WorldWideScience

Sample records for ride quality guideway

  1. 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.

  2. 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.

  3. Design and validation of a slender guideway for Maglev vehicle by simulation and experiment

    Science.gov (United States)

    Han, Jong-Boo; Han, Hyung-Suk; Kim, Sung-Soo; Yang, Seok-Jo; Kim, Ki-Jung

    2016-03-01

    Normally, Maglev (magnetic levitation) vehicles run on elevated guideways. The elevated guideway must satisfy various load conditions of the vehicle, and has to be designed to ensure ride quality, while ensuring that the levitation stability of the vehicle is not affected by the deflection of the guideway. However, because the elevated guideways of Maglev vehicles in South Korea and other countries fabricated so far have been based on over-conservative design criteria, the size of the structures has increased. Further, from the cost perspective, they are unfavourable when compared with other light rail transits such as monorail, rubber wheel, and steel wheel automatic guided transit. Therefore, a slender guideway that does have an adverse effect on the levitation stability of the vehicle is required through optimisation of design criteria. In this study, to predict the effect of various design parameters of the guideway on the dynamic behaviour of the vehicle, simulations were carried out using a dynamics model similar to the actual vehicle and guideway, and a limiting value of deflection ratio of the slender guideway to ensure levitation control is proposed. A guideway that meets the requirement as per the proposed limit for deflection ratio was designed and fabricated, and through a driving test of the vehicle, the validity of the slender guideway was verified. From the results, it was confirmed that although some increase in airgap and cabin acceleration was observed with the proposed slender guideway when compared with the conventional guideway, there was no notable adverse effect on the levitation stability and ride quality of the vehicle. Therefore, it can be inferred that the results of this study will become the basis for establishing design criteria for slender guideways of Maglev vehicles in future.

  4. 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.

  5. 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...

  6. The concept of the mechanically active guideway as a novel approach to maglev

    Science.gov (United States)

    Horwath, T. G.

    1992-01-01

    A maglev system that is suitable for operation in the United States will have to meet unique requirements which determine the major systems characteristics. Maglev configurations presently developed in Germany and Japan are based on conventional maglev concepts and as such do not meet all of the requirements. A novel maglev guideway concept is introduced as a solution. This concept, the mechanically active guideway, is articulated in three degrees of freedom and assumes system functions which normally reside in the maglev vehicle. The mechanically active guideway contains spatially distributed actuators which are energized under computer control at the time of vehicle passage to achieve bank angle adjustment and ride quality control. A typical realization of the concept is outlined.

  7. 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.

  8. Influence of guideway flexibility on maglev vehicle/guideway dynamic forces. Final report, July 1991-July 1992

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, L E; Ahlbeck, D R; Stekly, Z J; Gregorek, G M

    1992-07-01

    The report presents the results of a study investigating the dynamic interaction between aerial structures and maglev vehicles. The study includes three dimensional responses for attractive (EMS) maglev vehicle and repulsive (EDS) maglev vehicles and six different guideway structures. The analysis is conducted using original time domain computer models which incorporate up to 52 degrees of freedom for EMS systems and 44 degrees of freedom for the EDS systems, including multiple span guideways, multiple-vehicle trains, aerodynamic inputs with the special relations and structural properties associated with each major system component, and with appropriate maglev suspension characteristics interconnecting vehicle to guideway. The various guideway structure and vehicle combinations are analyzed separately for two representative guideway lengths of 21m and 39m. Results are presented for vehicle accelerations in terms of ride comfort accelerations and for guideway accelerations and bending moments. Comparisons from the analysis include EMS vs. EDS system responses, effects of span length, effects of position in car, effects of multiple-vehicle trains, effects of multiple simple span guideways vs. continuous span guideways, effects of wind gusts, and effects of beam bearing pad stiffness. Costs of each guideway is estimated in 1992 dollars.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Z-Source Inverter Based Power Quality Compensator with Enhanced Ride-Through Capability

    DEFF Research Database (Denmark)

    Gajanayake, C.J.; Vilathgamuwa, D.M.; Loh, P.C.

    2007-01-01

    Distributed generation has been gaining acceptance over the years and it has the potential to provide reliable power to sensitive loads. However, distributed networks are prone to unbalanced faults conditions. This makes single inverter DG systems unsuitable as UPS systems. This paper proposes...... a Zsource inverter based power quality compensator and a control structure that supplies high quality voltage to the connected sensitive load in the presence of other non linear loads. The proposed topology consists of combination of shunt and series inverters connected to a common Z-source impedance...... network. The shunt inverter is controlled to maintain a quality voltage waveform at the load bus. Whereas the series inverter enhances the ride-through capability during grid faults, protects the shunt inverter by limiting the current and also controls the power delivered to the grid. The performance...

  14. 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.

  15. Straightness measurement of large machine guideways

    Directory of Open Access Journals (Sweden)

    W. Ptaszyñski

    2011-10-01

    Full Text Available This paper shows the guideway types of large machines and describes problems with their straightness measurement. A short description of straightness measurement methods and the results of investigation in straightness of 10 meter long guideways of a CNC machine by means of the XL-10 Renishaw interferometer are also presented.

  16. Open tube guideway for high speed air cushioned vehicles

    Science.gov (United States)

    Goering, R. S. (Inventor)

    1974-01-01

    This invention is a tubular shaped guideway for high-speed air-cushioned supported vehicles. The tubular guideway is split and separated such that the sides of the guideway are open. The upper portion of the tubular guideway is supported above the lower portion by truss-like structural members. The lower portion of the tubular guideway may be supported by the terrain over which the vehicle travels, on pedestals or some similar structure.

  17. Vehicle/Guideway Interaction in Maglev Systems

    Science.gov (United States)

    1992-03-01

    Technology Division Materials and Components in Maglev Systems Technology Division Materials and Components Technology Division byY. Cai, S. S. Chen, and D. M...Transportation Systems Reports (UC-330, Vehicle/Guideway Interaction in Maglev Systems by Y. Cai and S. S. Chen Materials and Components Technology Division D. M...Surface Irregularities ...................................... 32 4 Vehicle/Guideway Interaction in Transrapid Maglev System .................. 34 4.1

  18. 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.

  19. Aerodynamic vibrations of a maglev vehicle running on flexible guideways under oncoming wind actions

    Science.gov (United States)

    Yau, J. D.

    2010-05-01

    This paper intends to present a computational framework of aerodynamic analysis for a maglev (magnetically levitated) vehicle traveling over flexible guideways under oncoming wind loads. The guideway unit is simulated as a series of simple beams with identical span and the maglev vehicle as a rigid car body supported by levitation forces. To carry out the interaction dynamics of maglev vehicle/guideway system, this study adopts an onboard PID (proportional-integral-derivative) controller based on Ziegler-Nicholas (Z-N) method to control the levitation forces. Interaction of wind with high-speed train is a complicated situation arising from unsteady airflow around the train. In this study, the oncoming wind loads acting on the running maglev vehicle are generated in temporal/spatial domain using digital simulation techniques that can account for the moving effect of vehicle's speed and the spatial correlation of stochastic airflow velocity field. Considering the motion-dependent nature of levitation forces and the non-conservative characteristics of turbulent airflows, an iterative approach is used to compute the interaction response of the maglev vehicle/guideway coupling system under wind actions. For the purpose of numerical simulation, this paper employs Galerkin's method to convert the governing equations containing a maglev vehicle into a set of differential equations in generalized systems, and then solve the two sets of differential equations using an iterative approach with the Newmark method. From the present investigation, the aerodynamic forces may result in a significant amplification on acceleration amplitude of the running maglev vehicle at higher speeds. For this problem, a PID+LQR (linear quadratic regulator) controller is proposed to reduce the vehicle's acceleration response for the ride comfort of passengers.

  20. Vibration analysis of continuous maglev guideways with a moving distributed load model

    International Nuclear Information System (INIS)

    Teng, N G; Qiao, B P

    2008-01-01

    A model of moving distributed load with a constant speed is established for vertical vibration analysis of a continuous guideway in maglev transportation system. The guideway is considered as a continuous structural system and the action of maglev vehicles on guideways is considered as a moving distributed load. Vibration of the continuous guideways used in Shanghai maglev line is analyzed with this model. The factors that affect the vibration of the guideways, such as speeds, guideway's spans, frequency and damping, are discussed

  1. Expansion joint for guideway for magnetic levitation transportation system

    Science.gov (United States)

    Rossing, T.D.

    1993-02-09

    An expansion joint that allows a guideway of a magnetic levitation transportation system to expand and contract while minimizing transients occurring in the magnetic lift and drag forces acting on a magnetic levitation vehicle traveling over the joint includes an upper cut or recess extending downwardly from the upper surface of the guideway and a non-intersecting lower cut or recess that extends upwardly from the lower surface of the guideway. The side walls of the cuts can be parallel to each other and the vertical axis of the guideway; the depth of the lower cut can be greater than the depth of the upper cut; and the overall combined lengths of the cuts can be greater than the thickness of the guideway from the upper to lower surface so that the cuts will overlap, but be spaced apart from each other. The distance between the cuts can be determined on the basis of the force transients and the mechanical behavior of the guideway. A second pair of similarly configured upper and lower cuts may be disposed in the guideway; the expansion joint may consist of two upper cuts and one lower cut; or the cuts may have non-parallel, diverging side walls so that the cuts have a substantially dove-tail shape.

  2. Vibration analysis of continuous maglev guideways with a moving distributed load model

    Energy Technology Data Exchange (ETDEWEB)

    Teng, N G; Qiao, B P [Department of Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 (China)

    2008-02-15

    A model of moving distributed load with a constant speed is established for vertical vibration analysis of a continuous guideway in maglev transportation system. The guideway is considered as a continuous structural system and the action of maglev vehicles on guideways is considered as a moving distributed load. Vibration of the continuous guideways used in Shanghai maglev line is analyzed with this model. The factors that affect the vibration of the guideways, such as speeds, guideway's spans, frequency and damping, are discussed.

  3. System Operations Studies for Automated Guideway Transit Systems : Discrete Event Simulation Model Programmer's Manual

    Science.gov (United States)

    1982-07-01

    In order to examine specific automated guideway transit (AGT) developments and concepts, UMTA undertook a program of studies and technology investigations called Automated Guideway Transit Technology (AGTT) Program. The objectives of one segment of t...

  4. Fixed-Guideway Transit Stations (National) - National Geospatial Data Asset (NGDA) Transit (Stations)

    Data.gov (United States)

    Department of Transportation — Version 2004 of the Fixed-Guideway Transit Network is a network database of the nation's fixed-guideway transit systems (NTAD). The data set covers systems in cities...

  5. Fixed-Guideway Transit Lines (National) - National Geospatial Data Asset (NGDA) Transit (Lines)

    Data.gov (United States)

    Department of Transportation — Version 2004 of the Fixed-Guideway Transit Network is a network database of the nation's fixed-guideway transit systems (NTAD). The data set covers systems in cities...

  6. 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...

  7. 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...

  8. 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.

  9. Coupled vibration analysis of Maglev vehicle-guideway while standing still or moving at low speeds

    Science.gov (United States)

    Kim, Ki-Jung; Han, Jong-Boo; Han, Hyung-Suk; Yang, Seok-Jo

    2015-04-01

    Dynamic instability, that is, resonance, may occur on an electromagnetic suspension-type Maglev that runs over the elevated guideway, particularly at very low speeds, due to the flexibility of the guideway. An analysis of the dynamic interaction between the vehicle and guideway is required at the design stage to investigate such instability, setting slender guideway in design direction for reducing construction costs. In addition, it is essential to design an effective control algorithm to solve the problem of instability. In this article, a more detailed model for the dynamic interaction of vehicle/guideway is proposed. The proposed model incorporates a 3D full vehicle model based on virtual prototyping, flexible guideway by a modal superposition method and levitation electromagnets including feedback controller into an integrated model. By applying the proposed model to an urban Maglev vehicle newly developed for commercial application, an analysis of the instability phenomenon and an investigation of air gap control performance are carried out through a simulation.

  10. Dynamic response analysis of single-span guideway caused by high speed maglev train

    Directory of Open Access Journals (Sweden)

    Jin Shi

    Full Text Available High speed maglev is one of the most important reformations in the ground transportation systems because of its no physical contact nature. This paper intends to study the dynamic response of the single-span guideway induced by moving maglev train. The dynamic model of the maglev train-guideway system is established. In this model, a maglev train consists of three vehicles and each vehicle is regarded as a multibody system with 34 degrees-of-freedom. The guideway is modeled as a simply supported beam. Considering the motion-dependent nature of electromagnetic forces in the maglev system, an iterative approach is presented to compute the dynamic response of a maglev train-guideway system. The histories of the train traversing the guideways are simulated and the dynamic responses of the guideway and the train vehicles are calculated. A field experiment is carried out to verify the results of the analysis. The resonant conditions of single-span guideway are analyzed. The results show that all the dynamic indexes of train-guideway system are far less than permissive values of railway and maglev system, the vertical resonant of guideways caused by periodical excitations of the train will not happen.

  11. 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 ...

  12. Effect of lateral deformations of guideway on guidance characteristics of maglev train

    International Nuclear Information System (INIS)

    Kim, Ki Jung; Yang, Seok Jo; Lee, Jae Kyoung; Han, Hyung Suk

    2015-01-01

    A slender guideway is essential in improving aesthetically and reducing its construction cost which accounts for about 70% of overall investment for maglev system. As the slender guideway, however, may increase its deformation, its effect on levitation stability and guidance performance needs to be analyzed. The purpose of this study is to analyze the effect on guidance characteristics of maglev due to the lateral deformation of the guideway girder and lateral irregularity of guiderail. For doing this, 3D model considering lateral deformation of girder and irregularity of rail of the guideway is developed. Using the dynamic interaction model integrated with the proposed guideway and maglev vehicle including electromagnetics and its controller, guidance characteristics of maglev are analyzed. It is analyzed that the effect on lateral deformation of girder is relatively small compared to deformation on the lateral irregularities of guiderail

  13. Effect of lateral deformations of guideway on guidance characteristics of maglev train

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Jung; Yang, Seok Jo [Dept. of Mechatronics Engineering, Chungnam National Unversity, Daejeon (Korea, Republic of); Lee, Jae Kyoung; Han, Hyung Suk [Korea Institute of Machery and Materials, Daejeon (Korea, Republic of)

    2015-11-15

    A slender guideway is essential in improving aesthetically and reducing its construction cost which accounts for about 70% of overall investment for maglev system. As the slender guideway, however, may increase its deformation, its effect on levitation stability and guidance performance needs to be analyzed. The purpose of this study is to analyze the effect on guidance characteristics of maglev due to the lateral deformation of the guideway girder and lateral irregularity of guiderail. For doing this, 3D model considering lateral deformation of girder and irregularity of rail of the guideway is developed. Using the dynamic interaction model integrated with the proposed guideway and maglev vehicle including electromagnetics and its controller, guidance characteristics of maglev are analyzed. It is analyzed that the effect on lateral deformation of girder is relatively small compared to deformation on the lateral irregularities of guiderail.

  14. Guideways for high speed magnetically levitated train systems - TRANSRAPID

    Energy Technology Data Exchange (ETDEWEB)

    Falkner, H [Technische Univ. Braunschweig (Germany); Grossert, E [IBF Dr. Falkner GmbH, Braunschweig/Berlin (Germany)

    1996-12-31

    The superspeed maglev system Transrapid is a rapid train system designed for speeds ranging from 300 to 500 km/h, using new no-contact levitation, guidance and propulsion system technologies, which will soon be used for an actual operational line. On the Transrapid Test Facility in Emsland (TVE), suitibility studies have been carried out since 1984. In 1989, work began on the plans for a reference line. Different guideway constructions, designed for the actual operational line are discussed in the following article. (orig.)

  15. Systems Operations Studies for Automated Guideway Transit Systems : Discrete Event Simulation Model User's Manual.

    Science.gov (United States)

    1982-06-01

    In order to examine specific Automated Guideway Transit (AGT) developments and concepts, and to build a better knowledge base for future decision-making, the Urban Mass Transportation Administration (UMTA) undertook a new program of studies and techn...

  16. 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...

  17. 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...

  18. 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...

  19. Evaluation of ride-quality and incidence of seasickness. 4. Motion sickness incidence and change of facial expression; Senpaku no norigokochi hyoka ni kansuru kenkyu ( 4 ). Norimonoyoi hasshoji no hyojo no henka

    Energy Technology Data Exchange (ETDEWEB)

    Arima, M.; Hirai, T.; Hosoda, R. [Osaka City Univ. (Japan)

    1998-12-31

    This paper studies the method of predicting and evaluating the motion sickness incidence from subject`s facial expressions during the whole-body exposure to oscillations. The facial expressions are recorded with a video camera which can measure them without invasion physiologically and mentally. Facial parameters, which are considered to relate to the motion sickness incidence, are selected, measured and analyzed quantitatively, and a method of evaluating the motion sickness incidence objectively from the facial expressions is proposed. Three facial expression parameters now selected to evaluate the motion sickness incidence are brow width, eye opening and mouth opening. It was clarified that the motion sickness incidence could be expressed joining the above parameters together. This paper consists of three sections, viz. Oscillation experiment for ride-quality evaluation, Measurement and analysis of facial expressions, and Modeling for evaluating facial expressions. 11 refs., 5 figs., 5 tabs.

  20. 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

  1. Maglev guideway route alignment and right-of-way requirements

    Science.gov (United States)

    Carlton, S.; Andriola, T.

    1992-12-01

    The use of existing rights-of-way (ROW) is assessed for maglev systems by estimating trip times and land acquisition requirements for potential maglev corridors while meeting passenger comfort limits. Right-of-way excursions improve trip time but incur a cost for purchasing land. The final report documents findings of the eight tasks in establishing right-of-way feasibility by examining three city-pair corridors in detail and developing an approximation method for estimating route length and travel times in 20 additional city-pair corridor portions and 21 new corridors. The use of routes independent of existing railroad or highway right-of-way have trip time advantages and significantly reduce the need for aggressive guideway geometries on intercity corridors. Selection of the appropriate alignment is determined by many corridor specific issues. Use of existing intercity rights-of-way may be appropriate for parts of routes on a corridor-specific basis and for urban penetration where vehicle speeds are likely to be reduced by policy due to noise and safety considerations, and where land acquisition costs are high. Detailed aspects of available rights-of-way, land acquisition costs, geotechnical issues, land use, and population centers must be examined in more detail on a specific corridor basis before the proper or best maglev alignment can be chosen.

  2. Electrodynamics of finite width guideway maglev systems in an integral equation formulation

    Energy Technology Data Exchange (ETDEWEB)

    Urankar, L [Siemens A.G., Erlangen (Germany, F.R.). Forschungslaboratorium

    1979-01-01

    A completely general, system-independent integral equation for the eddy current density is used to study the electrodynamics of finite guideway repulsive magleydsymaglev systems. For the first time a comparison of the transverse force measurements on a large-scale prototype vehicle (EET) with the theory is presented. The lateral displacement of the excitation magnet produces destabilizing transverse forces. The finite width of the guideway reduces the lift and increases the specific losses. The consequence is that for a given magnet width an adequate guideway overhang beyond the magnet width must be provided, so as not to suffer loss in the lift due to transverse edge effects and keep the lateral destabilizing force small.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. 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,…

  9. "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…

  10. 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…

  11. 36 CFR 1192.173 - Automated guideway transit vehicles and systems.

    Science.gov (United States)

    2010-07-01

    .... Vertical alignment may be accomplished by vehicle air suspension or other suitable means of meeting the... vehicles and systems. 1192.173 Section 1192.173 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.173 Automated guideway transit vehicles and systems. (a...

  12. 49 CFR 38.173 - Automated guideway transit vehicles and systems.

    Science.gov (United States)

    2010-10-01

    ... accomplished by vehicle air suspension or other suitable means of meeting the requirement. (c) In stations... 49 Transportation 1 2010-10-01 2010-10-01 false Automated guideway transit vehicles and systems... DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 38...

  13. Safety of High Speed Magnetic Levitation Transportation Systems : Thermal Effects and Related Safety Issues of Typical Maglev Steel Guideways

    Science.gov (United States)

    1994-09-01

    This report presents a theoretical analysis predicting the temperature distribution, thermal deflections, and thermal stresses that may occur in typical steel Maglev guideways under the proposed Orlando FL thermal environment. Transient, finite eleme...

  14. [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.

  15. 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.

  16. Lift, drag, and guidance forces on alternating polarity magnets, using loop guideways

    International Nuclear Information System (INIS)

    Lindenbaum, S.D.; Lee, M.S.

    1975-01-01

    Exact solutions of track current, lift force, and drag force, together with their velocity dependence, have been computed for a vehicle carrying a finite number of fixed current alternating polarity superconducting magnets, suspended at various heights over structured track guideways of the single- and double-loop (''null'') types. Results for the double-loop case are compared with those of a previously reported approximate analysis. The analytical method is then applied to a study of a low-drag guidance loop guideway which is integrable with lift loop guideways utilizing a common set of vehicle magnets. Solutions are obtained for guidance track restoring forces, lateral destabilization forces, and lift force degradation as functions of lateral displacement from symmetry. The dependence of lift, drag, and lift-to-drag on track loop parameters is studied and the linear dependence of lift-to-drag on loop time constant confirmed. The contribution to the forces made by successive addition of alternating polarity magnets is calculated and the marked reduction in lift force pulsation noted

  17. 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.

  18. 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.

  19. 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…

  20. 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...

  1. Influence of AC external magnetic field on guidance force relaxation between HTS bulk and NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Longcai [Applied Superconductivity Laboratory, P.O. Box 152, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)], E-mail: zhlcai2000@163.com; Wang Suyu; Wang Jiasu; Zheng Jun [Applied Superconductivity Laboratory, P.O. Box 152, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2007-12-01

    Superconducting maglev vehicle is one of the most promising applications of HTS bulks. In such a system, the HTS bulks are always exposed to time-varying external magnetic field, which is generated by the inhomogeneous surface magnetic field of the NdFeB guideway. So it is required to study whether the guidance force of the bulks is influenced by the inhomogeneity. In this paper, we studied the characteristics of the guidance force relaxation between the HTS bulk and the NdFeB guideway by an experiment in which AC external magnetic field generated by an electromagnet was used to simulate the time-varying external magnetic field caused by the inhomogeneity of the guideway. From the experiment results, it was found that the guidance force was decreased with the application of the AC external magnetic field, and the decay increased with the amplitude and was almost independent of the frequency.

  2. 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...

  3. 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.

  4. Vibrational Properties of High- Superconductors Levitated Above a Bipolar Permanent Magnetic Guideway

    Science.gov (United States)

    Liu, Lu; Wang, Jiasu

    2014-05-01

    A bipolar permanent magnetic guideway (PMG) has a unique magnetic field distribution profile which may introduce a better levitation performance and stability to the high- superconducting (HTS) maglev system. The dynamic vibration properties of multiple YBCO bulks arranged into different arrays positioned above a bipolar PMG and free to levitate were investigated. The acceleration and resonance frequencies were experimentally measured, and the stiffness and damping coefficients were evaluated for dynamic stability. Results indicate that the levitation stiffness is closely related to the field-cooling-height and sample positioning. The damping ratio was found to be low and nonlinear for the Halbach bipolar HTS-PMG system.

  5. PrivateRide: A Privacy-Enhanced Ride-Hailing Service

    Directory of Open Access Journals (Sweden)

    Pham Anh

    2017-04-01

    Full Text Available In the past few years, we have witnessed a rise in the popularity of ride-hailing services (RHSs, an online marketplace that enables accredited drivers to use their own cars to drive ride-hailing users. Unlike other transportation services, RHSs raise significant privacy concerns, as providers are able to track the precise mobility patterns of millions of riders worldwide. We present the first survey and analysis of the privacy threats in RHSs. Our analysis exposes high-risk privacy threats that do not occur in conventional taxi services. Therefore, we propose PrivateRide, a privacy-enhancing and practical solution that offers anonymity and location privacy for riders, and protects drivers’ information from harvesting attacks. PrivateRide lowers the high-risk privacy threats in RHSs to a level that is at least as low as that of many taxi services. Using real data-sets from Uber and taxi rides, we show that PrivateRide significantly enhances riders’ privacy, while preserving tangible accuracy in ride matching and fare calculation, with only negligible effects on convenience. Moreover, by using our Android implementation for experimental evaluations, we show that PrivateRide’s overhead during ride setup is negligible. In short, we enable privacy-conscious riders to achieve levels of privacy that are not possible in current RHSs and even in some conventional taxi services, thereby offering a potential business differentiator.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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)

  14. 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...

  15. 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…

  16. A review of dynamic characteristics of magnetically levitated vehicle systems

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Y.; Chen, S.S.

    1995-11-01

    The dynamic response of magnetically levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. Ride quality is determined by vehicle response and by environmental factors such as humidity and noise. The dynamic response of the vehicles is the key element in determining ride quality, while vehicle stability is an important safety-related element. To design a guideway that provides acceptable ride quality in the stable region, vehicle dynamics must be understood. Furthermore, the trade-off between guideway smoothness and levitation and control systems must be considered if maglev systems are to be economically feasible. The link between the guideway and the other maglev components is vehicle dynamics. For a commercial maglev system, vehicle dynamics must be analyzed and tested in detail. This report, which reviews various aspects of the dynamic characteristics, experiments and analysis, and design guidelines for maglev systems, discusses vehicle stability, motion dependent magnetic force components, guideway characteristics, vehicle/ guideway interaction, ride quality, suspension control laws, aerodynamic loads and other excitations, and research needs.

