Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Engineers

  • chemical engineer
  • design engineer
  • ecosystem engineer
  • plastic engineer
  • structural engineer
  • system engineer

  • Selected Abstracts


    ABSTRACT,:,This note illustrates the potential impact of the specification of a convex production technology on establishing minimal costs compared to the use of a non-convex technology when benchmarking electricity distributors. This methodological reflection is mainly motivated by recent engineering literature providing evidence for non-convexities in electricity distribution. An empirical illustration using non-parametric specifications of technology illustrates this main point using a sample of Spanish electricity distribution firms earlier analysed in Grifell-Tatjé and Lovell (2003). [source]

    The Economist as Engineer: Game Theory, Experimentation, and Computation as Tools for Design Economics

    ECONOMETRICA, Issue 4 2002
    Alvin E. Roth
    Economists have lately been called upon not only to analyze markets, but to design them. Market design involves a responsibility for detail, a need to deal with all of a market's complications, not just its principle features. Designers therefore cannot work only with the simple conceptual models used for theoretical insights into the general working of markets. Instead, market design calls for an engineering approach. Drawing primarily on the design of the entry level labor market for American doctors (the National Resident Matching Program), and of the auctions of radio spectrum conducted by the Federal Communications Commission, this paper makes the case that experimental and computational economics are natural complements to game theory in the work of design. The paper also argues that some of the challenges facing both markets involve dealing with related kinds of complementarities, and that this suggests an agenda for future theoretical research. [source]

    Recollections of an Inquiring Engineer

    GROUND WATER, Issue 5 2009
    Ken Rushton
    First page of article [source]

    Dr Olivier Coussy, Scientist and Engineer of the Mechanics and Physics of Porous Materials (1953,2010)

    Franz-Josef Ulm
    No abstract is available for this article. [source]

    Notes from Toyota-land: An American Engineer in Japan.

    By Darius Mehri
    No abstract is available for this article. [source]

    Domenico Fontana (1543,1607) und seine Sippe , Berühmte Tessiner Ingenieurarchitekten in Diensten von Papst und König

    BAUTECHNIK, Issue 3 2007
    Paul Caminada Dipl.-Ing.
    Vor 400 Jahren, anno 1607, starb "ingegniere maggiore del Regno" (Oberingenieur des Königreichs) Domenico Fontana in Neapel und wurde dort in der Kirche S. Anna dei Lombardi feierlich beigesetzt. Er wurde 1543 in Melide am Luganer See geboren als Sohn des Sebastiano Fontana und dessen Frau Domenica, geborene Paerino. Die Fontana , Domenico mit den Brüdern Giovanni und Marsilio sowie der Neffe Carlo Maderno, geboren in Capologo am unteren Luganer See , hatten sich in jungen Jahren aufgemacht, um ihr Glück in Rom zu suchen. Die fremde Herkunft der Tessiner Comasken oder "comacini" (maestri), die aus dem damaligen Gebiet der Diözese Como stammten, war kennzeichnend für das Architekturambiente von imposanten Kirchen, Palästen und Residenzen in der zweiten Hälfte des 16. und Anfang des 17. Jahrhunderts, das von Nicht-Römern dominiert wurde. In der Fremde hatten sie es , zusammen mit vielen anderen, darunter auch Francesco Borromini, ein Schüler und Mitarbeiter von Domenico s Neffen Carlo Maderno , zu Erfolg, Ruhm und großem Ansehen gebracht. Die Berufsausbildung der Tessiner Immigranten war ursprünglich in der Hauptsache eine handwerkliche (Stukkateure, Steinmetze und Maurer), wobei die Fähigsten zu Meistern, Architekten und Ingenieuren aufstiegen. Durch ständige Weiterbildung wußten die Fontana mit Zirkel, Winkel und Meßlatte umzugehen. Sie waren in der Lage, Formen schöpferisch zu gestalten, und schufen Schönes und Zweckmäßiges in idealen und vollkommenen Proportionen: zuerst zeichnerisch auf dem Papier und dann in der Ausführung. Als perfekte Organisatoren waren sie auch fähig, Transporte, Hebemaschinen, Rollen und Flaschenzüge auf den riesigen Baustellen sinnvoll einzusetzen. Domenico Fontana (1543,1607) and his family , famous engineers and architects from Ticino, in the service of the Pope and the King. 400 years ago, in 1607, the "ingegniere maggiore del Regno" (the Senior Engineer of the Kingdom), Domenico Fontana, died in Naples and was given a ceremonial burial in the church of Saint Anna of Lombardi. He was born in 1543 in Melide on Lake Lugano, the son of Sebastiano Fontana and his wife Domenica, née Paerino. When they were still young, the Fontanas , Domenico, his brothers Giovanni and Marsilio and a nephew, Carlo Maderno, who was born in Capologo at the lower end of Lake Lugano , set off to seek their fortune in Rome. The foreign provenance of the "comacini" from Ticino , master craftsmen from the diocese of Como, as it was at that time, was characteristic of the architecture of the imposing churches, palaces and residences that prevailed in the second half of the 16th and the start of the 17th century and which was dominated by non-Romans. Away from home, along with numerous others, including Francesco Borromini, a pupil and colleague of Domenico's nephew Carlo Maderno, they had achieved success and fame and were held in great regard. Originally, the immigrants from Ticino had mostly been taught to work with their hands (they were plasterers, stone carvers or masons) and the most skilled of them progressed to become master craftsmen, architects or engineers. By continuing their training, the Fontanas became familiar with the use of square and compasses and measuring staffs. They were able to use shape creatively, and built beautiful and useful objects in ideal and perfect proportion, first drawing the designs on paper and then executing them. They were also highly skilled organisers and were able to use transporters, lifting gear, rollers and pulleys to good effect on the huge building sites. [source]

