaborative capability in coworking spaces depends on the interlacing of a set of factors along four dimensions that relate in varying degrees of intensity to a two-fold coworking space typology.

Effect of Health Education on the Riding Habits of Commercial ...

African Journals Online (AJOL)

METHODS: The intervention study was conducted among commercial motorcyclists in Uyo with controls from another town in Akwa Ibom State. Baseline information was collected from both groups on their riding habits. Motorcyclists in Uyo were educated on appropriate road safety practices. Data was collected from both ...

Fancy a ride?

CERN Multimedia

Anaïs Schaeffer

2014-01-01

This Sunday 7 September, don’t miss your chance to climb into a supercar, one of those exceptional machines that tear up the tracks and that you sometimes hear revving their engines on the motorway. The 2014 supercar experience day, organised by members of CERN, will allow car lovers to go for a ride in style and all for a good cause!   Supercars at the 2013 experience day. Photo: Kevin Mazzilli. If you have always dreamt of sitting in a Ferrari, feeling the vibrations of a Lamborghini, or losing yourself in the hushed calm of a classic car, don’t miss the supercar experience day taking place on Sunday, 7 September! This event has been organised by CERN’s own car enthusiasts, in collaboration with the charity Kumansansa – Children of Zambia, founded by two CERN members. It will take place for the third consecutive year in the car park of the Macumba leisure centre in Saint-Julien-en-Genevois (France). From 9.30 a.m. to 6 p.m., visitors old and young (c...

Enhanced CANDU 6 (EC6): a proven mid-sized reactor with fuel cycle capability

International Nuclear Information System (INIS)

Hopwood, J.; Soulard, M.; Hastings, I.J.

2011-01-01

Atomic Energy of Canada (AECL) is finalizing development of the Enhanced CANDU 6 (EC6), which incorporates the CANDU 6's well-proven features, and adds enhancements that make the reactor even more safe and easier to operate. The EC6 is the only mid-sized reactor (700 MWe class) with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. Changes are incremental and consistent with the CANDU 6 project approach. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. Containment and seismic capability are upgraded to meet modern standards. The first deployment of the EC6 is anticipated in Canada; international markets are also being pursued. AECL is performing a comprehensive review of the EC6 design in the wake of the Fukushima accident, will review lessons learned, and incorporate any necessary improvements into new build design. (author)

Enhanced CANDU 6 (EC6): a proven mid-sized reactor with fuel cycle capability

International Nuclear Information System (INIS)

Hopwood, J.; Soulard, M.; Hastings, I.J.

2011-01-01

Atomic Energy of Canada (AECL) is finalizing development of the Enhanced CANDU 6 (EC6), which incorporates the CANDU 6's well-proven features, and enhancements that make the reactor even more safe and easier to operate. The EC6 is the only mid-sized reactor (700 MWe class) with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. Changes are incremental and consistent with the CANDU 6 project approach. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. Containment and seismic capability are upgraded to meet modern standards. The first deployment of the EC6 is anticipated in Canada; international markets are also being pursued. AECL is performing a comprehensive review of the EC6 design in the wake of the Fukushima accident, will review lessons learned, and incorporate any necessary improvements into new build design. (author)

Exploring Spatiotemporal Patterns of Long-Distance Taxi Rides in Shanghai

Directory of Open Access Journals (Sweden)

Hangbin Wu

2017-11-01

Full Text Available Floating Car Data (FCD has been analyzed for various purposes in past years. However, limited research about the behaviors of taking long-distance taxi rides has been made available. In this paper, we used data from over 12,000 taxis during a six-month period in Shanghai to analyze the spatiotemporal patterns of long-distance taxi trips. We investigated these spatiotemporal patterns by comparing them with metro usage in Shanghai, in order to determine the extent and how the suburban trains divert the passenger flow from taxis. The results identified 12 pick-up and six drop-off hotspots in Shanghai. Overall, the pick-up locations were relatively more concentrated than the drop-off locations. Temporal patterns were also revealed. Passengers on long-distance taxi rides were observed to avoid the rush hours on the street as their first priority and tried to avoid the inconvenience of interchanges on the metro lines as their second priority.

Fused Reality for Enhanced Flight Test Capabilities

Science.gov (United States)

Bachelder, Ed; Klyde, David

2011-01-01

The feasibility of using Fused Reality-based simulation technology to enhance flight test capabilities has been investigated. In terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests, even when considering the fidelity and effectiveness of modern ground-based simulators. In addition to real-world cueing (vestibular, visual, aural, environmental, etc.), flight tests provide subtle but key intangibles that cannot be duplicated in a ground-based simulator. There is, however, a cost to be paid for the benefits of flight in terms of budget, mission complexity, and safety, including the need for ground and control-room personnel, additional aircraft, etc. A Fused Reality(tm) (FR) Flight system was developed that allows a virtual environment to be integrated with the test aircraft so that tasks such as aerial refueling, formation flying, or approach and landing can be accomplished without additional aircraft resources or the risk of operating in close proximity to the ground or other aircraft. Furthermore, the dynamic motions of the simulated objects can be directly correlated with the responses of the test aircraft. The FR Flight system will allow real-time observation of, and manual interaction with, the cockpit environment that serves as a frame for the virtual out-the-window scene.

Developing Alliance Capabilities

DEFF Research Database (Denmark)

Heimeriks, Koen H.; Duysters, Geert; Vanhaverbeke, Wim

This paper assesses the differential performance effects of learning mechanisms on the development of alliance capabilities. Prior research has suggested that different capability levels could be identified in which specific intra-firm learning mechanisms are used to enhance a firm's alliance...

Process capability improvement through DMAIC for aluminum alloy wheel machining

Science.gov (United States)

Sharma, G. V. S. S.; Rao, P. Srinivasa; Babu, B. Surendra

2017-07-01

This paper first enlists the generic problems of alloy wheel machining and subsequently details on the process improvement of the identified critical-to-quality machining characteristic of A356 aluminum alloy wheel machining process. The causal factors are traced using the Ishikawa diagram and prioritization of corrective actions is done through process failure modes and effects analysis. Process monitoring charts are employed for improving the process capability index of the process, at the industrial benchmark of four sigma level, which is equal to the value of 1.33. The procedure adopted for improving the process capability levels is the define-measure-analyze-improve-control (DMAIC) approach. By following the DMAIC approach, the C p, C pk and C pm showed signs of improvement from an initial value of 0.66, -0.24 and 0.27, to a final value of 4.19, 3.24 and 1.41, respectively.

Extending i-line capabilities through variance characterization and tool enhancement

Science.gov (United States)

Miller, Dan; Salinas, Adrian; Peterson, Joel; Vickers, David; Williams, Dan

2006-03-01

Continuous economic pressures have moved a large percent of integrated device manufacturing (IDM) operations either overseas or to foundry operations over the last 10 years. These pressures have left the IDM fabs in the U.S. with required COO improvements in order to maintain operations domestically. While the assets of many of these factories are at a very favorable point in the depreciation life cycle, the equipment and processes are constrained to the quality of the equipment in its original state and the degradation over its installed life. With the objective to enhance output and improve process performance, this factory and their primary lithography process tool supplier have been able to extend the usable life of the existing process tools, increase the output of the tool base, and improve the distribution of the CDs on the product produced. Texas Instruments Incorporated lead an investigation with the POLARIS ® Systems & Services business of FSI International to determine the sources of variance in the i-line processing of a wide array of IC device types. Data from the sources of variance were investigated such as PEB temp, PEB delay time, develop recipe, develop time, and develop programming. While PEB processes are a primary driver of acid catalyzed resists, the develop mode is shown in this work to have an overwhelming impact on the wafer to wafer and across wafer CD performance of these i-line processes. These changes have been able to improve the wafer to wafer CD distribution by more than 80 %, and the within wafer CD distribution by more than 50 % while enabling a greater than 50 % increase in lithography cluster throughput. The paper will discuss the contribution from each of the sources of variance and their importance in overall system performance.

Building Technological Capabilities in Ghanaian SMEs through Private Sector Development Programmes

DEFF Research Database (Denmark)

Kragelund, Jens Peter

2005-01-01

Since the beginning of the 1990s an increasing number of donors have initiated pro-grammes to support the private sector in developing countries in order to enhance eco-nomic growth and thereby alleviate poverty. This paper uses case studies of a wide spec-trum of private enterprises in Ghana...... and related business entities to illustrate how the private sector programme of Danida has worked in Ghana. It looks into the direct effects of the programme, i.e. capability building and simultaneously shows how conventional evaluation procedures miss many of the derived effects of the programme....

Enhancement of EAST plasma control capabilities

Energy Technology Data Exchange (ETDEWEB)

Xiao, Bingjia, E-mail: bjxiao@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei (China); Yuan, Qiping; Luo, Zhengping; Huang, Yao; Liu, Lei; Guo, Yong; Pei, Xiaofang; Chen, Shuliang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Humphreys, D.A.; Hyatt, A.W. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Mueller, Dennis [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Calabró, G.; Crisanti, F. [ENEA UnitàTecnicaFusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma (Italy); Albanese, R.; Ambrosino, R. [CREATE, Università di Napoli Federicao II, Università di Cassino and Università di Napoli Parthenope, Via Claudio 19, 80125 Napoli (Italy)

2016-11-15

Highlights: • Parallel plasma equilibrium reconstruction using GPU for real-time control on EAST. • Vertical control using Bang-bang + PID method to improve the response and minimize the oscillation caused by the latency. • Quasi-snow flake divertor plasma configuration has been demonstrated on EAST. - Abstract: In order to improve the plasma control performance and enhance the capability for advanced plasma control, new algorithms such as PEFIT/ISOFLUX plasma shape feedback control, quasi-snowflake plasma shape development and vertical control under new vertical control power supply, have been implemented and experimentally tested and verified in EAST 2014 campaign. P-EFIT is a rewritten version of EFIT aiming at fast real-time equilibrium reconstruction by using GPU for parallelized computation. Successful control using PEFIT/ISOFLUX was established in dedicated experiment. Snowfldivertor plasma shape has the advantage of spreading heat over the divertor target and a quasi-snowflake (QSF) configuration was achieved in discharges with I{sub p} = 0.25 MA and B{sub t} = 1.8T, κ∼1.9, by plasma position feedback control. The shape feedback control to achieve QSF shape has been preliminary implemented by using PEFIT and the initial experimental test has been done. For more robust vertical instability control, the inner coil (IC) and its power supply have been upgraded. A new control algorithm with the combination of Bang-bang and PID controllers has been developed. It is shown that new vertical control power supply together with the new control algorithms results in higher vertical controllability.

Undoing Quantitative Easing: Janet Yellen's Tiger Ride

Science.gov (United States)

Niederjohn, M. Scott; Schug, Mark C.; Wood, William C.

2014-01-01

"One who rides a tiger is afraid to dismount," says a colorful proverb from an earlier time. This may be an apt saying for the situation facing the new head of the Federal Reserve, Janet L. Yellen, who takes over at a time when successive rounds of Fed policy have taken the central bank into uncharted territory. By historical standards,…

Park-and-Ride motivations and air quality norms in Europe

NARCIS (Netherlands)

Dijk, Marc; de Haes, Jan; Montalvo, Carlos

2013-01-01

Transport congestion and the quality of the air in cities is a persistent concern for urban planners, and in this context Park and Ride (P. +. R) facilities have been proposed as an element of urban sustainability strategies in many cities in Europe. In 2008 a European Commission directive aimed at

Therapeutic riding followed by rhythmic auditory stimulation to improve balance and gait in a subject with orthopedic pathologies.

Science.gov (United States)

Ungermann, Cathryn M; Gras, Laura Z

2011-12-01

The study objectives were to investigate the effect of therapeutic riding with a subject who had an orthopedic diagnosis. This is a single-subject case report. The study was conducted at an equestrian facility with an indoor riding arena. The subject was a 59-year-old woman with grade I spondylolisthesis at L4/L5 and multilevel lumbar spinal stenosis in central and foraminal canals. The subject had an anterior cervical fusion of C3-C7. The subject has been ambulating with a straight cane due to her history of frequent falls. Gait, agility, strength, range of motion, and balance testing were performed. The subject had impairments of bilateral lower extremities with an ataxic gait pattern and was at risk for continued falls according to the balance measures. The intervention comprised therapeutic riding sessions 3 times a week for 20 minutes for 4 weeks. Each riding session was immediately followed by a 10-minute independent walking program with a metronome for rhythmic auditory stimulation. The outcome measures were as follows: Manual muscle testing and range of motion of the lower extremities, Gait Speed Test, Dynamic Gait Index, Four-Square Step Test, Chair Stand Test, Single Leg Stance. Improvements were seen in lower extremity strength and range of motion and balance. The subject improved on balance scores, placing her out of the risk for falls category. Therapeutic riding followed by rhythmic auditory stimulation improved lower extremity range of motion, strength, and balance with this subject.

Development of students learning capabilities and professional capabilities

DEFF Research Database (Denmark)

Ringtved, Ulla Lunde; Wahl, Christian; Belle, Gianna

This paper describes the work-in-progress on a project that aims todevelop a tool that via learning analytic methods enable studentsto enhance, document and assess the development of their learningcapabilities and professional capabilities in consequence of theirself-initiated study activities...... during their bachelor educations. Thetool aims at enhancing the development of students’ capabilities toself-initiate, self-regulate and self-assess their study activities.The tool uses the concept of collective intelligence as source formotivation and inspiration in self-initiating study activities...... as wellas self-assessing them. The tool is based on a heutagogical approachto support reflection on learning potential in these activities. Thisenhances the educational use of students self-initiated learningactivities by bringing visibility and evidence to them, and therebybringing value to the assessment...

Watching Your Back While Riding Your Bike

DEFF Research Database (Denmark)

Sokoler, Tomas; Bagalkot, Naveen

2017-01-01

series of investigations looking into the broader notion of integrating measures for preventive self-care with existing everyday activities (e.g daily motorcycle commute) by means of digital technology. We are guided by the concept of embodied self-monitoring grounded in theories on the embodied...... for interaction design in the domain of preventive self-care. We report on the outcome of in-situ enactments performed by four motorbike riders as co-explorers engaging with our interactive soft&hardware sketches while actually riding in traffic. Insitu enactments and follow-up interviews with the riders...

Kuhu kadus pensionäride kogutud 25 000 allkirja? / Jaanus Kõrv

Index Scriptorium Estoniae

Kõrv, Jaanus

2005-01-01

2003. aasta novembri alguses andsid Eesti Pensionäride Ühenduse esindajad ajalehe Videvik kaasabil üle Riigikogu spiikrile Ene Ergmale pöördumise 25 000 protestiallkirjaga, milles nõuti inimväärset pensioni. Valitsus pole pöördumisele reageerinud

Taurine protects DNA of lymphocytes against oxidative alteration in riding horses

DEFF Research Database (Denmark)

Sokól, Janusz Leszek; Sawosz, Ewa; Niemiec, Tomasz

2009-01-01

The study aimed at evaluation the effect of dietary supplement of taurine on the oxidation-reduction status in riding horses, and especially on the extent of oxidative DNA degradation in lymphocytes. Ten Thoroughbred and half-bred geldings aged 6-13 years were classified according to breed...... and amount of work done into two groups - control (C, n=5) and experimental (E, n=5), the latter fed the diet with addition of 40 g taurine/horse/day. Blood samples were withdrawn from the horses' jugular vein before commencing the riding season and then after 30 days of working. In the blood some selected....... The addition of taurine to feed caused smaller oxidative stress, manifested by lower concentration of TBA-RS in plasma and of 8-oxo-dG in lymphocytes. The taurine lowered the lipid peroxidation intensity that occurred in horses due to the oxidative stress caused by physical effort. Furthermore, taurine...

Optimization of Vehicle Suspension Parameters for Ride Comfort Based on RSM

Science.gov (United States)

Mitra, A. C.; Patil, M. V.; Banerjee, N.

2015-04-01

Vehicle suspension design requires an investigation to determine the spring and damper settings that assure optimal ride comfort (RC) of vehicle. In the present work response surface methodology (RSM), one of the methods of design of experiment has been successfully implemented for the purpose of finding optimal setting. Design of experiment sometimes requires accurate representation of the independent variables which are usually difficult to measure or else unavailable for experimentation. This paper proposes a simulation model to analyze the ride comfort with accurate independent variables as per Box-Behnken design of RSM. A prediction model of response variable, RC is developed using regression analysis which leads to a good agreement with simulated model ( R 2 = 99.74 %). The fitted model can be effectively used to evaluate optimal setting of spring stiffness and damping coefficient with the help of response optimization of a high desirability value.

Roller-coaster Ride to, Relief From TMJ | NIH MedlinePlus the Magazine

Science.gov (United States)

... on a roller coaster ride, seeking relief from temporomandibular joint (TMJ) disorder, which causes pain and, sometimes, dysfunction in the jaw joint and muscles of the neck, head, and face. She has endured: excruciating pain ...

Union Free-Riding in Britain and New Zealand

OpenAIRE

Alex Bryson

2006-01-01

The percentage of workers who choose not to join the union available to them at their workplace has been rising in Britain and New Zealand. Social custom, union instrumentality, the fixed costs of joining, employee perceptions of management attitudes to unionization and employee problems at work all influence the propensity to free-ride. Ideological convictions regarding the role of unions also play some role, as do private excludable goods. There is little indication of employer-inspired pol...

Investments by NASA to build planetary protection capability

Science.gov (United States)

Buxbaum, Karen; Conley, Catharine; Lin, Ying; Hayati, Samad

NASA continues to invest in capabilities that will enable or enhance planetary protection planning and implementation for future missions. These investments are critical to the Mars Exploration Program and will be increasingly important as missions are planned for exploration of the outer planets and their icy moons. Since the last COSPAR Congress, there has been an opportunity to respond to the advice of NRC-PREVCOM and the analysis of the MEPAG Special Regions Science Analysis Group. This stimulated research into such things as expanded bioburden reduction options, modern molecular assays and genetic inventory capability, and approaches to understand or avoid recontamination of spacecraft parts and samples. Within NASA, a portfolio of PP research efforts has been supported through the NASA Office of Planetary Protection, the Mars Technology Program, and the Mars Program Office. The investment strategy focuses on technology investments designed to enable future missions and reduce their costs. In this presentation we will provide an update on research and development supported by NASA to enhance planetary protection capability. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

Cyclist's nodule: no smooth ride.

Science.gov (United States)

Stoneham, Adam; Thway, Khin; Messiou, Christina; Smith, Myles

2016-03-10

A fit and active amateur cyclist was referred by his general practitioner to a surgical oncology outpatient clinic with a slowly-growing perineal mass. Following clinical examination, the patient underwent imaging and biopsy at a tertiary soft tissue tumour centre, which diagnosed perineal nodular induration: a rare, benign tumour caused by repetitive trauma associated with 'saddle sports' such as cycling or horse riding. It is important to consider soft tissue tumours in patients who present with 'lumps and bumps'; they can occur anywhere in the body including the groin or perineum, where it is sometimes referred to as a 'third' or 'accessory' testicle in men. Although unusual, the case emphasises the importance of rapid specialist referral from primary care, and consideration of a patient's occupation and hobbies when formulating diagnoses. 2016 BMJ Publishing Group Ltd.

Non conventional psychiatric rehabilitation in schizophrenia using therapeutic riding: the FISE multicentre Pindar project

Directory of Open Access Journals (Sweden)

Stefania Cerino

2011-12-01

Full Text Available The FISE (Federazione Italiana Sport Equestri Pindar is a multicentre research project aimed at testing the potential effects of therapeutic riding on schizophrenic patients. Twenty-four subjects with a diagnosis of schizophrenia were enrolled for a 1 year-treatment involving therapeutic riding sessions. All subjects were tested at the beginning and at the end of treatment with a series of validated test batteries (BPRS and 8 items-PANSS. The results discussed in this paper point out an improvement in negative symptoms, a constant disease remission in both early onset and chronic disease subjects, as well as a reduced rate of hospitalization.

Effects of Indoor Horseback Riding and Virtual Reality Exercises on the Dynamic Balance Ability of Normal Healthy Adults

Science.gov (United States)

Lee, Daehee; Lee, Sangyong; Park, Jungseo

2014-01-01

[Purpose] The objective of this study was to determine the effect of indoor horseback riding and virtual reality exercises on the dynamic balance ability of normal adults. [Subjects] This study enrolled 24 normal adults and divided them into two groups: an indoor horseback riding exercise group (IHREG, n = 12) and a virtual reality exercise group (VREG, n = 12). [Methods] IHREG exercised on indoor horseback riding equipment and VREG exercised using the Nintendo Wii Fit three times a week for six weeks. The Biodex Balance System was used to analyze dynamic balance as measured by the overall stability index (OSI), anteroposterior stability index (APSI), and mediolateral stability index (MLSI). [Results] In the within-group comparison, IHREG and VERG both showed significant decreases in the dynamic balance indexes of OSI, APSI, and MLSI after the intervention, but no significant difference was found between the groups. [Conclusion] Both indoor horseback riding and virtual reality exercises were effective at improving the subjects’ dynamic balance ability as measured by OSI, APSI, and MLSI, and can be used as additional exercises for patients with conditions affecting postural control. PMID:25540494

Prevalence of 'high-riding' superior pericardial recesses on thin-section 16-MDCT scans

Energy Technology Data Exchange (ETDEWEB)

Basile, Antonio [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy)]. E-mail: antodoc@yahoo.com; Bisceglie, Paola [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy); Giulietti, Giorgio [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy); Calcara, Giacomo [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy); Figuera, Michele [Department of Radiology, Ospedale Vittorio Emanuele, Via Plebiscito 628, 95124 Catania (Italy); Mundo, Elena [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy); Granata, Antonio [Department of Nephrology, Ospedale Vittorio Emanuele, Via Plebiscito 628, 95124 Catania (Italy); Runza, Giuseppe [Department of Radiology, Policlinico Universitario, Via del Vespro 129, 90127 Palermo (Italy); Privitera, Carmelo [Department of Radiology, Ospedale Vittorio Emanuele, Via Plebiscito 628, 95124 Catania (Italy); Privitera, Giambattista [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy); Patti, Maria Teresa [Department of Radiology and Interventional Radiology, Ospedale Ferrarotto, via Citelli, 8 95124 Catania (Italy)

2006-08-15

Objective: The aim of this study was to evaluate the prevalence of 'high-riding' superior pericardial recess (HRSPR) on thin-section (1 mm) 16-multidetector computed tomography (MDCT) scans. Materials and methods: Three hundred and fourteen consecutive chest CT scans obtained with a thin-section 16 MDCT were retrospectively evaluated. The prevalence and characteristic of HRSPR were analyzed. Results: HRSPR was depicted in 21 patients (11 men and 10 women) (6.6%) who ranged in age from 28 to 72 years (mean age, 57 years). The extended recesses were rounded/oval shaped in five patients and triangular, spindle, half moon or irregular shaped in the other 16 patients. Conclusion: Our data suggest as HRSPRs are more frequently and better depicted on thinsection MDCT scans, and this improves the capability to distinguish this superior extension of the superior aortic recess from abnormal findings such as lymphadenopathy, cystic lesions, and aortic dissection.

Predictive routing for autonomous mobility-on-demand systems with ride-sharing

NARCIS (Netherlands)

Alonso Mora, J.; Wallar, Alex; Rus, Daniela; Bicchi, A.; Maciejewski, T.

2017-01-01

Ride-sharing, or carpooling, systems with autonomous vehicles will provide efficient and reliable urban mobility on demand. In this work we present a method for dynamic vehicle routing that leverages historical data to improve the performance of a network of self-driving taxis. In particular, we

Traveler Preference for Park-and-Ride Facilities: Empirical Evidence of Generalizability

NARCIS (Netherlands)

Bos, D.M.; Heijden, R.E.C.M. van der; Molin, E.; Timmermans, H.

2005-01-01

This paper reports the main findings of a study, conducted in the Netherlands, aimed at testing whether preference functions for park-and-ride facilities, estimated from data collected in a specific Dutch region, can be generalized to a nationwide sample. Preference data in both samples were

Adaptive Planning: Understanding Organizational Workload to Capability/ Capacity through Modeling and Simulation

Science.gov (United States)

Hase, Chris

2010-01-01

In August 2003, the Secretary of Defense (SECDEF) established the Adaptive Planning (AP) initiative [1] with an objective of reducing the time necessary to develop and revise Combatant Commander (COCOM) contingency plans and increase SECDEF plan visibility. In addition to reducing the traditional plan development timeline from twenty-four months to less than twelve months (with a goal of six months)[2], AP increased plan visibility to Department of Defense (DoD) leadership through In-Progress Reviews (IPRs). The IPR process, as well as the increased number of campaign and contingency plans COCOMs had to develop, increased the workload while the number of planners remained fixed. Several efforts from collaborative planning tools to streamlined processes were initiated to compensate for the increased workload enabling COCOMS to better meet shorter planning timelines. This paper examines the Joint Strategic Capabilities Plan (JSCP) directed contingency planning and staffing requirements assigned to a combatant commander staff through the lens of modeling and simulation. The dynamics of developing a COCOM plan are captured with an ExtendSim [3] simulation. The resulting analysis provides a quantifiable means by which to measure a combatant commander staffs workload associated with development and staffing JSCP [4] directed contingency plans with COCOM capability/capacity. Modeling and simulation bring significant opportunities in measuring the sensitivity of key variables in the assessment of workload to capability/capacity analysis. Gaining an understanding of the relationship between plan complexity, number of plans, planning processes, and number of planners with time required for plan development provides valuable information to DoD leadership. Through modeling and simulation AP leadership can gain greater insight in making key decisions on knowing where to best allocate scarce resources in an effort to meet DoD planning objectives.

A comparison of optimal semi-active suspension systems regarding vehicle ride comfort

Science.gov (United States)

Koulocheris, Dimitrios; Papaioannou, Georgios; Chrysos, Emmanouil

2017-10-01

The aim of this work is to present a comparison of the main semi active suspension systems used in a passenger car, after having optimized the suspension systems of the vehicle model in respect with ride comfort and road holding. Thus, a half car model, equipped with controllable dampers, along with a seat and a driver was implemented. Semi-active suspensions have received a lot of attention since they seem to provide the best compromise between cost (energy consumption, actuators/sensors hardware) and performance in comparison with active and passive suspensions. In this work, the semi active suspension systems studied are comfort oriented and consist of (a) the two version of Skyhook control (two states skyhook and skyhook linear approximation damper), (b) the acceleration driven damper (ADD), (c) the power driven damper (PDD), (d) the combination of Skyhook and ADD (Mixed Skyhook-ADD) and (e) the combination of the two with the use of a sensor. The half car model equipped with the above suspension systems was excited by a road bump, and was optimized using genetic algorithms (GA) in respect with ride comfort and road holding. This study aims to highlight how the optimization of the vehicle model could lead to the best compromise between ride comfort and road holding, overcoming their well-known trade-off. The optimum results were compared with important performance metrics regarding the vehicle’s dynamic behaviour in general.