  17. [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.

  18. Wave passage effects on the seismic response of a maglev vehicle moving on multi-span guideway

    Directory of Open Access Journals (Sweden)

    J. D. Yau

    Full Text Available As a seismic wave travels along the separate supports of an extended structure, the structure is subjected to multiple-support excitation due to seismic wave propagation. Considering the seismic wave passage effect, this paper describes seismic analysis of a maglev vehicle moving on a multiply supported gudieway. The guideway system is modeled as a series of simple beams and the vehicle as a four degrees-of-freedom (DOFs rigid bar equipped with multiple onboard PI+LQR hybrid controllers. The controller is used to regulate control voltage for tuning both magnetic forces of uplift levitation and lateral guidance in the maglev system. Numerical studies show that as a maglev vehicle is equipped with more supported magnets then they can provide more control gains for tuning the guidance forces of the moving vehicle, and mitigate seismic-induced lateral vibration of a maglev vehicle running a guideway.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. Magnetic superelevation design of Halbach permanent magnet guideway for high-temperature superconducting maglev

    Science.gov (United States)

    Lei, Wuyang; Qian, Nan; Zheng, Jun; Huang, Huan; Zhang, Ya; Deng, Zigang

    2017-07-01

    To improve the curve negotiating ability of high-temperature superconducting (HTS) maglev system, a special structure of magnetic superelevation for double-pole Halbach permanent magnet guideway (PMG) was designed. The most significant feature of this design is the asymmetrical PMG that forms a slanting magnetic field without affecting the smoothness of the PMG surface. When HTS maglev vehicle runs through curves with magnetic superelevation, the vehicle will slant due to asymmetry in magnetic field and the flux-pinning effect of onboard HTS bulks. At the same time, one component of the levitation force provides a part of the centripetal force that reduces lateral acceleration of the vehicle and thus enhances its curve negotiating ability. Furthermore, the slant angle of magnetic superelevation can be adjusted by changing the materials and the thickness of the added permanent magnets. This magnetic superelevation method, together with orographic uplift, can be applied to different requirements of PMG designs. Besides, the applicability of this method would benefit future development of high-speed HTS maglev system.

  6. A two-pole Halbach permanent magnet guideway for high temperature superconducting Maglev vehicle

    International Nuclear Information System (INIS)

    Jing, H.; Wang, J.; Wang, S.; Wang, L.; Liu, L.; Zheng, J.; Deng, Z.; Ma, G.; Zhang, Y.; Li, J.

    2007-01-01

    In order to improve the levitation performance of the high temperature superconducting (HTS) magnetic levitation (Maglev) vehicle, a two-pole Halbach array's permanent magnet guideway (PMG) is proposed, which is called as Halbach PMG. The finite element method (FEM) calculations indicate that Halbach PMG has a wider high-field region than the present PMG of equal PM's transverse section. The levitation force of bulk HTSCs with the present PMG and Halbach PMG are measured. The results show that at different levitation gaps, the force ratios based on the Halbach PMG are about 2.3 times larger than that on the present PMG, which greatly increases the load capability of the system. Therefore, both the numerical analysis and experimental results have confirmed that the Halbach PMG will further enhance the performance of the vehicle and it is possible to decrease the total numbers of onboard HTSCs, reducing overall costs. So based on the Halbach PMG, we further study the width ratios between HTSCs and PMG for making the better use of the onboard HTSCs. Some preliminary results are given. These results are important for further HTS Maglev vehicle system designs using Halbach PMG

  7. Maglev performance of a double-layer bulk high temperature superconductor above a permanent magnet guideway

    International Nuclear Information System (INIS)

    Deng, Z; Wang, J; Zheng, J; Lin, Q; Zhang, Y; Wang, S

    2009-01-01

    In order to improve the performance of the present high temperature superconducting (HTS) maglev vehicle system, the maglev performance of single- and double-layer bulk high temperature superconductors (HTSC) was investigated above a permanent magnet guideway (PMG). It is found that the maglev performance of a double-layer bulk HTSC is not a simple addition of each layer's levitation and guidance force. Moreover, the applied magnetic field at the position of the upper layer bulk HTSC is not completely shielded by the lower layer bulk HTSC either. 53.5% of the levitation force and 27.5% of the guidance force of the upper layer bulk HTSC are excited in the double-layer bulk HTSC arrangement in the applied field-cooling condition and working gap, bringing a corresponding improvement of 16.9% and 8.8% to the conventional single-layer bulk HTSC. The present research implies that the cost performance of upper layer bulk HTSC is a little low for the whole HTS maglev system.

  8. Maglev performance of a double-layer bulk high temperature superconductor above a permanent magnet guideway

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z; Wang, J; Zheng, J; Lin, Q; Zhang, Y; Wang, S [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu, 610031 (China)], E-mail: asclab@asclab.cn

    2009-05-15

    In order to improve the performance of the present high temperature superconducting (HTS) maglev vehicle system, the maglev performance of single- and double-layer bulk high temperature superconductors (HTSC) was investigated above a permanent magnet guideway (PMG). It is found that the maglev performance of a double-layer bulk HTSC is not a simple addition of each layer's levitation and guidance force. Moreover, the applied magnetic field at the position of the upper layer bulk HTSC is not completely shielded by the lower layer bulk HTSC either. 53.5% of the levitation force and 27.5% of the guidance force of the upper layer bulk HTSC are excited in the double-layer bulk HTSC arrangement in the applied field-cooling condition and working gap, bringing a corresponding improvement of 16.9% and 8.8% to the conventional single-layer bulk HTSC. The present research implies that the cost performance of upper layer bulk HTSC is a little low for the whole HTS maglev system.

  9. Correlations Between Magnetic Flux and Levitation Force of HTS Bulk Above a Permanent Magnet Guideway

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Zheng, Botian; Qian, Nan; Li, Haitao; Li, Jipeng; Deng, Zigang

    2017-10-01

    In order to clarify the correlations between magnetic flux and levitation force of the high-temperature superconducting (HTS) bulk, we measured the magnetic flux density on bottom and top surfaces of a bulk superconductor while vertically moving above a permanent magnet guideway (PMG). The levitation force of the bulk superconductor was measured simultaneously. In this study, the HTS bulk was moved down and up for three times between field-cooling position and working position above the PMG, followed by a relaxation measurement of 300 s at the minimum height position. During the whole processes, the magnetic flux density and levitation force of the bulk superconductor were recorded and collected by a multipoint magnetic field measurement platform and a self-developed maglev measurement system, respectively. The magnetic flux density on the bottom surface reflected the induced field in the superconductor bulk, while on the top, it reveals the penetrated magnetic flux. The results show that the magnetic flux density and levitation force of the bulk superconductor are in direct correlation from the viewpoint of inner supercurrent. In general, this work is instructive for understanding the connection of the magnetic flux density, the inner current density and the levitation behavior of HTS bulk employed in a maglev system. Meanwhile, this magnetic flux density measurement method has enriched present experimental evaluation methods of maglev system.

  10. Investigation of the Machining Stability of a Milling Machine with Hybrid Guideway Systems

    Directory of Open Access Journals (Sweden)

    Jui-Pin Hung

    2016-03-01

    Full Text Available This study was aimed to investigate the machining stability of a horizontal milling machine with hybrid guideway systems by finite element method. To this purpose, we first created finite element model of the milling machine with the introduction of the contact stiffness defined at the sliding and rolling interfaces, respectively. Also, the motorized built-in spindle model was created and implemented in the whole machine model. Results of finite element simulations reveal that linear guides with different preloads greatly affect the dynamic responses and machining stability of the horizontal milling machine. The critical cutting depth predicted at the vibration mode associated with the machine tool structure is about 10 mm and 25 mm in the X and Y direction, respectively, while the cutting depth predicted at the vibration mode associated with the spindle structure is about 6.0 mm. Also, the machining stability can be increased when the preload of linear roller guides of the feeding mechanism is changed from lower to higher amount.

  11. 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...

  12. Influence of shape and thickness on the levitation force of YBaCuO bulk HTS over a NdFeB guideway

    International Nuclear Information System (INIS)

    Ren Zhongyou; Wang Jiasu; Wang Suyu; Jiang He; Zhu Min; Wang Xiaorong; Song Honghai

    2003-01-01

    Levitation forces of YBaCuO bulk high temperature superconductors (HTS) with different shape and size over a NdFeB guideway were studied. Here, the concentrating magnetic field of the NdFeB guideway was 1.2 T, and the YBaCuO bulk HTSs include three cylindrical samples with different diameter and thickness and one hexagonal sample. The maximum levitation force is as high as 85.3 N at a gap of 5 mm between the bottom surface of YBaCuO bulk HTS and the top surface of the NdFeB guideway, where the applied magnetic field is about 0.8 T. The results show that the shape and the size have large influences on the levitation force of YBaCuO bulk HTSs

  13. 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…

  14. 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...

  15. 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...

  16. 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…

  17. 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...

  18. The influence of inhomogeneous magnetic field over a NdFeB guideway on levitation force of the HTS bulk maglev system

    Science.gov (United States)

    Zhao, Lifeng; Deng, Jiangtao; Li, Linbo; Feng, Ning; Wei, Pu; Lei, Wei; Jiang, Jing; Wang, Xiqin; Zhang, Yong; Zhao, Yong

    2018-04-01

    Dynamic responses of high temperature superconducting bulk to inhomogeneous magnetic field distribution of permanent magnet guideway, as well as enlarged amplitude of magnetic field obtained by partially covering the permanent magnet guideway (PMG) with iron sheets in different thickness, are investigated. Experiments show that the instantaneous levitation force increases with the increase of the variation rate of magnetic field (dB/dt). Meanwhile, inhomogeneous magnetic field from PMG causes the decay of levitation force. The decay of levitation force almost increases linearly with the increase of alternating magnetic field amplitude. It should be very important for the application of high-speed maglev system.

  19. 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.

  20. 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

  1. Influence of AC external magnetic field perturbation on the guidance force of HTS bulk over a NdFeB guideway

    International Nuclear Information System (INIS)

    Zhang Longcai; Wang Jiasu; Wang Suyu; He Qingyong

    2007-01-01

    Superconducting maglev vehicle system requires that the surface magnetic field of the guideway is uniform along the forward direction. But in practice the surface magnetic field of the NdFeB permanent magnet guideway is not always immutable. So the HTS bulks in this case are exposed to AC external magnetic field, which may induce the energy loss in the bulk and influence the guidance force between the HTS bulks and the NdFeB guideway. In this paper, we experimentally studied the influence of the AC external magnetic field perturbation on the guidance force of a HTS bulk over the NdFeB guideway. The experimental results showed that the guidance force was influenced by the application of the AC external magnetic. The guidance fore hysteresis became more evident with the amplitude of the AC field and was independent of the frequency in the range 90-400 Hz. We attributed the reason to magnetic hysteresis loss in the superconductor

  2. Influence of AC external magnetic field perturbation on the guidance force of HTS bulk over a NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Longcai [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)]. E-mail: zhlcai2000@163.com; Wang Jiasu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China); Wang Suyu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China); He Qingyong [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)

    2007-08-01

    Superconducting maglev vehicle system requires that the surface magnetic field of the guideway is uniform along the forward direction. But in practice the surface magnetic field of the NdFeB permanent magnet guideway is not always immutable. So the HTS bulks in this case are exposed to AC external magnetic field, which may induce the energy loss in the bulk and influence the guidance force between the HTS bulks and the NdFeB guideway. In this paper, we experimentally studied the influence of the AC external magnetic field perturbation on the guidance force of a HTS bulk over the NdFeB guideway. The experimental results showed that the guidance force was influenced by the application of the AC external magnetic. The guidance fore hysteresis became more evident with the amplitude of the AC field and was independent of the frequency in the range 90-400 Hz. We attributed the reason to magnetic hysteresis loss in the superconductor.

  3. 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...

  4. Superconducting bulk magnet for maglev vehicle: Stable levitation performance above permanent magnet guideway

    International Nuclear Information System (INIS)

    Deng, Z.; Zheng, J.; Li, J.; Ma, G.; Lu, Y.; Zhang, Y.; Wang, S.; Wang, J.

    2008-01-01

    High-temperature superconducting (HTS) maglev vehicle is well known as one of the most potential applications of bulk high-temperature superconductors (HTSCs) in transported levitation system. Many efforts have promoted the practice of the HTS maglev vehicle in people's life by enhancing the load capability and stability. Besides improving the material performance of bulk HTSC and optimizing permanent magnet guideway (PMG), magnetization method of bulk HTSC is also very effective for more stable levitation. Up to now, applied onboard bulk HTSCs are directly magnetized by field cooling above the PMG for the present HTS maglev test vehicles or prototypes in China, Germany, Russia, Brazil, and Japan. By the direct-field-cooling-magnetization (DFCM) over PMG, maglev performances of the bulk HTSCs are mainly depended on the PMG's magnetic field. However, introducing HTS bulk magnet into the HTS maglev system breaks this dependence, which is magnetized by other non-PMG magnetic field. The feasibility of this HTS bulk magnet for maglev vehicle is investigated in the paper. The HTS bulk magnet is field-cooling magnetized by a Field Control Electromagnets Workbench (FCEW), which produces a constant magnetic field up to 1 T. The levitation and guidance forces of the HTS bulk magnet over PMG with different trapped flux at 15 mm working height (WH) were measured and compared with that by DFCM in the same applied PMG magnetic field at optimal field-cooling height (FCH) 30 mm, WH 15 mm. It is found that HTS bulk magnet can also realize a stable levitation above PMG. The trapped flux of HTS bulk magnet is easily controllable by the charging current of FCEW, which implies the maglev performances of HTS bulk magnet above PMG will be adjustable according to the practical requirement. The more trapped flux HTS bulk magnet will lead to bigger guidance force and smaller repulsion levitation force above PMG. In the case of saturated trapped flux for experimental HTS bulk magnet, it is

  5. Superconducting bulk magnet for maglev vehicle: Stable levitation performance above permanent magnet guideway

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z.; Zheng, J.; Li, J.; Ma, G.; Lu, Y.; Zhang, Y.; Wang, S. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Wang, J. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: jsywang@home.swjtu.edu.cn

    2008-06-15

    High-temperature superconducting (HTS) maglev vehicle is well known as one of the most potential applications of bulk high-temperature superconductors (HTSCs) in transported levitation system. Many efforts have promoted the practice of the HTS maglev vehicle in people's life by enhancing the load capability and stability. Besides improving the material performance of bulk HTSC and optimizing permanent magnet guideway (PMG), magnetization method of bulk HTSC is also very effective for more stable levitation. Up to now, applied onboard bulk HTSCs are directly magnetized by field cooling above the PMG for the present HTS maglev test vehicles or prototypes in China, Germany, Russia, Brazil, and Japan. By the direct-field-cooling-magnetization (DFCM) over PMG, maglev performances of the bulk HTSCs are mainly depended on the PMG's magnetic field. However, introducing HTS bulk magnet into the HTS maglev system breaks this dependence, which is magnetized by other non-PMG magnetic field. The feasibility of this HTS bulk magnet for maglev vehicle is investigated in the paper. The HTS bulk magnet is field-cooling magnetized by a Field Control Electromagnets Workbench (FCEW), which produces a constant magnetic field up to 1 T. The levitation and guidance forces of the HTS bulk magnet over PMG with different trapped flux at 15 mm working height (WH) were measured and compared with that by DFCM in the same applied PMG magnetic field at optimal field-cooling height (FCH) 30 mm, WH 15 mm. It is found that HTS bulk magnet can also realize a stable levitation above PMG. The trapped flux of HTS bulk magnet is easily controllable by the charging current of FCEW, which implies the maglev performances of HTS bulk magnet above PMG will be adjustable according to the practical requirement. The more trapped flux HTS bulk magnet will lead to bigger guidance force and smaller repulsion levitation force above PMG. In the case of saturated trapped flux for experimental HTS bulk

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  12. Inhomogeneity of surface magnetic field over a NdFeB guideway and its influence on levitation force of the HTS bulk maglev system

    International Nuclear Information System (INIS)

    Zhang, Longcai; Wang Jiasu; He Qingyong; Zhang Jianghua; Wang Suyu

    2007-01-01

    Superconducting maglev vehicle system was one of the most promising applications of HTS bulks. The NdFeB guideway in this system was composed of many NdFeB permanent magnets and screws, so the air gaps (airgaps) between two permanent magnets and the screws would result in the inhomogeneity of the surface magnetic field. In this paper, we studied the magnetic inhomogeneity over the permanent magnet guideway (PMG) used in high-temperature superconducting (HTS) maglev vehicle system and its influence on the levitation force of the HTS bulk. Firstly, we measured the transverse magnetic field above the airgap, the screw and the place under where there was no airgap and screw. It was found that the magnetic field 10 mm above the guideway was roughly uniform. Secondly, we investigated the influence of the magnetic inhomogeneity of the PMG on levitation force of the bulk superconductor. From the experiment results, we found that the influence was very small, and would be ignored. Therefore, we could conclude that the PMG made by this method satisfied the requirements of the HTS maglev vehicle system in a quasi-static state

  13. Inhomogeneity of surface magnetic field over a NdFeB guideway and its influence on levitation force of the HTS bulk maglev system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Longcai [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu 610031 (China)]. E-mail: zhlcai2000@163.com; Wang Jiasu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu 610031 (China); He Qingyong [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu 610031 (China); Zhang Jianghua [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu 610031 (China); Wang Suyu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu 610031 (China)

    2007-08-01

    Superconducting maglev vehicle system was one of the most promising applications of HTS bulks. The NdFeB guideway in this system was composed of many NdFeB permanent magnets and screws, so the air gaps (airgaps) between two permanent magnets and the screws would result in the inhomogeneity of the surface magnetic field. In this paper, we studied the magnetic inhomogeneity over the permanent magnet guideway (PMG) used in high-temperature superconducting (HTS) maglev vehicle system and its influence on the levitation force of the HTS bulk. Firstly, we measured the transverse magnetic field above the airgap, the screw and the place under where there was no airgap and screw. It was found that the magnetic field 10 mm above the guideway was roughly uniform. Secondly, we investigated the influence of the magnetic inhomogeneity of the PMG on levitation force of the bulk superconductor. From the experiment results, we found that the influence was very small, and would be ignored. Therefore, we could conclude that the PMG made by this method satisfied the requirements of the HTS maglev vehicle system in a quasi-static state.

  14. 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...

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

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

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

  16. 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

  17. 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,…

  18. 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...

  19. 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

  20. 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 ...

  1. 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…

  2. Tire safety : everything rides on it

    Science.gov (United States)

    2008-01-01

    This booklet presents a comprehensive overview of tire safety, including information on the following topics: basic tire maintenance; Uniform Tire Quality Grading System; fundamental characteristics of tires; and tire safety tips.

  3. Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

    Science.gov (United States)

    Wang, B.; Zheng, J.; Che, T.; Zheng, B. T.; Si, S. S.; Deng, Z. G.

    2015-12-01

    The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

  4. Comprehensive comparison of the levitation performance of bulk YBaCuO arrays above two different types of magnetic guideways

    International Nuclear Information System (INIS)

    Deng, Zigang; Qian, Nan; Che, Tong; Jin, Liwei; Si, Shuaishuai; Zhang, Ya; Zheng, Jun

    2016-01-01

    The permanent magnet guideway (PMG) is an important part of high temperature superconducting (HTS) maglev systems. So far, two types of PMG, the normal PMG and Halbach-type PMG, are widely applied in present maglev transportation systems. In this paper, the levitation performance of high temperature superconductor bulks above the two PMGs was synthetically compared. Both static levitation performance and dynamic response characteristics were investigated. Benefiting from the reasonable magnetic field distribution, the Halbach-type PMG is able to gain larger levitation force, greater levitation force decay during the same relaxation time, bigger resonance frequency and dynamic stiffness for the bulk superconductor levitation unit compared with the normal PMG. Another finding is that the Halbach-type PMG is not sensitive to the levitation performance of the bulk levitation unit with different arrays. These results are helpful for the practical application of HTS maglev systems. - Highlights: • The effect of PMG configurations to levitation performances is investigated. • Bigger force and greater force decay are obtained on Halbach-type PMG. • Halbach-type PMG is not sensitive to the levitation force in various bulk arrays. • Practical issues including costs and assembly of PMGs are considered.

  5. Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

    International Nuclear Information System (INIS)

    Wang, B.; Zheng, J.; Che, T.; Zheng, B.T.; Si, S.S.; Deng, Z.G.

    2015-01-01

    Highlights: • The loading weight affects the RF tremendously. • Reducing the FCH can improve the stability of the maglev vehicle. • The Halbach-type PMG has better loading capacity than the conventional PMG. • Pre-load is an effective way to enhance the dynamic characteristic of the HTS maglev vehicle. - Abstract: The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

  6. Comprehensive comparison of the levitation performance of bulk YBaCuO arrays above two different types of magnetic guideways

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zigang, E-mail: deng@swjtu.cn [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, 610031 (China); Qian, Nan; Che, Tong; Jin, Liwei [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, 610031 (China); Si, Shuaishuai [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, 610031 (China); School of Electrical Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); Zhang, Ya; Zheng, Jun [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, 610031 (China)

    2016-12-15

    The permanent magnet guideway (PMG) is an important part of high temperature superconducting (HTS) maglev systems. So far, two types of PMG, the normal PMG and Halbach-type PMG, are widely applied in present maglev transportation systems. In this paper, the levitation performance of high temperature superconductor bulks above the two PMGs was synthetically compared. Both static levitation performance and dynamic response characteristics were investigated. Benefiting from the reasonable magnetic field distribution, the Halbach-type PMG is able to gain larger levitation force, greater levitation force decay during the same relaxation time, bigger resonance frequency and dynamic stiffness for the bulk superconductor levitation unit compared with the normal PMG. Another finding is that the Halbach-type PMG is not sensitive to the levitation performance of the bulk levitation unit with different arrays. These results are helpful for the practical application of HTS maglev systems. - Highlights: • The effect of PMG configurations to levitation performances is investigated. • Bigger force and greater force decay are obtained on Halbach-type PMG. • Halbach-type PMG is not sensitive to the levitation force in various bulk arrays. • Practical issues including costs and assembly of PMGs are considered.

  7. High-efficiency and low-cost permanent magnet guideway consideration for high-Tc superconducting Maglev vehicle practical application

    International Nuclear Information System (INIS)

    Deng, Z; Wang, J; Zheng, J; Jing, H; Lu, Y; Ma, G; Liu, L; Liu, W; Zhang, Y; Wang, S

    2008-01-01

    In order to improve the cost performance of the present high-T c superconducting (HTS) Maglev vehicle system for practical application, the multi-pole permanent magnet guideway (PMG) concept was introduced. A well-known double-pole Halbach PMG was chosen as a representative of multi-pole PMGs to compare with traditional monopole PMGs from the point of view of levitation efficiency and cost. Experimental results show that YBCO bulks above the double-pole Halbach PMG can exhibit better load capability and guidance performance as well as dynamics stability at the applied working height between the bulk HTSC and the PMG due to a more reasonable magnetic field distribution at the working range of bulk HTSC. Furthermore, the double-pole PMG configuration can play a more important role in improving guidance performance due to the potential-well field configuration. By comparing with former 'century' PMGs, the double-pole Halbach PMG shows another remarkable advantage in reducing the cost of levitation. As another necessary issue, magnetic field homogeneity and the corresponding magnetic drag force of a double-pole Halbach PMG has been considered by experiment in spite of the above highlights. Synthetically, the multi-pole Halbach PMG design is concluded to be one important choice for future HTS Maglev vehicle applications because of its high efficiency and low cost.

  8. Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B. [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P R China (China); Zheng, J., E-mail: jzheng@swjtu.cn [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P R China (China); Che, T. [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P R China (China); Zheng, B.T.; Si, S.S. [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P R China (China); School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, P R China (China); Deng, Z.G., E-mail: deng@swjtu.cn [Applied Superconductivity Laboratory, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P R China (China)

    2015-12-15

    Highlights: • The loading weight affects the RF tremendously. • Reducing the FCH can improve the stability of the maglev vehicle. • The Halbach-type PMG has better loading capacity than the conventional PMG. • Pre-load is an effective way to enhance the dynamic characteristic of the HTS maglev vehicle. - Abstract: The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

  9. The "Ride for Russia" Tree Lichen Survey

    Science.gov (United States)

    Young, Simon

    2013-01-01

    The prevalence of nine indicator lichens found on trees in Northern Europe and Western Russia was used for monitoring air quality. The 4200 mile route of the survey went through eight countries. Surveys were carried out in cities, towns, countryside and forests, and along motorways. The author has conducted tree lichen surveys with pupils from…

  10. 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

  11. 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...

