WorldWideScience

Sample records for spacecraft power bus

  1. Natural gas powered bus

    International Nuclear Information System (INIS)

    Ambuehl, D.; Fernandez, J.

    2003-01-01

    This report for the Swiss Federal Office of Energy presents the results of a project carried out by the Swiss Federal Institute of Technology in Zurich to evaluate the performance of a natural-gas-powered bus in comparison with two diesel buses. The report provides details on the vehicles, their routes and the results of interviews made with both passengers and drivers. Details of measurements made on fuel consumption and pollutant emissions are presented in tabular and graphical form, as are those made on noise emissions inside and outside the vehicles. The conclusions of the project are presented including economic aspects of using gas as a motor fuel. Also, the views of passengers, who were more concerned with comfort aspects, and drivers, who were more interested in technical aspects, are quoted

  2. A study of Schwarz converters for nuclear powered spacecraft

    Science.gov (United States)

    Stuart, Thomas A.; Schwarze, Gene E.

    1987-01-01

    High power space systems which use low dc voltage, high current sources such as thermoelectric generators, will most likely require high voltage conversion for transmission purposes. This study considers the use of the Schwarz resonant converter for use as the basic building block to accomplish this low-to-high voltage conversion for either a dc or an ac spacecraft bus. The Schwarz converter has the important assets of both inherent fault tolerance and resonant operation; parallel operation in modular form is possible. A regulated dc spacecraft bus requires only a single stage converter while a constant frequency ac bus requires a cascaded Schwarz converter configuration. If the power system requires constant output power from the dc generator, then a second converter is required to route unneeded power to a ballast load.

  3. Design and Implementation of Hitl Simulator Coupleing Communications Payload and Software Spacecraft Bus

    Directory of Open Access Journals (Sweden)

    In-Jun Kim

    2003-12-01

    Full Text Available Engineering qualification model payload for a communications and broadcasting satellite(CBS was developed by ETRI from May, 2000 to April, 2003. For the purpose of functional test and verification of the payload, a real-time hardware-in-the-loop(HITL CBS simulator(CBSSIM was also developed. We assumed that the spacecraft platform for the CBSSIM is a geostationary communication satellite using momentum bias three-axis stabilization control technique based on Koreasat. The payload hardware is combined with CBSSIM via Power, Command and Telemetry System(PCTS of Electrical Ground Support Equipment(EGSE. CBSSIM is connected with PCTS by TCP/IP and the payload is combined with PCTS by MIL-STD-1553B protocol and DC harness. This simulator runs under the PC-based simulation environment with Windows 2000 operating system. The satellite commands from the operators are transferred to the payload or bus subsystem models through the real-time process block in the simulator. Design requirements of the CBSSIM are to operate in real-time and generate telemetry. CBSSIM provides various graphic monitoring interfaces and control functions and supports both pre-launch and after-launch of a communication satellite system. In this paper, the HITL simulator system including CBSSIM, communications payload and PCTS as the medium of interface between CBSSIM and communications payload will be described in aspects of the system architecture, spacecraft models, and simulator operation environment.

  4. Historical Mass, Power, Schedule, and Cost Growth for NASA Spacecraft

    Science.gov (United States)

    Hayhurst, Marc R.; Bitten, Robert E.; Shinn, Stephen A.; Judnick, Daniel C.; Hallgrimson, Ingrid E.; Youngs, Megan A.

    2016-01-01

    Although spacecraft developers have been moving towards standardized product lines as the aerospace industry has matured, NASA's continual need to push the cutting edge of science to accomplish unique, challenging missions can still lead to spacecraft resource growth over time. This paper assesses historical mass, power, cost, and schedule growth for multiple NASA spacecraft from the last twenty years and compares to industry reserve guidelines to understand where the guidelines may fall short. Growth is assessed from project start to launch, from the time of the preliminary design review (PDR) to launch and from the time of the critical design review (CDR) to launch. Data is also assessed not just at the spacecraft bus level, but also at the subsystem level wherever possible, to help obtain further insight into possible drivers of growth. Potential recommendations to minimize spacecraft mass, power, cost, and schedule growth for future missions are also discussed.

  5. A new MV bus transfer scheme for nuclear power plants

    International Nuclear Information System (INIS)

    Chang, C.K.

    2015-01-01

    The auxiliary power system of many generating stations consists of offsite power supply system and onsite power supply system, including emergency diesel generators (EDG) to provide secure power to auxiliary loads. If a normal power supply fails to supply power, then the power source is transferred to a standby power supply. In the case of nuclear power plants (NPP), the unit auxiliary transformer (UAT) and standby auxiliary transformer (SAT) - or station service transformer - are installed and powered from 2 offsite power circuits to meet regulatory requirements. The transfer methods of a motor bus from a normal source to a standby source used in power generating stations are fast bus transfer, in-phase transfer, or residual transfer. Fast bus transfer method is the most popular and residual voltage transfer method that is used as a backup in medium voltage buses in general. The use of the advanced technology like open circuit voltage prediction and digital signal processing algorithms can improve the reliability of fast transfer scheme. However, according to the survey results of the recent operation records in nuclear power plants, there were many instances where the fast transfer scheme has failed. To assure bus transfer in any conditions and circumstances, un-interruptible bus transfer scheme utilizing the state of the art medium voltage UPS (Un-interruptible Power Supply) is discussed and elaborated

  6. Lightweight power bus for a baseload nuclear reactor in space

    International Nuclear Information System (INIS)

    Oberly, C.E.; Massie, L.D.; Hoffman, D.J.

    1989-01-01

    Space environmental interactions with the power distribution/power processing subsystem can become a serious problem for power systems rated at 10's to 100's of kilowatts. Utilization of ceramic superconductors at 1000 A/cm/sup 2/, which has already been demonstrated at 77 K in a conductor configuration may eliminate both bus mass and distribution voltage problems in a high power satellite. The analytical results presented here demonstrate that a superconducting coaxial power transmission bus offers significant benefits in reduced distribution voltage and mass

  7. Power requirements for commercial communications spacecraft

    Science.gov (United States)

    Billerbeck, W. J.

    1985-01-01

    Historical data on commercial spacecraft power systems are presented and their power requirements to the growth of satellite communications channel usage are related. Some approaches for estimating future power requirements of this class of spacecraft through the year 2000 are proposed. The key technology drivers in satellite power systems are addressed. Several technological trends in such systems are described, focusing on the most useful areas for research and development of major subsystems, including solar arrays, energy storage, and power electronics equipment.

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

    OpenAIRE

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

    2014-01-01

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

  9. A historical overview of the electrical power systems in the US manned and some US unmanned spacecraft

    Science.gov (United States)

    Maisel, J. E.

    1984-01-01

    A historical overview of electrical power systems used in the U.S. manned spacecraft and some of the U.S. unmanned spacecraft is presented in this investigation. A time frame of approximately 25 years, the period for 1959 to 1984, is covered in this report. Results indicate that the nominal bus voltage was 28 volts dc in most spacecraft and all other voltage levels were derived from this voltage through such techniques as voltage inversion or rectification, or a combination. Most spacecraft used solar arrays for the main source of power except for those spacecraft that had a relatively short flight duration, or deep spaceprobes that were designed for very long flight duration. Fuel cells were used on Gemini, Apollo, and Space Shuttle (short duration flights) while radioisotope thermoelectric generators were employed on the Pioneer, Jupiter/Saturn, Viking Lander, and Voyager spacecraft (long duration flights). The main dc bus voltage was unregulated on the manned spacecraft with voltage regulation provided at the user loads. A combination of regulated, semiregulated, and unregulated buses were used on the unmanned spacecraft depending on the type of load. For example, scientific instruments were usually connected to regulated buses while fans, relays, etc. were energized from an unregulated bus. Different forms of voltage regulation, such as shunt, buck/boot, and pulse-width modulated regulators, were used. This report includes a comprehensive bibliography on spacecraft electrical power systems for the space programs investigated.

  10. Research on spacecraft electrical power conversion

    Science.gov (United States)

    Wilson, T. G.

    1983-01-01

    The history of spacecraft electrical power conversion in literature, research and practice is reviewed. It is noted that the design techniques, analyses and understanding which were developed make today's contribution to power computers and communication installations. New applications which require more power, improved dynamic response, greater reliability, and lower cost are outlined. The switching mode approach in electronic power conditioning is discussed. Technical aspects of the research are summarized.

  11. Artificial Intelligence and Spacecraft Power Systems

    Science.gov (United States)

    Dugel-Whitehead, Norma R.

    1997-01-01

    This talk will present the work which has been done at NASA Marshall Space Flight Center involving the use of Artificial Intelligence to control the power system in a spacecraft. The presentation will include a brief history of power system automation, and some basic definitions of the types of artificial intelligence which have been investigated at MSFC for power system automation. A video tape of one of our autonomous power systems using co-operating expert systems, and advanced hardware will be presented.

  12. Optimum power quality service in multi-bus microgrid systems

    DEFF Research Database (Denmark)

    Meng, Lexuan; Guerrero, Josep M.

    2017-01-01

    Power quality requirements for different consumers and electric equipment are distinguished. Conventionally a common power quality standard is applied to the whole power grid inducing debate between several sides, including consumers, generation sites and technical commissions. Customized power...... quality standard settings for different consumers become a widely accepted solution. The main challenge is on the proper regulation of power quality in different areas. This paper considers a multi-bus microgrid system where the power quality in each has flexible and individual standard. Distributed...... generators are utilized to provide power quality regulation functions. An optimization method based strategy is proposed and implemented with the power converter control system. A general mathematical model is established which can be used in the optimization problem for evaluating the objective function...

  13. Manned spacecraft electrical power systems

    Science.gov (United States)

    Simon, William E.; Nored, Donald L.

    1987-01-01

    A brief history of the development of electrical power systems from the earliest manned space flights illustrates a natural trend toward a growth of electrical power requirements and operational lifetimes with each succeeding space program. A review of the design philosophy and development experience associated with the Space Shuttle Orbiter electrical power system is presented, beginning with the state of technology at the conclusion of the Apollo Program. A discussion of prototype, verification, and qualification hardware is included, and several design improvements following the first Orbiter flight are described. The problems encountered, the scientific and engineering approaches used to meet the technological challenges, and the results obtained are stressed. Major technology barriers and their solutions are discussed, and a brief Orbiter flight experience summary of early Space Shuttle missions is included. A description of projected Space Station power requirements and candidate system concepts which could satisfy these anticipated needs is presented. Significant challenges different from Space Shuttle, innovative concepts and ideas, and station growth considerations are discussed. The Phase B Advanced Development hardware program is summarized and a status of Phase B preliminary tradeoff studies is presented.

  14. Development of bus duct inspection robot at nuclear power plant

    International Nuclear Information System (INIS)

    Hamada, Mamoru; Hoshi, Teruaki; Komura, Yoshinari

    2017-01-01

    Under the present situation, nuclear power plant has some places which are inspected with difficulty or not inspected due to narrowness or physical restriction, when carrying out periodical inspection. The subject of our research and development is to improve the accuracy of inspection and also to save labor (liberation from distress work of the worker) by applying a robot technology to the periodical inspection of the nuclear power plant. As a specific example, we report that developed robot can inspect inside the narrow space of Isolated Phase Bus ducts, which connect between a turbine generator and the main transformer. (author)

  15. Converter Power Density Increase using Low Inductive Integrated DC-link Capacitor/Bus

    DEFF Research Database (Denmark)

    Trintis, Ionut; Franke, Toke; Rannested, Bjørn

    2015-01-01

    The power losses in switching devices have a direct effect on the maximum converter power. For a voltage source converter, the DC-link bus has a major influence on the power loss and safe operating area of the power devices. The Power Ring Film CapacitorTM integrated with an optimized bus structu...

  16. Improved techniques for predicting spacecraft power

    International Nuclear Information System (INIS)

    Chmielewski, A.B.

    1987-01-01

    Radioisotope Thermoelectric Generators (RTGs) are going to supply power for the NASA Galileo and Ulysses spacecraft now scheduled to be launched in 1989 and 1990. The duration of the Galileo mission is expected to be over 8 years. This brings the total RTG lifetime to 13 years. In 13 years, the RTG power drops more than 20 percent leaving a very small power margin over what is consumed by the spacecraft. Thus it is very important to accurately predict the RTG performance and be able to assess the magnitude of errors involved. The paper lists all the error sources involved in the RTG power predictions and describes a statistical method for calculating the tolerance

  17. Identification of voltage stability condition of a power system using measurements of bus variables

    Directory of Open Access Journals (Sweden)

    Durlav Hazarika

    2014-12-01

    Full Text Available Several online methods were proposed for investigating the voltage stability condition of an interconnected power system using the measurements of voltage and current phasors at a bus. For this purpose, phasor measurement units (PMUs are used. A PMU is a device which measures the electrical waves on an electrical network, using a common time source (reference bus for synchronisation. This study proposes a method for online monitoring of voltage stability condition of a power system using measurements of bus variables namely – (i real power, (ii reactive power and (iii bus voltage magnitude at a bus. The measurements of real power, reactive power and bus voltage magnitude could be extracted/captured from a smart energy meter. The financial involvement for implementation of the proposed method would significantly lower compared with the PMU-based method.

  18. Bus Implementation Using New Low Power PFSCL Tristate Buffers

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2016-01-01

    Full Text Available This paper proposes new positive feedback source coupled logic (PFSCL tristate buffers suited to bus applications. The proposed buffers use switch to attain high impedance state and modify the load or the current source section. An interesting consequence of this is overall reduction in the power consumption. The proposed tristate buffers consume half the power compared to the available switch based counterpart. The issues with available PFSCL tristate buffers based bus implementation are identified and benefits of employing the proposed tristate buffer topologies are put forward. SPICE simulation results using TSMC 180 nm CMOS technology parameters are included to support the theoretical formulations. The performance of proposed tristate buffer topologies is examined on the basis of propagation delay, output enable time, and power consumption. It is found that one of the proposed tristate buffer topology outperforms the others in terms of all the performance parameters. An examination of behavior of available and the proposed PFSCL tristate buffer topologies under parameter variations and mismatch shows a maximum variation of 14%.

  19. Solar Power System Options for the Radiation and Technology Demonstration Spacecraft

    Science.gov (United States)

    Kerslake, Thomas W.; Haraburda, Francis M.; Riehl, John P.

    2000-01-01

    The Radiation and Technology Demonstration (RTD) Mission has the primary objective of demonstrating high-power (10 kilowatts) electric thruster technologies in Earth orbit. This paper discusses the conceptual design of the RTD spacecraft photovoltaic (PV) power system and mission performance analyses. These power system studies assessed multiple options for PV arrays, battery technologies and bus voltage levels. To quantify performance attributes of these power system options, a dedicated Fortran code was developed to predict power system performance and estimate system mass. The low-thrust mission trajectory was analyzed and important Earth orbital environments were modeled. Baseline power system design options are recommended on the basis of performance, mass and risk/complexity. Important findings from parametric studies are discussed and the resulting impacts to the spacecraft design and cost.

  20. Galileo spacecraft power management and distribution system

    International Nuclear Information System (INIS)

    Detwiler, R.C.; Smith, R.L.

    1990-01-01

    It has been twelve years since two Voyager spacecraft began the direct route to the outer planets. In October 1989 a single Galileo spacecraft started the return to Jupiter. Conceived as a simple Voyager look-alike, the Galileo power management and distribution (PMAD) system has undergone many iterations in configuration. Major changes to the PMAD resulted from dual spun slip ring limitations, variations in launch vehicle thrust capabilities, and launch delays. Lack of an adequate launch vehicle for an interplanetary mission of Galileo's size has resulted in an extremely long flight duration. A Venus-Earth-Earth Gravity Assist (VEEGA) tour, vital to attain the required energy, results in a 6 year trip to Jupiter and its moons. This paper provides a description of the Galileo PMAD and documents the design drivers that established the final as-built hardware

  1. Space power systems--''Spacecraft 2000''

    International Nuclear Information System (INIS)

    Faymon, K.A.

    1985-01-01

    The National Space programs of the 21st century will require abundant and relatively low cost power and energy produced by high reliability-low mass systems. Advancement of current power system related technologies will enable the U.S. to realize increased scientific payload for government missions or increased revenue producing payload for commercial space endeavors. Autonomous, unattended operation will be a highly desirable characteristic of these advanced power systems. Those space power-energy related technologies, which will comprise the space craft of the late 1990's and the early 2000's, will evolve from today's state-of-the-art systems and those long term technology development programs presently in place. However, to foster accelerated development of the more critical technologies which have the potential for high-payoffs, additional programs will be proposed and put in place between now and the end of the century. Such a program is ''Spacecraft 2000'', which is described in this paper

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

    Directory of Open Access Journals (Sweden)

    Baolian Liu

    2014-01-01

    Full Text Available The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the above problem, and the design method is given. The simulation and experiment results proved that the proposed variable structure control algorithm can eliminate the chattering problem existing in traditional variable structure control effectively, is insensitive to system disturbance, and has good robustness and fast dynamic response speed and stable DC bus voltage with small fluctuation. The above advantages ensure the compensation effect of APF.

  3. A Study of BUS Architecture Design for Controller of Nuclear Power Plant Using FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongil; Yun, Donghwa; Hwang, Sungjae; Kim, Myeongyun; Lee, Dongyun [PONUTech Co. Ltd., Seoul (Korea, Republic of)

    2014-05-15

    CPU (Central Processing Unit) operating speed and communication rate have been more technically improved than before. However, whole system is been a degradation of performance by electronic and structural limitation of parallel bus. Transmission quantity and speed have a limit and need arbiter in order to do arbitration because several boards shared parallel bus. Arbiter is a high complexity in implementing so it increases component per chip. If a parallel bus uses, it will occurs some problems what are reflection noise, power/ground noise (or ground bounce) as SSN (Simultaneous Switching Noise) and crosstalk noise like magnetic coupling. In this paper, in order to solve a problem of parallel bus in controller of NPP (Nuclear Power Plant), proposes the bus architecture design using FPGA (Field Programmable Gate Array) based on LVDS (Low Voltage Differential Signaling)

  4. A Study of BUS Architecture Design for Controller of Nuclear Power Plant Using FPGA

    International Nuclear Information System (INIS)

    Lee, Dongil; Yun, Donghwa; Hwang, Sungjae; Kim, Myeongyun; Lee, Dongyun

    2014-01-01

    CPU (Central Processing Unit) operating speed and communication rate have been more technically improved than before. However, whole system is been a degradation of performance by electronic and structural limitation of parallel bus. Transmission quantity and speed have a limit and need arbiter in order to do arbitration because several boards shared parallel bus. Arbiter is a high complexity in implementing so it increases component per chip. If a parallel bus uses, it will occurs some problems what are reflection noise, power/ground noise (or ground bounce) as SSN (Simultaneous Switching Noise) and crosstalk noise like magnetic coupling. In this paper, in order to solve a problem of parallel bus in controller of NPP (Nuclear Power Plant), proposes the bus architecture design using FPGA (Field Programmable Gate Array) based on LVDS (Low Voltage Differential Signaling)

  5. An interconnecting bus power optimization method combining interconnect wire spacing with wire ordering

    International Nuclear Information System (INIS)

    Zhu Zhang-Ming; Hao Bao-Tian; En Yun-Fei; Yang Yin-Tang; Li Yue-Jin

    2011-01-01

    On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency, therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements. The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a global bus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided design of nanometer scale on-chip buses. (interdisciplinary physics and related areas of science and technology)

  6. Diagnosing Faults in Electrical Power Systems of Spacecraft and Aircraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrical power systems play a critical role in spacecraft and aircraft, and they exhibit a rich variety of failure modes. This paper discusses electrical power...

  7. Bus-oriented digital control techniques in nuclear power plants

    International Nuclear Information System (INIS)

    Salm, M.

    1987-01-01

    The author states the conservative principles which govern the authorization procedures for nuclear reactor control systems. Using the example of a feedwater supply regulator, employing a digital, bus-oriented control system, he describes how the stigma attached to the word nuclear can be alleviated. (G.T.H.)

  8. Research on intelligent power distribution system for spacecraft

    Science.gov (United States)

    Xia, Xiaodong; Wu, Jianju

    2017-10-01

    The power distribution system (PDS) mainly realizes the power distribution and management of the electrical load of the whole spacecraft, which is directly related to the success or failure of the mission, and hence is an important part of the spacecraft. In order to improve the reliability and intelligent degree of the PDS, and considering the function and composition of spacecraft power distribution system, this paper systematically expounds the design principle and method of the intelligent power distribution system based on SSPC, and provides the analysis and verification of the test data additionally.

  9. Bus Participation Factor Analysis for Harmonic Instability in Power Electronics Based Power Systems

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2018-01-01

    Compared with the conventional power systems, large-scale power electronics based power systems present a more complex situation, where harmonic instability may be induced by the mutual interactions between the inner control loops of the converters. This paper presents an approach to locate which...... power converters and buses are more sensitive and have significant contribution to the harmonic instability. In the approach, a power electronics based system is introduced as a Multi-Input Multi-Output (MIMO) dynamic system by means of a dynamic admittance matrix. Bus Participation Factors (PFs......) are calculated by the oscillatory mode sensitivity analysis versus the elements of the MIMO transfer function matrix. The PF analysis detects which power electronic converters or buses have a higher participation in harmonic instability excitation than others or at which buses such instability problems have...

  10. Conceptual definition of Automated Power Systems Management. [for planetary spacecraft

    Science.gov (United States)

    Imamura, M. S.; Skelly, L.; Weiner, H.

    1977-01-01

    Automated Power Systems Management (APSM) is defined as the capability of a spacecraft power system to automatically perform monitoring, computational, command, and control functions without ground intervention. Power systems for future planetary spacecraft must have this capability because they must perform up to 10 years, and accommodate real-time changes in mission execution autonomously. Specific APSM functions include fault detection, isolation, and correction; system performance and load profile prediction; power system optimization; system checkout; and data storage and transmission control. This paper describes the basic method of implementing these specific functions. The APSM hardware includes a central power system computer and a processor dedicated to each major power system subassembly along with digital interface circuitry. The major payoffs anticipated are in enhancement of spacecraft reliability and life and reduction of overall spacecraft program cost.

  11. Low power arcjet system spacecraft impacts

    Science.gov (United States)

    Pencil, Eric J.; Sarmiento, Charles J.; Lichtin, D. A.; Palchefsky, J. W.; Bogorad, A. L.

    1993-01-01

    Potential plume contamination of spacecraft surfaces was investigated by positioning spacecraft material samples relative to an arcjet thruster. Samples in the simulated solar array region were exposed to the cold gas arcjet plume for 40 hrs to address concerns about contamination by backstreaming diffusion pump oil. Except for one sample, no significant changes were measured in absorptance and emittance within experimental error. Concerns about surface property degradation due to electrostatic discharges led to the investigation of the discharge phenomenon of charged samples during arcjet ignition. Short duration exposure of charged samples demonstrated that potential differences are consistently and completely eliminated within the first second of exposure to a weakly ionized plume. The spark discharge mechanism was not the discharge phenomenon. The results suggest that the arcjet could act as a charge control device on spacecraft.

  12. Multi-kilowatt modularized spacecraft power processing system development

    International Nuclear Information System (INIS)

    Andrews, R.E.; Hayden, J.H.; Hedges, R.T.; Rehmann, D.W.

    1975-07-01

    A review of existing information pertaining to spacecraft power processing systems and equipment was accomplished with a view towards applicability to the modularization of multi-kilowatt power processors. Power requirements for future spacecraft were determined from the NASA mission model-shuttle systems payload data study which provided the limits for modular power equipment capabilities. Three power processing systems were compared to evaluation criteria to select the system best suited for modularity. The shunt regulated direct energy transfer system was selected by this analysis for a conceptual design effort which produced equipment specifications, schematics, envelope drawings, and power module configurations

  13. The electrical power subsystem design for the high energy solar physics spacecraft concepts

    Science.gov (United States)

    Kulkarni, Milind

    1993-01-01

    This paper discusses the Electrical Power Subsystem (EPS) requirements, architecture, design description, performance analysis, and heritage of the components for two spacecraft concepts for the High Energy Solar Physics (HESP) Mission. It summarizes the mission requirements and the spacecraft subsystems and instrument power requirements, and it describes the EPS architecture for both options. A trade study performed on the selection of the solar cells - body mounted versus deployed panels - and the optimum number of panels is also presented. Solar cell manufacturing losses, array manufacturing losses, and the radiation and temperature effects on the GaAs/Ge and Si solar cells were considered part of the trade study and are included in this paper. Solar cell characteristics, cell circuit description, and the solar array area design are presented, as is battery sizing analysis performed based on the power requirements during launch and initial spacecraft operations. This paper discusses Earth occultation periods and the battery power requirements during this period as well as shunt control, battery conditioning, and bus regulation schemes. Design margins, redundancy philosophy, and predicted on-orbit battery and solar cell performance are summarized. Finally, the heritage of the components and technology risk assessment are provided.

  14. Large autonomous spacecraft electrical power system (LASEPS)

    Science.gov (United States)

    Dugal-Whitehead, Norma R.; Johnson, Yvette B.

    1992-01-01

    NASA - Marshall Space Flight Center is creating a large high voltage electrical power system testbed called LASEPS. This testbed is being developed to simulate an end-to-end power system from power generation and source to loads. When the system is completed it will have several power configurations, which will include several battery configurations. These configurations are: two 120 V batteries, one or two 150 V batteries, and one 250 to 270 V battery. This breadboard encompasses varying levels of autonomy from remote power converters to conventional software control to expert system control of the power system elements. In this paper, the construction and provisions of this breadboard are discussed.

  15. Reactive Power Control in Eight Bus System Using FC-TCR

    Directory of Open Access Journals (Sweden)

    Thangavelu Vijayakumar

    2010-02-01

    Full Text Available This paper deals with the simulation of eight bus system having fixed capacitor and thyristor controlled reactor. The system is modeled and simulated using MATLAB.The simulation results are presented. The power and control circuits are simulated. The current drawn by the TCR varies with the variation in the firing angle. The simulation results are compared with the theoretical results.

  16. Nuclear-Powered GPS Spacecraft Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Bernard

    1977-05-01

    This is the final report of a study to investigate the potential benefits of a nuclear (radioisotope) - powered satellite for advanced phases of the Global Positioning System (GPS) program. The critical parameters were: power to user; mean mission duration; orbital predictability; thermal control of on-board frequency standards; and vulnerability. The reference design approach is described, and input data are given for two power systems that are under development: an organic Rankine system and a Brayton cycle system. Reference design details are provided and structural design and analysis are discussed, as well as thermal design and analysis. A higher altitude version is also considered.

  17. Generic 12-Bus Test System for Wind Power Integration Studies

    DEFF Research Database (Denmark)

    Adamczyk, Andrzej Grzegorz; Altin, Müfit; Göksu, Ömer

    2012-01-01

    , inertial response, frequency control, damping of electromechanical oscillations, balanced and unbalanced fault management, etc. Hence, the power system components: conventional power plants with controls, transmission lines, transformers and loads should be represented accurately to achieve realistic power......High wind power penetration levels into power systems requires an appropriate power system model when assessing impact on the overall system stability. The model should capture the wide range of dynamics related to the wind integration studies, such as voltage control, synchronizing power control...... system characteristics. Additionally, the power system model should be simple and computationally manageable in order to simulate multiple scenarios with different control parameters in a reasonable time. In this paper, a generic power system model is presented in order to comprehend the wind integration...

  18. Nuclear-powered Hysat spacecraft: comparative design study

    International Nuclear Information System (INIS)

    Raab, B.

    1975-08-01

    The study shows that the all-nuclear spacecraft can have a substantial weight advantage over a hybrid (nuclear/solar) or all-solar spacecraft, owing to a further reduction in power requirement, and to the elimination of such equipment as the sensor gimbal and rotating joint assemblies. Because the need for a sun-oriented section is eliminated, the all-nuclear spacecraft can be designed as a monolithic structure, with the sensor and other payload firmly secured in a fixed position on the structure. This enhances attitude stability while minimizing structural weight and eliminating the need for flexible fluid lines. Sensor motion can be produced, varied, and controlled within the limits specified by the study contractors by moving the entire spacecraft in the prescribed pattern. A simple attitude control system using available hardware suffices to meet all requirements

  19. Transient Stability Improvement of IEEE 9 Bus System Using Power World Simulator

    Directory of Open Access Journals (Sweden)

    Kaur Ramandeep

    2016-01-01

    Full Text Available The improvement of transient stability of power system was one of the most challenging research areas in power engineer.The main aim of this paper was transient stability analysis and improvement of IEEE 9 bus system. These studies were computed using POWER WORLD SIMULATOR. The IEEE 9 bus system was modelled in power world simulator and load flow studies were performed to determine pre-fault conditions in the system using Newton-Raphson method. The transient stability analysis was carried out using Runga method during three-phase balanced fault. For the improvement transient stability, the general methods adopted were fast acting exciters, FACT devices and addition of parallel transmission line. These techniques play an important role in improving the transient stability, increasing transmission capacity and damping low frequency oscillations.

  20. Power-balancing instantaneous optimization energy management for a novel series-parallel hybrid electric bus

    Science.gov (United States)

    Sun, Dongye; Lin, Xinyou; Qin, Datong; Deng, Tao

    2012-11-01

    Energy management(EM) is a core technique of hybrid electric bus(HEB) in order to advance fuel economy performance optimization and is unique for the corresponding configuration. There are existing algorithms of control strategy seldom take battery power management into account with international combustion engine power management. In this paper, a type of power-balancing instantaneous optimization(PBIO) energy management control strategy is proposed for a novel series-parallel hybrid electric bus. According to the characteristic of the novel series-parallel architecture, the switching boundary condition between series and parallel mode as well as the control rules of the power-balancing strategy are developed. The equivalent fuel model of battery is implemented and combined with the fuel of engine to constitute the objective function which is to minimize the fuel consumption at each sampled time and to coordinate the power distribution in real-time between the engine and battery. To validate the proposed strategy effective and reasonable, a forward model is built based on Matlab/Simulink for the simulation and the dSPACE autobox is applied to act as a controller for hardware in-the-loop integrated with bench test. Both the results of simulation and hardware-in-the-loop demonstrate that the proposed strategy not only enable to sustain the battery SOC within its operational range and keep the engine operation point locating the peak efficiency region, but also the fuel economy of series-parallel hybrid electric bus(SPHEB) dramatically advanced up to 30.73% via comparing with the prototype bus and a similar improvement for PBIO strategy relative to rule-based strategy, the reduction of fuel consumption is up to 12.38%. The proposed research ensures the algorithm of PBIO is real-time applicability, improves the efficiency of SPHEB system, as well as suite to complicated configuration perfectly.

  1. Power flow control strategy in distribution network for dc type distributed energy resource at load bus

    International Nuclear Information System (INIS)

    Hanif, A.; Choudhry, M.A.

    2013-01-01

    This research work presents a feed forward power flow control strategy in the secondary distribution network working in parallel with a DC type distributed energy resource (DER) unit with SPWM-IGBT Voltage Source Converter (VSC). The developed control strategy enables the VSC to be used as power flow controller at the load bus in the presence of utility supply. Due to the investigated control strategy, power flow control from distributed energy resource (DER) to common load bus is such that power flows to the load without facing any power quality problem. The technique has an added advantage of controlling power flow without having a dedicated power flow controller. The SPWM-IGBT VSC is serving the purpose of dc-ac converter as well as power flow controller. Simulations for a test system using proposed power flow control strategy are carried out using SimPower Systems toolbox of MATLAB at the rate and Simulink at the rate. The results show that a reliable, effective and efficient operation of DC type DER unit in coordination with main utility network can be achieved. (author)

  2. Electrical engineering unit for the reactive power control of the load bus at the voltage instability

    Science.gov (United States)

    Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

    2018-01-01

    For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

  3. Optimization of a PEMFC/battery pack power system for a bus application

    International Nuclear Information System (INIS)

    Barelli, Linda; Bidini, Gianni; Ottaviano, Andrea

    2012-01-01

    Highlights: ► A dynamic model of a PEMFC/battery system for bus traction has been developed. ► The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. ► The system output power have been determined according to the real driving load demand of a bus during 12 h. ► The model has allowed the sizing of the fuel cell and the hydrogen tank with the SOC control strategy optimization. ► The PEMFC power that allows to optimize the operation in terms of both SOC control strategy and consumption is 33 kW e . -- Abstract: In a global environment context in which the urgent need to reduce pollutant emissions is of central relevance, it is becoming increasingly important the research for solutions, concerning the vehicular transport sector with low environmental impact. Fuel cell technology is expected to become a viable solution for these applications due to its environmental friendly characteristics. The present study concerns the traction system of a bus considering the case of hybrid solutions consisting of a proton exchange membrane fuel cell (PEMFC) in parallel with a battery pack. In particular, a dynamic model of a PEMFC/battery system is presented for the application under study. The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. The fuel cell and the battery output power have been determined according to the real driving load demand of a bus taking into consideration a daily operation of 12 h. Such a model has allowed the correct dimensioning of the hybrid power system (giving a particular attention to the fuel cell and the hydrogen tank) together with the optimization of the SOC control strategy.

  4. Causes and effects of vital instrumentation and control power supply bus failures

    International Nuclear Information System (INIS)

    Muhlheim, M.D.; Murphy, G.A.

    1987-01-01

    This article presents the results of a study in which the objective was to evaluate nuclear power-plant operating experience to identify the causes and the effects of vital instrumentation and control (I and C) power supply bus failures. Vital I and C power is normally provided to essential instrumentation and controls through either vital d-c or a-c power supply systems. The vital d-c power supply system generally provides control power for starting the diesel generators, for operating electrical circuit breakers, and for controlling various logic circuits. The vital d-c power system also supplies vital a-c power through an inverter. The vital a-c power supply system generally feeds the reactor protection system channels, the engineered safety features actuation system channels, and critical instrumentation in the control room. The leading cause of vital bus failures is inverter failures; other causes are human errors, battery charger failures, and miscellaneous failures. The effects of these failures are that the margin of safety can be degraded by (1) denying key information to the operators, (2) inducing plant transients, (3) causing safety injection actuations, and (4) causing the loss of shutdown cooling flow

  5. Power quality load management for large spacecraft electrical power systems

    Science.gov (United States)

    Lollar, Louis F.

    1988-01-01

    In December, 1986, a Center Director's Discretionary Fund (CDDF) proposal was granted to study power system control techniques in large space electrical power systems. Presented are the accomplishments in the area of power system control by power quality load management. In addition, information concerning the distortion problems in a 20 kHz ac power system is presented.

  6. Multi-Output Power Converter, Operated from a Regulated Input Bus, for the Sireus Rate Sensor

    Directory of Open Access Journals (Sweden)

    Torrecilla Marcos Compadre

    2017-01-01

    Full Text Available This paper describes a DC to DC converter designed to meet the power supply requirements of the SiREUS Coarse Rate Sensor (CRS which is a 3-axis MEMS Rate Sensor (MRS that uses a resonating ring gyro and will be used in different ESA missions. The converter supplies +5V, −5V, 3.3V, 1.8V and 40V and it has been designed and prototyped by Clyde Space Ltd with the EQM and FM units being manufactured by Selex ES. The first model was designed for a 28V un-regulated bus and the second model presented here has been designed for a 50V regulated bus. PWM voltage regulation was not used because of the noise requirements and the regulated input bus allowed an unregulated power stage approach. There are also stringent volume and interface constraints, which also affected the design. For such reasons, a fixed dutycycle, quasi-resonant single-ended topology with output linear regulators has been implemented; having the advantages of providing low switching losses, low radiated and conducted noise and no over-voltage failure mode. This paper highlights the techniques used to satisfy stringent noise and protection requirements of the load.

  7. Tohyco-Rider: hybrid bus with super-caps and inductive power transfer

    Energy Technology Data Exchange (ETDEWEB)

    Harri, V.; Carriero, D. [HTA Luzern, Horw (Switzerland)

    2004-07-01

    The TOHYCO-Rider-Bus was developed during a Swiss research project at HTA Lucerne (University of Applied Sciences of Central Switzerland). Each time, the bus only picks up enough energy to safely reach the next charging station. Instead of common re-chargeable batteries, the TOHYCO-Rider uses electrical high-power capacitors, so-called super-capacitors, as energy storage. In combination with an absolutely non-dangerous, non-contact, inductive energy re-charging system the S-CAPs can be reloaded with a higher efficiency and much more quickly than batteries. Within 3-5 minutes of charging time the vehicle is prepared for its next trip. A further advantage of this concept is that, with the S-CAPs, only the energy supply has to be taken along for the next stop (approx. 300 kg) and not a charge of batteries for the entire day (approx. 2t). Because of the lighter weight, the TOHYCO-Rider is therefore an economically and ecologically interesting mean of transportation. In summer 2004 the TOHYCO-Rider ran in a pilot operation. During three months the mini-bus drove in a time-scheduled operation in the city of Lucerne, with the aim of proving the reliability and fitness of the developed system in daily operation. The test operation was terminated recently and the results were very promising. (authors)

  8. Automating a spacecraft electrical power system using expert systems

    Science.gov (United States)

    Lollar, L. F.

    1991-01-01

    Since Skylab, Marshall Space Flight Center (MSFC) has recognized the need for large electrical power systems (EPS's) in upcoming Spacecraft. The operation of the spacecraft depends on the EPS. Therefore, it must be efficient, safe, and reliable. In 1978, as a consequence of having to supply a large number of EPS personnel to monitor and control Skylab, the Electrical power Branch of MSFC began the autonomously managed power system (AMPS) project. This project resulted in the assembly of a 25-kW high-voltage dc test facility and provided the means of getting man out of the loop as much as possible. AMPS includes several embedded controllers which allow a significant level of autonomous operation. More recently, the Electrical Division at MSFC has developed the space station module power management and distribution (SSM/PMAD) breadboard to investigate managing and distributing power in the Space Station Freedom habitation and laboratory modules. Again, the requirement for a high level of autonomy for the efficient operation over the lifetime of the station and for the benefits of enhanced safety has been demonstrated. This paper describes the two breadboards and the hierarchical approach to automation which was developed through these projects.

  9. Study of reactor Brayton power systems for nuclear electric spacecraft

    Science.gov (United States)

    1979-01-01

    The feasibility of using Brayton power systems for nuclear electric spacecraft was investigated. The primary performance parameters of systems mass and radiator area were determined for systems from 100 to 1000 kW sub e. Mathematical models of all system components were used to determine masses and volumes. Two completely independent systems provide propulsion power so that no single-point failure can jeopardize a mission. The waste heat radiators utilize armored heat pipes to limit meteorite puncture. The armor thickness was statistically determined to achieve the required probability of survival. A 400 kW sub e reference system received primary attention as required by the contract. The components of this system were defined and a conceptual layout was developed with encouraging results. An arrangement with redundant Brayton power systems having a 1500 K (2240 F) turbine inlet temperature was shown to be compatible with the dimensions of the space shuttle orbiter payload bay.

  10. Flight Plasma Diagnostics for High-Power, Solar-Electric Deep-Space Spacecraft

    Science.gov (United States)

    Johnson, Lee; De Soria-Santacruz Pich, Maria; Conroy, David; Lobbia, Robert; Huang, Wensheng; Choi, Maria; Sekerak, Michael J.

    2018-01-01

    NASA's Asteroid Redirect Robotic Mission (ARRM) project plans included a set of plasma and space environment instruments, the Plasma Diagnostic Package (PDP), to fulfill ARRM requirements for technology extensibility to future missions. The PDP objectives were divided into the classes of 1) Plasma thruster dynamics, 2) Solar array-specific environmental effects, 3) Plasma environmental spacecraft effects, and 4) Energetic particle spacecraft environment. A reference design approach and interface requirements for ARRM's PDP was generated by the PDP team at JPL and GRC. The reference design consisted of redundant single-string avionics located on the ARRM spacecraft bus as well as solar array, driving and processing signals from multiple copies of several types of plasma, effects, and environments sensors distributed over the spacecraft and array. The reference design sensor types were derived in part from sensors previously developed for USAF Research Laboratory (AFRL) plasma effects campaigns such as those aboard TacSat-2 in 2007 and AEHF-2 in 2012.

  11. Reactor/Brayton power systems for nuclear electric spacecraft

    Science.gov (United States)

    Layton, J. P.

    1980-01-01

    Studies are currently underway to assess the technological feasibility of a nuclear-reactor-powered spacecraft propelled by electric thrusters. This vehicle would be capable of performing detailed exploration of the outer planets of the solar system during the remainder of this century. The purpose of this study was to provide comparative information on a closed cycle gas turbine power conversion system. The results have shown that the performance is very competitive and that a 400 kWe space power system is dimensionally compatible with a single Space Shuttle launch. Performance parameters of system mass and radiator area were determined for systems from 100 to 1000 kWe. A 400 kWe reference system received primary attention. The components of this system were defined and a conceptual layout was developed with encouraging results. The preliminary mass determination for the complete power system was very close to the desired goal of 20 kg/kWe. Use of more advanced technology (higher turbine inlet temperature) will substantially improve system performance characteristics.

  12. Radioisotope AMTEC power system designs for spacecraft applications

    International Nuclear Information System (INIS)

    Ivanenok, J.F. III; Sievers, R.K.; Hunt, T.K.; Johnson, G.A.

    1993-01-01

    The Alkali Metal Thermal to Electric Converter (AMTEC) system is an exceptional candidate for high performance spacecraft power systems including small systems powered by General Purpose Heat Sources (GPHS). The AMTEC converter is best described as a thermally regenerative electrochemical concentration cell. AMTEC is a static energy conversion device and can operate at efficiencies between 15% and 30%. The single tube, remote condensed, wick return minicell design has been incorporated into a radioisotope powered system model. Reported cell efficiencies used for these system design studies ranged from 15% to 25%. This efficiency is significantly higher than other static conversion systems operating at the same temperatures. Savings in mass and cost, relative to other more conventional static conversion systems, have also been shown. The minicell used for this system study has many advanced features not combined in previous designs, including wick return, remote condensing, and hot zone feedthroughs. All of these features significantly enhance the performance of the AMTEC cell. Additionally, the cell end provides enough area for adequate heat transfer from the GPHS module, eliminating the need for a ''hot shoe'', and reducing the complexity and weight of the system. This paper describes and compares small (two module) and larger (16 module) AMTEC radioisotope powered systems and describes the computer model developed to predict their performance

  13. Longevity-conscious dimensioning and power management of the hybrid energy storage system in a fuel cell hybrid electric bus

    International Nuclear Information System (INIS)

    Hu, Xiaosong; Johannesson, Lars; Murgovski, Nikolce; Egardt, Bo

    2015-01-01

    Highlights: • Hybrid energy storage system is optimally sized and controlled for a hybrid bus. • Dynamic battery health model is incorporated in the optimization. • Convex programming is efficient for optimizing hybrid propulsion systems. • Optimal battery replacement strategy is explored. • Comparison to the battery-only option is made in the health-aware optimization. - Abstract: Energy storage systems (ESSs) play an important role in the performance and economy of electrified vehicles. Hybrid energy storage system (HESS) combining both lithium-ion cells and supercapacitors is one of the most promising solutions. This paper discusses the optimal HESS dimensioning and energy management of a fuel cell hybrid electric bus. Three novel contributions are added to the relevant literature. First, efficient convex programming is used to simultaneously optimize the HESS dimension (including sizes of both the lithium-ion battery pack and the supercapacitor stack) and the power allocation between the HESS and the fuel cell system (FCS) of the hybrid bus. In the combined plant/controller optimization problem, a dynamic battery State-of-Health (SOH) model is integrated to quantitatively examine the impact of the battery replacement strategy on both the HESS size and the bus economy. Second, the HESS and the battery-only ESS options are systematically compared in the proposed optimization framework. Finally, the battery-health-perceptive HESS optimization outcome is contrasted to the ideal one neglecting the battery degradation (assuming that the battery is durable over the bus service period without deliberate power regulation)

  14. Distributed photovoltaic architecture powering a DC bus: Impact of duty cycle and load variations on the efficiency of the generator

    Science.gov (United States)

    Allouache, Hadj; Zegaoui, Abdallah; Boutoubat, Mohamed; Bokhtache, Aicha Aissa; Kessaissia, Fatma Zohra; Charles, Jean-Pierre; Aillerie, Michel

    2018-05-01

    This paper focuses on a photovoltaic generator feeding a load via a boost converter in a distributed PV architecture. The principal target is the evaluation of the efficiency of a distributed photovoltaic architecture powering a direct current (DC) PV bus. This task is achieved by outlining an original way for tracking the Maximum Power Point (MPP) taking into account load variations and duty cycle on the electrical quantities of the boost converter and on the PV generator output apparent impedance. Thereafter, in a given sized PV system, we analyze the influence of the load variations on the behavior of the boost converter and we deduce the limits imposed by the load on the DC PV bus. The simultaneous influences of 1- the variation of the duty cycle of the boost converter and 2- the load power on the parameters of the various components of the photovoltaic chain and on the boost performances are clearly presented as deduced by simulation.

  15. Designing fault-tolerant real-time computer systems with diversified bus architecture for nuclear power plants

    International Nuclear Information System (INIS)

    Behera, Rajendra Prasad; Murali, N.; Satya Murty, S.A.V.

    2014-01-01

    Fault-tolerant real-time computer (FT-RTC) systems are widely used to perform safe operation of nuclear power plants (NPP) and safe shutdown in the event of any untoward situation. Design requirements for such systems need high reliability, availability, computational ability for measurement via sensors, control action via actuators, data communication and human interface via keyboard or display. All these attributes of FT-RTC systems are required to be implemented using best known methods such as redundant system design using diversified bus architecture to avoid common cause failure, fail-safe design to avoid unsafe failure and diagnostic features to validate system operation. In this context, the system designer must select efficient as well as highly reliable diversified bus architecture in order to realize fault-tolerant system design. This paper presents a comparative study between CompactPCI bus and Versa Module Eurocard (VME) bus architecture for designing FT-RTC systems with switch over logic system (SOLS) for NPP. (author)

  16. Design of a fiber optic multi-tapped computer bus for a pulsed power control system application

    International Nuclear Information System (INIS)

    Gritton, D.G.; Berkbigler, L.W.; Oicles, J.A.

    1979-01-01

    Control system techniques developed and proven on the Shiva laser have been extended to incorporate new electronic and electo-optic devices as well as conform to unique operational requirements of the 300 terawatt Nova laser system. This paper describes one segment of the control system being designed for the Nova laser currently under design/construction at Lawrence Livermore Laboratory. The specific segment covered is the control system bus structure responsible for power conditioning and real-time control functions

  17. Multiple output power supply circuit for an ion engine with shared upper inverter

    Science.gov (United States)

    Cardwell, Jr., Gilbert I. (Inventor); Phelps, Thomas K. (Inventor)

    2001-01-01

    A power supply circuit for an ion engine suitable for a spacecraft is coupled to a bus having a bus input and a bus return. The power supply circuit has a first primary winding of a first transformer. An upper inverter circuit is coupled to the bus input and the first primary winding. The power supply circuit further includes a first lower inverter circuit coupled to the bus return and the first primary winding. The second primary winding of a second transformer is coupled to the upper inverter circuit. A second lower inverter circuit is coupled to the bus return and the second primary winding.

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

    Directory of Open Access Journals (Sweden)

    Robert Antonio Salas-Puente

    2018-03-01

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

  19. Electrical system architecture having high voltage bus

    Science.gov (United States)

    Hoff, Brian Douglas [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL

    2011-03-22

    An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

  20. DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (UNIX VERSION)

    Science.gov (United States)

    Jagielski, J. M.

    1994-01-01

    The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

  1. Spacecraft Electrical Power System (EPS) generic analysis tools and techniques

    Science.gov (United States)

    Morris, Gladys M.; Sheppard, Mark A.

    1992-01-01

    An overview is provided of the analysis tools and techiques used in modeling the Space Station Freedom electrical power system, as well as future space vehicle power systems. The analysis capabilities of the Electrical Power System (EPS) are described and the EPS analysis tools are surveyed.

  2. Scaling Laws in Chennai Bus Network

    OpenAIRE

    Chatterjee, Atanu; Ramadurai, Gitakrishnan

    2015-01-01

    In this paper, we study the structural properties of the complex bus network of Chennai. We formulate this extensive network structure by identifying each bus stop as a node, and a bus which stops at any two adjacent bus stops as an edge connecting the nodes. Rigorous statistical analysis of this data shows that the Chennai bus network displays small-world properties and a scale-free degree distribution with the power-law exponent, $\\gamma > 3$.

  3. SPFC bus design studies

    Energy Technology Data Exchange (ETDEWEB)

    Potter, L.; Reinkingh, J.