    Management and Organizational Philosophies and Practices as Stimulants or Blocks to Creative Behavior: A Study of Engineers

    Göran Ekvall
    First page of article [source]

    Book Review: Numerical Methods for Scientists and Engineers.

    By H. M. Antia
    No abstract is available for this article. [source]

    Critical issues series: Summaries from climate change presentations

    Article first published online: 20 APR 200
    The American Institute of Chemical Engineers (AIChE) debuted its Critical Issues Series, which is "designed to establish dialogue between and among people and organizations with differing views," at the Spring National Meeting in New Orleans last March. The initial installment was entitled "Energy and a Sustainable Planet," and featured presentations on Climate Change, Alternative Energy Options, and the Viability of Nuclear Power. Below are brief summaries from three other talks given at the session on climate change. You can view a Webcast of these presentations at [source]

    AIChE offers technological insights to the public policy debate on global climate change

    David E. Gushee
    Global climate change has been a major issue on the national political agenda since 1988. Several Committees on Capitol Hill conducted hearings concerning the heat waves then searing the nation. Testimony by several well-regarded scientists at those hearings that "we ain't seen nothing yet" led to impressive headlines in the national media. Since then, unusually high temperatures, a succession of forecasts of serious negative impacts from the projected continued warming, and well-publicized Congressional hearings led to the creation of the United Nation's Framework Convention on Climate Change (FCCC) and its Kyoto Protocol. As a result, climate change is on just about every technology organization's agenda. In 1996, the American Institute of Chemical Engineers joined the list of organizations formally responding to the issue. The Government Relations Committee (GRC) formed a Task Force on Climate Change, made up of Institute members active in a number of aspects of the issue area. The charge to the Task Force: Look for opportunities for the Institute to contribute to the public policy debate on the issue and frame position papers accordingly. The first major conclusion of the Task Force was that AIChE is not in a position to state whether or not global climate change is a real public policy problem. However, to the extent that the public policy process treats climate change as an issue, the Institute is well positioned to comment on the technical merits of proposed policy responses. The Task Force recommended this posture to the GRC, which agreed. [source]

    A critical path method for the estimation of service restoration time in power distribution systems