  12. A Concept for the Use and Integration of Super-Conducting Magnets in Structural Systems in General and Maglev Guideway Mega-Structures in Particular

    Science.gov (United States)

    Ussery, Wilfred T.; MacCalla, Eric; MacCalla, Johnetta; Elnimeiri, Mahjoub; Goldsmith, Myron; Polk, Sharon Madison; Jenkins, Mozella; Bragg, Robert H.

    1996-01-01

    Recent breakthroughs in several different fields now make it possible to incorporate the use of superconducting magnets in structures in ways which enhance the performance of structural members or components of structural systems in general and Maglev guideway mega-structures in particular. The building of structural systems which connect appropriately scaled superconducting magnets with the post-tensioned tensile components of beams, girders, or columns would, if coupled with 'state of the art' structure monitoring, feedback and control systems, and advanced computer software, constitute a distinct new generation of structures that would possess the unique characteristic of being heuristic and demand or live-load responsive. The holistic integration of powerful superconducting magnets in structures so that they do actual structural work, creates a class of 'technologically endowed' structures that, in part - literally substitute superconductive electric power and magnetism for concrete and steel. The research and development engineering, and architectural design issues associated with such 'technologically endowed' structural system can now be conceptualized, designed, computer simulates built and tested. The Maglev guideway mega-structure delineated herein incorporates these concepts, and is designed for operation in the median strip of U.S. Interstate Highway 5 from San Diego to Seattle an Vancouver, and possibly on to Fairbanks, Alaska. This system also fits in the median strip of U.S. Interstate Highway 55 and 95 North-South, and 80 and 10, East-West. As a Western Region 'Peace Dividend' project, it could become a National or Bi-National research, design and build, super turnkey project that would create thousands of jobs by applying superconducting, material science, electronic aerospace and other defense industry technologies to a multi-vehicle, multi-use Maglev guideway megastructure that integrates urban mass transit Lower Speed (0-100 mph), High Speed

  13. 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....

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. Riding a tsunami in ocean science education

    Science.gov (United States)

    Reed, Donald L.

    1998-08-01

    An experiment began in late 1994 in which the WWW plays a critical role in the instruction of students in an oceanography course for non-majors. The format of the course consists of an equal blend of traditional lectures, tutorial-style exercises delivered from the course WWW site, classroom activities, such as poster presentations and group projects, and field excursions to local marine environments. The driving force behind the technology component of the course is to provide high-quality educational materials that can be accessed at the convenience of the student. These materials include course information and handouts, lecture notes, self-paced exercises, a virtual library of electronic resources, information on newsworthy marine events, and late-breaking oceanographic research that impacts the population of California. The course format was designed to partially meet the demands of today's students, involve students in the learning process, and prepare students for using technology in work following graduation. Students have reacted favorably to the use of the WWW and comments by peers have been equally supportive. Students are more focused in their efforts during the computer-based exercises than while listening to lecture presentations. The implementation of this form of learning, however, has not, as yet, reduced the financial cost of the course or the amount of instructor effort in providing a high quality education. Interactions between the instructor and students have increased significantly as the informality of a computer laboratory promotes individual discussions and electronic communication provides students with easy (and frequent) access to the instructor outside of class.

  19. 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

  20. 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

  1. Solving the dial-a-ride problem using agent-based simulation

    Directory of Open Access Journals (Sweden)

    Campbell, Ian

    2016-11-01

    Full Text Available The ‘dial-a-ride problem’ (DARP requires a set of customers to be transported by a limited fleet of vehicles between unique origins and destinations under several service constraints, including within defined time windows. The problem is considered NP-hard, and has typically been solved using metaheuristic methods. An agent-based simulation (ABS model was developed, where each vehicle bids to service customers based on a weighted objective function that considers the cost to service the customer and the time quality of the service that would be achieved. The approach applied a pre- processing technique to reduce the search space, given the service time window constraints. Tests of the model showed significantly better customer transit and waiting times than the benchmark datasets. The ABS was able to obtain solutions for much larger problem sizes than the benchmark solutions, with this work being the first known application of ABS to the DARP.

  2. 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

  3. 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.

  4. The attenuation of the levitation force of HTS bulk exposed to AC magnetic field on the above NdFeB guideway

    International Nuclear Information System (INIS)

    Liu Minxian; Wang Yan

    2012-01-01

    The characteristic of the levitation force relaxation was studied by experiment. The levitation force is attenuated with the application of the AC external magnetic field. The decay increases with the amplitude of the A external magnetic field. The decay is almost independent of the frequency of AC field. In the present High Temperature Superconducting (HTS) maglev vehicle system, the air gaps between the adjacent permanent magnets make the magnetic fields above the NdFeB guideway non-uniform. So it is required to study the characteristics of levitation force of the HTS bulk affected by the non-uniform applied magnetic fields along the moving direction. In this paper, we have studied the characteristics of the levitation force relaxation by an experiment in which AC magnetic field generated by an electromagnet is used to simulate the time-varying magnetic field caused by the inhomogeneity of the NdFeB guideway. From the experiment results, it is found that the levitation force is attenuated with the application of the AC field, and the attenuation is increased with the amplitude of the AC field, but the attenuation is almost independent of the frequency the AC magnetic field.

  5. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    International Nuclear Information System (INIS)

    Qin Yujie; Hou Xiaojing

    2011-01-01

    Research highlights: → The relaxation properties of maglev forces have been investigated simultaneously. → Influence of relaxation on forces of HTSC subjected to different LDs above PMG is different. → The influence is explained based on motion of flux lines, re/demagnetization of HTSC during LD. → The work provide a scientific analysis for the practical application of the bulk HTSC. - Abstract: This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  6. The attenuation of the levitation force of HTS bulk exposed to AC magnetic field on the above NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Liu Minxian, E-mail: liukey_sjtu@263.net [School of Computer Science and Technology, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Wang Yan [Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China)

    2012-01-15

    The characteristic of the levitation force relaxation was studied by experiment. The levitation force is attenuated with the application of the AC external magnetic field. The decay increases with the amplitude of the A external magnetic field. The decay is almost independent of the frequency of AC field. In the present High Temperature Superconducting (HTS) maglev vehicle system, the air gaps between the adjacent permanent magnets make the magnetic fields above the NdFeB guideway non-uniform. So it is required to study the characteristics of levitation force of the HTS bulk affected by the non-uniform applied magnetic fields along the moving direction. In this paper, we have studied the characteristics of the levitation force relaxation by an experiment in which AC magnetic field generated by an electromagnet is used to simulate the time-varying magnetic field caused by the inhomogeneity of the NdFeB guideway. From the experiment results, it is found that the levitation force is attenuated with the application of the AC field, and the attenuation is increased with the amplitude of the AC field, but the attenuation is almost independent of the frequency the AC magnetic field.

  7. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Qin Yujie, E-mail: qyjswjtu@vip.sohu.co [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China); Hou Xiaojing [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China)

    2011-02-15

    Research highlights: {yields} The relaxation properties of maglev forces have been investigated simultaneously. {yields} Influence of relaxation on forces of HTSC subjected to different LDs above PMG is different. {yields} The influence is explained based on motion of flux lines, re/demagnetization of HTSC during LD. {yields} The work provide a scientific analysis for the practical application of the bulk HTSC. - Abstract: This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  8. 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.

  9. 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.

  10. 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....

  11. 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.

  12. 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.

  13. 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...

  14. Metaheuristics for the dynamic stochastic dial-a-ride problem with expected return transports.

    Science.gov (United States)

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

    2011-12-01

    The problem of transporting patients or elderly people has been widely studied in literature and is usually modeled as a dial-a-ride problem (DARP). In this paper we analyze the corresponding problem arising in the daily operation of the Austrian Red Cross. This nongovernmental organization is the largest organization performing patient transportation in Austria. The aim is to design vehicle routes to serve partially dynamic transportation requests using a fixed vehicle fleet. Each request requires transportation from a patient's home location to a hospital (outbound request) or back home from the hospital (inbound request). Some of these requests are known in advance. Some requests are dynamic in the sense that they appear during the day without any prior information. Finally, some inbound requests are stochastic. More precisely, with a certain probability each outbound request causes a corresponding inbound request on the same day. Some stochastic information about these return transports is available from historical data. The purpose of this study is to investigate, whether using this information in designing the routes has a significant positive effect on the solution quality. The problem is modeled as a dynamic stochastic dial-a-ride problem with expected return transports. We propose four different modifications of metaheuristic solution approaches for this problem. In detail, we test dynamic versions of variable neighborhood search (VNS) and stochastic VNS (S-VNS) as well as modified versions of the multiple plan approach (MPA) and the multiple scenario approach (MSA). Tests are performed using 12 sets of test instances based on a real road network. Various demand scenarios are generated based on the available real data. Results show that using the stochastic information on return transports leads to average improvements of around 15%. Moreover, improvements of up to 41% can be achieved for some test instances.

  15. 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

  16. 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...

  17. 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...

  18. Relationship of the Levitation Force Between Single and Multiple YBCO Bulks Above a Permanent Magnet Guideway Operating Dive-Lift Movement with Different Angles

    Science.gov (United States)

    Zeng, R.; Wang, S. Y.; Liao, X. L.; Deng, Z. G.; Wang, J. S.

    2013-04-01

    In practical applications, the acceleration and deceleration motions inevitably happen in the operation of high temperature superconducting (HTS) maglev trains. For further research of the maglev properties of YBaCuO bulk above a permanent magnet guideway (PMG), by moving a fixed vertical distance, this paper studies the relationship of the levitation force between single and multiple YBCO bulks above a PMG operating dive-lift movement with different angles. Experimental results show that the maximal levitation force increment of two bulks than one bulk is smaller than the maximal levitation force increment of three bulks than two bulks. With the degree decreasing, the maximal levitation force increment of three bulks is bigger than the maximal levitation force increment of two bulks and one bulk, and the hysteresis loop of the levitation force of the three-bulk arrangement is getting smaller.

  19. Numerical evaluation of guidance force decay of HTS bulk exposed to AC magnetic field over a NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Longcai [P.O. Box 152, Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)], E-mail: zhlcai2000@163.com; Wang Jiasu; Wang Suyu; Zheng Jun; He Qingyong [P.O. Box 152, Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2007-12-01

    The guidance force of the YBCO bulk over a NdFeB guideway used in the high-temperature superconducting maglev vehicle system was decayed by the application of the AC external magnetic field. In our previous work, we explained that the decay was due to the temperature rise of the HTS bulk caused by AC losses. In this paper, we adopted an analytic model to evaluate the decay of the critical current density of the bulk. And based on the analytic results and the Bean critical-state model, we calculated the guidance force as a function of times. Compared with the experimental results, the calculation results have almost the same trend and can qualitatively reveal the characteristics of guidance force of HTS bulk in this situation. Therefore, the guidance force decay of HTS bulk in the maglev vehicle system can be evaluated simply by this numerical method.

  20. 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.

  1. 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.

  2. 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...

  3. Flexible fault ride through strategy for wind farm clusters in power systems with high wind power penetration

    International Nuclear Information System (INIS)

    Wang, Songyan; Chen, Ning; Yu, Daren; Foley, Aoife; Zhu, Lingzhi; Li, Kang; Yu, Jilai

    2015-01-01

    Highlights: • A flexible fault ride through strategy is proposed. • The strategy comprises of grid code requirements and power restrictions. • Slight faults and moderate faults are the main defending objectives. • Temporary overloading capability of the doubly fed induction generator is considered. - Abstract: This paper investigates a flexible fault ride through strategy for power systems in China with high wind power penetration. The strategy comprises of adaptive fault ride through requirements and maximum power restrictions of the wind farms with weak fault ride through capabilities. The slight faults and moderate faults with high probability are the main defending objective of the strategy. The adaptive fault ride through requirement in the strategy consists of two sub fault ride through requirements, a temporary slight voltage ride through requirement corresponding to a slight fault incident, with a moderate voltage ride through requirement corresponding to a moderate fault. The temporary overloading capability of the wind farm is reflected in both requirements to enhance the capability to defend slight faults and to avoid tripping when the crowbar is disconnected after moderate faults are cleared. For those wind farms that cannot meet the adaptive fault ride through requirement, restrictions are put on the maximum power output. Simulation results show that the flexible fault ride through strategy increases the fault ride through capability of the wind farm clusters and reduces the wind power curtailment during faults

  4. 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.

  5. 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...

  6. Capability of DFIG WTS to ride through recurring asymmetrical grid faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Chen, Min

    2014-01-01

    The Wind Turbine Systems (WTS) are required to ride through recurring grid faults in some countries. In this paper, the capability of Doubly Fed Induction Generator (DFIG) WTS to ride through recurring asymmetrical grid faults is evaluated and compared with the ride through capability under single...... asymmetrical grid fault. A mathematical model of the DFIG under recurring asymmetrical grid faults is represented. The analysis are verified by simulations on a 1.5MW DFIG model and by experiments on a reduced-scale DFIG test system....

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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 ...

  12. 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...

  13. 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.)

  14. 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...

  15. 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

  16. 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

  17. Fault ride-through and voltage support of permanent magnet synchronous generator wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Michalke, G.; Hartkopf, T. [Darmstadt Technical Univ., Dept. of Renewable Energies (Germany); Hansen, A.D. [Risoe National Lab., DTU, Wind Energy Dept. (Denmark)

    2007-11-15

    This paper presents a control strategy of direct driven multipole PMSG wind turbines, which enhances the fault ride-through and voltage support capability of such wind turbines during grid faults. A dynamic simulation model of the turbine is implemented in the simulation software DIgSILENT. Simulation results approve the effectiveness of the developed control strategy. It is shown that PMSG wind turbines equipped with such control even enable nearby connected conventional wind turbines to ride-through grid faults. (au)

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. 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)

  4. 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)

  5. 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.

  6. 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.

  7. 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...

  8. 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....

  9. 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.

  10. 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.)

  11. Countermeasure for the magnetic drag force in guideway structure of superconducting magnetic levitation Vehicle system (MAGLEV); Chodendo jiki fujoshiki tetsudo no kozobutsu ni okeru denjiki taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, A [JR Railway Technical Research Inst., Tokyo (Japan)

    1995-02-15

    As for the levitation vehicle system, the vehicle is equipped with superconducting magnets and is levitated about 10cm by the electromagnetic force that works between the push coil and levitation guide coil laid on the ground and it runs 500km an hour. But, the running resistance and energy loss called as magnetic resistance caused by the electromagnet phenomenon that generates between the superconducting magnets and structures (steel products) generate. In this paper, the magnet resistance generated in guideway structure of superconducting magnetic levitation vehicle system and its countermeasures therefor are introduced. The main countermeasures against the magnetic resistance are as follows. The steel products have to be as arranged as separated from the superconducting magnets as far as possible in the permissible design limit. Based on the analysis results the low magnetic steel would be used in an area within 1.5m from the strand of the superconducting magnet. The contact resistance of the joints part of loop-shaped components would be bigger so as to do not cause the loop current. And the big component would be divided into small parts when it is used near to the superconducting magnets. 5 refs., 10 figs.

  12. High-efficiency and low-cost permanent magnet guideway consideration for high-T{sub c} superconducting Maglev vehicle practical application

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z; Wang, J; Zheng, J; Jing, H; Lu, Y; Ma, G; Liu, L; Liu, W; Zhang, Y; Wang, S [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: asclab@asclab.cn

    2008-11-15

    In order to improve the cost performance of the present high-T{sub c} superconducting (HTS) Maglev vehicle system for practical application, the multi-pole permanent magnet guideway (PMG) concept was introduced. A well-known double-pole Halbach PMG was chosen as a representative of multi-pole PMGs to compare with traditional monopole PMGs from the point of view of levitation efficiency and cost. Experimental results show that YBCO bulks above the double-pole Halbach PMG can exhibit better load capability and guidance performance as well as dynamics stability at the applied working height between the bulk HTSC and the PMG due to a more reasonable magnetic field distribution at the working range of bulk HTSC. Furthermore, the double-pole PMG configuration can play a more important role in improving guidance performance due to the potential-well field configuration. By comparing with former 'century' PMGs, the double-pole Halbach PMG shows another remarkable advantage in reducing the cost of levitation. As another necessary issue, magnetic field homogeneity and the corresponding magnetic drag force of a double-pole Halbach PMG has been considered by experiment in spite of the above highlights. Synthetically, the multi-pole Halbach PMG design is concluded to be one important choice for future HTS Maglev vehicle applications because of its high efficiency and low cost.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Genetic correlations between conformation traits and radiographic findings in the limbs of German Warmblood riding horses

    Directory of Open Access Journals (Sweden)

    Distl Ottmar

    2006-11-01

    Full Text Available Abstract Studbook inspection (SBI data of 20 768 German Warmblood mares and radiography results (RR data of 5102 Hanoverian Warmblood horses were used for genetic correlation analyses. The scores on a scale from 0 to 10 were given for conformation and basic quality of gaits, resulting in 14 SBI traits which were used for the correlation analyses. The radiographic findings considered included osseous fragments in fetlock (OFF and hock joints (OFH, deforming arthropathy in hock joints (DAH and distinct radiographic findings in the navicular bones (DNB which were analyzed as binary traits, and radiographic appearance of the navicular bones (RNB which was analyzed as a quasi-linear trait. Genetic parameters were estimated multivariately in linear animal models with REML using information on 24 448 horses with SBI and/or RR records. The ranges of heritability estimates were h2 = 0.14–0.34 for the RR traits and h2 = 0.09–0.50 for the SBI traits. Negative additive genetic correlations of rg = -0.19 to -0.56 were estimated between OFF and conformation of front and hind limbs and walk at hand, and between DNB and hind limb conformation. There were indications of negative additive genetic correlations between DAH and all SBI traits, but because of low prevalence and low heritability of DAH, these results require further scrutiny. Positive additive genetic correlations of rg = 0.37–0.52 were estimated between OFF and withers height and between OFH and withers height, indicating that selection for taller horses will increase disposition to develop OFF and OFH. Selection of broodmares with regards to functional conformation will assist, but cannot replace possible selection against radiographic findings in the limbs of young Warmblood riding horses, particularly with regards to OFF.

  2. 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

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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...

  8. DIOSCÓRIDES RESCATADO POR LOS ÁRABES

    Directory of Open Access Journals (Sweden)

    Ricardo H Elía

    2009-01-01

    Full Text Available La historia oficial afirma que Occidente heredó directamente el legado cultural de Grecia y Roma. Pero si la mayoría de los manuscritos griegos y latinos fueron destruidos a partir del saqueo de la Biblioteca de Alejandría en 391, los archivos de Roma fueron devastados en sendas ocasiones entre 410 y 476 por visigodos y hérulos, y los escasos vestigios clásicos que quedaban en Atenas fueron arrasados por Justiniano I en 529, ¿cuál fue la conexión que logró transmitir esa literatura y pudo ser aprovechada en un período anterior al renacimiento? La salvación de las piezas literarias se realizó durante ochocientos afios de activa y responsable tarea de recopilación por parte de los árabes durante la línea de tiempo que oscila entre 650-1450 en la que fueron rescatados, traducidos y retransmitidos hacia los cuatro puntos cardinales. Los científicos árabes, al igual que Arquímedes o Herón, nunca se separaron del saber empírico, por el contrario, lo profundizaron. El movimiento científico árabe no sólo interpretó el saber de los antiguos sino desarrolló una nueva ciencia donde la razón sustentaba a la fe y viceversa. Esta fue la base esencial que permitió construir el Renacimiento y la Ilustración, que a su vez posibilitaron la Modernidad. En este contexto, fue de capital importancia la traducción al árabe de la obra de Dioscórides ya que no sólo fue de gran utilidad para la farmacología y medicina en el mundo musulmán sino que a través de éste las recetas del médico griego de Nerón reingresaron a la Europa latina donde fueron recibidas como una panacea.Official history affirms that the West directly inherited the cultural legacy of Greece and Rome. But if most of the Greek and latin manuscripts they were destroyed at the sacking of the Library of Alexandria in 391, the archives of Rome were devastated in several occasions between 410 and 476 by Visigoth and heruls, and the little classic vestiges that were in

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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...

  20. 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.…

  1. Electromagnetic validation of fault-ride through capabilities of wind turbines

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Garcia-Valle, Rodrigo; Sharma, Ranjan

    2010-01-01

    Scope of the present project is the development and validation of electro-magnetic transient model of fixed-speed wind turbines. The research work is focused on the development of a fixed-speed wind turbine model with fault-ride through capabilities during transient over-voltages. The model is de...

  2. 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

  3. 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.

  4. 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 ...

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Quality

    International Nuclear Information System (INIS)

    Burnett, N.; Jeffries, J.; Mach, J.; Robson, M.; Pajot, D.; Harrigan, J.; Lebsack, T.; Mullen, D.; Rat, F.; Theys, P.

    1993-01-01

    What is quality? How do you achieve it? How do you keep it once you have got it. The answer for industry at large is the three-step hierarchy of quality control, quality assurance and Total quality Management. An overview is given of the history of quality movement, illustrated with examples from Schlumberger operations, as well as the oil industry's approach to quality. An introduction of the Schlumberger's quality-associated ClientLink program is presented. 15 figs., 4 ills., 16 refs

  11. 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...

  12. 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...

  13. Craftsman 42" riding lawn tractor with bagging system | News

    Science.gov (United States)

    Financial Officer Finance Section Office of the Chief Operating Officer Facilities Engineering Services Accelerator Division Accelerator Physics Center Office of the Chief Safety Officer Environment, Safety, Health and Quality Section Office of the Chief Project Officer Office of Project Support Services Office of

  14. Free-riding and team performance in project education

    NARCIS (Netherlands)

    Ruël, Gwenny Ch.; Nauta, Aukje; Bastiaans, N.

    2003-01-01

    This article derives lessons from the quality approach for further developing the organizational sustainability approach. Taking a responsibility perspective on organizational sustainability, four issues emerge that need to be resolved, i.e. what is the responsibility?, what is the responsibility

  15. Low Voltage Ride-Through Capability Solutions for Permanent Magnet Synchronous Wind Generators

    Directory of Open Access Journals (Sweden)

    Victor F. Mendes

    2016-01-01

    Full Text Available Due to the increasing number of wind power plants, several countries have modified their grid codes to include specific requirements for the connection of this technology to the power system. One of the requirements is the ride-through fault capability (RTFC, i.e., the system capability to sustain operation during voltage sags. In this sense, the present paper intends to investigate the behavior of a full-converter wind generator with a permanent magnet synchronous machine during symmetrical and asymmetrical voltage sags. Two solutions to improve the low voltage ride-through capability (LVRT of this technology are analyzed: discharging resistors (brake chopper and resonant controllers (RCs. The design and limitations of these solutions and the others proposed in the literature are discussed. Experimental results in a 34 kW test bench, which represents a scaled prototype of a real 2 MW wind conversion system, are presented.

  16. 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...

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. Electronic Power Transformer Control Strategy in Wind Energy Conversion Systems for Low Voltage Ride-through Capability Enhancement of Directly Driven Wind Turbines with Permanent Magnet Synchronous Generators (D-PMSGs

    Directory of Open Access Journals (Sweden)

    Hui Huang

    2014-11-01

    Full Text Available This paper investigates the use of an Electronic Power Transformer (EPT incorporated with an energy storage system to smooth the wind power fluctuations and enhance the low voltage ride-through (LVRT capability of directly driven wind turbines with permanent magnet synchronous generators (D-PMSGs. The decoupled control schemes of the system, including the grid side converter control scheme, generator side converter control scheme and the control scheme of the energy storage system, are presented in detail. Under normal operating conditions, the energy storage system absorbs the high frequency component of the D-PMSG output power to smooth the wind power fluctuations. Under grid fault conditions, the energy storage system absorbs the redundant power, which could not be transferred to the grid by the EPT, to help the D-PMSG to ride through low voltage conditions. This coordinated control strategy is validated by simulation studies using MATLAB/Simulink. With the proposed control strategy, the output wind power quality is improved and the D-PMSG can ride through severe grid fault conditions.

  2. 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....

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Identification and evaluation of pavement-bridge interface ride quality improvement and corrective strategies.

    Science.gov (United States)

    2011-01-01

    Bridge owners have long recognized that the approach pavement at bridges is prone to exhibiting both settlement and : cracking, which manifest as the bump at the end of the bridge. This deterioration requires considerable on-going : maintenance...

  12. Railway testing using a portable ride quality and vibration measurement system with GPS

    Science.gov (United States)

    Mee, Brian; Whitten, Brian; Neijikovsky, Boris

    1995-06-01

    To conduct the testing and evaluation of railway and railway vehicles, the Federal Railroad Administration developed a protable system that consists of accelerometers oriented in the vertical and horizontal directions, a Global Positioning System (GPS) receiver, data collection and power systems, and a portable computer. Commercial software was used to collect and display the data, while software, developed by ENSCO, was used to analyze and display results. The GPS provided dynamic location to an accuracy of 30 meters or better, and vehicle speed to within one mile per hour. The system was used in the demonstration tests of several advanced high-speed trains on Amtrak's Northeast Corrider and on other tracks in the US. The portable measurement system proved to be a simple and effective device to characterize the vibration environment of any transportation system. It is ideal for use in the assessment of the safe performance of high-speed trains operating at high cant deficiency. The system has also been used for other field tests, including braking performance and bridge monitoring. This report discusses the portable measurement system, the test applications that the system has been used for, the results of thoses tests, and the potential for improvements.