    1999-07-01

    This report presents the results of a study assessing the design options for a solid polymer fuel cell bus. Commercial and operation requirements, environmental and market drivers, and fuel processor modeling are examined. Power train specifications and detailed system design are investigated covering fuel cell system dynamic response, hybrid system size, fuel cell system start-up time, system specifications, and hybrid bus component dimensions and costs. (UK)

  4. Development and Analysis of a Resource-Aware Power Management System as Applied to Small Spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Shriver, Patrick [Univ. of Colorado, Boulder, CO (United States)

    2005-01-01

    In this thesis, an overall framework and solution method for managing the limited power resources of a small spacecraft is presented. Analogous to mobile computing technology, a primary limiting factor is the available power resources. In spite of the millions of dollars budgeted for research and development over decades, improvements in battery efficiency remains low. This situation is exacerbated by advances in payload technology that lead to increasingly power-hungry and data-intensive instruments. The challenge for the small spacecraft is to maximize capabilities and performance while meeting difficult design requirements and small project budgets.

  5. Spacecraft electrical power subsystem: Failure behavior, reliability, and multi-state failure analyses

    International Nuclear Information System (INIS)

    Kim, So Young; Castet, Jean-Francois; Saleh, Joseph H.

    2012-01-01

    This article investigates the degradation and failure behavior of spacecraft electrical power subsystem (EPS) on orbit. First, this work provides updated statistical reliability and multi-state failure analyses of spacecraft EPS and its different constituents, namely the batteries, the power distribution, and the solar arrays. The EPS is shown to suffer from infant mortality and to be a major driver of spacecraft unreliability. Over 25% of all spacecraft failures are the result of EPS failures. As a result, satellite manufacturers may wish to pursue targeted improvement to this subsystem, either through better testing or burn-in procedures, better design or parts selection, or additional redundancy. Second, this work investigates potential differences in the EPS degradation and failure behavior for spacecraft in low earth orbits (LEO) and geosynchronous orbits (GEO). This analysis was motivated by the recognition that the power/load cycles and the space environment are significantly different in LEO and GEO, and as such, they may result in different failure behavior for the EPS in these two types of orbits. The results indicate, and quantify the extent to which, the EPS fails differently in LEO and GEO, both in terms of frequency and severity of failure events. A casual summary of the findings can be stated as follows: the EPS fails less frequently but harder (with fatal consequences to the spacecraft) in LEO than in GEO.

  6. Development of software to improve AC power quality on large spacecraft

    Science.gov (United States)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, alternating current (AC) power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can become a serious problem. It can cause malfunctions in equipment that the power system is supplying, and, during distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. To address the harmonic distortion issue, work was begun under the 1990 NASA-ASEE Summer Faculty Fellowship Program. Software, originally developed by EPRI, called HARMFLO, a power flow program capable of analyzing harmonic conditions on three phase, balanced, 60 Hz AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The modelling was also started under the same fellowship work period. Details of the modifications and models completed during the 1990 NASA-ASEE Summer Faculty Fellowship Program can be found in a project report. As a continuation of the work to develop a complete package necessary for the full analysis of spacecraft AC power system behavior, deployment work has continued through NASA Grant NAG3-1254. This report details the work covered by the above mentioned grant.

  7. Power Replenishment Patch for Spacecraft Health Monitoring Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Metis Design Corporation (MDC) proposes the development of a strain-based power replenishment technology to harvest energy for recharging remote sensors. MDC has...

  8. Small Spacecraft Integrated Power System with Active Thermal Control

    Data.gov (United States)

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

  9. A Compact, Low Power Pulsed Optical Communication System for Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to reduce the power required for high bandwidth, deep space laser communications systems. Our concept will encode data in the time delay...

  10. Application of Autonomous Spacecraft Power Control Technology to Terrestrial Microgrids

    Science.gov (United States)

    Dever, Timothy P.; Trase, Larry M.; Soeder, James F.

    2014-01-01

    This paper describes the potential of the power campus located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio for microgrid development. First, the benefits provided by microgrids to the terrestrial power grid are described, and an overview of Technology Needs for microgrid development is presented. Next, GRC's work on development of autonomous control for manned deep space vehicles, which are essentially islanded microgrids, is covered, and contribution of each of these developments to the microgrid Technology Needs is detailed. Finally, a description is provided of GRC's existing physical assets which can be applied to microgrid technology development, and a phased plan for development of a microgrid test facility is presented.

  11. Design & Development of FPGA Based VME Bus Controller

    OpenAIRE

    Himali Patel; Poornima Talwai

    2015-01-01

    The VME bus interface Controller (VIC068A) is used to interface Local CPU bus and VME bus. VME Bus Controller is used in wide application areas where high reliability, good accuracy and high speed are desired to withstand industrial environment like nuclear power plant and process industries. VME Bus controller can configure as Master, Slave, Interrupt Handler, arbiter as well as power monitor. Commercial VME Bus interface controller chips are available from a few vend...

  12. Adaptation and Re-Use of Spacecraft Power System Models for the Constellation Program

    Science.gov (United States)

    Hojnicki, Jeffrey S.; Kerslake, Thomas W.; Ayres, Mark; Han, Augustina H.; Adamson, Adrian M.

    2008-01-01

    NASA's Constellation Program is embarking on a new era of space exploration, returning to the Moon and beyond. The Constellation architecture will consist of a number of new spacecraft elements, including the Orion crew exploration vehicle, the Altair lunar lander, and the Ares family of launch vehicles. Each of these new spacecraft elements will need an electric power system, and those power systems will need to be designed to fulfill unique mission objectives and to survive the unique environments encountered on a lunar exploration mission. As with any new spacecraft power system development, preliminary design work will rely heavily on analysis to select the proper power technologies, size the power system components, and predict the system performance throughout the required mission profile. Constellation projects have the advantage of leveraging power system modeling developments from other recent programs such as the International Space Station (ISS) and the Mars Exploration Program. These programs have developed mature power system modeling tools, which can be quickly modified to meet the unique needs of Constellation, and thus provide a rapid capability for detailed power system modeling that otherwise would not exist.

  13. Savannah River bus project

    Energy Technology Data Exchange (ETDEWEB)

    Summers, W.A. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1998-08-01

    The H2Fuel Bus is the world`s first hybrid hydrogen electric transit bus. It was developed through a public/private partnership involving several leading technology and industrial organizations in the Southeast, with primary funding and program management provided by the Department of Energy. The primary goals of the project are to gain valuable information on the technical readiness and economic viability of hydrogen buses and to enhance the public awareness and acceptance of emerging hydrogen technologies. The bus has been operated by the transit agency in Augusta, Georgia since April, 1997. It employs a hybrid IC engine/battery/electric drive system, with onboard hydrogen fuel storage based on the use of metal hydrides. Initial operating results have demonstrated an overall energy efficiency (miles per Btu) of twice that of a similar diesel-fueled bus and an operating range twice that of an all-battery powered electric bus. Tailpipe emissions are negligible, with NOx less than 0.2 ppm. Permitting, liability and insurance issues were addressed on the basis of extensive risk assessment and safety analyses, with the inherent safety characteristic of metal hydride storage playing a major role in minimizing these concerns. Future plans for the bus include continued transit operation and use as a national testbed, with potential modifications to demonstrate other hydrogen technologies, including fuel cells.

  14. The Global Precipitation Measurement (GPM) Spacecraft Power System Design and Orbital Performance

    Science.gov (United States)

    Dakermanji, George; Burns, Michael; Lee, Leonine; Lyons, John; Kim, David; Spitzer, Thomas; Kercheval, Bradford

    2016-01-01

    The Global Precipitation Measurement (GPM) spacecraft was jointly developed by National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA). It is a Low Earth Orbit (LEO) spacecraft launched on February 27, 2014. The spacecraft is in a circular 400 Km altitude, 65 degrees inclination nadir pointing orbit with a three year basic mission life. The solar array consists of two sun tracking wings with cable wraps. The panels are populated with triple junction cells of nominal 29.5% efficiency. One axis is canted by 52 degrees to provide power to the spacecraft at high beta angles. The power system is a Direct Energy Transfer (DET) system designed to support 1950 Watts orbit average power. The batteries use SONY 18650HC cells and consist of three 8s x 84p batteries operated in parallel as a single battery. The paper describes the power system design details, its performance to date and the lithium ion battery model that was developed for use in the energy balance analysis and is being used to predict the on-orbit health of the battery.

  15. SSTL based thermal and power efficient RAM design on 28nm FPGA for spacecraft

    DEFF Research Database (Denmark)

    Kalia, Kartik; Pandey, Bishwajeet; Hussain, D. M.A.

    2016-01-01

    In this paper, an approach is made to design a Thermal and Power efficient RAM for that reason we have used DDR4L memory and six different members of SSTL I/Os standards on 28nm technology. Every spacecraft requires most energy efficient electronic system and for that very purpose we have designe...

  16. DC-bus voltage control of grid-connected voltage source converter by using space vector modulated direct power control under unbalanced network conditions

    DEFF Research Database (Denmark)

    Xiao, Lei; Huang, Shoudao; Lu, Kaiyuan

    2013-01-01

    Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load. In this......Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load....... In this study, a new proportional-integral-resonant (PI-RES) controller-based, space vector modulated direct power control topology is proposed to suppress the dc-bus voltage ripple and in the same time, controlling effectively the instantaneous power of the VSC. A special ac reactive power reference component...... is introduced in the controller, which is necessary in order to reduce the dc-bus voltage ripple and active power harmonics at the same time. The proposed control topology is implemented in the lab. Simulation and experimental results are provided to validate its performance and the analysis presented...

  17. Bus fuel consumption model

    Energy Technology Data Exchange (ETDEWEB)

    Zargari, S.A. [Iran Univ. of Science and Technology, Teheran (Iran, Islamic Republic of); Khan, A.M. [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering

    2000-07-01

    The interest in rapid bus transit has increased sharply with the realization that modern metropolitan areas rely on public transit to provide for strong economies and communities. As a prevention tool against traffic congestion, deteriorating air quality and rising greenhouse gas emissions, this study of bus fuel consumption was designed to assist in the planning and management of rapid bus transit. The Australian Road Research Board's (ARRB) Road Fuel Consumption Model was used as a starting point. The estimations required were realized with the help of Newtonian Mechanics. The four states of vehicular traffic were examined: acceleration, cruise, deceleration, and idle. The estimated total power required from the engine to overcome resistance forces, to run vehicle accessories and overcome internal engine friction was calculated. The data for the standard and articulated bus was obtained from OC Transpo in Ottawa. The study permitted the authors to conclude that the estimations for the parameters for power requirements and fuel consumption for heavy duty vehicles are appropriate. The methodology for the estimation of fuel consumption on the Transitway, which is part of the rapid bus transit system, proved adequate. In addition, the methodology was useful to estimate fuel savings resulting from demand management strategies with potential for modal shift. 9 refs., 6 tabs.

  18. Developing a Natural Gas-Powered Bus Rapid Transit Service: A Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, G.

    2015-11-03

    The Roaring Fork Transit Authority (RFTA) and its VelociRFTA Bus Rapid Transit (BRT) program are unique in many ways. For example, VelociRFTA was the first rural BRT system in the United States and the operational environment of the VelociRFTA BRT is one of the most severe in the country, with extreme winter temperatures and altitudes close to 8,000 feet. RFTA viewed high altitude operation as the most challenging characteristic when it began considering the use of natural gas. RFTA is the second-largest public transit system in Colorado behind Denver's Regional Transportation District (RTD), and it is one of the largest rural public transit systems in the country. In 2013, RFTA accepted delivery of 22 new compressed natural gas (CNG) buses that went into service after completion of maintenance and refueling facilities earlier that year. This paper examines the lessons learned from RFTA's experience of investigating--and ultimately choosing--CNG for their new BRT program and focuses on the unique environment of RFTA's BRT application; the decision process to include CNG fueling in the project; unforeseen difficulties encountered in the operation of CNG buses; public perception; cost comparison to competing fuels; and considerations for indoor fueling facilities and project funding.

  19. Developing a Natural Gas-Powered Bus Rapid Transit Service. A Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, George [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-01

    The Roaring Fork Transit Authority (RFTA) and its VelociRFTA Bus Rapid Transit (BRT) program are unique in many ways. For example, VelociRFTA was the first rural BRT system in the United States and the operational environment of the VelociRFTA BRT is one of the most severe in the country, with extreme winter temperatures and altitudes close to 8,000 feet. RFTA viewed high altitude operation as the most challenging characteristic when it began considering the use of natural gas. RFTA is the second-largest public transit system in Colorado behind Denver's Regional Transportation District (RTD), and it is one of the largest rural public transit systems in the country. In 2013, RFTA accepted delivery of 22 new compressed natural gas (CNG) buses that went into service after completion of maintenance and refueling facilities earlier that year. This paper examines the lessons learned from RFTA's experience of investigating--and ultimately choosing--CNG for their new BRT program and focuses on the unique environment of RFTA's BRT application; the decision process to include CNG fueling in the project; unforeseen difficulties encountered in the operation of CNG buses; public perception; cost comparison to competing fuels; and considerations for indoor fueling facilities and project funding.

  20. THE COMPARATIVE ANALYSIS OF ECONOMIC DISPATCH AND OPTIMAL POWER FLOW METHODS FOR 22-BUS 380-kV POWER SYSTEM IN TURKEY

    Directory of Open Access Journals (Sweden)

    Mehmet KURBAN

    2007-03-01

    Full Text Available In this paper, the economic dispatch and optimal power flow (OPF methods for the purpose of supplying the load demand with minimum cost is used for 22-bus 380-kV power system in Turkey which consists of 8 thermal plants operated by EUAS (Electricity Generation Co. Inc.and the results found are analyzed comparatively. The results of analysis are given in tables and figures. The analysis made is implemented by the software using MATLAB®. Furthermore, the software can be used for different power systems by using the graphical user interface (GUI. All data used in this study is taken from TEIAS (Transmission System Operator of Turkey and EUAS.

  1. Effect of Extended State Observer and Automatic Voltage Regulator on Synchronous Machine Connected to Infinite Bus Power System

    Science.gov (United States)

    Angu, Rittu; Mehta, R. K.

    2018-04-01

    This paper presents a robust controller known as Extended State Observer (ESO) in order to improve the stability and voltage regulation of a synchronous machine connected to an infinite bus power system through a transmission line. The ESO-based control scheme is implemented with an automatic voltage regulator in conjunction with an excitation system to enhance the damping of low frequency power system oscillations, as the Power System Stabilizer (PSS) does. The implementation of PSS excitation control techniques however requires reliable information about the entire states, though they are not always directly measureable. To address this issue, the proposed ESO provides the estimate of system states as well as disturbance state together in order to improve not only the damping but also compensates system efficiently in presence of parameter uncertainties and external disturbances. The Closed-Loop Poles (CLPs) of the system have been assigned by the symmetric root locus technique, with the desired level of system damping provided by the dominant CLPs. The performance of the system is analyzed through simulating at different operating conditions. The control method is not only capable of providing zero estimation error in steady-state, but also shows robustness in tracking the reference command under parametric variations and external disturbances. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.

  2. Results of an electrical power system fault study

    Science.gov (United States)

    Dugal-Whitehead, Norma R.; Johnson, Yvette B.

    1992-01-01

    NASA-Marshall conducted a study of electrical power system faults with a view to the development of AI control systems for a spacecraft power system breadboard. The results of this study have been applied to a multichannel high voltage dc spacecraft power system, the Large Autonomous Spacecraft Electrical Power System (LASEPS) breadboard. Some of the faults encountered in testing LASEPS included the shorting of a bus an a falloff in battery cell capacity.

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

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Teodorescu, Remus; Rodriguez, Pedro

    2008-01-01

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

  4. Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid

    DEFF Research Database (Denmark)

    Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

    2016-01-01

    Power talk is a method for communication among voltage control sources (VSCs) in DC microgrids (MGs), achieved through variations of the supplied power that is incurred by modulation of the parameters of the primary control. The physical medium upon which the communication channel is established...

  5. Sliding-Mode Control of a Charger/Discharger DC/DC Converter for DC-Bus Regulation in Renewable Power Systems

    Directory of Open Access Journals (Sweden)

    Sergio Ignacio Serna-Garcés

    2016-03-01

    Full Text Available Stand-alone power systems based on renewable energy sources are used to replace generators based on fossil fuels. Those renewable power systems also require Energy Storage Devices (ESD interfaced by a charger/discharger power converter, which consist of a bidirectional DC/DC converter, and a DC bus. This paper proposes a single sliding-mode controller (SMC for the charger/discharger DC/DC converter to provide a stable DC bus voltage in any operation condition: charging or discharging the ESD, or even without any power exchange between the ESD and the DC bus. Due to the non-linear nature of the power converter, the SMC parameters are adapted on-line to ensure global stability in any operation condition. Such stability of the adaptive SMC is mathematically demonstrated using analytical expressions for the transversality, reachability and equivalent control conditions. Moreover, a design procedure for the adaptive SMC parameters is provided in order to ensure the dynamic response required for the correct operation of the load. Finally, simulations and experimental tests validate the proposed controller and design procedure.

  6. Comparison of candidate solar array maximum power utilization approaches. [for spacecraft propulsion

    Science.gov (United States)

    Costogue, E. N.; Lindena, S.

    1976-01-01

    A study was made of five potential approaches that can be utilized to detect the maximum power point of a solar array while sustaining operations at or near maximum power and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

  7. Development of a Rotary Engine Powered APU for a Medium Duty Hybrid Shuttle Bus

    National Research Council Canada - National Science Library

    McBroom, Scott

    1998-01-01

    Under contract to the TARDEC Petroleum and Water Business Area, sponsored by the Defense Advanced Research Projects Agency, SwRI has procured and installed a rotary Auxiliary Power Unit on a medium...

  8. ANALYSIS OF POWER SYSTEM RELIABILITY IMPROVEMENT FOR 74-BUS RADIAL DISTRIBUTION SYSTEM

    OpenAIRE

    Su Mon Myint*

    2018-01-01

    In Myanmar, electric power system planning is widely constructed because of more and more load growth and facing with failure of electricity, outage problems and system shut-down. Thus, not only making new power system network but also improving reliability of the existing system using suitable methods is very important to provide an adequate supply of electrical energy to its customers as economically and reliably as possible with an acceptable degree of continuity and quality that is design...

  9. Nonlinear Slewing Spacecraft Control Based on Exergy, Power Flow, and Static and Dynamic Stability

    Science.gov (United States)

    Robinett, Rush D.; Wilson, David G.

    2009-10-01

    This paper presents a new nonlinear control methodology for slewing spacecraft, which provides both necessary and sufficient conditions for stability by identifying the stability boundaries, rigid body modes, and limit cycles. Conservative Hamiltonian system concepts, which are equivalent to static stability of airplanes, are used to find and deal with the static stability boundaries: rigid body modes. The application of exergy and entropy thermodynamic concepts to the work-rate principle provides a natural partitioning through the second law of thermodynamics of power flows into exergy generator, dissipator, and storage for Hamiltonian systems that is employed to find the dynamic stability boundaries: limit cycles. This partitioning process enables the control system designer to directly evaluate and enhance the stability and performance of the system by balancing the power flowing into versus the power dissipated within the system subject to the Hamiltonian surface (power storage). Relationships are developed between exergy, power flow, static and dynamic stability, and Lyapunov analysis. The methodology is demonstrated with two illustrative examples: (1) a nonlinear oscillator with sinusoidal damping and (2) a multi-input-multi-output three-axis slewing spacecraft that employs proportional-integral-derivative tracking control with numerical simulation results.

  10. How to emit a high-power electron beam from a magnetospheric spacecraft?

    Science.gov (United States)

    Delzanno, G. L.; Lucco Castello, F.; Borovsky, J.; Miars, G.; Leon, O.; Gilchrist, B. E.

    2017-12-01

    The idea of using a high-power electron beam to actively probe magnetic-field-line connectivity in space has been discussed since the 1970's. It could solve longstanding questions in magnetospheric/ionospheric physics by establishing causality between phenomena occurring in the magnetosphere and their image in the ionosphere. However, this idea has never been realized onboard a magnetospheric spacecraft because the tenuous magnetospheric plasma cannot provide the return current necessary to keep the charging of the spacecraft under control. Recently, Delzanno et al. [1] have proposed a spacecraft-charging mitigation scheme to enable the emission of a high-power electron beam from a magnetospheric spacecraft. It is based on the plasma contactor, i.e. a high-density neutral plasma emitted prior to and with the electron beam. The contactor acts as an ion emitter (not as an electron collector, as previously thought): a high ion current can be emitted off the quasi-spherical contactor surface, without the strong space-charge limitations typical of planar ion beams, and the electron-beam current can be successfully compensated. In this work, we will discuss our theoretical/simulation effort to improve the understanding of contactor-based ion emission. First, we will present a simple mathematical model useful for the interpretation of the results of [1]. The model is in spherical geometry and the contactor dynamics is described by only two surfaces (its quasi-neutral surface and the front of the outermost ions). It captures the results of self-consistent Particle-In-Cell (PIC) simulations with good accuracy and highlights the physics behind the charge-mitigation scheme clearly. PIC simulations connecting the 1D model to the actual geometry of the problem will be presented to obtain the scaling of the spacecraft potential varying contactor emission area. Finally, results for conditions relevant to an actual mission will also be discussed. [1] G. L. Delzanno, J. E. Borovsky

  11. Power Quality Assessment in Real Shipboard Microgrid Systems under Unbalanced and Harmonic AC Bus Voltage

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Tarasiuk, Tomasz; Gorniak, Mariusz

    2018-01-01

    were proposed and carried out in a real ship under sea-going conditions to address this problem. The ship experimental results were presented and discussed considering non-linear bow thruster load and high power ballast pump loads under unbalanced and harmonic voltage conditions. In addition......, the analysis of voltage transient dips during ballast pump starting up is presented. Further, the voltage/current distortions of working generator, bow thruster and pump loads are analyzed. The paper provides a valuable analysis for coping with PQ issues in the real ship power system....

  12. Dual shear plate power processor packaging design. [for Solar Electric Propulsion spacecraft

    Science.gov (United States)

    Franzon, A. O.; Fredrickson, C. D.; Ross, R. G.

    1975-01-01

    The use of solar electric propulsion (SEP) for spacecraft primary propulsion imposes an extreme range of operational and environmental design requirements associated with the diversity of missions for which solar electric primary propulsion is advantageous. One SEP element which is particularly sensitive to these environmental extremes is the power processor unit (PPU) which powers and controls the electric ion thruster. An improved power processor thermal-mechanical packaging approach, referred to as dual shear plate packaging, has been designed to accommodate these different requirements with minimum change to the power processor design. Details of this packaging design are presented together with test results obtained from thermal-vacuum and structural-vibration tests conducted with prototype hardware.

  13. Bus basics

    International Nuclear Information System (INIS)

    Dobinson, R.W.

    1983-01-01

    The aims of this course are: 1. To introduce the general concepts of buses used to interconnect processors, perpherals, and instrumentation. 2. To classify, albeit crudely, different types of bus systems. 3. To give some examples of past, present, and future buses as applied to the field of high-energy physics, including some details of software. 4. To provide references for further study. (orig.)

  14. A digital, decentralized power station control system with bus-transmission facilitates the problem of backfitting

    International Nuclear Information System (INIS)

    Kaiser, G.E.; Schemmel, R.R.

    1985-01-01

    Current NPP control equipment technology is essentially characterized by the transmission of information in parallel using individual cables, and utilizes hardwired techniques for the processing of information. Progress in the area of semiconductor development characterized by micro-processors and LSI-circuits, has opened up new possibilities for the solution of the control tasks. The new power station control system PROCONTROL P utilizes these possibilities

  15. The LHC SSS cold mass inside the cryostat. The complexity of the bus-bars for the power supply of the magnets and cryogenic links can be seen. The two apertures in the centre will house the beam lines

    CERN Document Server

    2003-01-01

    The LHC SSS cold mass inside the cryostat. The complexity of the bus-bars for the power supply of the magnets and cryogenic links can be seen. The two apertures in the centre will house the beam lines

  16. A fast fault protection based on direction of bus-side capacitor discharge current for a high-surety power supply

    DEFF Research Database (Denmark)

    Li, Haijin; Chen, Min; Yang, Boping

    2017-01-01

    A short-circuit fault protection strategy based on the direction of bus-side capacitor discharge current for a high-surety power supply, known as Super Uninterruptable Power Supply (Super UPS), is studied in this paper. It consists of multiple energy sources and storage components. All energy...... strategy is necessary to keep the uninterruptable power for the critical load. In this paper, the characteristics of the short-circuit fault are analyzed first. Then, a fast short-circuit fault locating and isolating strategy based on the direction of the discharge current of the busside capacitors...

  17. Spacecraft radio scattering observations of the power spectrum of electron density fluctuations in the solar wind

    International Nuclear Information System (INIS)

    Woo, R.; Armstrong, J.W.

    1979-01-01

    Solar wind electron density power spectra in the solar equatorial region are inferred from observations of phase scintillations and spectral broadening made with the Viking, Helios, and Pioneer spacecraft. The heliocentric distance range covered is 2--215 R/sub S/, and for some observations close to the sun the spectra extend to fluctuation frequencies as high as 100 Hz. For heliocentric distances > or approx. =20 R/sub S/ the equivalent spacecraft-measured one-dimensional density spectrym V/sub n/e is well modeled by a single power law (f/sup -alpha/) in the frequency range 10 -4 -5 x 10 -2 Hz. The mean spectral index α is 1.65, very close to the Kolmogorov value of 5/3. Under the assumption of constant solar wind speed, V/sub n/e varies as R/sup -3.45/, where R is heliocentric distance. Within 20 R/sub S/, V/sub n/e can still be modeled by a single power law over the frequency range 10 -3 -10 1 Hz, but the spectral index becomes smaller, αapprox.1.1. The flattening of the density spectrum with 20 R/sub S/ is presumably associated with energy deposition in the near-sun region and acceleration of the solar wind

  18. DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (MACINTOSH A/UX VERSION)

    Science.gov (United States)

    Jagielski, J. M.

    1994-01-01

    The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

  19. DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (DEC VAX VMS VERSION)

    Science.gov (United States)

    Jagielski, J. M.

    1994-01-01

    The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

  20. Power Subsystem Design for Tiangong-1 Target Spacecraft%天宫一号目标飞行器电源分系统设计

    Institute of Scientific and Technical Information of China (English)

    陈启忠; 马季军; 王娜; 黄应春; 黄峥; 王振绪

    2011-01-01

    The sketch and main performances of the power subsystem of Tiangong-1 target spacecraft were introduced in this paper. The key technologies in domestic such as the bus with the voltage 100 V applied on low orbit spacecraft, large-scale nickel-metal hybrid batteries, triple-junction gallium arsenide solar cells and semi-rigid solar wings were given out. The main job of the high voltage device system establishing, the semi-rigid solar dynamics and space environment design and verification, the life time and reliability of the nickel-metal hybrid battery, and the reliability and safety of the high voltage power system were reviewed. The operation on orbit was given out. The research of the power subsystem of Tiangong-1 target spacecraft would establish the foundation for the China's next space technology.%介绍了天宫一号(TG1)目标飞行器电源分系统的组成和主要技术指标。分析了国内在低轨飞行器上采用100V高压母线、大批量使用国产氢镍电池、三结砷化镓太阳电池片和半刚性基板等关键技术。回顾了电源分系统研制过程中高电压元器件体系建立、半刚性帆板力学及空间环境设计与验证、氢镍电池在轨寿命和可靠性研究,以及高压电源系统可靠性及安全性研究等主要工作。给出了在轨运行情况。TG-1目标飞行器电源分系统的研制为我国后续空间技术的发展打下了基础。

  1. Power Management and Distribution Trades Studies for a Deep-Space Mission Scientific Spacecraft

    Science.gov (United States)

    Kimnach, Greg L.; Soltis, James V.

    2004-01-01

    As part of NASA's Project Prometheus, the Nuclear Systems Program, NASA GRC performed trade studies on the various Power Management and Distribution (PMAD) options for a deep-space scientific spacecraft which would have a nominal electrical power requirement of 100 kWe. These options included AC (1000Hz and 1500Hz and DC primary distribution at various voltages. The distribution system efficiency, reliability, mass, thermal, corona, space radiation levels and technology readiness of devices and components were considered. The final proposed system consisted of two independent power distribution channels, sourced by two 3-phase, 110 kVA alternators nominally operating at half-rated power. Each alternator nominally supplies 50kWe to one half of the ion thrusters and science modules but is capable of supplying the total power re3quirements in the event of loss of one alternator. This paper is an introduction to the methodology for the trades done to arrive at the proposed PMAD architecture. Any opinions expressed are those of the author(s) and do not necessarily reflect the views of Project Prometheus.

  2. A Preliminary Model for Spacecraft Propulsion Performance Analysis Based on Nuclear Gain and Subsystem Mass-Power Balances

    Science.gov (United States)

    Chakrabarti, Suman; Schmidt, George R.; Thio, Y. C.; Hurst, Chantelle M.

    1999-01-01

    A preliminary model for spacecraft propulsion performance analysis based on nuclear gain and subsystem mass-power balances are presented in viewgraph form. For very fast missions with straight-line trajectories, it has been shown that mission trip time is proportional to the cube root of alpha. Analysis of spacecraft power systems via a power balance and examination of gain vs. mass-power ratio has shown: 1) A minimum gain is needed to have enough power for thruster and driver operation; and 2) Increases in gain result in decreases in overall mass-power ratio, which in turn leads to greater achievable accelerations. However, subsystem mass-power ratios and efficiencies are crucial: less efficient values for these can partially offset the effect of nuclear gain. Therefore, it is of interest to monitor the progress of gain-limited subsystem technologies and it is also possible that power-limited systems with sufficiently low alpha may be competitive for such ambitious missions. Topics include Space flight requirements; Spacecraft energy gain; Control theory for performance; Mission assumptions; Round trips: Time and distance; Trip times; Vehicle acceleration; and Minimizing trip times.

  3. Global Precipitation Measurement (GPM) Spacecraft Lithium Ion Battery Micro-Cycling Investigation

    Science.gov (United States)

    Dakermanji, George; Lee, Leonine; Spitzer, Thomas

    2016-01-01

    The Global Precipitation Measurement (GPM) spacecraft was jointly developed by NASA and JAXA. It is a Low Earth Orbit (LEO) spacecraft launched on February 27, 2014. The power system is a Direct Energy Transfer (DET) system designed to support 1950 watts orbit average power. The batteries use SONY 18650HC cells and consist of three 8s by 84p batteries operated in parallel as a single battery. During instrument integration with the spacecraft, large current transients were observed in the battery. Investigation into the matter traced the cause to the Dual-Frequency Precipitation Radar (DPR) phased array radar which generates cyclical high rate current transients on the spacecraft power bus. The power system electronics interaction with these transients resulted in the current transients in the battery. An accelerated test program was developed to bound the effect, and to assess the impact to the mission.

  4. Hybrid Electric Transit Bus

    Science.gov (United States)

    Viterna, Larry A.

    1997-01-01

    A government, industry, and university cooperative is developing an advanced hybrid electric city transit bus. Goals of this effort include doubling the fuel economy compared to current buses and reducing emissions to one-tenth of current EPA standards. Unique aspects of the vehicle's power system include the use of ultra-capacitors as an energy storage system, and a planned natural gas fueled turbogenerator developed from a small jet engine. Power from both the generator and energy storage system is provided to a variable speed electric motor attached to the rear axle. At over 15000 kg gross weight, this is the largest vehicle of its kind ever built using ultra-capacitor energy storage. This paper describes the overall power system architecture, the evolution of the control strategy, and its performance over industry standard drive cycles.

  5. Analysis of a diesel-electric hybrid urban bus system

    Science.gov (United States)

    Marr, W. W.; Sekar, R. R.; Ahlheim, M. C.

    A hybrid bus powered by a diesel engine and a battery pack was analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, were evaluated. The results indicate that the fuel economy of a hybrid bus, taking into account the regenerative braking, is comparable with that of a conventional diesel bus. Life-cycle costs are slightly higher because of the added weight and cost of the battery.

  6. GO Bus impact analysis.

    Science.gov (United States)

    2013-08-01

    NJ TRANSIT launched two relatively new enhanced bus services: GO 25 serving the : Springfield Avenue corridor in 2008 and GO 28 serving the Bloomfield Avenue corridor in 2009. : As an enhanced but not full Bus Rapid Transit (BRT) service, GO Bus feat...

  7. Spacecraft Trajectory Generation by Successive Approximation for Powered Descent and Cyclers

    Science.gov (United States)

    Casoliva, Jordi

    Methods for spacecraft trajectory generation must be reliable. Complex nonlinear dynamics and constraints impede straightforward approaches. The approach pursued in this dissertation is to use successive approximation, which entails solving a sequence of problems, each one of which can be solved reliably, leading to the solution of the problem of interest. First, contractive sequential convex programming (CSCP) is developed and then applied to the problem of optimal powered descent landing in the presence of complex constraints, aerodynamic force and nonlinear engine performance. Second, numerical continuation is applied to the generation of cycler (periodic) spacecraft trajectories in the Earth-Moon system, the challenge here being the multiple scales of the three-body dynamics. The first-order necessary conditions for minimum-fuel powered descent are derived and interpreted. Both a point-mass model with throttle and thrust angle control and a rigid-body model with throttle and angular velocity control are considered, with a more complete analysis of the rigid-body case than previously available in the literature. The effects of boundary conditions on the thrust direction and finite bounds on the angular velocities are analyzed for the rigid-body case. Minimum-fuel solutions, obtained numerically, illustrate the optimal strategies. The optimal powered descent landing problem considered in the development of CSCP has a convex cost function, nonlinear dynamics, convex state constraints and nonlinear non-convex control constraints. The non-convexity in the control constraints is handled with the lossless convexification technique which consists of a convex relaxation on the control constraints. The novelty of CSCP is the ability to account for nonlinear dynamics and nonlinear control bounds in the optimal control problem and the use of interior-point methods for second-order cone programs which are guaranteed to find the optimal solution. CSCP solves a convergent

  8. Based on enterprise data bus realizing data transfer of engineering management information system in the nuclear power plant

    International Nuclear Information System (INIS)

    Shen Lin

    2014-01-01

    The data transfer of the system in the plant does not simply package the data by category, but analyze systematically the data in project management, identify basic data of the system for operations, group the data, and analyze their types, so as to ensure accuracy and quality of data transfer. the data transfer of engineering management information systems in the plant is the key of efficient operations of information systems. Its data quality will directly affect. equipment material management efficiency and maintenance. Therefore based on the nature of enterprise data bus, it can standardize data transfer. by developing reasonable transfer strategy by stage, it can decompose the heavy task of transferring calibration into the full process of engineering construction. combined with the quality assurance system of data transfer, transfer quality can be guaranteed in the whole process, so as to achieve a smooth transition from information systems in engineering construction to those in operation. (author)

  9. Elimination of bus voltage impact on temperature sensitive electrical parameter during turn-on transition for junction temperature estimation of high-power IGBT modules

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

    2017-01-01

    Junction temperature is of great importance to safe operating area of IGBT modules. Various information of the IGBT operating state is reflected on electrical characteristics during turn-on transient. A unified extraction method for internal junction temperature via dynamic thermo......-sensitive electrical parameters (DTSEP) during turn-on transient is proposed. Two DTSEP, turn-on delay time (tdon) and the maximum increasing rate of collector current dic/dt(max), are combined to eliminate the bus voltage impact. Using the inherent emitter-auxiliary inductor LeE in high-power modules, the temperature......-dependent DTSEPs can be converted into a low-voltage and measurable signal. Finally, experiment results are exhibited to verify the effectiveness of proposed method....

  10. Intelligent Bus Stops in the Flexible Bus Systems

    OpenAIRE

    Razi Iqbal; Muhammad Usman Ghani

    2014-01-01

    The purpose of this paper is to discuss Intelligent Bus Stops in a special Demand Responsive Transit (DRT), the Flexible Bus System. These Intelligent Bus Stops are more efficient and information rich than Traditional Bus Stops. The real time synchronization of the Flexible Bus System makes it unique as compared to Traditional Bus Systems. The Main concern is to make Bus Stops intelligent and information rich. Buses are informed about the no. of passengers waiting at the upcoming ...

  11. Standardized spacecraft: a methodology for decision making. AMS report No. 1199

    International Nuclear Information System (INIS)

    Greenberg, J.S.; Nichols, R.A.

    1974-01-01

    As the space program matures, more and more attention is being focused on ways to reduce the costs of performing space missions. Standardization has been suggested as a way of providing cost reductions. The question of standardization at the system level, in particular, the question of the desirability of spacecraft standardization for geocentric space missions is addressed. The spacecraft is considered to be a bus upon which mission oriented equipment, the payload, is mounted. Three basic questions are considered: (1) is spacecraft standardization economically desirable; (2) if spacecraft standardization is economically desirable, what standardized spacecraft configuration or mix of configurations and technologies should be developed; and (3) if standardized spacecraft are to be developed, what power levels should they be designed for. A methodology which has been developed and which is necessary to follow if the above questions are to be answered and informed decisions made relative to spacecraft standardization is described. To illustrate the decision making problems and the need for the developed methodology and the data requirements, typical standardized spacecraft have been considered. Both standardized solar and nuclear-powered spacecraft and mission specialized spacecraft have been conceptualized and performance and cost estimates have been made. These estimates are not considered to be of sufficient accuracy to allow decisions regarding spacecraft mix and power levels to be made at this time. The estimates are deemed of sufficient accuracy so as to demonstrate the desirability of spacecraft standardization and the methodology (as well as the need for the methodology) which is necessary to decide upon the best mix of standardized spacecraft and their design power levels. (U.S.)

  12. System Critical Design Audit (CDA). Books 1, 2 and 3; [Small Satellite Technology Initiative (SSTI Lewis Spacecraft Program)

    Science.gov (United States)

    1995-01-01

    Small Satellite Technology Initiative (SSTI) Lewis Spacecraft Program is evaluated. Spacecraft integration, test, launch, and spacecraft bus are discussed. Payloads and technology demonstrations are presented. Mission data management system and ground segment are also addressed.

  13. NOC AND BUS ARCHITECTURE: A COMPARISON

    OpenAIRE

    RAJEEV KAMAL; NEERAJ YADAV

    2012-01-01

    Network-on-chip designs promise to offer considerable advantages over the traditional bus-based architecture. As continuing scaling of Moore’s law enables ever greater transistor densities, design complexity, power limitations and application convergence networks have started to replace busses in much smaller systems and the enhancement of NoC. This paper summarizes the advantages of the NoC and the limitations of traditional bus based architecture. In this paper we discuss a detailed compari...

  14. Estimating bus passenger waiting times from incomplete bus arrivals data

    OpenAIRE

    McLeod, F.N.

    2007-01-01

    This paper considers the problem of estimating bus passenger waiting times at bus stops using incomplete bus arrivals data. This is of importance to bus operators and regulators as passenger waiting time is a key performance measure. Average waiting times are usually estimated from bus headways, that is, time gaps between buses. It is both time-consuming and expensive to measure bus arrival times manually so methods using automatic vehicle location systems are attractive; however, these syste...

  15. Intelligent Bus Stops in the Flexible Bus Systems

    Directory of Open Access Journals (Sweden)

    Razi Iqbal

    2014-09-01

    Full Text Available The purpose of this paper is to discuss Intelligent Bus Stops in a special Demand Responsive Transit (DRT, the Flexible Bus System. These Intelligent Bus Stops are more efficient and information rich than Traditional Bus Stops. The real time synchronization of the Flexible Bus System makes it unique as compared to Traditional Bus Systems. The Main concern is to make Bus Stops intelligent and information rich. Buses are informed about the no. of passengers waiting at the upcoming Bus Stops. If there are no passengers to ride or get off on upcoming Bus Stop, the Bus can skip that Bus Stop and head towards the next Bus Stop where passenger is waiting, which will decrease the ride time of the passengers on the Bus and also the wait time of the passengers waiting on the upcoming Bus Stops. Providing more information at Bus Stops about the Destination (Time to Destination, Distance to Destination etc. and Buses (Bus Location, Arrival Time of Bus etc. makes it easier for the passengers to decide whether to ride a particular Bus or not.

  16. TPG bus passes

    CERN Multimedia

    Staff Association

    2013-01-01

    The CERN Staff Association will stop selling TPG bus passes. All active and retired members of the CERN personnel will be able to purchase Unireso bus passes from the CERN Hostel - Building 39 (Meyrin site) from 1st February 2013. For more information: https://cds.cern.ch/journal/CERNBulletin/2013/04/Announcements/1505279?ln=en

  17. The Development of Fuel Cell Technology for Electric Power Generation - From Spacecraft Applications to the Hydrogen Economy

    Science.gov (United States)

    Scott, John H.

    2005-01-01

    The fuel cell uses a catalyzed reaction between a fuel and an oxidizer to directly produce electricity. Its high theoretical efficiency and low temperature operation made it a subject of much study upon its invention ca. 1900, but its relatively high life cycle costs kept it as "solution in search of a problem" for its first half century. The first problem for which fuel cells presented a cost effective solution was, starting in the 1960's that of a power source for NASA's manned spacecraft. NASA thus invested, and continues to invest, in the development of fuel cell power plants for this application. However, starting in the mid-1990's, prospective environmental regulations have driven increased governmental and industrial interest in "green power" and the "Hydrogen Economy." This has in turn stimulated greatly increased investment in fuel cell development for a variety of terrestrial applications. This investment is bringing about notable advances in fuel cell technology, but these advances are often in directions quite different from those needed for NASA spacecraft applications. This environment thus presents both opportunities and challenges for NASA's manned space program.

  18. Design and operation of the 30-MJ superconducting magnetic-storage system on the Bonneville Power Administration bus

    International Nuclear Information System (INIS)

    Schermer, R.I.; Barron, M.H.; Boenig, H.J.

    1983-01-01

    A superconducting magnetic-energy-storage (SMES) unit is suitable for power-system stabilization because it can provide positive damping by absorbing or releasing energy with a relatively fast response time, 10 ms. In the fall of 1982, an SMES unit was installed at the Tacoma Substation of the Bonneville Power Administration as an experiment in monitoring, predicting and improving system stability. This paper reports principally on the system testing

  19. Development of an autonomous power system testbed

    International Nuclear Information System (INIS)

    Barton, J.R.; Adams, T.; Liffring, M.E.

    1985-01-01

    A power system testbed has been assembled to advance the development of large autonomous electrical power systems required for the space station, spacecraft, and aircraft. The power system for this effort was designed to simulate single- or dual-bus autonomous power systems, or autonomous systems that reconfigure from a single bus to a dual bus following a severe fault. The approach taken was to provide a flexible power system design with two computer systems for control and management. One computer operates as the control system and performs basic control functions, data and command processing, charge control, and provides status to the second computer. The second computer contains expert system software for mission planning, load management, fault identification and recovery, and sends load and configuration commands to the control system

  20. SoC-Based Dynamic Power Sharing Method with AC-Bus Voltage Restoration for Microgrid Applications

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.

    2012-01-01

    In a microgrid system, distributed energy storage units are commonly employed as the energy buffers. In this paper, a dynamic power sharing method based on the state-of-charge (SoC) of each energy storage unit is proposed. Droop control is employed as the basic control strategy for the distributed...

  1. Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

    Science.gov (United States)

    Mengshoel, Ole Jakob; Poll, Scott; Kurtoglu, Tolga

    2009-01-01

    In this paper, we investigate the use of Bayesian networks to construct large-scale diagnostic systems. In particular, we consider the development of large-scale Bayesian networks by composition. This compositional approach reflects how (often redundant) subsystems are architected to form systems such as electrical power systems. We develop high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems. The largest among these 24 Bayesian networks contains over 1,000 random variables. Another BN represents the real-world electrical power system ADAPT, which is representative of electrical power systems deployed in aerospace vehicles. In addition to demonstrating the scalability of the compositional approach, we briefly report on experimental results from the diagnostic competition DXC, where the ProADAPT team, using techniques discussed here, obtained the highest scores in both Tier 1 (among 9 international competitors) and Tier 2 (among 6 international competitors) of the industrial track. While we consider diagnosis of power systems specifically, we believe this work is relevant to other system health management problems, in particular in dependable systems such as aircraft and spacecraft. (See CASI ID 20100021910 for supplemental data disk.)

  2. Damage-Tolerant, Lightweight, High-Temperature Radiator for Nuclear Powered Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Game-changing propulsion systems are often enabled by novel designs using advanced materials. Radiator performance dictates power output for nuclear electric...

  3. The erigone bus study

    International Nuclear Information System (INIS)

    Durieu, L.; Vignes, M.; Wolstenholme, P.

    1982-01-01

    A study has been made of some factors determining the performance and cost-effectiveness of microcomputer bus systems implemented in Europa crates. An experimental system has been specified and a number of modules constructed in accordance with the specification, in order to test the validity of some of the ideas proposed. It has been demonstrated that the bus interfacing logic can be simple and inexpensive, while maintaining a high degree of processor independence and also a high degree of transparency in operation. The number of pins required by the bus is minimized by multiplexing address and data. A series termination for the drive of the multiplexed lines permits cross-talk to be reduced to insignificant levels: this technique is recommended for wider application. The experimental bus is proposed as a basis for the construction of simple microcomputer-based instrumentation systems. (orig.)

  4. Creative Bus Financing.

    Science.gov (United States)

    Malone, Wade

    1982-01-01

    Alternative ways of financing school bus purchases include financing privately through contractors or commercial banks, financing through sources such as insurance companies and pension funds, leasing the buses, or contracting for transportation services. (Author/MLF)

  5. LHC on the bus

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    On 15 December, an airport bus will be transformed in the image of CERN. The bus will be seen by the thousands of travellers arriving in Geneva, informing them of the possibility to visit CERN.   Sketch of the bus. The good relationship between Geneva International Airport and CERN started several years ago. In 2004 the airport put advertising space in the arrivals area at CERN's disposal free of charge. Now, starting on 15 December, a 40-foot long bus will display a giant sticker advertisement depicting CERN as it takes passengers over the airport tarmac to their planes. This is no ordinary sticker, and it was no mean task to attach it to the bus. The task of producing and attaching it was entrusted to Geneva-based specialists Mathys SA. With the ski season opening on 15 December, there will be many travellers arriving at the airport, and the bus will be ready to receive them. When one thinks of CERN, the subjects that naturally come to mind are the LHC, the mysteries of the Universe...

  6. PyBus -- A Python Software Bus

    OpenAIRE

    Lavrijsen, W

    2005-01-01

    A software bus, just like its hardware equivalent, allows for the discovery, installation, configuration, loading, unloading, and run-time replacement of software components, as well as channeling of inter-component communication. Python, a popular open-source programming language, encourages a modular design on software written in it, but it offers little or no component functionality. However, the language and its interpreter provide sufficient hooks to implement a thin, integral layer...

  7. Project-based learning applied to spacecraft power systems: a long-term engineering and educational program at UPM University

    Science.gov (United States)

    Pindado, Santiago; Cubas, Javier; Roibás-Millán, Elena; Sorribes-Palmer, Félix

    2018-03-01

    The IDR/UPM Institute is the research center responsible for the Master in Space Systems (MUSE) of Universidad Politécnica de Madrid (UPM). This is a 2-year (120 ECTS) master's degree focused on space technology. The UPMSat-2 satellite program has become an excellent educational framework in which the academic contents of the master are trained through project-based learning and following a multidisciplinary approach. In the present work, the educational projects developed and carried out in relation to spacecraft power systems at the IDR/UPM Institute are described. These projects are currently being developed in the framework represented by the aforementioned MUSE master's program and UPMSat-2.

  8. The Global Precipitation Measurement (GPM Spacecraft Power System Design and Orbital Performance

    Directory of Open Access Journals (Sweden)

    Dakermanji George

    2017-01-01

    The paper describes the power system design details, its performance to date and the lithium ion battery model that was developed for use in the energy balance analysis and is being used to predict the on-orbit health of the battery.

  9. N2O4 as a working substance for a spacecraft power plant

    International Nuclear Information System (INIS)

    Popyrin, L.S.; Starostenko, N.N.; Starostenko, V.I.

    1975-01-01

    A gas turbine cycle on dissociating nitrogen tetroxide (N 2 O 4 ) as working medium is considered. Nitrogen tetroxide has a number of properties advantageous in this respect. A direct cycle power plant is considered. A fast reactor with a gas coolant is an energy source. Some versions of a power plant have been analysed for the gas temperature at the turbine inlet ranging from 1170 to 1470 K. The cycle efficiency is found to increase considerably with the working medium temperature rise at the turbine inlet only to 1380-1400 K. To determine the efficiency of the plants of this type, they are compared to identical designs of gas and gas-liquid cycles on alkali metals, inert gases and dissociating phosphorus. Theoretical and experimental data show that the turbine with nitrogen tetroxide as working medium is more compact in comparison to that with inert gases. Small specific surfaces of the radiator, small size of the turbine and thermal process equipment, and high efficiency are evidence of the advisability of using the plant of the type considered as on-board power plant of a space ship

  10. The established mega watt linear programming-based optimal power flow model applied to the real power 56-bus system in eastern province of Saudi Arabia

    International Nuclear Information System (INIS)

    Al-Muhawesh, Tareq A.; Qamber, Isa S.