Solving the Dial-a-Ride Problem using Genetic algorithms

DEFF Research Database (Denmark)

Bergvinsdottir, Kristin Berg; Larsen, Jesper; Jørgensen, Rene Munk

In the Dial-a-Ride problem (DARP) customers send transportation requests to an operator. A request consists of a specified pickup location and destination location along with a desired departure or arrival time and demand. The aim of DARP is to minimize transportation cost while satisfying custom...... routing problems for the vehicles using a routing heuristic. The algorithm is implemented in Java and tested on publicly available data sets....

Interaction of Leptospira interrogans with Human Proteolytic Systems Enhances Dissemination through Endothelial Cells and Protease Levels

Science.gov (United States)

Vieira, Monica L.; Alvarez-Flores, Miryam P.; Kirchgatter, Karin; Romero, Eliete C.; Alves, Ivy J.; de Morais, Zenaide M.; Vasconcellos, Silvio A.; Chudzinski-Tavassi, Ana M.

2013-01-01

We have recently reported the ability of Leptospira to capture plasminogen (PLG) and generate plasmin (PLA) bound on the microbial surface in the presence of exogenous activators. In this work, we examined the effects of leptospiral PLG binding for active penetration through the endothelial cell barrier and activation. The results indicate that leptospires with PLG association or PLA activation have enhanced migration activity through human umbilical vein endothelial cell (HUVEC) monolayers compared with untreated bacteria. Leptospira cells coated with PLG were capable of stimulating the expression of PLG activators by HUVECs. Moreover, leptospires endowed with PLG or PLA promoted transcriptional upregulation matrix metalloprotease 9 (MMP-9). Serum samples from patients with confirmed leptospirosis showed higher levels of PLG activators and total MMP-9 than serum samples from normal (healthy) subjects. The highest level of PLG activators and total MMP-9 was detected with microscopic agglutination test (MAT)-negative serum samples, suggesting that this proteolytic activity stimulation occurs at the early stage of the disease. Furthermore, a gelatin zymography profile obtained for MMPs with serum samples from patients with leptospirosis appears to be specific to leptospiral infection because serum samples from patients with unrelated infectious diseases produced no similar degradation bands. Altogether, the data suggest that the Leptospira-associated PLG or PLA might represent a mechanism that contributes to bacterial penetration of endothelial cells through an activation cascade of events that enhances the proteolytic capability of the organism. To our knowledge, this is the first proteolytic activity associated with leptospiral pathogenesis described to date. PMID:23478319

Available transfer capability evaluation and enhancement using various FACTS controllers: Special focus on system security

Directory of Open Access Journals (Sweden)

M. Venkateswara Rao

2016-03-01

Full Text Available Nowadays, because of the deregulation of the power industry the continuous increase of the load increases the necessity of calculation of available transfer capability (ATC of a system to analyze the system security. With this calculation, the scheduling of generator can be decided to decrease the system severity. Further, constructing new transmission lines, new substations are very cost effective to meet the increasing load and to increase the transfer capability. Hence, an alternative way to increase the transfer capability is use of flexible ac transmission system (FACTS controllers. In this paper, SSSC, STACOM and UPFC are considered to show the effect of these controllers in enhancing system ATC. For this, a novel current based modeling and optimal location strategy of these controllers are presented. The proposed methodology is tested on standard IEEE-30 bus and IEEE-57 bus test systems with supporting numerical and graphical results.

Are all-terrain vehicle riders willing to pay trail user fees to ride on public lands in the USA?

Science.gov (United States)

Stephanie A. Snyder; Robert A. Smail

2009-01-01

Some public lands in the USA offer opportunities for all-terrain vehicle (ATV) riding, but few charge trail use fees. In a case study in the US state of Wisconsin, the contingent valuation method was used to examine riders' willingness to pay (WTP) to ride on public lands. Information on riders' habits, preferences and responses to a dichotomous choice WTP...

Alliance capability as a mediator between experience and alliance performance

DEFF Research Database (Denmark)

Heimeriks, Koen; Duysters, Geert

This study centers around the way in which firms can enhance alliance performance through the development of alliance capabilities. Whereas most research has focused on inter-firm antecedents of alliance performance, research on intra-firm antecedents pointing to prior experience and internal...... alliance managers and Vice-Presidents of 151 firms. The survey covers over 2600 alliances for the period 1997-2001. This study not only finds that alliance capabilities partially mediate between alliance experience and alliance performance, but also yields novel insights into the micro-level building...

Gust Wind Effects on Stability and Ride Quality of Actively Controlled Maglev Guideway Systems

Directory of Open Access Journals (Sweden)

Dong-Ju Min

2017-01-01

Full Text Available The purpose of this paper is to present a framework to analyze the interaction between an actively controlled magnetic levitation vehicle and a guideway structure under gusty wind. The equation of motion is presented for a 30-dof maglev vehicle model consisting of one cabin and four bogies. In addition, a lateral electromagnetic suspension (EMS system is introduced to improve the running safety and ride quality of the maglev vehicle subjected to turbulent crosswind. By using the developed simulation tools, the effects of various parameters on the dynamic response of the vehicle and guideway are investigated in the case of the UTM maglev vehicle running on a simply supported guideway and cable-stayed guideway. The simulation results show that the independent lateral EMS and associated control scheme are definitely helpful in improving the running safety and ride quality of the vehicle under gusty wind. In the case of the cable-stayed guideway, at low wind speed, vehicle speed is the dominant factor influencing the dynamic responses of the maglev vehicle and the guideway, but at wind speed over 10 m/s, wind becomes the dominant factor. For the ride quality of the maglev vehicle, wind is also the most influential factor.

Time-over-threshold readout to enhance the high flux capabilities of single-photon-counting detectors

International Nuclear Information System (INIS)

Bergamaschi, Anna; Dinapoli, Roberto; Greiffenberg, Dominic; Henrich, Beat; Johnson, Ian; Mozzanica, Aldo; Radicci, Valeria; Schmitt, Bernd; Shi, Xintian; Stoppani, Laura

2011-01-01

The MYTHEN photon-counting ASIC operated in time-over-threshold mode shows an innovative approach towards the development of a detector operating with very high photon intensities while maintaining the single-photon sensitivity for synchrotron radiation experiments. The MYTHEN single-photon-counting (SPC) detector has been characterized using the time-over-threshold (ToT) readout method, i.e. measuring the time that the signal produced by the detected X-rays remains above the comparator threshold. In the following it is shown that the ToT readout preserves the sensitivity, dynamic range and capability of background suppression of the SPC mode, while enhancing the count-rate capability, which is the main limitation of state-of-the-art SPC systems

Time-over-threshold readout to enhance the high flux capabilities of single-photon-counting detectors

Energy Technology Data Exchange (ETDEWEB)

Bergamaschi, Anna, E-mail: anna.bergamaschi@psi.ch; Dinapoli, Roberto; Greiffenberg, Dominic; Henrich, Beat; Johnson, Ian; Mozzanica, Aldo; Radicci, Valeria; Schmitt, Bernd; Shi, Xintian; Stoppani, Laura [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

2011-11-01

The MYTHEN photon-counting ASIC operated in time-over-threshold mode shows an innovative approach towards the development of a detector operating with very high photon intensities while maintaining the single-photon sensitivity for synchrotron radiation experiments. The MYTHEN single-photon-counting (SPC) detector has been characterized using the time-over-threshold (ToT) readout method, i.e. measuring the time that the signal produced by the detected X-rays remains above the comparator threshold. In the following it is shown that the ToT readout preserves the sensitivity, dynamic range and capability of background suppression of the SPC mode, while enhancing the count-rate capability, which is the main limitation of state-of-the-art SPC systems.

Improvement of Ride Quality of Railway Vehicle by Semiactive Secondary Suspension System on Roller Rig Using Magnetorheological Damper

Directory of Open Access Journals (Sweden)

Yu-Jeong Shin

2014-07-01

Full Text Available Ride quality became a very important factor in the performance of railway vehicles according to the expansion of high-speed railways and speedup of velocity of railway vehicles. In this study, the results of applying the MR (magnetorheological lateral damper on the secondary suspension to reduce the vibration of the car body, directly relating to the ride quality of railway vehicles, were mentioned. In order to verify the control performance of MR dampers, a 1/5 scaled railway vehicle model was constructed, and numerical simulation and experimental tests were conducted. The MR damper for the experimental tests was produced and was attached between the car body and bogie of a full scaled vehicle, and a vibration controlling test was performed to improve ride quality on a roller rig. The skyhook control algorithm was used as the controlling technique, and regarding the test results, the RMS (root mean square value was found by compensating the frequency of the lateral vibration based on the UIC 513 R Standard about the ride quality of railway vehicles. As a result of the test, it could be confirmed that vibration was reduced by approximately 24% when attaching the MR damper between the bogie and the car body compared to when applying a passive damper.

The effect of cannabis on regular cannabis consumers' ability to ride a bicycle.

Science.gov (United States)

Hartung, Benno; Schwender, Holger; Roth, Eckhard H; Hellen, Florence; Mindiashvili, Nona; Rickert, Annette; Ritz-Timme, Stefanie; Grieser, Almut; Monticelli, Fabio; Daldrup, Thomas

2016-05-01

To assess the effects of cannabis on the ability required to ride a bicycle, repetitive practical cycling tests and medical examinations were carried out before and after inhalative consumption of cannabis. A maximum of three joints with body weight-adapted THC content (300 μg THC per kg body weight) could be consumed by each test subject. Fourteen regular cannabis-consuming test subjects were studied (12 males, 2 females). In summary, only a few driving faults were observed even under the influence of very high THC concentrations. A defined THC concentration that leads to an inability to ride a bicycle cannot be presented. The test subjects showed only slight distinctive features that can be documented using a medical test routinely run for persons under suspicion of driving under the influence of alcohol or drugs.

Re-framing Inclusive Education Through the Capability Approach: An Elaboration of the Model of Relational Inclusion

Directory of Open Access Journals (Sweden)

Maryam Dalkilic

2016-09-01

Full Text Available Scholars have called for the articulation of new frameworks in special education that are responsive to culture and context and that address the limitations of medical and social models of disability. In this article, we advance a theoretical and practical framework for inclusive education based on the integration of a model of relational inclusion with Amartya Sen’s (1985 Capability Approach. This integrated framework engages children, educators, and families in principled practices that acknowledge differences, rather than deficits, and enable attention to enhancing the capabilities of children with disabilities in inclusive educational environments. Implications include the development of policy that clarifies the process required to negotiate capabilities and valued functionings and the types of resources required to permit children, educators, and families to create relationally inclusive environments.

The effect of therapeutic horseback riding on balance in community-dwelling older adults: a pilot study.

Science.gov (United States)

Homnick, Tamara D; Henning, Kim M; Swain, Charlene V; Homnick, Douglas N

2015-02-01

Equine assisted activities (hippotherapy and therapeutic riding) improve balance in patients with disabilities such as cerebral palsy, but have not been systematically studied in older adults, at risk of falls due to balance deficits. We conducted a 10-week, single blind, controlled trial of the effect of a therapeutic horseback riding course on measures of balance in community-dwelling adults 65 years and older. Nine riders and six controls completed the trial. Controls were age matched to riders and all participants were recruited from the local community. Both groups showed improvements in balance during the trial, but did not reach statistical significance. Sample size was small, participants had relatively high initial balance scores, and controls tended to increase their physical activities, likely influencing outcomes. No adverse events occurred and the supervised therapeutic riding program appeared to be a safe and effective form of exercise to improve balance in older adults. A power analysis was performed to estimate numbers of participants needed for a larger study. © The Author(s) 2012.

Building capability through networking with investors and researchers

DEFF Research Database (Denmark)

Wang, Daojuan; Schøtt, Thomas

A startup requires financing, typically, and the startup is based on innovation, often. Capabilities for innovation and financing may be built simultaneously and created jointly at inception. Co-creation of capabilities for financing and innovation is accounted for in this study. Co...

Enhancing radiation biodosimetry capability

International Nuclear Information System (INIS)

Alok, A.; Kumar, A.; Kulshrestra, S.; Choudhary, S.; Bhagi, S.; Adhikari, J.S.; Chaudhury, N.K.

2016-01-01

Biodosimetry laboratories are necessary for quick and accurate assessment of absorbed radiation dose in suspected individuals for their medical management. The method is based on dicentric chromosomal assay (Gold standard). This assay is completely manual and time consuming, require skill and competency of laboratory staff. There is a necessity of more biodosimetry labs within country and networking within and at international level for enhancing medical preparedness for management of radiation emergency

Extension of ERIM multispectral data processing capabilities through improved data handling techniques

Science.gov (United States)

Kriegler, F. J.

1973-01-01

The improvement and extension of the capabilities of the Environmental Research Institute of Michigan processing facility in handling multispectral data are discussed. Improvements consisted of implementing hardware modifications which permitted more rapid access to the recorded data through improved numbering and indexing of such data. In addition, techniques are discussed for handling data from sources other than the ERIM M-5 and M-7 scanner systems.

Enhanced Flexibility and Reusability through State Machine-Based Architectures for Multisensor Intelligent Robotics

Directory of Open Access Journals (Sweden)

Héctor Herrero

2017-05-01

Full Text Available This paper presents a state machine-based architecture, which enhances the flexibility and reusability of industrial robots, more concretely dual-arm multisensor robots. The proposed architecture, in addition to allowing absolute control of the execution, eases the programming of new applications by increasing the reusability of the developed modules. Through an easy-to-use graphical user interface, operators are able to create, modify, reuse and maintain industrial processes, increasing the flexibility of the cell. Moreover, the proposed approach is applied in a real use case in order to demonstrate its capabilities and feasibility in industrial environments. A comparative analysis is presented for evaluating the presented approach versus traditional robot programming techniques.

Aging effect on plasma metabolites and hormones concentrations in riding horses

Directory of Open Access Journals (Sweden)

K. Kawasumi

2015-11-01

Full Text Available Age effects on plasma metabolites, hormone concentrations, and enzyme activities related to energy metabolism were investigated in 20 riding horses. Animals were divided into two groups: Young (3-8 years and aged (11-18 years. They were clinically healthy, and not obese. Plasma adiponectin (ADN concentrations in aged horses were significantly lower than those in young horses (mean±SE, 6.5±1.3 μg mL-1 vs, 10.9±1.7 μg mL-1, Mann-Whitney U test, respectively; P=0.0233. Plasma non-esterified fatty acid levels and Insulin and malondialdehyde concentrations in aged group tended to increase compared to those in young group although there were not significant differences statistically. In aged group, malate dehydrogenase/lactate dehydrogenase (M/L ratio, which is considered an energy metabolic indicator, did not change significantly compared to that in young group. Present data suggest that aging may negatively affect nutrition metabolism, but not induce remarkable changes in M/L ratio in riding horses.

Improving environmental performance through unit-level organizational citizenship behaviors for the environment: A capability perspective.

Science.gov (United States)

Alt, Elisa; Spitzeck, Heiko

2016-11-01

Organizational citizenship behaviors for the environment (OCBEs) are increasingly advocated as a means of complementing formal practices in improving environmental performance. Adopting a capability perspective, we propose that a firm's employee involvement capability translates into environmental performance through the manifestation of unit-level OCBEs, and that this relationship is amplified by a shared vision capability. In a cross-country and multi-industry sample of 170 firms, we find support for our hypotheses, shedding light on contextual determinants of OCBEs, and on how firms may engender a positive relationship between top-down environmental initiatives and bottom-up behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ride Your Luck! A Field Experiment on Lottery-Based Incentives for Compliance

NARCIS (Netherlands)

M. Fabbri (Marco); P.N. Barbieri (Paolo); M. Bigoni (Maria)

2016-01-01

textabstractWe designed a natural-field experiment in the context of local public transportation to test whether rewards in the form of lottery prizes coupled with traditional sanctions efficiently reduce free-riding. We organized a lottery in a medium-size Italian city the participation in which is

Cognition and relative importance underlying consumer valuation of park-and-ride facilities

NARCIS (Netherlands)

Bos, D.M.; Molin, E.J.E.; Timmermans, H.J.P.; vd Heijden, R.E.C.M.

2003-01-01

Results are reported of a study designed to identify the cognitive constructs underlying the valuation of park-and-ride (P&R) facilities and to measure the relative importance attached to the attributes of such facilities. Results show that the reliability of public transport is quite important.

Implementing Firm Dynamic Capabilities Through the Concept Design Process

DEFF Research Database (Denmark)

Nedergaard, Nicky; Jones, Richard

2011-01-01

It is well understood that firms operating in highly dynamic and fluid markets need to possess strong dynamic capabilities of sensing (market trajectories), seizing (to capitalise on these trajectories), and transformation (in order to implement sustainable strategies). Less understood is how firms...... actually implement these capabilities. A conceptual model showing how managing concept design processes can help firms systematically develop dynamic capabilities and help bridge the gap between the market-oriented and resource-focused strategic perspectives is presented. By placing this model in a design......-driven innovation perspective three theoretical propositions is derived explicating both the paper’s implementation approach to dynamic capabilities as well as new ways of understanding these capabilities. Concluding remarks are made discussing both the paper’s contribution to the strategic marketing literature...

Capability Development in an Offshoring Context

DEFF Research Database (Denmark)

Jaura, Manya

Capability development can be defined as deliberate firm-level investment involving a search and learning process aimed at modifying or enhancing existing capabilities. Increasingly, firms are relocating advanced services to offshore locations resulting in the challenge of capability development ...

Enhancing Environmental Friendliness through Mobile Phone ...

African Journals Online (AJOL)

Enhancing Environmental Friendliness through Mobile Phone Learning. ... Journal Home > Vol 18, No 1 (2014) > ... Environmental friendly or eco-friendly refers to products or processes that are not harmful to the environment and people who ...

The high-riding superior aortic recess of the pericardium: MRI visualization in a child

International Nuclear Information System (INIS)

Cohen, Mervyn; Johnson, Tiffanie; Hoyer, Mark

2005-01-01

We report a 4-year-old child with a high-riding superior aortic recess of the pericardium, initially misdiagnosed as a possible vascular malformation. The anatomy of the pericardial recesses is reviewed. (orig.)

Developing a model-based decision support system for call-a-ride paratransit service problems.

Science.gov (United States)

2011-02-01

Paratransit is the transportation service that supplements larger public transportation : systems by providing individualized rides without fixed routes or timetables. In 1990, : the Americans with Disabilities Act (ADA) was passed which allows passe...

The new MCNP6 depletion capability

International Nuclear Information System (INIS)

Fensin, M. L.; James, M. R.; Hendricks, J. S.; Goorley, J. T.

2012-01-01

The first MCNP based in-line Monte Carlo depletion capability was officially released from the Radiation Safety Information and Computational Center as MCNPX 2.6.0. Both the MCNP5 and MCNPX codes have historically provided a successful combinatorial geometry based, continuous energy, Monte Carlo radiation transport solution for advanced reactor modeling and simulation. However, due to separate development pathways, useful simulation capabilities were dispersed between both codes and not unified in a single technology. MCNP6, the next evolution in the MCNP suite of codes, now combines the capability of both simulation tools, as well as providing new advanced technology, in a single radiation transport code. We describe here the new capabilities of the MCNP6 depletion code dating from the official RSICC release MCNPX 2.6.0, reported previously, to the now current state of MCNP6. NEA/OECD benchmark results are also reported. The MCNP6 depletion capability enhancements beyond MCNPX 2.6.0 reported here include: (1) new performance enhancing parallel architecture that implements both shared and distributed memory constructs; (2) enhanced memory management that maximizes calculation fidelity; and (3) improved burnup physics for better nuclide prediction. MCNP6 depletion enables complete, relatively easy-to-use depletion calculations in a single Monte Carlo code. The enhancements described here help provide a powerful capability as well as dictate a path forward for future development to improve the usefulness of the technology. (authors)

The New MCNP6 Depletion Capability

International Nuclear Information System (INIS)

Fensin, Michael Lorne; James, Michael R.; Hendricks, John S.; Goorley, John T.

2012-01-01

The first MCNP based inline Monte Carlo depletion capability was officially released from the Radiation Safety Information and Computational Center as MCNPX 2.6.0. Both the MCNP5 and MCNPX codes have historically provided a successful combinatorial geometry based, continuous energy, Monte Carlo radiation transport solution for advanced reactor modeling and simulation. However, due to separate development pathways, useful simulation capabilities were dispersed between both codes and not unified in a single technology. MCNP6, the next evolution in the MCNP suite of codes, now combines the capability of both simulation tools, as well as providing new advanced technology, in a single radiation transport code. We describe here the new capabilities of the MCNP6 depletion code dating from the official RSICC release MCNPX 2.6.0, reported previously, to the now current state of MCNP6. NEA/OECD benchmark results are also reported. The MCNP6 depletion capability enhancements beyond MCNPX 2.6.0 reported here include: (1) new performance enhancing parallel architecture that implements both shared and distributed memory constructs; (2) enhanced memory management that maximizes calculation fidelity; and (3) improved burnup physics for better nuclide prediction. MCNP6 depletion enables complete, relatively easy-to-use depletion calculations in a single Monte Carlo code. The enhancements described here help provide a powerful capability as well as dictate a path forward for future development to improve the usefulness of the technology.

Identifying the psychological determinants of risky riding: an application of an extended Theory of Planned Behaviour.

Science.gov (United States)

Chorlton, Kathryn; Conner, Mark; Jamson, Samantha

2012-11-01

The Theory of Planned Behaviour (TPB) plus moral norms, anticipated regret, past behaviour, self-identity and perceived susceptibility was applied to predicting motorcyclists' intention to ride above the speed limit and ride at inappropriate speeds. Past behaviour, control beliefs, attitudes, moral norm, normative beliefs, age and self-identity explained 60% of the variance in motorcyclists' intention to exceed the speed limit on motorways (N=1381). A total of 62% of the variance in motorcyclists' intention to really go for it on rural roads was accounted for, with past behaviour, attitudes, control beliefs, age, normative beliefs, anticipated regret, self-identity, behavioural beliefs and training status being significant (N=1116). Finally, attitudes, past behaviour, control beliefs, moral norm, anticipated regret, behavioural beliefs, normative beliefs, engine size and self-identity explained 57% of the variance in motorcyclists' intention to ride faster than felt safe in order to keep up with the group (N=1940). The belief-based measures also successfully differentiated between those who intended to speed and those who did not. Theoretical and practical implications of the findings are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Effects of Hippotherapy and a Horse Riding Simulator on the Balance of Children with Cerebral Palsy

Science.gov (United States)

Lee, Chae-Woo; Kim, Seong Gil; Na, Sang Su

2014-01-01

[Purpose] We with respect to their effects on the compared hippotherapy with a horseback riding simulator (JOBA, Panasonic Inc. JP) static and dynamic balance of children with cerebral palsy (CP). [Subjects and Methods] Twenty-six children were randomly divided into two groups: a hippotherapy group that included 13 children, and a horseback riding simulator (JOBA, Panasonic Inc., Japan) group, which was also composed of 13 children. The two groups participated in 1 hour of exercise per day, 3 times a week, for 12 weeks. The subjects’ static balance ability was measured using BPM (software 5.3, SMS Healthcare Inc., UK) as the center of pressure sway length while standing for 30 seconds with their eyes open and looking to the front. Dynamic balance ability was measured using the PBS (Pediatric Balance Scale). [Results] Both groups showed significant improvements in static and dynamic balance but significant differences between the two groups were not found. [Conclusion] The horseback riding simulator could be a useful alternative to hippotherapy for the improvement of static and dynamic balance of children with CP. PMID:24707098

Solvothermal preparation of micro/nanostructured TiO_2 with enhanced lithium storage capability

International Nuclear Information System (INIS)

Li, Jie; Wang, Chao; Zheng, Ping; Zhang, Lei; Chen, Gongxuan; Tang, Chengchun; Wu, Tian

2017-01-01

Facile and controllable preparation of TiO_2 is of prime importance to elaborately tailor and then fully exploit its intriguing functionalities in energy storage, catalysis and environmental remediation. Herein, a solvothermal method combined with post annealing is conducted, in which the hydrolysis of tetrabutyl titanate is controlled by the in-situ generated water during solvothermal treatment. By controlling synthetic conditions (i.e. reactant ratio, solvothermal temperature and reaction time), we manage to tailor the morphologies of TiO_2. Specially, three typical structures (nanoparticle, nanoneedle and nanorod) are studied to reveal the growth mechanism and the effects of the synthesis conditions. Nanoneedle-structured TiO_2 shows higher specific capacity and enhanced cycle stability as anode material for lithium ion batteries. - Highlights: • Controllable preparation of nano-TiO_2 is achieved by a solvothermal method. • TiO_2 morphology is tailored by tuning reactant ratio, temperature and duration. • Needle structured TiO_2 shows enhanced lithium storage capability.

FLC based adjustable speed drives for power quality enhancement

Directory of Open Access Journals (Sweden)

Sukumar Darly

2010-01-01

Full Text Available This study describes a new approach based on fuzzy algorithm to suppress the current harmonic contents in the output of an inverter. Inverter system using fuzzy controllers provide ride-through capability during voltage sags, reduces harmonics, improves power factor and high reliability, less electromagnetic interference noise, low common mode noise and extends output voltage range. A feasible test is implemented by building a model of three-phase impedance source inverter, which is designed and controlled on the basis of proposed considerations. It is verified from the practical point of view that these new approaches are more effective and acceptable to minimize the harmonic distortion and improves the quality of power. Due to the complex algorithm, their realization often calls for a compromise between cost and performance. The proposed optimizing strategies may be applied in variable-frequency dc-ac inverters, UPSs, and ac drives.

Solving the Dial-a-Ride Problem using Genetic Algorithms

DEFF Research Database (Denmark)

Jørgensen, Rene Munk; Larsen, Jesper; Bergvinsdottir, Kristin Berg

2007-01-01

In the Dial-a-Ride problem (DARP), customers request transportation from an operator. A request consists of a specified pickup location and destination location along with a desired departure or arrival time and capacity demand. The aim of DARP is to minimize transportation cost while satisfying ...... routing problems for the vehicles using a routing heuristic. The algorithm is implemented in Java and tested on publicly available data sets. The new solution method has achieved solutions comparable with the current state-of-the-art methods....