    C. Lakshminarayana
    Abstract Distribution systems (DSs) are invariably subjected to various types of faults, causing power blackouts to occur. Distribution Engineers have the main responsibility to minimizing the duration of these power blackouts. This minimization can be achieved by the detailed study of pre-fault load condition of the DS, isolating the faulted section, and restoring the supply to healthy sections of the DS. Hence the estimation of service restoration time (SRT) is very important in electrical distribution systems (EDS). The estimation of SRT requires detailed knowledge of the commencement time of the emergency diesel generator (EDG) in EDS and also the operating time of the various relays in EDS. This paper introduces a new concept of optimistic time (OT), pessimistic time (PT), and most likely time (MT) of starting of the EDGs in addition to the OT, PT, and MT of the operation of the relays. The proposed concept is tested on 14-bus, 17-bus, and 29-bus distribution networks. The results reveal that it is highly suitable technique for the estimation of SRT under abnormal conditions. Hence this technique can easily be improved in distribution automation/service restoration algorithms. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Prediction of crack opening stress levels for 1045 quenched and tempered steel under service loading spectra

    ABSTRACT The opening stresses of a crack emanating from an edge notch in a 1045 quenched and tempered steel specimen were measured under two different Society of Automotive Engineers (SAE) standard service load histories having different average mean stress levels. The two spectra are the Grapple Skidder history (GSH), which has a positive average mean stress, and the Log Skidder history (LSH), which has a zero average mean stress. To capture the behaviour of the crack opening stress in the material, the crack opening stress levels were measured at 900X using an optical video microscope, at frequent intervals for each set of histories scaled to two different maximum stress ranges. A crack growth analysis based on a fracture mechanics approach was used to model the fatigue behaviour of the steel specimens for the given load spectra and stress ranges. Crack growth analysis was based on an effective strain-based intensity factor, a crack growth rate curve obtained during closure-free loading cycles and a local notch strain calculation based on Neuber's rule. The crack opening stress (Sop) was modelled and the model was implemented in a fatigue notch model, and the fatigue lives of the specimens under the two different spectra scaled to several maximum stress levels were estimated. The average measured crack opening stresses were between 6 and 12% of the average calculated crack opening stresses. In the interest of simplifying the use of Sop in design, the average Sop was correlated with the frequency of occurrence of the cycle reducing the Sop to the average crack opening stress level. The use of an Sop level corresponding to the cycle causing a reduction in Sop to a level reached once per 10 cycles gave a conservative estimate of average crack opening stress for all the histories. [source]

    ,Allowed into a Man's World' Meanings of Work,Life Balance: Perspectives of Women Civil Engineers as ,Minority' Workers in Construction

    Jacqueline H. Watts
    This article discusses how women working as civil engineers within the UK construction industry perceive work,life balance and considers strategies they use to achieve this. The findings are presented of a qualitative research project that explored the experiences of women in this role, focusing on the subcultural context of a profession that is dominated by the values of presenteeism and infinite availability. A feminist post-structuralist framework is used to analyse how women negotiate their personal and professional time and the extent to which their other roles as carers and nurturers unsettle male work practices in this highly gendered profession. There are gradually increasing numbers of women in professional construction roles and their success appears to depend on being able to fit in to the dominant masculine culture of long working hours and the male pub gathering. Despite an increased presence, women's minority status in construction continues to challenge their professional identity and this is central to the conflict many face between the dual roles of corporate worker and private non-work person. [source]

    Frontier Masculinity in the Oil Industry: The Experience of Women Engineers

    Gloria E. Miller
    This study contributes to the empirical evidence in the area of gendered organizations (Martin and Collinson, 2002) and their effects on the women who work in them through an interpretive, ethnographic analysis of the oil industry in Canada, specifically Alberta. The study combines data from interviews with women professionals who have extensive employment experience in the industry, a historical analysis of the industry's development in the area and the personal contextual experience of the author. It is suggested that there are three primary processes which structure the masculinity of the industry: everyday interactions which exclude women; values and beliefs specific to the dominant occupation of engineering which reinforce gender divisions; and a consciousness derived from the powerful symbols of the frontier myth and the romanticized cowboy hero. In this dense cultural web of masculinities, the strategies that the women developed to survive, and, up to a point, to thrive, are double-edged in that they also reinforced the masculine system, resulting in short-term individual gains and an apparently long-term failure to change the masculine values of the industry. [source]