    2008-01-01

    A current trend in electric power industries is the deregulation around the world. One of the questions arise during any deregulation process is: where will be the future generation expansion? In the present paper, the study is concentrated on the wheeling computational method as a part of mega watt (MW) linear programming-based optimal power flow (LP-based OPF) method. To observe the effects of power wheeling on the power system operations, the paper uses linear interactive and discrete optimizer (LINDO) optimizer software as a powerful tool for solving linear programming problems to evaluate the influence of the power wheeling. As well, the paper uses the optimization tool to solve the economic generation dispatch and transmission management problems. The transmission line flow was taken in consideration with some constraints discussed in this paper. The complete linear model of the MW LP-based OPF, which is used to know the future generation potential areas in any utility is proposed. The paper also explains the available economic load dispatch (ELD) as the basic optimization tool to dispatch the power system. It can be concluded in the present study that accuracy is expensive in terms of money and time and in the competitive market enough accuracy is needed without paying much

  11. Common bus multinode sensor system

    International Nuclear Information System (INIS)

    Kelly, T.F.; Naviasky, E.H.; Evans, W.P.; Jefferies, D.W.; Smith, J.R.

    1988-01-01

    This patent describes a nuclear power plant including a common bus multinode sensor system for sensors in the nuclear power plant, each sensor producing a sensor signal. The system consists of: a power supply providing power; a communication cable coupled to the power supply; plural remote sensor units coupled between the cable and one or more sensors, and comprising: a direct current power supply, connected to the cable and converting the power on the cable into direct current; an analog-to-digital converter connected to the direct current power supply; an oscillator reference; a filter; and an integrated circuit sensor interface connected to the direct current power supply, the analog-to-digital converter, the oscillator crystal and the filter, the interface comprising: a counter receiving a frequency designation word from external to the interface; a phase-frequency comparator connected to the counter; an oscillator connected to the oscillator reference; a timing counter connected to the oscillator, the phase/frequency comparator and the analog-to-digital converter; an analog multiplexer connectable to the sensors and the analog-to-digital converter, and connected to the timing counter; a shift register operatively connected to the timing counter and the analog-to-digital converter; an encoder connected to the shift register and connectable to the filter; and a voltage controlled oscillator connected to the filter and the cable

  12. Magnesium fluoride as energy storage medium for spacecraft solar thermal power systems

    Science.gov (United States)

    Lurio, Charles A.

    1992-01-01

    MgF2 was investigated as a phase-change energy-storage material for LEO power systems using solar heat to run thermal cycles. It provides a high heat of fusion per unit mass at a high melting point (1536 K). Theoretical evaluation showed the basic chemical compatibility of liquid MgF2 with refractory metals at 1600 K, though transient high pressures of H2 can occur in a closed container due to reaction with residual moisture. The compatibility was tested in two refractory metal containers for over 2000 h. Some showed no deterioration, while there was evidence that the fluoride reacted with hafnium in others. Corollary tests showed that the MgF2 supercooled by 10-30 K and 50-90 K.

  13. Learning NServiceBus

    CERN Document Server

    Boike, David

    2013-01-01

    This is a practical tutorial containing hands-on examples for creating a messaging and SOA based service bus.This book is for .NET developers who are looking for ways to overcome problems related to buggy third party web service integrations, codebases that have grown into a big ball of mud, and batch jobs failure.

  14. Miniature, Low-Power, Waveguide Based Infrared Fourier Transform Spectrometer for Spacecraft Remote Sensing

    Science.gov (United States)

    Hewagama, TIlak; Aslam, Shahid; Talabac, Stephen; Allen, John E., Jr.; Annen, John N.; Jennings, Donald E.

    2011-01-01

    Fourier transform spectrometers have a venerable heritage as flight instruments. However, obtaining an accurate spectrum exacts a penalty in instrument mass and power requirements. Recent advances in a broad class of non-scanning Fourier transform spectrometer (FTS) devices, generally called spatial heterodyne spectrometers, offer distinct advantages as flight optimized systems. We are developing a miniaturized system that employs photonics lightwave circuit principles and functions as an FTS operating in the 7-14 micrometer spectral region. The inteferogram is constructed from an ensemble of Mach-Zehnder interferometers with path length differences calibrated to mimic scan mirror sample positions of a classic Michelson type FTS. One potential long-term application of this technology in low cost planetary missions is the concept of a self-contained sensor system. We are developing a systems architecture concept for wide area in situ and remote monitoring of characteristic properties that are of scientific interest. The system will be based on wavelength- and resolution-independent spectroscopic sensors for studying atmospheric and surface chemistry, physics, and mineralogy. The self-contained sensor network is based on our concept of an Addressable Photonics Cube (APC) which has real-time flexibility and broad science applications. It is envisaged that a spatially distributed autonomous sensor web concept that integrates multiple APCs will be reactive and dynamically driven. The network is designed to respond in an event- or model-driven manner or reconfigured as needed.

  15. Massachusetts Fuel Cell Bus Project: Demonstrating a Total Transit Solution for Fuel Cell Electric Buses in Boston

    Energy Technology Data Exchange (ETDEWEB)

    2017-05-22

    The Federal Transit Administration's National Fuel Cell Bus Program focuses on developing commercially viable fuel cell bus technologies. Nuvera is leading the Massachusetts Fuel Cell Bus project to demonstrate a complete transit solution for fuel cell electric buses that includes one bus and an on-site hydrogen generation station for the Massachusetts Bay Transportation Authority (MBTA). A team consisting of ElDorado National, BAE Systems, and Ballard Power Systems built the fuel cell electric bus, and Nuvera is providing its PowerTap on-site hydrogen generator to provide fuel for the bus.

  16. Testing of Environmental Satellite Bus-Instrument Interfaces Using Engineering Models

    Science.gov (United States)

    Gagnier, Donald; Hayner, Rick; Nosek, Thomas; Roza, Michael; Hendershot, James E.; Razzaghi, Andrea I.

    2004-01-01

    This paper discusses the formulation and execution of a laboratory test of the electrical interfaces between multiple atmospheric scientific instruments and the spacecraft bus that carries them. The testing, performed in 2002, used engineering models of the instruments and the Aura spacecraft bus electronics. Aura is one of NASA s Earth Observatory System missions. The test was designed to evaluate the complex interfaces in the command and data handling subsystems prior to integration of the complete flight instruments on the spacecraft. A problem discovered during the flight integration phase of the observatory can cause significant cost and schedule impacts. The tests successfully revealed problems and led to their resolution before the full-up integration phase, saving significant cost and schedule. This approach could be beneficial for future environmental satellite programs involving the integration of multiple, complex scientific instruments onto a spacecraft bus.

  17. Circuit breaker and bus

    International Nuclear Information System (INIS)

    Vogel, H.F.

    1978-01-01

    Two close-open operations are required each pulse cycle at approximately 3 MA with the breaker in series with the burn supply, both forming a leg in parallel with the E-coil and the homopolar. To conduct the 3-MA current, approximately 30 breaker units are connected in parallel. Each unit is equipped with a counterpulse capacitor bank, and the bus for the 30 units is provided with a common saturable reactor core made of strip steel wound around the bus. Oil breakers of a special design are chosen because of their high arc resistance facilitating the current transfer to the homopolar machine and for obtaining precision timing in opening and closing of the contacts. The precision timing is achieved by a shock wave method with the oil serving as hydraulic medium. Each of the parallel breaker units possesses two sets of contacts, a stationary and a transient one. A 1-mΩ resistor in series with the transient contacts of each breaker unit is to improve the current sharing. The bus consists of room temperature copper, stranded and transposed to help provide current equalization under transient conditions

  18. Dynamic Isotope Power System (DIPS) Applications Study. Volume II. Nuclear Integrated Multimission Spacecraft (NIMS) design definition. Final report

    International Nuclear Information System (INIS)

    1979-11-01

    The design requirements for the Nuclear Integrated Multimission Spacecraft. (NIMS) are discussed in detail. The requirements are a function of mission specifications, payload, control system requirements, electric system specifications, and cost limitations

  19. Swisstrolley 3 - An articulated trolley bus; SWISSTROLLEY 3. Gelenktrolleybus

    Energy Technology Data Exchange (ETDEWEB)

    Gisler, H.-J.

    2006-07-01

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at the Swisstrolley 3 low-floor, articulated trolley bus developed in Switzerland by the Hess AG company. Various features of the variants of the trolley bus, including single vehicle, single and double-articulated buses and bus trailers, are discussed. The reductions achieved in energy consumption, weight and noise are discussed. Typical values for power consumption are presented in graphical form. Economic viability and passenger-friendliness are examined, as are possibilities for further improvement.

  20. Miniature JPL Universal Instrument Bus

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop a Universal Digital Processor Bus architecture using state of the art commercial packaging technologies. This work will transition commercial advanced- yet...

  1. Digital bus technology in new coal-fired plants

    Energy Technology Data Exchange (ETDEWEB)

    Blaney, J.; Murray, J. [Emerson Process Management (United States)

    2007-10-15

    The main issues associated with including digital bus technology such as Foundation fieldbus, Profibus-DP or DeviceNet, in a coal-fired power plant are deciding which systems to install and determining how to implement it. Although still new, digital bus experiences to date have shown that the technology performs solidly and when wiring best practices are followed a significantly shorted commissioning cycle can be achieved. 1 fig., 2 tabs.

  2. 1393 Ring Bus at JPL: Description and Status

    Science.gov (United States)

    Wysocky, Terry R.

    2007-01-01

    Completed Ring Bus IC V&V Phase - Ring Bus Test Plan Completed for SIM Project - Applicable to Other Projects Implemented a Avionics Bus Based upon the IEEE 1393 Standard - Excellent Starting Point for a General Purpose High-Speed Spacecraft Bus - Designed to Meet SIM Requirements for - Real-time deterministic, distributed systems. - Control system requirements - Fault detection and recovery Other JPL Projects Considering Implementation F'light Software Ring Bus Driver Module Began in 2006, Continues Participating in Standard Revision. Search for Earth-like planets orbiting nearby stars and measure the masses and orbits of the planets it finds. Survey 2000 nearby stars for planetary systems to learn whether our Solar System is unusual, or typical. Make a new catalog of star position 100 times more accurate than current measurements. Learn how our galaxy formed and will evolve by studying the dynamics of its stars. Critically test models of exactly how stars shine, including exotic objects like black holes, neutron stars and white dwarfs.

  3. Dips spacecraft integration issues

    International Nuclear Information System (INIS)

    Determan, W.R.; Harty, R.B.

    1988-01-01

    The Department of Energy, in cooperation with the Department of Defense, has recently initiated the dynamic isotope power system (DIPS) demonstration program. DIPS is designed to provide 1 to 10 kW of electrical power for future military spacecraft. One of the near-term missions considered as a potential application for DIPS was the boost surveillance and tracking system (BSTS). A brief review and summary of the reasons behind a selection of DIPS for BSTS-type missions is presented. Many of these are directly related to spacecraft integration issues; these issues will be reviewed in the areas of system safety, operations, survivability, reliability, and autonomy

  4. Project survey for trolley-bus transport; Johdinautoliikenteen hankeselvitys

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, T.; Eklund, P.; Airaksinen, S.; Maettoe, R.; Laehdetie, A.

    2011-04-15

    To investigate the feasibility and rationality of the revival of trolley bus traffic in Helsinki a full size project plan was conducted for a variety of alternatives. This included a survey on the latest developments of the trolley bus technology, three optional plans for route network, a budgetary level design for a fully functional depot in Koskela bus depot, examination of urban landscape structures, a study on organisational options, particular technical specifications applicable on suitable trolley buses and an examination of the impacts on the environment and on the future development of public transport. The basic concept of a trolley bus as a means of electric public transport vehicle has found its form over the years, but all the components of the system undergo at present intensive development. In context of this survey also the option of a fully autonomous electric bus powered by accumulators or fuel cells and the like was investigated. However, such technology is still totally inadequate for a heavy duty bus. There are no economically competitive and effective systems available as yet. The trolley bu is the far most reliable system and gives the best life cycle economy for a foreseeable future. Earliest estimates for alternative electric technologies in regular bus service are viable just after one investment cycle some time beyond 2030. Then it should be possible to run without the support of a comprehensive overhead line. The latest achievements in the development of trolley bus are auxiliary engine and accumulator systems allowing for more autonomous propulsion. Nowadays, trolley buses are equipped with an auxiliary power unit that alleviates the traditional restrictions of the overhead line. The modern trolley bus may run short distances without the trolley lines. Recuperation of the kinetic energy at deceleration (braking) either into the overhead line network or by storing it in the vehicle is one of the characteristics of modern trolley buses

  5. Learning NServiceBus Sagas

    CERN Document Server

    Helton, Rich

    2015-01-01

    If you are an Enterprise C# developer who wishes to extend your knowledge of NServiceBus and Enterprise Service Bus in C#, this is the book for you. This book is designed to enhance the education of ESBs and their messaging, whether you are a beginner or a seasoned expert in Enterprise C#, Apex, and Visualforce pages.

  6. Brazilian hybrid electric fuel cell bus

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, P.E.V.; Carreira, E.S. [Coppe-Federal Univ. of Rio de Janeiro (Brazil). Hydrogen Lab.

    2010-07-01

    The first prototype of a hybrid electric fuel cell bus developed with Brazilian technology is unveiled. It is a 12 m urban-type, low-floor, air-conditioned bus that possesses three doors, air suspension, 29 seats and reversible wheelchair site. The bus body was built based on a double-deck type monoblock vehicle that is able to sustain important load on its roof. This allowed positioning of the type 3 hydrogen tanks and the low weight traction batteries on the roof of the vehicles without dynamic stabilization problems. A novel hybrid energy configuration was designed in such a way that the low-power (77 kWe) fuel cell works on steady-state operation mode, not responding directly to the traction motor load demand. The rate of kinetic energy regeneration upon breaking was optimized by the use of an electric hybrid system with predominance of batteries and also by utilizing supercapacitors. The electric-electronic devices and the security control softwares for the auxiliary and traction systems were developed in-house. The innovative hybrid-electric traction system configuration led to the possibility to decrease the fuel cell power, with positive impact on weight and system volume reduction, as well as to significantly decrease the hydrogen consumption. (orig.)

  7. SEDS MIL-STD-1773 fiber optic data bus: Proton irradiation test results and spaceflight SEU data

    Energy Technology Data Exchange (ETDEWEB)

    LaBel, K.A.; Stassinopoulos, E.G.; Miller, J.T. (NASA/GSFC, Greenbelt, MD (United States)); Marshall, P. (NRL/SFA, Washington, DC (United States)); Dale, C. (NRL, Washington, DC (United States)); Crabtree, C.M. (Hughes/ST Systems Corp., Seabrook, MD (United States)); Gates, M.M. (Jackson and Tull, Seabrook, MD (United States))

    1993-12-01

    The Small Explorer Data System (SEDS) was launched in July of 1992 as part of the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) mission. The SEDS utilizes NASA's first MIL-STD-1773 Fiber Optic Multiplexed Data Bus (or 1773 bus) to communicate with other spacecraft subsystems in the space environment. The 1773 bus is the fiber optic version of the MIL-STD-1553 Data Bus, a electronic wire bus used in many avionics applications. The authors present proton test and space flight single event effect data for NASA's first fiber optic data bus. Bit error rate predictions based on a new proton direct ionization model agree well with flight data for proton belt and solar flare effects.

  8. 76 FR 37184 - Discretionary Bus and Bus Facilities Program

    Science.gov (United States)

    2011-06-24

    ... transporting bicycles on public transportation vehicles. The FY 2011 Appropriations Act allows a 90 percent Federal share for the total cost of a biodiesel bus. The Act also allows a 90 percent Federal share for...

  9. Air-pollution and economics: diesel bus versus electric bus

    OpenAIRE

    Adheesh, SR; Vasisht, Shravanth M; Ramasesha, Sheela K

    2016-01-01

    The Bangalore Metropolitan Transport Corporation (BMTC) took an initiative to check the overall benefits of introducing electric buses as a suitable replacement for the diesel buses to tackle the burgeoning pollution in the city of Bengaluru, India. For a trial run of three months, an electric bus was procured from a Chinese company `Build Your Dreams' (BYD). Data were collected by BMTC on the operation and maintenance of the bus. This new initiative, if rightly guided, could have a direct im...

  10. Testing programs for the Multimission Modular Spacecraft

    Science.gov (United States)

    Greenwell, T. J.

    1978-01-01

    The Multimission Modular Spacecraft (MMS) provides a standard spacecraft bus to a user for a variety of space missions ranging from near-earth to synchronous orbits. The present paper describes the philosophy behind the MMS module test program and discusses the implementation of the test program. It is concluded that the MMS module test program provides an effective and comprehensive customer buy-off at the subsystem contractor's plant, is an optimum approach for checkout of the subsystems prior to use for on-orbit servicing in the Shuttle Cargo Bay, and is a cost-effective technique for environmental testing.

  11. Exposure Assessment of Diesel Bus Emissions

    Directory of Open Access Journals (Sweden)

    Werner Hofmann

    2006-12-01

    Full Text Available The goal of this study was to measure ultrafine particle concentrations with diameters less than 1 μm emitted by diesel buses and to assess resulting human exposure levels. The study was conducted at the Woolloongabba Busway station in Brisbane, Australia in the winter months of 2002 during which temperature inversions frequently occurred. Most buses that utilize the station are fuelled by diesel, the exhaust of which contains a significant quantity of particle matter. Passengers waiting at the station are exposed to these particles emitted from the buses. During the course of this study, passenger census was conducted, based on video surveillance, yielding person-by-person waiting time data. Furthermore, a bus census revealed accurate information about the total number of diesel versus Compressed Natural Gas (CNG powered buses. Background (outside of the bus station and platform measurements of ultrafine particulate number size distributions were made to determine ambient aerosol concentrations. Particle number exposure concentration ranges from 10 and 40 to 60% of bus related exhaust fumes. This changes dramatically when considering the particle mass exposure concentration, where most passengers are exposed to about 50 to 80% of exhaust fumes. The obtained data can be very significant for comparison with similar work of this type because it is shown in previous studies that exhaust emissions causes cancer in laboratory animals. It was assumed that significant differences between platform and background distributions were due to bus emissions which, combined with passenger waiting times, yielded an estimate of passenger exposure to ultrafine particles from diesel buses. From an exposure point of view, the Busway station analyzed resembles a street canyon. Although the detected exhaust particle concentration at the outbound platform is found to be in the picogram range, exposure increases with the time passengers spend on the platform

  12. IMPACTS OF BUS STOP IMPROVEMENTS

    Science.gov (United States)

    2018-03-23

    Improving bus stops by providing shelters, seating, signage, and sidewalks is relatively inexpensive and popular among riders and local officials. Making such improvements, however, is not often a priority for U.S. transit providers because of compet...

  13. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Fourth Results Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2013-01-01

    SunLine Transit Agency, which provides public transit services to the Coachella Valley area of California, has demonstrated hydrogen and fuel cell bus technologies for more than 10 years. In May 2010, SunLine began demonstrating the advanced technology (AT) fuel cell bus with a hybrid electric propulsion system, fuel cell power system, and lithium-based hybrid batteries. This report describes operations at SunLine for the AT fuel cell bus and five compressed natural gas buses. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is working with SunLine to evaluate the bus in real-world service to document the results and help determine the progress toward technology readiness. NREL has previously published three reports documenting the operation of the fuel cell bus in service. This report provides a summary of the results with a focus on the bus operation from February 2012 through November 2012.

  14. MIL-STD-1553 dynamic bus controller/remote terminal hybrid set

    Science.gov (United States)

    Friedman, S. N.

    This paper describes the performance, physical and electrical requirements of a Dual Redundant BUS Interface Unit (BIU) acting as a BUS Controller Interface Unit (BCIU) or Remote Terminal Unit (RTU) between a Motorola 68000 VME BUS and MIL-STD-1553B Multiplex Data Bus. A discussion of how the BIU Hybrid set is programmed, and operates as a BCIU or RTU, will be included. This paper will review Dynamic Bus Control and other Mode Code capabilities. The BIU Hybrid Set interfaces to a 68000 Microprocessor with a VME Bus using programmed I/O transfers. This special interface will be discussed along with the internal Dual Access Memory (4K x 16) used to support the data exchanges between the CPU and the BIU Hybrid Set. The hybrid set's physical size and power requirements will be covered. This includes the present Double Eurocard the BIU function is presently being offered on.

  15. PEAC: A Power-Efficient Adaptive Computing Technology for Enabling Swarm of Small Spacecraft and Deployable Mini-Payloads

    Data.gov (United States)

    National Aeronautics and Space Administration — This task is to develop and demonstrate a path-to-flight and power-adaptive avionics technology PEAC (Power Efficient Adaptive Computing). PEAC will enable emerging...

  16. Superconducting link bus design for the accelerator project for upgrade of LHC

    International Nuclear Information System (INIS)

    Nobrega, F.; Brandt, J.; Cheban, S.; Feher, S.; Kaducak, M.; Kashikhin, V.; Peterson, T.

    2011-01-01

    The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as SC Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

  17. Bus systems in motor vehicles; Bussysteme im Kfz

    Energy Technology Data Exchange (ETDEWEB)

    Schule, Roland

    2008-07-01

    There is hardly any modern vehicle without a bus system. This interactive learning software explains why electric and electronic systems in motor vehicles should be linked and uses various bus types to illustrate the various alternatives, bus structures, and data types. The physical side of bus systems is gone into, the data structure is explained, and the various bus typologies are outlined. From the fundamentals of bus systems, the software proceeds to present the most important bus systems and their main properties. Subjects: Diagnosis bus, LIN bus, CAN bus, MOST bus, Bluetooth. The bus systems EIA-485, LVDS, D{sup 2}B, byteflight, and Flexray are briefly characterised. (orig.)

  18. A digital computer simulation and study of a direct-energy-transfer power-conditioning system

    Science.gov (United States)

    Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

    1975-01-01

    An investigation of the behavior of the power-conditioning system as a whole is a necessity to ensure the integrity of the aggregate system in the case of space applications. An approach for conducting such an investigation is considered. A description is given of the application of a general digital analog simulator program to the study of an aggregate power-conditioning system which is being developed for use on the International Ultraviolet Explorer spacecraft. The function of the direct energy transfer system studied involves a coupling of a solar array through a main distribution bus to the spacecraft electrical loads.

  19. Spacecraft operations

    CERN Document Server

    Sellmaier, Florian; Schmidhuber, Michael

    2015-01-01

    The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).

  20. Fuel cell bus operation, system investigation H2 bus

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The WP covers two tasks: - Prepartion of Technical Catalogue: In cooperation with ICIL, AR have compiled a technical catalogue, providing the impartial descriptions, both of existing technology and regulations, and the likely future developments of these, as to remedy the first problem faced by a potential hydrogen bus fleet operator viz the absence of an impartial description of the available vehicle and fuels systems together with the absence of a description of regulatory and safety factors which need consideration. - Fuel Cell Bus Operation - System Investigation H 2 Bus: The application of fuel cell electric generation systems to hybrid electrical buses or electrical busses without any storage system on board is considered. The task will cover safety and environmental aspects, a cost estimate and a market evaluation. (orig.)

  1. Preliminary Flight Results of the Microelectronics and Photonics Test Bed: NASA DR1773 Fiber Optic Data Bus Experiment

    Science.gov (United States)

    Jackson, George L.; LaBel, Kenneth A.; Marshall, Cheryl; Barth, Janet; Seidleck, Christina; Marshall, Paul

    1998-01-01

    NASA Goddard Spare Flight Center's (GSFC) Dual Rate 1773 (DR1773) Experiment on the Microelectronic and Photonic Test Bed (MPTB) has provided valuable information on the performance of the AS 1773 fiber optic data bus in the space radiation environment. Correlation of preliminary experiment data to ground based radiation test results show the AS 1773 bus is employable in future spacecraft applications requiring radiation tolerant communication links.

  2. Power Talk

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Popovski, Petar; Angjelichinoski, Marko

    2015-01-01

    We introduce a novel communication strategy for DC Micro Grids (MGs), termed power talk, in which the devices communicate by modulating the power levels in the DC bus. The information is transmitted by varying the parameters that the MG units use to control the level of the common bus voltage...

  3. Research and development of a phosphoric acid fuel cell/battery power source integrated in a test-bed bus. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-30

    This project, the research and development of a phosphoric acid fuel cell/battery power source integrated into test-bed buses, began as a multi-phase U.S. Department of Energy (DOE) project in 1989. Phase I had a goal of developing two competing half-scale (25 kW) brassboard phosphoric acid fuel cell systems. An air-cooled and a liquid-cooled fuel cell system were developed and tested to verify the concept of using a fuel cell and a battery in a hybrid configuration wherein the fuel cell supplies the average power required for operating the vehicle and a battery supplies the `surge` or excess power required for acceleration and hill-climbing. Work done in Phase I determined that the liquid-cooled system offered higher efficiency.

  4. A Study on Sunward-propagating Alfvénic Fluctuations with a Power-law Spectrum (SAFP) Observed by the WIND Spacecraft

    Science.gov (United States)

    Wang, X.; Wu, H.; Tu, C. Y.; Wang, L.; He, J.; Tian, H.

    2017-12-01

    Sunward-propagating Alfvénic fluctuations with a power-law spectrum (SAFP) have been recently reported to be a significant physical phenomenon in the solar wind. However, some characteristics of these SAFPs are still unknown. Here we develop a new method for identifying SAFPs. In this method, we can identify all SAFPs with any value of θRB (angle between the global magnetic field and the radial direction). We find 508 SAFPs using the WIND spacecraft observation from 1995 to 2014. We also find that SAFP occurs more frequently when θRB equals 90°. The spectral index with an average -1.77 changes continuously from -2.18 for the parallel to -1.71 for the perpendicular. SAFPs occur more at the maximum and tend to be observed in the slow solar wind especially at solar minimum. We also apply the new method to identify anti-sunward-propagating Alfvénic fluctuations with a power-law spectrum (AFP) for comparison. The number of SAFPs is much less than AFPs, and the cases with local bending account for about half of all observed cases. SAFPs have a preference for negative σc and ASFs for positive. The statistical results demonstrate that SAFP has a steeper and weaker power spectrum and present a weaker power anisotropy than that of AFP. These new results may reveal new insight into the physical mechanism of the SAFP generation.

  5. Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

    Science.gov (United States)

    Mengshoel, Ole Jakob; Poll, Scott; Kurtoglu, Tolga

    2009-01-01

    This CD contains files that support the talk (see CASI ID 20100021404). There are 24 models that relate to the ADAPT system and 1 Excel worksheet. In the paper an investigation into the use of Bayesian networks to construct large-scale diagnostic systems is described. The high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems are described in the talk. The data in the CD are the models of the 24 different power systems.

  6. Overview of Multi-DC-Bus Solutions for DC Microgrids

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco

    2013-01-01

    DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....

  7. San Antonio's 1983 Bus Passenger Survey

    Science.gov (United States)

    1983-10-01

    Many transit operators routinely collect ridership data in order to provide a : basis for the planning of bus services. Often a survey is conducted of bus : riders to determine their riding habits, their views about the quality of : current service, ...

  8. Gravity Probe B spacecraft description

    International Nuclear Information System (INIS)

    Bennett, Norman R; Burns, Kevin; Katz, Russell; Kirschenbaum, Jon; Mason, Gary; Shehata, Shawky

    2015-01-01

    The Gravity Probe B spacecraft, developed, integrated, and tested by Lockheed Missiles and Space Company and later Lockheed Martin Corporation, consisted of structures, mechanisms, command and data handling, attitude and translation control, electrical power, thermal control, flight software, and communications. When integrated with the payload elements, the integrated system became the space vehicle. Key requirements shaping the design of the spacecraft were: (1) the tight mission timeline (17 months, 9 days of on-orbit operation), (2) precise attitude and translational control, (3) thermal protection of science hardware, (4) minimizing aerodynamic, magnetic, and eddy current effects, and (5) the need to provide a robust, low risk spacecraft. The spacecraft met all mission requirements, as demonstrated by dewar lifetime meeting specification, positive power and thermal margins, precision attitude control and drag-free performance, reliable communications, and the collection of more than 97% of the available science data. (paper)

  9. Preliminary thermal design of the COLD-SAT spacecraft

    Science.gov (United States)

    Arif, Hugh

    1991-01-01

    The COLD-SAT free-flying spacecraft was to perform experiments with LH2 in the cryogenic fluid management technologies of storage, supply and transfer in reduced gravity. The Phase A preliminary design of the Thermal Control Subsystem (TCS) for the spacecraft exterior and interior surfaces and components of the bus subsystems is described. The TCS was composed of passive elements which were augmented with heaters. Trade studies to minimize the parasitic heat leakage into the cryogen storage tanks are described. Selection procedure for the thermally optimum on-orbit spacecraft attitude was defined. TRASYS-2 and SINDA'85 verification analysis was performed on the design and the results are presented.

  10. Real life testing of a Hybrid PEM Fuel Cell Bus

    Science.gov (United States)

    Folkesson, Anders; Andersson, Christian; Alvfors, Per; Alaküla, Mats; Overgaard, Lars

    Fuel cells produce low quantities of local emissions, if any, and are therefore one of the most promising alternatives to internal combustion engines as the main power source in future vehicles. It is likely that urban buses will be among the first commercial applications for fuel cells in vehicles. This is due to the fact that urban buses are highly visible for the public, they contribute significantly to air pollution in urban areas, they have small limitations in weight and volume and fuelling is handled via a centralised infrastructure. Results and experiences from real life measurements of energy flows in a Scania Hybrid PEM Fuel Cell Concept Bus are presented in this paper. The tests consist of measurements during several standard duty cycles. The efficiency of the fuel cell system and of the complete vehicle are presented and discussed. The net efficiency of the fuel cell system was approximately 40% and the fuel consumption of the concept bus is between 42 and 48% lower compared to a standard Scania bus. Energy recovery by regenerative braking saves up 28% energy. Bus subsystems such as the pneumatic system for door opening, suspension and brakes, the hydraulic power steering, the 24 V grid, the water pump and the cooling fans consume approximately 7% of the energy in the fuel input or 17% of the net power output from the fuel cell system. The bus was built by a number of companies in a project partly financed by the European Commission's Joule programme. The comprehensive testing is partly financed by the Swedish programme "Den Gröna Bilen" (The Green Car). A 50 kW el fuel cell system is the power source and a high voltage battery pack works as an energy buffer and power booster. The fuel, compressed hydrogen, is stored in two high-pressure stainless steel vessels mounted on the roof of the bus. The bus has a series hybrid electric driveline with wheel hub motors with a maximum power of 100 kW. Hybrid Fuel Cell Buses have a big potential, but there are

  11. School Bus Accidents and Driver Age.

    Science.gov (United States)

    McMichael, Judith

    The study examines the rates and types of school bus accidents according to the age of the school bus driver. Accident rates in North Carolina for the school year 1971-72 were analyzed using three sources of data: accident reports, driver and mileage data, and questionnaires administered to a sample of school bus drivers. Data were obtained on…

  12. Optimizing Tailored Bus Bridging Paths

    NARCIS (Netherlands)

    Gu, Wei; Yu, Jie; Ji, Yuxiong; van der Gun, J.P.T.; Pel, A.J.; Zhang, H. Michael; van Arem, B.

    2017-01-01

    Metro disruptions due to unexpected events reduce transit system reliability, resulting in significant productivity loss and long passenger delays. Bus bridging strategy is often used to connect stations affected by metro disruptions such that passengers could continue their journey. The literature

  13. Bus transport in Greater Manchester

    DEFF Research Database (Denmark)

    Sørensen, Claus Hedegaard; Gudmundsson, Henrik

    component regards the organisation of public bus transport at the local level. This involves the deregulation and privatisation reforms introduced by the Conservative Government from 1986 onwards, as well as the ‘partnerships’ and other new instruments introduced by the Labour Government in the Transport...

  14. Pybus - A Python Software Bus

    International Nuclear Information System (INIS)

    Lavrijsen, Wim T.L.P.

    2004-01-01

    A software bus, just like its hardware equivalent, allows for the discovery, installation, configuration, loading, unloading, and run-time replacement of software components, as well as channeling of inter-component communication. Python, a popular open-source programming language, encourages a modular design on software written in it, but it offers little or no component functionality. However, the language and its interpreter provide sufficient hooks to implement a thin, integral layer of component support. This functionality can be presented to the developer in the form of a module, making it very easy to use. This paper describes a Pythonmodule, PyBus, with which the concept of a ''software bus'' can be realized in Python. It demonstrates, within the context of the ATLAS software framework Athena, how PyBus can be used for the installation and (run-time) configuration of software, not necessarily Python modules, from a Python application in a way that is transparent to the end-user

  15. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Third Evaluation Report and Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2010-01-01

    This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The prototype fuel cell bus was manufactured by Van Hool and ISE Corp. and features an electric hybrid drive system with a UTC Power PureMotion 120 Fuel Cell Power System and ZEBRA batteries for energy storage. The fuel cell bus started operation in April 2007, and evaluation results through October 2009 are provided in this report.

  16. Optimum Dispatch of Hybrid Solar Thermal (HSTP Electric Power Plant Using Non-Smooth Cost Function and Emission Function for IEEE-30 Bus System

    Directory of Open Access Journals (Sweden)

    Saroj Kumar Dash

    2016-07-01

    Full Text Available The basic objective of economic load dispatch (ELD is to optimize the total fuel cost of hybrid solar thermal electric power plant (HSTP. In ELD problems the cost function for each generator has been approximated by a single quadratic cost equation. As cost of coal increases, it becomes even more important have a good model for the production cost of each generator for the solar thermal hybrid system. A more accurate formulation is obtained for the ELD problem by expressing the generation cost function as a piece wise quadratic cost function. However, the solution methods for ELD problem with piece wise quadratic cost function requires much complicated algorithms such as the hierarchical structure approach along with evolutionary computations (ECs. A test system comprising of 10 units with 29 different fuel [7] cost equations is considered in this paper. The applied genetic algorithm method will provide optimal solution for the given load demand.

  17. Power line harmonic radiation observed by the DEMETER spacecraft at 50/60Hz and low harmonics

    Czech Academy of Sciences Publication Activity Database

    Němec, F.; Parrot, M.; Santolík, Ondřej

    2015-01-01

    Roč. 120, č. 10 (2015), s. 8954-8967 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GA14-31899S; GA MŠk LH12231 Institutional support: RVO:68378289 Keywords : PLHR * power line harmonic radiation * DEMETER Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2015JA021682/full

  18. Analysis of robustness of urban bus network

    Science.gov (United States)

    Tao, Ren; Yi-Fan, Wang; Miao-Miao, Liu; Yan-Jie, Xu

    2016-02-01

    In this paper, the invulnerability and cascade failures are discussed for the urban bus network. Firstly, three static models(bus stop network, bus transfer network, and bus line network) are used to analyse the structure and invulnerability of urban bus network in order to understand the features of bus network comprehensively. Secondly, a new way is proposed to study the invulnerability of urban bus network by modelling two layered networks, i.e., the bus stop-line network and the bus line-transfer network and then the interactions between different models are analysed. Finally, by modelling a new layered network which can reflect the dynamic passenger flows, the cascade failures are discussed. Then a new load redistribution method is proposed to study the robustness of dynamic traffic. In this paper, the bus network of Shenyang City which is one of the biggest cities in China, is taken as a simulation example. In addition, some suggestions are given to improve the urban bus network and provide emergency strategies when traffic congestion occurs according to the numerical simulation results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61473073, 61374178, 61104074, and 61203329), the Fundamental Research Funds for the Central Universities (Grant Nos. N130417006, L1517004), and the Program for Liaoning Excellent Talents in University (Grant No. LJQ2014028).

  19. Multi-Mission Power Analysis Tool (MMPAT) Version 3

    Science.gov (United States)

    Wood, Eric G.; Chang, George W.; Chen, Fannie C.

    2012-01-01

    The Multi-Mission Power Analysis Tool (MMPAT) simulates a spacecraft power subsystem including the power source (solar array and/or radioisotope thermoelectric generator), bus-voltage control, secondary battery (lithium-ion or nickel-hydrogen), thermostatic heaters, and power-consuming equipment. It handles multiple mission types including heliocentric orbiters, planetary orbiters, and surface operations. Being parametrically driven along with its user-programmable features can reduce or even eliminate any need for software modifications when configuring it for a particular spacecraft. It provides multiple levels of fidelity, thereby fulfilling the vast majority of a project s power simulation needs throughout the lifecycle. It can operate in a stand-alone mode with a graphical user interface, in batch mode, or as a library linked with other tools. This software can simulate all major aspects of a spacecraft power subsystem. It is parametrically driven to reduce or eliminate the need for a programmer. Added flexibility is provided through user-designed state models and table-driven parameters. MMPAT is designed to be used by a variety of users, such as power subsystem engineers for sizing power subsystem components; mission planners for adjusting mission scenarios using power profiles generated by the model; system engineers for performing system- level trade studies using the results of the model during the early design phases of a spacecraft; and operations personnel for high-fidelity modeling of the essential power aspect of the planning picture.

  20. Spacecraft Thermal Management

    Science.gov (United States)

    Hurlbert, Kathryn Miller

    2009-01-01

    In the 21st century, the National Aeronautics and Space Administration (NASA), the Russian Federal Space Agency, the National Space Agency of Ukraine, the China National Space Administration, and many other organizations representing spacefaring nations shall continue or newly implement robust space programs. Additionally, business corporations are pursuing commercialization of space for enabling space tourism and capital business ventures. Future space missions are likely to include orbiting satellites, orbiting platforms, space stations, interplanetary vehicles, planetary surface missions, and planetary research probes. Many of these missions will include humans to conduct research for scientific and terrestrial benefits and for space tourism, and this century will therefore establish a permanent human presence beyond Earth s confines. Other missions will not include humans, but will be autonomous (e.g., satellites, robotic exploration), and will also serve to support the goals of exploring space and providing benefits to Earth s populace. This section focuses on thermal management systems for human space exploration, although the guiding principles can be applied to unmanned space vehicles as well. All spacecraft require a thermal management system to maintain a tolerable thermal environment for the spacecraft crew and/or equipment. The requirements for human rating and the specified controlled temperature range (approximately 275 K - 310 K) for crewed spacecraft are unique, and key design criteria stem from overall vehicle and operational/programatic considerations. These criteria include high reliability, low mass, minimal power requirements, low development and operational costs, and high confidence for mission success and safety. This section describes the four major subsystems for crewed spacecraft thermal management systems, and design considerations for each. Additionally, some examples of specialized or advanced thermal system technologies are presented

  1. 30-kW SEP Spacecraft as Secondary Payloads for Low-Cost Deep Space Science Missions

    Science.gov (United States)

    Brophy, John R.; Larson, Tim

    2013-01-01

    The Solar Array System contracts awarded by NASA's Space Technology Mission Directorate are developing solar arrays in the 30 kW to 50 kW power range (beginning of life at 1 AU) that have significantly higher specific powers (W/kg) and much smaller stowed volumes than conventional rigid-panel arrays. The successful development of these solar array technologies has the potential to enable new types of solar electric propulsion (SEP) vehicles and missions. This paper describes a 30-kW electric propulsion vehicle built into an EELV Secondary Payload Adapter (ESPA) ring. The system uses an ESPA ring as the primary structure and packages two 15-kW Megaflex solar array wings, two 14-kW Hall thrusters, a hydrazine Reaction Control Subsystem (RCS), 220 kg of xenon, 26 kg of hydrazine, and an avionics module that contains all of the rest of the spacecraft bus functions and the instrument suite. Direct-drive is used to maximize the propulsion subsystem efficiency and minimize the resulting waste heat and required radiator area. This is critical for packaging a high-power spacecraft into a very small volume. The fully-margined system dry mass would be approximately 1120 kg. This is not a small dry mass for a Discovery-class spacecraft, for example, the Dawn spacecraft dry mass was only about 750 kg. But the Dawn electric propulsion subsystem could process a maximum input power of 2.5 kW, and this spacecraft would process 28 kW, an increase of more than a factor of ten. With direct-drive the specific impulse would be limited to about 2,000 s assuming a nominal solar array output voltage of 300 V. The resulting spacecraft would have a beginning of life acceleration that is more than an order of magnitude greater than the Dawn spacecraft. Since the spacecraft would be built into an ESPA ring it could be launched as a secondary payload to a geosynchronous transfer orbit significantly reducing the launch costs for a planetary spacecraft. The SEP system would perform the escape

  2. Avionic Data Bus Integration Technology

    Science.gov (United States)

    1991-12-01

    address the hardware-software interaction between a digital data bus and an avionic system. Very Large Scale Integration (VLSI) ICs and multiversion ...the SCP. In 1984, the Sperry Corporation developed a fault tolerant system which employed multiversion programming, voting, and monitoring for error... MULTIVERSION PROGRAMMING. N-version programming. 226 N-VERSION PROGRAMMING. The independent coding of a number, N, of redundant computer programs that

  3. New TPG bus route 28

    CERN Multimedia

    2003-01-01

    Geneva's Public Transport services (TPG) have recently inaugurated a new bus line 28, connecting the La Tour Hospital in Meyrin to the international organisations in Geneva, via the airport. All signs associated with this route will be yellow in colour. Timetables and route details can be found at http://www.tpg.ch. Relations with the Host States Service http://www.cern.ch/relations/ Tel. 72848

  4. HEV Test Bench Based on CAN Bus Sensor Communication

    Directory of Open Access Journals (Sweden)

    Shupeng ZHAO

    2014-02-01

    Full Text Available The HEV test bench based on Controller Area Network bus was studied and developed. Control system of HEV power test bench used the CAN bus technology. The application of CAN bus technology on control system development has opened up a new research direction for domestic automobile experimental platform. The HEV power control system development work was completed, including power master controller, electric throttle controller, driving simulation platform, CAN2.0 B communication protocol procedures for formulation, CAN communication monitoring system, the simulation model based on MATLAB code automatic generation technology research, etc. Maximum absorption power of the test bench is 90 kW, the test bench top speed is 6000 r/min, the CAN communication data baud rate is 10~500 k, the conventional electric measurement parameter part precision satisfies the requirement of development of HEV. On the HEV test bench the result of regenerative braking experiment shows that the result got by the test bench was closer to the results got by outdoor road test. And the fuel consumption experiment test results show that the HEV fuel consumption and the charge-discharge character are in linear relationship. The establishment of the test platform for the evaluation of the development of hybrid electric vehicle and power provides physical simulation and test platform.

  5. Status of the FASTBUS standard data bus

    International Nuclear Information System (INIS)

    Larsen, R.S.

    1980-11-01

    FASTBUS is a new laboratory standard data bus intended for use in experimental data acquisition and control. The development of FASTBUS began with a feasibility study in 1976, and is presently at the development prototyping stage. The principal aims of the standard are to provide a factor of ten or more improvement in speed of data transfers over present systems, as well as to provide an architecture for systems containing multiple processors. Developmental prototypes now in progress include crates, backplanes, cooling devices, power supplies, test and diagnostic modules, and user modules. A sizeable software development effort is also underway. Several experiments have made commitments to use FASTBUS. A review of current work and potential applications is given. 10 figures

  6. Spacecraft radiator systems

    Science.gov (United States)

    Anderson, Grant A. (Inventor)

    2012-01-01

    A spacecraft radiator system designed to provide structural support to the spacecraft. Structural support is provided by the geometric "crescent" form of the panels of the spacecraft radiator. This integration of radiator and structural support provides spacecraft with a semi-monocoque design.

  7. Aerodynamic study of state transport bus using computational fluid dynamics

    Science.gov (United States)

    Kanekar, Siddhesh; Thakre, Prashant; Rajkumar, E.

    2017-11-01

    The main purpose of this study was to develop the aerodynamic study of a Maharashtra state road transport bus. The rising fuel price and strict government regulations makes the road transport uneconomical now days. With the objective of increasing fuel efficiency and reducing the emission of harmful exhaust gases. It has been proven experimentally that vehicle consumes almost 40% of the available useful engine power to overcome the drag resistance. This provides us a huge scope to study the influence of aerodynamic drag. The initial of the project was to identify the drag coefficient of the existing ordinary type model called “Parivartan” from ANSYS fluent. After preliminary analysis of the existing model corresponding changes are made in such a way that their implementation should be possible at workshop level. The simulation of the air flow over the bus was performed in two steps: design on SolidWorks CAD and ANSYS (FLUENT) is used as a virtual analysis tool to estimate the drag coefficient of the bus. We have used the turbulence models k-ε Realizable having a better approximation of the actual result. Around 28% improvement in the drag coefficient is achieved by CFD driven changes in the bus design. Coefficient of drag is improved by 28% and fuel efficiency increased by 20% by CFD driven changes.

  8. National fuel cell bus program : proterra fuel cell hybrid bus report, Columbia demonstration.

    Science.gov (United States)

    2011-10-01

    This report summarizes the experience and early results from a fuel cell bus demonstration funded by the Federal Transit Administration (FTA) under the National Fuel Cell Bus Program. A team led by the Center for Transportation and the Environment an...

  9. Bus Route Design with a Bayesian Network Analysis of Bus Service Revenues

    OpenAIRE

    Liu, Yi; Jia, Yuanhua; Feng, Xuesong; Wu, Jiang

    2018-01-01

    A Bayesian network is used to estimate revenues of bus services in consideration of the effect of bus travel demands, passenger transport distances, and so on. In this research, the area X in Beijing has been selected as the study area because of its relatively high bus travel demand and, on the contrary, unsatisfactory bus services. It is suggested that the proposed Bayesian network approach is able to rationally predict the probabilities of different revenues of various route services, from...

  10. Foundation field bus in the Spanish nuclear sector

    International Nuclear Information System (INIS)

    Saez de Montagut Revenga, G.

    2013-01-01

    This paper deals with the modification made in power plants nuclear ASCO 1 and 2 in which scans is the level Control system of Heaters to implementing an Ovation system, as well as the standard Foundation Field bus for field communications. This digitalisation has required a detailed study of the implications on security that could have the centralization of control loops in main feedwater system.

  11. Multi drop bus controller for IBM PC/AT

    International Nuclear Information System (INIS)

    Bardik, Yu.I.; Kalistratov, E.N.; Matyushin, A.A.; Obukhov, G.A.; Trofimov, N.N.

    1993-01-01

    The module PC-AT-PBC gives a possibility to create a working place based on the computer IBM PC/AT for testing of hardware which is compatible with the multi drop bus. The KP1830BE31 micro program change turns the module into timing generator for power supply controllers of the UNK correction system. The structure of the module, functional parts, library functions and two application programs have been described. 4 refs., 9 figs

  12. Optimal bus temperature for thermal comfort during a cool day.

    Science.gov (United States)

    Velt, K B; Daanen, H A M

    2017-07-01

    A challenge for electric buses is to minimize heating and cooling power to maximally extend the driving range, but still provide sufficient thermal comfort for the driver and passengers. Therefore, we investigated the thermal sensation (TS) and thermal comfort (TC) of passengers in buses during a cool day (temperature 13.4 ± 0.5 °C, relative humidity (RH) 60 ± 5.8%) typical for the Dutch temperate maritime climate. 28 Males and 72 females rated TS and TC and gave information on age, stature, body weight and worn garments. The temperature in the bus of 22.5 ± 1.1 °C and RH of 59.9 ± 5.8% corresponded to a slightly warm feeling (TS = 0.85 ± 1.06) and TC of 0.39 ± 0.65. TS related significantly to bus temperature, clothing insulation and age. Linear regression based on these parameters showed that the temperature in the bus corresponding to TC = 0 and TS = 0 would have been 20.9 ± 0.6 °C. In conclusion, a 1.6 °C lower bus temperature during the investigated cool day probably would have led to less thermal discomfort and energy savings of electrical busses. The methodology to relate climatic measurements to subjective assessments is currently employed in a wider climatic range and may prove to be useful to find a better balance between thermal comfort and energy savings of the bus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Road safety issues for bus transport management.

    Science.gov (United States)

    Cafiso, Salvatore; Di Graziano, Alessandro; Pappalardo, Giuseppina

    2013-11-01

    Because of the low percentage of crashes involving buses and the assumption that public transport improves road safety by reducing vehicular traffic, public interest in bus safety is not as great as that in the safety of other types of vehicles. It is possible that less attention is paid to the significance of crashes involving buses because the safety level of bus systems is considered to be adequate. The purpose of this study was to evaluate the knowledge and perceptions of bus managers with respect to safety issues and the potential effectiveness of various technologies in achieving higher safety standards. Bus managers were asked to give their opinions on safety issues related to drivers (training, skills, performance evaluation and behaviour), vehicles (maintenance and advanced devices) and roads (road and traffic safety issues) in response to a research survey. Kendall's algorithm was used to evaluate the level of concordance. The results showed that the majority of the proposed items were considered to have great potential for improving bus safety. The data indicated that in the experience of the participants, passenger unloading and pedestrians crossing near bus stops are the most dangerous actions with respect to vulnerable users. The final results of the investigation showed that start inhibition, automatic door opening, and the materials and internal architecture of buses were considered the items most strongly related to bus passenger safety. Brake assistance and vehicle monitoring systems were also considered to be very effective. With the exception of driver assistance systems for passenger and pedestrian safety, the perceptions of the importance of other driver assistance systems for vehicle monitoring and bus safety were not unanimous among the bus company managers who participated in this survey. The study results showed that the introduction of new technologies is perceived as an important factor in improving bus safety, but a better understanding

  14. American fuel cell bus project : first analysis report.

    Science.gov (United States)

    2013-06-01

    This report summarizes the experience and early results from the American Fuel Cell Bus Project, a fuel cell electric bus demonstration : funded by the Federal Transit Administration (FTA) under the National Fuel Cell Bus Program. A team led by CALST...

