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Sample records for asynchronous traction engines

  1. Zero Dynamics Analysis for Inverse Decoupling Control of Asynchronous Traction Motor

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    Haiying Dong

    2013-07-01

    Full Text Available Considering the problem for inverse system method in EMU AC induction traction motor linear decoupling, the zero dynamics subsystem will be separated from the original dynamic system through coordinate transformation. Firstly, a getting method for zero dynamics of the multiple input multiple output nonlinear system is discussed when γ<n. Second, the zero dynamics analysis for five order nonlinear model of asynchronous traction motor which base on the stationary coordinate system is given by using inverse decoupling method. The analysis results show that if the stability of the zero dynamics can be ensured, then the entire linearization of original nonlinear system is not necessary, need only partial linearization which effect on the external dynamic portion. The inverse decoupling process of asynchronous traction motor can be simplified by this conclusion.

  2. Study of the asynchronous traction drive's operating modes by computer simulation. Part 1: Problem formulation and computer model

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    Pavel KOLPAHCHYAN

    2015-06-01

    Full Text Available In this paper, the problems arising from the design of electric locomotives with asynchronous traction drive (with three-phase AC induction motors are considered as including the debugging of control algorithms. The electrical circuit provides the individual (by axle control of traction motors. This allows realizing the operational disconnection/connection of one or more axles in the automatic mode, with account of actual load. In perspective, the evaluation of locomotive's energy efficiency at the realization of various control algorithms must be obtained. Another objective is to research the dynamic processes in various modes of the electric locomotive operation (start and acceleration, traction regime, coasting movement, wheel-slide protection, etc. To solve these problems, a complex computer model based on the representation of AC traction drive as controlled electromechanical system, is developed in Part 1. The description of methods applied in modeling of traction drive elements (traction motors, power converters, control systems, as well as of mechanical part and of "wheel-rail" contact, is given. The control system provides the individual control of the traction motors. Part 2 of the paper focuses on the results of dynamic processes modeling in various modes of electric locomotive operation.

  3. BACKGROUNDS OF EXPERIMENTAL INVESTIGATION OF ELECTROMAGNETIC COMPATIBILITY OF TRACTION ASYNCHRONOUS ELECTRIC DRIVES IN THE STRUCTURE OF DC TRACTION POWER SUPPLY SYSTEM

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    YU. S. Bondarenko

    2014-04-01

    Full Text Available Purpose. Application of physical modeling as a tool for research of any events or systems is becoming more widespread, including the field of railway transport. At the same time the adequacy of results that can be obtained, depends largely on the similarity degree of the physical model to real system. From the standpoint of the traction asynchronous electric drive (TAED research together with the traction power supply system research, the similarity can not be determined by the direct proportion of the parameters, because the processes nature accompanying the operation of these systems is non-linear. These features should be taken into account in the experimental setup, the basis for constructing of which is establishing of the system similarity that defines the purpose of this paper. Methodology. At the heart of the experimental setup creation laid reproduction of processes of energy transformation in the system of the DC traction power supply. Determination of the similarity degree of the proposed facility to the real system was carried out using the basic theorems of the similarity theory, their additional provisions on the complexity and nonlinear systems, as well as elements of mathematical analysis. Findings. According to the results of work: 1 The block diagram, the energy conversion mechanism of which is similar to the real system was received. This scheme is the basis of experimental setup, built in the future for the study of electromagnetic compatibility of TAED in the structure of DC traction electric power supply system. 2 Similarity of obtained structural scheme with the real system with the mechanism definition of calculating the scaling relations was established. Originality. In the process of establishing the similarity a simplified method for determining the scaling relations for nonlinear systems was suggested. They are identical in their structure components, but have different capacities. Practical value. Experimental

  4. THE SIX-WHEEL FRIGHT TRUCK LOCOMOTIVE OF DOUBLE DELIVERY USES RADIO-FREQUENCY TRANSFER WITH PADDING AND ASYNCHRONIZED TRACTION IMPELLENTS

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    M. H. Visin

    2010-10-01

    Full Text Available Our research offers a new perspective loading pattern of the 12-wheel double-feed freight electric locomotive with the asynchronous tractive motor using an adapter transformer with the high-frequency uncoupler. This will make it possible to decrease the traction-feeding transformer mass 2.3 times, to remove the current pulse advancing on the track circuit and therefore the influence on the work of the ALSE and CBS. So the railway traffic safety will be increased considerably.