    Notice of Plagiarism: A Single Recovery Type Curve from Theis' Exact Solution

    GROUND WATER, Issue 1 2004
    Article first published online: 9 OCT 200
    Shortly after the September-October 2003 issue of the journal was mailed, three readers called our attention to similarities between the paper by N. Samani and M. Pasandi (2003, ?A single recovery type curve from Theis? exact solution,?Ground Water 41, no. 5: 602-607) and a paper published in 1980 by Ram G. Agarwal. Agarwal?s paper, ?A new method to account for producing time effects when drawdown type curves are used to analyze pressure buildup and other test data,? was published by the Society for Petroleum Engineers (1980, in Society of Petroleum Engineers 55th Annual Fall Technical Conference, September 2 1-24, Dallas, Texas: SPE Paper 9289). An investigation by the journal verified that the approach and some of the wording used in the two papers are identical. Dr. Samani and Mr. Pasandi acknowledge the similarity and offer an explanation and apology. [source]

    Development of Multiple Power Quality Supply System,

    Keiichi Hirose Member
    Abstract This paper describes the characteristics and performances of a multiple power quality supply system (MPQSS), which consists of power electronics-based voltage compensators and three types of distributed generators (DGs). Its original concept of a future power delivery system having different service levels to meet each customer or load requirement at the same time was proposed as Flexible, Reliable, and Intelligent Electrical eNergy Delivery System (FRIENDS). The effectiveness of the developed power system was measured during an actual field demonstration conducted in 2007 by the New Energy and Industrial Technology Development Organization (NEDO), Sendai, Japan. Its effectiveness in feeding four classes of alternative current (AC) and one of direct current (DC) power while meeting various customer requirements was confirmed. Some sets of test data and an analysis using the data indicate that the developed system meets all the requirements for DG-related plants and has additional benefits. The power system maintains voltage and frequency conditions without interruption in the every state, grid interconnection, islanding, and backup modes. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Incorporating Penalty Function to Reduce Spill in Stochastic Dynamic Programming Based Reservoir Operation of Hydropower Plants

    Deependra Kumar Jha Non-member
    Abstract This paper proposes a framework that includes a penalty function incorporated stochastic dynamic programming (SDP) model in order to derive the operation policy of the reservoir of a hydropower plant, with an aim to reduce the amount of spill during operation of the reservoir. SDP models with various inflow process assumptions (independent and Markov-I) are developed and executed in order to derive the reservoir operation policies for the case study of a storage type hydropower plant located in Japan. The policy thus determined consists of target storage levels (end-of-period storage levels) for each combination of the beginning-of-period storage levels and the inflow states of the current period. A penalty function is incorporated in the classical SDP model with objective function that maximizes annual energy generation through operation of the reservoir. Due to the inclusion of the penalty function, operation policy of the reservoir changes in a way that ensures reduced spill. Simulations are carried out to identify reservoir storage guide curves based on the derived operation policies. Reservoir storage guide curves for different values of the coefficient of penalty function , are plotted for a study horizon of 64 years, and the corresponding average annual spill values are compared. It is observed that, with increasing values of ,, the average annual spill decreases; however, the simulated average annual energy value is marginally reduced. The average annual energy generation can be checked vis-à-vis the average annual spill reduction, and the optimal value of , can be identified based on the cost functions associated with energy and spill. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Design of A New Vibration Transducer for Implantable Middle Ear Hearing Devices