  15. Fuel Cell Electric Bus Evaluations | Hydrogen and Fuel Cells | NREL

    Science.gov (United States)

    Bus Evaluations Fuel Cell Electric Bus Evaluations NREL's technology validation team evaluates fuel cell electric buses (FCEBs) to provide comprehensive, unbiased evaluation results of fuel cell bus early transportation applications for fuel cell technology. Buses operate in congested areas where

  16. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.

    2014-11-01

    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  17. Spacecraft System Integration and Test: SSTI Lewis critical design audit

    Science.gov (United States)

    Brooks, R. P.; Cha, K. K.

    1995-01-01

    The Critical Design Audit package is the final detailed design package which provides a comprehensive description of the SSTI mission. This package includes the program overview, the system requirements, the science and applications activities, the ground segment development, the assembly, integration and test description, the payload and technology demonstrations, and the spacecraft bus subsystems. Publication and presentation of this document marks the final requirements and design freeze for SSTI.

  18. Optimization of transit bus fleet's life cycle assessment impacts with alternative fuel options

    International Nuclear Information System (INIS)

    Ercan, Tolga; Zhao, Yang; Tatari, Omer; Pazour, Jennifer A.

    2015-01-01

    Public transportation is one of the most promising transportation modes to reduce the environmental emissions of the transportation sector in the U.S. In order to mitigate the environmental impacts brought by the transit bus system, new energy buses are introduced into the vehicle market. The goal of this study is to find an optimal bus fleet combination for different driving conditions to minimize life cycle cost, greenhouse gas emissions, and conventional air pollutant emission impacts. For this purpose, a Multi-Objective Linear Programming approach is used to select the optimum bus fleet combinations. Given different weight scenarios, this method could effectively provide solutions for decision makers with various budget constraints or emission reduction requirements. The results indicate that in heavily congested driving cycles such as the Manhattan area, the battery electric bus is the dominant vehicle type, while the hybrid bus has more balanced performances in most scenarios because of its lower initial investment comparing to battery electric buses. Petroleum powered buses have seldom been selected by the model. The trade-off analysis shows that the overall greenhouse gas impact performance is sensitive to the life cycle cost after certain points, which could provide valuable information for the bus fleet combination planning. - Highlights: • Hybrid-Life Cycle Assessment analysis approach for transit bus operations. • Optimizing the economic and sustainability impacts of transit bus fleet operation. • CO 2 emissions and other air pollutants related health and environmental damage cost. • Trade-offs between CO 2 emissions and cost of transit bus fleet operation.

  19. Mastering NServiceBus and persistence

    CERN Document Server

    Helton, Rich

    2014-01-01

    This book is intended for developers, designers, and architects alike who wish to build C# NServiceBus enterprise architectures and learn how ESB persists data and messages to help them attain their goals. No prior knowledge of persistence in NServiceBus is required.

  20. Digital processing data communication systems (bus systems)

    International Nuclear Information System (INIS)

    Fleck, K.

    1980-01-01

    After an introduction to the technology of digital processing data communication systems there are the following chapters: digital communication of processing data in automation technology, the technology of biserial communication, the implementaiton of a bus system, the data transmission of the TDC-2000 system of Honeywell's and the process bus CS 275 in the automation system TELEPERM M of Siemens AG. (WB) [de

  1. NREL Showcases Hydrogen Internal Combustion Engine Bus, Helps DOE Set Standards for Outreach (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-11-01

    This fact sheet describes the National Renewable Energy Laboratory's (NREL's) accomplishments in showcasing a Ford hydrogen-powered internal combustion engine (H2ICE) bus at The Taste of Colorado festival in Denver. NREL started using its U.S. Department of Energy-funded H2ICE bus in May 2010 as the primary shuttle vehicle for VIP visitors, members of the media, and new employees. In September 2010, NREL featured the bus at The Taste of Colorado. This was the first major outreach event for the bus. NREL's educational brochure, vehicle wrap designs, and outreach efforts serve as a model for other organizations with DOE-funded H2ICE buses. Work was performed by the Hydrogen Education Group and Market Transformation Group in the Hydrogen Technologies and Systems Center.

  2. Characterizing the range of children's air pollutant exposure during school bus commutes.

    Science.gov (United States)

    Sabin, Lisa D; Behrentz, Eduardo; Winer, Arthur M; Jeong, Seong; Fitz, Dennis R; Pankratz, David V; Colome, Steven D; Fruin, Scott A

    2005-09-01

    Real-time and integrated measurements of gaseous and particulate pollutants were conducted inside five conventional diesel school buses, a diesel bus with a particulate trap, and a bus powered by compressed natural gas (CNG) to determine the range of children's exposures during school bus commutes and conditions leading to high exposures. Measurements were made during 24 morning and afternoon commutes on two Los Angeles Unified School District bus routes from South to West Los Angeles, with seven additional runs on a rural/suburban route, and three runs to test the effect of window position. For these commutes, the mean concentrations of diesel vehicle-related pollutants ranged from 0.9 to 19 microg/m(3) for black carbon, 23 to 400 ng/m(3) for particle-bound polycyclic aromatic hydrocarbon (PB-PAH), and 64 to 220 microg/m(3) for NO(2). Concentrations of benzene and formaldehyde ranged from 0.1 to 11 microg/m(3) and 0.3 to 5 microg/m(3), respectively. The highest real-time concentrations of black carbon, PB-PAH and NO(2) inside the buses were 52 microg/m(3), 2000 ng/m(3), and 370 microg/m(3), respectively. These pollutants were significantly higher inside conventional diesel buses compared to the CNG bus, although formaldehyde concentrations were higher inside the CNG bus. Mean black carbon, PB-PAH, benzene and formaldehyde concentrations were higher when the windows were closed, compared with partially open, in part, due to intrusion of the bus's own exhaust into the bus cabin, as demonstrated through the use of a tracer gas added to each bus's exhaust. These same pollutants tended to be higher on urban routes compared to the rural/suburban route, and substantially higher inside the bus cabins compared to ambient measurements. Mean concentrations of pollutants with substantial secondary formation, such as PM(2.5), showed smaller differences between open and closed window conditions and between bus routes. Type of bus, traffic congestion levels, and encounters with

  3. A fuel cell city bus with three drivetrain configurations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junping [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Yong [School of Automobile and Transporting Engineering, Liaoning Institute of Technology, Jinzhou, Liaoning 121001 (China); Chen, Quanshi [State Key Laboratory of Automobile Safety and Energy Conservation, Tsinghua University, Beijing 100084 (China)

    2006-09-22

    Three fuel cell city buses of the energy hybrid- and power hybrid-type were re-engineered with three types of drivetrain configuration to optimize the structure and improve the performance. The energy distribution, hydrogen consumption, state of charge (SOC) and the power variation rate were analyzed when different drivetrain configurations and parameters were used. When powered only by a fuel cell, the bus cannot recover the energy through regenerative braking. The variation of the fuel cell power is large and frequent, which is not good for the fuel cell. When the fuel cell is linked to a battery pack in parallel, the bus can recover the energy through regenerative braking. The energy distribution is determined by the parameters of the fuel cell and the battery pack in the design stage to reduce the power variation rate of the fuel cell. When the fuel cell and DC/DC converter connected in series links the battery pack in parallel, energy can be recovered and the energy distribution can be adjusted online. The power variation rate of both the fuel cell and the battery pack are reduced. (author)

  4. Bus Route Design with a Bayesian Network Analysis of Bus Service Revenues

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2018-01-01

    Full Text Available A Bayesian network is used to estimate revenues of bus services in consideration of the effect of bus travel demands, passenger transport distances, and so on. In this research, the area X in Beijing has been selected as the study area because of its relatively high bus travel demand and, on the contrary, unsatisfactory bus services. It is suggested that the proposed Bayesian network approach is able to rationally predict the probabilities of different revenues of various route services, from the perspectives of both satisfying passenger demand and decreasing bus operation cost. This way, the existing bus routes in the studied area can be optimized for their most probable high revenues.

  5. Bus and Tag Terminators for IBM system/360

    CERN Multimedia

    Control units were connected to the channels with "Bus and Tag" cable pairs. The bus cables carried the address and data information and the tag cables identified what data was on the bus. There were three general types of bus-and-tag cables produced by IBM.

  6. PCISIM - A Simulation Tool for PCI Bus Based Systems

    DEFF Research Database (Denmark)

    Sharp, Robin

    1999-01-01

    This document describes a PCI bus simulator for use in evaluating the feasibility of system designs based on this bus.......This document describes a PCI bus simulator for use in evaluating the feasibility of system designs based on this bus....

  7. Safety evaluation of a hydrogen fueled transit bus

    Energy Technology Data Exchange (ETDEWEB)

    Coutts, D.A.; Thomas, J.K.; Hovis, G.L.; Wu, T.T. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1997-12-31

    Hydrogen fueled vehicle demonstration projects must satisfy management and regulator safety expectations. This is often accomplished using hazard and safety analyses. Such an analysis has been completed to evaluate the safety of the H2Fuel bus to be operated in Augusta, Georgia. The evaluation methods and criteria used reflect the Department of Energy`s graded approach for qualifying and documenting nuclear and chemical facility safety. The work focused on the storage and distribution of hydrogen as the bus motor fuel with emphases on the technical and operational aspects of using metal hydride beds to store hydrogen. The safety evaluation demonstrated that the operation of the H2Fuel bus represents a moderate risk. This is the same risk level determined for operation of conventionally powered transit buses in the United States. By the same criteria, private passenger automobile travel in the United States is considered a high risk. The evaluation also identified several design and operational modifications that resulted in improved safety, operability, and reliability. The hazard assessment methodology used in this project has widespread applicability to other innovative operations and systems, and the techniques can serve as a template for other similar projects.

  8. Bavarian liquid hydrogen bus demonstration project - safety, licensing and acceptability aspects

    Energy Technology Data Exchange (ETDEWEB)

    Wurster, R.; Knorr, H.; Pruemm, W.

    1999-07-01

    A regular 12 m city bus of the MAN SL 202 type with an internal combustion engine adapted to hydrogen operation and auxiliary gasoline operation was demonstrated in the Bavarian cities of Erlangen and Munich between April 1996 and August 1998. Three bus operators, Erlanger Stadtwerke, Stadtwerke Muenchen and Autobus Oberbayern were testing the bus in three different operating schemes. In order to be able to perform this worldwide first public demonstration of a liquid hydrogen (LH{sub 2}) city bus in regular service, several requirements with respect to safety, licensing, training and acceptability had to be fulfilled. These activities were focusing mainly on the hydrogen specific issues such as (a) integration of onboard LH{sub 2} storage vessels, piping and instrumentation, (b) implementation of storage and refueling infrastructure in the operators' yards, (c) adaptation of the maintenance garages, (d) training of operating and maintenance personnel. During phase II of the demonstration activity a poll was performed on passengers traveling onboard the hydrogen-powered city bus in order to determined the level of acceptance among the users of the bus. The bus was designed and manufactured by MAN Nutzfahrzeuge Aktiengesellschaft. The cryogenic fuel storage and the refueling equipment were designed and manufactured by Linde AG. The realization of the hardware was financially supported by the European Commission (EC) within the Euro-Quebec Hydro-Hydrogen Pilot Project. The demonstration phase was financially supported by EC and the Bavarian State Government. Ludwig-Boelkow-Systemtechnik performed project monitoring for both funding organizations. The presentation will summarize the most important results of this demonstration phase and will address the measures undertaken in order to get the bus, the refueling infrastructure and the maintenance and operating procedures approved by the relevant authorities.

  9. Large truck and bus crash facts, 2010.

    Science.gov (United States)

    2012-09-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and : property damage only crashes involving large trucks and buses in 2010. Selected crash statistics on passenger : vehicles are also presen...

  10. Large truck and bus crash facts, 2012.

    Science.gov (United States)

    2014-06-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and property damage only crashes involving large trucks and buses in 2012. Selected crash statistics on passenger vehicles are also presented ...

  11. Large truck and bus crash facts, 2013.

    Science.gov (United States)

    2015-04-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and property damage only crashes involving large trucks and buses in 2013. Selected crash statistics on passenger vehicles are also presented ...

  12. Large truck and bus crash facts, 2009.

    Science.gov (United States)

    2011-10-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and : property damage only crashes involving large trucks and buses in 2009. Selected crash statistics on passenger : vehicles are also presen...

  13. Large truck and bus crash facts, 2011.

    Science.gov (United States)

    2013-10-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and : property damage only crashes involving large trucks and buses in 2011. Selected crash statistics on passenger : vehicles are also presen...

  14. Passenger bus industry weather information application.

    Science.gov (United States)

    2011-03-21

    Adverse weather significantly affects the United States national transportation system, including commercial companies : that rely on highways to support their enterprises. The Passenger Bus (Motorcoach) Industry (PBI) is one such affected : user who...

  15. Understanding & modeling bus transit driver availability.

    Science.gov (United States)

    2014-07-01

    Bus transit agencies are required to hire extraboard (i.e. back-up) operators to account for unexpected absences. Incorrect sizing of extra driver workforce is problematic for a number of reasons. Overestimating the appropriate number of extraboard o...

  16. Bicycle-bus conflict area study.

    Science.gov (United States)

    2009-11-01

    Increasing bicycle use and bus ridership are both desirable policy goals : from a sustainability standpoint, but on city streets these two modes of : transport are often in conflict. While occupying opposite ends of the size : and weight spectrum, th...

  17. THE FUTURE OF SPACECRAFT NUCLEAR PROPULSION

    OpenAIRE

    Jansen, Frank

    2014-01-01

    This paper summarizes the advantages of space nuclear power and propulsion systems. It describes the actual status of international power level dependent spacecraft nuclear propulsion missions, especially the high power EU-Russian MEGAHIT study including the Russian Megawatt-Class Nuclear Power Propulsion System, the NASA GRC project and the low and medium power EU DiPoP study. Space nuclear propulsion based mission scenarios of these studies are sketched as well.

  18. TMS communications software. Volume 2: Bus interface unit

    Science.gov (United States)

    Gregor, P. J.

    1979-01-01

    A data bus communication system to support the space shuttle's Trend Monitoring System (TMS) and to provide a basis for evaluation of the bus concept is described. Installation of the system included developing both hardware and software interfaces between the bus and the specific TMS computers and terminals. The software written for the microprocessor-based bus interface units is described. The software implements both the general bus communications protocol and also the specific interface protocols for the TMS computers and terminals.

  19. Comparison and status of 32 bit backplane bus architectures

    International Nuclear Information System (INIS)

    Muller, K.D.

    1985-01-01

    With the introduction of 32 bit microprocessors several new 32 bit backplane bus architectures have been developed and are in the process for standardization. Among these are Future Bus (IEEE P896.1), VME-Bus (IEEE 1014), MULTIBUS II, Nu-Bus and Fastbus (IEEE 960). The paper describes and compares the main features of these bus architectures and mentions the status of national and international standardization efforts

  20. The seated bus passenger--a review.

    Science.gov (United States)

    Levis, J A

    1978-09-01

    The paper describes the inter-relationship of anthropometry, rig studies and dynamic testing of aspects related to problems of the seated bus passenger. It seeks to draw together sub-sections of a very large study sponsored by the government through the Transport and Road Research Laboratory and undertaken by the Human Factors Group of Leyland Truck and Bus. It is relevant to all those designing passenger carrying transport systems.

  1. The Gozo discovery bus : a successful experiment

    OpenAIRE

    Vella, Maryrose

    2008-01-01

    The introduction of a tourist discovery bus in Gozo came about as a result of an EU Project which is part of the Interreg III B Archimed programmes in which the Islands and Small States Institute of the University of Malta participated. Other countries participating in this programme besides Malta, represented by the Islands and Small States Institute, are Italy, Cyprus and Greece. The discovery bus service was aimed at encouraging more tourists to come to Gozo and enabling them to visit stra...

  2. Bus line classification using neural networks

    OpenAIRE

    Jiménez Alonso, Felipe; Serradilla García, Francisco; Román de Andrés, Alfonso; Naranjo Hernandez, Jose Eugenio

    2014-01-01

    Grouping urban bus routes is necessary when there are evidences of significant differences among them. In Jiménez et al. (2013), a reduced sample of routes was grouped into clusters utilizing kinematic measured data. As a further step, in this paper, the remaining urban bus routes of a city, for which no kinematic measurements are available, are classified. For such purpose we use macroscopic geographical and functional variables to describe each route, while the clustering process is perform...

  3. A Rule-Based Energy Management Strategy for a Plug-in Hybrid School Bus Based on a Controller Area Network Bus

    Directory of Open Access Journals (Sweden)

    Jiankun Peng

    2015-06-01

    Full Text Available This paper presents a rule-based energy management strategy for a plug-in hybrid school bus (PHSB. In order to verify the effectiveness and rationality of the proposed energy management strategy, the powertrain and control models were built with MATLAB/Simulink. The PHSB powertrain model includes an engine model, ISG (integrated started and generator model, drive motor model, power battery packs model, driver model, and vehicle longitudinal dynamics model. To evaluate the controller area network (CAN bus performance features such as the bus load, signal hysteresis, and to verify the reliability and real-time performance of the CAN bus multi-node control method, a co-simulation platform was built with CANoe and MATLAB/Simulink. The co-simulation results show that the control strategy can meet the requirements of the PHSB’s dynamic performance. Meanwhile, the charge-depleting mode (CD and charge-sustaining mode (CS can switch between each other and maintain a state-of-charge (SoC of around 30%, indicating that the energy management strategy effectively extends the working period of the CD mode and improves the fuel economy further. The energy consumption per 100 km includes 13.7 L diesel and 10.5 kW·h electricity with an initial SoC of 75%. The CANoe simulation results show that the bus communication performs well without error frames.

  4. Common mode noise on the main Tevatron bus and associated beam emittance growth

    International Nuclear Information System (INIS)

    Zhang, P.; Johnson, R.P.; Kuchnir, M.; Siergiej, D.; Wolff, D.

    1991-05-01

    Overlap of betatron tune frequencies with the power supply noise spectrum can cause transverse beam emittance growth in a storage ring. We have studied this effect for tunes near the integer, where the betatron frequency is low. By injecting noise onto the main power supply bus, it was determined that common mode noise was the dominant source of emittance growth. A noise suppression feed-back loop was then used to reduce the noise and the emittance growth. These experiments are described as are investigations of the common mode propagation along the Tevatron bus and measurements of the fields generated by common mode excitation of isolated Tevatron magnets. 3 refs., 4 figs

  5. Spacecraft Spin Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides the capability to correct unbalances of spacecraft by using dynamic measurement techniques and static/coupled measurements to provide products of...

  6. Theoretical analysis of the cumulative costs of different diesel bus alternatives for a public transport in the city of Belgrade

    Directory of Open Access Journals (Sweden)

    Jovanović Stevan S.

    2017-01-01

    Full Text Available This paper includes comparative analysis of the environmental, energetic, and financial costs of different bus propulsion, possibly applied on the public transport in the city of Belgrade. It considers the modern diesel bus, the trolleybus, the natural gas bus with the spark ignition engine, the electric bus using LiFePO4 battery, and the electric bus with ultra-capacitor. The results are presented according to the real data and the real electro-energetic situation in Serbia, with the dominantly used lignite coal as primary fuel. This model gives the exact exhaust emission of electric vehicles at the thermal power plant, enables its comparison to the internal combustion engine vehicles. The result in analysis shows that the natural gas bus is the most cost efficient in economical way with overall exploitation price of $87 per 100 km. The trolleybus is more economical then the natural gas powered bus only at high departures rate, higher than 230 per workday.

  7. Spacecraft Design Thermal Control Subsystem

    Science.gov (United States)

    Miyake, Robert N.

    2008-01-01

    The Thermal Control Subsystem engineers task is to maintain the temperature of all spacecraft components, subsystems, and the total flight system within specified limits for all flight modes from launch to end-of-mission. In some cases, specific stability and gradient temperature limits will be imposed on flight system elements. The Thermal Control Subsystem of "normal" flight systems, the mass, power, control, and sensing systems mass and power requirements are below 10% of the total flight system resources. In general the thermal control subsystem engineer is involved in all other flight subsystem designs.

  8. Spacecraft Multiple Array Communication System Performance Analysis

    Science.gov (United States)

    Hwu, Shian U.; Desilva, Kanishka; Sham, Catherine C.

    2010-01-01

    The Communication Systems Simulation Laboratory (CSSL) at the NASA Johnson Space Center is tasked to perform spacecraft and ground network communication system simulations, design validation, and performance verification. The CSSL has developed simulation tools that model spacecraft communication systems and the space and ground environment in which the tools operate. In this paper, a spacecraft communication system with multiple arrays is simulated. Multiple array combined technique is used to increase the radio frequency coverage and data rate performance. The technique is to achieve phase coherence among the phased arrays to combine the signals at the targeting receiver constructively. There are many technical challenges in spacecraft integration with a high transmit power communication system. The array combining technique can improve the communication system data rate and coverage performances without increasing the system transmit power requirements. Example simulation results indicate significant performance improvement can be achieved with phase coherence implementation.

  9. Security awareness for public bus transportation : case studies of attacks against the Israeli public bus system.

    Science.gov (United States)

    2012-03-01

    This report presents 16 case studies of attacks planned or carried out against Israeli bus targets, along with statistical data on the number, frequency, and lethality of attacks against bus targets that have taken place in Israel since 1970 and duri...

  10. 77 FR 6178 - FY 2012 Discretionary Funding Opportunities: Bus and Bus Facilities Programs (State of Good...

    Science.gov (United States)

    2012-02-07

    ... not limited to: Rail, ferry, intercity bus and private transportation providers. In order to be..., intercity bus, and private transportation providers. In order to be eligible for funding, intermodal... automobile travel, improving the pedestrian environment of a community or, use of environmental design...

  11. Digital processing data communication systems (bus systems). Digitale Prozessdaten-Kommunikations-Systeme (Bus Systeme)

    Energy Technology Data Exchange (ETDEWEB)

    Fleck, K

    1980-01-01

    After an introduction to the technology of digital processing data communication systems there are the following chapters: digital communication of processing data in automation technology, the technology of biserial communication, the implementaiton of a bus system, the data transmission of the TDC-2000 system of Honeywell's and the process bus CS 275 in the automation system TELEPERM M of Siemens AG.

  12. Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes

    Science.gov (United States)

    Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

    2015-01-01

    Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes. PMID:26294903

  13. Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes.

    Science.gov (United States)

    Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

    2015-01-01

    Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes.

  14. A bimodal power and propulsion system based on cermet fuel and heat pipe energy transport

    International Nuclear Information System (INIS)

    Polansky, G.F.; Gunther, N.A.; Rochow, R.F.; Bixler, C.H.

    1995-01-01

    Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal reactor system with performance potential to permit more than 70% of the instrumented payload of the Titan IV/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies

  15. Decentralized linear quadratic power system stabilizers for multi ...

    Indian Academy of Sciences (India)

    Introduction. Modern excitation systems considerably enhance the overall transient stability of power systems ..... to the local bus rather than the angle δ measured with respect to the remote bus. ... With this in view, the linear and nonlinear per-.

  16. Spacecraft Charge Monitor

    Science.gov (United States)

    Goembel, L.

    2003-12-01

    We are currently developing a flight prototype Spacecraft Charge Monitor (SCM) with support from NASA's Small Business Innovation Research (SBIR) program. The device will use a recently proposed high energy-resolution electron spectroscopic technique to determine spacecraft floating potential. The inspiration for the technique came from data collected by the Atmosphere Explorer (AE) satellites in the 1970s. The data available from the AE satellites indicate that the SCM may be able to determine spacecraft floating potential to within 0.1 V under certain conditions. Such accurate measurement of spacecraft charge could be used to correct biases in space plasma measurements. The device may also be able to measure spacecraft floating potential in the solar wind and in orbit around other planets.

  17. Classifying the Diversity of Bus Mapping Systems

    Science.gov (United States)

    Said, Mohd Shahmy Mohd; Forrest, David

    2018-05-01

    This study represents the first stage of an investigation into understanding the nature of different approaches to mapping bus routes and bus network, and how they may best be applied in different public transport situations. In many cities, bus services represent an important facet of easing traffic congestion and reducing pollution. However, with the entrenched car culture in many countries, persuading people to change their mode of transport is a major challenge. To promote this modal shift, people need to know what services are available and where (and when) they go. Bus service maps provide an invaluable element of providing suitable public transport information, but are often overlooked by transport planners, and are under-researched by cartographers. The method here consists of the creation of a map evaluation form and performing assessment of published bus networks maps. The analyses were completed by a combination of quantitative and qualitative data analysis of various aspects of cartographic design and classification. This paper focuses on the resulting classification, which is illustrated by a series of examples. This classification will facilitate more in depth investigations into the details of cartographic design for such maps and help direct areas for user evaluation.

  18. Power inverter with optical isolation

    Science.gov (United States)

    Duncan, Paul G.; Schroeder, John Alan

    2005-12-06

    An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

  19. VICbus: A standard inter-crate bus

    International Nuclear Information System (INIS)

    Parkman, C.F.

    1990-01-01

    VICbus is a standard inter-crate cable bus being developed by a working group of the ISO/IEC. Derived from an initiative of the VMEbus Working Group of ESONE, VICbus aims to provide users of multi-crate VMEbus and other backplane bus systems with a standard inter-crate connection. Multi-drop operation is provided for up to 31 devices on a cable of maximum 100 metres in length. Two data transfer protocols are specified, compelled (asynchronous) transfers for transparent interconnection of backplane bus systems (VMEbus in the first instance), and high-speed, non-compelled (synchronous) transfers between VICbus interfaces. A limited interrupt mechanism is specified, as well as simple, but efficient arbitration technique. Conventional technology is employed: copper cables, existing transcievers, and differential signal transmission, together with proven low-level protocols. Data transfer rates in excess of 30 Mbyte/s will be possible on a cable length of 30 metres

  20. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Second Evaluation Report and Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2009-05-01

    This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The evaluation period in this report (January 2008 through February 2009) has been chosen to coincide with a UTC Power propulsion system changeout that occurred on January 15, 2008.

  1. Risk factors affecting fatal bus accident severity: Their impact on different types of bus drivers.

    Science.gov (United States)

    Feng, Shumin; Li, Zhenning; Ci, Yusheng; Zhang, Guohui

    2016-01-01

    While the bus is generally considered to be a relatively safe means of transportation, the property losses and casualties caused by bus accidents, especially fatal ones, are far from negligible. The reasons for a driver to incur fatalities are different in each case, and it is essential to discover the underlying risk factors of bus fatality severity for different types of drivers in order to improve bus safety. The current study investigates the underlying risk factors of fatal bus accident severity to different types of drivers in the U.S. by estimating an ordered logistic model. Data for the analysis are retrieved from the Buses Involved in Fatal Accidents (BIFA) database from the USA for the years 2006-2010. Accidents are divided into three levels by counting their equivalent fatalities, and the drivers are classified into three clusters by the K-means cluster analysis. The analysis shows that some risk factors have the same impact on different types of drivers, they are: (a) season; (b) day of week; (c) time period; (d) number of vehicles involved; (e) land use; (f) manner of collision; (g) speed limit; (h) snow or ice surface condition; (i) school bus; (j) bus type and seating capacity; (k) driver's age; (l) driver's gender; (m) risky behaviors; and (n) restraint system. Results also show that some risk factors only have impact on the "young and elder drivers with history of traffic violations", they are: (a) section type; (b) number of lanes per direction; (c) roadway profile; (d) wet road surface; and (e) cyclist-bus accident. Notably, history of traffic violations has different impact on different types of bus drivers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Fractionated Spacecraft Architectures Seeding Study

    National Research Council Canada - National Science Library

    Mathieu, Charlotte; Weigel, Annalisa

    2006-01-01

    .... Models were developed from a customer-centric perspective to assess different fractionated spacecraft architectures relative to traditional spacecraft architectures using multi-attribute analysis...

  3. Spacecraft momentum control systems

    CERN Document Server

    Leve, Frederick A; Peck, Mason A

    2015-01-01

    The goal of this book is to serve both as a practical technical reference and a resource for gaining a fuller understanding of the state of the art of spacecraft momentum control systems, specifically looking at control moment gyroscopes (CMGs). As a result, the subject matter includes theory, technology, and systems engineering. The authors combine material on system-level architecture of spacecraft that feature momentum-control systems with material about the momentum-control hardware and software. This also encompasses material on the theoretical and algorithmic approaches to the control of space vehicles with CMGs. In essence, CMGs are the attitude-control actuators that make contemporary highly agile spacecraft possible. The rise of commercial Earth imaging, the advances in privately built spacecraft (including small satellites), and the growing popularity of the subject matter in academic circles over the past decade argues that now is the time for an in-depth treatment of the topic. CMGs are augmented ...

  4. Spacecraft Material Outgassing Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This compilation of outgassing data of materials intended for spacecraft use were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed...

  5. Spacecraft Fire Safety Demonstration

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Spacecraft Fire Safety Demonstration project is to develop and conduct large-scale fire safety experiments on an International Space Station...

  6. Quick spacecraft charging primer

    International Nuclear Information System (INIS)

    Larsen, Brian Arthur

    2014-01-01

    This is a presentation in PDF format which is a quick spacecraft charging primer, meant to be used for program training. It goes into detail about charging physics, RBSP examples, and how to identify charging.

  7. Development of a multi-mode hybrid electric bus

    Energy Technology Data Exchange (ETDEWEB)

    Shemmans, M.J. [Overland Custom Coach, Thorndale, ON (Canada); Bland, C. [BET Services Inc., Mississauga, ON (Canada)

    2004-04-01

    This paper describes the development of an energy efficient, low floor, 28 foot hybrid electric bus for use as an airport shuttle bus or other specialized transit operations. A multi-mode concept was also adopted to include the capability of operating in battery-only drive, engine-only drive or a range of hybrid electric drive modes. The electric drivetrain was powered by a battery pack or a combination of a battery pack and an internal combustion engine-powered electric generator. The participating companies in this project include Overland Custom Coach, BET Services Inc., Siemens and Transport Canada. The technical feasibility study was described with reference to duty cycles, performance issues, vehicle weight, mechanical drive issues, brakes, suspension, powertrain cooling, heating, ventilation, electrical system, batteries and control system. The commercial feasibility was also described in terms of capital and operating costs. Results of the prototype tests validate the possibilities of zero or reduced emission transit in real world applications. 25 tabs., 32 figs.

  8. Ecodriving for Reduction of Bus Transit Emission with Vehicle’s Hybrid Dynamic Model

    Directory of Open Access Journals (Sweden)

    Xiuzheng Zheng

    2015-01-01

    Full Text Available This paper formulates a global ecodriving optimal control to advise the green driving speed for bus transit to minimize the exhaust emission using Vehicle-to-Infrastructure (V2I communication. Assuming communication between vehicles and infrastructure (V2I and knowledge of traffic signal timings and waiting passengers at stations are known, an optimal driving speed is proposed to minimize the total vehicle emissions of the bus route. The dwell time of the bus transit at each station which includes two parts is proposed. A traffic lights timing model is employed as constraints to control the formation of the green wave band. Vehicle specific power (VSP model is further applied to evaluate the exhaust emission level linked with the speed and acceleration of the bus transit. An approximate sixteen-kilometer traffic network including fourteen intersections and fifteen stations of Beijing bus transit line 1 in Chaoyang District, Beijing, is chosen to investigate the performance of the developed ecodriving approach.

  9. Transition to a hydrogen fuel cell transit bus fleet for Canadian urban transit system

    International Nuclear Information System (INIS)

    Ducharme, P.

    2004-01-01

    'Full text:' The Canadian Transportation Fuel Cell Alliance (CTFCA), created by the Canadian Government as part of its 2000 Climate Change Action Plan, has commissioned MARCON-DDM's Hydrogen Intervention Team (HIT) to provide a roadmap for urban transit systems that wish to move to hydrogen fuel cell-powered bus fleets. HIT is currently in the process of gathering information from hydrogen technology providers, bus manufacturers, fuelling system providers and urban transit systems in Canada, the US and Europe. In September, HIT will be in a position to provide a preview of its report to the CTFCA, due for October 2004. The planned table of contents includes: TOMORROW'S FUEL CELL (FC) URBAN TRANSIT BUS - Powertrain, on-board fuel technologies - FC engine system manufacturers - Bus technical specifications, performances, operating characteristics - FC bus manufacturers TOMORROW'S FC TRANSIT PROPERTY - Added maintenance, facilities and fuelling infrastructure requirements - Supply chain implications - Environmental and safety issues - Alternative operational concepts PATHWAYS TO THE FUTURE - Choosing the future operational concept - 'Gap' assessment - how long from here to there? - Facilities and fleet adjustments, including fuelling infrastructure - Risk mitigation, code compliance measures TRANSITIONAL CONSIDERATIONS - Cost implications - Transition schedule (author)

  10. Performance of school bus retrofit systems: ultrafine particles and other vehicular pollutants.

    Science.gov (United States)

    Zhang, Qunfang; Zhu, Yifang

    2011-08-01

    This study evaluated the performance of retrofit systems for diesel-powered school buses, a diesel oxidation catalyst (DOC) muffler and a spiracle crankcase filtration system (CFS), regarding ultrafine particles (UFPs) and other air pollutants from tailpipe emissions and inside bus cabins. Tailpipe emissions and in-cabin air pollutant levels were measured before and after retrofitting when the buses were idling and during actual pick-up/drop off routes. Retrofit systems significantly reduced tailpipe emissions with a reduction of 20-94% of total particles with both DOC and CFS installed. However, no unequivocal decrease was observed for in-cabin air pollutants after retrofitting. The AC/fan unit and the surrounding air pollutant concentrations played more important roles for determining the in-cabin air quality of school buses than did retrofit technologies. Although current retrofit systems reduce children's exposure while waiting to board at a bus station, retrofitting by itself does not protect children satisfactorily from in-cabin particle exposures. Turning on the bus engine increased in-cabin UFP levels significantly only when the wind blew from the bus' tailpipe toward its hood with its windows open. This indicated that wind direction and window position are significant factors determining how much self-released tailpipe emissions may penetrate into the bus cabin. The use of an air purifier was found to remove in-cabin particles by up to 50% which might be an alternative short-to-medium term strategy to protect children's health.

  11. Deployable Brake for Spacecraft

    Science.gov (United States)

    Rausch, J. R.; Maloney, J. W.

    1987-01-01

    Aerodynamic shield that could be opened and closed proposed. Report presents concepts for deployable aerodynamic brake. Brake used by spacecraft returning from high orbit to low orbit around Earth. Spacecraft makes grazing passes through atmosphere to slow down by drag of brake. Brake flexible shield made of woven metal or ceramic withstanding high temperatures created by air friction. Stored until needed, then deployed by set of struts.

  12. The Bus Station Spacing Optimization Based on Game Theory

    Directory of Open Access Journals (Sweden)

    Changjiang Zheng

    2015-01-01

    Full Text Available With the development of city, the problem of traffic is becoming more and more serious. Developing public transportation has become the key to solving this problem in all countries. Based on the existing public transit network, how to improve the bus operation efficiency, and reduce the residents transit trip cost has become a simple and effective way to develop the public transportation. Bus stop spacing is an important factor affecting passengers’ travel time. How to set up bus stop spacing has become the key to reducing passengers’ travel time. According to comprehensive traffic survey, theoretical analysis, and summary of urban public transport characteristics, this paper analyzes the impact of bus stop spacing on passenger in-bus time cost and out-bus time cost and establishes in-bus time and out-bus time model. Finally, the paper gets the balance best station spacing by introducing the game theory.

  13. Bus accident severity and passenger injury: evidence from Denmark

    DEFF Research Database (Denmark)

    Prato, Carlo Giacomo; Kaplan, Sigal

    2014-01-01

    Purpose Bus safety is a concern not only in developing countries, but also in the U.S. and Europe. In Denmark, disentangling risk factors that are positively or negatively related to bus accident severity and injury occurrence to bus passengers can contribute to promote safety as an essential...... principle of sustainable transit and advance the vision “every accident is one too many”. Methods Bus accident data were retrieved from the national accident database for the period 2002–2011. A generalized ordered logit model allows analyzing bus accident severity and a logistic regression enables...... examining occurrence of injury to bus passengers. Results Bus accident severity is positively related to (i) the involvement of vulnerable road users, (ii) high speed limits, (iii) night hours, (iv) elderly drivers of the third party involved, and (v) bus drivers and other drivers crossing in yellow or red...

  14. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus Preliminary Evaluation Results

    Science.gov (United States)

    2008-10-16

    This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The report discusses the planned fuel cell bus demonstration and equipment us...

  15. Request-Centric Wireless Bus Information Management System

    Directory of Open Access Journals (Sweden)

    Ying-Chih Chen

    2016-11-01

    Full Text Available This invention relates to a wireless bus information management system, which includes bus stop and vehicle management subsystems. The management signals are transmittable between bus stops and the vehicle. Based on vehicle management signals, the bus stop management subsystem can obtain information about the bus route identification, the number of unoccupied seats, the intention to stop or not, etc. Similarly, with the bus stop management signals, the vehicle management subsystem can make the decision of stopping. Accordingly, when a passenger wants to get off the vehicle or there are unoccupied seats, the vehicle management subsystem will inform the bus stop management subsystem such that the passengers waiting at the bus stop may flexibly schedule their travel plan. The proposed distributed wireless system is detailed by a prototype implementation and a simulation analysis, which is shown to be feasible and scalable.

  16. An Extended IEEE 118-Bus Test System With High Renewable Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Ivonne; Martinez-Anido, Carlo Brancucci; Hodge, Bri-Mathias

    2018-01-01

    This article describes a new publicly available version of the IEEE 118-bus test system, named NREL-118. The database is based on the transmission representation (buses and lines) of the IEEE 118-bus test system, with a reconfigured generation representation using three regions of the US Western Interconnection from the latest Western Electricity Coordination Council (WECC) 2024 Common Case [1]. Time-synchronous hourly load, wind, and solar time series are provided for over one year (8784 hours). The public database presented and described in this manuscript will allow researchers to model a test power system using detailed transmission, generation, load, wind, and solar data. This database includes key additional features that add to the current IEEE 118-bus test model, such as: the inclusion of 10 generation technologies with different heat rate functions, minimum stable levels and ramping rates, GHG emissions rates, regulation and contingency reserves, and hourly time series data for one full year for load, wind and solar generation.

  17. Adaptive Sliding-Mode Control in Bus Voltage for an Islanded DC Microgrid

    Directory of Open Access Journals (Sweden)

    Dan Zhang

    2017-01-01

    Full Text Available The control of bus voltage is a crucial task for the stable operation of islanded DC microgrids. To improve the DC bus voltage control dynamics and stability, this paper proposes an adaptive sliding-mode control method based on large-signal model. The sliding-mode control, adaptive observation, and fix-frequency pulse width modulation technology are adopted and combined efficiently, which guarantee stable bus voltage and the constant switching frequency of closed-loop system, regardless of how the parameters vary with the variable constant-power loads and uncertainties. In addition, the reference values can be quickly tracked by the state variables using the proposed method without any additional sensors/hardware circuits. Therefore, this method is beneficial for the scalability and plug-play of the distributed generators and loads within the DC microgrids. The performance of the proposed control method has been successfully verified in simulation.

  18. Energy management strategy based on fuzzy logic for a fuel cell hybrid bus

    Science.gov (United States)

    Gao, Dawei; Jin, Zhenhua; Lu, Qingchun

    Fuel cell vehicles, as a substitute for internal-combustion-engine vehicles, have become a research hotspot for most automobile manufacturers all over the world. Fuel cell systems have disadvantages, such as high cost, slow response and no regenerative energy recovery during braking; hybridization can be a solution to these drawbacks. This paper presents a fuel cell hybrid bus which is equipped with a fuel cell system and two energy storage devices, i.e., a battery and an ultracapacitor. An energy management strategy based on fuzzy logic, which is employed to control the power flow of the vehicular power train, is described. This strategy is capable of determining the desired output power of the fuel cell system, battery and ultracapacitor according to the propulsion power and recuperated braking power. Some tests to verify the strategy were developed, and the results of the tests show the effectiveness of the proposed energy management strategy and the good performance of the fuel cell hybrid bus.

  19. Security awareness for public bus transportation : case studies of attacks against the Israeli public bus system [research brief].

    Science.gov (United States)

    2012-03-01

    Government regulators and transportation operators of public bus systems are concerned about terrorist attacks. Bus attacks in Israel between late September 2000 and the end of 2006, a period known as the Second Intifada, are particularly well known....

  20. Flexible solar strips light up campus bus shelter at McMaster

    Energy Technology Data Exchange (ETDEWEB)

    Anon,

    2009-10-15

    This article described the installation of solar cells to illuminate a bus shelter on the campus of McMaster University. The innovative flexible solar cell technology was developed by a group of engineering researchers at the university who are hoping that the prototype will help commercialize the new technology. The solar technology is suitable for lighting up bus shelter signage and providing light for general safety. One of the main features of the technology is the ability to bend the solar cells to fit the curved roof of the bus shelter. The flexibility is achieved by tilting a large number of small silicon elements into an array, mounting them onto a flexible sheet, and connecting them through a proprietary method. The 2 solar strips installed on the roof of the bus shelter are about 90 centimeters long and 12 centimeters wide. Each strip has 720 one-centimetre square solar cells and generates up to 4.5 Watts of power. The solar strip is connected to 2 energy-efficient, multi-LED, light fixtures. Each light fixture uses only 600 milliwatts of power and produces about the same light output as a three watt regular tungsten bulb. The installation is being monitored to determine how much solar power is needed to fully recharge the batteries based on weather conditions, particularly during the winter months. 5 figs.

  1. High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

    Science.gov (United States)

    Murty, Balarama Vempaty

    2000-01-01

    A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

  2. Autonomous Spacecraft Communication Interface for Load Planning

    Science.gov (United States)

    Dever, Timothy P.; May, Ryan D.; Morris, Paul H.

    2014-01-01

    Ground-based controllers can remain in continuous communication with spacecraft in low Earth orbit (LEO) with near-instantaneous communication speeds. This permits near real-time control of all of the core spacecraft systems by ground personnel. However, as NASA missions move beyond LEO, light-time communication delay issues, such as time lag and low bandwidth, will prohibit this type of operation. As missions become more distant, autonomous control of manned spacecraft will be required. The focus of this paper is the power subsystem. For present missions, controllers on the ground develop a complete schedule of power usage for all spacecraft components. This paper presents work currently underway at NASA to develop an architecture for an autonomous spacecraft, and focuses on the development of communication between the Mission Manager and the Autonomous Power Controller. These two systems must work together in order to plan future load use and respond to unanticipated plan deviations. Using a nominal spacecraft architecture and prototype versions of these two key components, a number of simulations are run under a variety of operational conditions, enabling development of content and format of the messages necessary to achieve the desired goals. The goals include negotiation of a load schedule that meets the global requirements (contained in the Mission Manager) and local power system requirements (contained in the Autonomous Power Controller), and communication of off-plan disturbances that arise while executing a negotiated plan. The message content is developed in two steps: first, a set of rapid-prototyping "paper" simulations are preformed; then the resultant optimized messages are codified for computer communication for use in automated testing.

  3. 76 FR 68819 - State of Good Repair Bus and Bus Facilities Discretionary Program Funds

    Science.gov (United States)

    2011-11-07

    ... Availability on June 24, 2011. The SGR Initiative makes funds available to public transit providers to finance capital projects to replace, rehabilitate, and purchase buses and related equipment and to construct bus...

  4. 76 FR 37393 - FY 2011 Discretionary Livability Funding Opportunity; Section 5309 Bus and Bus Facilities...

    Science.gov (United States)

    2011-06-27

    ... 90 percent Federal share for the total cost of a biodiesel bus. The Act also allows a 90 percent... transit systems or roadways. iv. Will improve accessibility and transport services for economically...

  5. Telemetry Timing Analysis for Image Reconstruction of Kompsat Spacecraft

    Directory of Open Access Journals (Sweden)

    Jin-Ho Lee

    2000-06-01

    Full Text Available The KOMPSAT (KOrea Multi-Purpose SATellite has two optical imaging instruments called EOC (Electro-Optical Camera and OSMI (Ocean Scanning Multispectral Imager. The image data of these instruments are transmitted to ground station and restored correctly after post-processing with the telemetry data transferred from KOMPSAT spacecraft. The major timing information of the KOMPSAT is OBT (On-Board Time which is formatted by the on-board computer of the spacecraft, based on 1Hz sync. pulse coming from the GPS receiver involved. The OBT is transmitted to ground station with the house-keeping telemetry data of the spacecraft while it is distributed to the instruments via 1553B data bus for synchronization during imaging and formatting. The timing information contained in the spacecraft telemetry data would have direct relation to the image data of the instruments, which should be well explained to get a more accurate image. This paper addresses the timing analysis of the KOMPSAT spacecraft and instruments, including the gyro data timing analysis for the correct restoration of the EOC and OSMI image data at ground station.

  6. Advanced Competencies for School Bus Drivers.

    Science.gov (United States)

    Illinois State Board of Education, Springfield.

    Four units are provided for formal classroom instruction in advanced competencies for school bus drivers in Illinois. Units cover passenger control, accidents and emergencies, detecting hazards, and first aid. Each unit contains some or all of the following components: table of contents; a list of objectives; informative material, including an…

  7. Functional Bus Driver-Pupil Passenger Relationships.

    Science.gov (United States)

    Farmer, Ernest

    1987-01-01

    Successful school bus drivers bring much more than mechanical know-how to the job. They develop good rapport with students while acting to bring undesirable student behavior under control. Drivers must also show an interest in students' welfare and have a good sense of humor. (MLH)

  8. School Bus Accidents: Reducing Incidents and Injuries

    Science.gov (United States)

    Mahoney, Daniel

    2009-01-01

    The number of children injured in nonfatal school bus accidents annually is more than double the number previously estimated. In Ohio alone, approximately 20,800 children younger than 18 were occupants of school buses that were involved in crashes in 2003 and 2004 (McGeehan 2007). Among those children, most had minor or no injuries. However, there…

  9. An Experimental Platform for Autonomous Bus Development

    Directory of Open Access Journals (Sweden)

    Héctor Montes

    2017-11-01

    Full Text Available Nowadays, with highly developed instrumentation, sensing and actuation technologies, it is possible to foresee an important advance in the field of autonomous and/or semi-autonomous transportation systems. Intelligent Transport Systems (ITS have been subjected to very active research for many years, and Bus Rapid Transit (BRT is one area of major interest. Among the most promising transport infrastructures, the articulated bus is an interesting, low cost, high occupancy capacity and friendly option. In this paper, an experimental platform for research on the automatic control of an articulated bus is presented. The aim of the platform is to allow full experimentation in real conditions for testing technological developments and control algorithms. The experimental platform consists of a mobile component (a commercial articulated bus fully instrumented and a ground test area composed of asphalt roads inside the Consejo Superior de Investigaciones Científicas (CSIC premises. This paper focuses also on the development of a human machine interface to ease progress in control system evaluation. Some experimental results are presented in order to show the potential of the proposed platform.

  10. Bus safety study : a report to Congress.

    Science.gov (United States)

    2013-11-01

    Section 20021(b) of the Moving Ahead for Progress for the 21st Century (MAP-21) legislation requires the Secretary of Transportation : to submit a report of the results of a Bus Safety Study to the Committee on Banking, Housing, and Urban Affai...

  11. Technology Validation: Fuel Cell Bus Evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, Leslie [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-02

    This presentation describing the FY 2016 accomplishments for the National Renewable Energy Laboratory's Fuel Cell Bus Evaluations project was presented at the U.S. Department of Energy Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting, June 7, 2016.

  12. Repeater For A Digital-Communication Bus

    Science.gov (United States)

    Torres-Guzman, Esteban; Olson, Stephen; Heaps, Tim

    1993-01-01

    Digital repeater circuit designed to extend range of communication on MIL-STD-1553 bus beyond original maximum allowable length of 300 ft. Circuit provides two-way communication, one way at time, and conforms to specifications of MIL-STD-1553. Crosstalk and instability eliminated.

  13. Energy DataBus (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-07-01

    NREL has developed the Energy DataBus, an open-sourced software that collects massive amounts of energy-related data at second-to-second intervals; stores it in a massive, scalable database; and turns it into useful information.

  14. Stochastic Bus Dispatching Model untuk Optimalisasi Jumlah Bus Transjakarta Koridor 3

    Directory of Open Access Journals (Sweden)

    Zahedi Zahedi

    2011-12-01

    Full Text Available The increasing number of road user causing traffic jam finds out a way, busway. However, in its implementation, the number of fleet available does not enough to take the passengers. It results in the an amassed of passengers at several bus stops. This leads to passenger dissatisfaction satisfaction which eventually causes Transjakarta users to reuse private cars. Definitely this situation may builds up traffic jams. Stochastic Bus Dispatching Model is used to simulate public transportation that operates regularly. 