LVRT Capability of Single-Phase Grid-Connected HERIC Inverter in PV Systems by a Look-up Table Based Predictive Control

DEFF Research Database (Denmark)

Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

2017-01-01

Nowadays capacity of the photovoltaic systems in the grid is remarkable and provides a major part of energy in the grid. Therefore, an abruption of these systems from the grid can create a damage to the grid. Unlike in the past that PV systems disconnected from the grid when a voltage drop occurred......, nowadays these systems should have Low Voltage Ride-Through (LVRT) capability. The PV system should stay connected to the grid at fault time and help to recover the grid voltage by injecting the reactive power like in a power plant or a custom power device. There are two important factors for single phase...... grid connected PV inverters. The first one is the structure of the inverter and the second one is the control part. In this regard, the HERIC inverter can be a good selection among the transformerless inverters for a PV system due to its high efficiency. For the control part, this paper presents a look...

RIDES: Robust Intrusion Detection System for IP-Based Ubiquitous Sensor Networks.

Science.gov (United States)

Amin, Syed Obaid; Siddiqui, Muhammad Shoaib; Hong, Choong Seon; Lee, Sungwon

2009-01-01

The IP-based Ubiquitous Sensor Network (IP-USN) is an effort to build the "Internet of things". By utilizing IP for low power networks, we can benefit from existing well established tools and technologies of IP networks. Along with many other unresolved issues, securing IP-USN is of great concern for researchers so that future market satisfaction and demands can be met. Without proper security measures, both reactive and proactive, it is hard to envisage an IP-USN realm. In this paper we present a design of an IDS (Intrusion Detection System) called RIDES (Robust Intrusion DEtection System) for IP-USN. RIDES is a hybrid intrusion detection system, which incorporates both Signature and Anomaly based intrusion detection components. For signature based intrusion detection this paper only discusses the implementation of distributed pattern matching algorithm with the help of signature-code, a dynamically created attack-signature identifier. Other aspects, such as creation of rules are not discussed. On the other hand, for anomaly based detection we propose a scoring classifier based on the SPC (Statistical Process Control) technique called CUSUM charts. We also investigate the settings and their effects on the performance of related parameters for both of the components.

Enhancing electrical energy storage capability of dielectric polymer nanocomposites via the room temperature Coulomb blockade effect of ultra-small platinum nanoparticles.

Science.gov (United States)

Wang, Liwei; Huang, Xingyi; Zhu, Yingke; Jiang, Pingkai

2018-02-14

Introducing a high dielectric constant (high-k) nanofiller into a dielectric polymer is the most common way to achieve flexible nanocomposites for electrostatic energy storage devices. However, the significant decrease of breakdown strength and large increase of dielectric loss has long been known as the bottleneck restricting the enhancement of practical energy storage capability of the nanocomposites. In this study, by introducing ultra-small platinum (energy density of the Pt@PDA@BT nanocomposites is increased by nearly 70% because of the improved energy storage efficiency. This research provides a simple, promising and unique way to enhance energy storage capability of high-k polymer nanocomposites.

Executive Summary of Ares V: Lunar Capabilities Concept Review Through Phase A-Cycle 3

Science.gov (United States)

Holladay, J. B.; Baggett, K. E.; Feldman, S. M.

2011-01-01

This Technical Memorandum (TM) was generated as an overall Ares V summary from the Lunar Capabilities Concept Review (LCCR) through Phase A-Cycle 3 (PA-C3) with the intent that it may be coupled with separately published appendices for a more detailed, integrated narrative. The Ares V has evolved from the initial point of departure (POD) 51.00.48 LCCR configuration to the current candidate POD, PA-C3D, and the family of vehicles concept that contains vehicles PA-C3A through H. The logical progression from concept to POD vehicles is summarized in this TM and captures the trade space and performance of each. The family-of-vehicles concept was assessed during PA-C3 and offered flexibility in the path forward with the ability to add options deemed appropriate. A description of each trade space is given in addition to a summary of each Ares V element. The Ares V contributions to a Mars campaign are also highlighted with the goal of introducing Ares V capabilities within the trade space. The assessment of the Ares V vehicle as it pertains to Mars missions remained locked to the architecture presented in Mars Design Reference Authorization 5.0 using the PA-C3D vehicle configuration to assess Mars transfer vehicle options, in-space EDS capabilities, docking adaptor and propellant transfer assessments, and lunar and Mars synergistic potential.

Magneto-rheological suspensions for improving ground vehicle's ride comfort, stability, and handling

Science.gov (United States)

Ahmadian, Mehdi

2017-10-01

A state-of-the-art discussion on the applications of magneto-rheological (MR) suspensions for improving ride comfort, handling, and stability in ground vehicles is discussed for both road and rail applications. A historical perspective on the discovery and engineering development of MR fluids is presented, followed by some of the common methods for modelling their non-Newtonian behaviour. The common modes of the MR fluids are discussed, along with the application of the fluid in valve mode for ground vehicles' dampers (or shock absorbers). The applications span across nearly all road vehicles, including automobiles, trains, semi-trucks, motorcycles, and even bicycles. For each type of vehicle, the results of some of the past studies is presented briefly, with reference to the originating study. It is discussed that Past experimental and modelling studies have indicated that MR suspensions provide clear advantages for ground vehicles that far surpasses the performance of passive suspension. For rail vehicles, the primary advantage is in terms of increasing the speed at which the onset of hunting occurs, whereas for road vehicles - mainly automobiles - the performance improvements are in terms of a better balance between vehicle ride, handling, and stability. To further elaborate on this point, a single-suspension model is used to develop an index-based approach for studying the compromise that is offered by vehicle suspensions, using the H2 optimisation approach. Evaluating three indices based on the sprung-mass acceleration, suspension rattlespace, and tyre deflection, it is clearly demonstrated that MR suspensions significantly improve road vehicle's ride comfort, stability, and handling in comparison with passive suspensions. For rail vehicles, the simulation results indicate that using MR suspensions with an on-off switching control can increase the speed at which the on-set of hunting occurs by as much as 50% to more than 300%.

Induction generator model in phase coordinates for fault ride-through capability studies of wind turbines

DEFF Research Database (Denmark)

Fajardo, L.A.; Iov, F.; Medina, R.J.A.

2007-01-01

A phase coordinates induction generator model with time varying electrical parameters as influenced by magnetic saturation and rotor deep bar effects, is presented in this paper. The model exhibits a per-phase formulation, uses standard data sheet for characterization of the electrical parameters...... are conducted in a representative sized system and results show aptness of the proposed model over other two models. This approach is also constructive to support grid code requirements....

Managing Capabilities for Supply Chain Resilience Through it Integration

Directory of Open Access Journals (Sweden)

Gružauskas Valentas

2017-08-01

Full Text Available The trend for e-commerce, estimated population size to 11 billion by 2050, and an increase in urbanization level to 70 % is requiring to re-think the current supply chain. These trends changed the distribution process: delivery distances are decreasing, the product variety is increasing, and more products are being sold in smaller quantities. Therefore, the concept of supply chain resilience has gained more recognition in recent years. The scientific literature analysis conducted by the authors indicate several capabilities that influence supply chain resilience. Collaboration, flexibility, redundancy and integration are the most influential capabilities to supply chain resilience. However, the authors identify that the combination of these capabilities to supply chain resilience is under researched. The authors indicate that by combining these capabilities with the upcoming technologies of industry 4.0, supply chain resilience can be achieved. In the future, the authors are planning to conduct further research to identify the influence of these capabilities to supply chain resilience, to quantify supply chain resilience, and to provide further practices of industry 4.0 concept usage for supply chain resilience.

PENGELOLAAN KNOWLEDGE MANAGEMENT CAPABILITY DALAM MEMEDIASI DUKUNGAN INFORMATION TECHNOLOGY RELATEDNESS TERHADAP KINERJA PERUSAHAAN

Directory of Open Access Journals (Sweden)

Luluk Muhimatul Ifada

2011-06-01

Full Text Available The study examines whether or not and how information technology (IT relatedness influences corporate performance. This study proposes that knowledge management (KM is a critical organizational capability through which IT influences firm performance. Measurement of IT relatedness and KM capability uses a reflective second-order factor modeling approach for capturing complementarities among the four dimensions of IT relatedness (IT strategy making processes, IT vendor management processes, IT human resource management processes and IT infrastructure and for capturing complementarities among the three dimensions of KM capability (product KM capability, customer KM capability, and managerial KM capability. A survey was conducted among 93 branch managers of banking in Central Java. Structural Equation Model (SEM was used to analyze the data using the software program of SmartPLS (Partial Least Square. The findings support for the hypotheses of the study. IT relatedness of business units enhances the cross unit KM capability of the corporate. The KM capability creates and exploits cross-unit synergies from the product, customer, and managerial knowledge resources of the corporate. These synergies increase the corporate performance. IT relatedness of business units positively influences corporate performance. IT relatedness also has significant indirect effects on corporate performance through the mediation of KM capability.

NSR&D FY17 Report: CartaBlanca Capability Enhancements

Energy Technology Data Exchange (ETDEWEB)

Long, Christopher Curtis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dhakal, Tilak Raj [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zhang, Duan Zhong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-19

Over the last several years, particle technology in the CartaBlanca code has been matured and has been successfully applied to a wide variety of physical problems. It has been shown that the particle methods, especially Los Alamos's dual domain material point method, is capable of computing many problems involves complex physics, chemistries accompanied by large material deformations, where the traditional finite element or Eulerian method encounter significant difficulties. In FY17, the CartaBlanca code has been enhanced with physical models and numerical algorithms. We started out to compute penetration and HE safety problems. Most of the year we focused on the TEPLA model improvement testing against the sweeping wave experiment by Gray et al., because it was found that pore growth and material failure are essentially important for our tasks and needed to be understood for modeling the penetration and the can experiments efficiently. We extended the TEPLA mode from the point view of ensemble phase average to include the effects of nite deformation. It is shown that the assumed pore growth model in TEPLA is actually an exact result from the theory. Alone this line, we then generalized the model to include finite deformations to consider nonlinear dynamics of large deformation. The interaction between the HE product gas and the solid metal is based on the multi-velocity formation. Our preliminary numerical results suggest good agreement between the experiment and the numerical results, pending further verification. To improve the parallel processing capabilities of the CartaBlanca code, we are actively working with the Next Generation Code (NGC) project to rewrite selected packages using C++. This work is expected to continue in the following years. This effort also makes the particle technology developed with CartaBlanca project available to other part of the laboratory. Working with the NGC project and rewriting some parts of the code also given us an

Investor Behavior and Flow-through Capability in the US Stock Market.

Science.gov (United States)

Cano, Carlos; Jareño, Francisco; Tolentino, Marta

2016-01-01

This paper analyzes investor behavior depending on the flow-through capability (FTC) in the US stock market, because investors seek protection from inflation rate changes, and the FTC (a firm's ability to transmit inflation shocks to the prices of its products and services) is a key factor in investment decisions. Our estimates of the FTC of firms listed on the US stock exchange at the sector level are significantly different among industries, and we demonstrate a direct relationship between changes in stock prices (at the sector level) and FTC. These results would be relevant because they have important implications on investor behavior.

Shuttle performance enhancement using an uprated OMS engine

Science.gov (United States)

Mallini, Charles J.; Boyd, William C.

1988-01-01

The NASA Space Shuttle's Orbital Maneuvering Engine (OME) has been investigated as the basis for an enhancement of Shuttle operational flexibility. The Johnson Space Center has given attention to an upgrading of the OME through the use of a gas generator-driven turbopump to raise engine specific impulse. Hardware tests have demonstrated the projected performance gains, which will yield an enhanced, intact ascent-abort capability, as well an an improved on-orbit payload and altitude capability. Attention is given to the application of these capabilities to the Hubble Space Telescope's deployment.

Heat transfer enhancement in a turbulent natural convection boundary layer along a vertical flat plate

International Nuclear Information System (INIS)

Tsuji, Toshihiro; Kajitani, Tsuyoshi; Nishino, Tatsuhiko

2007-01-01

An experimental study on heat transfer enhancement for a turbulent natural convection boundary layer in air along a vertical flat plate has been performed by inserting a long flat plate in the spanwise direction (simple heat transfer promoter) and short flat plates aligned in the spanwise direction (split heat transfer promoter) with clearances into the near-wall region of the boundary layer. For a simple heat transfer promoter, the heat transfer coefficients increase by a peak value of approximately 37% in the downstream region of the promoter compared with those in the usual turbulent natural convection boundary layer. It is found from flow visualization and simultaneous measurements of the flow and thermal fields with hot- and cold-wires that such increase of heat transfer coefficients is mainly caused by the deflection of flows toward the outer region of the boundary layer and the invasion of low-temperature fluids from the outer region to the near-wall region with large-scale vortex motions riding out the promoter. However, heat transfer coefficients for a split heat transfer promoter exhibit an increase in peak value of approximately 60% in the downstream region of the promoter. Flow visualization and PIV measurements show that such remarkable heat transfer enhancement is attributed to longitudinal vortices generated by flows passing through the clearances of the promoter in addition to large-scale vortex motions riding out the promoter. Consequently, it is concluded that heat transfer enhancement of the turbulent natural convection boundary layer can be substantially achieved in a wide area of the turbulent natural convection boundary layer by employing multiple column split heat transfer promoters. It may be expected that the heat transfer enhancement in excess of approximately 40% can be accomplished by inserting such promoters

Second-Order Free-Riding on Antisocial Punishment Restores the Effectiveness of Prosocial Punishment

Science.gov (United States)

Szolnoki, Attila; Perc, Matjaž

2017-10-01

Economic experiments have shown that punishment can increase public goods game contributions over time. However, the effectiveness of punishment is challenged by second-order free-riding and antisocial punishment. The latter implies that noncooperators punish cooperators, while the former implies unwillingness to shoulder the cost of punishment. Here, we extend the theory of cooperation in the spatial public goods game by considering four competing strategies, which are traditional cooperators and defectors, as well as cooperators who punish defectors and defectors who punish cooperators. We show that if the synergistic effects are high enough to sustain cooperation based on network reciprocity alone, antisocial punishment does not deter public cooperation. Conversely, if synergistic effects are low and punishment is actively needed to sustain cooperation, antisocial punishment does is viable, but only if the cost-to-fine ratio is low. If the costs are relatively high, cooperation again dominates as a result of spatial pattern formation. Counterintuitively, defectors who do not punish cooperators, and are thus effectively second-order free-riding on antisocial punishment, form an active layer around punishing cooperators, which protects them against defectors that punish cooperators. A stable three-strategy phase that is sustained by the spontaneous emergence of cyclic dominance is also possible via the same route. The microscopic mechanism behind the reported evolutionary outcomes can be explained by the comparison of invasion rates that determine the stability of subsystem solutions. Our results reveal an unlikely evolutionary escape from adverse effects of antisocial punishment, and they provide a rationale for why second-order free-riding is not always an impediment to the evolutionary stability of punishment.

Second-Order Free-Riding on Antisocial Punishment Restores the Effectiveness of Prosocial Punishment

Directory of Open Access Journals (Sweden)

Attila Szolnoki

2017-10-01

Full Text Available Economic experiments have shown that punishment can increase public goods game contributions over time. However, the effectiveness of punishment is challenged by second-order free-riding and antisocial punishment. The latter implies that noncooperators punish cooperators, while the former implies unwillingness to shoulder the cost of punishment. Here, we extend the theory of cooperation in the spatial public goods game by considering four competing strategies, which are traditional cooperators and defectors, as well as cooperators who punish defectors and defectors who punish cooperators. We show that if the synergistic effects are high enough to sustain cooperation based on network reciprocity alone, antisocial punishment does not deter public cooperation. Conversely, if synergistic effects are low and punishment is actively needed to sustain cooperation, antisocial punishment does is viable, but only if the cost-to-fine ratio is low. If the costs are relatively high, cooperation again dominates as a result of spatial pattern formation. Counterintuitively, defectors who do not punish cooperators, and are thus effectively second-order free-riding on antisocial punishment, form an active layer around punishing cooperators, which protects them against defectors that punish cooperators. A stable three-strategy phase that is sustained by the spontaneous emergence of cyclic dominance is also possible via the same route. The microscopic mechanism behind the reported evolutionary outcomes can be explained by the comparison of invasion rates that determine the stability of subsystem solutions. Our results reveal an unlikely evolutionary escape from adverse effects of antisocial punishment, and they provide a rationale for why second-order free-riding is not always an impediment to the evolutionary stability of punishment.

Enhanced Capabilities for Subcritical Experiments (ECSE) Risk Management Plan

Energy Technology Data Exchange (ETDEWEB)

Urban, Mary Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Process Modeling and Analysis Group

2016-05-02

Risk is a factor, element, constraint, or course of action that introduces an uncertainty of outcome that could impact project objectives. Risk is an inherent part of all activities, whether the activity is simple and small, or large and complex. Risk management is a process that identifies, evaluates, handles, and monitors risks that have the potential to affect project success. The risk management process spans the entire project, from its initiation to its successful completion and closeout, including both technical and programmatic (non-technical) risks. This Risk Management Plan (RMP) defines the process to be used for identifying, evaluating, handling, and monitoring risks as part of the overall management of the Enhanced Capabilities for Subcritical Experiments (ECSE) ‘Project’. Given the changing nature of the project environment, risk management is essentially an ongoing and iterative process, which applies the best efforts of a knowledgeable project staff to a suite of focused and prioritized concerns. The risk management process itself must be continually applied throughout the project life cycle. This document was prepared in accordance with DOE O 413.3B, Program and Project Management for the Acquisition of Capital Assets, its associated guide for risk management DOE G 413.3-7, Risk Management Guide, and LANL ADPM AP-350-204, Risk and Opportunity Management.

Research for new UAV capabilities

Energy Technology Data Exchange (ETDEWEB)

Canavan, G.H.; Leadabrand, R.

1996-07-01

This paper discusses research for new Unmanned Aerial Vehicles (UAV) capabilities. Findings indicate that UAV performance could be greatly enhanced by modest research. Improved sensors and communications enhance near term cost effectiveness. Improved engines, platforms, and stealth improve long term effectiveness.

Capabilities, performance, and future possibilities of high frequency polyphase resonant converters

International Nuclear Information System (INIS)

Reass, W.A.; Baca, D.M.; Bradley, J.T. III; Hardek, T.W.; Kwon, S.I.; Lynch, M.T.; Rees, D.E.

2004-01-01

High Frequency Polyphase Resonant Power Conditioning (PRPC) techniques developed at Los Alamos National Laboratory (LANL) are now being utilized for the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) accelerator klystron RF amplifier power systems. Three different styles of polyphase resonant converter modulators were developed for the SNS application. The various systems operate up to 140 kV, or 11 MW pulses, or up to 1.1 MW average power, all from a DC input of +/- 1.2 kV. Component improvements realized with the SNS effort coupled with new applied engineering techniques have resulted in dramatic changes in RF power conditioning topology. As an example, the high-voltage transformers are over 100 times smaller and lighter than equivalent 60 Hz versions. With resonant conversion techniques, load protective networks are not required. A shorted load de-tunes the resonance and little power transfer can occur. This provides for power conditioning systems that are inherently self-protective, with automatic fault 'ride-through' capabilities. By altering the Los Alamos design, higher power and CW power conditioning systems can be realized without further demands of the individual component voltage or current capabilities. This has led to designs that can accommodate 30 MW long pulse applications and megawatt class CW systems with high efficiencies. The same PRPC techniques can also be utilized for lower average power systems (∼250 kW). This permits the use of significantly higher frequency conversion techniques that result in extremely compact systems with short pulse (10 to 100 us) capabilities. These lower power PRPC systems may be suitable for medical Linacs and mobile RF systems. This paper will briefly review the performance achieved for the SNS accelerator and examine designs for high efficiency megawatt class CW systems and 30 MW peak power applications. The devices and designs for compact higher frequency converters utilized for short pulse

Therapist-Designed Adaptive Riding in Children With Cerebral Palsy : Results of a Feasibility Study

NARCIS (Netherlands)

Angsupaisal, Mattana; Visser, Baudina; Alkema, Anne; Meinsma-van der Tuin, Marja; Maathuis, Carel G. B.; Reinders-Messelink, Heleen; Hadders-Algra, Mijna

Background. It is debatable whether adaptive riding (AR) in children with cerebral palsy (CP) improves postural control and gross motor development. Objective. The study aim was to explore the feasibility of an extensive assessment protocol for a randomized controlled trial of therapist-designed

Developing capability through peer-assisted learning activities ...

African Journals Online (AJOL)

L-CAS) is an activity by means of which each student is exposed to primary healthcare learning and practice in communities. Capability has been described as 'an integration of knowledge, skills, personal qualities and understanding used ...

The Ride of the Kings in Vlčnov from the Perspective of Contemporary Research

Czech Academy of Sciences Publication Activity Database

Stavělová, Daniela

2015-01-01

Roč. 25, č. 5 (2015), s. 47-64 ISSN 0862-8351 Institutional support: RVO:68378076 Keywords : Ride of the Kings * field research * methodology * festival * traditional custom * Vlčnov Subject RIV: AC - Archeology, Anthropology, Ethnology

Sally Ride EarthKAM - Automated Image Geo-Referencing Using Google Earth Web Plug-In

Science.gov (United States)

Andres, Paul M.; Lazar, Dennis K.; Thames, Robert Q.

2013-01-01

Sally Ride EarthKAM is an educational program funded by NASA that aims to provide the public the ability to picture Earth from the perspective of the International Space Station (ISS). A computer-controlled camera is mounted on the ISS in a nadir-pointing window; however, timing limitations in the system cause inaccurate positional metadata. Manually correcting images within an orbit allows the positional metadata to be improved using mathematical regressions. The manual correction process is time-consuming and thus, unfeasible for a large number of images. The standard Google Earth program allows for the importing of KML (keyhole markup language) files that previously were created. These KML file-based overlays could then be manually manipulated as image overlays, saved, and then uploaded to the project server where they are parsed and the metadata in the database is updated. The new interface eliminates the need to save, download, open, re-save, and upload the KML files. Everything is processed on the Web, and all manipulations go directly into the database. Administrators also have the control to discard any single correction that was made and validate a correction. This program streamlines a process that previously required several critical steps and was probably too complex for the average user to complete successfully. The new process is theoretically simple enough for members of the public to make use of and contribute to the success of the Sally Ride EarthKAM project. Using the Google Earth Web plug-in, EarthKAM images, and associated metadata, this software allows users to interactively manipulate an EarthKAM image overlay, and update and improve the associated metadata. The Web interface uses the Google Earth JavaScript API along with PHP-PostgreSQL to present the user the same interface capabilities without leaving the Web. The simpler graphical user interface will allow the public to participate directly and meaningfully with EarthKAM. The use of

Empirical study on the feasibility of measures for public self-protection capability enhancement

International Nuclear Information System (INIS)

Goersch, Henning G.; Werner, Ute

2011-01-01

The empirical study on the feasibility of measures for public self-protection capability enhancement covers the following issues with several sections: (1) Introduction: scope of the study; structure of the study. (2) Issue coherence: self-protection; reduction and prevention of damage by personal emergency preparedness, personal emergency preparedness in Germany. (3) Solution coherence: scientific approaches, development of practical problem solution approaches, proposal of a promotion system. (4) Empirical studies: Promotion system evaluation by experts; questioning of the public; Delphi-study on minimum standards in emergency preparedness; local networks in emergency preparedness. (5) Evaluation of models for personal emergency preparedness (M3P). (6) Integration of all research results into the approach of emergency preparedness: scope; recommendations, conclusions.

RIDES: Robust Intrusion Detection System for IP-Based Ubiquitous Sensor Networks

Directory of Open Access Journals (Sweden)

Sungwon Lee

2009-05-01

Full Text Available TheIP-based Ubiquitous Sensor Network (IP-USN is an effort to build the “Internet of things”. By utilizing IP for low power networks, we can benefit from existing well established tools and technologies of IP networks. Along with many other unresolved issues, securing IP-USN is of great concern for researchers so that future market satisfaction and demands can be met. Without proper security measures, both reactive and proactive, it is hard to envisage an IP-USN realm. In this paper we present a design of an IDS (Intrusion Detection System called RIDES (Robust Intrusion DEtection System for IP-USN. RIDES is a hybrid intrusion detection system, which incorporates both Signature and Anomaly based intrusion detection components. For signature based intrusion detection this paper only discusses the implementation of distributed pattern matching algorithm with the help of signature-code, a dynamically created attack-signature identifier. Other aspects, such as creation of rules are not discussed. On the other hand, for anomaly based detection we propose a scoring classifier based on the SPC (Statistical Process Control technique called CUSUM charts. We also investigate the settings and their effects on the performance of related parameters for both of the components.

Transitioning Enhanced Land Surface Initialization and Model Verification Capabilities to the Kenya Meteorological Department (KMD)

Science.gov (United States)

Case, Jonathan L.; Mungai, John; Sakwa, Vincent; Zavodsky, Bradley T.; Srikishen, Jayanthi; Limaye, Ashutosh; Blankenship, Clay B.

2016-01-01

Flooding, severe weather, and drought are key forecasting challenges for the Kenya Meteorological Department (KMD), based in Nairobi, Kenya. Atmospheric processes leading to convection, excessive precipitation and/or prolonged drought can be strongly influenced by land cover, vegetation, and soil moisture content, especially during anomalous conditions and dry/wet seasonal transitions. It is thus important to represent accurately land surface state variables (green vegetation fraction, soil moisture, and soil temperature) in Numerical Weather Prediction (NWP) models. The NASA SERVIR and the Short-term Prediction Research and Transition (SPoRT) programs in Huntsville, AL have established a working partnership with KMD to enhance its regional modeling capabilities. SPoRT and SERVIR are providing experimental land surface initialization datasets and model verification capabilities for capacity building at KMD. To support its forecasting operations, KMD is running experimental configurations of the Weather Research and Forecasting (WRF; Skamarock et al. 2008) model on a 12-km/4-km nested regional domain over eastern Africa, incorporating the land surface datasets provided by NASA SPoRT and SERVIR. SPoRT, SERVIR, and KMD participated in two training sessions in March 2014 and June 2015 to foster the collaboration and use of unique land surface datasets and model verification capabilities. Enhanced regional modeling capabilities have the potential to improve guidance in support of daily operations and high-impact weather and climate outlooks over Eastern Africa. For enhanced land-surface initialization, the NASA Land Information System (LIS) is run over Eastern Africa at 3-km resolution, providing real-time land surface initialization data in place of interpolated global model soil moisture and temperature data available at coarser resolutions. Additionally, real-time green vegetation fraction (GVF) composites from the Suomi-NPP VIIRS instrument is being incorporated

A Semiactive and Adaptive Hybrid Control System for a Tracked Vehicle Hydropneumatic Suspension Based on Disturbance Identification

Directory of Open Access Journals (Sweden)

Shousong Han

2017-01-01

Full Text Available The riding conditions for a high-speed tracked vehicle are quite complex. To enhance the adaptability of suspension systems to different riding conditions, a semiactive and self-adaptive hybrid control strategy based on disturbance velocity and frequency identification was proposed. A mathematical model of the semiactive, self-adaptive hybrid suspension control system, along with a performance evaluation function, was established. Based on a two-degree-of-freedom (DOF suspension system, the kinematic relations and frequency zero-crossing detection method were defined, and expressions for the disturbance velocity and disturbance frequency of the road were obtained. Optimal scheduling of the semiactive hybrid damping control gain (csky, cground, chybrid and self-adaptive control gain (cv under different disturbances were realized by exploiting the particle swarm multiobjective optimization algorithm. An experimental study using a carefully designed test rig was performed under a number of typical riding conditions of tracked vehicles, and the results showed that the proposed control strategy is capable of accurately recognizing different disturbances, shifting between control modes (semiactive/self-adaptive, and scheduling the damping control gain according to the disturbance identification outcomes; hence, the proposed strategy could achieve a good trade-off between ride comfort and ride safety and efficiently increase the overall performance of the suspension under various riding conditions.