  5. Online-BSEE (Online Bachelor of Science in Electrical Engineering): An Asynchronous Online Electrical Engineering Degree Program with Laboratory

    Science.gov (United States)

    Tang, Wendy; Westgate, Charles; Liu, Pao-Lo; Gouzman, Michael

    2014-01-01

    The Online Bachelor of Science in Electrical Engineering is a collaborative effort among three University Centers at SUNY (State University of New York), namely Stony Brook, Binghamton, and Buffalo. The program delivers the complete electrical engineering curriculum at the bachelor level to students online and asynchronously. Students, however,…

  6. Calculation and Analysis on Electro-magnetic Field of the Asynchronous Traction Motor for Freight Locomotive%货运机车异步牵引电机电磁场计算与分析

    Institute of Scientific and Technical Information of China (English)

    阮鸿芳; 于海涛

    2015-01-01

    Taking the AC asynchronous traction mo-tor of the HXD1C high-power locomotive as example, the 2D mathematic model of the electro-magnetic field was established and its solved region was determined either. The finite element method was applied to calculate the electro-magnetic parameters of the traction motor while the calculated result was compared with the actually-test data, and then, came the beneficial conclusion.%以大功率交流传动H X D1C机车用异步牵引电机为例,建立电机二维电磁场数学模型,并确定其求解域.利用有限元方法,计算牵引电机电磁参数,并将计算结果与实测数据进行对比,得出一些有益的结论.

  7. Traction coefficient in a roller-inner ring EHD contact in a jet engine roller bearing

    Energy Technology Data Exchange (ETDEWEB)

    Sottomayor, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Campos, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Seabra, J. [Dept. de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto (Portugal)

    1997-08-01

    A simplified non-newtonian EHD model developed previously is used for the analysis of a roller-inner ring contact in a jet engine roller bearing. The lubricant behaves according to the viscoelastic rheological model, with a Ree-Eyring fluid, and the lubricant parameters are function of the pressure, temperature and rolling speed. The traction coefficient results obtained with this model are compared with previous experimental results obtained in a twin-disk machine. Finally, the influence of the operating conditions (pressure, temperature, rolling speed and slide-to-roll ratio) and of the waviness of the contacting surfaces, on the traction coefficient inside the roller-inner ring contact, is analysed. (orig.)

  8. ONCE AGAIN ABOUT DETERMINATION OF SAVING OF ENERGY FOR TRACTION DUE TO PARTIAL CUT–OFF OF TRACTION ENGINES OF ELECTRIC ROLLING STOCK

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    G. K. Getman

    2013-09-01

    Full Text Available Purpose. In general the well known methods for determination of energy saving due to the partial traction engines cut-off based on their comparison to efficiency coefficient or to the power of energy losses do not allow objective estimation of efficiency of these measures and in a number of cases result in erroneous results and errors. The search for new more advanced methods for determination of energy saving at the partial cut-off of the traction engines is needed. Methodology. The method of calculation determination of energy saving when partial cutting-off of the traction engines is offered. It is based on the use of rationality coefficient as the loading mode of the electric power consumption for the measuring instrument of transportation activity. Findings. Using the given mathematical expressions it is possible to determine the energy saving in both the relative and absolute values and set the terms (motion speed and route gradient, under which the energy saving will take place. Originality. The method of the task solving, which is based on the evaluation of energy consumption differences for the compared variants (not on the comparison of efficiency coefficient or differences of power of energy losses is offered. Practical value. The given methodology allows obtaining more exact conclusions in relation to the electric power consumption, as the comparison of energy losses power or the efficiency coefficient does not determine precisely the electric power consumption for traction. Therefore the conclusions based on the comparison of power of energy losses or efficiency coefficient can appear inexact.