  15. Internet Technology on Spacecraft

    Science.gov (United States)

    Rash, James; Parise, Ron; Hogie, Keith; Criscuolo, Ed; Langston, Jim; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The Operating Missions as Nodes on the Internet (OMNI) project has shown that Internet technology works in space missions through a demonstration using the UoSAT-12 spacecraft. An Internet Protocol (IP) stack was installed on the orbiting UoSAT-12 spacecraft and tests were run to demonstrate Internet connectivity and measure performance. This also forms the basis for demonstrating subsequent scenarios. This approach provides capabilities heretofore either too expensive or simply not feasible such as reconfiguration on orbit. The OMNI project recognized the need to reduce the risk perceived by mission managers and did this with a multi-phase strategy. In the initial phase, the concepts were implemented in a prototype system that includes space similar components communicating over the TDRS (space network) and the terrestrial Internet. The demonstration system includes a simulated spacecraft with sample instruments. Over 25 demonstrations have been given to mission and project managers, National Aeronautics and Space Administration (NASA), Department of Defense (DoD), contractor technologists and other decisions makers, This initial phase reached a high point with an OMNI demonstration given from a booth at the Johnson Space Center (JSC) Inspection Day 99 exhibition. The proof to mission managers is provided during this second phase with year 2000 accomplishments: testing the use of Internet technologies onboard an actual spacecraft. This was done with a series of tests performed using the UoSAT-12 spacecraft. This spacecraft was reconfigured on orbit at very low cost. The total period between concept and the first tests was only 6 months! On board software was modified to add an IP stack to support basic IP communications. Also added was support for ping, traceroute and network timing protocol (NTP) tests. These tests show that basic Internet functionality can be used onboard spacecraft. The performance of data was measured to show no degradation from current

  16. POWER CONTROL OF A BIDIRECTIONAL DC BUS FOR FUEL CELLS APPLICATIONS CONTROL DE POTENCIA DE UN BUS DC BIDIRECCIONAL PARA APLICACIONES DE PILAS DE COMBUSTIBLE CONTROLE DE POTÊNCIA DE UM ÔNIBUS DC BIDIRECIONAL PARA APLICAÇÕES DE PILHAS DE COMBUSTÍVE

    Directory of Open Access Journals (Sweden)

    Andrés Fernando Restrepo

    2012-12-01

    Full Text Available This paper proposes a power system for fuel cell applications able to transfer energy from the power source to the load, and to charge an auxiliary storage device using regenerative power flows generated by the load. The solution is based on a closed loop bidirectional DC/DC converter, where additional devices have been also designed to experimentally test the solution in a safe and realistic environment: a fuel cell emulator and an electronic load.Este artículo propone un sistema de potencia para aplicaciones de pilas de combustible capaz de transferir energía de la fuente de potencia a la carga y de cargar un sistema de almacenamiento con flujos regenerativos de potencia desde la carga. La solución está basada en un convertidor bidireccional DC/DC en lazo cerrado. Además, se presentan dispositivos auxiliares diseñados para evaluar experimentalmente la solución en un entorno seguro y realista: un emulador de pila de combustible y una carga electrónica.Este artigo propõe um sistema de potência para aplicações de pilhas de combustível capaz de transferir energia da fonte de potência à carga e de carregar um sistema de armazenamento com fluxos regenerativos de potência desde a carga. A solução está baseada em um conversor bidirecional DC/DC em laço fechado. Ademais, apresentam-se dispositivos auxiliares desenhados para avaliar experimentalmente a solução em um meio seguro e realista: um emulador de pilha de combustível e uma carga eletrônica.

  17. Mechanical Design of Spacecraft

    Science.gov (United States)

    1962-01-01

    In the spring of 1962, engineers from the Engineering Mechanics Division of the Jet Propulsion Laboratory gave a series of lectures on spacecraft design at the Engineering Design seminars conducted at the California Institute of Technology. Several of these lectures were subsequently given at Stanford University as part of the Space Technology seminar series sponsored by the Department of Aeronautics and Astronautics. Presented here are notes taken from these lectures. The lectures were conceived with the intent of providing the audience with a glimpse of the activities of a few mechanical engineers who are involved in designing, building, and testing spacecraft. Engineering courses generally consist of heavily idealized problems in order to allow the more efficient teaching of mathematical technique. Students, therefore, receive a somewhat limited exposure to actual engineering problems, which are typified by more unknowns than equations. For this reason it was considered valuable to demonstrate some of the problems faced by spacecraft designers, the processes used to arrive at solutions, and the interactions between the engineer and the remainder of the organization in which he is constrained to operate. These lecture notes are not so much a compilation of sophisticated techniques of analysis as they are a collection of examples of spacecraft hardware and associated problems. They will be of interest not so much to the experienced spacecraft designer as to those who wonder what part the mechanical engineer plays in an effort such as the exploration of space.

  18. Embedded Thermal Control for Spacecraft Subsystems Miniaturization

    Science.gov (United States)

    Didion, Jeffrey R.

    2014-01-01

    Optimization of spacecraft size, weight and power (SWaP) resources is an explicit technical priority at Goddard Space Flight Center. Embedded Thermal Control Subsystems are a promising technology with many cross cutting NSAA, DoD and commercial applications: 1.) CubeSatSmallSat spacecraft architecture, 2.) high performance computing, 3.) On-board spacecraft electronics, 4.) Power electronics and RF arrays. The Embedded Thermal Control Subsystem technology development efforts focus on component, board and enclosure level devices that will ultimately include intelligent capabilities. The presentation will discuss electric, capillary and hybrid based hardware research and development efforts at Goddard Space Flight Center. The Embedded Thermal Control Subsystem development program consists of interrelated sub-initiatives, e.g., chip component level thermal control devices, self-sensing thermal management, advanced manufactured structures. This presentation includes technical status and progress on each of these investigations. Future sub-initiatives, technical milestones and program goals will be presented.

  19. Radiation Effects on Spacecraft Structural Materials

    International Nuclear Information System (INIS)

    Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

    2002-01-01

    Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

  20. Attitude Estimation in Fractionated Spacecraft Cluster Systems

    Science.gov (United States)

    Hadaegh, Fred Y.; Blackmore, James C.

    2011-01-01

    An attitude estimation was examined in fractioned free-flying spacecraft. Instead of a single, monolithic spacecraft, a fractionated free-flying spacecraft uses multiple spacecraft modules. These modules are connected only through wireless communication links and, potentially, wireless power links. The key advantage of this concept is the ability to respond to uncertainty. For example, if a single spacecraft module in the cluster fails, a new one can be launched at a lower cost and risk than would be incurred with onorbit servicing or replacement of the monolithic spacecraft. In order to create such a system, however, it is essential to know what the navigation capabilities of the fractionated system are as a function of the capabilities of the individual modules, and to have an algorithm that can perform estimation of the attitudes and relative positions of the modules with fractionated sensing capabilities. Looking specifically at fractionated attitude estimation with startrackers and optical relative attitude sensors, a set of mathematical tools has been developed that specify the set of sensors necessary to ensure that the attitude of the entire cluster ( cluster attitude ) can be observed. Also developed was a navigation filter that can estimate the cluster attitude if these conditions are satisfied. Each module in the cluster may have either a startracker, a relative attitude sensor, or both. An extended Kalman filter can be used to estimate the attitude of all modules. A range of estimation performances can be achieved depending on the sensors used and the topology of the sensing network.

  1. Hybrid spacecraft attitude control system

    Directory of Open Access Journals (Sweden)

    Renuganth Varatharajoo

    2016-02-01

    Full Text Available The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.

  2. Design of a steering stabilizer based on CAN bus

    Science.gov (United States)

    Zhan, Zhaomin; Yan, Yibin

    2018-04-01

    This design realizes a posture correction device of griping steering wheel based on CAN bus, which is embedded in the steering wheel of vehicles. The system aims to detect the drivers' abnormal griping postures and provides drivers with classification alerts, by combining the recorded griping postures data and the vehicle speed data that are obtained via the CAN bus. The warning information are automatically stored and retained in the device for 12 months. To enhance the alerting effect, the count of this warning message for both the latest month and the last 12 months are displayed on the dashboard panel. In addition to prevent itself from being blocked and self-detect any faults in advance, the appliance also provide a self-test function, which will communicate with the integrated instrument system in vehicle and do simulation test right after the vehicle power on. This appliance can help to urge and ensure drivers to operate the steering wheel correctly, effectively, and timely; prevent some typical incorrect behaviors which commonly happen along with the change of griping postures, such as the using cellphone, and ultimately, reduce the incidence of traffic accidents.

  3. Diesel bus emissions measured in a tunnel study.

    Science.gov (United States)

    Jamriska, Milan; Morawska, Lidia; Thomas, Steven; He, Congrong

    2004-12-15

    The emission factors of a bus fleet consisting of approximately 300 diesel-powered buses were measured in a tunnel study under well-controlled conditions during a 2-d monitoring campaign in Brisbane. Particle number and mass concentration levels of submicrometer particles and PM2.5 were monitored by SMPS and DustTrak instruments at the tunnel's entrance and exit, respectively. Correlation between DustTrak and TEOM response to diesel emissions was assessed, and the DustTrak results were recalculated into TEOM equivalent data. The mean value of the number and mass emission factors was (3.11+/-2.41) x 10(14) particles km(-1) for submicrometer particles and 583+/-451 mg km(-1) for PM2.5 (DustTrak), respectively. TEOM PM2.5 equivalent emission factor was 267+/-207 mg km(-1). The results are in good agreement with the emission factors determined from steady-state dynamometer testing of 12 buses from the same Brisbane City bus fleet. The results indicate that when carefully designed, both approaches, the dynamometer and on-road studies, can provide comparable results, applicable for the assessment of the effect of traffic emissions on airborne particle pollution. A brief overview of emission factors determined from other on-road and dynamometer studies reported in the literature as well as with the regulatory values used for the vehicle emission inventory assessment is presented and compared with the results obtained in this study.

  4. Spacecraft Attitude Determination

    DEFF Research Database (Denmark)

    Bak, Thomas

    This thesis describes the development of an attitude determination system for spacecraft based only on magnetic field measurements. The need for such system is motivated by the increased demands for inexpensive, lightweight solutions for small spacecraft. These spacecraft demands full attitude...... determination based on simple, reliable sensors. Meeting these objectives with a single vector magnetometer is difficult and requires temporal fusion of data in order to avoid local observability problems. In order to guaranteed globally nonsingular solutions, quaternions are generally the preferred attitude...... is a detailed study of the influence of approximations in the modeling of the system. The quantitative effects of errors in the process and noise statistics are discussed in detail. The third contribution is the introduction of these methods to the attitude determination on-board the Ørsted satellite...

  5. Shuttle bus services quality assessment Tangerang Selatan toward smart city

    Science.gov (United States)

    Fassa, Ferdinand; Sitorus, Fredy Jhon Philip; Adikesuma, Tri Nugraha

    2017-11-01

    Around the world, shuttle bus operation played the significant role to accommodate transportation for commuting bus passengers. Shuttle Bus services in cities are provided by various bus agencies with kinds of own specific purposes. For instance, at Tangerang Selatan, Indonesia, it was said that shuttle bus In Trans Bintaro is run and operated by private bus companies hire by Bintaro developer. The aim of this research is to identify factors of satisfaction of shuttle bus service in Kota Tangerang Selatan, Indonesia. Several factors are used to analyze sums of 20 parameters performance indicators of Shuttle Bus. A face to face interview using a questionnaire (N=200) was used to collect data on October and March 2017. Likert and diagram Cartesian were used to model the all the parameters. This research succeeded in finding some categories of Shuttle bus service attributes such as accessibility, comfort, and safety. Users agreed that eight indicators in shuttle bus have the excellent achievement, while three indicators on performance remain low and should receive more attention especially punctuality of the bus.

  6. Revamping Spacecraft Operational Intelligence

    Science.gov (United States)

    Hwang, Victor

    2012-01-01

    The EPOXI flight mission has been testing a new commercial system, Splunk, which employs data mining techniques to organize and present spacecraft telemetry data in a high-level manner. By abstracting away data-source specific details, Splunk unifies arbitrary data formats into one uniform system. This not only reduces the time and effort for retrieving relevant data, but it also increases operational visibility by allowing a spacecraft team to correlate data across many different sources. Splunk's scalable architecture coupled with its graphing modules also provide a solid toolset for generating data visualizations and building real-time applications such as browser-based telemetry displays.

  7. An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

    Directory of Open Access Journals (Sweden)

    Muhamad Zalani Daud

    2014-01-01

    Full Text Available This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV system with battery energy storage (BES. The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC. For the grid side VSC (G-VSC, two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

  8. An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

    Science.gov (United States)

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

  9. VME bus based microcomputer system boards

    International Nuclear Information System (INIS)

    Chandra, A.K.; Ganesh, G.; Mayya, Anuradha; Chachondia, A.S.; Premraj, M.K.

    1991-01-01

    Several operator information systems for nuclear plants has been developed in the Division and these have involved extensive use of microcomputer boards for achieving various functions. Standard VME bus based boards have been developed to provide the most used functions. These boards have been fabricated and tested and used in several systems including Channel Temperature Monitoring systems, Disturbance Recording Systems etc. and are also proposed to be used in additional systems under developement. The use of standard bus and boards provides considerable savings in engineering time, prototyping, testing and evaluation costs, and maintenance support. This report desribes the various boards developed and the functions available on each. (author). 4 refs., 11 figs., 3 appendixes

  10. Terminals for Suburb Bus Transport in Bratislava

    Science.gov (United States)

    Schlosser, Tibor; Schlosser, Peter; Cápayová, Silvia; Hodáková, Dominika

    2017-10-01

    The main objective of this article is to describe the strategy for development of the public transport terminals in the city of Bratislava, Capital of Slovak Republic. The reason goes from the private operator Slovak Lines, who operates the suburb bus transport in the agglomeration of the city. For this operator was created a transport model, while placing emphasis on optimizing the compliance of suburban public transport with urban public transport in the city of Bratislava and evaluating the significance of the new Bus Station to be constructed at Mlynské Nivy - in a new down town centre of the city. The main issue is to ensure the best available offer of public transport (PT) to passengers in the Bratislava agglomeration. The subject of the study was oriented to specify and propose changes in the transport infrastructure and integrated public transport organisation on the area of the city in terms of the significant position of the new Mlynské Nivy Bus Station (MN BS), which is under preparation with realization in the year 2017.

  11. Multi Bus DC-DC Converter in Electric Hybrid Vehicles

    Science.gov (United States)

    Krithika, V.; Subramaniam, C.; Sridharan, R.; Geetha, A.

    2018-04-01

    This paper is cotncerned with the design, simulation and fabrication of the prototype of a Multi bus DC- DC converter operating from 42V DC and delivering 14V DC and 260V DC. As a result, three DC buses are interconnected through a single power electronic circuitry. Such a requirement is energized in the development of a hybrid electric automobile which uses the technology of fuel cell. This is implemented by using a Bidirectional DC-DC converter configuration which is ideally suitable for multiple outputs with mutual electrical isolation. For the sake of reduced size and cost of step-up transformer, selection of a high frequency switching cycle at 10 KHz was done.

  12. FAKTOR PENYEBAB KERUSAKAN SISTEM MESIN PADA BUS APTB PPD

    Directory of Open Access Journals (Sweden)

    Laela Chairani

    2015-06-01

    Full Text Available Comfort and safety of public transportation, particularly APTB PPD buses, becomes high expectations for its customers. Those expectations must be supported by the application of a good engine maintenance system. By using the method of Reliability Centered Maintenance may be determined appropriate actions to mitigate damage. From the analysis known the failures of the APTB PPD bus are malfunctions of the fuel engine, power transfer systems, difficulty to move the gear lever, and lubricating system for the rough engine noise. The cause of engine malfunction is dirty diesel filter, vehicle acceleration malfunction is due to the clutch plate wear out. Difficulty to move the gear lever indicates that the clutch slips. Rough engine noise caused by the flow of oil to the engine stalled as the result of dirty oil filter. The results of the logic tree analysis show that for each failure requires scheduling of time directed task.

  13. Forecasting of harmonics distortions in electric power systems, using impedance matrix of harmonic bus; Previsao de distorcoes harmonicas em sistemas eletricos de potencia, utilizando-se matriz impedancia de barra harmonica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clider Adriane de Sousa

    1993-11-01

    The present work is a contribution to the study of harmonics in electric power systems. It presents a focus returned to the planning area, in the sense of evaluating in a qualitative way the possible situations of harmonic distortions of voltage that can occur when of the installation of electric loads with not-linear behaviors in a power system. Using the domain of the frequency, as well as a monophase treatment, it intends to present a computational method of simple and fast processing to be used for evaluation of these harmonic distortions of voltage in power systems. Its main characteristic is the methodology used for the treatment of the harmonic injections on the part of non-linear loads, that it allows to supply a previous diagnosis of the behavior of the system, before the presence of such loads, before even of its effective installation.

  14. Advanced Solar-propelled Cargo Spacecraft for Mars Missions

    Science.gov (United States)

    Auziasdeturenne, Jacqueline; Beall, Mark; Burianek, Joseph; Cinniger, Anna; Dunmire, Barbrina; Haberman, Eric; Iwamoto, James; Johnson, Stephen; Mccracken, Shawn; Miller, Melanie

    1989-01-01

    Three concepts for an unmanned, solar powered, cargo spacecraft for Mars support missions were investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: A Solar Radiation Absorption (SRA) system, a Solar-Pumped Laser (SPL) system and a solar powered magnetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sunsynchronous Earth orbit converts solar energy to laser energy. The MPD system used indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary propulsion system boosts the payload into a Hohmann transfer to Mars. The SPL spacecraft and the SPL powered spacecraft return to Earth for subsequent missions. The MPD propelled spacecraft, however, remains at Mars as an orbiting space station. A patched conic approximation was used to determine a heliocentric interplanetary transfer orbit for the MPD propelled spacecraft. All three solar-powered spacecraft use an aerobrake procedure to place the payload into a low Mars parking orbit. The payload delivery times range from 160 days to 873 days (2.39 years).

  15. The Preliminary Design of a Standardized Spacecraft Bus for Small Tactical Satellites (Volume 2)

    Science.gov (United States)

    1996-11-01

    Module Inowerio Moddlile PoTanpotaio 0,03d Sysem0es90.47 MMino MCost~, Miemf MindCostofLaune 0.1541 0.1072 Max Me Tonna Availabilit ProgrmsRis 00.1776...shot propulsion; usually used for orbit insertion in launch systems LIQUID Water Electrolysis Complicated; not developed for commercial use; high...spills and leaks. Since hydrazine reacts with air, as well as some metal oxides and oxidizing agents, and absorbs water readily, storage and transport

  16. Advanced Stirling Convertor Control Unit Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

    Science.gov (United States)

    Dugala, Gina M.; Taylor, Linda M.; Kussmaul, Michael; Casciani, Michael; Brown, Gregory; Wiser, Joel

    2017-01-01

    interactions between as many as 3 radioisotope power generators, associated control strategies, and typical electric system loads. The first phase of testing included a DASCS which was developed by Johns Hopkins UniversityApplied Physics Laboratory and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. Testing included the following spacecraft electrical energy storage configurations: capacitive, battery, and supercapacitor. Testing of the DASCS and ACU in each energy storage configuration included simulation of a typical mission profile, and transient voltage and current data during load turn-on/turn-off. Testing for these devices also included the initiation of several system faults such as short circuits, electrical bus over-voltage, under-voltage and a dead bus recovery to restore normal power operations. The goal of this testing was to verify operation of the ACU(s) when connected to a spacecraft electrical bus.

  17. Conceptual design and development of a superconducting bus-line for the Large Helical Device

    International Nuclear Information System (INIS)

    Mito, T.; Takahata, K.; Yamada, S.; Yamamoto, J.; Uede, T.; Ikeda, M.

    1993-01-01

    A superconducting bus-line is proposed and preliminarily tested as an electrical feeder between the superconducting coils of the Large Helical Device (LHD) and their electrical power supply. The bus-line consists of a superconductor and its cryogenic transfer-line. The superconductor is a specially developed aluminum stabilized NbTi wire, which is installed in the innermost channel of the transfer-line. The vacuum insulated transfer-line consists of four corrugated tubes assembled coaxially. Liquid helium flows through the innermost channel and shield gas flows through another annular channel in the line. We are completing the conceptual design of the bus-line and the installation plan for the LHD experimental hall and are carrying out development of wires, including an investigation of their mechanical properties and electrical insulation. This report describes the conceptual design of the superconducting bus-line for the LHD, and the results we obtained recently during the design and development of a full-scale demonstration facility. (orig.)

  18. Optimal energy management for a series-parallel hybrid electric bus

    International Nuclear Information System (INIS)

    Xiong Weiwei; Zhang Yong; Yin Chengliang

    2009-01-01

    This paper aims to present a new type of series-parallel hybrid electric bus and its energy management strategy. This hybrid bus is a post-transmission coupled system employing a novel transmission as the series-parallel configuration switcher. In this paper, the vehicle architecture, transmission scheme and numerical models are presented. The energy management system governs the mode switching between the series mode and the parallel mode as well as the instantaneous power distribution. In this work, two separated controllers using fuzzy logic called Mode Decision and Parallel-driving Energy Management are employed to fulfill these two tasks. The energy management strategy and the applications of fuzzy logic are described. The strategy is validated by a forward-facing simulation program based on the software Matlab/Simulink. The results show that the energy management strategy is effective to control the engine operating in a high-efficiency region as well as to sustain the battery charge state while satisfy the drive ability. The energy consumption is theoretically reduced by 30.3% to that of the conventional bus under transit bus driving cycle. In addition, works need future study are also presented.

  19. Cathode power distribution system and method of using the same for power distribution

    Science.gov (United States)

    Williamson, Mark A; Wiedmeyer, Stanley G; Koehl, Eugene R; Bailey, James L; Willit, James L; Barnes, Laurel A; Blaskovitz, Robert J

    2014-11-11

    Embodiments include a cathode power distribution system and/or method of using the same for power distribution. The cathode power distribution system includes a plurality of cathode assemblies. Each cathode assembly of the plurality of cathode assemblies includes a plurality of cathode rods. The system also includes a plurality of bus bars configured to distribute current to each of the plurality of cathode assemblies. The plurality of bus bars include a first bus bar configured to distribute the current to first ends of the plurality of cathode assemblies and a second bus bar configured to distribute the current to second ends of the plurality of cathode assemblies.

  20. Peptic ulcer among urban bus drivers in Denmark

    DEFF Research Database (Denmark)

    Netterstrøm, Bo; Juel, K

    1990-01-01

    As part of a survey on the work environment of bus drivers, 2045 (83%) of 2465 male bus drivers in the three major cities in Denmark in 1978 answered a postal questionnaire on health and working conditions. In order to evaluate the relative occurrence of peptic ulcer among the bus drivers, a follow......-up study was also conducted. All hospital discharges with a peptic ulcer diagnosis among the bus drivers were registered from the Danish National Patient Register. All Danish men were used as reference group. On the basis of the 1978-questionnaire association between occupational and psychosocial factors...... and subsequent hospital discharge with a peptic ulcer diagnosis was studied. The prevalence of abdominal pain alleviated by food intake was 12% among bus drivers and 6% in the reference group. The incidence of hospital discharge with duodenal ulcer among younger bus drivers was twice the incidence among Danish...

  1. Aspek Hukum Perlindungan terhadap Penumpang Bus dalam Mewujudkan Perlindungan Konsumen

    OpenAIRE

    Harahap, Rabiah Z

    2016-01-01

    Bus is the one of transportation which is often used by society. Society as passenger of bus righteously gains protection. Many of accident happens in public transportation especially bus that rises a question the important of protection for people as the accicent victim. This question is worthy to be solved because many of public transportation company ignores the passenger's right. Based on this, government shall take control with presentation of new regulation that aims protection people ...

  2. Emission inventory estimation of an intercity bus terminal.

    Science.gov (United States)

    Qiu, Zhaowen; Li, Xiaoxia; Hao, Yanzhao; Deng, Shunxi; Gao, H Oliver

    2016-06-01

    Intercity bus terminals are hotspots of air pollution due to concentrated activities of diesel buses. In order to evaluate the bus terminals' impact on air quality, it is necessary to estimate the associated mobile emission inventories. Since the vehicles' operating condition at the bus terminal varies significantly, conventional calculation of the emissions based on average emission factors suffers the loss of accuracy. In this study, we examined a typical intercity bus terminal-the Southern City Bus Station of Xi'an, China-using a multi-scale emission model-(US EPA's MOVES model)-to quantity the vehicle emission inventory. A representative operating cycle for buses within the station is constructed. The emission inventory was then estimated using detailed inputs including vehicle ages, operating speeds, operating schedules, and operating mode distribution, as well as meteorological data (temperature and humidity). Five functional areas (bus yard, platforms, disembarking area, bus travel routes within the station, and bus entrance/exit routes) at the terminal were identified, and the bus operation cycle was established using the micro-trip cycle construction method. Results of our case study showed that switching to compressed natural gas (CNG) from diesel fuel could reduce PM2.5 and CO emissions by 85.64 and 6.21 %, respectively, in the microenvironment of the bus terminal. When CNG is used, tail pipe exhaust PM2.5 emission is significantly reduced, even less than brake wear PM2.5. The estimated bus operating cycles can also offer researchers and policy makers important information for emission evaluation in the planning and design of any typical intercity bus terminals of a similar scale.

  3. Design Report for Isolated RS-485 Bus Node

    Science.gov (United States)

    2016-07-01

    TERMS Android , RS-485, isolated, USB, smartphone 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER...controlled wired RS-485 network. The Android -based smartphone or tablet is used in conjunction with a USB to serial bridge to operate as the bus master in...the system. The Android device operates in USB Host mode and communicates to the RS-485 bus as if a single peripheral on the USB bus. 15. SUBJECT

  4. Network Analysis of Urban Traffic with Big Bus Data

    OpenAIRE

    Zhao, Kai

    2016-01-01

    Urban traffic analysis is crucial for traffic forecasting systems, urban planning and, more recently, various mobile and network applications. In this paper, we analyse urban traffic with network and statistical methods. Our analysis is based on one big bus dataset containing 45 million bus arrival samples in Helsinki. We mainly address following questions: 1. How can we identify the areas that cause most of the traffic in the city? 2. Why there is a urban traffic? Is bus traffic a key cause ...

  5. New Generation Power System for Space Applications

    Science.gov (United States)

    Jones, Loren; Carr, Greg; Deligiannis, Frank; Lam, Barbara; Nelson, Ron; Pantaleon, Jose; Ruiz, Ian; Treicler, John; Wester, Gene; Sauers, Jim; hide

    2004-01-01

    The Deep Space Avionics (DSA) Project is developing a new generation of power system building blocks. Using application specific integrated circuits (ASICs) and power switching modules a scalable power system can be constructed for use on multiple deep space missions including future missions to Mars, comets, Jupiter and its moons. The key developments of the DSA power system effort are five power ASICs and a mod ule for power switching. These components enable a modular and scalab le design approach, which can result in a wide variety of power syste m architectures to meet diverse mission requirements and environments . Each component is radiation hardened to one megarad) total dose. The power switching module can be used for power distribution to regular spacecraft loads, to propulsion valves and actuation of pyrotechnic devices. The number of switching elements per load, pyrotechnic firin gs and valve drivers can be scaled depending on mission needs. Teleme try data is available from the switch module via an I2C data bus. The DSA power system components enable power management and distribution for a variety of power buses and power system architectures employing different types of energy storage and power sources. This paper will describe each power ASIC#s key performance characteristics as well a s recent prototype test results. The power switching module test results will be discussed and will demonstrate its versatility as a multip urpose switch. Finally, the combination of these components will illu strate some of the possible power system architectures achievable fro m small single string systems to large fully redundant systems.

  6. Countermeasures for Developing New Energy Bus Standards in China

    Science.gov (United States)

    Shi, Xin

    2018-01-01

    With the rapid development of new energy vehicle technology, new energy bus has become more and more popular in China, and the relevant standards and policy are urgently needed to guide the market. According to the assessment of the development situation on new energy vehicle technology and new energy bus, combing with traffic policy guidance and the development trend of new energy vehicles, this paper aims to put forward the countermeasures of the new energy bus standard in China, including standard system, key standards and relevant recommendations. Research result is expected to provide decision support for the wide application of new energy bus in China.

  7. Status of the IEEE P896 Future Backplane Bus

    International Nuclear Information System (INIS)

    Gustavson, D.B.

    1983-10-01

    The IEEE P896 Future Backplane Bus project has been influenced by and has influenced FASTBUS and several other contemporary bus designs. This paper summarizes the current status of that project, which is directed toward the needs of modern 32-bit microprocessor systems with multiple processors. Some of the technology developed for P896 will be important for future non-ECL implementations of FASTBUS and other buses. In particular, new bus drivers and receivers should greatly improve the performance and reliability of backplane buses and cable buses. The current status of the P896 serial bus is also summarized

  8. The Software Bus, an Object-Oriented Data Exchange System

    International Nuclear Information System (INIS)

    Akerbaek, T.; Louka, M.

    1996-01-01

    This document describes the Software Bus System, developed for object-oriented task to task communication in a TCP/IP based network. The Software Bus is a set of library functions, developed to be used for the Picasso-3 UIMS, and as a general purpose tool for dynamically interfacing programs at run-time. The Software Bus offers a high level object-oriented data exchange mechanism that relieves the application programmer of the low level TCP/IP-programming and communication protocol handling. The Software Bus is currently available under several UNIX platforms and a version for Windows NT is planned for late 1996. (author)

  9. Foundation field bus in the Spanish nuclear sector; Foundation fieldbus en el sector nuclear espanol

    Energy Technology Data Exchange (ETDEWEB)

    Saez de Montagut Revenga, G.

    2013-07-01

    This paper deals with the modification made in power plants nuclear ASCO 1 and 2 in which scans is the level Control system of Heaters to implementing an Ovation system, as well as the standard Foundation Field bus for field communications. This digitalisation has required a detailed study of the implications on security that could have the centralization of control loops in main feedwater system.

  10. Comparison of PMAC Machines for Starter-Generator Application in a Series Hybrid-Electric Bus

    OpenAIRE

    Sinisa Jurkovic; Elias G. Strangas

    2011-01-01

    This paper presents a comparative study of outer rotor PMAC machine candidates for starter-generator application in hybrid bus with series power train configuration. PMAC machines with interior and surface mount permanent magnets are considered and compared, although a complete analysis is only carried out for the SPM. Different design aspects such as concentrated versus distributed windings as well as interior and exterior rotor structures are evaluated. Different slot numbers per pole per p...

  11. Design, Assembly, Integration, and Testing of a Power Processing Unit for a Cylindrical Hall Thruster, the NORSAT-2 Flatsat, and the Vector Gravimeter for Asteroids Instrument Computer

    Science.gov (United States)

    Svatos, Adam Ladislav

    This thesis describes the author's contributions to three separate projects. The bus of the NORSAT-2 satellite was developed by the Space Flight Laboratory (SFL) for the Norwegian Space Centre (NSC) and Space Norway. The author's contributions to the mission were performing unit tests for the components of all the spacecraft subsystems as well as designing and assembling the flatsat from flight spares. Gedex's Vector Gravimeter for Asteroids (VEGA) is an accelerometer for spacecraft. The author's contributions to this payload were modifying the instrument computer board schematic, designing the printed circuit board, developing and applying test software, and performing thermal acceptance testing of two instrument computer boards. The SFL's cylindrical Hall effect thruster combines the cylindrical configuration for a Hall thruster and uses permanent magnets to achieve miniaturization and low power consumption, respectively. The author's contributions were to design, build, and test an engineering model power processing unit.

  12. Extracting potential bus lines of Customized City Bus Service based on public transport big data

    Science.gov (United States)

    Ren, Yibin; Chen, Ge; Han, Yong; Zheng, Huangcheng

    2016-11-01

    Customized City Bus Service (CCBS) can reduce the traffic congestion and environmental pollution that caused by the increasing in private cars, effectively. This study aims to extract the potential bus lines and each line's passenger density of CCBS by mining the public transport big data. The datasets used in this study are mainly Smart Card Data (SCD) and bus GPS data of Qingdao, China, from October 11th and November 7th 2015. Firstly, we compute the temporal-origin-destination (TOD) of passengers by mining SCD and bus GPS data. Compared with the traditional OD, TOD not only has the spatial location, but also contains the trip's boarding time. Secondly, based on the traditional DBSCAN algorithm, we put forwards an algorithm, named TOD-DBSCAN, combined with the spatial-temporal features of TOD.TOD-DBSCAN is used to cluster the TOD trajectories in peak hours of all working days. Then, we define two variables P and N to describe the possibility and passenger destiny of a potential CCBS line. P is the probability of the CCBS line. And N represents the potential passenger destiny of the line. Lastly, we visualize the potential CCBS lines extracted by our procedure on the map and analyse relationship between potential CCBS lines and the urban spatial structure.

  13. Bus Rapid Transit and Socioeconomic Condition of Bus Commuters in Lagos State

    Directory of Open Access Journals (Sweden)

    Owolabi L. Kuye

    2017-10-01

    Full Text Available Road transport is one of the most common means of transportation across the world. Bus transportation in Nigeria had witnessed many problems for the past decades considering the growing population with the attendant loss of lives and properties in most cities like Lagos in Nigeria. This paper focuses on the adequacy of services provided by Bus Rapid Transit (BRT in Lagos State with respect to the extent to which it influences the socioeconomic conditions of bus commuters. It examines the effect of services rendered by BRT on cost reduction potential, income and safety. Multistage sampling technique was used to select 20 samples each from all respondents in all local government area in Lagos State to reach a total of three hundred and thirty (330 samples. The data collection instrument was the questionnaire which was validated. Data collected were analysed with the use of descriptive statistics such as means, percentages and standard deviation and inferential statistics such as regression and analysis of variance techniques. Findings showed that BRT services has reduced the cost of bus commuters and also increased safety and security thereby increasing the socioeconomic condition of Lagosians. The study recommends improvements in BRT services through the deployment of technology as it had been used in developed countries.

  14. Oracle Service Bus 11g Development Cookbook

    CERN Document Server

    Schmutz, Guido; van Zoggel, Jan

    2012-01-01

    This cookbook is full of immediately useable recipes showing you how to develop service and message-oriented (integration) applications on the Oracle Service Bus. In addition to its cookbook style, which ensures the solutions are presented in a clear step-by-step manner, the explanations go into great detail, which makes it good learning material for everyone who has experience in OSB and wants to improve. Most of the recipes are designed in such a way that each recipe is presented as a separate, standalone entity and reading of prior recipes is not required. The finished solution of each reci

  15. Bus bar joints stability and protection

    CERN Document Server

    Verweij, A

    2009-01-01

    A defective bus connection between two dipole magnets was the primary cause of the incident in sector 34 on September 19th. I will show how this could have happened, i.e. how a highly resistive joint has caused a thermal runaway and burned (or opened) before the QPS threshold was reached. In the second part of the talk I will present the new detection limits for the QPS upgrade of the RB and RQ circuits, required to avoid similar thermal runaways in the future.

  16. Redesign of Transjakarta Bus Driver's Cabin

    Science.gov (United States)

    Mardi Safitri, Dian; Azmi, Nora; Singh, Gurbinder; Astuti, Pudji

    2016-02-01

    Ergonomic risk at work stations with type Seated Work Control was one of the problems faced by Transjakarta bus driver. Currently “Trisakti” type bus, one type of bus that is used by Transjakarta in corridor 9, serving route Pinang Ranti - Pluit, gained many complaints from drivers. From the results of Nordic Body Map questionnaires given to 30 drivers, it was known that drivers feel pain in the neck, arms, hips, and buttocks. Allegedly this was due to the seat position and the button/panel bus has a considerable distance range (1 meter) to be achieved by drivers. In addition, preliminary results of the questionnaire using Workstation Checklist identified their complaints about uncomfortable cushion, driver's seat backrest, and the exact position of the AC is above the driver head. To reduce the risk level of ergonomics, then did research to design the cabin by using a generic approach to designing products. The risk analysis driver posture before the design was done by using Rapid Upper Limb Assessment (RULA), Rapid Entire Body Assessment (REBA), and Quick Exposure Checklist (QEC), while the calculation of the moment the body is done by using software Mannequin Pro V10.2. Furthermore, the design of generic products was done through the stages: need metric-matrix, house of quality, anthropometric data collection, classification tree concept, concept screening, scoring concept, design and manufacture of products in the form of two-dimensional. While the design after design risk analysis driver posture was done by using RULA, REBA, and calculation of moments body as well as the design visualized using software 3DMax. From the results of analysis before the draft design improvements cabin RULA obtained scores of 6, REBA 9, and the result amounted to 57.38% QEC and moment forces on the back is 247.3 LbF.inch and on the right hip is 72.9 LbF.in. While the results of the proposed improvements cabin design RULA obtained scores of 3, REBA 4, and the moment of force on

  17. Methods of computing steady-state voltage stability margins of power systems

    Science.gov (United States)

    Chow, Joe Hong; Ghiocel, Scott Gordon

    2018-03-20

    In steady-state voltage stability analysis, as load increases toward a maximum, conventional Newton-Raphson power flow Jacobian matrix becomes increasingly ill-conditioned so power flow fails to converge before reaching maximum loading. A method to directly eliminate this singularity reformulates the power flow problem by introducing an AQ bus with specified bus angle and reactive power consumption of a load bus. For steady-state voltage stability analysis, the angle separation between the swing bus and AQ bus can be varied to control power transfer to the load, rather than specifying the load power itself. For an AQ bus, the power flow formulation is only made up of a reactive power equation, thus reducing the size of the Jacobian matrix by one. This reduced Jacobian matrix is nonsingular at the critical voltage point, eliminating a major difficulty in voltage stability analysis for power system operations.

  18. Potential of greenhouse gas emission reduction in Thai road transport by ethanol bus technology

    International Nuclear Information System (INIS)

    Chollacoop, Nuwong; Saisirirat, Peerawat; Sukkasi, Sittha; Tongroon, Manida; Fukuda, Tuenjai; Fukuda, Atsushi; Nivitchanyong, Siriluck

    2013-01-01

    Highlights: ► Energy demand modeling in Thai road transportation sector was developed. ► Such model was used to assess environment impact by ethanol bus technology (ED95). ► Ethanol bus technology (ED95) shows beneficial impacts to Thailand. ► Increase in ethanol demand and decrease in GHG emission in Thailand by ethanol bus. ► Ethanol bus (ED95) has been successfully demonstrated in Thailand. -- Abstract: Over decades, Thailand energy consumption has been concentrated in three main sectors, namely manufacturing, power and transportation. Energy consumption in transportation sector has also been dominated by road transport due to limited coverage by rail and water transportation. Hence, road transport has been a major contributor for greenhouse gas emission in Thailand over recent years. Along with global warming concern throughout the world, Thailand has taken various adaptation and mitigation measures, especially the strong policy push to use carbon–neutral biofuel in transportation sector due to Thailand competitive advantage in agriculture sector. National Renewable Energy Plan (2008–2022) has set challenging targets of 9 and 4.5 million liters/day of ethanol and biodiesel consumption by 2022, respectively. Various blends of ethanol in gasoline (10%, 20% and 85%) and biodiesel in diesel (up to 5%) have been commercially available. However, since current consumption of diesel is twice as much of gasoline, ethanol blend in gasoline would widen the imbalance consumption of gasoline and diesel. The present study however offers an insight into a possibility to use ethanol as diesel substitute. A case study of ethanol bus technology was investigated by recourse to energy demand modeling. Necessary data, such as a number of vehicles (NVs) for various vehicle types, vehicle kilometer of travel (VKT) and fuel economy (FE) were collected, with reasonable assumptions made for those unavailable data, to construct predicative energy demand model. Scenario

  19. Power source facility

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kazuhiro; Kinoshita, Shoichiro

    1998-09-29

    The present invention concerns a power plant, in which power is supplied from an ordinary system battery to an ordinary DC bus system when all of the AC power sources should be lost and a generator is driven by a steam turbine. A generator is connected with an ordinary system battery charger by way of a channel. If all of power sources should be lost, the ordinary system battery charger is driven by using emergency steam turbine generator facilities, and reactor steams are supplied thereby enabling to supply power to the ordinary system DC bus system for a long period of time. (N.H.)

  20. A Conceptual Approach for Optimising Bus Stop Spacing

    Science.gov (United States)

    Johar, Amita; Jain, S. S.; Garg, P. k.

    2017-06-01

    An efficient public transportation system is essential of any country. The growth, development and shape of the urban areas are mainly due to availability of good transportation (Shah et al. in Inst Town Plan India J 5(3):50-59, 1). In developing countries, like India, travel by local bus in a city is very common. The accidents, congestion, pollution and appropriate location of bus stops are the major problems arising in metropolitan cities. Among all the metropolitan cities in India, Delhi has highest percentage of growth of population and vehicles. Therefore, it is important to adopt efficient and effective ways to improve mobility in different metropolitan cities in order to overcome the problem and to reduce the number of private vehicles on the road. The primary objective of this paper is to present a methodology for developing a model for optimum bus stop spacing (OBSS). It describes the evaluation of existing urban bus route, data collection, development of model for optimizing urban bus route and application of model. In this work, the bus passenger generalized cost method is used to optimize the spacing between bus stops. For the development of model, a computer program is required to be written. The applicability of the model has been evaluated by taking the data of urban bus route of Delhi Transport Corporation (DTC) in Excel sheet in first phase. Later on, it is proposed to develop a programming in C++ language. The developed model is expected to be useful to transport planner for rational design of the spacing of bus stops to save travel time and to generalize operating cost. After analysis it is found that spacing between the bus stop comes out to be between 250 and 500 m. The Proposed Spacing of bus stops is done considering the points that they don't come nearer to metro/rail station, entry or exit of flyover and near traffic signal.

  1. Spacecraft exploration of asteroids

    International Nuclear Information System (INIS)

    Veverka, J.; Langevin, Y.; Farquhar, R.; Fulchignoni, M.

    1989-01-01

    After two decades of spacecraft exploration, we still await the first direct investigation of an asteroid. This paper describes how a growing international interest in the solar system's more primitive bodies should remedy this. Plans are under way in Europe for a dedicated asteroid mission (Vesta) which will include multiple flybys with in situ penetrator studies. Possible targets include 4 Vesta, 8 Flora and 46 Hestia; launch its scheduled for 1994 or 1996. In the United States, NASA plans include flybys of asteroids en route to outer solar system targets

  2. Spacecraft rendezvous and docking

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...

  3. Toward autonomous spacecraft

    Science.gov (United States)

    Fogel, L. J.; Calabrese, P. G.; Walsh, M. J.; Owens, A. J.

    1982-01-01

    Ways in which autonomous behavior of spacecraft can be extended to treat situations wherein a closed loop control by a human may not be appropriate or even possible are explored. Predictive models that minimize mean least squared error and arbitrary cost functions are discussed. A methodology for extracting cyclic components for an arbitrary environment with respect to usual and arbitrary criteria is developed. An approach to prediction and control based on evolutionary programming is outlined. A computer program capable of predicting time series is presented. A design of a control system for a robotic dense with partially unknown physical properties is presented.

  4. Interfacing the septa movement (DC motors) equipment to the PS control system and the MIL1553 bus

    CERN Document Server

    Dehavay, Claude

    1995-01-01

    Continuing the rejuvenation of the PS Control system , this application replaces the Single Transceiver Hybrid used to interface the Septa Movement Fquipment by a G64 system connected to the VME crate via the MIL1553 bus. This note explains the G64 hardware interface and details the standard message as defined in the Control Protocole for Power Converter, RF and Stepping Motor equipment.

  5. MIDN: A spacecraft Micro-dosimeter mission

    International Nuclear Information System (INIS)

    Pisacane, V. L.; Ziegler, J. F.; Nelson, M. E.; Caylor, M.; Flake, D.; Heyen, L.; Youngborg, E.; Rosenfeld, A. B.; Cucinotta, F.; Zaider, M.; Dicello, J. F.

    2006-01-01

    MIDN (Micro-dosimetry instrument) is a payload on the MidSTAR-I spacecraft (Midshipman Space Technology Applications Research) under development at the United States Naval Academy. MIDN is a solid-state system being designed and constructed to measure Micro-dosimetric spectra to determine radiation quality factors for space environments. Radiation is a critical threat to the health of astronauts and to the success of missions in low-Earth orbit and space exploration. The system will consist of three separate sensors, one external to the spacecraft, one internal and one embedded in polyethylene. Design goals are mass <3 kg and power <2 W. The MidSTAR-I mission in 2006 will provide an opportunity to evaluate a preliminary version of this system. Its low power and mass makes it useful for the International Space Station and manned and unmanned interplanetary missions as a real-time system to assess and alert astronauts to enhanced radiation environments. (authors)

  6. Assessment on the occupational exposure of urban public bus drivers to bioaccessible trace metals through resuspended fraction of settled bus dust

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Peng [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 (United States); Liu, Sa [Environmental Health Sciences Division, School of Public Health, University of California, Berkeley, CA, 94720-7360 (United States); Ye, Wenyuan [Department of Chemical Engineering, KU Leuven, Willem de Croylaan 46, B-3001 Heverlee (Belgium); Lin, Nan; Meng, Ping [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Feng, Yujie, E-mail: yujief@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Zhang, Zhaohan; Cui, Fuyi; Lu, Binyu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Xing, Baoshan [Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 (United States)

    2015-03-01

    Limited information is available on the bioaccessible fraction of trace metals in the resuspended fraction of settled bus dust in order to estimate bus drivers ' occupational exposure. In this study, 45 resuspended fraction of settled dust samples were collected from gasoline and compressed natural gas (CNG) powered buses and analyzed for trace metals and their fraction concentrations using a three-step sequential extraction procedure. Experimental results showed that zinc (Zn) had the greatest bioaccessible fraction, recorded as an average of 608.53 mg/kg, followed in order of decreasing concentration by 129.80 mg/kg lead (Pb), 56.77 mg/kg copper (Cu), 34.03 mg/kg chromium (Cr), 22.05 mg/kg nickel (Ni), 13.17 mg/kg arsenic (As) and 2.77 mg/kg cadmium (Cd). Among the three settled bus dust exposure pathways, ingestion was the main route. Total exposure hazard index (HIt) for non-carcinogenic effect trace metals was lower than the safety level of 1. The incremental lifetime cancer risk (ILCR) for drivers was estimated for trace metal exposure. Pb and Ni presented relatively high potential risks in the non-carcinogenic and potentially carcinogenic health assessment for all drivers. ILCR was in the range of 1.84E − 05 to 7.37E − 05 and 1.74E − 05 to 6.95E − 05 for gasoline and CNG buses, respectively. - Highlights: • As, Cd and Ni had relatively higher bioaccessibility and mobility in the resuspended fraction of settled bus dust. • Bioaccessible metal concentrations were higher in gasoline-fueled buses than those in CNG-fueled buses. • The carcinogenic risk probabilities to drivers were around the acceptable level.

  7. Schedule and complex motion of shuttle bus induced by periodic inflow of passengers

    Science.gov (United States)

    Nagatani, Takashi; Naito, Yuichi

    2011-09-01

    We have studied the dynamic behavior of a bus in the shuttle bus transportation with a periodic inflow. A bus schedule is closely related to the dynamics. We present the modified circle map model for the dynamics of the shuttle bus. The motion of the shuttle bus depends on the loading parameter and the inflow period. The shuttle bus displays the periodic, quasi-periodic, and chaotic motions with varying both loading parameter and inflow rate.

  8. Illinois School Bus Driver Instructional Program. Trainee Guide. Revised.

    Science.gov (United States)

    Illinois State Board of Education, Springfield.

    This trainee guide contains six units of materials for use by those studying to become school bus drivers in the State of Illinois. Covered in the units are the following topics: school bus driver role and responsibility, passenger control, first aid, driving fundamentals, accidents and emergencies, and detecting hazards. Each unit contains a…

  9. Connecticut nutmeg fuel cell bus project : first analysis report.

    Science.gov (United States)

    2012-07-01

    This report summarizes the experience and early results from a fuel cell bus demonstration funded by the Federal Transit Administra-tion (FTA) under the National Fuel Cell Bus Program (NFCBP). A team led by the Northeast Advanced Vehicle Consortium a...

  10. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2008-10-01

    This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.

  11. 3D reconstructions of a controlled bus bombing

    DEFF Research Database (Denmark)

    Villa, Chiara; Hansen, Nikolaj Friis; Hansen, Kamilla Maria

    2018-01-01

    Objectives: to demonstrate the usefulness of 3D reconstructions to better understand the dynamic of a controlled bus bombing. Materials and methods: 3D models of the victims (pigs) were created from post-mortem CT scanning using Mimic software; 3D models of the crime scene (bus) were generated by...

  12. Review of bus drivers' occupational stress and stress prevention

    NARCIS (Netherlands)

    Kompier, M.A.J.; Di Martino, V.