National Aeronautics and Space Administration (NASA) Environmental Control and Life Support (ECLS) Capability Roadmap Development for Exploration

Science.gov (United States)

Bagdigian, Robert M.; Carrasquillo, Robyn L.; Metcalf, Jordan; Peterson, Laurie

2012-01-01

NASA is considering a number of future human space exploration mission concepts. Although detailed requirements and vehicle architectures remain mostly undefined, near-term technology investment decisions need to be guided by the anticipated capabilities needed to enable or enhance the mission concepts. This paper describes a roadmap that NASA has formulated to guide the development of Environmental Control and Life Support Systems (ECLSS) capabilities required to enhance the long-term operation of the International Space Station (ISS) and enable beyond-Low Earth Orbit (LEO) human exploration missions. Three generic mission types were defined to serve as a basis for developing a prioritized list of needed capabilities and technologies. Those are 1) a short duration micro gravity mission; 2) a long duration transit microgravity mission; and 3) a long duration surface exploration mission. To organize the effort, ECLSS was categorized into three major functional groups (atmosphere, water, and solid waste management) with each broken down into sub-functions. The ability of existing, flight-proven state-of-the-art (SOA) technologies to meet the functional needs of each of the three mission types was then assessed. When SOA capabilities fell short of meeting the needs, those "gaps" were prioritized in terms of whether or not the corresponding capabilities enable or enhance each of the mission types. The resulting list of enabling and enhancing capability gaps can be used to guide future ECLSS development. A strategy to fulfill those needs over time was then developed in the form of a roadmap. Through execution of this roadmap, the hardware and technologies needed to enable and enhance exploration may be developed in a manner that synergistically benefits the ISS operational capability, supports Multi-Purpose Crew Vehicle (MPCV) development, and sustains long-term technology investments for longer duration missions. This paper summarizes NASA s ECLSS capability roadmap

Comparing the impacts of hiking, skiing and horse riding on trail and vegetation in different types of forest.

Science.gov (United States)

Törn, A; Tolvanen, A; Norokorpi, Y; Tervo, R; Siikamäki, P

2009-03-01

Nature-based tourism in protected areas has increased and diversified dramatically during the last decades. Different recreational activities have a range of impacts on natural environments. This paper reports results from a comparison of the impacts of hiking, cross-country skiing and horse riding on trail characteristics and vegetation in northern Finland. Widths and depths of existing trails, and vegetation on trails and in the neighbouring forests were monitored in two research sites during 2001 and 2002. Trail characteristics and vegetation were clearly related to the recreational activity, research site and forest type. Horse trails were as deep as hiking trails, even though the annual number of users was 150-fold higher on the hiking trails. Simultaneously, cross-country skiing had the least effect on trails due to the protective snow cover during winter. Hiking trail plots had little or no vegetation cover, horse riding trail plots had lower vegetation cover than forest plots, while skiing had no impact on total vegetation cover. On the other hand, on horse riding trails there were more forbs and grasses, many of which did not grow naturally in the forest. These species that were limited to riding trails may change the structure of adjacent plant communities in the long run. Therefore, the type of activities undertaken and the sensitivity of habitats to these activities should be a major consideration in the planning and management of nature-based tourism. Establishment of artificial structures, such as stairs, duckboards and trail cover, or complete closure of the site, may be the only way to protect the most sensitive or deteriorated sites.

Withania somnifera Root Extract Enhances Chemotherapy through 'Priming'.

Directory of Open Access Journals (Sweden)

Aine Brigette Henley

Full Text Available Withania somnifera extracts are known for their anti-cancerous, anti-inflammatory and antioxidative properties. One of their mechanisms of actions is to modulate mitochondrial function through increasing oxidative stress. Recently 'priming' has been suggested as a potential mechanism for enhancing cancer cell death. In this study we demonstrate that 'priming', in HT-29 colon cells, with W. somnifera root extract increased the potency of the chemotherapeutic agent cisplatin. We have also showed the W. somnifera root extract enhanced mitochondrial dysfunction and that the underlying mechanism of 'priming' was selectively through increased ROS. Moreover, we showed that this effect was not seen in non-cancerous cells.

A behavioral choice model of the use of car-sharing and ride-sourcing services

Energy Technology Data Exchange (ETDEWEB)

Dias, Felipe F.; Lavieri, Patrícia S.; Garikapati, Venu M.; Astroza, Sebastian; Pendyala, Ram M.; Bhat, Chandra R.

2017-07-26

There are a number of disruptive mobility services that are increasingly finding their way into the marketplace. Two key examples of such services are car-sharing services and ride-sourcing services. In an effort to better understand the influence of various exogenous socio-economic and demographic variables on the frequency of use of ride-sourcing and car-sharing services, this paper presents a bivariate ordered probit model estimated on a survey data set derived from the 2014-2015 Puget Sound Regional Travel Study. Model estimation results show that users of these services tend to be young, well-educated, higher-income, working individuals residing in higher-density areas. There are significant interaction effects reflecting the influence of children and the built environment on disruptive mobility service usage. The model developed in this paper provides key insights into factors affecting market penetration of these services, and can be integrated in larger travel forecasting model systems to better predict the adoption and use of mobility-on-demand services.

Applications of contrast enhanced CT through external jugular access

International Nuclear Information System (INIS)

Xu Qiaolan; Zou Wenxing; Chen Meixia; Xie Hongbo

2005-01-01

Objective: A retrospective analysis and evaluation for the effects of contrast enhanced computed tomography through external jugular access. Methods: 1250 cases (male 692 and female 558) underwent CT contrast enhanced examination were retrospectively reviewed from May, 2002 to Oct, 2002. The patients aged from 12 to 86 years, averagely 49 years. Contrast agent (Ultravist) was given through an intravenous catheter placed in the cubital vein. Precise injection rates were ensured by a power injector (Medrad MCT310, USA). Excellent enhancement was achieved with this protocol in most of the patients, while external jugular access was established in 96 cases because it was unable to setup a cubital venous access. Results: Good enhancement were acquired when 96 cases of contrast agent injected through external jugular vein. And the external jugular access was setup successfully with a single puncture. Conclusion: It is a common occasion when patient undergoing contrast enhanced CT scan is in poor conditions: debility, cachexia, or with complication of chemotherapy or radiation therapy, which often results in invalidity of cabital venous access, and consequently, making bolus injection impossible. The external jugular vein is a large and central blood vessel, which is easy to setup an access. In our experience, an external jugular access should be recommended as a substitution if the cubital venous access is not available. (authors)

Applications of contrast enhanced CT through external jugular access

Energy Technology Data Exchange (ETDEWEB)

Qiaolan, Xu; Wenxing, Zou; Meixia, Chen; Hongbo, Xie [The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China). Dept. of Radiology

2005-09-15

Objective: A retrospective analysis and evaluation for the effects of contrast enhanced computed tomography through external jugular access. Methods: 1250 cases (male 692 and female 558) underwent CT contrast enhanced examination were retrospectively reviewed from May, 2002 to Oct, 2002. The patients aged from 12 to 86 years, averagely 49 years. Contrast agent (Ultravist) was given through an intravenous catheter placed in the cubital vein. Precise injection rates were ensured by a power injector (Medrad MCT310, USA). Excellent enhancement was achieved with this protocol in most of the patients, while external jugular access was established in 96 cases because it was unable to setup a cubital venous access. Results: Good enhancement were acquired when 96 cases of contrast agent injected through external jugular vein. And the external jugular access was setup successfully with a single puncture. Conclusion: It is a common occasion when patient undergoing contrast enhanced CT scan is in poor conditions: debility, cachexia, or with complication of chemotherapy or radiation therapy, which often results in invalidity of cabital venous access, and consequently, making bolus injection impossible. The external jugular vein is a large and central blood vessel, which is easy to setup an access. In our experience, an external jugular access should be recommended as a substitution if the cubital venous access is not available. (authors)

Rüütel pensionäride elujärje garandina / Janno Reiljan

Index Scriptorium Estoniae

Reiljan, Janno, 1951-2018

2006-01-01

Ilmunud ka: Severnoje Poberezhje (2006) 17. aug., lk. 2, Meie Maa (2006) 18. aug., lk. 2, Nädaline (2006) 22. aug., lk. 2, Vooremaa (2006) 22. aug., lk. 2, Valgamaalane (2006) 24. aug., lk. 2. Autor selgitab Eesti pensionäride elujärje kujunemise näitel, miks Rahvaliit ja Keskerakond nimetasid oma koostöölepingu garandiks president Arnold Rüütli

Enhancing Education through Mobile Augmented Reality

Science.gov (United States)

Joan, D. R. Robert

2015-01-01

In this article, the author has discussed about the Mobile Augmented Reality and enhancing education through it. The aim of the present study was to give some general information about mobile augmented reality which helps to boost education. Purpose of the current study reveals the mobile networks which are used in the institution campus as well…

Issues in motorcycle sensory and cognitive conspicuity: the impact of motorcycle low-beam headlights and riding experience on drivers' decisions to turn across the path of a motorcycle.

Science.gov (United States)

Mitsopoulos-Rubens, Eve; Lenné, Michael G

2012-11-01

Crashes involving a passenger car and a motorcycle, where the car is turning across the path of the motorcycle, are a major crash type of motorcycle riders. It has been proposed that the incidence of such crashes could be reduced through improvements in motorcycle conspicuity. Operation of low-beam headlights on motorcycles has been discussed as one approach for improving the "sensory conspicuity" of motorcycles during daylight hours, whilst previous experience as a rider may serve to heighten "cognitive conspicuity" through raised awareness of motorcyclists on our roads. Twenty-three experienced car drivers with no riding experience ("drivers") and 20 experienced car drivers who were also motorcycle riders ("driver-riders") completed a series of trials in a driving simulator where their task in each trial was to turn ahead of an oncoming vehicle if they felt that they had sufficient room to do so safely. A key manipulation across trials was whether the oncoming vehicle was a motorcycle with headlights on, or a motorcycle with headlights off. Time gap (short, medium, long) was also manipulated. Results indicate that, at time gaps defined in the current study as short, low-beam headlights may confer some benefit in gap acceptance by encouraging drivers to accept fewer gaps ahead of a motorcycle with headlights on than ahead of a motorcycle with headlights off. No statistically significant differences in gap acceptance between the headlight conditions were found at either the medium or long time gaps. Irrespective of time gap, driver-riders were found to adopt a more efficient turn strategy than drivers with no direct riding experience. Overall, the present research provides support for the use of low-beam headlights and riding experience as tools through which to augment the sensory and cognitive conspicuity of motorcycles, respectively. It is proposed that further research aim to explore directly the precise mechanisms underlying the observed effects. Copyright �

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.

Gossiping Capabilities

DEFF Research Database (Denmark)

Mogensen, Martin; Frey, Davide; Guerraoui, Rachid

Gossip-based protocols are now acknowledged as a sound basis to implement collaborative high-bandwidth content dissemination: content location is disseminated through gossip, the actual contents being subsequently pulled. In this paper, we present HEAP, HEterogeneity Aware gossip Protocol, where...... nodes dynamically adjust their contribution to gossip dissemination according to their capabilities. Using a continuous, itself gossip-based, approximation of relative capabilities, HEAP dynamically leverages the most capable nodes by (a) increasing their fanouts (while decreasing by the same proportion...... declare a high capability in order to augment their perceived quality without contributing accordingly. We evaluate HEAP in the context of a video streaming application on a 236 PlanetLab nodes testbed. Our results shows that HEAP improves the quality of the streaming by 25% over a standard gossip...

Organisational Capabilities Required for Enabling Employee Mobility through Bring- Your-Own-Device Concept

Directory of Open Access Journals (Sweden)

Toperesu B-Abee

2017-03-01

Full Text Available Background: Mobile device adoption is on the rise and people are increasingly using mobile devices as a part of their lives. Studies have shown that people can use mobile devices to perform their work duties from anywhere. Organisations are now exploring ways of enabling and supporting mobility for employees’ mobile devices, including BYOD (Bring-Your-Own-Device policies. Objective: The objective of this study is to identify the main capabilities required for enterprise mobility. Methods/Approach: This qualitative research study presents empirical results based on interviews with selected senior IS managers of large organizations. Results: The main findings of this study suggest that information security and mobile device management are among the main capabilities required for enterprise mobility. Conclusions: Enterprise mobility is an emerging field which has received very little research attention. More research in the field will help organisations make informed decisions on how to increase productivity, sales and efficiency while achieving employee satisfaction through enterprise mobility.

Capable design or designing capabilities? An exploration of service design as an emerging organizational capability in Telenor – Martinkenaite

Directory of Open Access Journals (Sweden)

Ieva Martinkenaite

2017-01-01

Full Text Available This empirical paper examines a process, starting with the managerial decision to make service design an organizational capability, and follows it as it unfolds over time within one organization. Service design has become an established business practice of how firms create new products and services to promote differentiation in an increasingly uncertain business landscape. Implicit in the literature on service design are assumptions about strategic implications of adopting the prescribed innovation methods and tools. However, little is known about how service design evolves into an organizational capability enabling firms to transform their existing businesses and sustain competitiveness. Through a longitudinal, exploratory case study of service design practices in one of the world’s largest telecommunications companies, we explicate mechanisms through which service design evolves into an organizational capability by exploring the research question: what are the mechanisms through which service design develops into an organizational capability? Our study reveals the effect of an initial introduction of service design tools, identification of boundaryspanning actors and co-alignment of dedicated resources between internal functions, as well as through co-creation with customers. Over time, these activities lead to the adoption of service design practices, and subsequently these practices spark incremental learning throughout the organization, alter managerial decisions and influence multiple paths for the development of new capabilities. Reporting on this process, we are able to describe how service design practices were disseminated and institutionalized within the organization we observed. This study thus contributes by informing how service design can evolve into an organizational capability, as well as by bridging the emerging literature on service design and design thinking with established strategy theory. Further research will have to

Solvothermal preparation of micro/nanostructured TiO{sub 2} with enhanced lithium storage capability

Energy Technology Data Exchange (ETDEWEB)

Li, Jie [School of Physics and Mechanical & Electronical Engineering, Hubei University of Education, Wuhan, 430205 (China); Wang, Chao [Department of Architecture and Material Engineering, Hubei University of Education, Wuhan, 430205 (China); Zheng, Ping; Zhang, Lei; Chen, Gongxuan [College of Chemistry and Life Science, Hubei University of Education, Wuhan, 430205 (China); Tang, Chengchun [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Wu, Tian, E-mail: twu@whu.edu.cn [School of Physics and Mechanical & Electronical Engineering, Hubei University of Education, Wuhan, 430205 (China); College of Chemistry and Life Science, Hubei University of Education, Wuhan, 430205 (China); Department of Architecture and Material Engineering, Hubei University of Education, Wuhan, 430205 (China)

2017-04-01

Facile and controllable preparation of TiO{sub 2} is of prime importance to elaborately tailor and then fully exploit its intriguing functionalities in energy storage, catalysis and environmental remediation. Herein, a solvothermal method combined with post annealing is conducted, in which the hydrolysis of tetrabutyl titanate is controlled by the in-situ generated water during solvothermal treatment. By controlling synthetic conditions (i.e. reactant ratio, solvothermal temperature and reaction time), we manage to tailor the morphologies of TiO{sub 2}. Specially, three typical structures (nanoparticle, nanoneedle and nanorod) are studied to reveal the growth mechanism and the effects of the synthesis conditions. Nanoneedle-structured TiO{sub 2} shows higher specific capacity and enhanced cycle stability as anode material for lithium ion batteries. - Highlights: • Controllable preparation of nano-TiO{sub 2} is achieved by a solvothermal method. • TiO{sub 2} morphology is tailored by tuning reactant ratio, temperature and duration. • Needle structured TiO{sub 2} shows enhanced lithium storage capability.

Enhancing regional security agreements through cooperative monitoring

International Nuclear Information System (INIS)

Pregenzer, A.L.

1995-05-01

This paper proposes that strengthening regional capabilities for formulating and implementing arms control and confidence-building measures is a tangible method of enhancing regional security. It discusses the importance of developing a regional infrastructure for arms control and confidence building and elucidates the role of technology in facilitating regional arms control and confidence-building agreements. In addition, it identifies numerous applications for regional cooperative monitoring in the areas of arms control, resource management, international commerce and disaster response. The Cooperative Monitoring Center at Sandia National Laboratories, whose aim is to help individual countries and regions acquire the tools they need to develop their own solutions to regional problems, is discussed briefly. The paper ends with recommendations for establishing regional cooperative monitoring centers

Speech Auditory Alerts Promote Memory for Alerted Events in a Video-Simulated Self-Driving Car Ride.

Science.gov (United States)

Nees, Michael A; Helbein, Benji; Porter, Anna

2016-05-01

Auditory displays could be essential to helping drivers maintain situation awareness in autonomous vehicles, but to date, few or no studies have examined the effectiveness of different types of auditory displays for this application scenario. Recent advances in the development of autonomous vehicles (i.e., self-driving cars) have suggested that widespread automation of driving may be tenable in the near future. Drivers may be required to monitor the status of automation programs and vehicle conditions as they engage in secondary leisure or work tasks (entertainment, communication, etc.) in autonomous vehicles. An experiment compared memory for alerted events-a component of Level 1 situation awareness-using speech alerts, auditory icons, and a visual control condition during a video-simulated self-driving car ride with a visual secondary task. The alerts gave information about the vehicle's operating status and the driving scenario. Speech alerts resulted in better memory for alerted events. Both auditory display types resulted in less perceived effort devoted toward the study tasks but also greater perceived annoyance with the alerts. Speech auditory displays promoted Level 1 situation awareness during a simulation of a ride in a self-driving vehicle under routine conditions, but annoyance remains a concern with auditory displays. Speech auditory displays showed promise as a means of increasing Level 1 situation awareness of routine scenarios during an autonomous vehicle ride with an unrelated secondary task. © 2016, Human Factors and Ergonomics Society.

Individual differences in behavioural inhibition explain free riding in public good games when punishment is expected but not implemented

Science.gov (United States)

2013-01-01

Background The literature on social dilemmas and punishment focuses on the behaviour of the punisher. However, to fully explain the effect of punishment on cooperation, it is important to understand the psychological mechanisms influencing the behaviour of those who expect to be punished. This paper examines whether the expectation of punishment, rather than the implementation of punishment is sufficient to prevent individuals from free riding. Individual differences in the punishment sensitivity have been linked to both threat responses (flight, fight, fear system, or the FFFS) and to the response to the uncertainty of punishment (BIS-anxiety).The paper, therefore, examines if individual differences in BIS-anxiety and FFFS can explain some of the variability in free riding in the face of implemented and non-implemented punishment. Methods Participants took part in a series of one-shot Public Goods Games (PGGs) facing two punishment conditions (implemented and non-implemented) and two standard non-punishment PGGs. The punishment was implemented as a centralized authority punishment (i.e., if one participant contributed less than their group members, they were automatically fined). Individual contribution levels and presence/absence of zero contributions indexed free riding. Individual differences in behavioural inhibition were assessed. Results Individuals contributed more under the threat of punishment (both implemented and non-implemented). However, individuals contributed less when the punishment was not implemented compared to when it was. Those scoring high in BIS-anxiety contributed more when the punishment expectations were not implemented. This effect was not observed for FFFS. Conclusion Supporting previous research, punishment had a powerful effect in increasing contribution levels in the PGGs. However, when expected punishment was not implemented, individual differences in punishment sensitivity, specifically in BIS-anxiety, were related to fewer

Individual differences in behavioural inhibition explain free riding in public good games when punishment is expected but not implemented

Directory of Open Access Journals (Sweden)

Skatova Anya

2013-01-01

Full Text Available Abstract Background The literature on social dilemmas and punishment focuses on the behaviour of the punisher. However, to fully explain the effect of punishment on cooperation, it is important to understand the psychological mechanisms influencing the behaviour of those who expect to be punished. This paper examines whether the expectation of punishment, rather than the implementation of punishment is sufficient to prevent individuals from free riding. Individual differences in the punishment sensitivity have been linked to both threat responses (flight, fight, fear system, or the FFFS and to the response to the uncertainty of punishment (BIS-anxiety.The paper, therefore, examines if individual differences in BIS-anxiety and FFFS can explain some of the variability in free riding in the face of implemented and non-implemented punishment. Methods Participants took part in a series of one-shot Public Goods Games (PGGs facing two punishment conditions (implemented and non-implemented and two standard non-punishment PGGs. The punishment was implemented as a centralized authority punishment (i.e., if one participant contributed less than their group members, they were automatically fined. Individual contribution levels and presence/absence of zero contributions indexed free riding. Individual differences in behavioural inhibition were assessed. Results Individuals contributed more under the threat of punishment (both implemented and non-implemented. However, individuals contributed less when the punishment was not implemented compared to when it was. Those scoring high in BIS-anxiety contributed more when the punishment expectations were not implemented. This effect was not observed for FFFS. Conclusion Supporting previous research, punishment had a powerful effect in increasing contribution levels in the PGGs. However, when expected punishment was not implemented, individual differences in punishment sensitivity, specifically in BIS-anxiety, were

Therapeutic Riding for a Student with Multiple Disabilities and Visual Impairment: A Case Study.

Science.gov (United States)

Lehrman, Jennifer; Ross, David B.

2001-01-01

A 9-year-old with multiple disabilities and visual impairments was the focus of a 10-week developmental therapeutic riding program incorporating hippotherapy. The program has led to increased mobility, an increase in visual attention span and fixation time, signs of greater verbal communication, and the acquisition of new functional signs.…

Available decontamination and decommissioning capabilities at the Savannah River Technology Center

International Nuclear Information System (INIS)

Polizzi, L.M.; Norkus, J.K.; Paik, I.K.; Wooten, L.A.

1992-01-01

The Safety Analysis and Engineering Services Group has performed a survey of the Savannah River Technology Center (SRTC) technical capabilities, skills, and experience in Decontamination and Decommissioning (D ampersand D) activities. The goal of this survey is to enhance the integration of the SRTC capabilities with the technical needs of the Environmental Restoration Department D ampersand D program and the DOE Office of Technology Development through the Integrated Demonstration Program. This survey has identified technical capabilities, skills, and experience in the following D ampersand D areas: Characterization, Decontamination, Dismantlement, Material Disposal, Remote Systems, and support on Safety Technology for D ampersand D. This review demonstrates the depth and wealth of technical capability resident in the SRTC in relation to these activities, and the unique qualifications of the SRTC to supply technical support in the area of DOE facility D ampersand D. Additional details on specific technologies and applications to D ampersand D will be made available on request

Rethinking capacity building for knowledge mobilisation: developing multilevel capabilities in healthcare organisations.

Science.gov (United States)

Kislov, Roman; Waterman, Heather; Harvey, Gill; Boaden, Ruth

2014-11-15

Knowledge mobilisation in healthcare organisations is often carried out through relatively short-term projects dependent on limited funding, which raises concerns about the long-term sustainability of implementation and improvement. It is becoming increasingly recognised that the translation of research evidence into practice has to be supported by developing the internal capacity of healthcare organisations to engage with and apply research. This process can be supported by external knowledge mobilisation initiatives represented, for instance, by professional associations, collaborative research partnerships and implementation networks. This conceptual paper uses empirical and theoretical literature on organisational learning and dynamic capabilities to enhance our understanding of intentional capacity building for knowledge mobilisation in healthcare organisations. The discussion is structured around the following three themes: (1) defining and classifying capacity building for knowledge mobilisation; (2) mechanisms of capability development in organisational context; and (3) individual, group and organisational levels of capability development. Capacity building is presented as a practice-based process of developing multiple skills, or capabilities, belonging to different knowledge domains and levels of complexity. It requires an integration of acquisitive learning, through which healthcare organisations acquire knowledge and skills from knowledge mobilisation experts, and experience-based learning, through which healthcare organisations adapt, absorb and modify their knowledge and capabilities through repeated practice. Although the starting point for capability development may be individual-, team- or organisation-centred, facilitation of the transitions between individual, group and organisational levels of learning within healthcare organisations will be needed. Any initiative designed to build capacity for knowledge mobilisation should consider the

On the temperature dependence of H-Uiso in the riding hydrogen model

International Nuclear Information System (INIS)

Lübben, Jens; Volkmann, Christian; Grabowsky, Simon; Edwards, Alison; Morgenroth, Wolfgang; Fabbiani, Francesca P. A.; Sheldrick, George M.; Dittrich, Birger

2014-01-01

The temperature dependence of hydrogen U iso and parent U eq in the riding hydrogen model is investigated by neutron diffraction, aspherical-atom refinements and QM/MM and MO/MO cluster calculations. Fixed values of 1.2 or 1.5 appear to be underestimated, especially at temperatures below 100 K. The temperature dependence of H-U iso in N-acetyl-l-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U iso below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffraction data to high resolution, collected at temperatures of 9, 30, 50, 75, 100, 150, 200 and 250 K (synchrotron and home source), reproduce neutron results only when evaluated by aspherical-atom refinement models, since these take into account bonding and lone-pair electron density; both invariom and Hirshfeld-atom refinement models enable a more precise determination of the magnitude of H-atom displacements than independent-atom model refinements. Experimental efforts are complemented by computing displacement parameters following the TLS+ONIOM approach. A satisfactory agreement between all approaches is found

Substantial enhancement of energy storage capability in polymer nanocomposites by encapsulation of BaTiO3 NWs with variable shell thickness.