  13. Evaluation of selected effects of pavement riding quality on logistics costs in South Africa

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2011-12-01

    Full Text Available The efficient operation of a country’s economy depends, among other things, on an efficient logistical system to ensure that goods can be transported efficiently between producers and users. The costs of logistics include aspects such as transport...

  14. Ride quality evaluation. IV - Models of subjective reaction to aircraft motion

    Science.gov (United States)

    Jacobson, I. D.; Richards, L. G.

    1978-01-01

    The paper examines models of human reaction to the motions typically experienced on short-haul aircraft flights. Data are taken on the regularly scheduled flights of four commercial airlines - three airplanes and one helicopter. The data base consists of: (1) a series of motion recordings distributed over each flight, each including all six degrees of freedom of motion; temperature, pressure, and noise are also recorded; (2) ratings of perceived comfort and satisfaction from the passengers on each flight; (3) moment-by-moment comfort ratings from a test subject assigned to each airplane; and (4) overall comfort ratings for each flight from the test subjects. Regression models are obtained for prediction of rated comfort from rms values for six degrees of freedom of motion. It is shown that the model C = 2.1 + 17.1 T + 17.2 V (T = transverse acceleration, V = vertical acceleration) gives a good fit to the airplane data but is less acceptable for the helicopter data.

  15. Automated Aerial Refueling Hitches a Ride on AFF

    Science.gov (United States)

    Hansen, Jennifer L.; Murray, James E.; Bever, Glenn; Campos, Norma V.; Schkolnik, Gerard

    2007-01-01

    The recent introduction of uninhabited aerial vehicles [UAVs (basically, remotely piloted or autonomous aircraft)] has spawned new developments in autonomous operation and posed new challenges. Automated aerial refueling (AAR) is a capability that will enable UAVs to travel greater distances and loiter longer over targets. NASA Dryden Flight Research Center, in cooperation with the Defense Advanced Research Projects Agency (DARPA), the Naval Air Systems Command (NAVAIR), the Naval Air Force Pacific Fleet, and the Air Force Research Laboratory, rapidly conceived and accomplished an AAR flight research project focused on collecting a unique, high-quality database on the dynamics of the hose and drogue of an aerial refueling system. This flight-derived database would be used to validate mathematical models of the dynamics in support of design and analysis of AAR systems for future UAVs. The project involved the use of two Dryden F/A-18 airplanes and an S-3 hose-drogue refueling store on loan from the Navy. In this year-long project, which was started on October 1, 2002, 583 research maneuvers were completed during 23 flights.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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%.

  1. 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.

  2. 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.

  3. Macular hemorrhage after roller coaster riding in a single-eyed patient with congenital glaucoma

    Directory of Open Access Journals (Sweden)

    Dilek Guven

    Full Text Available ABSTRACT A 21-year-old female presented with a 4-day history of decreased vision in her only functional eye (right eye, OD. She had a history of multiple ocular surgeries in both eyes because of congenital glaucoma and had lost light perception in her left eye several years prior. Ophthalmological examination revealed 0.15 Snellen visual acuity, and fundoscopy revealed nearly total cupping and pallor of the optic disc and multiple retinal hemorrhagic foci in the macula in OD. Lesions spontaneously resolved over a few months. Gravitational forces during a roller coaster ride may have caused this macular hemorrhage.

  4. 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...

  5. 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....

  6. Improving Fault Ride-Through Capability of Variable Speed Wind Turbines in Distribution Networks

    DEFF Research Database (Denmark)

    Mokryani, Geev; Siano, P.; Piccolo, Antonio

    2013-01-01

    In this paper, a fuzzy controller for improving the fault ride-through (FRT) capability of variable speed wind turbines (WTs) equipped with a doubly fed induction generator (DFIG) is presented. DFIGs can be used as reactive power sources to control the voltage at the point of common coupling (PCC......). The controller is designed to compensate for the voltage at the PCC by simultaneously regulating the reactive and active power generated by WTs. The performance of the controller is evaluated in different case studies considering a different number of wind farms in different locations. Simulations carried out...

  7. Development of a simulation model of semi-active suspension for monorail

    Science.gov (United States)

    Hasnan, K.; Didane, D. H.; Kamarudin, M. A.; Bakhsh, Qadir; Abdulmalik, R. E.

    2016-11-01

    The new Kuala Lumpur Monorail Fleet Expansion Project (KLMFEP) uses semiactive technology in its suspension system. It is recognized that the suspension system influences the ride quality. Thus, among the way to further improve the ride quality is by fine- tuning the semi-active suspension system on the new KL Monorail. The semi-active suspension for the monorail specifically in terms of improving ride quality could be exploited further. Hence a simulation model which will act as a platform to test the design of a complete suspension system particularly to investigate the ride comfort performance is required. MSC Adams software was considered as the tool to develop the simulation platform, where all parameters and data are represented by mathematical equations; whereas the new KL Monorail being the reference model. In the simulation, the model went through step disturbance on the guideway for stability and ride comfort analysis. The model has shown positive results where the monorail is in stable condition as an outcome from stability analysis. The model also scores a Rating 1 classification in ISO 2631 Ride Comfort performance which is very comfortable as an overall outcome from ride comfort analysis. The model is also adjustable, flexibile and understandable by the engineers within the field for the purpose of further development.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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

  19. 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.

  20. 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...

  1. Riding The Waves Of Quality Improvement : Sustainability and spread in a Dutch quality improvement program for long-term care

    NARCIS (Netherlands)

    S.S. Slaghuis (Sarah)

    2016-01-01

    markdownabstractIncreasingly, sustainability and spread have become part and parcel of organizational strategy in health care. This applies in particular to organizations in the long-term care sector, which faces an increasing care demand, ageing population and labor shortage. Unfortunately,

  2. Canadian high speed magnetically levitated vehicle system

    Energy Technology Data Exchange (ETDEWEB)

    Atherton, D L [Queen' s Univ., Kingston, Ont.; Belanger, P R; Burke, P E; Dawson, G E; Eastham, A R; Hayes, W F; Ooi, B T; Silvester, P; Slemon, G R

    1978-04-01

    A technically feasible high speed (400 to 480 km/h) guided ground transportation system, based on the use of the vehicle-borne superconducting magnets for electrodynamic suspension and guidance and for linear synchronous motor propulsion was defined as a future modal option for Canadian application. Analysis and design proposals were validated by large-scale tests on a rotating wheel facility and by modelling system components and their interactions. Thirty ton vehicles carrying 100 passengers operate over a flat-topped elevated guideway, which minimizes system down-time due to ice and snow accumulation and facilitates the design of turn-outs. A clearance of up to 15 cm is produced by the electrodynamic interaction between the vehicle-borne superconducting magnets and aluminum guideway strips. Propulsion and automatic system control is provided by the superconducting linear synchronous motor which operates at good efficiency (0.74) and high power factor (0.95). The vehicle is guided primarily by the interaction between the LSM field magnet array and flat null-flux loops overlying the stator windings in the guideway. The linear synchronous motor, electrodynamic suspension as well as levitation strip joints, parasitic LSM winding losses and limitations to the use of ferromagnetic guideway reinforcement were investigated experimentally on the test wheel facility. The use of a secondary suspension assures adequate dynamic stability, and good ride quality is achieved by optimized passive components with respect to lateral modes and by an actively controlled secondary suspension with respect to vertical motion.

  3. 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…

  4. 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...

  5. 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...

  6. 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...

  7. 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

  8. 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.

  9. 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

  10. 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…

  11. 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…

  12. 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...

  13. 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

  14. 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...

  15. 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

  16. 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

  17. 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.

  18. 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...

  19. Time-domain simulation and nonlinear analysis on ride performance of four-wheel vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y S; He, H; Geng, A L [School of Automobile and Traffic Engineering, Liaoning University of Technology, Jinzhou 121001 (China)], E-mail: jzwbt@163.com

    2008-02-15

    A nonlinear dynamic model with eight DOFs of a four-wheel vehicle is established in this paper. After detaching the nonlinear characteristics of the leaf springs and shock absorbers, the multi-step linearizing method is used to simulate the vehicle vibration in time domain, under a correlated four-wheel road roughness model. Experimental verifications suggest that the newly built vehicle model and simulation procedure are reasonable and feasible to be used in vehicle vibration analysis. Furthermore, some nonlinear factors of the leaf springs and shock absorbers, which affect the vehicle ride performance (or comfort), are investigated under different vehicle running speeds. Some substaintial rules of the nonlinear vehicle vibrations are revealed in this paper.

  20. Time-domain simulation and nonlinear analysis on ride performance of four-wheel vehicles

    International Nuclear Information System (INIS)

    Wang, Y S; He, H; Geng, A L

    2008-01-01

    A nonlinear dynamic model with eight DOFs of a four-wheel vehicle is established in this paper. After detaching the nonlinear characteristics of the leaf springs and shock absorbers, the multi-step linearizing method is used to simulate the vehicle vibration in time domain, under a correlated four-wheel road roughness model. Experimental verifications suggest that the newly built vehicle model and simulation procedure are reasonable and feasible to be used in vehicle vibration analysis. Furthermore, some nonlinear factors of the leaf springs and shock absorbers, which affect the vehicle ride performance (or comfort), are investigated under different vehicle running speeds. Some substaintial rules of the nonlinear vehicle vibrations are revealed in this paper

  1. Fault Ride-Through Capability Enhancement of VSC HVDC connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

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

    2015-01-01

    This paper presents a feed forward direct current (DC) voltage control based fault ride-through (FRT) scheme for voltage source converter (VSC) high voltage DC (HVDC) connected offshore wind power plants (WPPs) in order to achieve active control of the WPP collector network AC voltage magnitude......, and to improve the FRT capability. During steady state operation, an open loop AC voltage control is implemented at the WPP side VSC of the HVDC system such that any possible control interactions between the WPP side VSC and the wind turbine VSC are minimized. Whereas during any grid faults, a dynamic AC voltage...... reference is applied based on both the DC voltage error and the AC active-current from the WPP collector system which ensures fast and robust FRT of the VSC HVDC connected offshore WPPs. Under unbalanced fault conditions in the host power system, the resulting oscillatory DC voltage is directly used...

  2. 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.

  3. 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...

  4. A review on the major sources of the interior sound vibration and riding comfort in vehicles

    Science.gov (United States)

    AlDhahebi, Adel Mohammed; Junoh, Ahmad Kadri; Ahmed, Amran

    2016-10-01

    Vehicle interior comfort is a crucial criteria that is considered by the perspective customer when purchasing a new vehicle. Meanwhile, automotive industries face the challenges for producing vehicles with better design criteria that meet the expectations of customers and eventually promote higher competitive advantages in areas of acoustic performance, cost effectiveness, product weight, and global competitive market. This review presents the major sources that influence the generation of noise and vibration in the interior part of the vehicles. It also demonstrates the relative methods that are used to assess the interior acoustics and vibration and further improve the riding comfort. This study is of a particular importance for acoustical researchers and automobile engineers, where it brings about suggestions and fundamentals that can contribute to acoustical comfort in vehicles.

  5. Modified ride-on toy cars for early power mobility: a technical report.

    Science.gov (United States)

    Huang, Hsiang-Han; Galloway, James C

    2012-01-01

    Children with significantly decreased mobility have limited opportunities to explore their physical and social environment. A variety of assistive technologies are available to increase mobility; however, no single device provides the level of functional mobility that children developing typically enjoy. The purpose of this technical report is to formally introduce a new power mobility option--the modified ride-on toy car. This report will provide (a) an overview of toy car features, (b) examples of basic electrical and mechanical modifications, and (c) a brief clinical case. With creative use and customized modifications, toy cars can function as a "general learning environment" for use in the clinic, home, and school. As such, we anticipate that these cars will become a multiuse clinical tool to address not only mobility goals but also goals involving body function and structure such as posture and movement impairments.

  6. 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.

  7. 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.

  8. Effects of hippotherapy and therapeutic horseback riding on postural control or balance in children with cerebral palsy: a meta-analysis.

    Science.gov (United States)

    Zadnikar, Monika; Kastrin, Andrej

    2011-08-01

    This research review and meta-analysis presents an overview of the effects of hippotherapy and therapeutic horseback riding (THR) on postural control or balance in children with cerebral palsy (CP). To synthesize previous research findings, a systematic review and meta-analysis were undertaken. Relevant studies were identified by systematic searches of multiple online databases from the inception of the database through to May 2010. Studies were included if they fulfilled the following criteria: (1) quantitative study design, (2) investigation of the effect of hippotherapy or THR on postural control or balance, and (3) the study group comprised children and adults with CP. The selected articles were rated for methodological quality. The treatment effect was coded as a dichotomous outcome (positive effect or no effect) and quantified by odds ratio (OR). The pooled treatment effect was calculated using a random-effects model. Meta-regression of the effect size was performed against study covariates, including study size, publication date, and methodological quality score. From 77 identified studies, 10 met the inclusion criteria. Two were excluded because they did not include a comparison group. Therapy was found to be effective in 76 out of 84 children with CP included in the intervention groups. The comparison groups comprised 89 children: 50 non-disabled and 39 with CP. A positive effect was shown in 21 of the children with CP in the comparison group regardless of the activity undertaken (i.e. physiotherapy, occupational therapy, sitting on a barrel or in an artificial saddle). The pooled effect size estimate was positive (OR 25.41, 95% CI 4.35, 148.53), demonstrating a statistically significant effectiveness of hippotherapy or THR in children with CP (phippotherapy and THR. Although the generalization of our findings may be restricted by the relatively small sample size, the results clearly demonstrate that riding therapy is indicated to improve postural control

  9. 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

  10. Sibelius: Pohjola's Daughter; Night Ride and Sunrise; Four Legends from Kalevala (Lemminkäinen Suite). Gothenburg Symphony Orchestra, Neeme Järvi / Brian Hunt

    Index Scriptorium Estoniae

    Hunt, Brian

    1997-01-01

    Uuest heliplaadist "Sibelius: Pohjola's Daughter; Night Ride and Sunrise; Four Legends from Kalevala (Lemminkäinen Suite). Gothenburg Symphony Orchestra / Neeme Järvi. Deutsche Grammophon 453 426-2; 70:37 DDD

  11. 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.

  12. 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...

  13. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  14. The Impact of Free Riding on Price and Service Competition in the Presence of E-Commerce Retailers

    OpenAIRE

    Steven Strauss

    2002-01-01

    An extensive literature has focused on price competition and the Internet; however, little attention has been given to the Internet's impact on service competition. Services include activities such as the provision of product information, repairs, faster checkout, after-sales advice/information, retail advertising, certification of products by limiting the available assortment size, and the ability to examine/test merchandise. A consumer "free rides" when the customer uses services at one ret...

  15. (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...

  16. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  17. 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.

  18. 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...

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

    OpenAIRE

    Ilona D M Bos; Rob E C M Van der Heijden; Eric J E Molin; Harry J P Timmermans

    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 evaluations of the attributes of P & R facilities, a stated choice experiment, based on the method of hierarchical information integration, was conducted in the city of Nijmegen, The Netherlands. This pape...

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Second-order sliding mode control for DFIG-based wind turbines fault ride-through capability enhancement.

    Science.gov (United States)

    Benbouzid, Mohamed; Beltran, Brice; Amirat, Yassine; Yao, Gang; Han, Jingang; Mangel, Hervé

    2014-05-01

    This paper deals with the fault ride-through capability assessment of a doubly fed induction generator-based wind turbine using a high-order sliding mode control. Indeed, it has been recently suggested that sliding mode control is a solution of choice to the fault ride-through problem. In this context, this paper proposes a second-order sliding mode as an improved solution that handle the classical sliding mode chattering problem. Indeed, the main and attractive features of high-order sliding modes are robustness against external disturbances, the grids faults in particular, and chattering-free behavior (no extra mechanical stress on the wind turbine drive train). Simulations using the NREL FAST code on a 1.5-MW wind turbine are carried out to evaluate ride-through performance of the proposed high-order sliding mode control strategy in case of grid frequency variations and unbalanced voltage sags. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  6. 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.)

  7. Diseases and parasites in wolves of the Riding Mountain National Park region, Manitoba, Canada.

    Science.gov (United States)

    Stronen, Astrid V; Sallows, Tim; Forbes, Graham J; Wagner, Brent; Paquet, Paul C

    2011-01-01

    We examined wolf (Canis lupus) blood and fecal samples from the Riding Mountain National Park (RMNP) region of Manitoba, Canada. In 601 fecal samples collected during two study periods in RMNP and the Duck Mountain Provincial Park and Forest (DMPPF) we found gastrointestinal helminth eggs from Alaria sp. (15.5%), Capillaria sp. (1.0%), taeniid tapeworms (30.8%), Toxascaris sp. (1.7%), Toxocara sp. (0.2%), Trichuris sp. (2.2%), and Moniezia sp. (0.5%). In addition, we found Demodex sp. (0.2%) and the protozoal cysts/oocysts of Sarcocystis sp. (37.3%), Cryptosporidium sp. (1.2%), coccidia (Isospora sp. or Eimeria sp.) (1.7%), and Giardia sp. (29.5%). No fecal shedding of canine parvovirus (CPV, n=387) was detected. All 18 blood samples collected in RMNP showed CPV exposure and eight of 18 blood samples indicated canine distemper virus (CDV) exposure. One wolf died from CDV. Our results are consistent with previous findings on pathogens affecting wolves and with high Giardia sp. prevalence in wolves inhabiting agricultural regions.

  8. 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.

  9. 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.

  10. 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.

  11. SciRide Finder: a citation-based paradigm in biomedical literature search.

    Science.gov (United States)

    Volanakis, Adam; Krawczyk, Konrad

    2018-04-18

    There are more than 26 million peer-reviewed biomedical research items according to Medline/PubMed. This breadth of information is indicative of the progress in biomedical sciences on one hand, but an overload for scientists performing literature searches on the other. A major portion of scientific literature search is to find statements, numbers and protocols that can be cited to build an evidence-based narrative for a new manuscript. Because science builds on prior knowledge, such information has likely been written out and cited in an older manuscript. Thus, Cited Statements, pieces of text from scientific literature supported by citing other peer-reviewed publications, carry significant amount of condensed information on prior art. Based on this principle, we propose a literature search service, SciRide Finder (finder.sciride.org), which constrains the search corpus to such Cited Statements only. We demonstrate that Cited Statements can carry different information to this found in titles/abstracts and full text, giving access to alternative literature search results than traditional search engines. We further show how presenting search results as a list of Cited Statements allows researchers to easily find information to build an evidence-based narrative for their own manuscripts.

  12. Mechanisms of Change for Children Participating in Therapeutic Horse Riding: A Grounded Theory.

    Science.gov (United States)

    Martin, R A; Graham, F P; Taylor, W J; Levack, W M M

    2017-12-13

    To develop a model for understanding mechanisms of change in health outcomes for riders with disabilities participating in therapeutic horse riding (THR). Using grounded theory methods we collected and analyzed data from interviews with 16 child riders and 18 caregivers, teachers and primary therapists, and from participant-observation during THR sessions. The central concept underpinning the model illustrating mechanisms of change was "gaining the tools to go on." Riders' experiences suggested the THR landscape (i.e., "where the tools are gathered") allowed for an expanded range of experiences in which riders could participate. Riders experienced an expansion of self-concept by learning to move, succeed, connect, and adapt (i.e., "the tools gathered") within the THR landscape. Riders then iteratively translated an expanded view of self into other environments, reflecting "how and where the tools are used." Findings suggest that positive changes in health arise from riders' experiences of learning and agency within the THR therapeutic landscape, and from the influence of these experiences on a child's developing self-concept. This article considers the wider impact of THR on children's health, beyond a focus on changes in physical outcomes.

  13. Riding Horse Harness (Based on Materials from the Chulkovo Burial Ground

    Directory of Open Access Journals (Sweden)

    Grishakov Valeriy V.

    2013-12-01

    Full Text Available The items of riding horse harness (bits with psalia, stirrups, buckles, decorations of bridles are analyzed in the article on the basis of the materials from the Chulkovo (Murom burial ground site of the 8th-10th centuries, located on right bank of the Oka river. It has been established that the use of horse harness items by the Muroma culture population, which had left the Chulkovo burial ground, is in full correspondence with the general traditions of the Finno-Ugric peoples of the Volga river region characteristic of the 8th-10th centuries. The shapes of the bits correspond to both the steppe (bits with S-shaped and straight psalia and the local traditions (bits with two and three moving rings. A tendency to uniformity is observed in the tradition of stirrups production. The main differences of the Muroma burial grounds from the neighboring Mordovian ones consist in the presence of horse burials (not known among the Mordovians, and, on the other hand, in a practically complete lack of horse harness in the funeral set of human burials. It can be assumed that the importance of cavalry with the Muromа was lower than with the Mordovians who were living next to the steppe world.

  14. 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.

  15. 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.

  16. IMPORTANT INFORMATION - Flagstaff Car-Park and Park-and-Ride (P+R)

    CERN Document Server

    GS Department

    2011-01-01

    As part of the new arrangements following the arrival of the tram-line at CERN, an Automatic Number-Plate Recognition (ANPR) system has been installed restricting access to the Flagstaff Car-park and the Park-and-Ride (P+R) zone according to the conditions set out below: Holders of a valid P+R user card may enter the car-park at all hours but may only park in the area specifically designated as the P+R zone. P+R user cards can be purchased from the Fondation des Parkings de Genève (http://www.ge.ch/parkings/abonnements.html)   Members of CERN personnel and of contractors' personnel, whatever their status, may freely access the Flagstaff Car-Park at all hours, as long as their vehicle is duly registered with CERN, but they may not use the P+R zone, which is reserved for holders of P+R user cards. Please check that your vehicle number-plates are properly registered via AdaMS (http://cern.ch/adams). If this is not the case, the following action must be taken: - for private or co...

  17. Exploring the Mode Change Behavior of Park-and-Ride Users

    Directory of Open Access Journals (Sweden)

    Shahi Taphsir Islam

    2015-01-01

    Full Text Available This paper investigates the mode change behavior of park-and-ride (P&R users, which is of considerable significance to analyze the effectiveness of P&R site on the commuters’ travel mode change as well as the increase of public transport mode share. Data from an intercept interview survey conducted at different P&R facilities in Metropolitan Melbourne is used. A questionnaire containing revealed preference (RP and stated preference (SP questions is used to interview the individuals who park at the facility and catch public transport to go to city. This study firstly aims to know the factors affecting current travel behavior using RP data and secondly to investigate the importance of the factors on influencing the commuters’ decision of travel mode choice using the SP data. The empirical models using multinomial logistic regression reveal that travel time taken by transit vehicle and transfer time at P&R stations are the primary factors affecting individuals’ decision on choosing public transport whereas parking fare is the additional factor affecting commuters’ choice of driving. Based on the results of this study, the effectiveness of P&R scheme on commuters’ travel mode change is evaluated which would be helpful to shed lights on the future construction of P&R sites.

  18. The Development of the Model for the Park and Ride System in the Major Lithuanian Cities

    Directory of Open Access Journals (Sweden)

    Vytautas Palevičius

    2014-10-01

    Full Text Available Park and Ride (P&R is the original transport system of public passengers, acting as a traditional supplement of public transport. The system is becoming widely popular in European cities. The central core of this system is composed of parking facilities in the specified parking areas at the approaches to the city with connections to public transport or special buses that allow people reach the city centre. The P&R system is based on a reduction in car density in the city centre as well as on a decrease in traffic noise, air and visual pollution. Furthermore, the P&R system is an economical and time-saving way to travel. This article has been prepared according to structural support provided by the European Union (EU for the purpose of developing the P&R system in five major Lithuanian cities – Vilnius, Kaunas, Klaipeda, Siauliai and Panevezys. Therefore, this paper is aimed at the development and application of the theoretical model of the P&R system to Lithuanian cities according to external good and bad practice.

  19. Riding the wave or paddling in the shallows? Understanding older Australians' use of the internet.

    Science.gov (United States)

    Burns, Pippa; Jones, Sandra C; Iverson, Don; Caputi, Peter

    2012-08-01

    Australia's ageing population is set to become an increasing burden on an already over-stretched primary health care system. Potential strategies to alleviate this pressure need to be investigated. Increased knowledge of older Australians' use of the internet would allow the appropriateness of online health intervention to be assessed. This initial, exploratory study examined the proportion of people aged 55 years and older who accessed the internet. It investigated their duration of use, level of comfort, use of the internet to seek health information and perceived reliability of information found on the internet. A paper based survey was distributed to a purposive sample of adults in metropolitan New South Wales. Complete data was received from 115 respondents. Sixty-two per cent of respondents reported internet use, with use decreasing with age. The majority of respondents who used the internet reported high confidence levels and long-term use. The majority had used the internet to search for health information which was generally perceived to be reliable. Logistic regression showed tertiary education and household income greater than $40,000 per year predicted use of a computer to access the internet. The majority of older Australians surveyed were successfully riding the internet wave. They have both the skills and equipment to access health information online and many were already doing so.