    1995-01-01

    Although heterogeneous in methodology and content, 32 studies from 13 countries on bus drivers' work and health are similar in their conclusions. Bus-driving–characterized by high demands, low control and low support – can be regarded as a classic example of high-strain occupation, with high risks

  13. 32 CFR 935.138 - Motor bus operation.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Motor bus operation. 935.138 Section 935.138 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE TERRITORIAL AND INSULAR REGULATIONS WAKE ISLAND CODE Motor Vehicle Code § 935.138 Motor bus operation. Each person operating a motor...

  14. Bus Lifecycle Cost Model for Federal Land Management Agencies.

    Science.gov (United States)

    2011-09-30

    The Bus Lifecycle Cost Model is a spreadsheet-based planning tool that estimates capital, operating, and maintenance costs for various bus types over the full lifecycle of the vehicle. The model is based on a number of operating characteristics, incl...

  15. Wheel speed management control system for spacecraft

    Science.gov (United States)

    Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

    1991-01-01

    A spacecraft attitude control system uses at least four reaction wheels. In order to minimize reaction wheel speed and therefore power, a wheel speed management system is provided. The management system monitors the wheel speeds and generates a wheel speed error vector. The error vector is integrated, and the error vector and its integral are combined to form a correction vector. The correction vector is summed with the attitude control torque command signals for driving the reaction wheels.

  16. Low cost spacecraft computers: Oxymoron or future trend?

    Science.gov (United States)

    Manning, Robert M.

    1993-01-01

    Over the last few decades, application of current terrestrial computer technology in embedded spacecraft control systems has been expensive and wrought with many technical challenges. These challenges have centered on overcoming the extreme environmental constraints (protons, neutrons, gamma radiation, cosmic rays, temperature, vibration, etc.) that often preclude direct use of commercial off-the-shelf computer technology. Reliability, fault tolerance and power have also greatly constrained the selection of spacecraft control system computers. More recently, new constraints are being felt, cost and mass in particular, that have again narrowed the degrees of freedom spacecraft designers once enjoyed. This paper discusses these challenges, how they were previously overcome, how future trends in commercial computer technology will simplify (or hinder) selection of computer technology for spacecraft control applications, and what spacecraft electronic system designers can do now to circumvent them.

  17. Sustainable transport and the organisation of bus services in Manchester

    DEFF Research Database (Denmark)

    Gudmundsson, Henrik; Sørensen, Claus Hedegaard

    2008-01-01

    alternative modes of transport to private cars, such as public transport. In this paper we focus only on the potential of bus transport services in cities for attracting travellers from cars. It is a basic assumption behind this paper that the ability of public bus transport to attract travellers from cars...... depends on how the bus sector is organised. By organisation we adopt an institutional point of view and consider basic modes of governance. Basic modes of governance include the forms “market”, “hierarchy” and “network” (Powell 1990). So-called New Public Management (NPM) reforms have changed the modes...... of governance of bus transport in several countries, including Denmark and the United Kingdom. Our focus is on how New Public Mangement Reforms have changed the mix of governance modes and thus may have influenced the ability of urban bus transport to attract travellers from cars. We focus on a particular case...

  18. SISTEM RESERVASI TIKET BUS DI TERMINAL ARJOSARI MALANG

    Directory of Open Access Journals (Sweden)

    Surya Wirawan

    2013-10-01

    Full Text Available Bus Ticket Reservation System is an application that can be used to help booking bus tickets and the buyer will get a report via SMS Gateway. The reservation system is made by conducting field studies in Arjosari Bus Station Malang. This system uses SMS Gateway to send the report to the buyer after booking bus tickets online. SMS Gateway on this application serves as a liaison which delays sms between External Short Message entitiy (ESME and Short Message Service Center (SMSC and so does in reserve.The reservation system made is developed with the PHP programming language and has a prototype system pattern. System functions were tested using the validation testing, performance testing, and usability testing. The results percentage of responses usability testing is 67.7%. This shows that Ticket Reservation System at Arjosari Bus Station can be used well enough.

  19. Research on the Coordinated Design of Bus and Taxi Station

    Directory of Open Access Journals (Sweden)

    Jiangfeng Xi

    2015-01-01

    Full Text Available Rises in the number of transit buses, bus routes, and overall traffic volume in China’s cities, coupled with interference from other transport modes, such as taxis loading and unloading passengers nearby, have led to increasing traffic delays at bus stops, which is considered one of the factors degrading service levels and traffic operations on urban roadways. This paper studies traffic characteristics at bus stops, investigates variations in delay from different types or designs of bus stops, and analyzes the impact of it on traffic capacity, the purpose of which is to propose a solution to predicting the feasibility of an integrated design of bus stops and taxi stands with the help of mathematical models and based on the objectives of optimal traffic operations and passenger transfer.

  20. Improved design of HIRFL-CSR EVME bus controller

    International Nuclear Information System (INIS)

    Zhao Long; Liu Wufeng; Qiao Weimin; Jing Lan

    2009-01-01

    The EVME bus controller which is a key component of the HIRFL-CSR control system was improved. Besides reconfiguring the embedded Linux, a utility program was developed for data exchange between the controller and the database. The bus controller is based on ARM920T(ARM9) micro processor which is BGA packaged. The bus controller has the universal interface of VGA display, keyboard, and mouse. The backboard interface logic is programmed in an in-system configurable FPGA device. The bus can drive high current up to 64 mA, with the flexibility of the programmable signal definitions. All the improved performance helped the EVME bus controller play a crucial role in HIRFL-CSR control system. (authors)

  1. Performance Improvement for Two-Stage Single-Phase Grid-Connected Converters Using a Fast DC Bus Control Scheme and a Novel Synchronous Frame Current Controller

    Directory of Open Access Journals (Sweden)

    Bingzhang Li

    2017-03-01

    Full Text Available Two-stage single-phase grid-connected converters are widely used in renewable energy applications. Due to the presence of a second harmonic ripple across the DC bus voltage, it is very challenging to design the DC bus voltage control scheme in single-phase grid-connected inverters. The DC bus voltage controller must filter the ripple and balance a tradeoff between low harmonic distortion and high bandwidth. This paper presents a fast DC bus voltage controller, which uses a second order digital finite impulse response (FIR notch filter in conjunction with input power feedforward scheme to ensure the steady-state and dynamic performance. To gain the input power without extra hardware, a Kalman filter is incorporated to estimate the DC bus input current. At the same time, a modulation compensation strategy is implemented to eliminate the nonlinearity of the grid current control loop, which is caused by the DC bus voltage ripple. Moreover, a novel synchronous frame current controller for single-phase systems is also introduced, and its equivalent model in stationary frame has been derived. Simulation and experimental results are provided to verify the effective of the proposed control scheme.

  2. Development and Commissioning Results of the Hybrid Sensor Bus Engineering Qualification Model

    Science.gov (United States)

    Hurni, Andreas; Putzer, Phillipp; Roner, Markus; Gurster, Markus; Hulsemeyer, Christian; Lemke, Norbert M. K.

    2016-08-01

    In order to reduce mass, AIT effort and overall costs of classical point-to-point wired temperature sensor harness on-board spacecraft OHB System AGhas introduced the Hybrid Sensor Bus (HSB) system which interrogates sensors connected in a bus architecture. To use the advantages of electrical as wellas of fiber-optical sensing technologies, HSB is designed as a modular measurement system interrogating digital sensors connected on electricalsensor buses based on I2C and fiber-optical sensor buses based on fiber Bragg grating (FBG) sensors inscribed in optical fibers. Fiber-optical sensor bus networks on-board satellites are well suited for temperature measurement due to low mass, electro-magnetic insensitivity and the capability to embed them inside structure parts. The lightweight FBG sensors inscribed in radiation tolerant fibers can reach every part of the satellite. HSB has been developed in the frame of the ESA ARTES program with European and German co- funding and will be verified as flight demonstrator on- board the German Heinrich Hertz satellite (H2Sat).In this paper the Engineering Qualification Model (EQM) development of HSB and first commissioning results are presented. For the HSB development requirements applicable for telecommunication satellite platforms have been considered. This includes an operation of at least 15 years in a geostationary orbit.In Q3/2016 the qualification test campaign is planned to be carried out. The HSB EQM undergoes a full qualification according to ECSS. The paper concludes with an outlook regarding this HSB flight demonstrator development and its in-orbit verification (IOV) on board H2Sat.

  3. Standardization and Economics of Nuclear Spacecraft, Final Report, Phase I, Sense Study

    Energy Technology Data Exchange (ETDEWEB)

    1973-03-01

    Feasibility and cost benefits of nuclear-powered standardized spacecraft are investigated. The study indicates that two shuttle-launched nuclear-powered spacecraft should be able to serve the majority of unmanned NASA missions anticipated for the 1980's. The standard spacecraft include structure, thermal control, power, attitude control, some propulsion capability and tracking, telemetry, and command subsystems. One spacecraft design, powered by the radioisotope thermoelectric generator, can serve missions requiring up to 450 watts. The other spacecraft design, powered by similar nuclear heat sources in a Brayton-cycle generator, can serve missions requiring up to 21000 watts. Design concepts and trade-offs are discussed. The conceptual designs selected are presented and successfully tested against a variety of missions. The thermal design is such that both spacecraft are capable of operating in any earth orbit and any orientation without modification. Three-axis stabilization is included. Several spacecraft can be stacked in the shuttle payload compartment for multi-mission launches. A reactor-powered thermoelectric generator system, operating at an electric power level of 5000 watts, is briefly studied for applicability to two test missions of divers requirements. A cost analysis indicates that use of the two standardized spacecraft offers sizable savings in comparison with specially designed solar-powered spacecraft. There is a duplicate copy.

  4. Work fatigue in urban bus drivers

    Directory of Open Access Journals (Sweden)

    Teresa Makowiec-Dąbrowska

    2015-10-01

    Full Text Available Background: Bus drivers are a special group of professional drivers who are at a very high risk of fatigue. The aim of the study was to examine whether the driver’s subjective assessment of fatigue allows for the determination of its level and identification of its causes. Material and Methods: The study group comprised 45 randomly selected bus drivers (mean age – 43.7±7.9 years, period of employment as drivers – 14.7±8.6 years. Examinations were performed in all subjects four times – before and after work on the “easy” route (outside the city center, small traffic intensity and before and after work on the “difficult” route (city center, heavy traffic. The fatigue test questionnaire, based on the list of symptoms of fatigue prepared by the Japan Research Committee of Fatigue, was used in the study. Results: The rating of fatigue after the work was significantly higher than that before the work. The profile of fatigue after work was not influenced by the type of route, but the assessment of most symptoms of fatigue reached a higher level after the “difficult” routes and the differences were statistically significant for 7 symptoms. Only the ratings of leg fatigue, feeling of heaviness, and the necessity to squint eyes and gaze with effort reached the higher levels after driving the “easy” routes. It has been found that the level of fatigue was significantly correlated with the job characteristics (driving time, the length of the route, number of stops, etc. and with the abundance of food ingested and type of beverage (coffee vs. others drunk prior to driving. Conclusions: The questionnaire used in our study to assess the subjective feeling of fatigue has proved to be a sensitive and useful tool for indicating the level and causes of fatigue. The relationship between the symptoms of fatigue and the characteristics of job and lifestyle shows that actions must be taken by both the employers and employees to prevent fatigue

  5. Solar Array Power Conditioning for a Spinning Satellite

    Science.gov (United States)

    De Luca, Antonio; Chirulli, Giovanni

    2008-09-01

    The conditioning of the output power from a solar array can mainly be achieved by the adoption of DET or MPPT based architecture. There are several factors that can orientate the choice of the system designer towards one solution or the other; some of them maybe inherent to the mission derived requirements (Illumination levels, EMC cleanliness, etc.), others come directly from a careful assessment of performances and losses of both power conditioner and solar array.Definition of the criteria on which basis the final choice is justified is important as they have to guarantee a clear determination of the available versus the required power in all those mission conditions identifiable as design drivers for the overall satellite system both in terms of mass and costs.Such criteria cannot just be simple theoretical enunciations of principles; nor the meticulous definition of them on a case by case basis for different types of missions as neither option gives a guarantee of being conclusive.The aim of this paper is then to suggest assessment steps and guidelines that can be considered generically valid for any mission case, starting from the exposition of the trade off activity performed in order to choose the power conditioning solution for a spinning satellite having unregulated power bus architecture. Calculations and numerical simulations have been made in order to establish the needed solar array surface in case of adoption of a DET or MPPT solution, taking into account temperature and illumination levels on the solar cells, as well as power losses and inefficiencies from the solar generator to the main power bus, in different mission phases. Particular attention has been taken in order to correctly evaluate the thermal effects on the rest of the spacecraft as function of the adopted power system regulation.

  6. Design feasibility via ascent optimality for next-generation spacecraft

    Science.gov (United States)

    Miele, A.; Mancuso, S.

    This paper deals with the optimization of the ascent trajectories for single-stage-sub-orbit (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem is studied for different values of the engine specific impulse and spacecraft structural factor. The main conclusions are that: feasibility of SSSO spacecraft is guaranteed for all the parameter combinations considered; feasibility of SSTO spacecraft depends strongly on the parameter combination chosen; not only feasibility of TSTO spacecraft is guaranteed for all the parameter combinations considered, but the TSTO payload is several times the SSTO payload. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, aerodynamic improvements do not yield significant improvements in payload. For SSSO, SSTO, and TSTO spacecraft, simple engineering approximations are developed connecting the maximum payload weight to the engine specific impulse and spacecraft structural factor. With reference to the specific impulse/structural factor domain, these engineering approximations lead to the construction of zero-payload lines separating the feasibility region (positive payload) from the unfeasibility region (negative payload).

  7. Bus Based Synchronization Method for CHIPPER Based NoC

    Directory of Open Access Journals (Sweden)

    D. Muralidharan

    2016-01-01

    Full Text Available Network on Chip (NoC reduces the communication delay of System on Chip (SoC. The main limitation of NoC is power consumption and area overhead. Bufferless NoC reduces the area complexity and power consumption by eliminating buffers in the traditional routers. The bufferless NoC design should include live lock freeness since they use hot potato routing. This increases the complexity of bufferless NoC design. Among the available propositions to reduce this complexity, CHIPPER based bufferless NoC is considered as one of the best options. Live lock freeness is provided in CHIPPER through golden epoch and golden packet. All routers follow some synchronization method to identify a golden packet. Clock based method is intuitively followed for synchronization in CHIPPER based NoCs. It is shown in this work that the worst-case latency of packets is unbearably high when the above synchronization is followed. To alleviate this problem, broadcast bus NoC (BBus NoC approach is proposed in this work. The proposed method decreases the worst-case latency of packets by increasing the golden epoch rate of CHIPPER.

  8. The Wheels on the Bus Go “Buy Buy Buy”: School Bus Advertising Laws

    Science.gov (United States)

    2012-01-01

    School buses, a practical necessity for millions of children, are at the center of new efforts to raise revenue. School bus advertising laws bring public health and commercialization concerns to the school setting. In doing so, they potentially expose school districts to First Amendment lawsuits. I examined various school bus advertising bills and laws. I reviewed First Amendment “forum analysis” as applied in the transit and school settings to clarify how this legal test may affect school districts subject to such laws. I have made recommendations for school districts to enact appropriate policies to ensure that such advertising does not undermine public health and to enable the districts to maintain control over their property. PMID:22742065

  9. The wheels on the bus go "buy buy buy": school bus advertising laws.

    Science.gov (United States)

    Pomeranz, Jennifer L

    2012-09-01

    School buses, a practical necessity for millions of children, are at the center of new efforts to raise revenue. School bus advertising laws bring public health and commercialization concerns to the school setting. In doing so, they potentially expose school districts to First Amendment lawsuits. I examined various school bus advertising bills and laws. I reviewed First Amendment "forum analysis" as applied in the transit and school settings to clarify how this legal test may affect school districts subject to such laws. I have made recommendations for school districts to enact appropriate policies to ensure that such advertising does not undermine public health and to enable the districts to maintain control over their property.

  10. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Science.gov (United States)

    Goh, Segun; Lee, Keumsook; Choi, Moo Young; Fortin, Jean-Yves

    2014-01-01

    Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare) bus stops are transformed into a (renormalized) "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  11. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Directory of Open Access Journals (Sweden)

    Segun Goh

    Full Text Available Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare bus stops are transformed into a (renormalized "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  12. Aircraft, ships, spacecraft, nuclear plants and quality

    International Nuclear Information System (INIS)

    Patrick, M.G.

    1984-05-01

    A few quality assurance programs outside the purview of the Nuclear Regulatory Commission were studied to identify features or practices which the NRC could use to enhance its program for assuring quality in the design and construction of nuclear power plants. The programs selected were: the manufacture of large commercial transport aircraft, regulated by the Federal Aviation Administration; US Navy shipbuilding; commercial shipbuilding regulated by the Maritime Administration and the US Coast Guard; Government-owned nuclear plants under the Department of Energy; spacecraft under the National Aeronautics and Space Administration; and the construction of nuclear power plants in Canada, West Germany, France, Japan, Sweden, and the United Kingdom

  13. Assessing Bus Performance Rating in Kajang, Selangor

    Science.gov (United States)

    Norhisham, S.; Ismail, A.; Sidek, L. M.; Borhan, M. N.; Zaini, N.; Yen, A. T. G.

    2018-04-01

    The Transit Capacity and Quality of Service Manual (TCQSM) was chosen based on the review with four manuals and guidelines for the method will be applied. Six (6) attributes, namely Hours of Service, Passenger Load, Transit Auto Travel Time, Service Frequency, Punctuality Performance and Service Coverage were chosen for evaluation.[6][7][8]. A total of three (3) operators with seven (7) routes were identified in Kajang. Based on the final results, the Quality of Service (QOS) findings was rated as D, which was regarded as minimum or satisfactory. Most stakeholders’ recommendations were: for the operators to provide information on bus scheduling and have accurate information for the passengers. It was suggested that in future this study can be extended to all routes and could be repeated after the opening of the Mass Rapid Transit (MRT) stations in Kajang, so as to provide a comparison and better evaluation of the public buses in Kajang.

  14. Bus bar electrical feedthrough for electrorefiner system

    Science.gov (United States)

    Williamson, Mark; Wiedmeyer, Stanley G; Willit, James L; Barnes, Laurel A; Blaskovitz, Robert J

    2013-12-03

    A bus bar electrical feedthrough for an electrorefiner system may include a retaining plate, electrical isolator, and/or contact block. The retaining plate may include a central opening. The electrical isolator may include a top portion, a base portion, and a slot extending through the top and base portions. The top portion of the electrical isolator may be configured to extend through the central opening of the retaining plate. The contact block may include an upper section, a lower section, and a ridge separating the upper and lower sections. The upper section of the contact block may be configured to extend through the slot of the electrical isolator and the central opening of the retaining plate. Accordingly, relatively high electrical currents may be transferred into a glovebox or hot-cell facility at a relatively low cost and higher amperage capacity without sacrificing atmosphere integrity.

  15. Field bus technology in accelerator control systems

    International Nuclear Information System (INIS)

    Tang Shuming

    1999-01-01

    Since eighties to now, the computer technology, network communication and ULSI technology have been developing rapidly. The level of control for industries and scientific experiments has been upgraded accordingly, so as to meet the increasing requirements for automation. The control systems become more complicated; the devices in control systems become more and more intelligent. However the cost of DCS (Distributed Control System) is quite expensive and the period of system integration is very long. More than ten measurement results for two methods defined in the world, in order to get inter operability of intelligent devices and reduce the costs. The author presents the development trend of fieldbuses briefly and describes the main performances of CAN, LONWORKS, WOLDFIP and PROFIBUS which are mainly used in the world today. The author proposes that the field bus technology will be introduced into the accelerator control systems in the country

  16. Advanced Stirling Convertor Dual Convertor Controller Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

    Science.gov (United States)

    Dugala, Gina M.; Taylor, Linda M.; Bell, Mark E.; Dolce, James L.; Fraeman, Martin; Frankford, David P.

    2015-01-01

    NASA Glenn Research Center developed a nonnuclear representation of a Radioisotope Power System (RPS) consisting of a pair of Advanced Stirling Convertors (ASCs), Dual Convertor Controller (DCC) EMs (engineering models) 2 and 3, and associated support equipment, which were tested in the Radioisotope Power Systems System Integration Laboratory (RSIL). The DCC was designed by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) to actively control a pair of ASCs. The first phase of testing included a Dual Advanced Stirling Convertor Simulator (DASCS), which was developed by JHU/APL and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. RSIL provides insight into the electrical interactions between a representative radioisotope power generator, its associated control schemes, and realistic electric system loads. The first phase of integration testing included the following spacecraft bus configurations: capacitive, battery, and super-capacitor. A load profile, created based on data from several missions, tested the RPS's and RSIL's ability to maintain operation during load demands above and below the power provided by the RPS. The integration testing also confirmed the DCC's ability to disconnect from the spacecraft when the bus voltage dipped below 22 volts or exceeded 36 volts. Once operation was verified with the DASCS, the tests were repeated with actual operating ASCs. The goal of this integration testing was to verify operation of the DCC when connected to a spacecraft and to verify the functionality of the newly designed RSIL. The results of these tests are presented in this paper.

  17. Task Analysis Assessment on Intrastate Bus Traffic Controllers

    Science.gov (United States)

    Yen Bin, Teo; Azlis-Sani, Jalil; Nur Annuar Mohd Yunos, Muhammad; Ismail, S. M. Sabri S. M.; Tajedi, Noor Aqilah Ahmad

    2016-11-01

    Public transportation acts as social mobility and caters the daily needs of the society for passengers to travel from one place to another. This is true for a country like Malaysia where international trade has been growing significantly over the past few decades. Task analysis assessment was conducted with the consideration of cognitive ergonomic view towards problem related to human factors. Conducting research regarding the task analysis on bus traffic controllers had allowed a better understanding regarding the nature of work and the overall monitoring activities of the bus services. This paper served to study the task analysis assessment on intrastate bus traffic controllers and the objectives of this study include to conduct task analysis assessment on the bus traffic controllers. Task analysis assessment for the bus traffic controllers was developed via Hierarchical Task Analysis (HTA). There are a total of five subsidiary tasks on level one and only two were able to be further broken down in level two. Development of HTA allowed a better understanding regarding the work and this could further ease the evaluation of the tasks conducted by the bus traffic controllers. Thus, human error could be reduced for the safety of all passengers and increase the overall efficiency of the system. Besides, it could assist in improving the operation of the bus traffic controllers by modelling or synthesizing the existing tasks if necessary.

  18. Small Spacecraft for Planetary Science

    Science.gov (United States)

    Baker, John; Castillo-Rogez, Julie; Bousquet, Pierre-W.; Vane, Gregg; Komarek, Tomas; Klesh, Andrew

    2016-07-01

    As planetary science continues to explore new and remote regions of the Solar system with comprehensive and more sophisticated payloads, small spacecraft offer the possibility for focused and more affordable science investigations. These small spacecraft or micro spacecraft (attitude control and determination, capable computer and data handling, and navigation are being met by technologies currently under development to be flown on CubeSats within the next five years. This paper will discuss how micro spacecraft offer an attractive alternative to accomplish specific science and technology goals and what relevant technologies are needed for these these types of spacecraft. Acknowledgements: Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to NASA. Government sponsorship acknowledged.

  19. DWPF Melter No.2 Prototype Bus Bar Test Report

    International Nuclear Information System (INIS)

    Gordon, J.

    2003-01-01

    Characterization and performance testing of a prototype DWPF Melter No.2 Dome Heater Bus Bar are described. The prototype bus bar was designed to address the design features of the existing system which may have contributed to water leaks on Melter No.1. Performance testing of the prototype revealed significant improvement over the existing design in reduction of both bus bar and heater connection maximum temperature, while characterization revealed a few minor design and manufacturing flaws in the bar. The prototype is recommended as an improvement over the existing design. Recommendations are also made in the area of quality control to ensure that critical design requirements are met

  20. Using microcomputers for lighting appliance control using a DALI bus

    Directory of Open Access Journals (Sweden)

    Sysala Tomas

    2016-01-01

    Full Text Available Article concerns the DALI bus theoretical and practical aspects. The DALI bus is a modern technology developed especially for illumination systems control. Authors are outlining communication basic principles related to the physical layer and going up to more complex data transactions among particular devices. The article main topic is aimed at two device models development based on microcontroller and exploiting that technology. The first of those two devices is a DALI slave unit enabling the light source or multi switch with light indication components control via DALI bus. The second device measures the ambient illumination intensity and it also detects errors in the load.

  1. Printed Spacecraft Separation System

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R [ORNL; Holmans, Walter [Planetary Systems Corporation

    2016-10-01

    In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly into a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.

  2. Spectra and spacecraft

    Science.gov (United States)

    Moroz, V. I.

    2001-02-01

    In June 1999, Dr. Regis Courtin, Associate Editor of PSS, suggested that I write an article for the new section of this journal: "Planetary Pioneers". I hesitated , but decided to try. One of the reasons for my doubts was my primitive English, so I owe the reader an apology for this in advance. Writing took me much more time than I supposed initially, I have stopped and again returned to manuscript many times. My professional life may be divided into three main phases: pioneering work in ground-based IR astronomy with an emphasis on planetary spectroscopy (1955-1970), studies of the planets with spacecraft (1970-1989), and attempts to proceed with this work in difficult times. I moved ahead using the known method of trials and errors as most of us do. In fact, only a small percentage of efforts led to some important results, a sort of dry residue. I will try to describe below how has it been in my case: what may be estimated as the most important, how I came to this, what was around, etc.

  3. Fuel cell propulsion for urban duty vehicles: Bavarian fuel cell bus project

    International Nuclear Information System (INIS)

    Wurster, R.; Altmann, M.; Sillat, D.; Kalk, K. W.; Hammerschmidt, A.; Stuehler, W.; Holl, E.

    1998-01-01

    Following a feasibility study and a detailed specification phase, the realization of a fuel cell city bus prototype was started in autumn 1996. The project is a joint development effort of Siemens, MAN and Linde, which receives a 50 % funding by the Bavarian State Ministry for Economic Affairs, Transport and Technology (BStMWVT) in the context of the Hydrogen Initiative Bavaria. An MAN low-floor bus will be equipped with the components for a fuel cell drive system. The PEM fuel cell is developed by the power generation division of Siemens. Four fuel cell modules deliver a total electrical output of 120 kW to the two electric motors, which are linked by a summation gearbox by the Siemens Transportation Systems Division. MAN Technologie AG is responsible for the compressed hydrogen storage system allowing for a driving range of more than 250 km, while Linde AG takes care of the hydrogen periphery and delivers the hydrogen for the test operation scheduled for the beginning of the year 2000. Project coordination is done by Ludwig-Boelkow System-technik GmbH. The project is divided into four phases. The conceptual design phase is scheduled to last until the end of 1997. The partly overlapping system integration phase will end in the first quarter of 1999. The subsequent test and commissioning phase will prepare the test operation at the beginning of 2000 with a bus operator yet to be defined. (author)

  4. Design and Manufacture of the Superconducting Bus-bars for the LHC Main Magnets

    CERN Document Server

    Belova, L M; Perinet-Marquet, J L; Ivanov, P; Urpin, C

    2002-01-01

    The main magnets of the LHC are series-connected electrically in different powering circuits by means of superconducting bus-bars, carrying a maximum current of 13 kA. These superconducting bus-bars consist of a superconducting cable thermally and electrically coupled to a copper profile all along the length. The function of the copper profile is essentially to provide an alternative path for the current in case the superconducting cable loses its superconducting state and returns to normal state because of a transient disturbance or of a normal zone propagation coming from the neighbouring magnets. When a superconducting bus-bar quenches to normal state its temperature must always stay below a safe values of about 100°C while the copper is conducting. When a resistive transition is detected, the protection systems triggers the ramping down of the current from 13000 A to 0. The ramp rate must not exceed a maximum value to avoid the transition of magnets series-connected in the circuit. This paper concerns th...

  5. Energy management strategy based on fuzzy logic for a fuel cell hybrid bus

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Dawei; Jin, Zhenhua; Lu, Qingchun [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China)

    2008-10-15

    Fuel cell vehicles, as a substitute for internal-combustion-engine vehicles, have become a research hotspot for most automobile manufacturers all over the world. Fuel cell systems have disadvantages, such as high cost, slow response and no regenerative energy recovery during braking; hybridization can be a solution to these drawbacks. This paper presents a fuel cell hybrid bus which is equipped with a fuel cell system and two energy storage devices, i.e., a battery and an ultracapacitor. An energy management strategy based on fuzzy logic, which is employed to control the power flow of the vehicular power train, is described. This strategy is capable of determining the desired output power of the fuel cell system, battery and ultracapacitor according to the propulsion power and recuperated braking power. Some tests to verify the strategy were developed, and the results of the tests show the effectiveness of the proposed energy management strategy and the good performance of the fuel cell hybrid bus. (author)

  6. Spacecraft computer technology at Southwest Research Institute

    Science.gov (United States)

    Shirley, D. J.

    1993-01-01

    Southwest Research Institute (SwRI) has developed and delivered spacecraft computers for a number of different near-Earth-orbit spacecraft including shuttle experiments and SDIO free-flyer experiments. We describe the evolution of the basic SwRI spacecraft computer design from those weighing in at 20 to 25 lb and using 20 to 30 W to newer models weighing less than 5 lb and using only about 5 W, yet delivering twice the processing throughput. Because of their reduced size, weight, and power, these newer designs are especially applicable to planetary instrument requirements. The basis of our design evolution has been the availability of more powerful processor chip sets and the development of higher density packaging technology, coupled with more aggressive design strategies in incorporating high-density FPGA technology and use of high-density memory chips. In addition to reductions in size, weight, and power, the newer designs also address the necessity of survival in the harsh radiation environment of space. Spurred by participation in such programs as MSTI, LACE, RME, Delta 181, Delta Star, and RADARSAT, our designs have evolved in response to program demands to be small, low-powered units, radiation tolerant enough to be suitable for both Earth-orbit microsats and for planetary instruments. Present designs already include MIL-STD-1750 and Multi-Chip Module (MCM) technology with near-term plans to include RISC processors and higher-density MCM's. Long term plans include development of whole-core processors on one or two MCM's.

  7. Green Applications for Space Power

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft propulsion and power for many decades has relied on Hydrazine monopropellant technology for auxiliary power units (APU), orbital circularization, orbit...

  8. Optimization Model for Headway of a Suburban Bus Route

    Directory of Open Access Journals (Sweden)

    Xiaohong Jiang

    2014-01-01

    Full Text Available Due to relatively low passenger demand, headways of suburban bus route are usually longer than those of urban bus route. Actually it is also difficult to balance the benefits between passengers and operators, subject to the service standards from the government. Hence the headway of a suburban bus route is usually determined on the empirical experience of transport planners. To cope with this problem, this paper proposes an optimization model for designing the headways of suburban bus routes by minimizing the operating and user costs. The user costs take into account both the waiting time cost and the crowding cost. The feasibility and validity of the proposed model are shown by applying it to the Route 206 in Jiangning district, Nanjing city of China. Weightages of passengers’ cost and operating cost are further discussed, considering different passenger flows. It is found that the headway and objective function are affected by the weightages largely.

  9. Global Optimization for Bus Line Timetable Setting Problem

    Directory of Open Access Journals (Sweden)

    Qun Chen

    2014-01-01

    Full Text Available This paper defines bus timetables setting problem during each time period divided in terms of passenger flow intensity; it is supposed that passengers evenly arrive and bus runs are set evenly; the problem is to determine bus runs assignment in each time period to minimize the total waiting time of passengers on platforms if the number of the total runs is known. For such a multistage decision problem, this paper designed a dynamic programming algorithm to solve it. Global optimization procedures using dynamic programming are developed. A numerical example about bus runs assignment optimization of a single line is given to demonstrate the efficiency of the proposed methodology, showing that optimizing buses’ departure time using dynamic programming can save computational time and find the global optimal solution.

  10. Large truck and bus crash facts, 2008. 

    Science.gov (United States)

    2010-03-01

    This annual edition of Large Truck and Bus Crash Facts contains descriptive statistics about fatal, injury, and : property damage only crashes involving large trucks and buses in 2008. Selected crash statistics on passenger : vehicles are also presen...

  11. CFD Investigation on Long-Haul Passenger Bus

    Science.gov (United States)

    Tan, C. F.; Tee, B. T.; Law, H. C.; Lim, T. L.

    2015-09-01

    Air flow distribution is one of the important factors that will influence the bus passenger comfort during long haul travel. Poor air flow distribution not only cause discomfort to the bus passenger but also influence their travel mode as well. The main purpose of this study is to investigate the air flow performance of the bus air-conditioning system through CFD simulation approach. A 3D CAD model of air ducts was drawn and hence analysed by using CFD software, namely ANSYS Fluent, to determine the airflow rate for every outlets of the air-conditioning system. The simulated result was then validated with experimental data obtained from prototype model of air duct. Based on the findings, new design concepts is proposed with the aim to meet the industry requirement as well as to improve the bus passenger comfort during long haul travel.

  12. Transit bus applications of lithium ion batteries : progress and prospects

    Science.gov (United States)

    2012-12-31

    This report provides an overview of diverse transit bus applications of advanced Lithium Ion Batteries (LIBs). The report highlights and illustrates several FTA programs that fostered the successful development, demonstration, and deployment of fuel-...

  13. Analysis of movable bus stop boarding and alighting areas.

    Science.gov (United States)

    2013-05-01

    This study explored the feasibility of using movable and reusable boarding and alighting (B&A) pads at bus stops. : Potential design alternatives in terms of materials and structural support for these pads were evaluated. The review : focused on the ...

  14. How to Reduce Those Costly School Bus Accidents.

    Science.gov (United States)

    Farmer, Ernest

    1985-01-01

    The deterrent to school bus accidents is preparedness. Training programs for drivers and mechanics, equipment specifications, and a community support base are some of the ways to prevent tragedy. (MLF)

  15. Southwest Direct Express Bus Demonstration in Orlando, FL

    Science.gov (United States)

    1988-04-01

    In August 1983, the Orange-Seminole-Osceola Transit Authority (OSOTA) initiated six express bus routes in the southwest corridor of Orlando (known collectively as the Southwest Direct) as an UMTA-funded demonstration project. While one objective of t...

  16. Black silicon solar cells with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....

  17. Understanding Factors of Distraction among Intrastate Bus Driver

    Directory of Open Access Journals (Sweden)

    Yunos Muhammad Nur Annuar Mohd

    2017-01-01

    Full Text Available The increase in number of the world population have affected the demand for public transport especially in larger cities. Intrastate buses are chosen as the main public transport by many people due to its affordable fares. Therefore, a better performance of the intrastate bus drivers would be significant to cater the high demand. Nevertheless, distraction among the intrastate bus drivers have been found as one of the major factors that could affect the performance of the drivers. Therefore, the objective of this paper is to provide a better understanding on the factors of distraction among intrastate bus drivers. This paper refers to findings from previous researches which are related to this field of study. In conclusion, this paper will provide a list of factors of distraction among the intrastate bus drivers which may degrade their performance.

  18. FTA fuel cell bus program : research accomplishments through 2011.

    Science.gov (United States)

    2012-03-01

    Prepared by the Federal Transit Administration (FTA) Office of Research, Demonstration, and Innovation (TRI), this report summarizes the accomplishments of fuel-cell-transit-bus-related research and demonstrations projects supported by FTA through 20...

  19. Modelling Field Bus Communications in Mixed-Signal Embedded Systems

    Directory of Open Access Journals (Sweden)

    Alassir Mohamad

    2008-01-01

    Full Text Available Abstract We present a modelling platform using the SystemC-AMS language to simulate field bus communications for embedded systems. Our platform includes the model of an I/O controller IP (in this specific case an C controller that interfaces a master microprocessor with its peripherals on the field bus. Our platform shows the execution of the embedded software and its analog response on the lines of the bus. Moreover, it also takes into account the influence of the circuits's I/O by including their IBIS models in the SystemC-AMS description, as well as the bus lines imperfections. Finally, we present simulation results to validate our platform and measure the overhead introduced by SystemC-AMS over a pure digital SystemC simulation.

  20. Modelling Field Bus Communications in Mixed-Signal Embedded Systems

    Directory of Open Access Journals (Sweden)

    Patrick Garda

    2008-08-01

    Full Text Available We present a modelling platform using the SystemC-AMS language to simulate field bus communications for embedded systems. Our platform includes the model of an I/O controller IP (in this specific case an I2C controller that interfaces a master microprocessor with its peripherals on the field bus. Our platform shows the execution of the embedded software and its analog response on the lines of the bus. Moreover, it also takes into account the influence of the circuits's I/O by including their IBIS models in the SystemC-AMS description, as well as the bus lines imperfections. Finally, we present simulation results to validate our platform and measure the overhead introduced by SystemC-AMS over a pure digital SystemC simulation.

  1. STRATEGI PENGEMBANGAN TRANSPORTASI WISATA KURA-KURA BUS DI BALI

    Directory of Open Access Journals (Sweden)

    Ayu Kusuma

    2018-01-01

    Full Text Available Kura-Kura Bus is one of tourist transportation companies in Bali with public shuttle bus service in tourism route. Data analysis in this research were using SWOT and AHP analysis, with participants who have position minimal as a supervisor. Participants selected based on their expertise and relevance with this article. Based on the results of SWOT and AHP analysis to develop tourist transportation is Kura-Kura Bus, which is considered the most realistic scenario is an optimistic scenario, with the goal to be a safe and comfortable transportation. To achieve the goal, based on priority strategies that could be done by management of Kura-Kura Bus are developing unique products, finding new markets, favoring public transport services, enchance brand reputation, developing smartphone application, and cross promotion with supplier.

  2. Dynamic Voltage Stability Studies using a Modified IEEE 30-Bus System

    Directory of Open Access Journals (Sweden)

    Oluwafemi Emmanuel Oni

    2016-09-01

    Full Text Available Power System stability is an essential study in the planning and operation of an efficient, economic, reliable and secure electric power system because it encompasses all the facet of power systems operations, from planning, to conceptual design stages of the project as well as during the systems operating life span. This paper presents different scenario of power system stability studies on a modified IEEE 30-bus system which is subjected to different faults conditions. A scenario whereby the longest high voltage alternating current (HVAC line is replaced with a high voltage direct current (HVDC line was implemented. The results obtained show that the HVDC line enhances system stability more compared to the contemporary HVAC line. Dynamic analysis using RMS simulation tool was used on DigSILENT PowerFactory.

  3. DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

    2003-04-01

    The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethylether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operation in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation institute's test track facility near the University Park airport. After modification and optimization of the system on the bus, operation on the campus shuttle route began in early June 2002. However, the

  4. Scenario-based electric bus operation: A case study of Putrajaya, Malaysia

    OpenAIRE

    Lay Eng Teoh; Hooi Ling Khoo; Siew Yoke Goh; Lai Mun Chong

    2018-01-01

    Globally, transportation sector has emerged as one of the major sources of air pollution. Correspondingly, green mobility (with electric bus) is gaining increasing attention as an essential step to mitigate emission concern. As such, a proper electric bus network design and fleet planning is important especially for bus operator to acquire an adequate number of electric bus, right on time, in order to operate electric bus system viably. Thus, this paper aims to examine the possibility to oper...

  5. Regenerative Braking System for Series Hybrid Electric City Bus

    OpenAIRE

    Zhang, Junzhi; Lu, Xin; Xue, Junliang; Li, Bos

    2008-01-01

    Regenerative Braking Systems (RBS) provide an efficient method to assist hybrid electric buses achieve better fuel economy while lowering exhaust emissions. This paper describes the design and testing of three regenerative braking systems, one of which is a series regenerative braking system and two of which are parallel regenerative braking systems. The existing friction based Adjustable Braking System (ABS) on the bus is integrated with each of the new braking systems in order to ensure bus...

  6. VHDL resolved function based inner communication bus for FPGA

    Science.gov (United States)

    Pozniak, Krzysztof T.

    2017-08-01

    This article discusses a method of building an internal, universal and parametric bus. The solution was designed for a variety of FPGA families and popular VHDL compilers. The algorithm of automatic configuration of address space and methods of receiving and sending addressed data are discussed. The basic solution realized in VHDL language in a behavioral form and chosen examples of practical use of the internal bus are presented in detail.

  7. Analysing passenger arrivals rates and waiting time at bus stops

    OpenAIRE

    Kaparias, I.; Rossetti, C.; Trozzi, V.

    2015-01-01

    The present study investigates the rather under-explored topic of passenger waiting times at public transport facilities. Using data collected from part of London’s bus network by means of physical counts, measurements and observations, and complemented by on-site passenger interviews, the waiting behaviour is analysed for a number of bus stops served by different numbers of lines. The analysis employs a wide range of statistical methods and tools, and concentrates on three aspects: passenger...

  8. Spacecraft Charging and the Microwave Anisotropy Probe Spacecraft

    Science.gov (United States)

    Timothy, VanSant J.; Neergaard, Linda F.

    1998-01-01

    The Microwave Anisotropy Probe (MAP), a MIDEX mission built in partnership between Princeton University and the NASA Goddard Space Flight Center (GSFC), will study the cosmic microwave background. It will be inserted into a highly elliptical earth orbit for several weeks and then use a lunar gravity assist to orbit around the second Lagrangian point (L2), 1.5 million kilometers, anti-sunward from the earth. The charging environment for the phasing loops and at L2 was evaluated. There is a limited set of data for L2; the GEOTAIL spacecraft measured relatively low spacecraft potentials (approx. 50 V maximum) near L2. The main area of concern for charging on the MAP spacecraft is the well-established threat posed by the "geosynchronous region" between 6-10 Re. The launch in the autumn of 2000 will coincide with the falling of the solar maximum, a period when the likelihood of a substorm is higher than usual. The likelihood of a substorm at that time has been roughly estimated to be on the order of 20% for a typical MAP mission profile. Because of the possibility of spacecraft charging, a requirement for conductive spacecraft surfaces was established early in the program. Subsequent NASCAP/GEO analyses for the MAP spacecraft demonstrated that a significant portion of the sunlit surface (solar cell cover glass and sunshade) could have nonconductive surfaces without significantly raising differential charging. The need for conductive materials on surfaces continually in eclipse has also been reinforced by NASCAP analyses.

  9. Effect of passenger position on fear of danger experienced during sudden bus stops.

    Science.gov (United States)

    Aoki, Takeo; Uetake, Teruo; Shimoda, Masahiro

    2009-06-01

    The purpose of this study was to identify the effect of bus passengers' positions on their fear of danger when a bus stopped suddenly. A temporary bus running course with one bus stop was set up on the campus of the Tokyo University of Agriculture and Technology (TUAT). The bus ran the course 14 times with the bus stopping twice during the course, once at the bus stop and again just after re-starting from the bus stop. The driver was asked to brake more strongly than usual when stopping. Sixteen students (15 males and 1 female) between the ages of 18 and 21 years participated. In turn, all participants were asked to take 14 different postures in the bus. Participants were also asked to report their level of fear on a rating scale each time the bus stopped. The study showed that (1) passengers' fear of danger at the first sudden stop was typically higher than that at the second stop, (2) standing passengers who held hand straps experienced more fear than those who held fixed safety devices, (3) bus passengers sitting on the centre of the rear seat had a great risk of injury if the bus stopped suddenly, and (4) when passengers faced the window and stood transversely with respect to from the moving direction of the bus and the bus stopped suddenly, passengers' fear of danger was affected by the side of the bus on which they stood as well as which hand they used to grasp a safety device.

  10. CROSS-FRONTIER PUBLIC TRANSPORT: Y BUS

    CERN Multimedia

    CERN Housing Service

    2002-01-01

    'Y' buses cover the journey between Val Thoiry in France (shopping centre including'Migros' and other stores) and Blandonnet in Switzerland, where they stop outside the 'Jumbo' shop, now renamed 'Carrefour'. In France, the buses connect up Thoiry, Sergy and St. Genis, then cross the border to stop outside CERN, Meyrin, before continuing towards Geneva along the 'Route de Meyrin', stopping outside the 'La Tour' hospital, then at the terminus Blandonnet. The normal fare on French territory with a slight incursion into Switzerland for this purpose as far as CERN, Meyrin, is 1.20 Euros per single journey (ticket valid for one hour). The same amount is charged for any single journey in Switzerland. For example, the cost of a single journey between St. Genis and the 'La Tour' hospital would be 2.40 Euros. The season ticket ('Abonnement de Travail') opens the right to purchase a ticket valid over any period of seven days which entitles the holder to as many journeys as required between the bus stop nearest to the pl...

  11. Submarines, spacecraft and exhaled breath.

    Science.gov (United States)

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    extend the underwater endurance to 2-3 weeks. These propulsion engineering changes also reduce periodic ventilation of the submarine's interior and thus put a greater burden on the various maintenance systems. We note that the spaceflight community has similar issues; their energy production mechanisms are essentially air independent in that they rely almost entirely on photovoltaic arrays for electricity generation, with only emergency back-up power from alcohol fuel cells. In response to prolonged underwater submarine AIP operations, months-long spaceflight operations onboard the ISS and planning for future years-long missions to Mars, there has been an increasing awareness that bio-monitoring is an important factor for assessing the health and awareness states of the crewmembers. SAMAP researchers have been proposing various air and bio-monitoring instruments and methods in response to these needs. One of the most promising new methodologies is the non-invasive monitoring of exhaled breath. So, what do the IABR and SAMAP communities have in common? Inhalation toxicology. We are both concerned with contamination from the environment, either as a direct health threat or as a confounder for diagnostic assessments. For example, the exhaled breath from subjects in a contaminated and enclosed artificial environment (submarine or spacecraft) can serve as a model system and a source of contamination for their peers in a cleaner environment. In a similar way, exhaled anaesthetics can serve as a source of contamination in hospital/clinical settings, or exhalation of occupational exposures to tetrachloroethylene can impact family members at home. Instrumentation development. Both communities have similar needs for better, more specific and more sensitive instruments. Certainly, the analytical instruments to be used onboard submarines and spacecraft have severe restrictions on energy use, physical size and ease of operation. The medical and clinical communities have similar long

  12. Passive Plasma Contact Mechanisms for Small-Scale Spacecraft

    Science.gov (United States)

    McTernan, Jesse K.

    Small-scale spacecraft represent a paradigm shift in how entities such as academia, industry, engineering firms, and the scientific community operate in space. However, although the paradigm shift produces unique opportunities to build satellites in unique ways for novel missions, there are also significant challenges that must be addressed. This research addresses two of the challenges associated with small-scale spacecraft: 1) the miniaturization of spacecraft and associated instrumentation and 2) the need to transport charge across the spacecraft-environment boundary. As spacecraft decrease in size, constraints on the size, weight, and power of on-board instrumentation increase--potentially limiting the instrument's functionality or ability to integrate with the spacecraft. These constraints drive research into mechanisms or techniques that use little or no power and efficiently utilize existing resources. One limited resource on small-scale spacecraft is outer surface area, which is often covered with solar panels to meet tight power budgets. This same surface area could also be needed for passive neutralization of spacecraft charging. This research explores the use of a transparent, conductive layer on the solar cell coverglass that is electrically connected to spacecraft ground potential. This dual-purpose material facilitates the use of outer surfaces for both energy harvesting of solar photons as well as passive ion collection. Mission capabilities such as in-situ plasma measurements that were previously infeasible on small-scale platforms become feasible with the use of indium tin oxide-coated solar panel coverglass. We developed test facilities that simulate the space environment in low Earth orbit to test the dual-purpose material and the various application of this approach. Particularly, this research is in support of two upcoming missions: OSIRIS-3U, by Penn State's Student Space Programs Lab, and MiTEE, by the University of Michigan. The purpose of

  13. DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

    2003-04-01

    The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Their strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis (FMEA, referred to by Air Products as a ''HAZOP'' analysis) with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operational in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation Institute's test track facility near the University Park airport. After modification and optimization of the system on

  14. Spacecraft Environmental Interactions Technology, 1983

    Science.gov (United States)

    1985-01-01

    State of the art of environment interactions dealing with low-Earth-orbit plasmas; high-voltage systems; spacecraft charging; materials effects; and direction of future programs are contained in over 50 papers.

  15. Environmental Assessment of Bus Transport in the Trondheim Region - Evaluation of Relevant Bus and Fuel Technologies and their Potential for Mitigating Emissions from Passenger Transportation

    OpenAIRE

    Buø, Tonje

    2015-01-01

    The overall aim of this thesis is to assess the carbon footprint of transport by bus in the Trondheim region. Bus transportation is promoted as a strategy both to combat local pollution problems in urban areas and to mitigate global greenhouse gas emissions from passenger transport. Still, the environmental impacts of bus transport have received fairly limited attention in research. The environmental impacts of bus transport are calculated through life cycle assessment. A model is develo...