  9. Research of the multipolar induction traction frequency regulated motor

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    V. Ia. Bespalov

    2014-01-01

    Full Text Available The paper considers the application features of traction induction electric motors in transmissions of vehicles. It shows that one of important stages in their designing is to choose the number of poles. In traction electric drives engines with the raised number of poles without comprehensive assessment of such solution are often applied. The paper investigates dynamic and power characteristics of the multi-polar traction asynchronous engine (TAE designed and made for using in the individual electric drive of heavy-load wheeled cars. The basic functional elements of the model to simulate the electric drive in Matlab environment with the Simulink and SimPower Systems applications in the structure with vector control are described, and the simulation modeling results of its dynamic mechanical characteristics are provided. It is established that because of increased alternating frequency of currents of the multi-polar engine in the range of high speeds there is an excessive decrease in the torque and the requirement for constancy of the target capacity, corresponding to the specified traction characteristic is not fulfilled. It is a consequence of the waveform distortion of engine phase current in the range of high speeds because of incapability of the power source to compensate an increasing EMF of movement as the speed continues to grow.The paper studies the influence of increased current frequencies on the additional losses in the engine. The analysis of electromagnetic field penetration depth in the copper conductor of stator winding at high frequency allowed us to establish a significant skin – effect. The quantitative assessment is given to this phenomenon by results of numerical calculation of electromagnetic field distribution in a stator groove. Significant increase in additional losses in the engine is established, and estimates of flow loss extent because of damping actions of eddy currents in the laminated steel of stator at

  10. RESEARCH INTO VALVE-ENGINE TRANSDUCERS OF BRUSHLESS SYNCHRONOUS AND ASYNCHRONIZED MACHINES IN A CIRCUIT SIMULATION SYSTEM.

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    A.M. Galynovskiy

    2013-10-01

    Full Text Available Designing features for valve-engine transducers of brushless synchronous and asynchronized machines are described. Global analysis of research results on the transducer models in a MicroCap circuit simulation system is made, recommendations on the simulation system application in both scientific research and educational process given.

  11. Control algorithms for single inverter dual induction motor system applied to railway traction; Commande algorithmique d'un systeme mono-onduleur bimachine asynchrone destine a la traction ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Pena Eguiluz, R.

    2002-11-15

    The goal of this work concerns the modelling and the behaviour characterisation of a single inverter dual induction motor system applied to a railway traction bogie (BB36000) in order to concept its control. First part of this job is dedicated to the detailed description of overall system. The influence analysis of the internal perturbations (motor parameters variation) and, external perturbations (pantograph detachment, adherence loss, stick-slip) of the system have made considering the field oriented control applied to each motor of the bogie (classical traction structure). vi In a second part, a novel propulsion structure is proposed. It is composed by a single pulse-width modulated two level voltage source inverter. It supplies two parallel connected induction motors, which generate the transmitted traction force to the bogie wheels. The locomotive case represents the common load for the two motors. Several co-operative control strategies (CS) are studied. They are: the mean CS, the double mean CS, the master - slave switched CS and, the mean differential CS. In addition, an appropriated electric modes observer structure for these different controls has studied. These controls have validated applying the perturbations to the models using the solver SABER. This special approach is equivalent to quasi-experimentation, because the mechanical and the electrical system components have modelled using MAST language and, the sample control has created by a C code programme in the SABER environment. Third part is dedicated to the mechanical sensor suppression and, its adaptation in the cooperative control strategies. The partial speed reconstruction methods are: the fundamental frequency relation, the mechanical Kalman filter, the variable structure observer and the MRAS. Finally, the hardware system configuration of the experimental realisation is described. (author)

  12. Substrates with engineered step changes in rigidity induce traction force polarity and durotaxis.

    Science.gov (United States)

    Breckenridge, Mark T; Desai, Ravi A; Yang, Michael T; Fu, Jianping; Chen, Christopher S