  20. 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

  1. 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

  2. Effect of therapeutic horseback riding on balance and gait of people with multiple sclerosis.

    Science.gov (United States)

    Muñoz-Lasa, Susana; Ferriero, Giorgio; Valero, Raquel; Gomez-Muñiz, Fernando; Rabini, Alessia; Varela, Enrique

    2011-01-01

    Exercise therapy is an important part of symptomatic and supportive treatment in patients with multiple sclerosis (PwMS). According to the literature, equine-assisted therapies--such as therapeutic horseback riding (THR) and hippotherapy (HT)--are exercise therapies that can have positive physical effects on coordination, muscle tone, postural alignment, stiffness/flexibility, endurance and strength, correcting abnormal movement patterns and improving gait and balance. While HT is known to have a positive effect on balance in PwMS, data about THR are limited. The aim of the present work was to determine the effect of THR on the balance and gait of ambulatory PwMS. Twenty-seven PwMS were included in the study. Patients were divided into two groups: 12 underwent THR and 15 traditional physiotherapy (for both groups, two series of 10 weekly sessions were performed). Before and after the study period, the following outcome measures were applied: Extended Disability Status Scale (EDSS), Barthel Index, Tinetti Performance-Oriented Mobility Assessment (POMA). In addition, patients of the THR group underwent a gait analysis to assess spatiotemporal gait parameters and ground reaction forces. The THR group showed a significant improvement in POMA scores (p<0.005) and two gait parameters: stride time (p<0.04) and ground reaction forces (p<0.01). No statistically significant change was found in the control group. The results of the study show that THR can improve balance and gait of ambulatory PwMS. Findings are preliminary, but promising and in line with the recent literature.

  3. Examination of a dual-process model predicting riding with drinking drivers.

    Science.gov (United States)

    Hultgren, Brittney A; Scaglione, Nichole M; Cleveland, Michael J; Turrisi, Rob

    2015-06-01

    Nearly 1 in 5 of the fatalities in alcohol-related crashes are passengers. Few studies have utilized theory to examine modifiable psychosocial predictors of individuals' tendencies to be a passenger in a vehicle operated by a driver who has consumed alcohol. This study used a prospective design to test a dual-process model featuring reasoned and reactive psychological influences and psychosocial constructs as predictors of riding with drinking drivers (RWDD) in a sample of individuals aged 18 to 21. College students (N = 508) completed web-based questionnaires assessing RWDD, psychosocial constructs (attitudes, expectancies, and norms), and reasoned and reactive influences (intentions and willingness) at baseline (the middle of the spring semester) and again 1 and 6 months later. Regression was used to analyze reasoned and reactive influences as proximal predictors of RWDD at the 6-month follow-up. Subsequent analyses examined the relationship between the psychosocial constructs as distal predictors of RWDD and the mediation effects of reasoned and reactive influences. Both reasoned and reactive influences predicted RWDD, while only the reactive influence had a significant unique effect. Reactive influences significantly mediated the effects of peer norms, attitudes, and drinking influences on RWDD. Nearly all effects were constant across gender except parental norms (significant for females). Findings highlight that the important precursors of RWDD were reactive influences, attitudes, and peer and parent norms. These findings suggest several intervention methods, specifically normative feedback interventions, parent-based interventions, and brief motivational interviewing, may be particularly beneficial in reducing RWDD. Copyright © 2015 by the Research Society on Alcoholism.

  4. Riding the Hype Wave: Evaluating new AI Techniques for their Applicability in Earth Science

    Science.gov (United States)

    Ramachandran, R.; Zhang, J.; Maskey, M.; Lee, T. J.

    2016-12-01

    Every few years a new technology rides the hype wave generated by the computer science community. Converts to this new technology who surface from both the science community and the informatics community promulgate that it can radically improve or even change the existing scientific process. Recent examples of new technology following in the footsteps of "big data" now include deep learning algorithms and knowledge graphs. Deep learning algorithms mimic the human brain and process information through multiple stages of transformation and representation. These algorithms are able to learn complex functions that map pixels directly to outputs without relying on human-crafted features and solve some of the complex classification problems that exist in science. Similarly, knowledge graphs aggregate information around defined topics that enable users to resolve their query without having to navigate and assemble information manually. Knowledge graphs could potentially be used in scientific research to assist in hypothesis formulation, testing, and review. The challenge for the Earth science research community is to evaluate these new technologies by asking the right questions and considering what-if scenarios. What is this new technology enabling/providing that is innovative and different? Can one justify the adoption costs with respect to the research returns? Since nothing comes for free, utilizing a new technology entails adoption costs that may outweigh the benefits. Furthermore, these technologies may require significant computing infrastructure in order to be utilized effectively. Results from two different projects will be presented along with lessons learned from testing these technologies. The first project primarily evaluates deep learning techniques for different applications of image retrieval within Earth science while the second project builds a prototype knowledge graph constructed for Hurricane science.

  5. Predictive Sea State Estimation for Automated Ride Control and Handling - PSSEARCH

    Science.gov (United States)

    Huntsberger, Terrance L.; Howard, Andrew B.; Aghazarian, Hrand; Rankin, Arturo L.

    2012-01-01

    PSSEARCH provides predictive sea state estimation, coupled with closed-loop feedback control for automated ride control. It enables a manned or unmanned watercraft to determine the 3D map and sea state conditions in its vicinity in real time. Adaptive path-planning/ replanning software and a control surface management system will then use this information to choose the best settings and heading relative to the seas for the watercraft. PSSEARCH looks ahead and anticipates potential impact of waves on the boat and is used in a tight control loop to adjust trim tabs, course, and throttle settings. The software uses sensory inputs including IMU (Inertial Measurement Unit), stereo, radar, etc. to determine the sea state and wave conditions (wave height, frequency, wave direction) in the vicinity of a rapidly moving boat. This information can then be used to plot a safe path through the oncoming waves. The main issues in determining a safe path for sea surface navigation are: (1) deriving a 3D map of the surrounding environment, (2) extracting hazards and sea state surface state from the imaging sensors/map, and (3) planning a path and control surface settings that avoid the hazards, accomplish the mission navigation goals, and mitigate crew injuries from excessive heave, pitch, and roll accelerations while taking into account the dynamics of the sea surface state. The first part is solved using a wide baseline stereo system, where 3D structure is determined from two calibrated pairs of visual imagers. Once the 3D map is derived, anything above the sea surface is classified as a potential hazard and a surface analysis gives a static snapshot of the waves. Dynamics of the wave features are obtained from a frequency analysis of motion vectors derived from the orientation of the waves during a sequence of inputs. Fusion of the dynamic wave patterns with the 3D maps and the IMU outputs is used for efficient safe path planning.

  6. 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

  7. 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.

  8. Novel scheme for enhancement of fault ride-through capability of doubly fed induction generator based wind farms

    International Nuclear Information System (INIS)

    Vinothkumar, K.; Selvan, M.P.

    2011-01-01

    Research highlights: → Proposed Fault ride-through (FRT) scheme for DFIG is aimed at energy conservation. → The input mechanical energy is stored during fault and utilized at fault clearance. → Enhanced Rotor speed stability of DFIG. → Reduced Reactive power requirement and rapid voltage recovery at fault clearance. → Improved post fault performance of DFIG at fault clearance. -- Abstract: Enhancement of fault ride-through (FRT) capability and subsequent improvement of rotor speed stability of wind farms equipped with doubly fed induction generator (DFIG) is the objective of this paper. The objective is achieved by employing a novel FRT scheme with suitable control strategy. The proposed FRT scheme, which is connected between the rotor circuit and dc link capacitor in parallel with Rotor Side Converter, consists of an uncontrolled rectifier, two sets of IGBT switches, a diode and an inductor. In this scheme, the input mechanical energy of the wind turbine during grid fault is stored and utilized at the moment of fault clearance, instead of being dissipated in the resistors of the crowbar circuit as in the existing FRT schemes. Consequently, torque balance between the electrical and mechanical quantities is achieved and hence the rotor speed deviation and electromagnetic torque fluctuations are reduced. This results in reduced reactive power requirement and rapid reestablishment of terminal voltage on fault clearance. Furthermore, the stored electromagnetic energy in the inductor is transferred into the dc link capacitor on fault clearance and hence the grid side converter is relieved from charging the dc link capacitor, which is very crucial at this moment, and this converter can be utilized to its full capacity for rapid restoration of terminal voltage and normal operation of DFIG. Extensive simulation study carried out employing PSCAD/EMTDC software vividly demonstrates the potential capabilities of the proposed scheme in enhancing the performance of

  9. Novel scheme for enhancement of fault ride-through capability of doubly fed induction generator based wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Vinothkumar, K. [Department of Electrical and Electronics Engineering, National Institute of Technology, Tiruchirappalli, Tamilnadu 620015 (India); Selvan, M.P., E-mail: selvanmp@nitt.ed [Department of Electrical and Electronics Engineering, National Institute of Technology, Tiruchirappalli, Tamilnadu 620015 (India)

    2011-07-15

    Research highlights: {yields} Proposed Fault ride-through (FRT) scheme for DFIG is aimed at energy conservation. {yields} The input mechanical energy is stored during fault and utilized at fault clearance. {yields} Enhanced Rotor speed stability of DFIG. {yields} Reduced Reactive power requirement and rapid voltage recovery at fault clearance. {yields} Improved post fault performance of DFIG at fault clearance. -- Abstract: Enhancement of fault ride-through (FRT) capability and subsequent improvement of rotor speed stability of wind farms equipped with doubly fed induction generator (DFIG) is the objective of this paper. The objective is achieved by employing a novel FRT scheme with suitable control strategy. The proposed FRT scheme, which is connected between the rotor circuit and dc link capacitor in parallel with Rotor Side Converter, consists of an uncontrolled rectifier, two sets of IGBT switches, a diode and an inductor. In this scheme, the input mechanical energy of the wind turbine during grid fault is stored and utilized at the moment of fault clearance, instead of being dissipated in the resistors of the crowbar circuit as in the existing FRT schemes. Consequently, torque balance between the electrical and mechanical quantities is achieved and hence the rotor speed deviation and electromagnetic torque fluctuations are reduced. This results in reduced reactive power requirement and rapid reestablishment of terminal voltage on fault clearance. Furthermore, the stored electromagnetic energy in the inductor is transferred into the dc link capacitor on fault clearance and hence the grid side converter is relieved from charging the dc link capacitor, which is very crucial at this moment, and this converter can be utilized to its full capacity for rapid restoration of terminal voltage and normal operation of DFIG. Extensive simulation study carried out employing PSCAD/EMTDC software vividly demonstrates the potential capabilities of the proposed scheme in

  10. 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.

  11. 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

  12. A Round for Free: How rich countries are getting a free ride on agricultural subsidies at the WTO

    OpenAIRE

    OXFAM International,

    2005-01-01

    Agricultural dumping has a devastating effect on poor countries. The Uruguay Round at the WTO was supposed to cut the subsidies that lead to dumping, but it failed to do so — as did reforms of Europe's Common Agricultural Policy and US agricultural policy. Now history is set to repeat itself: the Doha Round of negotiations is again giving rich countries a free ride to continue dumping subsidised produce on poor countries. Oxfam believes that the WTO meeting in Hong Kong must put an end to thi...

  13. Identification and evaluation of pavement-bridge interface ride quality improvement and corrective strategies : executive summary report.

    Science.gov (United States)

    2011-01-01

    Bridge owners have long recognized that the approach pavement at bridges is prone to exhibiting both : settlement and cracking, which manifest as the bump at the end of the bridge. This deterioration : requires considerable on-going maintenance...

  14. MESSENGER Educator Fellows Taking the Nation on a Ride to the Innermost Planet

    Science.gov (United States)

    Vanhala, H. A.; Goldstein, J. J.; Chapman, C. R.; Edmonds, J. P.; Hallau, K. G.; Hirshon, B.; Weir, H. M.; Solomon, S. C.

    2011-12-01

    Exploration of the mysterious planet Mercury offers an unprecedented opportunity for teachers, students, and citizens to tag along for the ride, and the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) Educator Fellows are making sure classrooms across the U.S. are treated to quite a show. The Fellows, a nationally selected team of 30 master science educator volunteers, conduct workshops to teachers on how to bring educational materials developed in support of the mission into the classroom. The goal of the program is to provide teachers and school districts with exceptional educational materials and professional development strongly tied to the space science curriculum, and the materials are designed to inspire the next generation of America's scientists and engineers through NASA missions. Since the program's inception in 2003, more than 17,000 educators have been trained by the Fellows. On the basis of data gathered from the Fellows, this figure could translate to over two million student experiences. The success of the Fellowship program can also be gauged by determining how well it has maintained its volunteer corps over the years. The Fellows, selected to the program through a national announcement of opportunity every two years, reflect a geographically and institutionally diverse mix of individuals from a variety of settings such as science centers, museums, school districts, and universities. The Fellows sign up to the program for two years at a time, and at the end of their term they have the option to reapply. To keep the number of Fellows at 30 in each cadre, new Fellows are recruited to replace those who have retired. The current, fourth cadre of Fellows includes 30 individuals in 19 states and territories. Of these, seven have been in the program since the first cadre, and the other 23 include Fellows from the second, third, and fourth recruitment campaigns in 2006, 2008, and 2010. The current cadre is conducting its work

  15. Modeling particle-facilitated solute transport using the C-Ride module of HYDRUS

    Science.gov (United States)

    Simunek, Jiri; Bradford, Scott A.

    2017-04-01

    Strongly sorbing chemicals (e.g., heavy metals, radionuclides, pharmaceuticals, and/or explosives) in soils are associated predominantly with the solid phase, which is commonly assumed to be stationary. However, recent field- and laboratory-scale observations have shown that, in the presence of mobile colloidal particles (e.g., microbes, humic substances, clays and metal oxides), the colloids could act as pollutant carriers and thus provide a rapid transport pathway for strongly sorbing contaminants. Such transport can be further accelerated since these colloidal particles may travel through interconnected larger pores where the water velocity is relatively high. Additionally, colloidal particles have a considerable adsorption capacity for other species present in water because of their large specific surface areas and their high concentrations in soil-water and groundwater. As a result, the transport of contaminants can be significantly, sometimes dramatically, enhanced when they are adsorbed to mobile colloids. To address this problem, we have developed the C-Ride module for HYDRUS-1D. This one-dimensional numerical module is based on the HYDRUS-1D software package and incorporates mechanisms associated with colloid and colloid-facilitated solute transport in variably saturated porous media. This numerical model accounts for both colloid and solute movement due to convection, diffusion, and dispersion in variably-saturated soils, as well as for solute movement facilitated by colloid transport. The colloids transport module additionally considers processes of attachment/detachment to/from the solid phase, straining, and/or size exclusion. Various blocking and depth dependent functions can be used to modify the attachment and straining coefficients. The module additionally considers the effects of changes in the water content on colloid/bacteria transport and attachment/detachment to/from solid-water and air-water interfaces. For example, when the air

  16. 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...

  17. Fault Ride Through Capability Enhancement of a Large-Scale PMSG Wind System with Bridge Type Fault Current Limiters

    Directory of Open Access Journals (Sweden)

    ALAM, M. S.

    2018-02-01

    Full Text Available In this paper, bridge type fault current limiter (BFCL is proposed as a potential solution to the fault problems of permanent magnet synchronous generator (PMSG based large-scale wind energy system. As PMSG wind system is more vulnerable to disturbances, it is essential to guarantee the stability during severe disturbances by enhancing the fault ride through capability. BFCL controller has been designed to insert resistance and inductance during the inception of system disturbances in order to limit fault current. Constant capacitor voltage has been maintained by the grid voltage source converter (GVSC controller while current extraction or injection has been achieved by machine VSC (MVSC controller. Symmetrical and unsymmetrical faults have been applied in the system to show the effectiveness of the proposed BFCL solution. PMSG wind system, BFCL and their controllers have been implemented by real time hardware in loop (RTHIL setup with real time digital simulator (RTDS and dSPACE. Another significant feature of this work is that the performance of the proposed BFCL is compared with that of series dynamic braking resistor (SDBR. Comparative RTHIL implementation results show that the proposed BFCL is very efficient in improving system fault ride through capability by limiting the fault current and outperforms SDBR.

  18. 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

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

    Directory of Open Access Journals (Sweden)

    Rui You

    2013-11-01

    Full Text Available 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 grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side 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 is proposed and a 2 MW wind turbine model is built to study the wind turbine fault ride-through capability. An integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to study its fault ride-through capability and the impact on the structural loads during grid three phase and two phase short circuit faults.

  20. 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.

  1. Evaluation of motorcyclist's discomfort during prolonged riding process with and without lumbar support

    Directory of Open Access Journals (Sweden)

    Karmegam Karuppiah

    2012-12-01

    Full Text Available OBJECTIVE: The primary aim of this study is to examine the effects of a backrest: using a prototype of a lumbar support presented in author's earlier study on the discomfort rating of the body parts of motorcyclist. METHODS: One hundred motorcyclists participated in this study, all in good physical condition and with no immediate complaint of musculoskeletal disorders. Each participant was asked to sit for 2 hours on a motorcycle in two different sessions (with and without the lumbar support in a controlled room environment. At every 15 minutes interval the participants were required to rate their discomfort level on the Borg's CR-10 questionnaire. RESULTS: The rate of discomfort level (in all body parts decreased over time during the testing period with the prototype. In terms of the discomfort 'break point', participants identified low back and upper back as the most affected body parts prior to comfort changes during the testing period with the use of the prototype. CONCLUSIONS: The use of this prototype provides a protective mechanism for the motorcyclist's musculoskeletal system, particularly the spinal column. Therefore, this prototype is capable of providing ideal posture while simultaneously enhancing the comfortability of the motorcyclist during the riding process (by reducing discomfort.OBJETIVO: O objetivo principal deste estudo é analisar os efeitos de um encosto, usando um protótipo de um apoio lombar apresentado em estudo anterior do autor sobre a avaliação de desconforto das partes do corpo do motociclista. MÉTODOS: Cem motociclistas participaram neste estudo, todos em boas condições físicas e sem queixa imediata de lesões músculo-esqueléticas. Cada participante foi convidado a se sentar por 2 horas em uma moto em duas sessões diferentes (com e sem o apoio lombar em uma sala com ambiente controlado. A cada intervalo de 15 minutos, os participantes foram solicitados a classificar o seu nível de desconforto no question

  2. Owning the Journey: Using Collaborative Revisions of Little Red Riding Hood in Teaching Introduction to Literature at a Historically Black University

    Science.gov (United States)

    Scott, Pauline

    2012-01-01

    Design and implementation of a collaborative course project, using Little Red Riding Hood (LRRH) to teach and discuss the concepts of orality, cultural legacy, archetypes, adaptation/appropriation, and social criticism in an Introduction to Literature course at Historically Black Alabama State University in Montgomery, Alabama. The student groups…

  3. 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.

  4. Humanism, Modernism and Designing Education: Exploring Progressive Relations between Australia, New Zealand and the West Riding of Yorkshire 1930s-1970s

    Science.gov (United States)

    Burke, Catherine

    2018-01-01

    This article takes as a starting point the career of Sir Alec Clegg, Chief Education Officer for the West Riding of Yorkshire (1945-1974), and traces his professional connections with educationists in Australia and New Zealand. In exploring the nature of global exchanges between educators, artists, architects and designers in the decades…

  5. Coordination between Fault-Ride-Through Capability and Over-current Protection of DFIG Generators for Wind Farms

    DEFF Research Database (Denmark)

    Bak-Jensen, Birgitte; Kawady, T.A.; Abdel-Rahman, Mansour Hassan

    2010-01-01

    is investigated. Simulation test cases using MATLAB-Simulink are implemented on a 365-MW wind farm in AL-Zaafarana, Egypt. The simulation results show the influence of the FRT capability on the protective relaying coordination in wind farms, showing that the FRT may work in situations where is were expected......Fault Ride-Through (FRT) capabilities set up according to the grid codes may affect the performance of related protective elements during fault periods. Therefore, in this paper the coordination between the FRT capability and over-current protection of DFIG Wind Generators in MV networks...... not to work, and then disabling the over-current protection, which should have worked in this situation....

  6. 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....

  7. 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.

  8. 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.

  9. 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.

  10. 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....

  11. 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.)

  12. 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.

  13. 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.

  14. 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.

  15. Local search heuristics for the probabilistic dial-a-ride problem

    DEFF Research Database (Denmark)

    Ho, Sin C.; Haugland, Dag

    2011-01-01

    evaluation procedure in a pure local search heuristic and in a tabu search heuristic. The quality of the solutions obtained by the two heuristics have been compared experimentally. Computational results confirm that our neighborhood evaluation technique is much faster than the straightforward one...

  16. Development of metacognitive skills in young adolescents : a bumpy ride to the high road

    NARCIS (Netherlands)

    Stel, Manita van der

    2011-01-01

    This thesis shows the final results of a longitudinal project where the same participants (12 to 15 yrs.) were followed for three consecutive years. The first objective of this study was to investigate the development of both quantity and quality of metacognitive skills. The second objective was to

  17. 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

  18. 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 ...

  19. Lechery, lycanthropy and Little Red Riding Hood in Type O Negative’s ‘Wolf Moon (Including Zoanthropic Paranoia)’

    OpenAIRE

    Digioia, A.

    2016-01-01

    Type O Negative’s ‘Wolf Moon (including Zoanthropic Paranoia)’ seems to be a melodic ode to lascivious werewolves or to sexual intercourse during menstruation, which is transformative, allowing participation to channel animalistic instincts. Subject to more critical examination, ‘Wolf Moon (including Zoanthropic Paranoia)’ can also be presented as a contemporary incarnation of the ‘Little Red Riding Hood’ myth. Both contain the same themes: the stigmatization of eroticism, reclamation of agen...

  20. Therapeutic Horseback Riding Crossover Effects of Attachment Behaviors with Family Pets in a Sample of Children with Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Jessie D. Petty

    2017-03-01

    Full Text Available The unique needs of individuals with autism spectrum disorder (ASD have implications for animal welfare. This nested pilot study examined the effects of a randomized trial of 10-week therapeutic horseback riding (THR intervention versus a no-horse barn activity (BA control group on children’s behaviors with family pets. Sixty-seven (THR n = 31; BA n = 36 participants with ASD (ages 6–16 years with one or more family pet, were enrolled from a larger trial (n = 116 following their randomization to intervention groups, stratified by nonverbal intellectual ability. A consistent caregiver completed questionnaires about participants’ interactions with their household pets pre- and post-intervention. Caregivers of THR group participants reported significant improvements in participants’ caring actions with the family pet compared with the BA group (p = 0.013; effect size = 0.74. Engaging with horses during a standard THR intervention protocol may generalize to improving caring actions toward family pets in children and adolescents with ASD.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Fire Regime in Marginal Jack Pine Populations at Their Southern Limit of Distribution, Riding Mountain National Park, Central Canada

    Directory of Open Access Journals (Sweden)

    Jacques C. Tardif

    2016-09-01

    Full Text Available In central Canada, long fire history reconstructions are rare. In a context where both anthropogenic and climate influences on fire regime have changed, Parks Canada has a mandate to maintain ecological integrity. Here we present a fire history derived from fire-scarred jack pine (Pinus banksiana Lamb. trees growing at their southern distribution limit in Riding Mountain National Park (RMNP. In Lake Katherine Fire Management Unit (LKFMU, a subregion within the park, fire history was reconstructed from archival records, tree-ring records, and charcoal in lake sediment. From about 1450 to 1850 common era (CE the fire return intervals varied from 37 to 125 years, according to models. During the period 1864–1930 the study area burned frequently (Weibull Mean Fire Intervals between 2.66 and 5.62 years; this period coincided with the end of First Nations occupation and the start of European settlement. Major recruitment pulses were associated with the stand-replacing 1864 and 1894 fires. This period nevertheless corresponded to a reduction in charcoal accumulation. The current fire-free period in LKFMU (1930–today coincides with RMNP establishment, exclusion of First Nations land use and increased fire suppression. Charcoal accumulation further decreased during this period. In the absence of fire, jack pine exclusion in LKFMU is foreseeable and the use of prescribed burning is advocated to conserve this protected jack pine ecosystem, at the southern margins of its range, and in the face of potential climate change.

  8. 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.

  9. The role of sensation seeking, perceived peer pressure, and harmful alcohol use in riding with an alcohol-impaired driver.

    Science.gov (United States)

    Kim, Jun-Hong; Kim, Kwang Sik

    2012-09-01

    Alcohol-related motor vehicle collisions have been the top of policy agenda for more than three decades in Korea. Despite implementation of various traffic safety measures, some drivers' alcohol use and abuse has resulted in a high number of alcohol-impaired traffic fatalities every year. This paper presents the association of theoretical factors with behavior of riding with an alcohol-impaired driver (RAID) among all age groups in the Korean adult sample. The theoretical factors of the drivers are personality factor, socio-psychological factor, and alcohol-related behavioral risk factor. We utilized national survey data from 1007 respondents consisting of 703 males and 304 females aged 20-66 collected by Korean Institute of Criminology (KIC) to test our theorized model. Our results indicated that there were three major predictors of RAID involvement: sensation seeking propensity, perceived peer pressure, and frequent harmful drinking. Overall, prediction of RAID behavior by gender was mediated entirely through these predictors. The issue of males' higher risk of RAID involvements was addressed for effective communication strategies such as campaigns. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Riding the dragon: enhancing resilient leadership and sensible self-care in the healthcare executive.