    Ki Woong Seong Non-member
    Abstract A new vibration transducer was developed for implantable middle ear hearing devices (IMEHDs). It comprises two permanent magnets positioned inside three coils. The transducer maximizes the interaction between the magnetic fields of the two magnets and the electrical current flowing through the coils. Further, the transducer is robust to external magnetic fields because the magnetic fields inside it are symmetrical. The frequency response was simulated by finite element analysis (FEA). The vibrational displacement of the proposed transducer is 6 dB greater than those of the differential floating mass transducer (DFMT) and the floating mass transducer (FMT). On the basis of these results, a prototype was fabricated and its frequency response was experimentally investigated and compared with simulation results. Finally, it is shown that the proposed transducer has a higher vibrational displacement than the older ones. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Remote Monitoring Integrated State Variables for AR Model Prediction of Daily Total Building Air-Conditioning Power Consumption

    Chuzo Ninagawa Member
    Abstract It is extremely difficult to predict daily accumulated power consumption of the entire building air-conditioning facilities because of a huge number of variables. We propose new integrated state variables, i.e. the daily operation amount and the daily operation-capacity-weighted average set temperature. Taking advantage of a remote monitoring technology, time series data of the integrated state variables were collected and an autoregressive (AR) model prediction for the daily total power consumption has been tried. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    A White LED Driver Using a Buck,Boost Converter

    Kei Eguchi Member
    Abstract For mobile backlighting applications, a white LED (WLED) driver using a buck,boost converter is proposed in this letter. Unlike conventional converters using boost converters, 2×/1.5× charge pumps, and so on, the proposed converter offers the negative stepped-down voltage to drive the LED's cathode only when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike the LED backlight using charge pumps, the proposed converter can adjust the output voltage by controlling the duty factor of the clock pulse. Thus, the proposed converter can realize high power efficiency. The validity of the proposed converter is confirmed by simulations and experiments. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Thermally Stimulated Currents of SiO2/Low-density Polyethylene Micro- and Nanocomposites

    Yi Yin Non-member
    Abstract Composite samples of low-density polyethylene (LDPE)/nano-SiO2 and LDPE/micro-SiO2 were prepared with the method of double-solution mixture. Depolarization currents of all samples were investigated with thermally stimulated depolarization current (TSDC). It was found that the currents of both composites increased with the loading level of nano-SiO2 and/or micro-SiO2, and that the peak width of each composite is greater than that of pure LDPE. In addition, the peak position of the nanocomposite shifts as the loading level increases, while that of the microcomposite does not shift significantly. In order to understand activation energy of both composites and pure LDPE, the initial-rise method was used to analyze the depolarization current. It was found that LDPE has the greatest activation energy among all samples and the activation energy of both composites decreases with increasing loading levels. Moreover, the activation energy of the nanocomposite is less than that of the microcomposite at each of the same loading level. As the nano-SiO2 loading level reaches 5.0%wt, the composite has the lowest activation energy of 0.25 eV. In addition, dielectric spectra of all samples were investigated in the range of 10,4 to 107 Hz, and it was found that the peak position of loss tangent varied consistently with the TSDC curves as the loading levels of nano-SiO2 and/or micro-SiO2 were increased. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Effect of Traps on Carrier Injection and Transport in Organic Field-effect Transistor

    Martin Weis Non-member
    Abstract This study illustrates effect of traps on the charge injection and transport in the organic field-effect transistor (OFET). Here are included silicon nanoparticles (NPs) on a semiconductor-gate insulator interface, which work as trapping centers of charge carriers. Charge transport and injection phenomena are investigated by electrical measurements in presence of traps with designed densities. We find that OFETs with a low concentration of intrinsic carriers, such as a pentacene, are extremely sensitive to the internal electric fields. A significant threshold voltage shift due to trapped charge is observed, with a possibility to tune it by controlling the NP density. We demonstrate that the NP film can serve to design the amount of the accumulated charge in OFET and thus change the space-charge-limited conditions to the injection-limited conditions. A detailed analysis of pentacene OFET based on dielectric properties and the Maxwell-Wagner model reveals the internal electric field created by NPs. Additionally, the effect of NPs is discussed with respect to effective mobility, and its decrease is related to deceleration of carrier propagation by the trapping effect as well as low injection due to the increase of the carrier injection barrier by the internal field. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Space Charge Measurement in MgO/LDPE Nanocomposite up to Breakdown under DC Ramp Voltage