    2014-03-01

    Rigidity sensing plays a fundamental role in multiple cell functions ranging from migration, to proliferation and differentiation(1-5). During migration, single cells have been reported to preferentially move toward more rigid regions of a substrate in a process termed durotaxis. Durotaxis could contribute to cell migration in wound healing and gastrulation, where local gradients in tissue rigidity have been described. Despite the potential importance of this phenomenon to physiology and disease, it remains unclear how rigidity guides these behaviors and the underlying cellular and molecular mechanisms. To investigate the functional role of subcellular distribution and dynamics of cellular traction forces during durotaxis, we developed a unique microfabrication strategy to generate elastomeric micropost arrays patterned with regions exhibiting two different rigidities juxtaposed next to each other. After initial cell attachment on the rigidity boundary of the micropost array, NIH 3T3 fibroblasts were observed to preferentially migrate toward the rigid region of the micropost array, indicative of durotaxis. Additionally, cells bridging two rigidities across the rigidity boundary on the micropost array developed stronger traction forces on the more rigid side of the substrate indistinguishable from forces generated by cells exclusively seeded on rigid regions of the micropost array. Together, our results highlighted the utility of step-rigidity micropost arrays to investigate the functional role of traction forces in rigidity sensing and durotaxis, suggesting that cells could sense substrate rigidity locally to induce an asymmetrical intracellular traction force distribution to contribute to durotaxis.

  13. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

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    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  14. Control concept for a hybrid engine test device composed of a water vortex brake and an asynchronous machine; Regelungskonzept fuer einen Hybrid-Motorenpruefstand

    Energy Technology Data Exchange (ETDEWEB)

    Maeenpaeae, A. [ABB Automation Products, Mannheim (Germany); Fischer, G. [Technische Univ. Darmstadt (Germany)

    2000-07-01

    New environmental laws require lower exhaust limits of motor vehicles all over the world. To test these limits, drive-cycle tests are performed on engine test devices. Future laws will require the simulation od downhill driving, which requires extensive changes to the engine test devices. Hybrid test devices with a water vortex brake and an asynchronous machine could be advantageous. A new control concept for those hybrid test devices is described here. (orig.) [German] Neue Umweltgesetze druecken weltweit die Abgasgrenzwerte von Automobilen nach unten. Zur Ueberpruefung dieser Grenzwerte dienen Fahrzyklus-Testreihen auf Motorenpruefstaenden. Kuenftige Vorschriften erfordern dabei bald die Simulation des 'Schiebebetriebs' (wie bei Bergabfahrten). Das erfordert aufwendige Umruestungen bei den Motorenpruefstaenden. Eine preisguenstige Loesung stellen Hybrid-Pruefstaende aus einer Wasserwirbelbremse und einer Asynchron-Maschine dar. Ein neues Regelkonzept dafuer wird hier beschrieben. (orig.)

  15. Effect of turbo charger system on engine fuel consumption and tractor power and traction (ITM475, ITM485 and ITM800

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    Kh PashaiHulasu

    2015-09-01

    Full Text Available Introduction: Tractors are considered as the main power generators in mechanized agriculture. Hence, the experts and engineers in tractor manufacturing of the country, are required to focus on developing and designing new features in tractor manufacturing. This must be, of course, paralleled with the economic aspects. Achieving this goal, Iran Tractor Manufactories Co., (ITMCO has designed and developed tractors equipped with turbochargers. This has been performed on ITM800 & ITM485 models, according to world standards. The turbocharger system, with harnessing of lost energy in engine output fumes, compresses the air entering the engine and more air enters the cylinder. This will cause the engine to burn fuel more efficiently and thus produce more power. Materials and Methods: This study has been carried out on ITM485 & ITM800 tractors (with turbocharger system and ITM285 & ITM475 tractors (without turbocharger system to assure the improvement of engine performance and compare them employing OECD world standards. Experiments were performed in the concrete runway of Tabriz Tractor Manufacturing Company. For experiments, a dynamometer was used to measure the traction force between two tractors, a measuring unit for fuel, a thermometer unit and a timer to measure the quantities of fuel consumption, drawbar force and power. For drawbar traction test, each of the tested tractors pulled the rear tractor in different gears and the dynamometer between these 2 tractors recorded the tractors traction force by data loggers. To measure tractors fuel consumption, a measuring unit of fuel (VDO - EDM 1404 was used that calculated the flow rate in the path of fuel from the fuel tank to the engine and the return path from the engine to the fuel tank and showed the quantity of fuel consumption in liters per hour digitally. Results and Discussion: In comparison of traction power and force of tractors with turbochargers and without turbochargers in different gears