    Science.gov (United States)

    Wicks, Robert J; Buck, Tina C

    2013-01-01

    With challenges in the healthcare system growing, strengthened leader and organizational resilience is often overlooked as a factor that can support staff morale and sustain performance improvement and quality. Here we examine resilience-building practices related to self-awareness, alone time, mindfulness, and a healthy perspective. A key aspect of management resilience is weighing the costs and benefits to the executive personally and to the organization if the warning signals of impairment are left untended. To that end, we propose a leader self-care protocol, which even the busy healthcare executive can find time to undertake. Ifimplemented, the protocol will allow leaders to lessen their vulnerability to burnout and help teammates whose resilience may be stretched thin. Finally, we present healthy coping skills for daily stressors and for the sudden and overwhelming situations that can negatively affect resilience.

  11. Riding the Plane Wave: Considerations for In Vivo Study Designs Employing High Frame Rate Ultrasound

    Directory of Open Access Journals (Sweden)

    Jason S. Au

    2018-02-01

    Full Text Available Advancements in diagnostic ultrasound have allowed for a rapid expansion of the quantity and quality of non-invasive information that clinical researchers can acquire from cardiovascular physiology. The recent emergence of high frame rate ultrasound (HiFRUS is the next step in the quantification of complex blood flow behavior, offering angle-independent, high temporal resolution data in normal physiology and clinical cases. While there are various HiFRUS methods that have been tested and validated in simulations and in complex flow phantoms, there is a need to expand the field into more rigorous in vivo testing for clinical relevance. In this tutorial, we briefly outline the major advances in HiFRUS, and discuss practical considerations of participant preparation, experimental design, and human measurement, while also providing an example of how these frameworks can be immediately applied to in vivo research questions. The considerations put forward in this paper aim to set a realistic framework for research labs which use HiFRUS to commence the collection of human data for basic science, as well as for preliminary clinical research questions.

  12. Comparing hiking, mountain biking and horse riding impacts on vegetation and soils in Australia and the United States of America.

    Science.gov (United States)

    Pickering, Catherine Marina; Hill, Wendy; Newsome, David; Leung, Yu-Fai

    2010-01-01

    Hiking, horse riding and mountain biking are popular in protected areas in Australia and the United States of America. To help inform the often contentious deliberations about use of protected areas for these three types of activities, we review recreation ecology research in both countries. Many impacts on vegetation, soils and trails are similar for the three activities, although there can be differences in severity. Impacts include damage to existing trails, soil erosion, compaction and nutrification, changes in hydrology, trail widening, exposure of roots, rocks and bedrock. There can be damage to plants including reduction in vegetation height and biomass, changes in species composition, creation of informal trails and the spread of weeds and plant pathogens. Due to differences in evolutionary history, impacts on soil and vegetation can be greater in Australia than in the USA. There are specific social and biophysical impacts of horses such as those associated with manure and urine, grazing and the construction and use of tethering yards and fences. Mountain bike specific impacts include soil and vegetation damage from skidding and the construction of unauthorised trails, jumps, bridges and other trail technical features. There are gaps in the current research that should be filled by additional research: (1) on horse and mountain bike impacts to complement those on hiking. The methods used need to reflect patterns of actual usage and be suitable for robust statistical analysis; (2) that directly compares types and severity of impacts among activities; and (3) on the potential for each activity to contribute to the spread of weeds and plant pathogens. Additional research will assist managers and users of protected areas in understanding the relative impacts of these activities, and better ways to manage them. It may not quell the debates among users, managers and conservationists, but it will help put it on a more scientific footing. 2009 Elsevier Ltd. All

  13. BIOMECHANICS OF THERAPEUTIC RIDING DURING THE DISEASES OF I-II DEGREE DYSPLASTIC LUMBAR AND STATIC (SHORT LEG) SCOLIOSIS.

    Science.gov (United States)

    Sheshaberidze, E; Merabishvili, I; Loria, M

    2015-11-01

    The goal of the paper is to substantiate the essence of ridetherapy biomechanics as the pathogenetic therapeutic and prophylactic method at lumbar dysplastic (the I and II degrees) and static (short-legged induced) scoliosis. Uneven lower extremities caused by any reason and asymmetric support induce the change in the arrangement of trochantin to the vertebra and correspondingly the uneven loading of lumbar muscles. The asymmetric strength of lumbar muscles evoked by the change in rotator condition becomes the cause of the formation of scoliosis primary arc which, in its turn, causes a compensatory spinal curvature. In case of dysplastic scoliosis a leading role belongs to the beginning of dystrophic changes in intervertebral discs and its further decentration. At riding position the lower extremities are completely disengaged from the antigravity redistribution, the child is in direct contact with vibrations and jolts coming from the horseback; the antigravity loading is distributed on the muscles of the torso and thus, it creates an opportunity to purposefully affect the correction of the spine. During scoliosis the pathogenic essence of ridetherapy is due to the comprehensiveness of its procedures, expressed in the fact that during one procedure several factors are influenced simultaneously: nucleus pulpous, the torso and iliopsoas muscles, the antigravity system, etc. According to the clinical-functional and radiographic studies carried out in the dynamics on 11-16 years old adolescents it has been established that in those groups where the rehabilitation was conducted in a complex with ridetherapy the authentically higher results were obtained as compared to the groups where the rehabilitation was held using therapeutic exercises and massage.

  14. Sustainable people development - How to ride the Waves of Critical Professions?

    International Nuclear Information System (INIS)

    Unkrig, E. R.

    2011-01-01

    In order to ensure sustainable business development and sustainable business success, enterprises must know what know-how and what capabilities are required to achieve this. In this context AREVA ask themselves what positions or functions must be considered 'critical' in this connection. Due to this, a common definition was developed on a European level as a first step for what is understood by AREVA as being 'critical': Strategically important occupational fields in which AREVA must ensure sustainable knowledge and experience; Occupational images which are difficult to recruit on the labour market; Occupational images which are difficult to be qualified internally; Occupational fields with a significant quantitative development; Occupational fields which are facing a significant (further) development of skills. On behalf of the senior management the German project 'Critical Job Observatory' was implemented in the year 2010. In order to ensure the consistent use of the definitions, 'face to face interviews' were implemented. These talks were conducted exclusively by People Development Germany - with the help of Technical Support to ensure the data quality by validating the technical statements about criticality. To achieve the commitment on all management levels, the interviews were conducted top-down. In the first interview rounds the critical jobs were identified with the BU Heads of the Business Units New Builds, Installed Base, Products and Technology and Fuel, with the Division Heads from E and P and the Direct Reports to the Executive Management in the corporate sector within their respective business areas using the aforementioned criteria. In addition the criticality of the critical jobs was determined with three questions: Influence on the business success; Probability of job vacancy in relation to the succession situation; Number of know-how carriers in the GmbH including subsidiaries. To obtain more detailed information about the identified critical job

  15. Re-examination of Chinese semantic processing and syntactic processing: evidence from conventional ERPs and reconstructed ERPs by residue iteration decomposition (RIDE.

    Directory of Open Access Journals (Sweden)

    Fang Wang

    Full Text Available A number of studies have explored the time course of Chinese semantic and syntactic processing. However, whether syntactic processing occurs earlier than semantics during Chinese sentence reading is still under debate. To further explore this issue, an event-related potentials (ERPs experiment was conducted on 21 native Chinese speakers who read individually-presented Chinese simple sentences (NP1+VP+NP2 word-by-word for comprehension and made semantic plausibility judgments. The transitivity of the verbs was manipulated to form three types of stimuli: congruent sentences (CON, sentences with a semantically violated NP2 following a transitive verb (semantic violation, SEM, and sentences with a semantically violated NP2 following an intransitive verb (combined semantic and syntactic violation, SEM+SYN. The ERPs evoked from the target NP2 were analyzed by using the Residue Iteration Decomposition (RIDE method to reconstruct the ERP waveform blurred by trial-to-trial variability, as well as by using the conventional ERP method based on stimulus-locked averaging. The conventional ERP analysis showed that, compared with the critical words in CON, those in SEM and SEM+SYN elicited an N400-P600 biphasic pattern. The N400 effects in both violation conditions were of similar size and distribution, but the P600 in SEM+SYN was bigger than that in SEM. Compared with the conventional ERP analysis, RIDE analysis revealed a larger N400 effect and an earlier P600 effect (in the time window of 500-800 ms instead of 570-810ms. Overall, the combination of conventional ERP analysis and the RIDE method for compensating for trial-to-trial variability confirmed the non-significant difference between SEM and SEM+SYN in the earlier N400 time window. Converging with previous findings on other Chinese structures, the current study provides further precise evidence that syntactic processing in Chinese does not occur earlier than semantic processing.

  16. 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.

  17. 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...

  18. 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...

  19. Playground slide-related injuries in preschool children: increased risk of lower extremity injuries when riding on laps.

    Science.gov (United States)

    Jennissen, Charles A; Koos, Maggie; Denning, Gerene

    2018-04-10

    The purpose of this study was to better understand the factors associated with playground slide-related injuries in preschool children and to test the hypothesis that riding on laps increases the likelihood of lower extremity injuries. Playground slide-related injuries (product code 1242) in children ≤5 years of age treated in emergency departments from 2002 to 2015 were identified (N = 12,686) using the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS). Descriptive and comparative analyses, including chi-square testing and binary logistic regression, were performed. Based on NEISS stratified national sampling estimates, over 350,000 children ≤5 years of age were injured on slides from 2002 to 2015. Overall, 59% of the children were male, and 65% were white. Almost 60% of injuries occurred in parks or other public areas. The most frequent diagnosis was a fracture (36%); lacerations were 19% of the injuries. A higher proportion of musculoskeletal injuries were seen in toddlers < 3 years old as compared to those 3-5 years of age (p < 0.001). Injuries to the lower extremities increased in frequency as age decreased, whereas injuries to the upper extremities and head/neck/face were more common in older preschoolers. Children < 3 years of age were 12 times more likely to be identified from narratives as being on another person's lap at the time of injury. Children identified as being on a lap had an increased odds of injury to the lower extremity than to other body parts (OR 43.0, 95% confidence interval (CI) 32.0-58.0), and of lower leg/ankle fracture than fractures elsewhere (OR 49.5, 95% CI 31.7-77.4). Decreasing age was associated with a higher likelihood of being identified as sliding down on another person's lap and a higher likelihood of lower extremity injuries. Healthcare providers should be mindful of the potential for these slide-related injuries as they can result in a toddler's fracture of

  20. 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...

  1. Along for the ride

    DEFF Research Database (Denmark)

    Buchmann, Kurt

    2008-01-01

    Problemer associeret med Gyrodactylus salaris og dens introduktion i laksebestande med høj følsomhed kan true bestanden......Problemer associeret med Gyrodactylus salaris og dens introduktion i laksebestande med høj følsomhed kan true bestanden...

  2. Riding the cycle

    Energy Technology Data Exchange (ETDEWEB)

    Webster, G. [Canadian Association of Petroleum Producers, Calgary, AB (Canada)

    2001-07-01

    The current state of the Canadian oil and natural gas industry is reviewed as part of a discussion of economic cycles focusing in particular on the most recent cycle and the impact it has had on the industry. The review of the state of the industry includes discussion of production, exports, commodity prices, the stimulating effect of price increases on the number of oil and natural gas wells drilled, drilling rig operating days. Also discussed are the effect of foreign exchange rates, capital spending, industry financial performance in terms of return on capital employed, the impact of oil and gas prices on Alberta provincial revenues, estimates of Canada's ultimate crude oil and natural gas resources potential, pipelines and pipeline proposals for northern gas, and projection of crude oil and natural gas production in Canada to 2010.

  3. Riding the Asian Wave....

    Science.gov (United States)

    Ward, Ben

    1999-01-01

    Discusses strategies U.S. universities are using to deal with declining enrollments by Asian students, brought on by the Asian financial crisis. Strategies include recruiting students from other countries. (Author/VWL)

  4. Riding with the ants

    NARCIS (Netherlands)

    Duarte, A. P. M.; Attili-Angelis, D.; Baron, N. C.; Groenewald, Johannes Z.; Crous, Pedro W.; Pagnocca, F. C.

    Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains studied revealed that they cluster in two main lineages. The first was associated with the genus

  5. Riding a tiger

    International Nuclear Information System (INIS)

    Cube, A. von.

    1977-01-01

    Nuclear energy, which has become somewhat shady by now, seems to be the evil demon of this age to many people. Therfore the author is striving for comprehensive information on nuclear energy, its technical aspects, its safety risks and its social accompaniments. With the help of this comprehensible and well-grounded basic knowledge on this complex of problems the reader might be able to make up his own mind. Nuclear energy remains a challenge to mankind by which it may fail but does not necessarily have to fail if it is aware of the social requirements of the Atomic age. (GL) [de

  6. Riding the Technology Wave.

    Science.gov (United States)

    Malan, Pierre

    This paper presents an overview of information technology development. The first section sets the scene, comparing the first WAN (Wide Area Network) and Intel processor to current technology. The birth of the microcomputer is described in the second section, including historical background on semiconductors, microprocessors, and the microcomputer.…

  7. Riding the belt

    Energy Technology Data Exchange (ETDEWEB)

    Potts, A

    1998-04-01

    Recent developments in conveyor systems have focused on accessories rather than the belt itself. Radio frequency identification (RFID) is a technology using transponders embedded in conveyor belts and this is the latest development at the German firm Contitech. The system described in the articles developed with Moers, features transponders for cooling, controlling and monitoring conveyor belts. Other developments mentioned include a JOKI drum motor featuring a fully integrated gearbox and electric motor enclosed in a steel shell, from Interoll; a new scraper cleaning system from Hosch, new steel cord belting from Fenner, a conveying system for Schleenhain lignite opencast mine by FAM Foerdelantigen Magdeburg; new bearings from Nadella (the sales arm of Intersoll-Rand), an anti-shock belt transfer table from Rosta and new caliper disc brakes from GE Industrial.

  8. Riding the Nexus

    DEFF Research Database (Denmark)

    Mitchell, Dr. William L.

    cases. The first case deals with efforts to move from education to training through the teaching of Target Network Modeling as a common language and technique for the production of intelligence products to facilitate shared situational awareness. The second case, examines efforts to move from training...

  9. Riding the ocean waves

    International Nuclear Information System (INIS)

    Yemm, Richard

    2000-01-01

    It is claimed that important developments over the past five years mean that there will be a range of competing pre-commercial wave-energy systems by 2002. The generation costs should be on a par with biomass schemes and offshore wind systems. The environmental advantages of wave energy are extolled. Ocean Power Delivery (OPD) have produced a set of criteria to be satisfied for a successful wave power scheme and these are listed. OPD is responsible for the snake-like Pelamis device which is a semi-submerged articulated series of cylindrical sections connected through hinged joints. How the wave-induced movement of the hinges is used to generate electricity is explained. The system is easily installed and can be completely removed at the end of its life

  10. Riding the MOOC Tsunami

    Science.gov (United States)

    Bauer, Wolfgang

    2014-03-01

    Massive Open Online Courses (MOOCs) have the potential to revolutionize teaching and learning at universities. It is even conceivable that MOOCs can endanger the basic business model of higher education, because they have the potential to erase traditional brick-and-mortar advantages. I will discuss our experiences with 15 years of offering online physics courses at Michigan State University, and lessons learned in doing so.

  11. Riding the RAFT

    Science.gov (United States)

    Gunter, Melissa D.

    2016-01-01

    Writing about mathematics holds a wealth of benefits for students. When students are given opportunities to write in math class, it helps develop mathematical thinking and language, encourages self-reflection, and provides a better way to organize ideas. Many teachers incorporate journaling and other types of reflective writing into their…

  12. Riding the cycle

    International Nuclear Information System (INIS)

    Webster, G.

    2001-01-01

    The current state of the Canadian oil and natural gas industry is reviewed as part of a discussion of economic cycles focusing in particular on the most recent cycle and the impact it has had on the industry. The review of the state of the industry includes discussion of production, exports, commodity prices, the stimulating effect of price increases on the number of oil and natural gas wells drilled, drilling rig operating days. Also discussed are the effect of foreign exchange rates, capital spending, industry financial performance in terms of return on capital employed, the impact of oil and gas prices on Alberta provincial revenues, estimates of Canada's ultimate crude oil and natural gas resources potential, pipelines and pipeline proposals for northern gas, and projection of crude oil and natural gas production in Canada to 2010

  13. Ride Motion Simulator (RMS)

    Data.gov (United States)

    Federal Laboratory Consortium — The RMS is a simulator designed for crew station and man-in-the-loop experimentation. The simulator immerses users in a synthetic battlefield to experience realistic...

  14. Ride the wave

    DEFF Research Database (Denmark)

    Sørensen, Jakob B

    2017-01-01

    The functions of four of the five proteins in the mammalian uncoordinated-13 (Munc13) family have been identified as priming factors in SNARE-dependent exocytosis. In this issue, Zhang et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201702099) show that the fifth member, BAIAP3 (brain...

  15. Renewable Energy Riding High

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    China is putting greater emphasis on green energy as it tries to clean up industry and meet target for cuts in carbon emissions over the past two years, China has already leapfrogged competitors from Denmark, Germany, Spain and the United States to become the world's largest maker of wind turbines and solar panels. At the same time, the country is also taking steps to build more nuclear reactors and energy-efficient coal power plants.

  16. 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

  17. Magnetic resonance imaging findings of the lumbar spine in elite horseback riders: correlations with back pain, body mass index, trunk/leg-length coefficient, and riding discipline.

    Science.gov (United States)

    Kraft, Clayton N; Pennekamp, Peter H; Becker, Ute; Young, Mei; Diedrich, Oliver; Lüring, Christian; von Falkenhausen, Makus

    2009-11-01

    Most orthopaedic problems experienced by competitive horseback riders are related to pain in the lower back, hip joint, and hamstring muscles. Riders-especially, show jumpers-are frequently hampered in their performance because of lumbar pain. To date, there has been no research into lumbar disk degeneration in elite competitive riders. Competitive horseback riding accelerates lumbar disk degeneration. Cross-sectional study; Level of evidence, 3. Fifty-eight elite riders (18 men, 40 women; mean age, 32.4 years) and a control group of 30 nonriding volunteers (17 men, 13 women; mean age, 28.7 years) were evaluated for lumbar disk degeneration, cross-sectional area of paraspinal muscles, spondylolysis, and spondylolisthesis, using magnetic resonance imaging (MRI). The prevalence of disk degeneration between the 2 groups was compared, and the relationship was investigated between low back pain (LBP), riding discipline, body mass index (BMI), trunk/leg-length coefficient, and MRI results. Eighty-eight percent of elite riders (n = 51) had a history of LBP, versus 33% of the controls (P back pain. Although riders have a high prevalence of LBP, there is no conclusive MRI evidence to suggest that the cause lies in undue disk degeneration, spondylolysis, spondylolisthesis, or pathologic changes of the paraspinal muscles of the lumbar spine.

  18. Dynamic Response of a Long-Span Concrete-Filled Steel Tube Tied Arch Bridge and the Riding Comfort of Monorail Trains

    Directory of Open Access Journals (Sweden)

    Hongye Gou

    2018-04-01

    Full Text Available In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train–bridge system is established to investigate the dynamic behaviors of the bridge under moving trains. A refined three-dimensional finite element model is built for the bridge and a 15 degrees-of-freedom vehicle model is presented for the train. The numerical model is validated using in-situ test results and then used to analyze the dynamic displacement and acceleration of the bridge and the trains on the bridge. Based on the simulation results, the impact factor of the bridge is investigated and the riding comfort of the trains is evaluated. The investigation results show that the impact factor of vehicle loads reaches the maximum value when the resonance of the bridge is induced by the moving vehicles. The effect of train braking predominates the longitudinal vibration of the bridge but is negligible in the transverse and vertical directions. The vehicle speed is the dominating factor for the riding comfort of the train.

  19. Study on the energy-efficiency of 'park and ride' systems (French/German version); Efficience energetique des P et R

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume-Gentil, S.; Camandona, Ch.; Stucki, M. [Transitec Ingenieurs Conseils, Lausanne (Switzerland); Baumgartner, P.; Lippuner, Ch. [Ernst Basler und Partner AG, Zuerich (Switzerland)

    2004-07-01

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines the efficiency of 'park and ride' (P+R) systems from the energy-efficiency point of view. 'Park and ride' means: 'Leave your car on a parking area and travel by public transport services for the second part of your journey'. Five hypotheses are examined: that P+R helps improve the general energy-efficiency of traffic, P+R installations are not an economically advantageous measure for improving the energy-efficiency of traffic, that they are not cost-effective, that they are financed by other public transport services and that their contribution to energy efficiency is dependent on the characteristics of their particular locations. The study looks at the positive and negative effects of P+R on energy efficiency and develops criteria for choosing locations. Three typical P+R installations are looked at - at a main station in a city centre, on the edge of a city and on a main city access road. These locations are analysed with respect to their energy and financial balances and their cost-effectiveness. Also, the use of P+R installations is analysed and the importance of the results of the study for traffic planning is discussed.

  20. Study on the energy-efficiency of 'park and ride' systems (French version); Efficience energetique des P et R

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume-Gentil, S.; Camandona, Ch.; Stucki, M. [Transitec Ingenieurs Conseils, Lausanne (Switzerland); Baumgartner, P.; Lippuner, Ch. [Ernst Basler und Partner AG, Zuerich (Switzerland)

    2004-07-01

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines the efficiency of 'park and ride' (P+R) systems from the energy-efficiency point of view. 'Park and ride' means: 'Leave your car on a parking area and travel by public transport services for the second part of your journey'. Five hypotheses are examined: that P+R helps improve the general energy-efficiency of traffic, P+R installations are not an economically advantageous measure for improving the energy-efficiency of traffic, that they are not cost-effective, that they are financed by other public transport services and that their contribution to energy efficiency is dependent on the characteristics of their particular locations. The study looks at the positive and negative effects of P+R on energy efficiency and develops criteria for choosing locations. Three typical P+R installations are looked at - at a main station in a city centre, on the edge of a city and on a main city access road. These locations are analysed with respect to their energy and financial balances and their cost-effectiveness. Also, the use of P+R installations is analysed and the importance of the results of the study for traffic planning is discussed.

  1. 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

  2. Fault tolerant computer control for a Maglev transportation system

    Science.gov (United States)

    Lala, Jaynarayan H.; Nagle, Gail A.; Anagnostopoulos, George

    1994-01-01

    Magnetically levitated (Maglev) vehicles operating on dedicated guideways at speeds of 500 km/hr are an emerging transportation alternative to short-haul air and high-speed rail. They have the potential to offer a service significantly more dependable than air and with less operating cost than both air and high-speed rail. Maglev transportation derives these benefits by using magnetic forces to suspend a vehicle 8 to 200 mm above the guideway. Magnetic forces are also used for propulsion and guidance. The combination of high speed, short headways, stringent ride quality requirements, and a distributed offboard propulsion system necessitates high levels of automation for the Maglev control and operation. Very high levels of safety and availability will be required for the Maglev control system. This paper describes the mission scenario, functional requirements, and dependability and performance requirements of the Maglev command, control, and communications system. A distributed hierarchical architecture consisting of vehicle on-board computers, wayside zone computers, a central computer facility, and communication links between these entities was synthesized to meet the functional and dependability requirements on the maglev. Two variations of the basic architecture are described: the Smart Vehicle Architecture (SVA) and the Zone Control Architecture (ZCA). Preliminary dependability modeling results are also presented.

  3. 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...

  4. 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.

  5. 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.

  6. Fault Ride-through Capability Enhancement of Voltage Source Converter-High Voltage Direct Current Systems with Bridge Type Fault Current Limiters

    Directory of Open Access Journals (Sweden)

    Md Shafiul Alam

    2017-11-01

    Full Text Available This paper proposes the use of bridge type fault current limiters (BFCLs as a potential solution to reduce the impact of fault disturbance on voltage source converter-based high voltage DC (VSC-HVDC systems. Since VSC-HVDC systems are vulnerable to faults, it is essential to enhance the fault ride-through (FRT capability with auxiliary control devices like BFCLs. BFCL controllers have been developed to limit the fault current during the inception of system disturbances. Real and reactive power controllers for the VSC-HVDC have been developed based on current control mode. DC link voltage control has been achieved by a feedback mechanism such that net power exchange with DC link capacitor is zero. A grid-connected VSC-HVDC system and a wind farm integrated VSC-HVDC system along with the proposed BFCL and associated controllers have been implemented in a real time digital simulator (RTDS. Symmetrical three phase as well as different types of unsymmetrical faults have been applied in the systems in order to show the effectiveness of the proposed BFCL solution. DC link voltage fluctuation, machine speed and active power oscillation have been greatly suppressed with the proposed BFCL. Another significant feature of this work is that the performance of the proposed BFCL in VSC-HVDC systems is compared to that of series dynamic braking resistor (SDBR. Comparative results show that the proposed BFCL is superior over SDBR in limiting fault current as well as improving system fault ride through (FRT capability.