    Yoshinobu Murakami Member
    Abstract To understand the basic electric properties of nanosized magnesium oxide (MgO)/low-density polyethylene (LDPE) nanocomposites under an applied DC voltage, the DC breakdown strength and space charge up to the breakdown under a DC ramp voltage were investigated. Compared to that of the LDPE sample, the sample containing a MgO nanofiller (hereafter, called a nanocomposite) had a higher DC breakdown strength. In the case of the LDPE sample, the homo charges, which contained a large negative charge and a small positive charge, were only observed near the electrodes just prior to breakdown. However, in the case of the nanocomposite sample, the positive charge increased as the average field increased until the average field reached a certain value. After that, the positive charge decreased as the average field increased until breakdown occurred. The field enhancement rate (=maximum field/average field) of the nanocomposite sample increased with the average field, until it became saturated. After peaking, the field enhancement rate of the nanocomposite sample decreased as the average field increased. These observations suggest that, instead of the MgO nanofiller suppressing the electronic avalanche, it suppresses the conduction current, which was determined by the space charge, leading to the higher DC breakdown strength. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    xBCI: A Generic Platform for Development of an Online BCI System

    I Putu Susila Non-member
    Abstract A generic platform for realizing an online brain,computer interface (BCI) named xBCI was developed. The platform consists of several functional modules (components), such as data acquisition, storage, mathematical operations, signal processing, network communication, data visualization, experiment control, and real-time feedback presentation. Users can easily build their own BCI systems by combining the components on a graphical-user-interface (GUI) based diagram editor. They can also extend the platform by adding components as plug-ins or by creating components using a scripting language. The platform works on multiple operating systems and supports parallel (multi-threaded) data processing and data transfer to other PCs through a network transmission control protocol/internet protocol or user datagram protocol (TCP/IP or UDP). A BCI system based on motor imagery and a steady-state visual evoked potential (SSVEP) based BCI system were constructed and tested on the platform. The results show that the platform is able to process multichannel brain signals in real time. The platform provides users with an easy-to-use system development tool and reduces the time needed to develop a BCI system. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Design of a Singlet Lens and the Corresponding Aberration Correction Approaches for Cell Phone Camera

    Yupeng Zhang Member
    Abstract A singlet lens model that is designed for future cell phone camera is discussed. The proposed lens model unavoidably introduces significant optical aberration because of its high field angle (maximum field angle 48°). To correct the aberrations, traditional paraxial aberration and third-order Seidel aberration are no longer applicable because the accuracy will decline dramatically when the field angle reaches a high value. In this paper, the main objective is to find an improved first-order aberration equation and an improved third-order Seidel aberration equation using field-dependent coefficients to correct lateral chromatic aberration (LAT) and distortion, respectively, for a high-field-angle singlet lens. The simulation results suggest that improved higher order aberration equations are more accurate to represent real aberrations than the lower order case. However, the chromatic aberration is still visible in the resultant images even though LAT is corrected, because of the differences of blur between different colors caused by axial chromatic aberration (AX) and other monochromatic aberrations such as field curvature. This poses a new research topic as our future work. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Relationship between Contact Voltage Drop and Frictional Coefficient under High-current Sliding Contact

    Takahiro Ueno Member
    Abstract Large DC motors are used in various industrial applications. These motors repeatedly generate arcs between the brush and commutator, because the load change is intense and the current value is also large. In particular, for the case in which the current is concentrated on a part of the brush, brush burnout may occur as a result of overcurrent. Therefore, excellent brushes to withstand arc generation and with good electrical properties are required. In the present paper, we discuss the relation between contact voltage drop and frictional wear for electrical sliding contacts when high currents flow to the brush. Specifically, we investigate the means by which to prevent brush burnout when high-current flows to the brush. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Optimization of Train Speed Profile for Minimum Energy Consumption