  16. Advanced Integrated Traction System

    Energy Technology Data Exchange (ETDEWEB)

    Greg Smith; Charles Gough

    2011-08-31

    The United States Department of Energy elaborates the compelling need for a commercialized competitively priced electric traction drive system to proliferate the acceptance of HEVs, PHEVs, and FCVs in the market. The desired end result is a technically and commercially verified integrated ETS (Electric Traction System) product design that can be manufactured and distributed through a broad network of competitive suppliers to all auto manufacturers. The objectives of this FCVT program are to develop advanced technologies for an integrated ETS capable of 55kW peak power for 18 seconds and 30kW of continuous power. Additionally, to accommodate a variety of automotive platforms the ETS design should be scalable to 120kW peak power for 18 seconds and 65kW of continuous power. The ETS (exclusive of the DC/DC Converter) is to cost no more than $660 (55kW at $12/kW) to produce in quantities of 100,000 units per year, should have a total weight less than 46kg, and have a volume less than 16 liters. The cost target for the optional Bi-Directional DC/DC Converter is $375. The goal is to achieve these targets with the use of engine coolant at a nominal temperature of 105C. The system efficiency should exceed 90% at 20% of rated torque over 10% to 100% of maximum speed. The nominal operating system voltage is to be 325V, with consideration for higher voltages. This project investigated a wide range of technologies, including ETS topologies, components, and interconnects. Each technology and its validity for automotive use were verified and then these technologies were integrated into a high temperature ETS design that would support a wide variety of applications (fuel cell, hybrids, electrics, and plug-ins). This ETS met all the DOE 2010 objectives of cost, weight, volume and efficiency, and the specific power and power density 2015 objectives. Additionally a bi-directional converter was developed that provides charging and electric power take-off which is the first step

  17. Follicular traction urticaria*

    Science.gov (United States)

    Duman, Hatice; Topal, Ilteris Oguz; Kocaturk, Emek

    2016-01-01

    Inducible urticaria is a heterogeneous subgroup of chronic urticarias caused by a wide variety of environmental stimuli, such as exercise, cold, heat, pressure, sunlight, vibration, and water. A new term, follicular traction urticaria, was suggested as an unusual form of inducible urticarias. We report a patient who was diagnosed with follicular traction urticaria.

  18. Asynchronous networks and event driven dynamics

    Science.gov (United States)

    Bick, Christian; Field, Michael

    2017-02-01

    Real-world networks in technology, engineering and biology often exhibit dynamics that cannot be adequately reproduced using network models given by smooth dynamical systems and a fixed network topology. Asynchronous networks give a theoretical and conceptual framework for the study of network dynamics where nodes can evolve independently of one another, be constrained, stop, and later restart, and where the interaction between different components of the network may depend on time, state, and stochastic effects. This framework is sufficiently general to encompass a wide range of applications ranging from engineering to neuroscience. Typically, dynamics is piecewise smooth and there are relationships with Filippov systems. In this paper, we give examples of asynchronous networks, and describe the basic formalism and structure. In the following companion paper, we make the notion of a functional asynchronous network rigorous, discuss the phenomenon of dynamical locks, and present a foundational result on the spatiotemporal factorization of the dynamics for a large class of functional asynchronous networks.