  7. 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.

  8. 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...

  9. 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,...

  10. Head and pelvic movement asymmetries at trot in riding horses in training and perceived as free from lameness by the owner

    Science.gov (United States)

    Egenvall, Agneta; Haubro Andersen, Pia; Pfau, Thilo

    2017-01-01

    Recent studies evaluating horses in training and considered free from lameness by their owners have identified a large proportion of horses with motion asymmetries. However the prevalence, type and magnitude of asymmetries when trotting in a straight line or on the lunge have not been investigated. The aim of this study was to objectively investigate the presence of motion asymmetries in riding horses in training by identifying the side and quantifying the degree and type (impact, pushoff) of forelimb and hind limb asymmetries found during straight line trot and on the lunge. In a cross-sectional study, vertical head and pelvic movement symmetry was measured in 222 Warmblood type riding horses, all without perceived performance issues and considered free from lameness by their owners. Body-mounted uni-axial accelerometers were used and differences between maximum and minimum head (HDmax, HDmin) and pelvic (PDmax, PDmin) vertical displacement between left and right forelimb and hind limb stances were calculated during straight line trot and on the lunge. Previously reported symmetry thresholds were used. The thresholds for symmetry were exceeded in 161 horses for at least one variable while trotting in a straight line, HDmin (n = 58, mean 14.3 mm, SD 7.1), HDmax (n = 41, mean 12.7 mm, SD 5.5), PDmax (n = 87, mean 6.5 mm, SD 3.10), PDmin (n = 79, mean 5.7 mm, SD 2.1). Contralateral and ipsilateral concurrent forelimb and hind limb asymmetries were detected in 41 and 49 horses, respectively. There was a linear association between the straight line PDmin values and the values on the lunge with the lame limb to the inside of the circle. A large proportion (72.5%) of horses in training which were perceived as free from lameness by their owner showed movement asymmetries above previously reported asymmetry thresholds during straight line trot. It is not known to what extent these asymmetries are related to pain or to mechanical abnormalities. Therefore, one of the most

  11. About the Little Red Riding Hood, Durex and anger: production, meaning and reception of one fairy tale and one commercial ad

    Directory of Open Access Journals (Sweden)

    Dragana Antonijević

    2016-03-01

    Full Text Available By applying the semiological analysis, this paper considers planned and unplanned readings of a provocative domestic commercial, which, in order to convey its message, transposed the Little Red Riding Hood’s character in accordance with the advertised product – Durex condoms. This commercial caused furious reactions of parents who took legal action for breaching the Law on public advertising and, especially, "harming children’s sensibility and integrity". Provocative billboards also caused numerous comments in the daily newspapers, in the Internet chat rooms, with some considering the commercial vulgar and offensive and others having no problem with it, adding that the ones who took offence belonged to those puritan and conservative layers of the society. In order to discover the reasons to this kind of reactions, I started with researching how the commercial was made and what kind of message it offered. Next, I reconsidered the meaning of the very fairy tale "The Red Riding Hood". Its original version, which contains open sexual allusions, is quite different to the changed versions offered by Charles Perrault and the Grimm brothers. Their versions can be seen as fakelore, since they outrageously intervened on the plot and the meaning of the original fairy tale. However, since the Grimm brothers’ version is the most popular, it is a fact that our public reacted with such anger led by the meaning of their version, which accentuates overeating and cannibalism, and not sexual development of girls, which is the basic message of the original version. This is where the "communicational noise" that led to those negative reactions came from. By discovering the true meaning of the tale, the answer is given to the question whether the advertising agency made a slip up, or it had actually found the right way to communicate the hidden message of the tale, and at the same time ruin the advertising campaign for which it was used. In the end, range and

  12. Use of a virtual reality physical ride-on sailing simulator as a rehabilitation tool for recreational sports and community reintegration: a pilot study.

    Science.gov (United States)

    Recio, Albert C; Becker, Daniel; Morgan, Marjorie; Saunders, Norman R; Schramm, Lawrence P; McDonald, John W

    2013-12-01

    Participation in sailing by people with disabilities, particularly in small sailboats, is widely regarded as having positive outcomes on self-esteem and general health for the participants. However, a major hurdle for people with no previous experience of sailing, even by those without disabilities, is the perception that sailing is elitist, expensive, and dangerous. Real-time "ride-on" sailing simulators have the potential to bridge the gap between dry-land and on-the-water sailing. These provide a realistic, safe, and easily supervised medium in which nonsailors can easily and systematically learn the required skills before venturing out on the water. The authors report a 12-wk pilot therapeutic sailing program using the VSail-Access sailing simulation system followed by on-water experience. After completion of the training, all subjects demonstrated the ability to navigate a simple course around marker buoys (triangular configuration) on the computer screen, the ability to sail independently in winds of moderate strength (up to 14 knots) on water, and measurable improvements in their psychologic health. In addition, the subjects were able to participate in a sports activity with their respective family members and experienced a sense of optimism about their future.

  13. Resolução de um caso real do problema dial-a-ride multicritério via clustering search

    Directory of Open Access Journals (Sweden)

    Patrícia Perretto Rodrigues

    2014-09-01

    Full Text Available Este artigo apresenta um clustering search (CS para o problema dial-a-ride (DARP multicritério presente na cidade de Vitória (ES. Em Vitória, os usuários especificam requisições de transporte entre origens e destinos com janelas de tempo para os horários de embarque e desembarque; o transporte é realizado por uma frota homogênea de veículos localizados inicialmente em uma mesma garagem; busca-se assim definir um conjunto de rotas de atendimento que minimize o custo de transporte (normalmente, tempo ou distância, o número de veículos utilizados e o tempo total de espera dos usuários, respeitando restrições como as de capacidade dos veículos e de precedência (o embarque de um usuário deve preceder o seu destino em uma rota. Dessa forma, o CS aqui proposto foi capaz de tratar as particularidades do caso de Vitória, ES. Bons resultados computacionais são apresentados considerando instâncias reais obtidas na Secretaria de Transportes, Trânsito e Infraestrutura Urbana de Vitória, ES.

  14. The effect of robo-horseback riding therapy on spinal alignment and associated muscle size in MRI for a child with neuromuscular scoliosis: an experimenter-blind study.

    Science.gov (United States)

    Lee, Dong Ryul; Lee, Nam Gi; Cha, Hyun Jung; Yun Sung, O; You, Sung Joshua Hyun; Oh, Jin Hwan; Bang, Hyo Seong

    2011-01-01

    This case study was conducted to highlight the clinical and radiological features of a patient with progressive neuromuscular scoliosis before and after robo-horseback riding therapy (HBRT). A clinical, laboratory, and radiological analysis of a single case. An 11-year-old child, dignosed right thoracolumbar neuromuscular scoliosis secondary to cerebral palsy. The child received a 5-week course of robo-HBRT, comprising of 60-minute periods a day, five times a week. Postural alignment was determined by Cobb's method. A real-time magnetic resonance imaging (MRI) was performed to determine the robo-HBRT-induced changes in cross-sectional area (CSA) of bilateral thoracic (T2) and lumbar (L2) paraspinalis. Clinical tests including the standard Gross Motor Function Measure (GMFM) and manual muscle testing (MMT) with the Lafayette Manual Muscle Tester were used to compare the intervention-related changes in motor performance and power. The surface EMG was also used to examine therapy-induced changes in muscle activity amplitude for bilateral T2 and L2 paraspinalis and rectus abdominis muscles. Clinical motor and strength scores increased after the intervention. Radiographic Cobb's angle, MRI, and electromyographic amplitude data demonstrated notably enhanced spinal alignment and muscle fiber CSA and symmetry, respectively. This is the first study to provide evidence of the therapeutic efficacy of a novel form of robo-HBRT on motor function and associated structural and motor control improvements, thus suggesting a method of augmenting therapy in neuromuscular scoliosis.

  15. El Calloviense de los Ibérides (dominio Ibérico, España. Síntesis bioestratigráfica

    Directory of Open Access Journals (Sweden)

    Meléndez, G.

    1987-04-01

    Full Text Available More than 60 Callovian geological profiles in the Iberides (between Burgos and Alicante have been studied. The Ricla (Zaragoza Callovian section as reference biostratigraphic outline has been established, documenting almost all Callovian Mesogean Zones and Subzones and many biohorizons. The others profiles in relation with the elected as reference are briefly described, standing out the scarce thickness and Upper Callovian and frequently Middle Callovian absence.Se han estudiado más de 60 perfiles geológicos de edad Calloviense en los Ibérides (entre Burgos y Alicante. El Calloviense de Ricla (Zaragoza se toma como esquema bioestratigráfico de referencia, documentándose casi todas las zonas y subzonas y muchos de los biohorizontes del Calloviense de la Mesogea. Los demás perfiles se describen sumariamente en relación al elegido como referencia, destacando su escasa potencia y la falta de Calloviense superior y frecuentemente de Calloviense medio.

  16. 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.)

  17. Genetic diversity in German draught horse breeds compared with a group of primitive, riding and wild horses by means of microsatellite DNA markers.

    Science.gov (United States)

    Aberle, K S; Hamann, H; Drögemüller, C; Distl, O

    2004-08-01

    We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (H(o)) differed little among the heavy horse breeds (0.64-0.71), but was considerably lower than in the Hanoverian Warmblood or Icelandic Horse population. The mean number of alleles (N(A)) decreased more markedly with declining population sizes of German draught horse breeds (5.2-6.3) but did not reach the values of Hanoverian Warmblood (N(A) = 6.7). The coefficient of differentiation among the heavy horse breeds showed 11.6% of the diversity between the heavy horse breeds, as opposed to 21.2% between the other horse populations. The differentiation test revealed highly significant genetic differences among all draught horse breeds except the Mecklenburg and Saxon Thuringa Coldbloods. The Schleswig Draught Horse was the most distinct draught horse breed. In conclusion, the study demonstrated a clear distinction among the German draught horse breeds and even among breeds with a very short history of divergence like Rhenish German Draught Horse and its East German subpopulations Mecklenburg and Saxon Thuringa Coldblood.

  18. Effect of guideway discontinuities on magnetic levitation and drag forces

    International Nuclear Information System (INIS)

    Rossing, T.D.; Korte, R.; Hull, J.R.

    1991-01-01

    Transients in the lift and drag forces on a NdFeB permanent magnet were observed as the magnet passed over various discontinuities in a rotating aluminum disk at velocities of 4 to 25 m/s. For full cuts in the disk, the amplitude of the lift and drag transients and the wave form of the drag transient depend on the width, and the amplitudes are much larger than for partial cuts. The use of a backing plate to join two cut segments is ineffective

  19. Quality Guidelines

    Science.gov (United States)

    ... this page: https://medlineplus.gov/criteria.html MedlinePlus Quality Guidelines To use the sharing features on this ... materials must also meet our existing quality guidelines. Quality, authority and accuracy of health content The organization's ...

  20. 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.

  1. Managing Quality

    CERN Document Server

    Kelemen, Mihaela L

    2002-01-01

    Managing Quality provides a comprehensive review and critical analysis of quality management discourses and techniques by drawing on a number of management disciplines such as operations management, HRM, organizational behaviour, strategy, marketing and organization theory. The book: - introduces readers to key concepts and issues in quality management - provides an overview of both managerial and critical perspectives on quality management - presents the 'wisdom' of quality management gurus - documents the way quality is pursued in manufacturing, service and public sector organizations - comp

  2. Ride comfort optimization of a multi-axle heavy motorized wheel dump truck based on virtual and real prototype experiment integrated Kriging model

    Directory of Open Access Journals (Sweden)

    Bian Gong

    2015-06-01

    Full Text Available The optimization of hydro-pneumatic suspension parameters of a multi-axle heavy motorized wheel dump truck is carried out based on virtual and real prototype experiment integrated Kriging model in this article. The root mean square of vertical vibration acceleration, in the center of sprung mass, is assigned as the optimization objective. The constraints are the natural frequency, the working stroke, and the dynamic load of wheels. The suspension structure for the truck is the adjustable hydro-pneumatic suspension with ideal vehicle nonlinear characteristics, integrated with elastic and damping elements. Also, the hydraulic systems of two adjacent hydro-pneumatic suspension are interconnected. Considering the high complexity of the engineering model, a novel kind of meta-model called virtual and real prototype experiment integrated Kriging is proposed in this article. The interpolation principle and the construction of virtual and real prototype experiment integrated Kriging model were elucidated. Being different from traditional Kriging, virtual and real prototype experiment integrated Kriging combines the respective advantages of actual test and Computer Aided Engineering simulation. Based on the virtual and real prototype experiment integrated Kriging model, the optimization results, obtained by experimental verification, showed significant improvement in the ride comfort by 12.48% for front suspension and 11.79% for rear suspension. Compared with traditional Kriging, the optimization effect was improved by 3.05% and 3.38% respectively. Virtual and real prototype experiment integrated Kriging provides an effective way to approach the optimal solution for the optimization of high-complexity engineering problems.

  3. Riding the rapids: living with autism or disability--an evaluation of a parenting support intervention for parents of disabled children.

    Science.gov (United States)

    Stuttard, Lucy; Beresford, Bryony; Clarke, Susan; Beecham, Jennifer; Todd, Samantha; Bromley, Jo

    2014-10-01

    Evidence on the effectiveness of interventions to support parents of disabled children to manage their child's behaviour problems is limited. The aim of this study was to evaluate a group-delivered intervention (Riding the Rapids) which was specifically developed for parents of a child with a disability or autistic spectrum condition. This programme has been routinely delivered by a community-based mental health team across an urban, multi-ethnic locality for a number of years. A non-randomised controlled study design comprising an intervention group (n=48) and comparator (no intervention) group (n=28) was used to evaluate the effects of the intervention on child behaviour (Eyberg Child Behaviour Inventory; parent-set goals) and parenting efficacy and satisfaction (Parents Sense of Competence Scale) at post-intervention and six-month follow-up. Data on costs to the service provider of delivering the intervention were also collected. Receipt of the intervention was associated with significant reductions in parent-reported behaviour problems and significant improvements in parenting efficacy and satisfaction. At six-month follow-up, progress towards achieving parent-set child behaviour goals and parenting satisfaction had been maintained. Post hoc analysis suggests parents who do not have English as a first language may not benefit as much as other parents from this intervention. Findings suggest this is a promising intervention for parents of a child with a disability that is likely to be less resource intensive to service providers than individually delivered interventions. Limitations and implications for future research are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Product Quality and Worker Quality

    OpenAIRE

    Abowd, John M; Kramarz, Francis

    1995-01-01

    We study the relation between product quality and worker quality using an economic model that, under certain conditions, provides a direct link between product price, product quality and work-force quality. Our measures of product quality are the evolution in the detailed product price relative to its product group, and the level of the product price relative to this group. Our worker quality measures are the firm's average person effect and personal characteristics effect from individual wag...

  6. Product Quality and Worker Quality

    OpenAIRE

    John M. ABOWD; Françis KRAMARZ; Antoine MOREAU

    1996-01-01

    We study the relation between product quality and worker quality using an economic model that, under certain conditions, provides a direct link between product price, product quality and work force quality. Our measures of product quality are the evolution in the detailed product price relative to its product group and the level of the product price relative to this group. Our worker quality measures are the firm's average person effect and personal characteristics effect from individual wage...

  7. Quality Manual

    Science.gov (United States)

    Koch, Michael

    The quality manual is the “heart” of every management system related to quality. Quality assurance in analytical laboratories is most frequently linked with ISO/IEC 17025, which lists the standard requirements for a quality manual. In this chapter examples are used to demonstrate, how these requirements can be met. But, certainly, there are many other ways to do this.

  8. 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

  9. CORRIGENDUM: Atoms riding Rayleigh waves Atoms riding Rayleigh waves

    Science.gov (United States)

    Benedek, G.; Echenique, P. M.; Toennies, J. P.; Traeger, F.

    2010-09-01

    In the original paper the affiliation list is incorrect. The correct address list is as follows: G Benedek1, 5, P M Echenique1, 2, J P Toennies3 and F Traeger4 1 Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018 Donostia—San Sebastián, Spain 2 Departamento de Física de Materiales and CFM (CSIC-UPV/EHU), Universidad del País Vasco/Euskal Herriko Unibertsitatea, E-20018 San Sebastián/Donostia, Spain 3 Max Planck-Institut für Dynamik und Selbstorganisation, Bunsenstraße 10 D-37073 Göttingen, Germany 4 Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum Universitätsstraße 150, 44801 Bochum, Germany 5 Permanent address: Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via Cozzi 53, 20125 Milano, Italy

  10. Dieta vegetariana e níveis de colesterol e triglicérides Vegetarian diet and cholesterol and triglycerides levels

    Directory of Open Access Journals (Sweden)

    Simone Grigoletto De Biase

    2007-01-01

    Full Text Available OBJETIVO: Comparar os valores de triglicérides (TG, colesterol total (CT, lipoproteína de baixa densidade (LDL e lipoproteína de alta densidade (HDL entre indivíduos vegetarianos e onívoros. MÉTODOS: Foram coletadas amostras sangüíneas de 76 indivíduos, de ambos os sexos, que foram separados em quatro grupos de dieta: onívoro, ovolacto, lacto e vegetariano restrito (ou "vegan". Foram dosados: CT, LDL, HDL e TG. RESULTADOS: Para as taxas de CT, LDL e TG, observa-se diferença significante entre as amostras, sendo o maior valor nos onívoros, havendo decréscimo nos vegetarianos, de acordo com o grau de restrição de produtos de origem animal, sendo a menor taxa observada nos "vegans". A média e o desvio padrão do CT foram de 208,09 ± 49,09 mg/dl no grupo de onívoros, e 141,06 ± 30,56 mg/dl no de vegan (p OBJECTIVE: Compare levels of triglyceride (TG, total cholesterol (TC, low density lipoprotein (LDL and high density lipoprotein (HDL among vegetarians and omnivores. METHODS: Blood samples were collected from 76 individuals - both males and females - separated in four different diet groups: omnivores, lacto-ovo vegetarians, lacto vegetarians, and restricted vegetarians (or vegans. Dosing was done for: TC, LDL, HDL and TG. RESULTS: Significant difference was reported for TC, LDL and TG levels among the samples. Higher levels were reported by omnivores, with decreased levels for vegetarians as animal products were restricted, with lowest levels having been reported by vegans. Mean and standard deviation for TC were 208.09 ± 49.09 mg/dl in the group of omnivores, and 141.06 ± 30.56 mg/dl in the group of vegans (p < 0.001. LDL values for omnivores and vegans were respectively: 123.43 ± 42.67 mg/dl and 69.28 ± 29.53 mg/dl (p < 0.001. As for TG, those values were 155.68 ± 119.84 mg/dl and 81.67 ± 81.90 mg/dl (p < 0.01. As for HDL level no difference was reported between the samples, but HDL/TC ratio was significantly higher in

  11. Quality assurance

    International Nuclear Information System (INIS)

    Kunich, M.P.; Vieth, D.L.

    1989-01-01

    This paper provides a point/counterpoint view of a quality assurance director and a project manager. It presents numerous aspects of quality assurance requirements along with analyses as to the value of each

  12. Quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, B.M.; Gleckler, B.P.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the quality assurance and quality control practices of Hanford Site environmental monitoring and surveillance programs. Samples are analyzed according to documented standard analytical procedures. This section discusses specific measures taken to ensure quality in project management, sample collection, and analytical results.

  13. Water quality

    Science.gov (United States)

    Aquatic animals are healthiest and grow best when environmental conditions are within certain ranges that define, for a particular species, “good” water quality. From the outset, successful aquaculture requires a high-quality water supply. Water quality in aquaculture systems also deteriorates as an...

  14. Quality assurance

    International Nuclear Information System (INIS)

    Gillespie, B.M.; Gleckler, B.P.

    1995-01-01

    This section of the 1994 Hanford Site Environmental Report summarizes the quality assurance and quality control practices of Hanford Site environmental monitoring and surveillance programs. Samples are analyzed according to documented standard analytical procedures. This section discusses specific measures taken to ensure quality in project management, sample collection, and analytical results

  15. Basic Regge theory rides again

    International Nuclear Information System (INIS)

    Johnson, R.C.

    1979-01-01

    In this series of lectures Regge theory, which plays a role in high-energy production just as in 2 → 2 processes, is considered. It is shown that exclusive applications and tests are hampered by lack of events and phase space but observation of double Pomeron exchange is encouraging for the multi-Regge Model. In inclusive processes, approximate scaling and its approach are described, including development of a central plateau and limiting fragmentation and triple-Regge behaviour. The Regge picture also sets a natural scale of distance in rapidity for discussion of interparticle correlations. All this understanding involves domination of unphysical multiparticle forward amplitudes by the familiar factorising Regge poles seen directly in 2 → 2 reactions. (UK)

  16. Instant Social Ride-Sharing

    OpenAIRE

    Gidofalvi, Gyözö; Herenyi, Gergely; Bach Pedersen, Torben

    2008-01-01

    This paper explores the use of ride–sharing as a resource-efficient mode of personal transportation. While the perceived benefits of ride–sharing include reduced travel times, transportation costs, congestion, and carbon emissions, its wide–spread adoption is hindered by a number of barriers. These include the scheduling and coordination of routes, safety risks, social discomfort in sharing private spaces, and an imbalance of costs and benefits among parties. To address these barriers, the au...

  17. Biological clocks: riding the tides.

    Science.gov (United States)

    de la Iglesia, Horacio O; Johnson, Carl Hirschie

    2013-10-21

    Animals with habitats in the intertidal zone often display biological rhythms that coordinate with both the tidal and the daily environmental cycles. Two recent studies show that the molecular components of the biological clocks mediating tidal rhythms are likely different from the phylogenetically conserved components that mediate circadian (daily) rhythms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Second Thoughts on Free Riding

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Haagen; Tyran, Jean-Robert Karl; Wengström, Erik Roland

    2014-01-01

    We use the strategy method to classify subjects into cooperator types in a large-scale online Public Goods Game and find that free riders spend more time on making their decisions than conditional cooperators and other cooperator types. This result is robust to reversing the framing of the game...

  19. Second Thoughts on Free Riding

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Haagen; Tyran, Jean-Robert Karl; Wengström, Erik Roland

    We use the strategy method to classify subjects into cooperator types in a largescale online Public Goods Game and nd that free riders spend more time on making their decisions than conditional cooperators and other cooperator types. This result is robust to reversing the framing of the game...

  20. Riding out a Financial Storm

    Science.gov (United States)

    Evans, Randy C.

    2012-01-01

    After two decades of steady growth and financial stability in the Rio Rancho Public Schools, New Mexico's fastest-growing school district found itself face to face with a $3.8 million budget deficit going into the 2008-09 school year. Because people in the district hesitated to change anything that would cut into student programming, and nobody…

  1. Nukem's plutonium hitches a ride

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The European repercussions of a scandal involving the illegal movement of plutonium and cobalt 60 in canisters in which it was claimed there was only low-level radioactive waste, from West Germany to the reprocessing centre at Mol, Belgium are considered. Large bribes were paid to employees of the nuclear industry and government inspectors to allow this illicit transport to carry on over a number of years. It is not yet clear where the plutonium came from or where it was going. The suggestion that it may have been sold to Libya or Pakistan for nuclear weapons is very damaging to the nuclear safety argument. Even if the plutonium was being disposed of because it could not be accounted for, the safeguard procedures do not give confidence to the European public more aware of nuclear safety than ever. (UK)

  2. Microbiological quality of air in free-range and box-stall stable horse keeping systems.

    Science.gov (United States)

    Wolny-Koładka, Katarzyna

    2018-04-07

    The aim of this study was to assess the microbiological quality of air in three horse riding centers differing in the horse keeping systems. The air samples were collected in one facility with free-range horse keeping system and two with box stalls of different sizes. The samples were collected over a period of 3 years (2015-2017), four times per year (spring, summer, autumn, winter) to assess the effect of seasonal changes. The prevalence of aerobic mesophilic bacteria, mold fungi, actinomycetes, Staphylococcus spp., and Escherichia coli was determined by the air collision method on Petri dishes with appropriate microbiological media. At the same time, air temperature, relative humidity, and particulate matter concentration (PM 10 , PM 2.5 ) were measured. It was found that the horse keeping system affects the occurrence of the examined airborne microorganisms. Over the 3-year period of study, higher temperature and humidity, as well as particulate matter concentration-which notoriously exceeded limit values-were observed in the facilities with the box-stall system. The air sampled from the largest horse riding center, with the largest number of horses and the box-stall system of horse keeping, was also characterized by the heaviest microbiological contamination. Among others, bacteria from the following genera: Staphylococcus spp., Streptococcus spp., Bacillus spp., and E. coli and fungi from the genera Aspergillus, Fusarium, Mucor, Rhizopus, Penicillium, Trichothecium, Cladosporium, and Alternaria were identified in the analyzed samples.

  3. Energy quality

    International Nuclear Information System (INIS)

    Stern, David I.