    Masafumi Miyatake Member
    Abstract The optimal operation of railway systems minimizing total energy consumption is discussed in this paper. Firstly, some measures of finding energy-saving train speed profiles are outlined. After the characteristics that should be considered in optimizing train operation are clarified, complete optimization based on optimal control theory is reviewed. Their basic formulations are summarized taking into account most of the difficult characteristics peculiar to railway systems. Three methods of solving the formulation, dynamic programming (DP), gradient method, and sequential quadratic programming (SQP), are introduced. The last two methods can also control the state of charge (SOC) of the energy storage devices. By showing some numerical results of simulations, the significance of solving not only optimal speed profiles but also optimal SOC profiles of energy storage are emphasized, because the numerical results are beyond the conventional qualitative studies. Future scope for applying the methods to real-time optimal control is also mentioned. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Fixed Energy Storage Technology Applied for DC Electrified Railway

    Takeshi Konishi Member
    Abstract The fixed energy storage system solves the problem of rising energy costs by reducing primary energy consumption. Without a fixed energy storage system, the energy generated by a braking vehicle would be simply converted into waste heat by its braking resistors if no other vehicles are powered simultaneously. Because, as a rule, such synchronized braking and powering cannot be coordinated, the energy storage system stores the energy generated during braking and discharges it again when a vehicle is powered. This greatly reduces primary energy demand in the substation. However, in addition to this energy saving, the energy storage system contributes to the reduction of CO2 emissions. The energy storage system also stabilizes the system voltage. Recent years have witnessed an advance in the energy storage media technology. Developments of energy storage media, lithium ion battery, nickel-metal hydride battery, and electric double-layer capacitors (EDLCs) have been remarkable. This study introduces technologies of fixed energy storage system applicable for DC electrified railway in Japan, and describes two examples of charge/discharge characteristics. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Diffusion Characteristics of VOCs Indoors

    Shin-ichi Shibata Student Member
    Abstract Diffusion characteristics of volatile organic compounds (VOCs) were investigated indoors using tin oxide gas sensors. The chemicals cause various kinds of symptoms in humans, for example, the sick house syndrome. In this study, eight sensors were installed in a vertical direction and on a plane surface. These sensors were of the same type. The VOC is placed in a generation source, and the sensor output increases as the chemical diffuses. The sensor output becomes higher as the concentration increases. The following chemicals were tried as air pollutants: formaldehyde, toluene, and xylene. The sensor output changes in short, quick steps by slight fluctuations of the wind velocity. Therefore, the differential characteristic of the sensor output was adopted and the noise component was removed as far as possible. A threshold time tth to the characteristic was set up. It is assumed that the examining chemical reaches the installed sensor point in a time greater than this time. The new speed of arrival is proposed using the threshold time. The speed s [cm/min] is indicated using the distance d and the reaching time tth, namely, s = d/tth. Here, d means the distance between the sensor position and the polluting source. As a result, the speed for the sensor that is installed near the ceiling (at a height of 260 cm from the floor) is the highest. And, it became obvious that s was larger for the chemical with a smaller molecule. The speed of formaldehyde for the sensor installed near the ceiling was 700 cm/min and that for the sensor installed at the height of 100 cm from the floor was 370 cm/min. There is almost a two times difference in the speed. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    High-Speed and Wide-Angle Deflection Optical MEMS Scanner Using Piezoelectric Actuation

    Takayuki Iseki Member
    Abstract A fast and wide deflection silicon-resonant torsional optical scanner driven by a piezoelectric actuator has been developed and patented. The scanner is composed of a 1-mm square mirror and two pairs of torsion beams and arms fabricated using microelectromechanical system (MEMS) processing of a silicon-on-insulator (SOI) wafer. According to calculations, at the same resonant driving frequency, the maximum principal stress of this structure was about one-third smaller than that of the usual structure having one pair of torsion beams. We achieved high frequency scanning of the optical beam with a large angular deflection up to 54° at 38 kHz with a 5 V peak-to-peak applied voltage using the bulk piezoelectric stack actuator, and up to 17° at 38 kHz with a 25 V peak-to-peak voltage using the unimorph actuator of a zinc oxide (ZnO) thin film. These results show that this scanner has the ability to perform the horizontal scanning for high-resolution extended graphics array (XGA) or super extended graphics array (SXGA) laser display. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]