Science.gov (United States)

Wang, Guanyao; Huang, Yanhui; Wang, Yuxin; Jiang, Pingkai; Huang, Xingyi

2017-08-09

Dielectric polymer nanocomposites have received keen interest due to their potential application in energy storage. Nevertheless, the large contrast in dielectric constant between the polymer and nanofillers usually results in a significant decrease of breakdown strength of the nanocomposites, which is unfavorable for enhancing energy storage capability. Herein, BaTiO 3 nanowires (NWs) encapsulated by TiO 2 shells of variable thickness were utilized to fabricate dielectric polymer nanocomposites. Compared with nanocomposites with bare BaTiO 3 NWs, significantly enhanced energy storage capability was achieved for nanocomposites with TiO 2 encapsulated BaTiO 3 NWs. For instance, an ultrahigh energy density of 9.53 J cm -3 at 440 MV m -1 could be obtained for nanocomposites comprising core-shell structured nanowires, much higher than that of nanocomposites with 5 wt% raw ones (5.60 J cm -3 at 360 MV m -1 ). The discharged energy density of the proposed nanocomposites with 5 wt% mTiO 2 @BaTiO 3 -1 NWs at 440 MV m -1 seems to rival or exceed those of some previously reported nanocomposites (mostly comprising core-shell structured nanofillers). More notably, this study revealed that the energy storage capability of the nanocomposites can be tailored by the TiO 2 shell thickness. Finite element simulations were employed to analyze the electric field distribution in the nanocomposites. The enhanced energy storage capability should be mainly attributed to the smoother gradient of dielectric constant between the nanofillers and polymer matrix, which alleviated the electric field concentration and leakage current in the polymer matrix. The methods and results herein offer a feasible approach to construct high-energy-density polymer nanocomposites with core-shell structured nanowires.

How challenging is a riding horse’s life? Field studies on fitness, workload and welfare

NARCIS (Netherlands)

Munsters, C.C.B.M.

2013-01-01

The objectives of this thesis were to evaluate in practice workload, fitness and welfare of riding horses under work and training conditions. Chapter II presents an overview of the parameters used in earlier studies on training, behaviour and equine welfare, and describes the evaluation of the

The choice of Park & Ride Facilities: an analysis using a context-dependent hierarchical choice experiment

NARCIS (Netherlands)

Heijden, R.E.C.M. van der; Molin, E.J.E.; Timmermans, H.J.P.

2004-01-01

Park and Ride facilities have been proposed in several countries to alleviate the accessibility problems in cities. Despite growing accessibility problems, these facilities do not seem to attract the expected number of car drivers and are under-used. In an attempt to measure consumer evaluations of

The choice of park & ride facilities : an analysis using a context-dependent hierarchical choice experiment

NARCIS (Netherlands)

Bos, D.M.; vd Heijden, R.E.C.M.; Molin, E.J.E.; Timmermans, H.J.P.

2004-01-01

Park and Ride facilities have been proposed in several countries to alleviate the accessibility problems in cities. Despite growing accessibility problems, these facilities do not seem to attract the expected number of car drivers and are under-used. In an attempt to measure consumer evaluations of

Enhancing learning in tertiary institutions through multimedia based ...

African Journals Online (AJOL)

Enhancing learning in tertiary institutions through multimedia based ... convenient and cost-effective courseware reengineering methodology of our age. ... Also discussed are the reasons for converting classroom courses to e-learning format.

Hanford River Protection Project Enhanced Mission Planning Through Innovative Tools: Lifecycle Cost Modeling And Aqueous Thermodynamic Modeling - 12134

International Nuclear Information System (INIS)

Pierson, K.L.; Meinert, F.L.

2012-01-01

Two notable modeling efforts within the Hanford Tank Waste Operations Simulator (HTWOS) are currently underway to (1) increase the robustness of the underlying chemistry approximations through the development and implementation of an aqueous thermodynamic model, and (2) add enhanced planning capabilities to the HTWOS model through development and incorporation of the lifecycle cost model (LCM). Since even seemingly small changes in apparent waste composition or treatment parameters can result in large changes in quantities of high-level waste (HLW) and low-activity waste (LAW) glass, mission duration or lifecycle cost, a solubility model that more accurately depicts the phases and concentrations of constituents in tank waste is required. The LCM enables evaluation of the interactions of proposed changes on lifecycle mission costs, which is critical for decision makers.

Riding Bare-Back on unstructured meshes for 21. century criticality calculations - 244

International Nuclear Information System (INIS)

Kelley, K.C.; Martz, R.L.; Crane, D.L.

2010-01-01

MCNP has a new capability that permits tracking of neutrons and photons on an unstructured mesh which is embedded as a mesh universe within its legacy geometry capability. The mesh geometry is created through Abaqus/CAE using its solid modeling capabilities. Transport results are calculated for mesh elements through a path length estimator while element to element tracking is performed on the mesh. The results from MCNP can be exported to Abaqus/CAE for visualization or other-physics analysis. The simple Godiva criticality benchmark problem was tested with this new mesh capability. Computer run time is proportional to the number of mesh elements used. Both first and second order polyhedrons are used. Models that used second order polyhedrons produced slightly better results without significantly increasing computer run time. Models that used first order hexahedrons had shorter runtimes than models that used first order tetrahedrons. (authors)

Management of lower extremity riding lawn mower injuries in children.

Science.gov (United States)

Kroening, L; Davids, J R

2000-01-01

Eight children are injured by riding lawn mowers every day. The child, usually a bystander or passenger on the mower, can sustain life-threatening and limb-threatening injuries. Multidisciplinary care must be available to manage the numerous issues presented by the unique circumstance of a child with a severe injury in the acute and chronic settings. Whether the limb is salvaged or amputated, the ultimate goal is optimal functional outcome for the patient. We have developed a team approach to address these injuries from their onset until patient maturity, maximizing our ability to achieve this goal.

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

DEFF Research Database (Denmark)

Liu, Wenzhao; Guo, Xiaoqiang; Sulligoi, Giorgio

2016-01-01

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

Transient stability improvement: a review and comparison of conventional and renewable-based techniques for preventive and emergency control

DEFF Research Database (Denmark)

Pertl, Michael; Weckesser, Johannes Tilman Gabriel; Rezkalla, Michel M.N.

2017-01-01

increases the voltage setpoint of the units in order to increase the synchronizing power, is reported. Regarding renewable energy source based emergency control, low voltage ride-through (LVRT) capability including voltage support is a well established method. Nevertheless, it is also highlighted that high...

Experimental investigation of biodynamic human body models subjected to whole-body vibration during a vehicle ride.

Science.gov (United States)

Taskin, Yener; Hacioglu, Yuksel; Ortes, Faruk; Karabulut, Derya; Arslan, Yunus Ziya

2018-02-06

In this study, responses of biodynamic human body models to whole-body vibration during a vehicle ride were investigated. Accelerations were acquired from three different body parts, such as the head, upper torso and lower torso, of 10 seated passengers during a car ride while two different road conditions were considered. The same multipurpose vehicle was used during all experiments. Additionally, by two widely used biodynamic models in the literature, a set of simulations were run to obtain theoretical accelerations of the models and were compared with those obtained experimentally. To sustain a quantified comparison between experimental and theoretical approaches, the root mean square acceleration and acceleration spectral density were calculated. Time and frequency responses of the models demonstrated that neither of the models showed the best prediction performance of the human body behaviour in all cases, indicating that further models are required for better prediction of the human body responses.

Advancing Drug Discovery through Enhanced Free Energy Calculations.

Science.gov (United States)

Abel, Robert; Wang, Lingle; Harder, Edward D; Berne, B J; Friesner, Richard A

2017-07-18

A principal goal of drug discovery project is to design molecules that can tightly and selectively bind to the target protein receptor. Accurate prediction of protein-ligand binding free energies is therefore of central importance in computational chemistry and computer aided drug design. Multiple recent improvements in computing power, classical force field accuracy, enhanced sampling methods, and simulation setup have enabled accurate and reliable calculations of protein-ligands binding free energies, and position free energy calculations to play a guiding role in small molecule drug discovery. In this Account, we outline the relevant methodological advances, including the REST2 (Replica Exchange with Solute Temperting) enhanced sampling, the incorporation of REST2 sampling with convential FEP (Free Energy Perturbation) through FEP/REST, the OPLS3 force field, and the advanced simulation setup that constitute our FEP+ approach, followed by the presentation of extensive comparisons with experiment, demonstrating sufficient accuracy in potency prediction (better than 1 kcal/mol) to substantially impact lead optimization campaigns. The limitations of the current FEP+ implementation and best practices in drug discovery applications are also discussed followed by the future methodology development plans to address those limitations. We then report results from a recent drug discovery project, in which several thousand FEP+ calculations were successfully deployed to simultaneously optimize potency, selectivity, and solubility, illustrating the power of the approach to solve challenging drug design problems. The capabilities of free energy calculations to accurately predict potency and selectivity have led to the advance of ongoing drug discovery projects, in challenging situations where alternative approaches would have great difficulties. The ability to effectively carry out projects evaluating tens of thousands, or hundreds of thousands, of proposed drug candidates

Fracture Capabilities in Grizzly with the extended Finite Element Method (X-FEM)

Energy Technology Data Exchange (ETDEWEB)

Dolbow, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Ziyu [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jiang, Wen [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

Efforts are underway to develop fracture mechanics capabilities in the Grizzly code to enable it to be used to perform deterministic fracture assessments of degraded reactor pressure vessels (RPVs). A capability was previously developed to calculate three-dimensional interaction- integrals to extract mixed-mode stress-intensity factors. This capability requires the use of a finite element mesh that conforms to the crack geometry. The eXtended Finite Element Method (X-FEM) provides a means to represent a crack geometry without explicitly fitting the finite element mesh to it. This is effected by enhancing the element kinematics to represent jump discontinuities at arbitrary locations inside of the element, as well as the incorporation of asymptotic near-tip fields to better capture crack singularities. In this work, use of only the discontinuous enrichment functions was examined to see how accurate stress intensity factors could still be calculated. This report documents the following work to enhance Grizzly’s engineering fracture capabilities by introducing arbitrary jump discontinuities for prescribed crack geometries; X-FEM Mesh Cutting in 3D: to enhance the kinematics of elements that are intersected by arbitrary crack geometries, a mesh cutting algorithm was implemented in Grizzly. The algorithm introduces new virtual nodes and creates partial elements, and then creates a new mesh connectivity; Interaction Integral Modifications: the existing code for evaluating the interaction integral in Grizzly was based on the assumption of a mesh that was fitted to the crack geometry. Modifications were made to allow for the possibility of a crack front that passes arbitrarily through the mesh; and Benchmarking for 3D Fracture: the new capabilities were benchmarked against mixed-mode three-dimensional fracture problems with known analytical solutions.

76 FR 61279 - Defense Federal Acquisition Regulation Supplement; Defense Cargo Riding Gang Member (DFARS Case...

Science.gov (United States)

2011-10-04

... that the language of the proposed clause be amended to read as follows to reinforce DoD's role in the... Military Sealift Command), and specific procedural guidance for DoD personnel obtaining the background... 247.5. B. Language Inconsistency Comment: DFARS 252.247-7027(a) defines ``riding gang member'' as it...

Applying a multi-replication framework to support dynamic situation assessment and predictive capabilities

Science.gov (United States)

Lammers, Craig; McGraw, Robert M.; Steinman, Jeffrey S.

2005-05-01

Technological advances and emerging threats reduce the time between target detection and action to an order of a few minutes. To effectively assist with the decision-making process, C4I decision support tools must quickly and dynamically predict and assess alternative Courses Of Action (COAs) to assist Commanders in anticipating potential outcomes. These capabilities can be provided through the faster-than-real-time predictive simulation of plans that are continuously re-calibrating with the real-time picture. This capability allows decision-makers to assess the effects of re-tasking opportunities, providing the decision-maker with tremendous freedom to make time-critical, mid-course decisions. This paper presents an overview and demonstrates the use of a software infrastructure that supports DSAP capabilities. These DSAP capabilities are demonstrated through the use of a Multi-Replication Framework that supports (1) predictivie simulations using JSAF (Joint Semi-Automated Forces); (2) real-time simulation, also using JSAF, as a state estimation mechanism; and, (3) real-time C4I data updates through TBMCS (Theater Battle Management Core Systems). This infrastructure allows multiple replications of a simulation to be executed simultaneously over a grid faster-than-real-time, calibrated with live data feeds. A cost evaluator mechanism analyzes potential outcomes and prunes simulations that diverge from the real-time picture. In particular, this paper primarily serves to walk a user through the process for using the Multi-Replication Framework providing an enhanced decision aid.

Developing a Dual-Level Capabilities Approach: Using Constructivist Grounded Theory and Feminist Ethnography to Enhance the Capabilities Approaches

Science.gov (United States)

Hall, Kia M. Q.

2014-01-01

In this study, a dual-level capabilities approach to development is introduced. This approach intends to improve upon individual-focused capabilities approaches developed by Amartya Sen and Martha Nussbaum. Based upon seven months of ethnographic research in the Afro-descendant, autochthonous Garifuna community of Honduras, constructivist grounded…

New intelligent multifunctional SiO2/VO2 composite films with enhanced infrared light regulation performance, solar modulation capability, and superhydrophobicity.

Science.gov (United States)

Wang, Chao; Zhao, Li; Liang, Zihui; Dong, Binghai; Wan, Li; Wang, Shimin

2017-01-01

Highly transparent, energy-saving, and superhydrophobic nanostructured SiO 2 /VO 2 composite films have been fabricated using a sol-gel method. These composite films are composed of an underlying infrared (IR)-regulating VO 2 layer and a top protective layer that consists of SiO 2 nanoparticles. Experimental results showed that the composite structure could enhance the IR light regulation performance, solar modulation capability, and hydrophobicity of the pristine VO 2 layer. The transmittance of the composite films in visible region ( T lum ) was higher than 60%, which was sufficient to meet the requirements of glass lighting. Compared with pristine VO 2 films and tungsten-doped VO 2 film, the near IR control capability of the composite films was enhanced by 13.9% and 22.1%, respectively, whereas their solar modulation capability was enhanced by 10.9% and 22.9%, respectively. The water contact angles of the SiO 2 /VO 2 composite films were over 150°, indicating superhydrophobicity. The transparent superhydrophobic surface exhibited a high stability toward illumination as all the films retained their initial superhydrophobicity even after exposure to 365 nm light with an intensity of 160 mW . cm -2 for 10 h. In addition, the films possessed anti-oxidation and anti-acid properties. These characteristics are highly advantageous for intelligent windows or solar cell applications, given that they can provide surfaces with anti-fogging, rainproofing, and self-cleaning effects. Our technique offers a simple and low-cost solution to the development of stable and visible light transparent superhydrophobic surfaces for industrial applications.

Texas hospitals riding tall. While hospitals post robust profit margins, HMOs are saddled with mounting losses.

Science.gov (United States)

Saphir, A

1999-02-08

In Texas, they do things differently, and they do things big. Hospitals in the Lone Star State have been banding together more often and more effectively than elsewhere. Swinging their lassos, they are riding herd on HMOs, enjoying record profits and making ever-larger deals.

The choice of park and ride facilities : an analysis using a context-dependent hierarchical choice experiment

NARCIS (Netherlands)

Bos, D.M.; vd Heijden, R.E.C.M.; Molin, E.J.E.; Timmermans, H.J.P.

2004-01-01

Park and ride (P & R) facilities have been proposed in several countries to alleviate the accessibility problems in cities. Despite growing accessibility problems, these facilities do not seem to attract the expected number of car drivers and are underused. In an attempt to measure consumer

Enhancing the capabilities of eddy current techniques for non-destructive evaluation of austenitic stainless steels

International Nuclear Information System (INIS)

Rao, B.P.C.; Thirunavukkarasu, S.; Sasi, B.; Jayakumar, T.; Baldev Raj

2010-01-01

Eddy current non-destructive evaluation (NDE) techniques find many applications during fabrication and in-service inspection of components made of stainless steel. In recent years, concurrent developments in electromagnetic field detection sensors such as giant magneto-resistive (GMR), giant-magneto impedance (GMI) and SQUIDs sensors, computers, microelectronics, and incorporating advanced signal and image processing techniques, have paved the way for enhancing the capabilities of existing eddy current (EC) techniques for examination of austenitic stainless steel (SS) plates, tubes and other geometries and several innovative methodologies have been developed. This paper highlights a few such applications in EC testing to austenitic stainless steel components used in fast reactors. (author)

Why People Are Not Willing to Let Their Children Ride in Driverless School Buses: A Gender and Nationality Comparison

Directory of Open Access Journals (Sweden)

Emily C. Anania

2018-02-01

Full Text Available As driverless vehicles proliferate, it is possible that this technology will be applied in mass transport vehicles. School buses may be suited for autonomous operations as they follow set routes and schedules. However, a research gap exists in whether or not parents would be willing to have their children ride in autonomously operated school buses. The purpose of this study was to examine parents’ willingness to allow their child to ride in an autonomous school bus. Participant gender and nationality were also two independent variables, along with affect measures as a possible mediating variable. The research used a two-study approach. In study one, it was found that participants were less willing to have their child ride in a driverless school bus than a traditional human-operated vehicle. In study two, findings suggest a significant interaction between the type of driver, participant gender, and nationality. In general, American females were less willing than Indian females and overall, Americans were less willing than Indians in the driverless conditions. Affect was found to be a mediating variable, which suggests that emotions were playing a role in the responses of participants. The paper concludes with theoretical contributions, practical applications, and suggestions for future research.

Operation and Control of a Direct-Driven PMSG-Based Wind Turbine System with an Auxiliary Parallel Grid-Side Converter

Directory of Open Access Journals (Sweden)

Jiawei Chu

2013-07-01

Full Text Available In this paper, based on the similarity, in structure and principle, between a grid-connected converter for a direct-driven permanent magnet synchronous generator (D-PMSG and an active power filter (APF, a new D-PMSG-based wind turbine (WT system configuration that includes not only an auxiliary converter in parallel with the grid-side converter, but also a coordinated control strategy, is proposed to enhance the low voltage ride through (LVRT capability and improve power quality. During normal operation, the main grid-side converter maintains the DC-link voltage constant, whereas the auxiliary grid-side converter functions as an APF with harmonic suppression and reactive power compensation to improve the power quality. During grid faults, a hierarchical coordinated control scheme for the generator-side converter, main grid-side converter and auxiliary grid-side converter, depending on the grid voltage sags, is presented to enhance the LVRT capability of the direct-driven PMSG WT. The feasibility and the effectiveness of the proposed system’s topology and hierarchical coordinated control strategy were verified using MATLAB/Simulink simulations.

Enhanced Transmissions Through Three-dimensional Cascade Sharp Waveguide Bends Using C-slit Diaphragms.

Science.gov (United States)

Yang, Rui; Hu, Bowei; Zhang, Aofang; Gao, Dongxing; Wang, Hui; Shi, Ayuan; Lei, Zhenya; Yang, Pei

2017-03-21

Transmission properties through sharp rectangular waveguide bends are investigated to determine the cut-off bending angles of the wave propagation. We show that a simple metallic diaphragm at the bending corner with properly devised sub-wavelength defect apertures of C-slits would be readily to turn on the transmissions with scarce reflections of the propagating modes, while preserving the integrity of the transmitting fields soon after the bends. In particularly, our design also demonstrates the capability of eliminating all the unwanted cavity resonant transmissions that exist in the three-dimensional cascade sharp waveguide bends, and solely let the desired signals travel along the whole passage of the waveguide. The present approach, using C-slit diaphragms to support the sharp bending behaviors of the guided waves with greatly enhanced transmissions, would be especially effective in constructing novel waveguides and pave the way for the development of more compact and miniaturized electromagnetic systems that exploit these waveguide bends.

[Prevention of injuries associated with horseback riding].

Science.gov (United States)

ten Kate, Chantal A; de Kooter, Tabitha A; Kramer, William L M

2015-01-01

Each year 9,900 equestrians present at Accident and Emergency Departments, 40% of them 10-19 year old females. The most common horse-riding injuries are to the head, brain, neck and face, torso and extremities. Because of the relatively larger head, children more often fall on their head. Wearing a helmet gives considerable protection. Despite the common use of a helmet by horseback riders, serious head injury still occurs regularly. Further research into improvement of the protective function of the helmet is indicated. The current safety vest (body protector) does not significantly reduce the risk of torso injury. Improvement of its protective function is necessary. Injury to the lower extremities is caused when they become trapped in the stirrup in a fall from or with the horse. Safety stirrups and sturdy footwear are possible preventive measures. Investment in the quality and promotion of preventive measures could reduce the frequency and severity of equestrian injuries.

Enhancement of Pre-and Post-Processing Capability of the CUPID code

Energy Technology Data Exchange (ETDEWEB)

Kim, Jongtae; Park, Ik Kyu; Yoon, Hanyoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

To simulate heat transfer and fluid flow in a field with a complicated geometry, an unstructured mesh is popularly used. Most commercial CFD (Computational Fluid Dynamics) solvers are based on an unstructured mesh technology. An advantage of using unstructured meshes for a field simulation is reduced man-hours by automatic mesh generation compared to a traditional structured mesh generation, which requires a huge amount of man-hours to discretized a complex geometry. Initially, unstructured meshes that can be generated automatically are limited to regular cell elements such as tetrahedron, pyramid, prism, or hexahedron. The multi-dimensional multi-phase flow solver, CUPID, has been developed in the context of an unstructured mesh finite volume method (FVM). Its numerical formulation and programming structure is independent of the number of faces surrounding the computational cells. Thus, it can be easily extended into polyhedral unstructured meshes. In this study, new tools for enhancing the pre- and post-processing capabilities of CUPID are proposed. They are based on an open-source CFD tool box OpenFOAM. A goal of this study is an extension of the applicability of the CUPID code by improving the mesh and solution treatment of the code.

Increasing Road Infrastructure Capacity Through the Use of Autonomous Vehicles

Science.gov (United States)

2016-12-01

considerably in recent years. In many urban areas, individuals have foregone purchasing vehicles and have instead joined car - sharing programs like...lots throughout the metropolitan area.107 Car sharing has expanded to include bike-sharing programs like Capital Bikeshare in Washington, DC.108...vehicles could also enhance ride-sharing and car - sharing services, in which a user could request a vehicle via a mobile device to drive directly to the

Overexpression of Insulin-Like Growth Factor 1 Enhanced the Osteogenic Capability of Aging Bone Marrow Mesenchymal Stem Cells.

Science.gov (United States)

Chen, Ching-Yun; Tseng, Kuo-Yun; Lai, Yen-Liang; Chen, Yo-Shen; Lin, Feng-Huei; Lin, Shankung

2017-01-01

Many studies have indicated that loss of the osteoblastogenic potential in bone marrow mesenchymal stem cells (bmMSCs) is the major component in the etiology of the aging-related bone deficit. But how the bmMSCs lose osteogenic capability in aging is unclear. Using 2-dimentional cultures, we examined the dose response of human bmMSCs, isolated from adult and aged donors, to exogenous insulin-like growth factor 1 (IGF-1), a growth factor regulating bone formation. The data showed that the mitogenic activity and the osteoblastogenic potential of bmMSCs in response to IGF-1 were impaired with aging, whereas higher doses of IGF-1 increased the proliferation rate and osteogenic potential of aging bmMSCs. Subsequently, we seeded IGF-1-overexpressing aging bmMSCs into calcium-alginate scaffolds and incubated in a bioreactor with constant perfusion for varying time periods to examine the effect of IGF-1 overexpression to the bone-forming capability of aging bmMSCs. We found that IGF-1 overexpression in aging bmMSCs facilitated the formation of cell clusters in scaffolds, increased the cell survival inside the cell clusters, induced the expression of osteoblast markers, and enhanced the biomineralization of cell clusters. These results indicated that IGF-1 overexpression enhanced cells' osteogenic capability. Thus, our data suggest that the aging-related loss of osteogenic potential in bmMSCs can be attributed in part to the impairment in bmMSCs' IGF-1 signaling, and support possible application of IGF-1-overexpressing autologous bmMSCs in repairing bone defect of the elderly and in producing bone graft materials for repairing large scale bone injury in the elderly.

Doubly-Fed Induction Generator Control Under Voltage Sags

DEFF Research Database (Denmark)

Teodorescu, Remus; Blaabjerg, Frede; Lima, K.

2008-01-01

This paper proposes a new control technique to improve the fault-ride through capability of doubly fed induction generators (DFIG). In such generators the appearance of severe voltage sags at the coupling point make rise to high over currents at the rotor/stator windings, something that makes...

Integrating stochastic time-dependent travel speed in solution methods for the dynamic dial-a-ride problem.

Science.gov (United States)

Schilde, M; Doerner, K F; Hartl, R F

2014-10-01

In urban areas, logistic transportation operations often run into problems because travel speeds change, depending on the current traffic situation. If not accounted for, time-dependent and stochastic travel speeds frequently lead to missed time windows and thus poorer service. Especially in the case of passenger transportation, it often leads to excessive passenger ride times as well. Therefore, time-dependent and stochastic influences on travel speeds are relevant for finding feasible and reliable solutions. This study considers the effect of exploiting statistical information available about historical accidents, using stochastic solution approaches for the dynamic dial-a-ride problem (dynamic DARP). The authors propose two pairs of metaheuristic solution approaches, each consisting of a deterministic method (average time-dependent travel speeds for planning) and its corresponding stochastic version (exploiting stochastic information while planning). The results, using test instances with up to 762 requests based on a real-world road network, show that in certain conditions, exploiting stochastic information about travel speeds leads to significant improvements over deterministic approaches.

Compression fractures of the vertebrae during a "bumpy" boat ride.

LENUS (Irish Health Repository)

Chukwunyerenwa, C K

2012-01-31

INTRODUCTION: Compression fracture of the vertebrae is common, often the result of falls from height and motor vehicle accidents in the younger age groups. It can occur following minor trauma in the elderly and in those with osteoporosis. MATERIALS AND METHODS: We present an interesting case of compression fracture of the vertebral bodies occurring simultaneously in a couple during a boat ride while on holiday. One individual had fracture of the T8, while the other fractured the L1 vertebrae. Both injuries were treated conservatively with Taylor braces. CONCLUSION: We highlight one of the potential hazards of this recreational activity, and the almost identical fracture pattern in this couple.

Deep Seawater Intrusion Enhanced by Geothermal Through Deep Faults in Xinzhou Geothermal Field in Guangdong, China

Science.gov (United States)

Lu, G.; Ou, H.; Hu, B. X.; Wang, X.

2017-12-01

This study investigates abnormal sea water intrusion from deep depth, riding an inland-ward deep groundwater flow, which is enhanced by deep faults and geothermal processes. The study site Xinzhou geothermal field is 20 km from the coast line. It is in southern China's Guangdong coast, a part of China's long coastal geothermal belt. The geothermal water is salty, having fueled an speculation that it was ancient sea water retained. However, the perpetual "pumping" of the self-flowing outflow of geothermal waters might alter the deep underground flow to favor large-scale or long distant sea water intrusion. We studied geochemical characteristics of the geothermal water and found it as a mixture of the sea water with rain water or pore water, with no indication of dilution involved. And we conducted numerical studies of the buoyancy-driven geothermal flow in the deep ground and find that deep down in thousand meters there is favorable hydraulic gradient favoring inland-ward groundwater flow, allowing seawater intrude inland for an unusually long tens of kilometers in a granitic groundwater flow system. This work formed the first in understanding geo-environment for deep ground water flow.