  16. Intelligent spacecraft module

    Science.gov (United States)

    Oungrinis, Konstantinos-Alketas; Liapi, Marianthi; Kelesidi, Anna; Gargalis, Leonidas; Telo, Marinela; Ntzoufras, Sotiris; Paschidi, Mariana

    2014-12-01

    The paper presents the development of an on-going research project that focuses on a human-centered design approach to habitable spacecraft modules. It focuses on the technical requirements and proposes approaches on how to achieve a spatial arrangement of the interior that addresses sufficiently the functional, physiological and psychosocial needs of the people living and working in such confined spaces that entail long-term environmental threats to human health and performance. Since the research perspective examines the issue from a qualitative point of view, it is based on establishing specific relationships between the built environment and its users, targeting people's bodily and psychological comfort as a measure toward a successful mission. This research has two basic branches, one examining the context of the system's operation and behavior and the other in the direction of identifying, experimenting and formulating the environment that successfully performs according to the desired context. The latter aspect is researched upon the construction of a scaled-model on which we run series of tests to identify the materiality, the geometry and the electronic infrastructure required. Guided by the principles of sensponsive architecture, the ISM research project explores the application of the necessary spatial arrangement and behavior for a user-centered, functional interior where the appropriate intelligent systems are based upon the existing mechanical and chemical support ones featured on space today, and especially on the ISS. The problem is set according to the characteristics presented at the Mars500 project, regarding the living quarters of six crew-members, along with their hygiene, leisure and eating areas. Transformable design techniques introduce spatial economy, adjustable zoning and increased efficiency within the interior, securing at the same time precise spatial orientation and character at any given time. The sensponsive configuration is

  17. An evaluation of a lane support system for bus rapid transit on narrow shoulders and the relation to bus driver mental workload

    NARCIS (Netherlands)

    Ward, Nicholas J.; Shankwitz, Craig; Gorgestani, Alec; Donath, Max; De Waard, Dick; Boer, Erwin R.

    2006-01-01

    The use of dedicated bus shoulders is a key method for implementing bus rapid transit (BRT) in areas that do not have the space for additional infrastructure. However, the narrow width of the bus shoulder and the need to anticipate traffic hazards in the adjacent lane can both be significant

  18. An Improved Model for Headway-Based Bus Service Unreliability Prevention with Vehicle Load Capacity Constraint at Bus Stops

    Directory of Open Access Journals (Sweden)

    Weiya Chen

    2012-01-01

    Full Text Available This paper presents an improved model for improving headway-based bus route service reliability at bus stops using real-time preventive operation control, taking into account dynamic interaction among random passenger demand, stochastic driving conditions of route segments, and vehicle load capacity constraint. In this model, the real-time information of passenger demand and vehicle operation is involved to predict the imminent unacceptable headway deviation, in the case of which some in-time preventive control strategies are deployed according to the given control rules. As a case study, a single fixed bus route with high-frequency services was simulated and different scenarios of real-time preventive operation control were performed. Headway adherence and average passenger wait time were used to measure bus service reliability. The results show that the improved model is closer to the real bus route service, and using real-time information to predict potential service unreliability and trigger in-time preventive control can reduce bus bunching and avoid big gap.

  19. ANALISIS SARANA ANGKUTAN UMUM BUS DAMRI DI KOTA SEMARANG

    Directory of Open Access Journals (Sweden)

    Subhan Rizal Amin

    2015-12-01

    Full Text Available This study aims to analyze the availability and use of public transportation by taking a case study of the Damri bus which has Ngaliyan-Pucanggading route. The availability of public transport is not comparable to the demand for public transportation services so that the problems of transportation emerge. Additionally, the use of public transport becomes an important factor to develop the transportation. The study is conducted by surveying the Damri passengers of B.04 lane and logistic regression is used for the analysis. The method of determining the needs of transportation is issued by Departemen Perhubungan. It is used to calculate and determine whether the public transportation should be added or reduced. Then, the factors used as the independent variables in the analysis are the Damri’s safety, effectiveness, efficiency, service and reliability. The results show that Perum Damri does not need to add more Damri bus for B.04 because the results’ calculation is 0.6. and the factors that significantly influence the use Damri bus is the variable of safety, effectiveness and efficiency. However, the variables of service and reliability do not significantly influence the use of B.04 Damri bus.Penelitian ini bertujuan untuk menganalisis ketersediaan dan penggunaan angkutan sarana angkutan umum penumpang dengan mengambil studi kasus pada bus Damri jalur dengan trayek Ngaliyan-Pucanggading. Ketersediaan sarana angkutan umum yang tersedia tidak sebanding dengan besarnya permintaan akan jasa angkutan umum oleh masyarakat umum sehingga muncul permasalahan transportasi. Di samping itu, penggunaan angkutan umum yang beroperasi menjadi faktor penting dalam upaya pengembangan sarana transportasi. Penelitian ini dilakukan dengan menggunakan metode survey terhadap para penumpang bus Damri jalur B.04 dan dianalisis dengan Regresi Logistik. Metode penentuan kebutuhan armada dikeluarkan oleh Departemen Perhubungan yang digunakan untuk menghitung apakah suatu

  20. Heat pipe applications for future Air Force spacecraft

    International Nuclear Information System (INIS)

    Mahefkey, T.; Barthelemy, R.R.

    1980-01-01

    This paper summarizes the envisioned, future usage of high and low temperature heat pipes in advanced Air Force spacecraft. Thermal control requirements for a variety of communications, surveillance, and space defense missions are forecast. Thermal design constraints implied by survivability to potential weapons effects are outlined. Applications of heat pipes to meet potential low and high power spacecraft mission requirements and envisioned design constraints are suggested. A brief summary of past Air Force sponsored heat pipe development efforts is presented and directions for future development outlined, including those applicable to advanced photovoltaic and nuclear power subsystem applications of heat pipes

  1. Iterated Local Search Algorithm with Strategic Oscillation for School Bus Routing Problem with Bus Stop Selection

    Directory of Open Access Journals (Sweden)

    Mohammad Saied Fallah Niasar

    2017-02-01

    Full Text Available he school bus routing problem (SBRP represents a variant of the well-known vehicle routing problem. The main goal of this study is to pick up students allocated to some bus stops and generate routes, including the selected stops, in order to carry students to school. In this paper, we have proposed a simple but effective metaheuristic approach that employs two features: first, it utilizes large neighborhood structures for a deeper exploration of the search space; second, the proposed heuristic executes an efficient transition between the feasible and infeasible portions of the search space. Exploration of the infeasible area is controlled by a dynamic penalty function to convert the unfeasible solution into a feasible one. Two metaheuristics, called N-ILS (a variant of the Nearest Neighbourhood with Iterated Local Search algorithm and I-ILS (a variant of Insertion with Iterated Local Search algorithm are proposed to solve SBRP. Our experimental procedure is based on the two data sets. The results show that N-ILS is able to obtain better solutions in shorter computing times. Additionally, N-ILS appears to be very competitive in comparison with the best existing metaheuristics suggested for SBRP

  2. Cost Effectiveness Analysis of Quasi-Static Wireless Power Transfer for Plug-In Hybrid Electric Transit Buses: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lijuan; Gonder, Jeff; Burton, Evan; Brooker, Aaron; Meintz, Andrew; Konan, Arnaud

    2015-11-11

    This study evaluates the costs and benefits associated with the use of a plug-in hybrid electric bus and determines the cost effectiveness relative to a conventional bus and a hybrid electric bus. A sensitivity sweep analysis was performed over a number of a different battery sizes, charging powers, and charging stations. The net present value was calculated for each vehicle design and provided the basis for the design evaluation. In all cases, given present day economic assumptions, the conventional bus achieved the lowest net present value while the optimal plug-in hybrid electric bus scenario reached lower lifetime costs than the hybrid electric bus. The study also performed parameter sensitivity analysis under low market potential assumptions and high market potential assumptions. The net present value of plug-in hybrid electric bus is close to that of conventional bus.

  3. Modeling SMAP Spacecraft Attitude Control Estimation Error Using Signal Generation Model

    Science.gov (United States)

    Rizvi, Farheen

    2016-01-01

    Two ground simulation software are used to model the SMAP spacecraft dynamics. The CAST software uses a higher fidelity model than the ADAMS software. The ADAMS software models the spacecraft plant, controller and actuator models, and assumes a perfect sensor and estimator model. In this simulation study, the spacecraft dynamics results from the ADAMS software are used as CAST software is unavailable. The main source of spacecraft dynamics error in the higher fidelity CAST software is due to the estimation error. A signal generation model is developed to capture the effect of this estimation error in the overall spacecraft dynamics. Then, this signal generation model is included in the ADAMS software spacecraft dynamics estimate such that the results are similar to CAST. This signal generation model has similar characteristics mean, variance and power spectral density as the true CAST estimation error. In this way, ADAMS software can still be used while capturing the higher fidelity spacecraft dynamics modeling from CAST software.

  4. The Glory Program: Global Science from a Unique Spacecraft Integration

    Science.gov (United States)

    Bajpayee Jaya; Durham, Darcie; Ichkawich, Thomas

    2006-01-01

    The Glory program is an Earth and Solar science mission designed to broaden science community knowledge of the environment. The causes and effects of global warming have become a concern in recent years and Glory aims to contribute to the knowledge base of the science community. Glory is designed for two functions: one is solar viewing to monitor the total solar irradiance and the other is observing the Earth s atmosphere for aerosol composition. The former is done with an active cavity radiometer, while the latter is accomplished with an aerosol polarimeter sensor to discern atmospheric particles. The Glory program is managed by NASA Goddard Space Flight Center (GSFC) with Orbital Sciences in Dulles, VA as the prime contractor for the spacecraft bus, mission operations, and ground system. This paper will describe some of the more unique features of the Glory program including the integration and testing of the satellite and instruments as well as the science data processing. The spacecraft integration and test approach requires extensive analysis and additional planning to ensure existing components are successfully functioning with the new Glory components. The science mission data analysis requires development of mission unique processing systems and algorithms. Science data analysis and distribution will utilize our national assets at the Goddard Institute for Space Studies (GISS) and the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP). The Satellite was originally designed and built for the Vegetation Canopy Lidar (VCL) mission, which was terminated in the middle of integration and testing due to payload development issues. The bus was then placed in secure storage in 2001 and removed from an environmentally controlled container in late 2003 to be refurbished to meet the Glory program requirements. Functional testing of all the components was done as a system at the start of the program, very different from a traditional program

  5. Efficient and Robust Data Collection Using Compact Micro Hardware, Distributed Bus Architectures and Optimizing Software

    Science.gov (United States)

    Chau, Savio; Vatan, Farrokh; Randolph, Vincent; Baroth, Edmund C.

    2006-01-01

    Future In-Space propulsion systems for exploration programs will invariably require data collection from a large number of sensors. Consider the sensors needed for monitoring several vehicle systems states of health, including the collection of structural health data, over a large area. This would include the fuel tanks, habitat structure, and science containment of systems required for Lunar, Mars, or deep space exploration. Such a system would consist of several hundred or even thousands of sensors. Conventional avionics system design will require these sensors to be connected to a few Remote Health Units (RHU), which are connected to robust, micro flight computers through a serial bus. This results in a large mass of cabling and unacceptable weight. This paper first gives a survey of several techniques that may reduce the cabling mass for sensors. These techniques can be categorized into four classes: power line communication, serial sensor buses, compound serial buses, and wireless network. The power line communication approach uses the power line to carry both power and data, so that the conventional data lines can be eliminated. The serial sensor bus approach reduces most of the cabling by connecting all the sensors with a single (or redundant) serial bus. Many standard buses for industrial control and sensor buses can support several hundreds of nodes, however, have not been space qualified. Conventional avionics serial buses such as the Mil-Std-1553B bus and IEEE 1394a are space qualified but can support only a limited number of nodes. The third approach is to combine avionics buses to increase their addressability. The reliability, EMI/EMC, and flight qualification issues of wireless networks have to be addressed. Several wireless networks such as the IEEE 802.11 and Ultra Wide Band are surveyed in this paper. The placement of sensors can also affect cable mass. Excessive sensors increase the number of cables unnecessarily. Insufficient number of sensors

  6. Schedule and complex motion of shuttle bus induced by periodic inflow of passengers

    International Nuclear Information System (INIS)

    Nagatani, Takashi; Naito, Yuichi

    2011-01-01

    We have studied the dynamic behavior of a bus in the shuttle bus transportation with a periodic inflow. A bus schedule is closely related to the dynamics. We present the modified circle map model for the dynamics of the shuttle bus. The motion of the shuttle bus depends on the loading parameter and the inflow period. The shuttle bus displays the periodic, quasi-periodic, and chaotic motions with varying both loading parameter and inflow rate. -- Highlights: → We studied the dynamic behavior of a bus in the shuttle bus transportation. → We presented the modified circle map model for the bus schedule. → We clarified the dependence of the tour time on both loading parameter and inflow period.

  7. Improvement of multiprocessing performance by using optical centralized shared bus

    Science.gov (United States)

    Han, Xuliang; Chen, Ray T.

    2004-06-01

    With the ever-increasing need to solve larger and more complex problems, multiprocessing is attracting more and more research efforts. One of the challenges facing the multiprocessor designers is to fulfill in an effective manner the communications among the processes running in parallel on multiple multiprocessors. The conventional electrical backplane bus provides narrow bandwidth as restricted by the physical limitations of electrical interconnects. In the electrical domain, in order to operate at high frequency, the backplane topology has been changed from the simple shared bus to the complicated switched medium. However, the switched medium is an indirect network. It cannot support multicast/broadcast as effectively as the shared bus. Besides the additional latency of going through the intermediate switching nodes, signal routing introduces substantial delay and considerable system complexity. Alternatively, optics has been well known for its interconnect capability. Therefore, it has become imperative to investigate how to improve multiprocessing performance by utilizing optical interconnects. From the implementation standpoint, the existing optical technologies still cannot fulfill the intelligent functions that a switch fabric should provide as effectively as their electronic counterparts. Thus, an innovative optical technology that can provide sufficient bandwidth capacity, while at the same time, retaining the essential merits of the shared bus topology, is highly desirable for the multiprocessing performance improvement. In this paper, the optical centralized shared bus is proposed for use in the multiprocessing systems. This novel optical interconnect architecture not only utilizes the beneficial characteristics of optics, but also retains the desirable properties of the shared bus topology. Meanwhile, from the architecture standpoint, it fits well in the centralized shared-memory multiprocessing scheme. Therefore, a smooth migration with substantial

  8. Scenario-based electric bus operation: A case study of Putrajaya, Malaysia

    Directory of Open Access Journals (Sweden)

    Lay Eng Teoh

    2018-03-01

    Full Text Available Globally, transportation sector has emerged as one of the major sources of air pollution. Correspondingly, green mobility (with electric bus is gaining increasing attention as an essential step to mitigate emission concern. As such, a proper electric bus network design and fleet planning is important especially for bus operator to acquire an adequate number of electric bus, right on time, in order to operate electric bus system viably. Thus, this paper aims to examine the possibility to operate electric bus as a replacement for the conventional bus operation (with natural gas buses for the study area in Putrajaya, Malaysia. In order to determine a proper-designed electric bus operating system in terms of electric bus route, service frequency and quantity, the proposed methodology is developed with the aid of a traffic modeling software to cater various scenarios. Based on the existing (conventional traffic and transit system in Putrajaya, the developed electric bus operating model is calibrated accordingly by considering various operational concerns including battery capacity and charging facility. The resultant findings revealed that the developed electric bus operating system in Putrajaya outperforms the conventional bus operation, not only in generating a higher profit margin for the bus operator, but also satisfying the passengers in a better manner (by carrying more passengers per unit of bus with a lower energy consumption.

  9. Advanced Intelligent System Application to Load Forecasting and Control for Hybrid Electric Bus

    Science.gov (United States)

    Momoh, James; Chattopadhyay, Deb; Elfayoumy, Mahmoud

    1996-01-01

    The primary motivation for this research emanates from providing a decision support system to the electric bus operators in the municipal and urban localities which will guide the operators to maintain an optimal compromise among the noise level, pollution level, fuel usage etc. This study is backed up by our previous studies on study of battery characteristics, permanent magnet DC motor studies and electric traction motor size studies completed in the first year. The operator of the Hybrid Electric Car must determine optimal power management schedule to meet a given load demand for different weather and road conditions. The decision support system for the bus operator comprises three sub-tasks viz. forecast of the electrical load for the route to be traversed divided into specified time periods (few minutes); deriving an optimal 'plan' or 'preschedule' based on the load forecast for the entire time-horizon (i.e., for all time periods) ahead of time; and finally employing corrective control action to monitor and modify the optimal plan in real-time. A fully connected artificial neural network (ANN) model is developed for forecasting the kW requirement for hybrid electric bus based on inputs like climatic conditions, passenger load, road inclination, etc. The ANN model is trained using back-propagation algorithm employing improved optimization techniques like projected Lagrangian technique. The pre-scheduler is based on a Goal-Programming (GP) optimization model with noise, pollution and fuel usage as the three objectives. GP has the capability of analyzing the trade-off among the conflicting objectives and arriving at the optimal activity levels, e.g., throttle settings. The corrective control action or the third sub-task is formulated as an optimal control model with inputs from the real-time data base as well as the GP model to minimize the error (or deviation) from the optimal plan. These three activities linked with the ANN forecaster proving the output to the

  10. An Analysis of 20 Years of Space Weathering Effects on the Boeing 376 Spacecraft

    Science.gov (United States)

    Frith, James; Anz-Meador, Phillip; Cowardin, Heather; Buckalew, Brent; Lederer, Susan

    2015-01-01

    The Boeing HS-376 spin stabilized spacecraft was a popular design that was launched continuously into geosynchronous orbit starting in 1980, with the last launch occurring in 2003. Over 50 of the HS-376 buses were produced to fulfill a variety of different communication missions for countries all over the world. The design of the bus is easily approximated as a telescoping cylinder that is covered with solar cells and an Earth-facing antenna that is despun at the top of the cylinder. The similarity in design and the number of spacecraft launched over a long period of time make the HS-376 a prime target for studying the effects of solar weathering on solar panels as a function of time. A selection of primarily non-operational HS-376 spacecraft launched over a 20-year time period were observed using the United Kingdom Infrared Telescope on Mauna Kea and multi-band, near-infrared photometry produced. Each spacecraft was observed for an entire night cycling through ZYJHK filters and time-varying colors produced to compare near-infrared color as a function of launch date. The resulting analysis shown here may help in the future to set launch date constraints on the parent object of unidentified debris objects or other unknown spacecraft.

  11. A Distributed Control Strategy Based on DC Bus Signaling for Modular Photovoltaic Generation Systems With Battery Energy Storage

    DEFF Research Database (Denmark)

    Sun, Kai; Zhang, Li; Xing, Yan

    2011-01-01

    on improved dc bus signaling is proposed for a modular photovoltaic (PV) generation system with battery energy storage elements. In this paper, the modular PV generation system is composed of three modular dc/dc converters for PV arrays, two grid-connected dc/ac converters, and one dc/dc converter for battery......, grid-connected inversion, and islanding with constant voltage (CV) generation.The power balance of the system under extreme conditions such as the islanding operation with a full-charged battery is taken into account in this control strategy. The dc bus voltage level is employed as an information......Modular generation system, which consists of modular power conditioning converters, is an effective solution to integrate renewable energy sources with conventional utility grid to improve reliability and efficiency, especially for photovoltaic generation. A distributed control strategy based...

  12. Can propulsion and fuel diversity for the bus fleet achieve the win–win strategy of energy conservation and environmental protection?

    International Nuclear Information System (INIS)

    Wang, Renjie; Wu, Ye; Ke, Wenwei; Zhang, Shaojun; Zhou, Boya; Hao, Jiming

    2015-01-01

    Highlights: • We first report WTW energy and environmental impacts of new-energy buses in China. • Both CNGV and BEV eliminate petroleum use but increase the burden of other fossil fuels. • BEV is the best to reduce WTW NO X and VOC emissions but no benefit for PM 2.5 and SO 2 . • CNGV has PM 2.5 emission reductions by 70% greater than DV but no benefit in GHG emissions. • HEV is the only option that can reduce energy use and pollutant emissions at the same time. - Abstract: China is facing serious issues involving energy sufficiency, greenhouse gas (GHG) emissions and air pollution caused partly by the rapid growth of vehicles. In order to relieve those problems, new energy vehicles are introduced into the bus and car market. We adopt life cycle analysis to evaluate the well-to-wheels (WTW) energy consumption, CO 2 emissions and pollutant emissions from the traditional diesel bus and new energy buses, including diesel hybrid electric vehicles (HEVs), compressed natural gas vehicles (CNGVs) and battery electric vehicles (BEVs). This study reports the current situation and projects future scenarios for the BEV bus for several regions in China due to significant regional differences in the power generation mix. Compared to the diesel bus, the HEV bus can reduce petroleum, fossil fuel use and CO 2 emissions by about 20%, and, at the same time, produce stable reduction benefits for all air pollutants. The CNG bus achieves reductions of WTW primary PM 2.5 emissions by 70% over its diesel counterpart and, of course, uses little petroleum; but increases fossil fuel consumption moderately and has no benefit in GHG emissions. The BEV bus can deliver a substantial petroleum consumption advantage and greatly reduce the WTW NO X , VOC and CO emissions; but, if the electricity is generated from burning coal, the BEV bus has no PM 2.5 emission benefit compared to the conventional diesel bus. Currently, the BEV bus increases fossil energy use and CO 2 emissions in the

  13. Ultra-Capacitor Energy Storage in a Large Hybrid Electric Bus

    Science.gov (United States)

    Viterna, L. A.

    1997-01-01

    The power requirements for inner city transit buses are characterized by power peaks about an order of magnitude larger than the average power usage of the vehicle. For these vehicles, hybrid power trains can offer significantly improved fuel economy and exhaust emissions. A critical design challenge, however, has been developing the energy storage and power management system to respond to these rapid power variations. Most hybrid vehicles today use chemical energy storage batteries to supplement the power from the fuel burning generator unit. Chemical storage batteries however, present several difficulties in power management and control. These difficulties include (1) inadequate life, (2) limited current delivery as well as absorption during regenerative braking, (3) inaccurate measurement of state of charge, and (4) stored energy safety issues. Recent advances in ultra-capacitor technology create an opportunity to address these concerns. The NASA Lewis Research Center, in cooperation with industry and academia, has developed an advanced hybrid electric transit bus using ultra-capacitors as the primary energy storage system. At over 15,000-kg gross weight, this is the largest vehicle of its kind ever built using this advanced energy storage technology. Results of analyses show that the vehicle will match the performance of an equivalent conventionally powered vehicle over typical inner city drive cycles. This paper describes the overall power system architecture, the evolution of the control strategy, and analysis of power flow and vehicle performance.

  14. Interfacing the septa movement (DC motor) equipment to the PS control system and the MIL1553 bus

    CERN Document Server

    Dehavay, Claude

    1993-01-01

    Continuing the rejuvenation of the PS Control system , it is planned to replace the Single Transceiver Hybrid used to interface the Septa Movement Equipment by a G64 system connected to the VME crate via the MIL1553 bus. This note explains the G64 hardware interface and details the standard message as defined in the Control Protocole for Power Converter, RF and Stepping Motor equipment.

  15. Mars Comm/Nav MicroSat Network Using the Multi-Mission Bus Launched Piggyback by Ariane 5

    Science.gov (United States)

    Hastrup, R. C.; Cesarone, R. J.; Morabito, D. D.

    1999-01-01

    Recently, NASA's Jet Propulsion Laboratory completed a Mars Exploration Program Architecture Definition Study with strong international participation. The recommendations of this study include establishment of a low cost in-situ communications and navigation satellite network to provide enabling and enhancing support for the international exploration of Mars. This would be the first step toward establishing a "virtual presence throughout the solar system" as called for in NASA's Strategic Plan. Response to the proposed comm/nav satellite network has been very favorably received, as reflected by the inclusion of a line item in NASA's budget submittal to Congress, which provides funding for implementation of the network with first launch in the 2003 opportunity. Funding has already been provided for a phase A study being conducted this year. This paper presents the planned implementation of the comm/nav network, which will utilize microsats based on a multi-mission spacecraft bus being designed for launch by the Ariane 5 as a secondary payload. A companion paper at this conference, entitled "The Multi-Purpose Mars Micro-Mission System Design Utilizing Ariane 5 Piggyback Launch", describes the multimission bus design. This paper addresses the application of the multi-mission bus to the comm/nav microsat mission. Following an introduction, which provides the background that has led to the proposed comm/nav network, the paper discusses the projected user needs with emphasis on the various possible robotic missions (landers, rovers, ascent vehicles, balloons, aircraft, etc.) progressing toward eventual piloted missions. Next, the paper describes the concept for an evolving network of comm/nav microsats and the expected capability to satisfy the user needs. Results of communications and navigation performance analysis are summarized for attractive satellite constellation configurations. The important comm/nav microsat functional requirements on the multi

  16. Potential Influence of Metro on Bus: A Case Study

    Science.gov (United States)

    Selvakumar, M.; Abishek Reddy, M.; Sathish, V.; Venkatesh, R.

    2018-06-01

    A modal shift occurs when one mode of transport has a comparative advantage in a similar market over another. The present work concerns with the development of modal shift model for urban travel in Chennai, India. The modal shift model was calibrated using binary logit technique and validated using hold-out sample method. The validated model was used to predict the probability of shift in selected corridor. The recent introduction of metro rail in Chennai has lead to an increasing competition among public transport modes. To study the influence of metro on bus transport, a Stated Preference (SP) survey was conducted among express bus travellers. Using the SP survey data, a modal shift model was calibrated to estimate the plausible shift from bus to metro. Results indicate that variables like fare- difference, age, and income play an important role in the shift behaviour. When metro fare increases with respect to express bus fare, bus passengers are less willing to use metro and vice-versa.

  17. Bus network redesign for inner southeast suburbs of Melbourne, Australia

    Science.gov (United States)

    Pandangwati, S. T.; Milyanab, N. A.

    2017-06-01

    Public transport is the most effective mode of transport in the era of climate change and oil depletion. It can address climate change issues by reducing urban greenhouse gas emission and oil consumption while at the same time improving mobility. However, many public transport networks are not effective and instead create high operating costs with low frequencies and occupancy. Melbourne is one example of a metropolitan area that faces this problem. Even though the city has well-integrated train and tram networks, Melbourne’s bus network still needs to be improved. This study used network planning approach to redesign the bus network in the City of Glen Eira, a Local Government Area (LGA) in the southeastern part of Metropolitan Melbourne. The study area is the area between Gardenvale North and Oakleigh Station, as well as between Caulfield and Patterson Stations. This area needs network improvement mainly because of the meandering bus routes that run within it. This study aims to provide recommendations for improving the performance of bus services by reducing meandering routes, improving transfer point design and implementing coordinated timetables. The recommendations were formulated based on a ‘ready-made’ concept to increase bus occupancy. This approach can be implemented in other cities with similar problems and characteristics including those in Indonesia.

  18. Potential Influence of Metro on Bus: A Case Study

    Science.gov (United States)

    Selvakumar, M.; Abishek Reddy, M.; Sathish, V.; Venkatesh, R.

    2018-03-01

    A modal shift occurs when one mode of transport has a comparative advantage in a similar market over another. The present work concerns with the development of modal shift model for urban travel in Chennai, India. The modal shift model was calibrated using binary logit technique and validated using hold-out sample method. The validated model was used to predict the probability of shift in selected corridor. The recent introduction of metro rail in Chennai has lead to an increasing competition among public transport modes. To study the influence of metro on bus transport, a Stated Preference (SP) survey was conducted among express bus travellers. Using the SP survey data, a modal shift model was calibrated to estimate the plausible shift from bus to metro. Results indicate that variables like fare-difference, age, and income play an important role in the shift behaviour. When metro fare increases with respect to express bus fare, bus passengers are less willing to use metro and vice-versa.

  19. Artist concept of Galileo spacecraft

    Science.gov (United States)

    1988-01-01

    Galileo spacecraft is illustrated in artist concept. Gallileo, named for the Italian astronomer, physicist and mathematician who is credited with construction of the first complete, practical telescope in 1620, will make detailed studies of Jupiter. A cooperative program with the Federal Republic of Germany the Galileo mission will amplify information acquired by two Voyager spacecraft in their brief flybys. Galileo is a two-element system that includes a Jupiter-orbiting observatory and an entry probe. Jet Propulsion Laboratory (JPL) is Galileo project manager and builder of the main spacecraft. Ames Research Center (ARC) has responsibility for the entry probe, which was built by Hughes Aircraft Company and General Electric. Galileo will be deployed from the payload bay (PLB) of Atlantis, Orbiter Vehicle (OV) 104, during mission STS-34.

  20. Concentrations of polycyclic aromatic hydrocarbons in resuspendable fraction of settled bus dust and its implications for human exposure

    International Nuclear Information System (INIS)

    Gao, Peng; Liu, Sa; Feng, Yujie; Lin, Nan; Lu, Binyu; Zhang, Zhaohan; Cui, Fuyi; Xing, Baoshan; Hammond, S. Katharine

    2015-01-01

    This preliminary study measured Polycyclic Aromatic Hydrocarbons (PAHs) concentrations in the resuspendable fraction of settled dust on 39 bus lines, to evaluate the impact of engine type (gasoline and compressed natural gas) on exposure for commuters and drivers. Benzo(b)fluoranthene(BbF) was the predominant PAH in resuspendable fraction of settled bus dust. The concentration of total PAHs was 92.90 ± 116.00 μg/g (range: 0.57–410) in gasoline buses and 3.97 ± 1.81 (range: 2.01–9.47) in compressed natural gas (CNG) buses. Based on Benzo[a]pyrene (BaP) equivalent concentrations for the sum of 16 PAHs, the average daily dose (ADD) via dust ingestion and dermal contact was calculated. The ADD of PAHs was higher for commuters and drivers in gasoline-powered buses than in buses using CNG buses. For both short and long duration journeys, young commuters were exposed to higher levels of PAHs via dust ingestion and dermal contact than adult commuters. - Highlights: • Resuspendable fraction of settled dust from microenvironment of buses in Harbin monitored for PAHs exposure assessment. • Higher levels of PAHs pollutants at gasoline-powered buses than at compressed natural gas-powered buses. • Non-occupational and occupational exposures in the microenvironment of buses are assessed. - Occupational and non-occupational exposure to PAHs from the microenvironment of bus

  1. Driving a Bus in India: A Study of Indore Bus Rapid Transport System

    Directory of Open Access Journals (Sweden)

    Siddhartha K. RASTOGI

    2017-12-01

    Full Text Available Indore is a typical tier-2 town in the central province of India, fast becoming a regional commercial hub in an economically booming state. The city has a population of over 2 million with no significant public transport. Among the multiple options available, the city started implementing a dedicated corridor based Bus Rapid Transport System (BRTS. The project was jointly mooted by the central, state, and city authorities. However, the system encountered a range of problems, including conflicts and pulls between multiple implementing agencies, delays in delivery of hardware and constructions, land acquisition and compensation, vested interests, public interest litigations, and court orders. The paper analyses the BRTS, introduced in Indore in the midst of 2013, from multiple party perspectives with an underlying search for public policy and public management insights. The broad results indicate feasibility and desirability of the project; however, real problems emerge in public and public perception management.

  2. Training for spacecraft technical analysts

    Science.gov (United States)

    Ayres, Thomas J.; Bryant, Larry

    1989-01-01

    Deep space missions such as Voyager rely upon a large team of expert analysts who monitor activity in the various engineering subsystems of the spacecraft and plan operations. Senior teammembers generally come from the spacecraft designers, and new analysts receive on-the-job training. Neither of these methods will suffice for the creation of a new team in the middle of a mission, which may be the situation during the Magellan mission. New approaches are recommended, including electronic documentation, explicit cognitive modeling, and coached practice with archived data.

  3. Parameters Design for a Parallel Hybrid Electric Bus Using Regenerative Brake Model

    Directory of Open Access Journals (Sweden)

    Zilin Ma

    2014-01-01

    Full Text Available A design methodology which uses the regenerative brake model is introduced to determine the major system parameters of a parallel electric hybrid bus drive train. Hybrid system parameters mainly include the power rating of internal combustion engine (ICE, gear ratios of transmission, power rating, and maximal torque of motor, power, and capacity of battery. The regenerative model is built in the vehicle model to estimate the regenerative energy in the real road conditions. The design target is to ensure that the vehicle meets the specified vehicle performance, such as speed and acceleration, and at the same time, operates the ICE within an expected speed range. Several pairs of parameters are selected from the result analysis, and the fuel saving result in the road test shows that a 25% reduction is achieved in fuel consumption.

  4. Optimal Locations of Bus Stops Connecting Subways near Urban Intersections

    Directory of Open Access Journals (Sweden)

    Yuan Cui

    2015-01-01

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

  5. American Fuel Cell Bus Project Evaluation. Second Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, Leslie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Post, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    This report presents results of the American Fuel Cell Bus (AFCB) Project, a demonstration of fuel cell electric buses operating in the Coachella Valley area of California. The prototype AFCB was developed as part of the Federal Transit Administration's (FTA's) National Fuel Cell Bus Program. Through the non-profit consortia CALSTART, a team led by SunLine Transit Agency and BAE Systems developed a new fuel cell electric bus for demonstration. SunLine added two more AFCBs to its fleet in 2014 and another in 2015. FTA and the AFCB project team are collaborating with the U.S. Department of Energy (DOE) and DOE's National Renewable Energy Laboratory to evaluate the buses in revenue service. This report summarizes the performance results for the buses through June 2015.

  6. Rethinking passive transport: bus fare exemptions and young people's wellbeing.

    Science.gov (United States)

    Jones, Alasdair; Steinbach, Rebecca; Roberts, Helen; Goodman, Anna; Green, Judith

    2012-05-01

    Much recent public health research has emphasised the health impacts for young people of 'active travel' modes, typically defined as walking and cycling. Less research has focused on public transport modes. Drawing on qualitative data, we examine the links between bus travel and wellbeing in London, where young people currently have free bus travel. Our findings indicate that bus travel can be both a physically and socially active experience for young people. We suggest a more nuanced understanding of 'active travel' is now needed, alongside greater attention to urban public transport networks as key sites that impact on important determinants of wellbeing such as independent mobility and social inclusion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. RS-485 Bus Design of a Missile Simulation Training System

    Directory of Open Access Journals (Sweden)

    Liu Fang

    2013-07-01

    Full Text Available In a missile simulation training system with one-master and multi-slaves distributed system structure, a universal controller is necessary due to the system composed with several controllers. In this research, the designed controllers communicate with each other and upper control computer through RS-485 field bus. RS-485 bus including interface circuits, transmission protocol, Cyclic Redundancy Check (CRC method and upper control test software is designed and proposed. The universal controller adopting the designed RS-485 interface circuits is connected through twisted-pair and makes the simulation system, then the controller is tested in line. The results show that the RS-485 bus communicates effectively using the protocol and CRC method, data transmission rates reaches 115.2 kbps, and has a good stability.

  8. DESIGN OF CITY BUS LIFT FOR THE HANDICAPPEDS

    Directory of Open Access Journals (Sweden)

    K. Turgut GÜRSEL

    2003-03-01

    Full Text Available Although the technological developments, the handicappeds do not take part sufficiently in the social and economic life, because buildings, road construction features and means of the transport are not suitable for them. In this study, a lift for handicappeds was designed, that is supposed to be installed to the middle door of city buses. The lift, whose installation should require a few changes at the bus, is driven by a hydraulic system from the street to the level of the bus floor and vice-versa. In the work, at first a construction was developed in accordance with the dimensions of the middle door of a city bus. After determining of dimensions of all elements, a hydraulic mechanism was constructed, that raises the handicapped, its wheelchair and the platform. Furthermore the construction of the elements of the system were determined, and its proofs of strength analysis were indicated

  9. A Shaftless Magnetically Levitated Multifunctional Spacecraft Flywheel Storage System

    Science.gov (United States)

    Stevens, Ken; Thornton, Richard; Clark, Tracy; Beaman, Bob G.; Dennehy, Neil; Day, John H. (Technical Monitor)

    2002-01-01

    Presently many types of spacecraft use a Spacecraft Attitude Control System (ACS) with momentum wheels for steering and electrochemical batteries to provide electrical power for the eclipse period of the spacecraft orbit. Future spacecraft will use Flywheels for combined use in ACS and Energy Storage. This can be done by using multiple wheels and varying the differential speed for ACS and varying the average speed for energy storage and recovery. Technology in these areas has improved since the 1990s so it is now feasible for flywheel systems to emerge from the laboratory for spacecraft use. This paper describes a new flywheel system that can be used for both ACS and energy storage. Some of the possible advantages of a flywheel system are: lower total mass and volume, higher efficiency, less thermal impact, improved satellite integration schedule and complexity, simplified satellite orbital operations, longer life with lower risk, less pointing jitter, and greater capability for high-rate slews. In short, they have the potential to enable new types of missions and provide lower cost. Two basic types of flywheel configurations are the Flywheel Energy Storage System (FESS) and the Integrated Power and Attitude Control System (IPACS).

  10. Time-dependent polar distribution of outgassing from a spacecraft

    Science.gov (United States)

    Scialdone, J. J.

    1974-01-01

    A technique has been developed to obtain a characterization of the self-generated environment of a spacecraft and its variation with time, angular position, and distance. The density, pressure, outgassing flux, total weight loss, and other important parameters were obtained from data provided by two mass measuring crystal microbalances, mounted back to back, at distance of 1 m from the spacecraft equivalent surface. A major outgassing source existed at an angular position of 300 deg to 340 deg, near the rocket motor, while the weakest source was at the antennas. The strongest source appeared to be caused by a material diffusion process which produced a directional density at 1 m distance of about 1.6 x 10 to the 11th power molecules/cu cm after 1 hr in vacuum and decayed to 1.6 x 10 to the 9th power molecules/cu cm after 200 hr. The total average outgassing flux at the same distance and during the same time span changed from 1.2 x 10 to the minus 7th power to 1.4 x to the minus 10th power g/sq cm/s. These values are three times as large at the spacecraft surface. Total weight loss was 537 g after 10 hr and about 833 g after 200 hr. Self-contamination of the spacecraft was equivalent to that in orbit at about 300-km altitude.

  11. Results from active spacecraft potential control on the Geotail spacecraft

    International Nuclear Information System (INIS)

    Schmidt, R.; Arends, H.; Pedersen, A.

    1995-01-01

    A low and actively controlled electrostatic potential on the outer surfaces of a scientific spacecraft is very important for accurate measurements of cold plasma electrons and ions and the DC to low-frequency electric field. The Japanese/NASA Geotail spacecraft carriers as part of its scientific payload a novel ion emitter for active control of the electrostatic potential on the surface of the spacecraft. The aim of the ion emitter is to reduce the positive surface potential which is normally encountered in the outer magnetosphere when the spacecraft is sunlit. Ion emission clamps the surface potential to near the ambient plasma potential. Without emission control, Geotail has encountered plasma conditions in the lobes of the magnetotail which resulted in surface potentials of up to about +70 V. The ion emitter proves to be able to discharge the outer surfaces of the spacecraft and is capable of keeping the surface potential stable at about +2 V. This potential is measured with respect to one of the electric field probes which are current biased and thus kept at a potential slightly above the ambient plasma potential. The instrument uses the liquid metal field ion emission principle to emit indium ions. The ion beam energy is about 6 keV and the typical total emission current amounts to about 15 μA. Neither variations in the ambient plasma conditions nor operation of two electron emitters on Geotail produce significant variations of the controlled surface potential as long as the resulting electron emission currents remain much smaller than the ion emission current. Typical results of the active potential control are shown, demonstrating the surface potential reduction and its stability over time. 25 refs., 5 figs

  12. Spatial analysis of bus transport networks using network theory

    Science.gov (United States)

    Shanmukhappa, Tanuja; Ho, Ivan Wang-Hei; Tse, Chi Kong

    2018-07-01

    In this paper, we analyze the bus transport network (BTN) structure considering the spatial embedding of the network for three cities, namely, Hong Kong (HK), London (LD), and Bengaluru (BL). We propose a novel approach called supernode graph structuring for modeling the bus transport network. A static demand estimation procedure is proposed to assign the node weights by considering the points of interests (POIs) and the population distribution in the city over various localized zones. In addition, the end-to-end delay is proposed as a parameter to measure the topological efficiency of the bus networks instead of the shortest distance measure used in previous works. With the aid of supernode graph representation, important network parameters are analyzed for the directed, weighted and geo-referenced bus transport networks. It is observed that the supernode concept has significant advantage in analyzing the inherent topological behavior. For instance, the scale-free and small-world behavior becomes evident with supernode representation as compared to conventional or regular graph representation for the Hong Kong network. Significant improvement in clustering, reduction in path length, and increase in centrality values are observed in all the three networks with supernode representation. The correlation between topologically central nodes and the geographically central nodes reveals the interesting fact that the proposed static demand estimation method for assigning node weights aids in better identifying the geographically significant nodes in the network. The impact of these geographically significant nodes on the local traffic behavior is demonstrated by simulation using the SUMO (Simulation of Urban Mobility) tool which is also supported by real-world empirical data, and our results indicate that the traffic speed around a particular bus stop can reach a jammed state from a free flow state due to the presence of these geographically important nodes. A comparison

  13. Hydrothermal optimal power flow using continuation method

    International Nuclear Information System (INIS)

    Raoofat, M.; Seifi, H.

    2001-01-01

    The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networks. Its capabilities and promising results are assessed

  14. An Overview of the CNES Propulsion Program for Spacecraft

    Science.gov (United States)

    Cadiou, A.; Darnon, F.; Gibek, I.; Jolivet, L.; Pillet, N.

    2004-10-01

    This paper presents an overview of the CNES spacecraft propulsion activities. The main existing and future projects corresponding to low earth orbit and geostationary platforms are described. These projects cover various types of propulsion subsystems: monopropellant, bipropellant and electric. Monopropellant is mainly used for low earth orbit applications such as earth observation (SPOT/Helios, PLEIADES) or scientific applications (minisatellite PROTEUS line and micro satellites MYRIADE line). Bipropellant is used for geostationary telecommunications satellites (@BUS). The field of application of electric propulsion is the station keeping of geostationary telecommunication satellites (@BUS), main propulsion for specific probes (SMART 1) and fine attitude control for dedicated micro satellites (MICROSCOPE). The preparation of the future and the associated Research and Technology program are also described in the paper. The future developments are mainly dedicated to the performance improvements of electric propulsion which leads to the development of thrusters with higher thrust and higher specific impulse than those existing today, the evaluation of the different low thrust technologies for formation flying applications, the development of new systems to pressurize the propellants (volatile liquid, micro pump), the research on green propellants and different actions concerning components such as over wrapped pressure vessels, valves, micro propulsion. A constant effort is also put on plume effect in chemical and electrical propulsion area (improvement of tools and test activities) in the continuity of the previous work. These different R &T activities are described in detail after a presentation of the different projects and of their propulsion subsystems. The scientific activity supporting the development of Hall thrusters is going on in the frame of the GDR (Groupement de Recherche) CNRS / Universities / CNES / SNECMA on Plasma Propulsion.

  15. Quantum bus of metal nanoring with surface plasmon polaritons

    International Nuclear Information System (INIS)

    Lin Zhirong; Guo Guoping; Tu Tao; Li Haiou; Zou Changling; Ren Xifeng; Guo Guangcan; Chen Junxue; Lu Yonghua

    2010-01-01

    We develop an architecture for distributed quantum computation using quantum bus of plasmonic circuits and spin qubits in self-assembled quantum dots. Deterministic quantum gates between two distant spin qubits can be reached by using an adiabatic approach in which quantum dots couple with highly detuned plasmon modes in a metallic nanoring. Plasmonic quantum bus offers a robust and scalable platform for quantum optics experiments and the development of on-chip quantum networks composed of various quantum nodes, such as quantum dots, molecules, and nanoparticles.

  16. Bus bays inventory using a terrestrial laser scanning system

    Directory of Open Access Journals (Sweden)

    Bobkowska Katarzyna

    2017-01-01

    Full Text Available This article presents the use of laser scanning technology for the assessment of bus bay geo-location. Ground laser scanning is an effective tool for collecting three-dimensional data. Moreover, the analysis of a point cloud dataset can be a source of a lot of information. The authors have outlined an innovative use of data collection and analysis using the TLS regarding information on the flatness of bus bays. The results were finalized in the form of colour three-dimensional maps of deviations and pavement type.

  17. Black silicon with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

  18. Design of temperature monitoring system based on CAN bus

    Science.gov (United States)

    Zhang, Li

    2017-10-01

    The remote temperature monitoring system based on the Controller Area Network (CAN) bus is designed to collect the multi-node remote temperature. By using the STM32F103 as main controller and multiple DS18B20s as temperature sensors, the system achieves a master-slave node data acquisition and transmission based on the CAN bus protocol. And making use of the serial port communication technology to communicate with the host computer, the system achieves the function of remote temperature storage, historical data show and the temperature waveform display.

  19. Empirical investigation of topological and weighted properties of a bus transport network from China

    Science.gov (United States)

    Shu-Min, Feng; Bao-Yu, Hu; Cen, Nie; Xiang-Hao, Shen; Yu-Sheng, Ci

    2016-03-01

    Many bus transport networks (BTNs) have evolved into directed networks. A new representation model for BTNs is proposed, called directed-space P. The bus transport network of Harbin (BTN-H) is described as a directed and weighted complex network by the proposed representation model and by giving each node weights. The topological and weighted properties are revealed in detail. In-degree and out-degree distributions, in-weight and out-weight distributions are presented as an exponential law, respectively. There is a strong relation between in-weight and in-degree (also between out-weight and out-degree), which can be fitted by a power function. Degree-degree and weight-weight correlations are investigated to reveal that BTN-H has a disassortative behavior as the nodes have relatively high degree (or weight). The disparity distributions of out-degree and in-degree follow an approximate power-law. Besides, the node degree shows a near linear increase with the number of routes that connect to the corresponding station. These properties revealed in this paper can help public transport planners to analyze the status quo of the BTN in nature. Project supported by the National High Technology Research and Development Program of China (Grant No. 2014AA110304).

  20. Real-Time-Simulation of IEEE-5-Bus Network on OPAL-RT-OP4510 Simulator

    Science.gov (United States)

    Atul Bhandakkar, Anjali; Mathew, Lini, Dr.

    2018-03-01

    The Real-Time Simulator tools have high computing technologies, improved performance. They are widely used for design and improvement of electrical systems. The advancement of the software tools like MATLAB/SIMULINK with its Real-Time Workshop (RTW) and Real-Time Windows Target (RTWT), real-time simulators are used extensively in many engineering fields, such as industry, education, and research institutions. OPAL-RT-OP4510 is a Real-Time Simulator which is used in both industry and academia. In this paper, the real-time simulation of IEEE-5-Bus network is carried out by means of OPAL-RT-OP4510 with CRO and other hardware. The performance of the network is observed with the introduction of fault at various locations. The waveforms of voltage, current, active and reactive power are observed in the MATLAB simulation environment and on the CRO. Also, Load Flow Analysis (LFA) of IEEE-5-Bus network is computed using MATLAB/Simulink power-gui load flow tool.

  1. The Fermilab Main Injector dipole and quadrupole cooling design and bus connections

    International Nuclear Information System (INIS)

    Satti, J.A.

    1995-06-01

    The proposed system for connecting the low conductivity water (LCW) and the electrical power to the magnets is explained. This system requires minimum maintenance. Stainless steel headers supply LCW to local, secondary manifolds which regulate the flow to the dipole and to the copper bus which conduct both power and cooling water to the quadrupole. A combination of ceramic feedthroughs and thermoplastic hoses insulate the piping electrically from the copper bus system. The utilities for the Main Injector are grouped together at the outside wall of the tunnel leaving most of the enclosure space for servicing. Space above the headers is available for future accelerator expansion. The new dipoles have bolted electrical connections with flexible copper jumpers. Separate compression fittings are used for the water connections. Each dipole magnet has two water circuits in parallel designed to minimize thermal stresses and the number of insulators. Two electrical insulators are used in series because this design has been shown to minimize electrolyses problems and copper ion deposits inside the insulators. The design value of the temperature gradient of the LCW is 8 degrees C

  2. Charging in the environment of large spacecraft

    International Nuclear Information System (INIS)

    Lai, S.T.

    1993-01-01

    This paper discusses some potential problems of spacecraft charging as a result of interactions between a large spacecraft, such as the Space Station, and its environment. Induced electric field, due to VXB effect, may be important for large spacecraft at low earth orbits. Differential charging, due to different properties of surface materials, may be significant when the spacecraft is partly in sunshine and partly in shadow. Triple-root potential jump condition may occur because of differential charging. Sudden onset of severe differential charging may occur when an electron or ion beam is emitted from the spacecraft. The beam may partially return to the ''hot spots'' on the spacecraft. Wake effects, due to blocking of ambient ion trajectories, may result in an undesirable negative potential region in the vicinity of a large spacecraft. Outgassing and exhaust may form a significant spacecraft induced environment; ionization may occur. Spacecraft charging and discharging may affect the electronic components on board

  3. What’s going on at the bus stop? The impact of Auckland’s real time passenger information system on patrons timespace perceptions

    Directory of Open Access Journals (Sweden)

    Phillipa Mitchell

    2016-09-01

    Full Text Available Transport innovations have predominantly been recognised for their power to alter geographic space through time space compression. The emergence of Intelligent Transport Systems provides an interesting new lens through which to investigate individuals’ perceptions and constitution of time and space. This paper focuses on one of these systems, the Real Time Passenger Information Signal Pre-emption System (RTPISP System currently being installed in Auckland, New Zealand. It explores how individuals’ travel experiences are being shaped by interface the RTPISP System provides between the ubiquitous computing background and individuals’ everyday lives. This paper proposes that such technologies are causing more than just the compression of space by time. By embedding the mundane activity of catching the bus in the coded spaces of the RTPISP System new conditions of possibility are emerging allowing these bus patrons to constitute alternative timespaces while waiting for the bus, timespaces which they previously were unable or unwilling to access.