    2010-01-01

    This paper develops economic definitions of energy quality for individual fuels and energy aggregates. There are use- and exchange-value concepts, as well as marginal and total measures, of energy quality. A factor augmentation or quality coefficients approach corresponds to the use-value definition while indicators based on distance functions and relative prices are exchange-value based definitions. These indicators are identical when the elasticity of substitution between fuels is infinity but diverge or cannot be computed for other interfuel elasticities of substitution. When the elasticity of substitution is zero only the quality coefficients approach is defined. I also show that 1) the ratio of an energy volume index to aggregate joules cannot be considered a complete indicator of aggregate energy quality as it does not account for quality changes in the component fuels 2) demand curve integrals do not provide information on relative use-values or fuel qualities when the elasticity of substitution is unity or less. (author)

  4. Energy quality

    Energy Technology Data Exchange (ETDEWEB)

    Stern, David I. [Arndt-Corden Division of Economics, Crawford School of Economics and Government and Centre for Applied Macroeconomic Analysis, Australian National University, Canberra, ACT 0200 (Australia)

    2010-05-15

    This paper develops economic definitions of energy quality for individual fuels and energy aggregates. There are use- and exchange-value concepts, as well as marginal and total measures, of energy quality. A factor augmentation or quality coefficients approach corresponds to the use-value definition while indicators based on distance functions and relative prices are exchange-value based definitions. These indicators are identical when the elasticity of substitution between fuels is infinity but diverge or cannot be computed for other interfuel elasticities of substitution. When the elasticity of substitution is zero only the quality coefficients approach is defined. I also show that 1) the ratio of an energy volume index to aggregate joules cannot be considered a complete indicator of aggregate energy quality as it does not account for quality changes in the component fuels 2) demand curve integrals do not provide information on relative use-values or fuel qualities when the elasticity of substitution is unity or less. (author)

  5. Quality management

    International Nuclear Information System (INIS)

    1989-01-01

    The 1989 Quality Management Conference focusses on process control and the thus achievable product quality. It is shown that the buyers' increasing demands on product quality require appropriate response in terms of enhanced efforts and methods for quality assurance in the production process. The connection between quality targets and the expenditure required is shown, as well as a comparative validation of efficiency of quality assurance methods. The firms selected for representation at this conference cover a wide range of products so that practically the entire scope of process control problems in the various industrial branches is discussed in the conference contributions. The last conference session is concerned with the strategies and technical developments for enhanced combination of quality assurance and control and production processes. (orig./HP) [de

  6. Hippotherapy: quality of life for the elderly on the horse

    Directory of Open Access Journals (Sweden)

    Lia Mara Wibelinger

    2011-09-01

    Full Text Available Hippotherapy is a technique of rehabilitation and education that uses horse riding and equestrian activities to provide physical benefits to the practitioner, psychological, educational and social. This activity requires the participation of the entire body, the practitioner working in a global horse being used as a therapeutic method that will help develop equilibrium, muscle tone, muscle strength, body awareness, improvement of motor coordination, attention, self-confidence, self-esteem and quality of life. Hippotherapy in the elderly will use the horse as a therapeutic agent in treating various pathologies providing welfare and thus improved quality of life, and a pleasurable treatment, because it runs away from offices and indoor environments. Moreover, threedimensional movement, rhythmic rocking horse and will stimulate the vestibular system, the improvement of consciousness space-time, concentration, equilibrium and consolidation of security gravitational leaving the elderly less vulnerable to falls and related disabilities. Therefore, this article literature review aimed to determine the effects and show the importance of the practice of hippotherapy in order to obtain better quality of life and longevity.

  7. Quality management and quality assurance

    International Nuclear Information System (INIS)

    Pieroni, N.

    1991-01-01

    The main common difficulties are presented found in the implementation of effective Quality Management and Quality Assurance Programmes, based on the recommendations of the IAEA International Nuclear Safety Advisory Group, the information collected by the IAEA experts participating in its meetings, and the results of the IAEA Operational Safety Review Team missions. The difficulties were identified in several areas. The most relevant root causes can be characterized as lack of understanding of quality principles and difficulty in implementation by the responsible management. The IAEA programme is described attempting to provide advice and support in the implementation of an effective quality programme through a number of activities including: preparation of practical guidelines, training programmes for management personnel, assistance in building up qualified manpower, and promoting the quest for excellence through the exchange of experience in the implementation of effective Quality Management and Quality Assurance Programmes in nuclear power plants with good performance records. (Z.S.)

  8. Quality assurance

    International Nuclear Information System (INIS)

    Cante; Feger; Genevray; Hennion; Moneyron; Monneyron; Normand; Rastoin; Silberstein; Vaujour.

    1976-01-01

    The general principles of quality assurance and their applications within the French industrial and commercial regulations are presented. The conditions for the practical application of quality assurance to the different stages of the life of a nuclear power station (design, development, operation) are considered and a special mention is made of nuclear fuels and liquid sodium cooled reactors [fr

  9. Afterschool Quality

    Science.gov (United States)

    Smith, Charles; Akiva, Tom; McGovern, Gina; Peck, Stephen C.

    2014-01-01

    This chapter discusses efforts to define and improve the quality of afterschool services, highlighting areas of agreement and identifying leading-edge issues. We conclude that the afterschool field is especially well positioned to deliver high-quality services and demonstrate effectiveness at scale because a strong foundation has been built for…

  10. Measuring Quality

    DEFF Research Database (Denmark)

    Næsby, Torben

    local differences in the quality of day care facilities in Denmark (Nordahl et al, 2012; Hansen et al, 2016) and also that we in fact have little knowledge of whether the desired politically determined targets are being met or not and what the quality is really like. In order to measure the quality......The Danish Day Care Facilities Act (2015), which provides the curriculum on which day care education is based, does not stipulate very clearly what children should learn and therefore how educational processes in preschools should be organised. This means that we must accept that there are large...... of preschool in Denmark a new research project using the ECERS 3 instrument has been launched. This could capture quality from a global quality standard’s perspective, building the basis for a further investigation of practice in Danish early childhood provisions and centers in a more narrow approach...

  11. Quality assurance

    International Nuclear Information System (INIS)

    1996-01-01

    The main efforts of Nuclear Regulatory Authority of the Slovak Republic (NRA SR) was focused on support of quality assurance programmes development at responsible organizations Bohunice V-1 and V-v and Mochovce NPPs and their inspection. Development of the level two documentation of a partial quality assurance programme for NPP operation continued at Mochovce NPP. Most of documentation has been submitted to NRA SR for comments and approval. NRA SR invited a mission of French experts to Mochovce NPP to review preparation and performance of internal audits that would be beneficial for improvement in this kind activities at the NPP. Bohunice NPP continued in development of a partial quality assurance programme for operation. The Quality Assurance Programme submitted to NRA SR for approval. Based on a request of Bohunice NPPs, NRA SR consulted the draft quality assurance programme developed by Siemens for stage of the 'Basic Design' of V-1 NPP upgrading. The programme had not been submitted for approval to NRA SR prior to completion of works by Siemens. Based on an internal audit that had been performed, corrective measures were proposed to meet requirements on review and approval of suppliers quality assurance programmes. Requirements related to the quality assurance at nuclear installations were prepared to be incorporated into principles of a act on peaceful use of nuclear power in Slovak Republic

  12. Quality indicators

    DEFF Research Database (Denmark)

    Hjorth-Andersen, Christian

    1991-01-01

    In recent literature it has been suggested that consumers need have no knowledge of product quality as a number of quality indicators (or signals) may be used as substitutes. Very little attention has been paid to the empirical verification of these studies. The present paper is devoted...... to the issue of how well these indicators perform, using market data provided by consumer magazines from 3 countries. The results strongly indicate that price is a poor quality indicator. The paper also presents some evidence which suggests that seller reputation and easily observable characteristics are also...

  13. Quality assurance and product quality

    International Nuclear Information System (INIS)

    Lacroix, D.; Bastiani, P. de

    2004-01-01

    The basic quality assurance requirements have to be completed by means that are oriented towards the quality of products; in COGEMA LOGISTICS our approach is based on four principles: 1) an integrated management system: Quality, health and safety, environment 2) an organization based on the responsibility of all actors, trust and transparency 3) a methodical approach to continuously improve the methods that are employed to achieve quality: -process management -corrective and preventive actions -self assessments and various surveys 4) but at the same time strong procedures for control and monitoring of all activities: -technical and quality audits (external and internal) -at source inspections -engineering activities inspections This performance-based approach is necessary to guaranty the effectiveness of the traditional formal QA means

  14. Quality management

    OpenAIRE

    Forrest, Diana

    1997-01-01

    scen Scenario Interactive Media Element This mini-case study walks users through a scenario and user must make business decisions for a company that looks at the issues of quality and cost. GB3042 Operations Management

  15. Ocean Quality

    OpenAIRE

    Brevik, Roy Schjølberg; Jordheim, Nikolai; Martinsen, John Christian; Labori, Aleksander; Torjul, Aleksander Lelis

    2017-01-01

    Bacheloroppgave i Internasjonal Markedsføring fra ESADE i Spania, 2017 In this thesis we were going to answer the problem definition “which segments in the Spanish market should Ocean Quality target”. By doing so we started to collect data from secondary sources in order to find information about the industry Ocean Quality are operating in. After conducting the secondary research, we still lacked essential information about the existing competition in the aquaculture industry o...

  16. Quality assurance

    OpenAIRE

    Cauchi, Maurice A.M.

    1993-01-01

    The concept of quality assurance refers more specifically to the process of objectifying and clearly enunciating goals, and providing means of assessing the outcomes. In this article the author mentions four fundamental elements of quality assurance which should be applied in the medical profession in Malta. These elements should relate to professional performance, resource utilisation, risk management and patient satisfaction. The aim of the medical professionals in Malta is to provide the b...

  17. Test quality

    International Nuclear Information System (INIS)

    Hartley, R.S.; Keller, A.E.

    1992-01-01

    Inservice testing of safety-related components at nuclear power plants is performed under the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the Code). Subsections IWP and IWV of Section 11 of the Code state test method and frequency requirements for pumps and valves, respectively. Tests vary greatly in quality and frequency. This paper explores the concept of test quality and its relationship with operational readiness and preventive maintenance. This paper also considers the frequencies of component testing. Test quality is related to a test's ability to detect degradation that can cause component failure. The quality of the test depends on several factors, including specific parameters measured, system or component conditions, and instrument accuracy. The quality of some currently required tests for check valves, motor-operated valves, and pumps is also discussed. Suggestions are made to improve test quality by measuring different parameters, testing valves under load, and testing positive displacement pumps at high pressure and centrifugal pumps at high flow rate conditions. These suggestions can help to improve the level of assurance of component operational readiness gained from testing

  18. Test quality

    International Nuclear Information System (INIS)

    Hartley, R.S.; Keller, A.E.

    1992-01-01

    This document discusses inservice testing of safety-related components at nuclear power plants which is performed under the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the Code). Subsections IWP and IWV of Section XI of the Code state test method and frequency requirements for pumps and valves respectively. Tests vary greatly in quality and frequency. This paper explores the concept of test quality and its relationship with operational readiness and preventive maintenance. This paper also considers the frequencies of component testing. Test quality is related to a test's ability to detect degradation that can cause component failure. The quality of the test depends on several factors, including specific parameters measured, system or component conditions, and instrument accuracy. The quality of some currently required tests for check valves, motor-operated valves, and pumps is also discussed. Suggestions are made to improve test quality by measuring different parameters, testing valves under load, and testing positive displacement pumps at high pressure and centrifugal pumps at high flow rate conditions. These suggestions can help to improve the level of assurance of component operational readiness gained from testing

  19. Quality Management, Quality Assurance and Quality Control in Blood Establishments

    OpenAIRE

    Bolbate, N

    2008-01-01

    Quality terms and the roots of the matter are analyzed according to European Committee’s recommendations. Essence of process and product quality control as well as essence of quality assurance is described. Quality system’s structure including quality control, quality assurance and management is justified in the article.

  20. Quality assurance and quality control

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The practice of nuclear diagnostic imaging requires an appropriate quality assurance program to attain high standards of efficiency and reliability. The International Atomic Energy Agency defines the term quality assurance as ''the closeness with which the outcome of a given procedure approaches some ideal, free from all errors and artifacts.'' The term quality control is used in reference to the specific measures taken to ensure that one particular aspect of the procedure is satisfactory. Therefore, quality assurance is a hospital-wide concept that should involve all aspects of clinical practice. Quality control is concerned with the submission of requests for procedures; the scheduling of patients; the preparation and dispensing of radiopharmaceuticals; the protection of patients, staff, and the general public against radiation hazards and accidents caused by radioactive materials or by faulty equipment; the setting up, use, and maintenance of electronic instruments; the methodology of the actual procedures; the analysis and interpretation of data; the reporting of results; and, finally, the keeping of records. The chapter discusses each of these areas

  1. Environmental Quality

    Science.gov (United States)

    Abelson, Philip H.

    1972-01-01

    Data from the Third Annual Report of the United States Council of Environmental Quality are used in an editorial advocating the use of some of the money committed to cleaning air and water to create a more adequate knowledge base for action. (AL)

  2. Quality guidance and quality formation

    DEFF Research Database (Denmark)

    Poulsen, Carsten Stig; Juhl, Hans Jørn; Kristensen, Kai

    1996-01-01

    set on Danish butter cookies. Five plausible models of the relation between expectation, experience and perceived product quality are estimated. Finally one model is selected on the basis of three criteria: chi-square, RMSEA and AIC: The results show a model where expectations are indirectly related...

  3. PREFAB QUALITY

    DEFF Research Database (Denmark)

    Wraber, Ida Kristina

    This PhD project is a co-financed project between the Danish Forest and Nature Agency, the single family house producer Hjem, and the Department of Architecture & Design at Aalborg University. The aim of the thesis is to investigate the architectural pros and cons as well as the potential...... dwellings as well as testing and challenging the model for analysis of architectural quality as such. The second analysis should show the pros, cons and potential of building prefab wooden dwellings in Denmark in a wider sense, emphasising different methods of manufacturing and approaches to the degree......, technology and site (common abilities, needs, dreams, memories and associations), and it is proposed that the more layers and perspectives that are added to the discussion, the fuller the view of the architectural quality will get. In relation to building prefab wooden dwellings in a Danish context, two...

  4. quality control

    International Nuclear Information System (INIS)

    Skujina, A.; Purina, S.; Riekstina, D.

    1999-01-01

    The optimal objects: soils, spruce needles and bracken ferns were found for the environmental monitoring in the regions of possible radioactive contamination - near SalaspiIs nuclear reactor and Ignalina nuclear power plant. The determination of Sr-90 was based on the radiochemical separation of Sr-90 (=Y-90) by HDEHP extraction and counting the Cerenkov radiation. The quality control of the results was carried out. (authors)

  5. Quality factors

    International Nuclear Information System (INIS)

    Kerr, G.D.

    1986-01-01

    The quality factor, Q, is a dimensionless modifier used in converting absorbed dose, expressed in rads (or grays), to dose equivalent, expressed in rems (or seiverts). The dose equivalent is used in radiation protection to account for the biological effectiveness of different kinds of radiation. The quality factor is related to both the linear energy transfer (LET) and relative biological effectiveness (RBE). The RBE's obtained from biological experiments depend in a complex way on the observed biological effect, the specific test organism, and the experimental conditions. Judgement is involved, therefore, in the choice of the quality factor. Questions regarding the adequacy of current Q values for neutrons were raised first in a 1980 statement by the National Council on Radiation Protection (NCRP) and later in a 1985 statement by the International Commission on Radiological Protection (ICRP). In 1980, the NCRP alerted the technical community to possible future increases between a factor of three and ten in the Q for neutrons, and in 1985, the ICRP suggested an increase by a factor of two in Q for neutrons. Both the ICRP and NRCP are now recommending essentially the same guidance with regard to Q for neutrons: an increase by a factor of two. The Q for neutrons is based on a large, albeit unfocused, body of experimental data. In spite of the lack of focus, the data supporting a change in the neutron quality factor are substantial. However, the proposed doubling of Q for neutrons is clouded by other issues regarding its application. 33 refs., 4 figs., 6 tabs

  6. Air quality

    CSIR Research Space (South Africa)

    Thambiran, Tirusha

    2017-12-01

    Full Text Available ., Blaikie, P., Cannon, T. & Davis, I. 2004. At risk: Natural hazards, people’s vulnerability, and disasters (2nd edition). London: Routledge. Ziervogel, G. & Calder R. 2003. Climate variability and rural livelihoods: Assessing the impact of seasonal... Julia Mambo Kristy Faccer 4 | Global Change Global Change Global Change Global Change | i the quality of research being conducted in South Africa. In addition, South African academics occupy key positions in the Future Earth initiative...

  7. Air quality

    International Nuclear Information System (INIS)

    1995-01-01

    This chapter of the 'Assessment of the state of the environment in Lebanon' describes the air quality and identifies the most important air quality issues. Baseline information about the factors affecting dispersion and the climate of Lebanon presents as well and overall estimation of total emissions in Lebanon. Emissions from vehicles, electricity and power plants generation are described. Industrial emitters of air pollutants are described for each kind of industry i.e.cement plants, Selaata fertilizer factory, sugar-beet factory, refineries and for those derived from the use of leaded fuel . Impact of economic and human activities on air quality in Lebanon (especially in Beirut and Tripoli) are quantified by quantities of CO 2 , SO 2 , NO x , total suspended particulates(TSP), deposition and their environmental effects on health. In abscence of emissions monitoring, data available are expressed in terms of fuel use, output and appropriate empirical factors, national output and workfores sizes. Finally key issues and some potential mitigation /management approaches are presented

  8. REDUÇÃO DE NÍVEIS DE OLIGOSSACÁRIDES EM “IOGURTE” DE SOJA PELO USO DE CULTURAS LÁTICAS

    Directory of Open Access Journals (Sweden)

    ELIZEU ANTôNIO ROSSI

    2007-02-01

    Full Text Available O Streptococcus thermophilus e o Lactobacillus bulgaricus, microorganismos tradicionalmente empregados na elaboração de iogurtes, não são capazes de reduzir satisfatoriamente os níveis de oligossacárides de “iogurtes” preparados à base de soja. Em razão disso, verificou-se o efeito da substituição e/ou associação dessas culturas láticas com culturas de Lactobacillus fermenti e Lactobacillus acidophilus. Nos diversos produtos obtidos foram determinados os níveis de estaquiose, rafinose e sacarose, além da aceitabilidade geral e textura (avaliações sensoriais, viscosidade e consistência. Foi também verificado o tempo de fermentação de cada produto. Com relação à estaquiose, os níveis encontrados nos “iogurtes” de soja representaram de 98 a 115% do nível original do meio de fermentação. A rafinose não foi detectada em nenhum dos produtos, enquanto a sacarose sofreu reduções que variaram de 55,5% a 68,0% do conteúdo inicial. Vários açúcares simples, dentre eles a galactose, foram verificados nos diferentes produtos acabados. Os resultados mostraram que a modificação do inóculo convencional de iogurte (S. thermophilus + L. bulgaricus, através de substituição ou associação com culturas de L. fermenti e L. acidophilus, não se mostrou como alternativa válida no sentido de reduzir oligossacárides. Por outro lado, nos produtos onde o L. bulgaricus foi substituído, verificou-se um significativo aumento do tempo de fermentação.

  9. Primer on Water Quality

    Science.gov (United States)

    ... water quality. What do we mean by "water quality"? Water quality can be thought of as a measure ... is suitable for a particular use. How is water quality measured? Some aspects of water quality can be ...

  10. Quality assurance and quality control

    International Nuclear Information System (INIS)

    Kaden, W.

    1986-01-01

    General preconditions and methods for QA work in the nuclear field are analysed. The application of general QA principles to actual situations is illustrated by examples in the fields of engineering and of the manufacturing of mechanical and electrical components. All QA measures must be fitted to the complexity and relevance of the work steps, which are under consideration. The key to good product quality is the control of working processes. The term 'controlled process' is discussed in detail and examples of feed back systems are given. The main QA measures for the operation of nuclear power plants include the establishment of a Quality Assurance Program, training and qualification of personnel, procurement control, inspection and tests, reviews and audits. These activities are discussed. (orig.)

  11. Quality guaranteed theory

    International Nuclear Information System (INIS)

    Hwang, Ui Cheol

    1988-08-01

    This book tells of introduction of quality guaranteed theory like definition of quality and quality management, quality guaranteed, requirement of quality guaranteed, contrast of QA and QC, quality of guaranteed object, activity of quality guaranteed, set-up of quality that is naturally supposed such as quality guaranteed in plan and design, check of quality guaranteed, order of claim processing and cases of claim management.

  12. Quality assurance

    International Nuclear Information System (INIS)

    Hiller, G.H.

    1979-01-01

    This compendium intends to give fast bibliographic information and to fill the visible gap between documentation and general bibliographic information. The reader is given an outline of quality assurance and some examples of techniques from the relevant literature. The practical engineer, who is always short of time, is thus offered a quick survey and a fast deepening of his understanding by means of literature dealing specifically with his unresolved problems. The mansucript has been kept in tis original form in order to speed up tis publication. The RKW technical department limited itself to checking its contents and the adherence to the established information goals. (orig.) 891 RW/orig. 892 MB [de

  13. “I Am the Wolf: Queering ‘Little Red Riding Hood’ and ‘Snow White and Rose Red’ in the Television Show Once Upon a Time”

    Directory of Open Access Journals (Sweden)

    Brittany Warman

    2016-06-01

    Full Text Available In season one, episode 15 of the television show Once Upon a Time, viewers are given a glimpse into the history of Ruby/Red, the series’ version of Red Riding Hood. The episode reveals that, contrary to most oral and written versions of the ATU 333 tale, Red herself is the wolf: a werewolf who must wear an enchanted red cloak in order to keep from turning into a monster. The episode also features the beginnings of the close friendship between Red and Snow White. The sisterly bond that quickly forms between the two women, combined with the striking images of their respective red and white cloaks, easily calls to mind a less familiar fairy tale not explicitly referenced in the series: “Snow White and Rose Red” (ATU 426. Taking queer readings of this text as starting points, I argue that this allusion complicates the bond between the two women, opening up space for a compelling reading of Red’s werewolf nature as a coded depiction of her then latent but later confirmed bisexuality.

  14. The Concepts of Quality, Quality Assurance and Quality Enhancement

    Science.gov (United States)

    Elassy, Noha

    2015-01-01

    Purpose: This paper aims to critically review and discuss different definitions of the concepts of quality, quality assurance (QA) and quality enhancement (QE) in higher education (HE) with presenting critical perspectives of the literature. Design/methodology/approach: The paper looks at literature concerns with the meaning of quality, QA and QE,…

  15. 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....

  16. The quality cost loop in quality assurance

    International Nuclear Information System (INIS)

    Grabowski, S.P.

    1979-01-01

    A system to determine quality cost is described which solves two major problems: - Determination of quality cost with sufficient accuracy in consideration of rentability - Implementation of quality cost in cost accounting. (RW) [de

  17. Internet quality management

    International Nuclear Information System (INIS)

    Park, Yeong Taek; Song, Hae Geun

    2000-09-01

    This book guides the useful application of internet quality management. It mentions understanding of modern quality management, which includes basics of quality management, six sigma quality innovation, best system, search way of quality information, consideration for effective information search, establishment of quality information center using bookmark, sites related quality by fields, journal sites related quality, sites related quality award,and web sites of the highest business.

  18. Quality function deployment

    International Nuclear Information System (INIS)

    1981-10-01

    This book indicates quality function deployment with quality and deployment of quality function, process and prospect of quality function deployment and development, product process and conception of quality table, deployment of quality demand, design of quality table and application of concurrent multi design, progress design and quality development, main safe part and management of important function part, quality development and deployment of method of construction, quality deployment and economics, total system of quality function deployment and task of quality function deployment in the present and future.

  19. Quality management using TQC

    International Nuclear Information System (INIS)

    Hwang, Ui Cheol

    1992-03-01

    This book introduces conception on quality and quality management, standardization with meaning, principle and structure of it, and system, company standard for quality management, quality management on planning, organization and operation, quality guarantee with system evaluation and information, policy management on policy, purpose and daily life, quality management on research and development infrastructure, quality management on design and production facilities, statistical method of quality management, control chart and process capability.

  20. Quality. [Quality in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, N [Anadrill HSE, Aberdeen (United Kingdom); Jeffries, J [Dowell UK Training Center, Aberdeen (United Kingdom); Mach, J [Dowell North America, Sugar Land, TX (United States); Robson, M [Schlumberger North America, Sugar Land, TX (United States); Pajot, D [Geco-Prakla, Stavanger (Norway); Harrigan, J; Lebsack, T [Schlumberger Perforating and Testing Center, Rosharon, TX (United States); Mullen, D [Schlumberger South America, Bogota (Colombia); Rat, F [Sedco Forex, Montrouge (France); Theys, P [Schlumberger, Montrouge (France)

    1993-01-01

    What is quality How do you achieve it How do you keep it once you have got it. The answer for industry at large is the three-step hierarchy of quality control, quality assurance and Total quality Management. An overview is given of the history of quality movement, illustrated with examples from Schlumberger operations, as well as the oil industry's approach to quality. An introduction of the Schlumberger's quality-associated ClientLink program is presented. 15 figs., 4 ills., 16 refs.