Enhancing state-community relations through the ward development ...

African Journals Online (AJOL)

The primary responsibility of the government is to develop communities under its jurisdiction through community development projects. The development of the rural areas creates conditions conducive for community living, enhances the legitimacy of government and promotes state-community relations. But the political ...

Co-ordinated voltage control of DFIG wind turbines in uninterrupted operation during grid faults

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Michalke, G.; Sørensen, Poul Ejnar

2007-01-01

Emphasis in this article is on the design of a co-ordinated voltage control strategy for doubly fed induction generator (DFIG) wind turbines that enhances their capability to provide grid support during grid faults. In contrast to its very good performance in normal operation, the DFIG wind turbine...... concept is quite sensitive to grid faults and requires special power converter protection. The fault ride-through and grid support capabilities of the DFIG address therefore primarily the design of DFIG wind turbine control with special focus on power converter protection and voltage control issues....... A voltage control strategy is designed and implemented in this article, based on the idea that both converters of the DFIG (i.e. rotor-side converter and grid-side converter) participate in the grid voltage control in a co-ordinated manner. By default the grid voltage is controlled by the rotor...

Enhanced Critical Thinking Skills through Problem-Solving Games in Secondary Schools

OpenAIRE

Scott D McDonald

2017-01-01

Aim/Purpose: Students face many challenges improving their soft skills such as critical thinking. This paper offers one possible solution to this problem. Background: This paper considers one method of enhancing critical thinking through a problem-solving game called the Coffee Shop. Problem-solving is a key component to critical thinking, and game-playing is one method of enhancing this through an interactive teaching method. Methodology: Three classes of Vietnamese high school stude...

Capability through Participatory Democracy: Sen, Freire, and Dewey

Science.gov (United States)

Glassman, Michael; Patton, Rikki

2014-01-01

This paper explores possible important relationships and sympathies between Amartya Sen's Capabilities Approach framework for understanding the human condition and the educational ideas of John Dewey and Paolo Freire. All three focus on the importance of democratic values in a fair, well-functioning society, while Sen and Freire especially…

Rapid emergence of free-riding behavior in new pediatric immunization programs.

Directory of Open Access Journals (Sweden)

Chris T Bauch

Full Text Available BACKGROUND: Mathematical models have formalized how free-rider effects can threaten the stability of high vaccine coverage levels under established voluntary vaccination programs. However, little research has addressed the question of when free-riding begins to develop when a new vaccine is first introduced in a population. METHODOLOGY/PRINCIPAL FINDINGS: Here, we combine a game theoretical model of vaccinating behavior with an age-structured compartmental model to analyze rational vaccinating behavior in the first years of a universal immunization program, where a new vaccine is free to all children of a specified age. The model captures how successive birth cohorts face different epidemiological landscapes that have been shaped by the vaccinating decisions of previous birth cohorts, resulting in a strategic interaction between individuals in different birth cohorts. The model predicts a Nash equilibrium coverage level of for the first few birth cohorts under the new program. However, free-riding behavior emerges very quickly, with the Nash equilibrium vaccine coverage dropping significantly within 2-5 years after program initiation. Subsequently, a rich set of coupled dynamics between infection prevalence and vaccinating behaviors is possible, ranging from relatively stable (but reduced coverage in later birth cohorts to wide fluctuations in vaccine coverage from one birth cohort to the next. Individual tolerance for vaccine risk also starts out at relatively high levels before dropping significantly within a few years. CONCLUSIONS/SIGNIFICANCE: These results suggest that even relatively new immunization programs can be vulnerable to drops in vaccine coverage caused by vaccine scares and exacerbated by herd immunity effects, necessitating vigilance from the start.

Thermal Behavior of Doubly-Fed Induction Generator Wind Turbine System during Balanced Grid Fault

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Lau, Mogens

2014-01-01

Ride-through capabilities of the doubly-fed induction generator (DFIG) during grid fault have been studied a lot. However, the thermal performance of the power device during this transient period is seldom investigated. In this paper, the dynamic model for the DFIG and the influence of the rotor...

ReRide

DEFF Research Database (Denmark)

Bagalkot, Naveen; Sokoler, Tomas; Shaikh, Riyaj

2017-01-01

-situ evaluation of such tools. We present the system architecture and demonstrate the capabilities of the system by presenting a case instantiation in the form of an interactive soft-and-hardware prototype that collects rider’s posture data,visualizes the data on the motorbike dashboard in real-time, and pushes...

The Advanced Modeling, Simulation and Analysis Capability Roadmap Vision for Engineering

Science.gov (United States)

Zang, Thomas; Lieber, Mike; Norton, Charles; Fucik, Karen

2006-01-01

This paper summarizes a subset of the Advanced Modeling Simulation and Analysis (AMSA) Capability Roadmap that was developed for NASA in 2005. The AMSA Capability Roadmap Team was chartered to "To identify what is needed to enhance NASA's capabilities to produce leading-edge exploration and science missions by improving engineering system development, operations, and science understanding through broad application of advanced modeling, simulation and analysis techniques." The AMSA roadmap stressed the need for integration, not just within the science, engineering and operations domains themselves, but also across these domains. Here we discuss the roadmap element pertaining to integration within the engineering domain, with a particular focus on implications for future observatory missions. The AMSA products supporting the system engineering function are mission information, bounds on information quality, and system validation guidance. The Engineering roadmap element contains 5 sub-elements: (1) Large-Scale Systems Models, (2) Anomalous Behavior Models, (3) advanced Uncertainty Models, (4) Virtual Testing Models, and (5) space-based Robotics Manufacture and Servicing Models.

Using Porterian Activity Analysis to Understand Organizational Capabilities

DEFF Research Database (Denmark)

Sheehan, Norman T.; Foss, Nicolai Juul

2017-01-01

conceptualized by Porter’s writings on the activity-based view. Porterian activity analysis is becoming more accepted in the strategy literature, but no strategy scholar has explicitly used Porter’s activities, and particularly his concept of drivers, to understand and analyze organizational capabilities....... Introducing Porterian activities into the discussion of capabilities improves strategy scholars’ understanding of the bases of capability heterogeneity, offers academics future directions for research, and provides managers with guidance to enhance their organizations’ capabilities....

UV plasmonic enhancement through three dimensional nano-cavity antenna array in aluminum

Science.gov (United States)

Mao, Jieying; Stevenson, Peter; Montanaric, Danielle; Wang, Yunshan; Shumaker-Parry, Jennifer S.; Harris, Joel M.; Blair, Steve

2017-08-01

Metallic nanostructure can enhance fluorescence through excited surface plasmons which increase the local field as well as improve its quantum efficiency. When coupling to cavity resonance with proper gap dimension, gap hot spots can be generated to interact with fluorescence at their excitation/emission region in UV. A 3D nano-cavity antenna array in Aluminum has been conducted to generate local hot spot resonant at fluorescence emission resonance. Giant field enhancement has been achieved through coupling fundamental resonance modes of nanocavity into surface plasmons polaritons (SPPs). In this work, two distinct plasmonic structure of 3D resonant cavity nanoantenna has been studied and its plasmonic response has been scaled down to the UV regime through finite-difference-time-domain (FDTD) method. Two different strategies for antenna fabrication will be conducted to obtain D-coupled Dots-on-Pillar Antenna array (D2PA) through Focus Ion Beam (FIB) and Cap- Hole Pair Antenna array (CHPA) through nanosphere template lithography (NTL). With proper optimization of the structures, D2PA and CHPA square array with 280nm pitch have achieved distinct enhancement at fluorophore emission wavelength 350nm and excitation wavelength 280nm simultaneously. Maximum field enhancement can reach 20 and 65 fold in the gap of D2PA and CHPA when light incident from substrate, which is expected to greatly enhance fluorescent quantum efficiency that will be confirmed in fluorescence lifetime measurement.

Come on and take a free ride : Contributing to public goods in native and foreign language settings

NARCIS (Netherlands)

Urbig, Diemo; Terjesen, Siri; Procher, Vivien; Muehlfeld, Katrin; Van Witteloostuijn, Arjen

2016-01-01

Business schools around the world must prepare their students for two realities: operating in an English-speaking business world and working in teams. As yet, there is limited understanding of how operating in a native or a foreign language impacts students' propensity to free ride in group

Come on and take a free ride : Contributing to public goods in native and foreign language settings

NARCIS (Netherlands)

Urbig, D.; Terjesen, S.; Procher, V.; Muhlfeld, K.S.; van Witteloostuijn, A.

Business schools around the world must prepare their students for two realities: operating in an English-speaking business world and working in teams. As yet, there is limited understanding of how operating in a native or a foreign language impacts students' propensity to free ride in group

A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

DEFF Research Database (Denmark)

Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

2015-01-01

This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VSC......-HVDC) converter station. Due to limited short circuit power contribution from power electronic interfaced variable speed wind generators and with the onshore main grid decoupled by the HVDC link, the offshore AC grid becomes more vulnerable to dynamic voltage events. Therefore, a short circuit fault...... in the offshore AC Grid is likely to have significant implications on the voltage of the offshore AC grid, hence on the power flow to the onshore mainland grid. The proposed CVCS integrates individual local reactive power control of wind turbines and of the HVDC converter with the secondary voltage controller...

How much can you drink before driving? The influence of riding with impaired adults and peers on the driving behaviors of urban and rural youth.

Science.gov (United States)

Leadbeater, Bonnie J; Foran, Kathleen; Grove-White, Aidan

2008-04-01

Following an ecological model to specify risks for impaired driving, we assessed the effects of youth attitudes about substance use and their experiences of riding in cars with adults and peers who drove after drinking alcohol or smoking cannabis on the youths' own driving after drinking or using cannabis. Participants were 2594 students in grades 10 and 12 (mean age = 16 years and 2 months; 50% girls) from public high schools in urban (994) and rural communities (1600) on Vancouver Island in British Columbia, Canada; 1192 of these were new drivers with restricted licenses. Self-report data were collected in anonymous questionnaires. Regression analyses were used to assess the independent and interacting effects of youth attitudes about substance use and their experiences of riding in cars with adults or peers who drove after drinking alcohol or smoking cannabis on youth driving. Youth driving risk behaviors were associated independently with their own high-risk attitudes and experiences riding with peers who drink alcohol or use cannabis and drive. However, risks were highest for the youth who also report more frequent experiences of riding with adults who drink alcohol or use cannabis and drive. Prevention efforts should be expanded to include the adults and peers who are role models for new drivers and to increase youths' awareness of their own responsibilities for their personal safety as passengers.

Rotor Voltage Dynamics in the Doubly Fed Induction Generator During Grid Faults

DEFF Research Database (Denmark)

Lima, Francisco K. A.; Luna, Alvaro; Rodriguez, Pedro

2010-01-01

This paper presents a new control strategy for the rotor-side converter (RSC) of wind turbines (WTs) based on doubly fed induction generators (DFIG) that intends to improve its low-voltage ride through capability. The main objective of this work is to design an algorithm that would enable the sys...

Comprehensive Reactive Power Support of DFIG Adapted to Different Depth of Voltage Sags

Directory of Open Access Journals (Sweden)

Yangwu Shen

2017-06-01

Full Text Available The low voltage ride-through (LVRT capability of the doubly-fed induction generator (DFIG significantly impacts upon the integration of wind power into the power grid. This paper develops a novel comprehensive control strategy to enhance the LVRT and reactive power support capacities of the DFIG by installing the energy storage system (ESS. The ESS is connected to the DC-link capacitor of the DFIG and used to regulate the DC-link voltage during normal or fault operations. The unbalanced power between the captured wind power and the power injected to the grid during the transient process is absorbed or compensated by the ESS. The rotor-side converter (RSC is used to control the maximum power production and the grid-side converter (GSC is used to control the reactive power before participating in the voltage support. When the supply voltage continues to drop, the rotor speed is increased by controlling the RSC to realize the LVRT capability and help the GSC further enhance the reactive power support capability. The capacity of the GSC is dedicated to injecting the reactive power to the grid. An auxiliary transient pitch angle controller is proposed to protect the generator’s over speed. Both RSC and GSC act as reactive power sources to further enhance the voltage support capability with serious voltage sags. Simulations based on a single-machine infinite-bus power system verify the effectiveness of the developed comprehensive control strategy.

Enhancing Nurses Access for Care Quality and Knowledge through ...

International Development Research Centre (IDRC) Digital Library (Canada)

Enhancing Nurses Access for Care Quality and Knowledge through ... Special journal issue highlights IDRC-supported findings on women's paid work ... New website will help record vital life events to improve access to services for all.

Enhancing healthy ageing through music | Ekong | UJAH: Unizik ...

African Journals Online (AJOL)

UJAH: Unizik Journal of Arts and Humanities. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 16, No 2 (2015) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Enhancing healthy ageing through music.

Long-term bicycle riding ameliorates the depression of the patients undergoing hemodialysis by affecting the levels of interleukin-6 and interleukin-18

Directory of Open Access Journals (Sweden)

Zhao C

2016-12-01

Full Text Available Chunhui Zhao, Hui Ma, Lei Yang, Yong Xiao Blood Purification Center, The First Affiliated Hospital of Dalian Medical University, Dalian, People’s Republic of China Purpose: Hemodialysis patients with depression have a higher risk of death and hospitalization. Although there is pharmacological management for the depression of hemodialysis patients, the adverse effect of the drug limits the use. The nonpharmacological way, bicycle riding, may be an effective way for the therapy of the depression in hemodialysis patients. However, the underlying mechanism of this relationship is still not fully explained, while interleukin-6 (IL-6 and interleukin-18 (IL-18 are associated with depression and exercise. Thus, the effects of bicycle riding on the levels of the interleukin were explored. Participants and methods: One hundred and eighty-nine patients with chronic hemodialysis were selected and randomly assigned to three groups of medicine (MG, received 20-mg escitalopram daily, medicine and aerobic exercise (MAG, received 20-mg escitalopram daily and bicycle riding six times weekly, and only aerobic exercise (AG, received 20-mg placebo daily and bicycle riding six times weekly. The whole experiment lasted for 18 weeks. The quality of life (36-Item Short Form Health Survey and depression severity according to criteria in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition [DSM-IV] were measured before and at the end of this study. The serum levels of IL-6 and IL-18 were measured by an enzyme-linked immunosorbent assay kit. Results: The quality of life was improved and depression severity was reduced significantly in the MAG and AG groups when compared with the MG group (P<0.05. Serum levels of IL-6 and IL-18 were the highest in the MG group, moderate in the MAG group and the lowest in AG group. On the other hand, the serum levels of IL-6 and IL-18 were closely associated with depression scores (P<0.05. Conclusion: Aerobic exercise

Modelling and control of variable speed wind turbines for power system studies

DEFF Research Database (Denmark)

Michalke, Gabriele; Hansen, Anca Daniela

2010-01-01

and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride-through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally......, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride-through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.......Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed...

Application of Boost Converter for Ride-through Capability of Adjustable Speed Drives during Sag and Swell Conditions

OpenAIRE

S. S. Deswal; Ratna Dahiya; D. K. Jain

2008-01-01

Process control and energy conservation are the two primary reasons for using an adjustable speed drive. However, voltage sags are the most important power quality problems facing many commercial and industrial customers. The development of boost converters has raised much excitement and speculation throughout the electric industry. Now utilities are looking to these devices for performance improvement and reliability in a variety of areas. Examples of these include sags,...

Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

DEFF Research Database (Denmark)

Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

2013-01-01

Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-so......-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

Effects of the Horse Riding Simulator and Ball Exercises on Balance of the Elderly

Science.gov (United States)

Kim, SeongGil; Yuk, Goon-chang; Gak, Hwangbo

2013-01-01

[Purpose] The aim of this study was to examine the effects of horse riding exercise using a horse riding simulator (HRS) and a ball on static and dynamic balance of elderly people. [Methods] Thirty-two elderly people hospitalized in geriatric hospitals were randomly assigned to the HRS exercise group or the ball exercise groups, and they performed exercise for eight weeks. [Results] The length of postural sway during quite standing with and without eyes closed significantly decreased in both groups after the exercises and there was no significant difference between both groups in the Romberg test. In the functional reach test (FRT), there were significant increases in distance in both groups after the exercises, and the distance of the HRS exercise group was significantly greater than that of the ball exercise group. In the Timed Up & Go test (TUG) and Timed 10-meter walk test (10MWT), the time significantly decreased in both groups, and there was a more significant decrease in the HRS exercise group than in the ball exercise group. [Conclusion] The results of this study indicate that HRS and ball exercises may improve the balance and gait ability of elderly people hospitalized in nursing homes or geriatric hospitals. PMID:24396203

On the temperature dependence of H-U{sub iso} in the riding hydrogen model

Energy Technology Data Exchange (ETDEWEB)

Lübben, Jens; Volkmann, Christian [Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany); Grabowsky, Simon [School of Chemistry and Biochemistry, Stirling Highway 35, WA-6009 Crawley (Australia); Edwards, Alison [Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Morgenroth, Wolfgang [Institut für Geowissenschaften, Abteilung Kristallographie, Goethe-Universität, Altenhöferallee 1, 60438 Frankfurt am Main (Germany); Fabbiani, Francesca P. A. [GZG, Abteilung Kristallographie, Georg-August Universität, Goldschmidtstrasse 1, 37077 Göttingen (Germany); Sheldrick, George M. [Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany); Dittrich, Birger, E-mail: birger.dittrich@chemie.uni-hamburg.de [Institut für Anorganische und Angewandte Chemie, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany)

2014-07-01

The temperature dependence of hydrogen U{sub iso} and parent U{sub eq} in the riding hydrogen model is investigated by neutron diffraction, aspherical-atom refinements and QM/MM and MO/MO cluster calculations. Fixed values of 1.2 or 1.5 appear to be underestimated, especially at temperatures below 100 K. The temperature dependence of H-U{sub iso} in N-acetyl-l-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U{sub iso} below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffraction data to high resolution, collected at temperatures of 9, 30, 50, 75, 100, 150, 200 and 250 K (synchrotron and home source), reproduce neutron results only when evaluated by aspherical-atom refinement models, since these take into account bonding and lone-pair electron density; both invariom and Hirshfeld-atom refinement models enable a more precise determination of the magnitude of H-atom displacements than independent-atom model refinements. Experimental efforts are complemented by computing displacement parameters following the TLS+ONIOM approach. A satisfactory agreement between all approaches is found.

Enhancement techniques for improving 5-aminolevulinic acid delivery through the skin

Directory of Open Access Journals (Sweden)

Li-Wen Zhang

2011-03-01

Full Text Available Photodynamic therapy (PDT is a popular technique for skin cancer treatment. Protoporphyrin IX, which is a photosensitizing agent, converted enzymatically from the prodrug 5-aminolevulinic acid (ALA, is used as a photosensitizer in PDT for cancer. However, ALA penetrates with difficulty through intact skin; therefore, improving delivery systems for ALA in the skin will play an important role in ALA-PDT. Enhancement of ALA skin penetration can be achieved by physical methods, such as iontophoresis, laser, microneedles, ultrasound, and by adding chemical penetration enhancers, such as, dimethyl sulfoxide, oleic acid, and others, whereas some researches used lipophilic ALA derivatives and different vehicles to improve the transdermal delivery of ALA. This review introduces several enhancement techniques for increasing ALA permeation through the skin.

The Virtual Resistance Control Strategy for HVRT of Doubly Fed Induction Wind Generators Based on Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Zhen Xie

2014-01-01

Full Text Available Grid voltage swell will cause transient DC flux component in the doubly fed induction generator (DFIG stator windings, creating serious stator and rotor current and torque oscillation, which is more serious than influence of the voltage dip. It is found that virtual resistance manages effectively to suppress rotor current and torque oscillation, avoid the operation of crowbar circuit, and enhance its high voltage ride through technology capability. In order to acquire the best virtual resistance value, the excellent particle library (EPL of dynamic particle swarm optimization (PSO algorithm is proposed. It takes the rotor voltage and rotor current as two objectives, which has a fast convergence performance and high accuracy. Simulation and experimental results verify the effectiveness of the virtual resistance control strategy.

Assistive technology use is associated with reduced capability poverty: a cross-sectional study in Bangladesh.

Science.gov (United States)

Borg, Johan; Ostergren, Per-Olof; Larsson, Stig; Rahman, Asm Atiqur; Bari, Nazmul; Khan, Ahm Noman

2012-03-01

About half of all people with disabilities in developing countries live in extreme poverty. Focusing on the ends rather than the economic means of human development, the capability approach offers an alternative view of poverty. The purpose of this study was to explore the relation between assistive technology use and capability poverty in a low-income country. Self-reported data on food intake, health care, education, politics, self-determination, self-respect, family relationships and friendships were collected in Bangladesh through interviews of people with hearing impairments using and not using hearings aids, and people with ambulatory impairments using and not using manual wheelchairs (N = 583). Differences in outcomes between users and non-users of assistive technology were analyzed using logistic regression. Assistive technology users were more likely than non-users to report enhanced capabilities, hearing aid users to a larger extent than wheelchair users. Synergistic effects between assistive technology use and education were found. The use of assistive technology is predictive of reduced capability poverty in Bangladesh. Lack of wheelchair accessibility and the nature of selected outcomes may explain the limited association in the ambulatory group. Enhancing the effects of the other, there is support for providing education in combination with hearing aids. [Box: see text].

Facility Interface Capability Assessment (FICA) project report

International Nuclear Information System (INIS)

Pope, R.B.; MacDonald, R.R.; Viebrock, J.M.; Mote, N.

1995-09-01

The US Department of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is responsible for developing the Civilian Radioactive Waste Management System (CRWMS) to accept spent nuclear fuel from commercial facilities. The objective of the Facility Interface Capability Assessment (FICA) project was to assess the capability of each commercial spent nuclear fuel (SNF) storage facility, at which SNF is stored, to handle various SNF shipping casks. The purpose of this report is to present and analyze the results of the facility assessments completed within the FICA project. During Phase 1, the data items required to complete the facility assessments were identified and the database for the project was created. During Phase 2, visits were made to 122 facilities on 76 sites to collect data and information, the database was updated, and assessments of the cask-handling capabilities at each facility were performed. Each assessment of cask-handling capability contains three parts: the current capability of the facility (planning base); the potential enhanced capability if revisions were made to the facility licensing and/or administrative controls; and the potential enhanced capability if limited physical modifications were made to the facility. The main conclusion derived from the planning base assessments is that the current facility capabilities will not allow handling of any of the FICA Casks at 49 of the 122 facilities evaluated. However, consideration of potential revisions and/or modifications showed that all but one of the 49 facilities could be adapted to handle at least one of the FICA Casks. For this to be possible, facility licensing, administrative controls, and/or physical aspects of the facility would need to be modified

Facility Interface Capability Assessment (FICA) project report

Energy Technology Data Exchange (ETDEWEB)

Pope, R.B. [ed.] [Oak Ridge National Lab., TN (United States); MacDonald, R.R. [ed.] [Civilian Radioactive Waste Management System, Vienna, VA (United States); Viebrock, J.M.; Mote, N. [Nuclear Assurance Corp., Norcross, GA (United States)

1995-09-01

The US Department of Energy`s (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is responsible for developing the Civilian Radioactive Waste Management System (CRWMS) to accept spent nuclear fuel from commercial facilities. The objective of the Facility Interface Capability Assessment (FICA) project was to assess the capability of each commercial spent nuclear fuel (SNF) storage facility, at which SNF is stored, to handle various SNF shipping casks. The purpose of this report is to present and analyze the results of the facility assessments completed within the FICA project. During Phase 1, the data items required to complete the facility assessments were identified and the database for the project was created. During Phase 2, visits were made to 122 facilities on 76 sites to collect data and information, the database was updated, and assessments of the cask-handling capabilities at each facility were performed. Each assessment of cask-handling capability contains three parts: the current capability of the facility (planning base); the potential enhanced capability if revisions were made to the facility licensing and/or administrative controls; and the potential enhanced capability if limited physical modifications were made to the facility. The main conclusion derived from the planning base assessments is that the current facility capabilities will not allow handling of any of the FICA Casks at 49 of the 122 facilities evaluated. However, consideration of potential revisions and/or modifications showed that all but one of the 49 facilities could be adapted to handle at least one of the FICA Casks. For this to be possible, facility licensing, administrative controls, and/or physical aspects of the facility would need to be modified.

Co-evolution of three mega-trends nurtures un-captured GDP : Uber's ride-sharing revolution

OpenAIRE

Watanabe, Chihiro; Naveed, Kashif; Neittaanmäki, Pekka

2016-01-01

Uber used a disruptive business model driven by digital technology to trigger a ride-sharing revolution. The institution- al sources of the company’s platform ecosystem architecture were analyzed to explain this revolutionary change. Both an empirical analysis of a co-existing development trajectory with taxis and institutional enablers that helped to create Uber’s platform ecosystem were analyzed. The analysis identified a correspondence with the “two-faced” nature of ICT that nu...

Campus Capability Plan

Energy Technology Data Exchange (ETDEWEB)

Adams, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arsenlis, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bailey, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brase, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brenner, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Camara, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carlton, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cheng, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chrzanowski, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Colson, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); East, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Farrell, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferranti, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gursahani, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hansen, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Helms, L. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hernandez, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jeffries, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Larson, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lu, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McNabb, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mercer, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Skeate, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sueksdorf, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zucca, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Le, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ancria, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scott, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Leininger, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gagliardi, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gash, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bronson, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chung, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hobson, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Meeker, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanchez, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zagar, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Quivey, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sommer, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Atherton, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-06-06

Lawrence Livermore National Laboratory Campus Capability Plan for 2018-2028. Lawrence Livermore National Laboratory (LLNL) is one of three national laboratories that are part of the National Nuclear Security Administration. LLNL provides critical expertise to strengthen U.S. security through development and application of world-class science and technology that: Ensures the safety, reliability, and performance of the U.S. nuclear weapons stockpile; Promotes international nuclear safety and nonproliferation; Reduces global danger from weapons of mass destruction; Supports U.S. leadership in science and technology. Essential to the execution and continued advancement of these mission areas are responsive infrastructure capabilities. This report showcases each LLNL capability area and describes the mission, science, and technology efforts enabled by LLNL infrastructure, as well as future infrastructure plans.

Effect of therapeutic horseback riding on balance in community-dwelling older adults with balance deficits.