  4. Airborne particulate matter in spacecraft

    Science.gov (United States)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  5. Evaluation of Urban Bus Transport Failure in Gujranwala City of Pakistan

    OpenAIRE

    MUHAMMAD WAQAR ASLAM; ZAHARA BATOOL

    2017-01-01

    This research work has evaluated the performance of urban public bus transport service operating in Gujranwala city of Pakistan. The assessment has been made in terms of financial viability, bus condition, operational performance and user perception. Based on the data requirements, various traffic/transport surveys were conducted including Passenger Boarding and Alighting Survey, Bus Count Survey, Bus Inspection Survey, Illegal Operations Survey and Public Transport User Interview Survey in c...

  6. Kajian Keamanan Pengoperasian Public Transport Tinjauan Terhadap Kekuatan Rangka Body Bus

    OpenAIRE

    Sudiro, B. M

    2010-01-01

    In order to meet the safety and security of the public transportation, design specification of construction body bus or bus frame structures should have an appropriate structural strength and comply with standard design including the safety factor and selection of material besides static and dynamic testing of the part of body bus. It is also realized that a bus carrying passengers have to give secure to the passengers also driver.The fact that a technology concerning with metal works indus...

  7. Developing a viable electric bus service: the Milton Keynes demonstration project

    OpenAIRE

    Miles, John; Potter, Stephen

    2014-01-01

    Buses can be a serious source of city centre air pollution. Electric buses deliver zero emissions but, because of the time required to recharge, more buses are needed for a given timetable than diesel counterparts, so making mainstream electric bus operations prohibitively expensive.\\ud \\ud Early 2014 saw the implementation in Milton Keynes of an electric bus service designed to overcome this problem. An entire bus route has been converted to electric operation with inductive charging at bus ...

  8. Optimal Electrical Energy Slewing for Reaction Wheel Spacecraft

    Science.gov (United States)

    Marsh, Harleigh Christian

    The results contained in this dissertation contribute to a deeper level of understanding to the energy required to slew a spacecraft using reaction wheels. This work addresses the fundamental manner in which spacecrafts are slewed (eigenaxis maneuvering), and demonstrates that this conventional maneuver can be dramatically improved upon in regards to reduction of energy, dissipative losses, as well as peak power. Energy is a fundamental resource that effects every asset, system, and subsystem upon a spacecraft, from the attitude control system which orients the spacecraft, to the communication subsystem to link with ground stations, to the payloads which collect scientific data. For a reaction wheel spacecraft, the attitude control system is a particularly heavy load on the power and energy resources on a spacecraft. The central focus of this dissertation is reducing the burden which the attitude control system places upon the spacecraft in regards to electrical energy, which is shown in this dissertation to be a challenging problem to computationally solve and analyze. Reducing power and energy demands can have a multitude of benefits, spanning from the initial design phase, to in-flight operations, to potentially extending the mission life of the spacecraft. This goal is approached from a practical standpoint apropos to an industry-flight setting. Metrics to measure electrical energy and power are developed which are in-line with the cost associated to operating reaction wheel based attitude control systems. These metrics are incorporated into multiple families of practical high-dimensional constrained nonlinear optimal control problems to reduce the electrical energy, as well as the instantaneous power burdens imposed by the attitude control system upon the spacecraft. Minimizing electrical energy is shown to be a problem in L1 optimal control which is nonsmooth in regards to state variables as well as the control. To overcome the challenge of nonsmoothness, a

  9. Trip-oriented stochastic optimal energy management strategy for plug-in hybrid electric bus

    International Nuclear Information System (INIS)

    Du, Yongchang; Zhao, Yue; Wang, Qinpu; Zhang, Yuanbo; Xia, Huaicheng

    2016-01-01

    A trip-oriented stochastic optimal energy management strategy for plug-in hybrid electric bus is presented in this paper, which includes the offline stochastic dynamic programming part and the online implementation part performed by equivalent consumption minimization strategy. In the offline part, historical driving cycles of the fixed route are divided into segments according to the position of bus stops, and then a segment-based stochastic driving condition model based on Markov chain is built. With the segment-based stochastic model obtained, the control set for real-time implemented equivalent consumption minimization strategy can be achieved by solving the offline stochastic dynamic programming problem. Results of stochastic dynamic programming are converted into a 3-dimensional lookup table of parameters for online implemented equivalent consumption minimization strategy. The proposed strategy is verified by both simulation and hardware-in-loop test of real-world driving cycle on an urban bus route. Simulation results show that the proposed method outperforms both the well-tuned equivalent consumption minimization strategy and the rule-based strategy in terms of fuel economy, and even proved to be close to the optimal result obtained by dynamic programming. Furthermore, the practical application potential of the proposed control method was proved by hardware-in-loop test. - Highlights: • A stochastic problem was formed based on a stochastic segment-based driving condition model. • Offline stochastic dynamic programming was employed to solve the stochastic problem. • The instant power split decision was made by the online equivalent consumption minimization strategy. • Good performance in fuel economy of the proposed method was verified by simulation results. • Practical application potential of the proposed method was verified by the hardware-in-loop test results.

  10. Effects of passengers on bus driver celeration behavior and incident prediction.

    Science.gov (United States)

    Af Wåhlberg, A E

    2007-01-01

    Driver celeration (speed change) behavior of bus drivers has previously been found to predict their traffic incident involvement, but it has also been ascertained that the level of celeration is influenced by the number of passengers carried as well as other traffic density variables. This means that the individual level of celeration is not as well estimated as could be the case. Another hypothesized influence of the number of passengers is that of differential quality of measurements, where high passenger density circumstances are supposed to yield better estimates of the individual driver component of celeration behavior. Comparisons were made between different variants of the celeration as predictor of traffic incidents of bus drivers. The number of bus passengers was held constant, and cases identified by their number of passengers per kilometer during measurement were excluded (in 12 samples of repeated measurements). After holding passengers constant, the correlations between celeration behavior and incident record increased very slightly. Also, the selective prediction of incident record of those drivers who had had many passengers when measured increased the correlations even more. The influence of traffic density variables like the number of passengers have little direct influence on the predictive power of celeration behavior, despite the impact upon absolute celeration level. Selective prediction on the other hand increased correlations substantially. This unusual effect was probably due to how the individual propensity for high or low celeration driving was affected by the number of stops made and general traffic density; differences between drivers in this respect were probably enhanced by the denser traffic, thus creating a better estimate of the theoretical celeration behavior parameter C. The new concept of selective prediction was discussed in terms of making estimates of the systematic differences in quality of the individual driver data.

  11. Designing the lithium bromide air conditioning absorption system for a bus

    International Nuclear Information System (INIS)

    Yusoff Ali; Kamaruzzaman Sopian; Hariadi

    2006-01-01

    A system of air-conditioning using Lithium Bromide absorption system is used as an alternative refrigerant that will not pollute the atmosphere. Lithium Bromide is a chemical salt soluble in water. There is a big difference between vapour compression system and LiBr 2 absorption system. The absorption air conditioning system is made of a generator, a condenser, an evaporator and an absorber with necessary pumps and piping. When LiBr 2 solution is heated under low pressure, water will evaporate first, while LiBr 2 will remain in the solution and will become more concentrated. The water is the refrigerant in this system. The generator, where the water is vapourised, is heated using an electric heater or solar energy. The LiBr 2 weak solution under low pressure in the generator is heated and the water evaporate into vapour. The vapour produced is then cooled in the condenser and then expanded into the evaporator. The refrigerant (water) in evaporator change phase from liquid to vapour by absorbing heat from cooling water, which flow in the coil in the evaporator. The chilled water obtained is then pumped into the fan coil, which will be used in conditioning the passenger area of the bus. The water vapour from the evaporator is absorbed into LiBr 2 solution in the absorber, forming a weak solution of LiBr 2 . the weak solution from the absorber is then pumped back to the generator to regenerate. The absorption system does not use compressor, but requires pumps that need lower input power compared to that of a compressor. The system is considered as a new application for the bus. This will have great potential and will be environmentally friendly. The model in this study will be used for calculation of the cooling load for the bus

  12. Radiation shielding calculations for the vista spacecraft

    International Nuclear Information System (INIS)

    Sahin, Suemer; Sahin, Haci Mehmet; Acir, Adem

    2005-01-01

    The VISTA spacecraft design concept has been proposed for manned or heavy cargo deep space missions beyond earth orbit with inertial fusion energy propulsion. Rocket propulsion is provided by fusion power deposited in the inertial confined fuel pellet debris and with the help of a magnetic nozzle. The calculations for the radiation shielding have been revised under the fact that the highest jet efficiency of the vehicle could be attained only if the propelling plasma would have a narrow temperature distribution. The shield mass could be reduced from 600 tons in the original design to 62 tons. Natural and enriched lithium were the principle shielding materials. The allowable nuclear heating in the superconducting magnet coils (up to 5 mW/cm 3 ) is taken as the crucial criterion for dimensioning the radiation shielding structure of the spacecraft. The space craft mass is 6000 tons. Total peak nuclear power density in the coils is calculated as ∼5.0 mW/cm 3 for a fusion power output of 17 500 MW. The peak neutron heating density is ∼2.0 mW/cm 3 , and the peak γ-ray heating density is ∼3.0 mW/cm 3 (on different points) using natural lithium in the shielding. However, the volume averaged heat generation in the coils is much lower, namely 0.21, 0.71 and 0.92 mW/cm 3 for the neutron, γ-ray and total nuclear heating, respectively. The coil heating will be slightly lower if highly enriched 6 Li (90%) is used instead of natural lithium. Peak values are then calculated as 2.05, 2.15 and 4.2 mW/cm 3 for the neutron, γ-ray and total nuclear heating, respectively. The corresponding volume averaged heat generation in the coils became 0.19, 0.58 and 0.77 mW/cm 3

  13. DETERMINATION OF THE DELAY DEPARTURE TIME OF THE BUS FROM STOPPING POINT INTO THE CAR FLOW

    Directory of Open Access Journals (Sweden)

    P. Gorbachov

    2014-10-01

    Full Text Available An analytical model for estimation of the bus departure delax from the bus stopping point after passenger loading is presented. The model allows to take into account the traffic density on a particular road section of the transport network, as well as the bus parameters.

  14. Computer-Based Video Instruction to Teach Students with Intellectual Disabilities to Use Public Bus Transportation

    Science.gov (United States)

    Mechling, Linda; O'Brien, Eileen

    2010-01-01

    This study investigated the effectiveness of computer-based video instruction (CBVI) to teach three young adults with moderate intellectual disabilities to push a "request to stop bus signal" and exit a city bus in response to target landmarks. A multiple probe design across three students and one bus route was used to evaluate effectiveness of…

  15. 49 CFR 383.123 - Requirements for a school bus endorsement.

    Science.gov (United States)

    2010-10-01

    ... devices required for school buses by State or Federal law or regulation. (ii) Emergency exits and... 49 Transportation 5 2010-10-01 2010-10-01 false Requirements for a school bus endorsement. 383.123... Requirements for a school bus endorsement. (a) An applicant for a school bus endorsement must satisfy the...

  16. The Role of the Coroner in School Bus Accident Prevention: Some Recommendations.

    Science.gov (United States)

    Fox, Michael

    1995-01-01

    Following the deaths of two elementary school students in bus-related accidents in 1992, the Coroner of Quebec held extensive hearings investigating school bus safety and accident prevention. A subsequent report addressed responsibilities of government and school board officials to correct deficiencies in school bus services and provided…

  17. School Bus Safety: What Can Our Schools Do to Protect Our Children?

    Science.gov (United States)

    Dargan, Thomas J.; Silverstone, Adam H.

    2014-01-01

    School districts and school bus contractors are entrusted with the most important of all road users--our nation's children. In the wake of recent newsworthy accidents and attention grabbing headlines regarding unfit bus drivers, claims premised upon school bus accidents have become increasingly tangential and, in turn, personal injury attorneys…

  18. Smart Power Supply for Battery-Powered Systems

    Science.gov (United States)

    Krasowski, Michael J.; Greer, Lawrence; Prokop, Norman F.; Flatico, Joseph M.

    2010-01-01

    A power supply for battery-powered systems has been designed with an embedded controller that is capable of monitoring and maintaining batteries, charging hardware, while maintaining output power. The power supply is primarily designed for rovers and other remote science and engineering vehicles, but it can be used in any battery alone, or battery and charging source applications. The supply can function autonomously, or can be connected to a host processor through a serial communications link. It can be programmed a priori or on the fly to return current and voltage readings to a host. It has two output power busses: a constant 24-V direct current nominal bus, and a programmable bus for output from approximately 24 up to approximately 50 V. The programmable bus voltage level, and its output power limit, can be changed on the fly as well. The power supply also offers options to reduce the programmable bus to 24 V when the set power limit is reached, limiting output power in the case of a system fault detected in the system. The smart power supply is based on an embedded 8051-type single-chip microcontroller. This choice was made in that a credible progression to flight (radiation hard, high reliability) can be assumed as many 8051 processors or gate arrays capable of accepting 8051-type core presently exist and will continue to do so for some time. To solve the problem of centralized control, this innovation moves an embedded microcontroller to the power supply and assigns it the task of overseeing the operation and charging of the power supply assets. This embedded processor is connected to the application central processor via a serial data link such that the central processor can request updates of various parameters within the supply, such as battery current, bus voltage, remaining power in battery estimations, etc. This supply has a direct connection to the battery bus for common (quiescent) power application. Because components from multiple vendors may have

  19. Circuit for Communication Over Power Lines

    Science.gov (United States)

    Krasowski, Michael J.; Prokop, Normal F.; Greer, Lawrence C., III; Nappier, Jennifer

    2011-01-01

    Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system.

  20. Old-Fashioned Bus Trips: New Age Professional Development

    Science.gov (United States)

    Feldhues, Katherine; Epley, Hannah K.

    2018-01-01

    Two 4-H Camp-related bus tours offered new nontraditional professional development (PD) experiences that better align Extension's PD opportunities with the organization's experiential education pedagogy. Creating quality PD opportunities for employees is important because such experiences can affect overall work performance, community connections,…

  1. Analyzing injury severity of bus passengers with different movements.

    Science.gov (United States)

    Li, Duo; Zhao, Yifei; Bai, Qiang; Zhou, Bei; Ling, Hongbiao

    2017-07-04

    Though public transport vehicles are rarely involved in mass casualty accidents, when they are, the number of injuries and fatalities is usually high due to the high passenger capacity. Of the few studies that have been conducted on bus safety, the majority focused on vehicle safety features, road environmental factors, as well as driver characteristics. Nevertheless, few studies have attempted to investigate the underlying risk factors related to bus occupants. This article presents an investigation aimed at identifying the risk factors affecting injury severity of bus passengers with different movements. Three different passenger movement types including standing, seated, and boarding/alighting were analyzed individually using classification and regression tree (CART) method based on publicly available accident database of Great Britain. According to the results of exploratory analyses, passenger age and vehicle maneuver are associated with passenger injury severity in all 3 types of accidents. Moreover, the variable "skidding and overturning" is associated with injury severity of seated passengers and driver age is correlated with injury severity of standing and boarding/alighting passengers. The CART method shows its ability to identify and easily explain the complicated patterns affecting passenger injury severity. Several countermeasures to reduce bus passenger injury severity are recommended.

  2. 49 CFR 374.317 - Identification-bus and driver.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Identification-bus and driver. 374.317 Section 374... SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS PASSENGER CARRIER REGULATIONS Adequacy of Intercity Motor Common Carrier Passenger Service § 374.317 Identification...

  3. A Quantitative Economics Of Seasonality In Bus Patronage In Nigeria

    African Journals Online (AJOL)

    Seasonal variation is a well-known phenomenon, in many endeavrous and enterprises. Passenger of patronage of road transportation by bus is generally implicated as exhibiting excessive seasonality. The study thus set out to empirically investigate the myth or reality of the thesis that trip generation and trip attraction can ...

  4. Staying Safe in the Car and on the Bus

    Science.gov (United States)

    ... a booster! Get in the Back Here's another important safety rule: Sit in the back seat. Kids 12 ... or band concerts once in a while, it's important to follow these rules. When you see the bus driving up, everyone waiting should get into a line. ...

  5. Energy efficient motion control of the electric bus on route

    Science.gov (United States)

    Kotiev, G. O.; Butarovich, D. O.; Kositsyn, B. B.

    2018-02-01

    At present, the urgent problem is the reduction of energy costs of urban motor transport. The article proposes a method of solving this problem by developing an energy-efficient law governing the movement of an electric bus along a city route. To solve this problem, an algorithm is developed based on the dynamic programming method. The proposed method allows you to take into account the constraints imposed on the phase coordinates, control action, as well as on the time of the route. In the course of solving the problem, the model of rectilinear motion of an electric bus on a horizontal reference surface is considered, taking into account the assumptions that allow it to be adapted for the implementation of the method. For the formation of a control action in the equations of motion dynamics, an algorithm for changing the traction / braking torque on the wheels of an electric bus is considered, depending on the magnitude of the control parameter and the speed of motion. An optimal phase trajectory was obtained on a selected section of the road for the prototype of an electric bus. The article presents the comparison of simulation results obtained with the optimal energy efficient control law with the results obtained by a test driver. The comparison proved feasibility of the energy efficient control law for the automobile city electric transport.

  6. Economic impacts of bus rapid transit in southeast Michigan.

    Science.gov (United States)

    2015-12-01

    In recent years, Bus Rapid Transit (BRT) has generated great interest across the United States. There are more than 20 BRT : systems in existence, and more are in the planning stage (including in Detroit). Within the next few years, BRT will be plann...

  7. Improving School Bus Safety. Transportation Research Board Special Report 222.

    Science.gov (United States)

    National Academy of Sciences - National Research Council, Washington, DC. Transportation Research Board.

    While school buses transport more passengers per trip, the rate of occupant fatalities per mile driven for school buses is one-quarter that for passenger cars. Nevertheless, the public expects school districts and other school bus operators to take all reasonable precautions to protect children as they travel to and from school. Although a variety…

  8. Implementation of a Walking School Bus: Lessons Learned

    Science.gov (United States)

    Kong, Alberta S.; Sussman, Andrew L.; Negrete, Sylvia; Patterson, Nissa; Mittleman, Rachel; Hough, Richard

    2009-01-01

    Background: Obesity is rapidly becoming the most common chronic medical condition affecting children. To address this crisis, an Albuquerque, New Mexico, elementary school partnered with University of New Mexico researchers and conducted a Walking School Bus (WSB). The purpose of this article is to examine the feasibility of implementing a WSB.…

  9. Optical bus of centralized relay protection and automation system of ...

    African Journals Online (AJOL)

    The article deals with the system of information collection and transfer from a centralized relay protection and automation system for medium voltage electrical units based on a passive optical bus. The issues of electromagnetic compatibility of technical devices are also considered, and the intensity of electromagnetic ...

  10. A Novel Time Synchronization Method for Dynamic Reconfigurable Bus

    Directory of Open Access Journals (Sweden)

    Zhang Weigong

    2016-01-01

    Full Text Available UM-BUS is a novel dynamically reconfigurable high-speed serial bus for embedded systems. It can achieve fault tolerance by detecting the channel status in real time and reconfigure dynamically at run-time. The bus supports direct interconnections between up to eight master nodes and multiple slave nodes. In order to solve the time synchronization problem among master nodes, this paper proposes a novel time synchronization method, which can meet the requirement of time precision in UM-BUS. In this proposed method, time is firstly broadcasted through time broadcast packets. Then, the transmission delay and time deviations via three handshakes during link self-checking and channel detection can be worked out referring to the IEEE 1588 protocol. Thereby, each node calibrates its own time according to the broadcasted time. The proposed method has been proved to meet the requirement of real-time time synchronization. The experimental results show that the synchronous precision can achieve a bias less than 20 ns.

  11. Bussikontsern Go Bus ihaldab Harjumaa turgu / Signe Kalberg

    Index Scriptorium Estoniae

    Kalberg, Signe, 1959-

    2005-01-01

    AS-i Tarbus ja kaheksa bussiettevõtte ühinemisel moodustati AS Go Bus, ettevõte plaanib veel mitme bussifirma liitmist. Atko Grupi juhatuse esimehe Margo Tomingase, AS Sebe nõukogu esimehe Hugo Osula arvamus. Lisa: Konkurentsiamet hoiab silma peal

  12. Spanish version of Bus Drivers' Job Demands Scale (BDJD-24).

    Science.gov (United States)

    Boada-Grau, Joan; Prizmic-Kuzmica, Aldo-Javier; González-Fernández, Marcos-David; Vigil-Colet, Andreu

    2013-01-01

    Karasek and Theorell's Job Demands-Control Model argues that adverse health-related outcomes, both psychological and physiological, arise from a combination of high job demand and a low level of job control. The objective was to adapt Meijman and Kompier's Bus Drivers' Job Demands Scale (BDJD-24), which enables us to assess the job demands of bus drivers, to Spanish. The final version of the Spanish adaptation was applied to a sample made up of 287 bus drivers living in Spain (80.1% men and 19.9% women), whose average age was 40.44 (SD= 11.78). The results yielded a three-factor structure for the scale used: Time Pressure, Safety, and Passengers. These findings confirm that the Spanish version replicates the factor structure of the original English scale. The reliability of the three subscales was acceptable, ranging from .75 to .84. Furthermore, the subscales were also related to different external correlates and to other scales and showed good convergent and criterion validity. The present instrument can be used to evaluate job demands of bus drivers, as its psychometrics are substantially sound.

  13. High-Tech School Bus Teaches Students on the Road

    Science.gov (United States)

    Katims, Lauren

    2011-01-01

    Last year, kindergarten through high school students in the rural Hector, Arkansas, School District barely had the technology resources that keep kids interested in math and science. This year, they potentially have the most advanced resources in the country--before they even step into the classroom. One school bus in Arkansas' Pope County has…

  14. Measuring Bus Drivers' Occupational Stress Under Changing Working Conditions

    NARCIS (Netherlands)

    Hlotova, Y.; Cats, O.; Meijer, S.A.

    2014-01-01

    Stress is an immense problem in modern society; approximately half of all occupational illnesses are directly or indirectly related to stress. The work of a bus driver is typically associated with high stress levels that negatively influence individual well-being as well as workforce management. The

  15. Steering characteristic of an articulated bus under quasi steady maneuvering

    Science.gov (United States)

    Ubaidillah, Setiawan, Budi Agus; Aridharma, Airlangga Putra; Lenggana, Bhre Wangsa; Caesar, Bernardus Placenta Previo

    2018-02-01

    Articulated buses have been being preferred as public transportation modes due to their operational capacity. Therefore, passenger safety must be the priority of this public service vehicle. This research focused on the analytical approach of steering characteristics of an articulated bus when it maneuvered steadily. Such turning condition could be referred as a stability parameter of the bus for preliminary handling assessment. The analytical approach employed kinematics relationship between front and rear bodies as well as steering capabilities. The quasi steady model was developed to determine steering parameters such as turning radius, oversteer, and understeer. The mathematical model was useful for determining both coefficients of understeer and oversteer. The dimension of articulated bus followed a commonly used bus as utilized in Trans Jakarta busses. Based on the simulation, for one minimum center of the body, the turning radius was calculated about 8.8 m and 7.6 m at steady turning speed of 10 km/h. In neutral condition, the minimum road radius should be 6.5 m at 10 km/h and 6.9 m at 40 km/h. For two centers of the body and oversteer condition, the front body has the turning radius of 8.8 m, while, the rear body has the turning radius of 9.8 m at both turning speeds of 40 km/h. The other steering parameters were discussed accordingly.

  16. GeoBus: sharing science research with schools

    Science.gov (United States)

    Roper, Kathryn; Robinson, Ruth; Moorhouse, Ben

    2016-04-01

    GeoBus (www.geobus.org.uk) is an educational outreach project that was developed in 2012 by the Department of Earth and Environmental Sciences at the University of St Andrews, and it is currently sponsored by industry, NERC, The Crown Estate, and the Scottish Government. The aims of GeoBus are to support the teaching of Earth Science in secondary (middle and high) schools by providing teaching support to schools that have little or no experience in teaching this subject. This is, in part, done through the sharing of new science research outcomes and the experiences of young researchers with school pupils to provide a bridge between industry, higher education institutions, research councils and schools. Since its launch, over 40,000 pupils will have been involved in experiential Earth science learning activities in 190 different schools (over 400 separate visits) across the length and breadth of Scotland: many of these schools are in remote and disadvantaged regions. A new GeoBus project is under development within the Department of Earth Sciences at UCL in London. A key aim of GeoBus is to incorporate new research into our workshops with the main challenge being the development of appropriate resources that incorporate the key learning aims and requirements of the science and geography curricula. GeoBus works closely with researchers, teachers and educational practitioners to tailor the research outcomes to the curricula as much as possible. Over the past four years, GeoBus has developed 17 workshops, 5 challenge events and extensive field trips and each of these activities are trialled and evaluated within the university, and adjustments are made before the activities are delivered in schools. Activities are continually reviewed and further developments are made in response to both teacher and pupil feedback. This critical reflection of the project's success and impact is important to insure a positive and significant contribution to the science learning in

  17. Characterisation of an urban bus network for environmental purposes.

    Science.gov (United States)

    André, Michel; Villanova, André

    2004-12-01

    Since pollutant emissions are closely related to the operating conditions of vehicles, their evaluation usually involves studying these operating conditions (through bus instrumentation and monitoring under actual operation), the design of representative driving or engine test cycles and the measurement of pollutant emissions. A preliminary characterisation of the routes on a bus network should make it possible to identify typical routes, the driving conditions and pollutant emissions of which are then studied. Two approaches are envisaged and applied to the Paris area, for which a wealth of information is available, which should be transferable to other bus networks. Both approaches are based on factorial analysis and automatic clustering, to allow optimum description and the identification of a pertinent typology of the bus routes in several classes. The first attempt at characterisation is based on statistics relating to bus operations: route characteristics (length, dedicated bus lanes, number of stops, location of stops: schools, tourist sites, hospitals, railways or underground stations), travel time, commercial speed, annual statistics (number of passengers, number of vehicles per hour, total kilometres), the irregularity of travel (variation of travel times, injuries, congestion.), as well as information on the problems encountered (congestion, distribution of the passenger load, junctions, bends). A second approach is based on the analysis of the "urban context" in which buses are driven. Population, employment, housing, road network, traffic and places that generate or disturb traffic (schools, railway stations, shopping areas, etc.) are calculated for the Ile de France region, by cells of 100 x 100 m, and collected in a geographical information system (GIS). Statistical analyses enable a typology of these urban cells to be established, the main parameters being density, type of housing, road types and traffic levels. The bus routes are then analysed

  18. THE PREVALENCE OF MUSCULOSKELETAL DISORDERS AMONG BUS DRIVERS IN TRICITY

    Directory of Open Access Journals (Sweden)

    Lalit

    2015-10-01

    Full Text Available Background: Musculoskeletal disorders are widespread in many countries around the world. It has been reported that about 58 percent of the world's population over the age of 10 years spent one third of their life span at work. The population at a high risk include nursing facilities, transportation, mining, food processing, leather tanning, heavy and light manufacturing. Transport workers have been found to be at high risk of developing work related musculoskeletal disorders (WRMSDs. There has been literature evidence regarding the prevalence of musculoskeletal disorders in bus drivers of various cities of different countries. But no study has been done so far in Tricity (Chandigarh, Panchkula and Mohali for the same. The purpose of this study is to investigate the prevalence and characteristics of work related musculoskeletal disorders (WRMSDs among bus drivers of Tricity. Methods: 300 bus drivers were included in the study according to the inclusion and exclusion criteria. The standardized Nordic questionnaire for musculoskeletal disorder and a self administered questionnaire were filled by therapist after the personal interview of each driver. Results: Unpaired t test was used to measure the difference in variable of two groups and Karl Pearson’s correlation coefficient was used to determine the correlation between two entities. In the present study, the subjects were in the age group of 25 to 50 years. Out of the total sample of 300 male bus drivers in Tricity, 159 reported that they had WRMSDs. The prevalence of WRMSDs among bus drivers in Tricity was 53%. In present study, the prevalence of low back pain was highest among the bus drivers that are 30.3%, then neck pain 17.3%, knee pain 14.7%, shoulder 6.3%, ankle and feet 5.7%, upper back 4%, hip and thigh 4%, elbow 1.3% and wrist and hand 1.3%. Thus low back pain, neck pain and knee pain are the most prevalent WRMSDs amongst bus drivers. Conclusions: Work-related biomechanical

  19. Quick Spacecraft Thermal Analysis Tool, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — For spacecraft design and development teams concerned with cost and schedule, the Quick Spacecraft Thermal Analysis Tool (QuickSTAT) is an innovative software suite...

  20. Passive radiative cooling of a HTS coil for attitude orbit control in micro-spacecraft

    Science.gov (United States)

    Inamori, Takaya; Ozaki, Naoya; Saisutjarit, Phongsatorn; Ohsaki, Hiroyuki

    2015-02-01

    This paper proposes a novel radiative cooling system for a high temperature superconducting (HTS) coil for an attitude orbit control system in nano- and micro-spacecraft missions. These days, nano-spacecraft (1-10 kg) and micro-spacecraft (10-100 kg) provide space access to a broader range of spacecraft developers and attract interest as space development applications. In planetary and high earth orbits, most previous standard-size spacecraft used thrusters for their attitude and orbit control, which are not available for nano- and micro-spacecraft missions because of the strict power consumption, space, and weight constraints. This paper considers orbit and attitude control methods that use a superconducting coil, which interacts with on-orbit space plasmas and creates a propulsion force. Because these spacecraft cannot use an active cooling system for the superconducting coil because of their mass and power consumption constraints, this paper proposes the utilization of a passive radiative cooling system, in which the superconducting coil is thermally connected to the 3 K cosmic background radiation of deep space, insulated from the heat generation using magnetic holders, and shielded from the sun. With this proposed cooling system, the HTS coil is cooled to 60 K in interplanetary orbits. Because the system does not use refrigerators for its cooling system, the spacecraft can achieve an HTS coil with low power consumption, small mass, and low cost.

  1. Significance of Phébus-FP results for plant safety in Switzerland

    International Nuclear Information System (INIS)

    Birchley, J.; Güntay, S.

    2013-01-01

    Highlights: • Prototypicality of Phebus is unique for severe accident integral code assessment. • MELCOR and SCDAP show good simulation capability. • Phebus revealed knowledge gaps concerning organic iodine source. • Complementary studies seek to reduce uncertainties. • New engineering technology is developed to resolve organic iodine issue. - Abstract: Switzerland, in common with other countries, uses source term estimates to formulate emergency plans in the unlikely event of an accident with release of activity to the environment. In the past estimates have typically been based on conservative treatments of the accident sequence, necessitated by the limited validation status of models used for the phenomena that control the reactor accident evolution. Although analyses using best-estimate tools frequently indicated substantially smaller releases – knowledge and data were insufficient to place reliance on the methods or the calculated results. The Phébus programme is unique in providing a source of integral transient data on fission product release, transport and chemical behaviour under prototypic conditions, capturing the entire portfolio of processes – transport, material and chemical – and their causal interaction. To this day, no other source of such data is available. These data provide a means to assess, improve and validate methods for source term evaluation and establish the needs for establishing new processes to mitigate the source term. There are strong synergies and complementarities between the Phébus project, the International Source Term Project, the iodine-related studies at PSI and the aerosol retention projects at PSI, and current moves toward improved management/mitigation of severe accidents. The Federal Nuclear Safety Inspectorate (ENSI), Paul Scherrer Institute (PSI) and the Swiss utilities running five nuclear power plants share in the findings. The need to strengthen the foundation on which we perform best

  2. School bus pollution and changes in the air quality at schools: a case study.

    Science.gov (United States)

    Li, Chunlei; Nguyen, Quyen; Ryan, Patrick H; Lemasters, Grace K; Spitz, Henry; Lobaugh, Megan; Glover, Samuel; Grinshpun, Sergey A

    2009-05-01

    Millions of children attending US schools are exposed to traffic-related air pollutants, including health-relevant ultrafine aerosols generated from school buses powered with diesel fuel. This case study was established in a midwestern (USA) metropolitan area to determine the concentration and elemental composition of aerosol in the vicinity of a public school during morning hours when the bus traffic in and out of the adjacent depot was especially intense. Simultaneous measurements were performed at a control site. The ambient aerosol was first characterized in real time using a particle size selective aerosol spectrometer and then continuously monitored at each site with a real-time non-size-selective instrument that detected particles of 20 nm to >1 microm. In addition, air samples were collected with PM2.5 Harvard Impactors and analyzed for elemental composition using the X-ray fluorescence technique (for 38 elements) and thermal-optical transmittance (for carbon). The measurements were conducted during two seasons: in March at ambient temperature around 0 degrees C and in May when it ranged mostly between 10 and 20 degrees C. The particle number concentration at the test site exhibited high temporal variability while it was time independent at the control site. Overall, the aerosol particle count at the school was 4.7 +/- 1.0 times (March) and 2.2 +/- 0.4 times (May) greater than at the control site. On some days, a 15 min-averaged particle number concentration showed significant correlation with the number of school bus arrivals and departures during these time intervals. On other days, the correlation was less than statistically significant. The 3 h time-averaged particle concentrations determined in the test site on days when the school buses operated were found to be more than two-fold greater (on average) than those measured on bus-free days at the same location, and this difference was statistically significant. Overall, the data suggest a possible

  3. Laboratory Spacecraft Data Processing and Instrument Autonomy: AOSAT as Testbed

    Science.gov (United States)

    Lightholder, Jack; Asphaug, Erik; Thangavelautham, Jekan

    2015-11-01

    Recent advances in small spacecraft allow for their use as orbiting microgravity laboratories (e.g. Asphaug and Thangavelautham LPSC 2014) that will produce substantial amounts of data. Power, bandwidth and processing constraints impose limitations on the number of operations which can be performed on this data as well as the data volume the spacecraft can downlink. We show that instrument autonomy and machine learning techniques can intelligently conduct data reduction and downlink queueing to meet data storage and downlink limitations. As small spacecraft laboratory capabilities increase, we must find techniques to increase instrument autonomy and spacecraft scientific decision making. The Asteroid Origins Satellite (AOSAT) CubeSat centrifuge will act as a testbed for further proving these techniques. Lightweight algorithms, such as connected components analysis, centroid tracking, K-means clustering, edge detection, convex hull analysis and intelligent cropping routines can be coupled with the tradition packet compression routines to reduce data transfer per image as well as provide a first order filtering of what data is most relevant to downlink. This intelligent queueing provides timelier downlink of scientifically relevant data while reducing the amount of irrelevant downlinked data. Resulting algorithms allow for scientists to throttle the amount of data downlinked based on initial experimental results. The data downlink pipeline, prioritized for scientific relevance based on incorporated scientific objectives, can continue from the spacecraft until the data is no longer fruitful. Coupled with data compression and cropping strategies at the data packet level, bandwidth reductions exceeding 40% can be achieved while still downlinking data deemed to be most relevant in a double blind study between scientist and algorithm. Applications of this technology allow for the incorporation of instrumentation which produces significant data volumes on small spacecraft

  4. Multiple spacecraft Michelson stellar interferometer

    Science.gov (United States)

    Stachnik, R. V.; Arnold, D.; Melroy, P.; Mccormack, E. F.; Gezari, D. Y.

    1984-01-01

    Results of an orbital analysis and performance assessment of SAMSI (Spacecraft Array for Michelson Spatial Interferometry) are presented. The device considered includes two one-meter telescopes in orbits which are identical except for slightly different inclinations; the telescopes achieve separations as large as 10 km and relay starlight to a central station which has a one-meter optical delay line in one interferometer arm. It is shown that a 1000-km altitude, zero mean inclination orbit affords natural scanning of the 10-km baseline with departures from optical pathlength equality which are well within the corrective capacity of the optical delay line. Electric propulsion is completely adequate to provide the required spacecraft motions, principally those needed for repointing. Resolution of 0.00001 arcsec and magnitude limits of 15 to 20 are achievable.

  5. Spacecraft Tests of General Relativity

    Science.gov (United States)

    Anderson, John D.

    1997-01-01

    Current spacecraft tests of general relativity depend on coherent radio tracking referred to atomic frequency standards at the ground stations. This paper addresses the possibility of improved tests using essentially the current system, but with the added possibility of a space-borne atomic clock. Outside of the obvious measurement of the gravitational frequency shift of the spacecraft clock, a successor to the suborbital flight of a Scout D rocket in 1976 (GP-A Project), other metric tests would benefit most directly by a possible improved sensitivity for the reduced coherent data. For purposes of illustration, two possible missions are discussed. The first is a highly eccentric Earth orbiter, and the second a solar-conjunction experiment to measure the Shapiro time delay using coherent Doppler data instead of the conventional ranging modulation.

  6. Attitude Fusion Techniques for Spacecraft

    DEFF Research Database (Denmark)

    Bjarnø, Jonas Bækby

    Spacecraft platform instability constitutes one of the most significant limiting factors in hyperacuity pointing and tracking applications, yet the demand for accurate, timely and reliable attitude information is ever increasing. The PhD research project described within this dissertation has...... served to investigate the solution space for augmenting the DTU μASC stellar reference sensor with a miniature Inertial Reference Unit (IRU), thereby obtaining improved bandwidth, accuracy and overall operational robustness of the fused instrument. Present day attitude determination requirements are met...... of the instrument, and affecting operations during agile and complex spacecraft attitude maneuvers. As such, there exists a theoretical foundation for augmenting the high frequency performance of the μASC instrument, by harnessing the complementary nature of optical stellar reference and inertial sensor technology...

  7. Autonomous spacecraft rendezvous and docking

    Science.gov (United States)

    Tietz, J. C.; Almand, B. J.

    A storyboard display is presented which summarizes work done recently in design and simulation of autonomous video rendezvous and docking systems for spacecraft. This display includes: photographs of the simulation hardware, plots of chase vehicle trajectories from simulations, pictures of the docking aid including image processing interpretations, and drawings of the control system strategy. Viewgraph-style sheets on the display bulletin board summarize the simulation objectives, benefits, special considerations, approach, and results.

  8. Nonlinearity-induced spacecraft tumbling

    International Nuclear Information System (INIS)

    Amos, A.K.

    1994-01-01

    An existing tumbling criterion for the dumbbell satellite in planar librations is reexamined and modified to reflect a recently identified tumbling mode associated with the horizontal attitude orientation. It is shown that for any initial attitude there exists a critical angular rate below which the motion is oscillatory and harmonic and beyond which a continuous tumbling will ensue. If the angular rate is at the critical value the spacecraft drifts towards the horizontal attitude from which a spontaneous periodic tumbling occurs

  9. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  10. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: First Results Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2011-03-01

    This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. This report provides the early data results and implementation experience of the AT fuel cell bus since it was placed in service.

  11. Understanding and Mitigating the Charging Behavior of Next Generation Complex and Active Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft that are fundamentally more complex and higher powered are necessary to expand our scientific missions and take commercial space endeavors to the next...

  12. Worldwide Spacecraft Crew Hatch History

    Science.gov (United States)

    Johnson, Gary

    2009-01-01

    The JSC Flight Safety Office has developed this compilation of historical information on spacecraft crew hatches to assist the Safety Tech Authority in the evaluation and analysis of worldwide spacecraft crew hatch design and performance. The document is prepared by SAIC s Gary Johnson, former NASA JSC S&MA Associate Director for Technical. Mr. Johnson s previous experience brings expert knowledge to assess the relevancy of data presented. He has experience with six (6) of the NASA spacecraft programs that are covered in this document: Apollo; Skylab; Apollo Soyuz Test Project (ASTP), Space Shuttle, ISS and the Shuttle/Mir Program. Mr. Johnson is also intimately familiar with the JSC Design and Procedures Standard, JPR 8080.5, having been one of its original developers. The observations and findings are presented first by country and organized within each country section by program in chronological order of emergence. A host of reference sources used to augment the personal observations and comments of the author are named within the text and/or listed in the reference section of this document. Careful attention to the selection and inclusion of photos, drawings and diagrams is used to give visual association and clarity to the topic areas examined.

  13. Integrating standard operating procedures with spacecraft automation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft automation has the potential to assist crew members and spacecraft operators in managing spacecraft systems during extended space missions. Automation can...

  14. Problems with the implementation of bus transport contracting in South Africa

    Directory of Open Access Journals (Sweden)

    Jackie Walters

    2012-11-01

    Full Text Available South Africa has had a policy of competitive tendering for the provision of public transport services (subsidised commuter bus services since the mid-1980s. Although this policy approach was conceptualised by the previous government, prior to the transfer of political power in 1994, it was reaffirmed in a 1996 White Paper on National Transport Policy. Despite the nearly 25 years that have passed since the intention to tender services, only about 32% of the subsidy budget is currently spent on some form of contracting. The majority of services are still operated on authorisations (interim contracts which formalised services that operators were operating pre-1994. The purpose of this paper is to analyse the reasons why public transport contracting policy progress has been so slow in South Africa. The paper relies on an extensive study that was conducted regarding policy implementation obstacles in general, as well as a questionnaire survey among the subsidised commuter bus operators to solicit their views on the reasons for the delay in the implementation of the contracting system in the country. The findings of the survey indicate that the major issues hindering the implementation of the contracting system are to be found in a lack of funding, lack of capacity to implement policy and major operational issues in the permit offices.

  15. 10 CFR 830 Major Modification Determination for the ATR Diesel Bus (E-3) and Switchgear Replacement

    International Nuclear Information System (INIS)

    Duckwitz, Noel

    2011-01-01

    Near term replacement of aging and obsolescent original ATR equipment has become important to ensure ATR capability in support of NE's long term national missions. To that end, a mission needs statement has been prepared for a non-major system acquisition which is comprised of three interdependent subprojects. The first project, subject of this determination, will replace the existent diesel-electrical bus (E-3) and associated switchgear. More specifically, INL proposes transitioning ATR to 100% commercial power with appropriate emergency backup to include: (1) Provide commercial power as the normal source of power to the ATR loads currently supplied by diesel-electric power. (2) Provide backup power to the critical ATR loads in the event of a loss of commercial power. (3) Replace obsolescent critical ATR power distribution equipment, e.g., switchgear, transformers, motor control centers, distribution panels. Completion of this and two other age-related projects (primary coolant pump and motor replacement and emergency firewater injection system replacement) will resolve major age related operational issues plus make a significant contribution in sustaining the ATR safety and reliability profile. The major modification criteria evaluation of the project pre-conceptual design identified several issues make the project a major modification: (1) Evaluation Criteria No.2 (Footprint change). The addition of a new PC-4 structure to the ATR Facility to house safety-related SSCs requires careful attention to maintaining adherence to applicable engineering and nuclear safety design criteria (e.g., structural qualification, fire suppression) to ensure no adverse impacts to the safety-related functions of the housed equipment. (2) Evaluation Criteria No.3 (Change of existing process). The change to the strategy for providing continuous reliable power to the safety-related emergency coolant pumps requires careful attention and analysis to ensure it meets a project primary

  16. Rancang Bangun Sistem Pemesanan Tiket Bus Kupang-Atambua Berbasis SMS Gateway

    Directory of Open Access Journals (Sweden)

    Emerensiana Ngaga

    2016-11-01

    Full Text Available Bus merupakan alat transportasi yang paling banyak digunakan masyarakat karena harga yang murah dan masih terjangkau untuk masyarakat kalangan ekonomi menengah ke bawah.  Umumnya pemesanan tiket bus dilakukan dengan mendatangi langsung tempat penjualan tiket bus atau dengan cara menelepon ke kantor agen. Proses pemesanan seperti ini  memiliki kekurangan dimana pegawai kerepotan dalam mencatat dan seringkali terjadi kesalahan dalam mencatat pemesanan tiket. Sedangkan untuk waktu pemesanan, umumnya calon penumpang melakukan pemesanan tiket, satu atau dua hari sebelum keberangkatan dan ada juga yang tidak sempat memesan tiket beberapa hari sebelumnya dan melakukan pembelian tiket pada hari keberangkatan sehingga sering kali tidak mendapatkan tiket. Penelitian ini bertujuan merancang bangun sistem pemesanan tiket bus berbasis SMS Gateway yang memberikan kemudahan layanan pemesanan tiket bus bagi masyarakat secara jarak jauh serta kemudahan mengetahui informasi penjadwalan bus dengan cepat. Aplikasi dibangun menggunakan metode Unified Process, dengan bahasa pemrograman Java NetBeansIDE 7.3.1, MySQL sebagai database dan Gammu sebagai software untuk membantu pembangunan aplikasi SMS Gateway. Hasil dari penelitian ini adalah sebuah sistem pemesanan tiket bus yang memberikan alternatif baru proses pemesanan tiket bus secara baik tanpa ada permasalahan jarak dan waktu. Selain itu masyarakat juga dapat mengetahui informasi jadwal bus, harga tiket dan juga informasi bila terjadi perubahan jadwal keberangkatan bus.   Kata kunci— Bus, Tiket, SMS Gateway, Unified Process

  17. A train for the bus(bars)

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    On 8 April, the first SMACC (Superconducting Magnets and Circuits Consolidation) teams began work in the LHC tunnel. They are responsible for opening the interconnects between the magnets, laying the groundwork for the series of operations that will be performed by the team riding the ‘consolidation train’.   A technician installs the machine tool that allows them to prepare the surface of the section of the bar where the shunt will be fixed. The LHC’s 1,670 dipoles and quadrupoles are powered by power converters and connected by copper 'busbars’. The superconducting cables run through these bars, carrying a current of up to 11,850 amps. Six superconducting cables meet at each interconnect, where they are held together by a soldered (see box) electrical connection sandwiched between two pieces of copper, forming the splice between the busbars of the neighbouring magnets. The integrity of the electrical circuit is depen...

  18. Application Note: Power Grid Modeling With Xyce.

    Energy Technology Data Exchange (ETDEWEB)

    Sholander, Peter E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    This application note describes how to model steady-state power flows and transient events in electric power grids with the SPICE-compatible Xyce TM Parallel Electronic Simulator developed at Sandia National Labs. This application notes provides a brief tutorial on the basic devices (branches, bus shunts, transformers and generators) found in power grids. The focus is on the features supported and assumptions made by the Xyce models for power grid elements. It then provides a detailed explanation, including working Xyce netlists, for simulating some simple power grid examples such as the IEEE 14-bus test case.

  19. Determination of the Optimum Heat Transfer Coefficient and Temperature Rise Analysis for a Lithium-Ion Battery under the Conditions of Harbin City Bus Driving Cycles

    Directory of Open Access Journals (Sweden)

    Xiaogang Wu

    2017-10-01

    Full Text Available This study investigated the heat problems that occur during the operation of power batteries, especially thermal runaway, which usually take place in high temperature environments. The study was conducted on a ternary polymer lithium-ion battery. In addition, a lumped parameter thermal model was established to analyze the thermal behavior of the electric bus battery system under the operation conditions of the driving cycles of the Harbin city electric buses. Moreover, the quantitative relationship between the optimum heat transfer coefficient of the battery and the ambient temperature was investigated. The relationship between the temperature rise (Tr, the number of cycles (c, and the heat transfer coefficient (h under three Harbin bus cycles have been investigated at 30 °C, because it can provide a basis for the design of the battery thermal management system. The results indicated that the heat transfer coefficient that meets the requirements of the battery thermal management system is the cubic power function of the ambient temperature. Therefore, if the ambient temperature is 30 °C, the heat transfer coefficient should be at least 12 W/m2K in the regular bus lines, 22 W/m2K in the bus rapid transit lines, and 32 W/m2K in the suburban lines.

  20. Spacecraft Jitter Attenuation Using Embedded Piezoelectric Actuators

    Science.gov (United States)

    Belvin, W. Keith

    1995-01-01

    Remote sensing from spacecraft requires precise pointing of measurement devices in order to achieve adequate spatial resolution. Unfortunately, various spacecraft disturbances induce vibrational jitter in the remote sensing instruments. The NASA Langley Research Center has performed analysis, simulations, and ground tests to identify the more promising technologies for minimizing spacecraft pointing jitter. These studies have shown that the use of smart materials to reduce spacecraft jitter is an excellent match between a maturing technology and an operational need. This paper describes the use of embedding piezoelectric actuators for vibration control and payload isolation. In addition, recent advances in modeling, simulation, and testing of spacecraft pointing jitter are discussed.