Science.gov (United States)

Homnick, Douglas N; Henning, Kim M; Swain, Charlene V; Homnick, Tamara D

2013-07-01

Falls are an important cause of morbidity in older adults. Equine-assisted activities including therapeutic riding (TR) benefit balance and neuromuscular control in patients with neurological disabilities but have not been systematically studied in older adults at greater risk for falls due to balance deficits. The effect of an 8-week TR program on measures of balance and quality of life in community-dwelling older adults with established balance deficits was evaluated. This was a pretest-post-test single-group trial of a TR program on measures of balance and quality of life. The study was conducted at a Professional Association of Therapeutic Horsemanship (PATH) International Premier riding center. The subjects comprised 9 adults (5 female, 4 males) with a mean age 76.4 years (range 71-83 years). This included an 8-week observation period followed by an 8-week TR program consisting of 1 hour per week of supervised horseback riding and an 8-week follow-up period. SUBJECTS received balance testing at weeks 0, 8, 16, and 24 using the Fullerton Advanced Balance Scale (FABS), and quality of life was measured at weeks 8 and 16 using the Rand SF (short form) 36 quality-of-life measure. OUTCOME MEASURES were change in the FABS and Rand SF 36. There was no significant difference in balance scores between the start and end of the observation period. There was a significant improvement in the balance score and perception of general health from the start to the end of the intervention period, and no significant difference between the end of the intervention and the end of study, suggesting that improvements may have been sustained. TR is a safe activity for older adults with mild to moderate balance deficits and leads to both improvements in balance and quality of life. Longer and larger studies to assess the benefit of equine-assisted activities on improvements in balance and reduction in fall risk are needed.

Improving Design Understandings and Skills through Enhanced Metacognition: Reflective Design Journals

Science.gov (United States)

Kurt, Mustafa; Kurt, Sevinc

2017-01-01

The main aim of this study was to investigate and discover whether going through the process of reflection by keeping reflective design journals (RDJ) enhances architecture students' metacognition and whether this enhanced metacognition improves their design understandings and skills. The study was a mixed-methods design and utilised content…

Satellite-based Tropical Cyclone Monitoring Capabilities

Science.gov (United States)

Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.

2012-12-01

Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.

Aktsiaseltsi aktsionäride, asutajate, juhatuse ja nõukogu liikmete vastutus : [bakalaureusetöö] / Kristi Relvik ; Õigusinstituut ; juhendaja: Kilvar Kessler

Index Scriptorium Estoniae

Relvik, Kristi

1998-01-01

Aktsionäride vastutus, asutajate vastutus, juhatuse ja liikmete vastutus.Vt. ka Relvik, Kristi. Aktsiaseltsi juhatuse ja nõukogu liikmete vastutus // Õigusinstituudi toimetised (1998) nr. 1, lk. 12

Riding the waves of culture understanding cultural diversity in business

CERN Document Server

Trompenaars, Fons

1993-01-01

The definitive guide to cross-cultural management--updated to help you lead effectively during a time of unprecedented globalization First published nearly 20 years ago, Riding the Waves of Culture became the standard guide to conducting business in an international context. Now, the third edition provides you with important new information and groundbreaking methods for leading effectively in the most globalized business landscape ever. Fons Trompenaars is a world expert on international management and founder and director of Trompenaars Hampden-Turner (THT), a consulting firm in the field of intercultural management. Charles Hampden-Turner is a Senior Research Associate at the Judge Business School at the University of Cambridge and cofounder and Director of Research and Development at the Trompenaars-Hampden-Turner Group.

Comparison of capability of dynamic O2-enhanced MRI and quantitative thin-section MDCT to assess COPD in smokers

International Nuclear Information System (INIS)

Ohno, Yoshiharu; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Keiko; Aoyama, Nobukazu; Onishi, Yumiko; Takenaka, Daisuke; Matsumoto, Sumiaki; Nishimura, Yoshihiro; Sugimura, Kazuro

2012-01-01

Purpose: The purpose of this study was to directly and prospectively compare the capability of dynamic O 2 -enhanced MRI and quantitatively assessed thin-section MDCT to assess smokers’ COPD in a large prospective cohort. Materials and methods: The GOLD criteria for smokers were used to classify 187 smokers into four clinical stage groups as follows: smokers without COPD (n = 56) and with mild (n = 54), moderate (n = 52) and severe or very severe COPD (n = 24). All smokers underwent dynamic O 2 -enhanced MRI, MDCT and pulmonary function tests. Mean relative enhancement ratio and mean wash-in time on MRI and CT-based functional lung volume (CT-based FLV) as well as the ratio of airway wall area to total airway area on MDCT were computationally calculated. Then, all indexes were significantly correlated with functional parameters. To determine the efficacy of all indexes for clinical stage classification, the indexes for the four clinical groups were statistically compared by using Tukey's honestly significant difference multiple comparison test. Results: All indexes had significant correlations with functional parameters (p 2 -enhanced MRI for assessment of COPD in smokers is potentially as efficacious as quantitatively assessed thin-section MDCT.

An Inquiry-Oriented Approach to Span and Linear Independence: The Case of the Magic Carpet Ride Sequence

Science.gov (United States)

Wawro, Megan; Rasmussen, Chris; Zandieh, Michelle; Sweeney, George Franklin; Larson, Christine

2012-01-01

In this paper we present an innovative instructional sequence for an introductory linear algebra course that supports students' reinvention of the concepts of span, linear dependence, and linear independence. Referred to as the Magic Carpet Ride sequence, the problems begin with an imaginary scenario that allows students to build rich imagery and…

Transmutation Capability of a Once-Through Molten-Salt and Other Transmuting Reactors

International Nuclear Information System (INIS)

Greenspan, E.; Lowenthal, M.; Barnes, D.; Kawasaki, D.; Kimball, D.; Matsumoto, H.; Sagara, H.; Vietez, E.R.

2002-01-01

A preliminary assessment is done of the transmutation characteristics of three reactor technologies: a multi-batch liquid metal (LM) cooled transmuter, a once-through molten-salt (MS) transmuter and a pebble bed (PB) transmuter. It was found that for the same fractional transmutation and same k eff drop with burnup (Δk effBU ), lead-bismuth offers smaller peak-to-average core power density, and it requires a smaller pumping power but a larger and heavier core than a sodium cooled transmuter. 99 Tc cannot effectively serve as a burnable absorber to reduce Δk effBU of LM transmuters. However, addition of thorium can greatly flatten k eff and almost double the fractional transmutation of the LWR spent fuel from ∼20% to ∼40%. If the 'once-through' MS transmuter is operated with continuous complete removal of fission products, it can achieve ∼85% fractional transmutation provided that the equilibrium concentration of actinides in the MS can reach 4 mole %. If the fission products are not actively removed, the fractional transmutation is reduced to ∼75%. The fractional transmutation of a PB transmuter can exceed 40%. More thorough analysis is required to better quantify the transmutation capability of the different transmuter technologies. (authors)

Enhancing social skills through cooperative learning

Directory of Open Access Journals (Sweden)

M J Booysen

2008-04-01

Full Text Available The National Curriculum Statement of South Africa envisages qualified and competent teachers to deal with the diversity of learners and their needs in the classroom. One of the needs refers to all learners (Gr R-12 who need to acquire the necessary social skills to enable them to work effectively with others as members of a team, group, organization and community. These skills refer inter alia to: learning to work with others, listening to others, giving attention, asking clarifying questions, learning how to evaluate, and to praise others, handling conflict, reflecting on group work and allowing all group members to participate. The most obvious place to deal purposefully with the development of social skills is the classroom. This implies that alternative ways and methods of teaching must be introduced to develop the necessary social skills. This article reports on the findings obtained from a combined quantitative and qualitative study that set out to determine the levels of social competence achieved by a group of Grade 2 learners, and the possible association of a cooperative teaching and learning intervention programme for enhancing the social skills of these learners. The results revealed the latent potential of cooperative learning to enhance the social skills of Grade 2 learners. The significance of this research lies in the contribution it makes to establish the social competence of a group of Grade 2 learners and to determine the possibilities for enhancing their social skills through cooperative learning.

Onsite and Electric Backup Capabilities at Critical Infrastructure Facilities in the United States

Energy Technology Data Exchange (ETDEWEB)

Phillips, Julia A. [Argonne National Lab. (ANL), Argonne, IL (United States); Wallace, Kelly E. [Argonne National Lab. (ANL), Argonne, IL (United States); Kudo, Terence Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Eto, Joseph H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-04-01

The following analysis, conducted by Argonne National Laboratory’s (Argonne’s) Risk and Infrastructure Science Center (RISC), details an analysis of electric power backup of national critical infrastructure as captured through the Department of Homeland Security’s (DHS’s) Enhanced Critical Infrastructure Program (ECIP) Initiative. Between January 1, 2011, and September 2014, 3,174 ECIP facility surveys have been conducted. This study focused first on backup capabilities by infrastructure type and then expanded to infrastructure type by census region.

OMPS Near Real-time Products Available Through NASA LANCE (Land Atmosphere Near Real-time Capability for EOS)

Science.gov (United States)

Warnock, A.; Durbin, P. B.; Cechini, M. F.; Masuoka, E.

2017-12-01

Near real-time (NRT) images from the NASA Ozone Mapping and Profiler Suite (OMPS) for sulfur dioxide, total column ozone and aerosol index products are now available through NASA's online Land Atmosphere Near real-time Capability for EOS (LANCE) system. Color palettes, image dimensions and data ranges have been aligned with the corresponding OMI products, allowing for direct comparison of OMPS NRT images with OMI NRT images already available in NASA Worldview. The images are delivered to LANCE within hours of satellite observation. LANCE NRT imagery can be interactively viewed through Worldview and the Global Imagery Browse Services (GIBS).

Comparativa de diferentes tipos de efemérides GNSS en cálculo de grandes líneas base con Magnet Office.

OpenAIRE

Pou Peña, Guillermo

2016-01-01

El objetivo de este Trabajo de Fin de Grado es hallar la influencia de cada tipo de efeméride en la precisión a posteriori de las coordenadas de un punto de la línea base. Para ello, se plantea una comparativa entre líneas base en función de la longitud, la duración de la sesión, la constelación y el tipo de efemérides. Todo ello, eligiendo puntos de control en la Península Ibérica y contrastando las soluciones sobre el marco de referencia ETRS89. No se pretende buscar la máxima precisión ...

Enhancing pseudocapacitive kinetics of nanostructured MnO2 through anchoring onto biomass-derived porous carbon

Science.gov (United States)

Chen, Qiongyu; Chen, Jizhang; Zhou, Yuyang; Song, Chao; Tian, Qinghua; Xu, Junling; Wong, Ching-Ping

2018-05-01

The rational construction of heterostructured electrode materials that deliver superior performances to their individual counterparts offers an attractive strategy for supercapacitors. Herein, we anchor low-crystalline nanostructured MnO2 onto soybean stalk-derived carbon matrix through chemical activation and subsequent hydrothermal reaction. The highly porous and conductive matrix can effectively enhance pseudocapacitive kinetics of nanostructured MnO2. Therefore, the obtained nanocomposite exhibits high specific capacitance (384.9 F g-1 at a current density of 0.5 A g-1), great rate capability (185.0 F g-1 at 20 A g-1), and superior cyclability (90.7% capacitance retention after 5000 cycles). Using this nanocomposite as the positive electrode material, an asymmetric supercapacitor (ASC) is assembled, and achieves high specific energy of 34.2 Wh kg-1 and high specific power of 9.58 kW kg-1. The results of this study demonstrate great potential of combining biomass-derived porous carbon with metal oxides.

A comparison of leisure constraints among three outdoor recreation activities: whitewater rafting, canoeing and overnight horseback riding

Science.gov (United States)

Gyan P. Nyaupane; Duarte B. Morais; Alan Graefe

2003-01-01

The purpose of this study was to compare leisure constraints across three outdoor recreation activities, whitewater rafting, canoeing, and overnight horseback riding, in the context of the three-dimensional leisure constraints model proposed by Crawford and Godbey (1987). The sample consisted of 650 outdoor enthusiasts from 14 U.S. states who showed an interest in...

Simulations of Carnival Rides and Rube Goldberg Machines for the Visualization of Concepts of Statics and Dynamics

Science.gov (United States)

Howard, William; Williams, Richard; Yao, Jason

2010-01-01

Solid modeling is widely used as a teaching tool in summer activities with high school students. The addition of motion analysis allows concepts from statics and dynamics to be introduced to students in both qualitative and quantitative ways. Two sets of solid modeling projects--carnival rides and Rube Goldberg machines--are shown to allow the…

A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

OpenAIRE

Yoo, Cheol-Hee; Chung, Il-Yop; Yoo, Hyun-Jae; Hong, Sung-Soo

2014-01-01

Grid codes in many countries require low-voltage ride-through (LVRT) capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (P...

Siemens Wind Power 3.6 MW wind turbines for large offshore wind farms

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, Vladislav; Nygaard Nielsen, Joergen; Thisted, Jan; Groendahl, Erik; Egedal, Per; Noertoft Frydensbjerg, Michael; Jensen, Kim Hoej [Siemens Wind Power A/S, Brande (Denmark)

2008-07-01

Siemens Wind power A/S is the key player on the offshore wind power market. The Siemens Wind Power 3.6 MW variable-speed wind turbine is among the word's largest, most advanced and competitive wind turbines with a solid portfolio of large offshore wind farms. Transmission system operators and developers require dynamic wind turbine models for evaluation of fault-ride-through capability and investigations of power system stability. The even larger size of the on- and offshore wind farms has entailed that the grid impact of the voltage and frequency control capability of the wind farm can be appropriated modelled and evaluated. Siemens Wind Power has developed a dynamic model of the 3.6 MW variable-speed wind turbine with the fault-ride-through sequences and models of the voltage and frequency controllers to be applied for large offshore wind farms. The dynamic models have been implemented in the commercially available simulation tools such as DIgSILENT PowerFactory and Siemens PTI PSS/E and successfully validated from measurements. (orig.)

Enhancing Mediated Interpersonal Communication through Affective Haptics

Science.gov (United States)

Tsetserukou, Dzmitry; Neviarouskaya, Alena; Prendinger, Helmut; Kawakami, Naoki; Ishizuka, Mitsuru; Tachi, Susumu

Driven by the motivation to enhance emotionally immersive experience of real-time messaging in 3D virtual world Second Life, we are proposing a conceptually novel approach to reinforcing (intensifying) own feelings and reproducing (simulating) the emotions felt by the partner through specially designed system, iFeel_IM!. In the paper we are describing the development of novel haptic devices (HaptiHeart, HaptiHug, HaptiTickler, HaptiCooler, and HaptiWarmer) integrated into iFeel_IM! system, which architecture is presented in detail.

Identity Building in Organisations: Proactive Capability Development

DEFF Research Database (Denmark)

Rasmussen, Lauge Baungaard

2002-01-01

Identity building in organisations is often viewed as legitimacy of value systems of the organisation. Based on empirical studies the task of this article is to argue that such a legitimacy approach risks failing in the longer perspective, if the proactive capability development is neglected....... The participatory scenario method presented in this article is one of the possible methods to enhance identity building based on proactive capability development....

Graphical Visualization of Human Exploration Capabilities

Science.gov (United States)

Rodgers, Erica M.; Williams-Byrd, Julie; Arney, Dale C.; Simon, Matthew A.; Williams, Phillip A.; Barsoum, Christopher; Cowan, Tyler; Larman, Kevin T.; Hay, Jason; Burg, Alex

2016-01-01

NASA's pioneering space strategy will require advanced capabilities to expand the boundaries of human exploration on the Journey to Mars (J2M). The Evolvable Mars Campaign (EMC) architecture serves as a framework to identify critical capabilities that need to be developed and tested in order to enable a range of human exploration destinations and missions. Agency-wide System Maturation Teams (SMT) are responsible for the maturation of these critical exploration capabilities and help formulate, guide and resolve performance gaps associated with the EMC-identified capabilities. Systems Capability Organization Reporting Engine boards (SCOREboards) were developed to integrate the SMT data sets into cohesive human exploration capability stories that can be used to promote dialog and communicate NASA's exploration investments. Each SCOREboard provides a graphical visualization of SMT capability development needs that enable exploration missions, and presents a comprehensive overview of data that outlines a roadmap of system maturation needs critical for the J2M. SCOREboards are generated by a computer program that extracts data from a main repository, sorts the data based on a tiered data reduction structure, and then plots the data according to specified user inputs. The ability to sort and plot varying data categories provides the flexibility to present specific SCOREboard capability roadmaps based on customer requests. This paper presents the development of the SCOREboard computer program and shows multiple complementary, yet different datasets through a unified format designed to facilitate comparison between datasets. Example SCOREboard capability roadmaps are presented followed by a discussion of how the roadmaps are used to: 1) communicate capability developments and readiness of systems for future missions, and 2) influence the definition of NASA's human exploration investment portfolio through capability-driven processes. The paper concludes with a description

Canadian national nuclear forensics capability project

International Nuclear Information System (INIS)

Ball, J.; Dimayuga, I.; Summerell, I.; Totland, M.; Jonkmans, G.; Whitlock, J.; El-jaby, A.; Inrig, E.

2015-01-01

Following the 2010 Nuclear Security Summit, Canada expanded its existing capability for nuclear forensics by establishing a national nuclear forensics laboratory network, which would include a capability to perform forensic analysis on nuclear and other radioactive material, as well as on traditional evidence contaminated with radioactive material. At the same time, the need for a national nuclear forensics library of signatures of nuclear and radioactive materials under Canadian regulatory control was recognized. The Canadian Safety and Security Program, administered by Defence Research and Development Canada's Centre for Security Science (DRDC CSS), funds science and technology initiatives to enhance Canada's preparedness for prevention of and response to potential threats. DRDC CSS, with assistance from Canadian Nuclear Laboratories, formerly Atomic Energy of Canada Limited, is leading the Canadian National Nuclear Forensics Capability Project to develop a coordinated, comprehensive, and timely national nuclear forensics capability. (author)

Enhancing GIS Capabilities for High Resolution Earth Science Grids

Science.gov (United States)

Koziol, B. W.; Oehmke, R.; Li, P.; O'Kuinghttons, R.; Theurich, G.; DeLuca, C.

2017-12-01

Applications for high performance GIS will continue to increase as Earth system models pursue more realistic representations of Earth system processes. Finer spatial resolution model input and output, unstructured or irregular modeling grids, data assimilation, and regional coordinate systems present novel challenges for GIS frameworks operating in the Earth system modeling domain. This presentation provides an overview of two GIS-driven applications that combine high performance software with big geospatial datasets to produce value-added tools for the modeling and geoscientific community. First, a large-scale interpolation experiment using National Hydrography Dataset (NHD) catchments, a high resolution rectilinear CONUS grid, and the Earth System Modeling Framework's (ESMF) conservative interpolation capability will be described. ESMF is a parallel, high-performance software toolkit that provides capabilities (e.g. interpolation) for building and coupling Earth science applications. ESMF is developed primarily by the NOAA Environmental Software Infrastructure and Interoperability (NESII) group. The purpose of this experiment was to test and demonstrate the utility of high performance scientific software in traditional GIS domains. Special attention will be paid to the nuanced requirements for dealing with high resolution, unstructured grids in scientific data formats. Second, a chunked interpolation application using ESMF and OpenClimateGIS (OCGIS) will demonstrate how spatial subsetting can virtually remove computing resource ceilings for very high spatial resolution interpolation operations. OCGIS is a NESII-developed Python software package designed for the geospatial manipulation of high-dimensional scientific datasets. An overview of the data processing workflow, why a chunked approach is required, and how the application could be adapted to meet operational requirements will be discussed here. In addition, we'll provide a general overview of OCGIS

Design to Process Capabilities: challenges for the use of Process Capability Databases (PCDBs) in development

DEFF Research Database (Denmark)

Eifler, Tobias; Göhler, Simon Moritz; Howard, Thomas J.

2014-01-01

capabilities may lead to low yields and a cost/time overrun, conservatively underestimated capabilities affect quality through the reduced design space, or through increased play, rattle/noise, size or weight. A possibility to overcome the subjective assessment of variation in development projects is a Process...... and Maiti (2012), Breyfogle (2003)]. At the same time, information on the achievable manufacturing accuracy or the supplier’s performance is usually inaccurate and largely qualitative in early development stages. Design decisions as well as the choice of manufacturing processes, therefore, often rely...... Capability Data Base (PCDB) offering valuable insight into the actual or expected performance of production processes (Tata and Thornton, 1999). But although the potential benefits as well as initial challenges for the use of PCDBs have been addressed in earlier research, e. g. by Delaney and Phelan (2008...

Conceptual Model of IT Infrastructure Capability and Its Empirical Justification

Institute of Scientific and Technical Information of China (English)

QI Xianfeng; LAN Boxiong; GUO Zhenwei

2008-01-01

Increasing importance has been attached to the value of information technology (IT) infrastructure in today's organizations. The development of efficacious IT infrastructure capability enhances business performance and brings sustainable competitive advantage. This study analyzed the IT infrastructure capability in a holistic way and then presented a concept model of IT capability. IT infrastructure capability was categorized into sharing capability, service capability, and flexibility. This study then empirically tested the model using a set of survey data collected from 145 firms. Three factors emerge from the factor analysis as IT flexibility, IT service capability, and IT sharing capability, which agree with those in the conceptual model built in this study.

Sensor Alerting Capability

Science.gov (United States)

Henriksson, Jakob; Bermudez, Luis; Satapathy, Goutam

2013-04-01

There is a large amount of sensor data generated today by various sensors, from in-situ buoys to mobile underwater gliders. Providing sensor data to the users through standardized services, language and data model is the promise of OGC's Sensor Web Enablement (SWE) initiative. As the amount of data grows it is becoming difficult for data providers, planners and managers to ensure reliability of data and services and to monitor critical data changes. Intelligent Automation Inc. (IAI) is developing a net-centric alerting capability to address these issues. The capability is built on Sensor Observation Services (SOSs), which is used to collect and monitor sensor data. The alerts can be configured at the service level and at the sensor data level. For example it can alert for irregular data delivery events or a geo-temporal statistic of sensor data crossing a preset threshold. The capability provides multiple delivery mechanisms and protocols, including traditional techniques such as email and RSS. With this capability decision makers can monitor their assets and data streams, correct failures or be alerted about a coming phenomena.

Polymer-derived-SiCN ceramic/graphite composite as anode material with enhanced rate capability for lithium ion batteries

Science.gov (United States)

Graczyk-Zajac, M.; Fasel, C.; Riedel, R.

2011-08-01

We report on a new composite material in view of its application as a negative electrode in lithium-ion batteries. A commercial preceramic polysilazane mixed with graphite in 1:1 weight ratio was transformed into a SiCN/graphite composite material through a pyrolytic polymer-to-ceramic conversion at three different temperatures, namely 950 °C, 1100 °C and 1300 °C. By means of Raman spectroscopy we found successive ordering of carbon clusters into nano-crystalline graphitic regions with increasing pyrolysis temperature. The reversible capacity of about 350 mAh g-1 was measured with constant current charging/discharging for the composite prepared at 1300 °C. For comparison pure graphite and pure polysilazane-derived SiCN ceramic were examined as reference materials. During fast charging and discharging the composite material demonstrates enhanced capacity and stability. Charging and discharging in half an hour lead to about 200 and 10 mAh g-1, for the composite annealed at 1300 °C and pure graphite, respectively. A clear dependence between the final material capacity and pyrolysis temperature is found and discussed with respect to possible application in batteries, i.e. practical discharging potential limit. The best results in terms of capacity recovered under 1 V and high rate capability were also obtained for samples synthesized at 1300 °C.

Electromagnetic field enhancement and spectrum shaping through plasmonically integrated optical vortices.

Science.gov (United States)

Ahn, Wonmi; Boriskina, Svetlana V; Hong, Yan; Reinhard, Björn M

2012-01-11

We introduce a new design approach for surface-enhanced Raman spectroscopy (SERS) substrates that is based on molding the optical powerflow through a sequence of coupled nanoscale optical vortices "pinned" to rationally designed plasmonic nanostructures, referred to as Vortex Nanogear Transmissions (VNTs). We fabricated VNTs composed of Au nanodiscs by electron beam lithography on quartz substrates and characterized their near- and far-field responses through combination of computational electromagnetism, and elastic and inelastic scattering spectroscopy. Pronounced dips in the far-field scattering spectra of VNTs provide experimental evidence for an efficient light trapping and circulation within the nanostructures. Furthermore, we demonstrate that VNT integration into periodic arrays of Au nanoparticles facilitates the generation of high E-field enhancements in the VNTs at multiple defined wavelengths. We show that spectrum shaping in nested VNT structures is achieved through an electromagnetic feed-mechanism driven by the coherent multiple scattering in the plasmonic arrays and that this process can be rationally controlled by tuning the array period. The ability to generate high E-field enhancements at predefined locations and frequencies makes nested VNTs interesting substrates for challenging SERS applications. © 2011 American Chemical Society

Therapeutic Effects of Horseback Riding Therapy on Gross Motor Function in Children with Cerebral Palsy: A Systematic Review

Science.gov (United States)

Whalen, Cara N.; Case-Smith, Jane

2012-01-01

Purpose: This systematic review examined the efficacy of hippotherapy or therapeutic horseback riding (THR) on motor outcomes in children with cerebral palsy (CP). Methods: Databases were searched for clinical trials of hippotherapy or THR for children with CP. Results: Nine articles were included in this review. Although the current level of…

Coordination of Advertising Free Riding in Hybrid Channel Supply Chain

Directory of Open Access Journals (Sweden)

Jin Sha

2016-01-01

Full Text Available Advertising is a crucial tool for demand creation and market expansion; enterprises in supply chain use it widely to increase sales and improve profits. But the homogeneity of products sold in hybrid channel supply chain magnifies the positive externalities of advertising and leads to serious free-riding problem. To coordinate the supply chain effectively, firstly, this paper classifies hybrid channel supply chain based on the relationship between members and selects horizontally integrated, vertically integrated, and decentralized hybrid channel supply chains as research objects. Then, a demand function considering the common effect of price and advertising is proposed and coordination schemes for different types of supply chains are designed. Finally, a sensitivity analysis is performed to assess the impact of parameters on coordination using orthogonal experiment.

Human-Centered Design Capability

Science.gov (United States)

Fitts, David J.; Howard, Robert

2009-01-01

For NASA, human-centered design (HCD) seeks opportunities to mitigate the challenges of living and working in space in order to enhance human productivity and well-being. Direct design participation during the development stage is difficult, however, during project formulation, a HCD approach can lead to better more cost-effective products. HCD can also help a program enter the development stage with a clear vision for product acquisition. HCD tools for clarifying design intent are listed. To infuse HCD into the spaceflight lifecycle the Space and Life Sciences Directorate developed the Habitability Design Center. The Center has collaborated successfully with program and project design teams and with JSC's Engineering Directorate. This presentation discusses HCD capabilities and depicts the Center's design examples and capabilities.

Nanoantenna enhanced terahertz spectroscopy of a monolayer of cadmium selenide quantum dots

KAUST Repository

Razzari, Luca; Toma, Andrea; Tuccio, Salvatore; Prato, Mirko; De Donato, Francesco; Perucchi, Andrea; Di Pietro, Paola; Marras, Sergio; Liberale, Carlo; Proietti Zaccaria, Remo; De Angelis, Francesco De; Manna, Liberato; Lupi, Stefano; Di Fabrizio, Enzo M.

2014-01-01

Exploiting the localization and enhancement capabilities of terahertz resonant dipole nanoantennas coupled through nanogaps, we present an effective method to perform terahertz spectroscopy on an extremely small number of nano-objects.

Enhancing mathematics teachers' quality through Lesson Study.

Science.gov (United States)

Lomibao, Laila S

2016-01-01

The efficiency and effectivity of the learning experience is dependent on the teacher quality, thus, enhancing teacher's quality is vital in improving the students learning outcome. Since, the usual top-down one-shot cascading model practice for teachers' professional development in Philippines has been observed to have much information dilution, and the Southeast Asian Ministers of Education Organization demanded the need to develop mathematics teachers' quality standards through the Southeast Asia Regional Standards for Mathematics Teachers (SEARS-MT), thus, an intensive, ongoing professional development model should be provided to teachers. This study was undertaken to determine the impact of Lesson Study on Bulua National High School mathematics teachers' quality level in terms of SEARS-MT dimensions. A mixed method of quantitative-qualitative research design was employed. Results of the analysis revealed that Lesson Study effectively enhanced mathematics teachers' quality and promoted teachers professional development. Teachers positively perceived Lesson Study to be beneficial for them to become a better mathematics teacher.

Carbon monoxide poisoning in children riding in the back of pickup trucks.

Science.gov (United States)

Hampson, N B; Norkool, D M

OBJECTIVE - To describe the case characteristics of a series of children poisoned with carbon monoxide while traveling in the back of pickup trucks. DESIGN - Pediatric cases referred for treatment of carbon monoxide poisoning with hyperbaric oxygen between 1986 and 1991 were reviewed. Those cases that occurred during travel in the back of pickup trucks were selected. Clinical follow-up by telephone interview ranged from 2 to 55 months. SETTING - A private, urban, tertiary care center in Seattle, Wash. PATIENTS - Twenty children ranging from 4 to 16 years of age. INTERVENTION - All patients were treated with hyperbaric oxygen. MAIN OUTCOME MEASURES - Characteristics of the poisoning incident and clinical patient outcome. RESULTS - Of 68 pediatric patients treated for accidental carbon monoxide poisoning, 20 cases occurred as children rode in the back of pickup trucks. In 17 of these, the children were riding under a rigid closed canopy on the rear of the truck, while three episodes occurred as children rode beneath a tarpaulin. Average carboxyhemoglobin level on emergency department presentation was 18.2% +/- 2.4% (mean +/- SEM; range, 1.6% to 37.0%). Loss of consciousness occurred in 15 of the 20 children. One child died of cerebral edema, one had permanent neurologic deficits, and 18 had no recognizable sequelae related to the episode. In all cases, the truck exhaust system had a previously known leak or a tail pipe that exited at the rear rather than at the side of the pickup truck. CONCLUSIONS - Carbon monoxide poisoning is a significant hazard for children who ride in the back of pickup trucks. If possible, this practice should be avoided.

Alterations in muscular enzymes of horses competing long-distance endurance rides under tropical climate Alterações em enzimas musculares de cavalos em competições de enduro de longa distância em clima tropical

Directory of Open Access Journals (Sweden)

A.R. Teixeira-Neto

2008-06-01

Full Text Available This study tried to monitor the alterations of muscle enzymes activity - creatinokinase (CK, lactate dehydrogenase (LDH, and aspartate aminotransferase (AST - in a group of horses that participated of 70 and 100km distance rides in five competitions of an annual endurance championship under tropical climate. Pre ride levels (U/l were 245.13±9.84 for CK, 496.61±14.76 for LDH, and 328.95±8.65 for AST. When compared to these levels, the results revealed a significant decrease in all enzymes activities in the first moment of the rides. Peak levels, significantly different, were reached, immediately after rides by CK (413.591±50.75; 24 hours post rides by LDH (628.61±33.30; and 48 hours after rides by AST (389.89±16.96. Monitoring of recovery period revealed different behavior among enzymes activities with CK values returning to pre ride values (279.61±23.05 24 hours post rides, while LDH and AST values returned to pre ride values (505.25±33.78 and 359.35±24.90, respectively 72 hours post rides. These data revealed different alterations in concentration of muscular enzymes in endurance horses directly related to the duration of the effort.Estudaram-se as alterações de atividade das enzimas musculares creatino quinase (CK, lactato desidrogenase (LDH e aspartato aminotransferase (AST em um grupo de cavalos que utilizados em provas de enduro de 70 e 100km de distância, em cinco competições. Os valores (U/l basais (antes da largada foram 245,13±9,84 para CK, 496,61±14,76 para LDH e 328,95±8,65 para AST. Todas as atividades das enzimas decresceram no primeiro momento das provas (~30km. Valores de pico, significativamente diferentes, foram alcançados para CK (413,59±50,75 imediatamente após 70km de distância; 24 horas após para LDH (628,61±33,30; e 48 horas após as provas para AST (389,89±16,96. A monitoração do período de recuperação revelou diferente comportamento entre as concentrações enzimáticas com CK retornando aos

SIGMA Release v1.2 - Capabilities, Enhancements and Fixes

Energy Technology Data Exchange (ETDEWEB)

Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States); Grindeanu, Iulian R. [Argonne National Lab. (ANL), Argonne, IL (United States); Ray, Navamita [Argonne National Lab. (ANL), Argonne, IL (United States); Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Wu, Danqing [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-30

In this report, we present details on SIGMA toolkit along with its component structure, capabilities, and feature additions in FY15, release cycles, and continuous integration process. These software processes along with updated documentation are imperative to successfully integrate and utilize in several applications including the SHARP coupled analysis toolkit for reactor core systems funded under the NEAMS DOE-NE program.

SIGMA Release v1.2 - Capabilities, Enhancements and Fixes

International Nuclear Information System (INIS)

Mahadevan, Vijay; Grindeanu, Iulian R.; Ray, Navamita; Jain, Rajeev; Wu, Danqing

2015-01-01

In this report, we present details on SIGMA toolkit along with its component structure, capabilities, and feature additions in FY15, release cycles, and continuous integration process. These software processes along with updated documentation are imperative to successfully integrate and utilize in several applications including the SHARP coupled analysis toolkit for reactor core systems funded under the NEAMS DOE-NE program.

Strong Photoluminescence Enhancement of Silicon Oxycarbide through Defect Engineering

Directory of Open Access Journals (Sweden)

Brian Ford

2017-04-01

Full Text Available The following study focuses on the photoluminescence (PL enhancement of chemically synthesized silicon oxycarbide (SiCxOy thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD, and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H2, 95% N2 ambients, modifying the observed white light emission. The observed white luminescence was found to be inversely related to the carbonyl (C=O bond density present in the films. The peak-to-peak PL was enhanced ~18 and ~17 times for, respectively, the two SiCxOy matrices, oxygen-rich and carbon-rich SiCxOy, via post-deposition passivations. Through a combinational and systematic Fourier transform infrared spectroscopy (FTIR and PL study, it was revealed that proper tailoring of the passivations reduces the carbonyl bond density by a factor of ~2.2, corresponding to a PL enhancement of ~50 times. Furthermore, the temperature-dependent and temperature-dependent time resolved PL (TDPL and TD-TRPL behaviors of the nitrogen and forming gas passivated SiCxOy thin films were investigated to acquire further insight into the ramifications of the passivation on the carbonyl/dangling bond density and PL yield.

Canadian national nuclear forensics capability project

Energy Technology Data Exchange (ETDEWEB)

Ball, J.; Dimayuga, I., E-mail: joanne.ball@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Summerell, I. [Royal Canadian Mounted Police, Ottawa, Ontario (Canada); Totland, M. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Jonkmans, G. [Defence Research and Development Canada, Ottawa, Ontario (Canada); Whitlock, J. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); El-jaby, A. [Canadian Nuclear Safety Commission, Ottawa, Ontario (Canada); Inrig, E. [Defence Research and Development Canada, Ottawa, Ontario (Canada)

2015-06-15

Following the 2010 Nuclear Security Summit, Canada expanded its existing capability for nuclear forensics by establishing a national nuclear forensics laboratory network, which would include a capability to perform forensic analysis on nuclear and other radioactive material, as well as on traditional evidence contaminated with radioactive material. At the same time, the need for a national nuclear forensics library of signatures of nuclear and radioactive materials under Canadian regulatory control was recognized. The Canadian Safety and Security Program, administered by Defence Research and Development Canada's Centre for Security Science (DRDC CSS), funds science and technology initiatives to enhance Canada's preparedness for prevention of and response to potential threats. DRDC CSS, with assistance from Canadian Nuclear Laboratories, formerly Atomic Energy of Canada Limited, is leading the Canadian National Nuclear Forensics Capability Project to develop a coordinated, comprehensive, and timely national nuclear forensics capability. (author)

Compilation of Sandia Laboratories technical capabilities

International Nuclear Information System (INIS)

Lundergan, C.D.; Mead, P.L.

1975-11-01

This report is a compilation of 17 individual documents that together summarize the technical capabilities of Sandia Laboratories. Each document in this compilation contains details about a specific area of capability. Examples of application of the capability to research and development problems are provided. An eighteenth document summarizes the content of the other seventeen. Each of these documents was issued with a separate report number (SAND 74-0073A through SAND 74-0091, except -0078)

Personality Assessment: A Competency-Capability Perspective.

Science.gov (United States)

Kaslow, Nadine J; Finklea, J Tyler; Chan, Ginny

2018-01-01

This article begins by reviewing the proficiency of personality assessment in the context of the competencies movement, which has dominated health service psychology in recent years. It examines the value of including a capability framework for advancing this proficiency and enhancing the quality of personality assessments, including Therapeutic Assessment (Finn & Tonsager, 1997 ), that include a personality assessment component. This hybrid competency-capability framework is used to set the stage for the conduct of personality assessments in a variety of contexts and for the optimal training of personality assessment. Future directions are offered in terms of ways psychologists can strengthen their social contract with the public and offer a broader array of personality assessments in more diverse contexts and by individuals who are both competent and capable.

Towards a dynamic concept of alliance capability

OpenAIRE

SLUYTS, Kim; MARTENS, Rudy; MATTHYSSENS, Paul

2008-01-01

This paper has a threefold purpose. First, we offer a literature review on alliance capability based on strategic and competence based management literature. Second, we extend existing literature on alliance capability by breaking this concept down into five sub capabilities, which are each linked to a stage of the alliance life cycle. Finally, we suggest how firms can support these capabilities through structural, technological and people-related tools and techniques. We argue that current l...

Community psychology and the capabilities approach.

Science.gov (United States)

Shinn, Marybeth

2015-06-01

What makes for a good life? The capabilities approach to this question has much to offer community psychology, particularly with respect to marginalized groups. Capabilities are freedoms to engage in valued social activities and roles-what people can do and be given both their capacities, and environmental opportunities and constraints. Economist Amartya Sen's focus on freedoms and agency resonates with psychological calls for empowerment, and philosopher Martha Nussbaum's specification of requirements for a life that is fully human provides an important guide for social programs. Community psychology's focus on mediating structures has much to offer the capabilities approach. Parallels between capabilities, as enumerated by Nussbaum, and settings that foster positive youth development, as described in a National Research Council Report (Eccles and Gootman (Eds) in Community programs to promote youth development. National Academy Press, Washington, 2002) suggest extensions of the approach to children. Community psychologists can contribute to theory about ways to create and modify settings to enhance capabilities as well as empowerment and positive youth development. Finally, capabilities are difficult to measure, because they involve freedoms to choose but only choices actually made or enacted can be observed. The variation in activities or goals across members of a setting provides a measure of the capabilities that the setting fosters.

Enhancing the cellular uptake of Py–Im polyamides through next-generation aryl turns

OpenAIRE

Meier, Jordan L.; Montgomery, David C.; Dervan, Peter B.

2012-01-01

Pyrrole–imidazole (Py–Im) hairpin polyamides are a class of programmable, sequence-specific DNA binding oligomers capable of disrupting protein–DNA interactions and modulating gene expression in living cells. Methods to control the cellular uptake and nuclear localization of these compounds are essential to their application as molecular probes or therapeutic agents. Here, we explore modifications of the hairpin γ-aminobutyric acid turn unit as a means to enhance cellular uptake and biologica...

A novel HTS SMES application in combination with a permanent magnet synchronous generator type wind power generation system

Energy Technology Data Exchange (ETDEWEB)

Kim, G.H.; Kim, A.R.; Kim, S. [Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea, Republic of); Park, M., E-mail: paku@changwon.ac.kr [Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, I.K. [Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea, Republic of); Seong, K.C. [Superconducting Device and Cryogenics Group, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Won, Y.J. [Korea Electric Power Corporation, Changwon 641-241 (Korea, Republic of)

2011-11-15

A novel connection topology of SMES is proposed in this paper. Structure of the proposed system is cost-effective because it reduces a converter. The proposed system smoothens output power of wind power generation system. Advantage of the system is to improve the low voltage ride through capability. Superconducting magnetic energy storage (SMES) system is a DC current driven device and can be utilized to improve power quality particularly in connection with renewable energy sources due to higher efficiency and faster response than other devices. This paper suggests a novel connection topology of SMES which can smoothen the output power flow of the wind power generation system (WPGS). The structure of the proposed system is cost-effective because it reduces a power converter in comparison with a conventional application of SMES. One more advantage of SMES in the proposed system is to improve the capability of low voltage ride through (LVRT) for the permanent magnet synchronous generator (PMSG) type WPGS. The proposed system including a SMES has been modeled and analyzed by a PSCAD/EMTDC. The simulation results show the effectiveness of the novel SMES application strategy to not only mitigate the output power of the PMSG but also improve the capability of LVRT for PMSG type WPGS.

A novel HTS SMES application in combination with a permanent magnet synchronous generator type wind power generation system

International Nuclear Information System (INIS)

Kim, G.H.; Kim, A.R.; Kim, S.; Park, M.; Yu, I.K.; Seong, K.C.; Won, Y.J.

2011-01-01

A novel connection topology of SMES is proposed in this paper. Structure of the proposed system is cost-effective because it reduces a converter. The proposed system smoothens output power of wind power generation system. Advantage of the system is to improve the low voltage ride through capability. Superconducting magnetic energy storage (SMES) system is a DC current driven device and can be utilized to improve power quality particularly in connection with renewable energy sources due to higher efficiency and faster response than other devices. This paper suggests a novel connection topology of SMES which can smoothen the output power flow of the wind power generation system (WPGS). The structure of the proposed system is cost-effective because it reduces a power converter in comparison with a conventional application of SMES. One more advantage of SMES in the proposed system is to improve the capability of low voltage ride through (LVRT) for the permanent magnet synchronous generator (PMSG) type WPGS. The proposed system including a SMES has been modeled and analyzed by a PSCAD/EMTDC. The simulation results show the effectiveness of the novel SMES application strategy to not only mitigate the output power of the PMSG but also improve the capability of LVRT for PMSG type WPGS.

Frequency support capability of variable speed wind turbine based on electromagnetic coupler

DEFF Research Database (Denmark)

You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

2015-01-01

In the variable speed wind turbine based on electromagnetic coupler (WT-EMC), a synchronous generator is directly coupled with grid. So like conventional power plants WT-EMC is able to support grid frequency inherently. But due to the reduced inertia of synchronous generator, its frequency support...... capability has to be enhanced. In this paper, the frequency support capability of WT-EMC is studied at three typical wind conditions and with two control strategies-droop control and inertial control to enhance its frequency support capability. The synchronous generator speed, more stable than the grid...

Relation between riding quality of MAGLEV vehicle and guideway construction accuracy. Chodendo jiki fujoshiki tetsudo guideway no seko seido to norigokochi level

Energy Technology Data Exchange (ETDEWEB)

Matsuura, A; Hashimoto, S; Furukawa, A [Railway Technology Research Institute, Tokyo (Japan)

1994-01-15

Good riding quality of MAGLEV vehicle requires construction of its guideway to a high level of accuracy. This paper discusses the relation of the power spectrum density (hereinafter the PSD) made up of guideway construction accuracy and its deviation with the level of riding comfort. The discussion uses the 'riding comfort affecting coefficient' consisting of the unit construction length, vehicle's travelling speed, and vibration characteristics. The PSD, which has been used to evaluate track deviation in the iron wheel/rail system railways, is derived from the number of limit exceeded point, the value 'P' as a track deviation coefficient, and the PSD. The relation between the standard deviation in construction errors and the PSD was derived based on track construction methods. This calculation method is characterized by a function with a step form. The relation between the deviation and the level was quantified using this PSD. Its practicability was verified by a simulated re-inspection of the guideway deviation. Correlation between the level and the construction accuracy was elucidated, and a method for determining the criteria for construction accuracy was established. A side wall beam installing vehicle has been fabricated on a trial basis for a side wall system for the guideway, and installation accuracy tests are being carried out. 14 refs., 12 figs., 3 tabs.

Influence of girth strap placement and panel flocking material on the saddle pressure pattern during riding of horses.

Science.gov (United States)

Byström, A; Stalfelt, A; Egenvall, A; Von Peinen, K; Morgan, K; Roepstorff, L

2010-11-01

Saddle fit is well recognised as an important factor for the health and performance of riding horses. However, only few studies have addressed general effects of different saddle construction details within a group of horses. To assess the influence of girth strap placement, traditional vs. v-system, and panel flocking material, wool vs. synthetic foam, on the saddle pressure pattern during riding. Six horses were ridden by 3 riders in sitting and rising trot and sitting canter. Saddle pressure was measured with 3 different saddle variants: 1) wool flocked panels and traditional girthing (baseline); 2) wool flocked panels and v-system girthing; and 3) foam filled panels and traditional girthing. From the pressure data, a number of descriptive variables were extracted. These were analysed using ANCOVA models with horse, rider, saddle, seat (sitting/rising, trot only) and speed as independent variables. With foam filled panels stride maximum pressures under the hind part of the saddle increased by 7-12% and the area under the saddle with a stride mean pressure >11 kPa increased by 114 cm(2) in trot and 127 cm(2) in canter. With v-system girthing, the latter variable also increased, but only by 53 and 38 cm(2) in trot and canter, respectively. In addition, stride maximum pressures under the front part of the saddle tended to increase (≤ 9%). Both flocking material and girthing have a significant influence on the saddle pressure and should thus be considered in saddle fitting. Wool seems a better flocking material than foam of the type used in the current study. For girthing, traditional placement seems equally good if not better than the v-system. However, further studies are needed to show if these results are valid for a larger population of riding horses. © 2010 EVJ Ltd.

(Ne)efektivní fungování skupin: Free-riding na Karlově Univerzitě

OpenAIRE

Kibitzki, Jonas Moritz

2016-01-01

Group work is pervading modern society's life with potentially huge advantages but also the peril of motivational losses. This master thesis focuses on the latter ones, namely on free-riding and social loafing, in the educational context. I conducted a field research at the Institute of Economic Studies at Charles University in Prague. The results are set into context with existing studies from the US, scrutinizing the generalizability of these studies. Students of this sample consider teamwo...

Upgrading of TREAT experimental capabilities

International Nuclear Information System (INIS)

Dickerman, C.E.; Rose, D.; Bhattacharyya, S.K.

1982-01-01

The TREAT facility at the Argonne National Laboratory site in the Idaho National Engineering Laboratory is being upgraded to provide capabilities for fast-reactor-safety transient experiments not possible at any other experimental facility. Principal TREAT Upgrade (TU) goal is provision for 37-pin size experiments on energetics of core-disruptive accidents (CDA) in fast breeder reactor cores with moderate sodium void coefficients. this goal requires a significant enhancement of the capabilities of the TREAT facility, specifically including reactor control, hardened neutron spectrum incident on the test sample, and enlarged building. The upgraded facility will retain the capability for small-size experiments of the types currently being performed in TREAT. Reactor building and crane upgrading have been completed. TU schedules call for the components of the upgraded reactor system to be finished in 1984, including upgraded TREAT fuel and control system, and expanded coverage by the hodoscope fuel-motion diagnostics system

Beam-Riding Analysis of a Parabolic Laser-thermal Thruster

International Nuclear Information System (INIS)

Scharring, Stefan; Eckel, Hans-Albert; Roeser, Hans-Peter

2011-01-01

Flight experiments with laser-propelled vehicles (lightcrafts) are often performed by wire-guidance or with spin-stabilization. Nevertheless, the specific geometry of the lightcraft's optics and nozzle may provide for inherent beam-riding properties. These features are experimentally investigated in a hovering experiment at a small free flight test range with an electron-beam sustained pulsed CO 2 high energy laser. Laser bursts are adapted with a real-time control to lightcraft mass and impulse coupling for ascent and hovering in a quasi equilibrium of forces. The flight dynamics is analyzed with respect to the impulse coupling field vs. attitude, given by the lightcraft's offset and its inclination angle against the beam propagation axis, which are derived from the 3D-reconstruction of the flight trajectory from highspeed recordings. The limitations of the experimental parameters' reproducibility and its impact on flight stability are explored in terms of Julia sets. Solution statements for dynamic stabilization loops are presented and discussed.

Validation of the Chinese-language brief sensation seeking scale: implications for risky riding behaviors of parental motorcyclists and their child passengers.

Science.gov (United States)

Fan, Hsiu-Ping; Lin, Mau-Roung; Bai, Chyi-Huey; Huang, Ping-Wen; Chiang, Yung-Hsiao; Chiu, Wen-Ta

2014-12-01

Motorcycles are the leading cause of road traffic deaths in the Western Pacific and Southeast Asia, where Mandarin Chinese is the most commonly used language. Sensation seeking (SS) is reported to correlate with many risky motor vehicle behaviors, and therefore a culture-adapted Chinese instrument is needed to assess this personality trait in Chinese-speaking motorcycling populations. The standard front and blinded-backward process was carried out to formulate the Chinese-language Brief Sensation Seeking Scale (C-BSSS). 193 parental motorcyclists who rode with their young children were interviewed concerning their SS levels, demographics, riding behaviors, and the driving/riding experiences. A random sample of 30 subjects was re-interviewed 1-2 weeks later to examine the test-retest reliability. Psychometric analyses revealed satisfactory item characteristics, internal consistency, intraobserver reliability, and interobserver reliability. Additionally, parental motorcyclists who had the following characteristics were more likely to be the high sensation seekers (SSers), including male, younger age, presenting risky motor vehicle behaviors of themselves (e.g., higher riding speeds, operating after drinking, using a mobile phone while operating, and receiving a traffic ticket), and carrying child passengers who demonstrated dangerous motorcycling behaviors (e.g., a younger age, non-helmeted, and overloaded). We conclude that the C-BSSS is a useful and reliable measure of SS for ethnic Chinese populations. This instrument may be helpful to develop the future prevention strategy of motorcycle injuries in Chinese parental motorcyclists and their young child passengers. Copyright © 2014. Published by Elsevier Ltd.

Enhancing Students' Communication Skills through Problem Posing and Presentation

Science.gov (United States)

Sugito; E. S., Sri Mulyani; Hartono; Supartono

2017-01-01

This study was to explore how enhance communication skill through problem posing and presentation method. The subjects of this research were the seven grade students Junior High School, including 20 male and 14 female. This research was conducted in two cycles and each cycle consisted of four steps, they were: planning, action, observation, and…

Compilation of Sandia Laboratories technical capabilities

Energy Technology Data Exchange (ETDEWEB)

Lundergan, C. D.; Mead, P. L. [eds.

1975-11-01

This report is a compilation of 17 individual documents that together summarize the technical capabilities of Sandia Laboratories. Each document in this compilation contains details about a specific area of capability. Examples of application of the capability to research and development problems are provided. An eighteenth document summarizes the content of the other seventeen. Each of these documents was issued with a separate report number (SAND 74-0073A through SAND 74-0091, except -0078). (RWR)

ANTECEDENTS OF CUSTOMER RELATIONSHIP MANAGEMENT CAPABILITIES

Directory of Open Access Journals (Sweden)

Tuleu Daniela

2015-07-01

Full Text Available Customer relationship management, as a process to manage customer relationship initiation, maintenance and termination to maximize the value of the relationship portfolio, is an evolving process. In recent years, the development of interactive technologies (social media have revolutionized the interaction between firms and their customers and between customers. The impact of technology on CRM is improving ways of collecting and processing customer information and transforming communication with customers. In the context of the development of social networks, the introduction of social media applications in customer relationship management activities bring important changes in this area. Thus, managers need to pay attention to the interaction management as an important process of CRM and enhance the customer relationship management capabilities. The study propose a conceptual research model of several antecedents of customer relationship managements capabilities and provide the linkage between this antecedents and CRM capabilities. First, following review of existing research literature related to customer relationship management, there are some conceptual clarification on customer relationship management. Second, are presented the working concepts: the adoption of interactive technologies, customer concept, customer empowerment, customer relationship orientation and customer-centric management system. Then, it is proposed the conceptual model and finally are presented conclusions, managerial implications, limitations and research directions. From a theoretical perspective, this paper highlights the importance of marketing actions at the individual customer level and reveal the impact of adoption by companies of interactive technologies so that organizations have the opportunity to engage in conversations with customers and respond in real time the requirements that they launched the online environment. Nowadays, customers feel empowered and play

Cost-effective way to enhance the capabilities of the LCLS baseline

International Nuclear Information System (INIS)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2010-08-01

This paper discusses the potential for enhancing the LCLS hard X-ray FEL capabilities. In the hard X-ray regime, a high longitudinal coherence will be the key to such performance upgrade. The method considered here to obtain high longitudinal coherence is based on a novel single-bunch self-seeding scheme exploiting a single crystal monochromator, which is extremely compact and can be straightforwardly installed in the LCLS baseline undulator. We present simulation results dealing with the LCLS hard X-ray FEL, and show that this method can produce fully-coherent X-ray pulses at 100 GW power level. With the radiation beam monochromatized down to the Fourier transform limit, a variety of very different techniques leading to further improvements of the LCLS performance become feasible. In particular, we describe an efficient way for obtaining full polarization control at the LCLS hard X-ray FEL. We also propose to exploit crystals in the Bragg reflection geometry as movable deflectors for the LCLS X-ray transport systems. The hard X-ray beam can be deflected of an angle of order of a radian without perturbations. The monochromatization of the output radiation constitutes the key for reaching such result. Finally, we describe a newoptical pump - hard X-ray probe technique which will allow time-resolved studies at the LCLS baseline on the femtosecond time scale. The principle of operation of the proposed scheme is essentially based on the use of the time jitter between pump and probe pulses. This eliminates the need for timing XFELs to high-power conventional lasers with femtosecond accuracy. (orig.)

Cost-effective way to enhance the capabilities of the LCLS baseline

Energy Technology Data Exchange (ETDEWEB)

Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2010-08-15