  19. The bond-graph design of a motor used for electrical traction

    Directory of Open Access Journals (Sweden)

    Adriana Grava

    2009-10-01

    Full Text Available In this paper the asynchronous motorwith cage, used for electrical traction is studied andanalyzed. For this motor we realized the associatedbond-graph, we pointed out the equations thatdescribe this motor, and we analyzed the electricaland mechanical features of this motor, by using thesimulation program 20 SIM, in order to improve theperformances of this motor even from the early stageof design.

  20. Compositional asynchronous membrane systems

    Institute of Scientific and Technical Information of China (English)

    Cosmin Bonchis; Cornel Izbasa; Gabriel Ciobanu

    2007-01-01

    This paper presents an algorithmic way of building complex membrane systems by coupling elementary membranes. Its application seems particularly valuable in the case of asynchronous membrane systems, since the resulting membrane system remains asynchronous. The composition method is based on a handshake mechanism implemented by using antiport rules and promoters.

  1. Asynchronous ASCII Event Count Status Code

    Science.gov (United States)

    2012-03-01

    IRIG STANDARD 215-12 TELECOMMUNICATIONS AND TIMING GROUP ASYNCHRONOUS ASCII EVENT COUNT STATUS CODES...Inter-range Instrumentation Group ( IRIG ) Standard for American Standard Code for Information Interchange (ASCII)-formatted EC status transfer which can be...circuits and Ethernet networks. Provides systems engineers and equipment vendors with an Inter-range Instrumentation Group ( IRIG ) Standard for American

  2. Low latency asynchronous interface circuits

    Energy Technology Data Exchange (ETDEWEB)

    Sadowski, Greg

    2017-06-20

    In one form, a logic circuit includes an asynchronous logic circuit, a synchronous logic circuit, and an interface circuit coupled between the asynchronous logic circuit and the synchronous logic circuit. The asynchronous logic circuit has a plurality of asynchronous outputs for providing a corresponding plurality of asynchronous signals. The synchronous logic circuit has a plurality of synchronous inputs corresponding to the plurality of asynchronous outputs, a stretch input for receiving a stretch signal, and a clock output for providing a clock signal. The synchronous logic circuit provides the clock signal as a periodic signal but prolongs a predetermined state of the clock signal while the stretch signal is active. The asynchronous interface detects whether metastability could occur when latching any of the plurality of the asynchronous outputs of the asynchronous logic circuit using said clock signal, and activates the stretch signal while the metastability could occur.

  3. Mechanical properties evolution of a PLGA-PLCL composite scaffold for ligament tissue engineering under static and cyclic traction-torsion in vitro culture conditions.

    Science.gov (United States)

    Kahn, Cyril J F; Ziani, Kahina; Zhang, Ye Min; Liu, Jian; Tran, Nguyen; Babin, Jérôme; de Isla, Natalia; Six, Jean-Luc; Wang, Xiong

    2013-01-01

    This study aims to investigate the in vitro degradation of a poly(L-lactic-co-glycolic acid)-poly(L-lactic-co-ϵ-caprolactone) (PLGA-PLCL) composite scaffold's mechanical properties under static culture condition and 2 h period per day of traction-torsion cyclic culture conditions of simultaneous 10% uniaxial strain and 90° of torsion cycles at 0.33 Hz. Scaffolds were cultured in static conditions, during 28 days, with or without cell seeded or under dynamic conditions during 14 days in a bioreactor. Scaffolds' biocompatibility and proliferation were investigated with Alamar Blue tests and cell nuclei staining. Scaffolds' mechanical properties were tested during degradation by uniaxial traction test. The PLGA-PLCL composite scaffold showed a good cytocompatibility and a high degree of colonization in static conditions. Mechanical tests showed a competition between two process of degradation which have been associated to hydrolytic and enzymatic degradation for the reinforce yarn in poly(L-lactic-co-glycolic acid) (PLGA). The enzymatic degradation led to a decrease effect on mechanical properties of cell-seeded scaffolds during the 21st days, but the hydrolytic degradation was preponderant at day 28. In conclusion, the structure of this scaffold is adapted to culture in terms of biocompatibility and cell orientation (microfiber) but must be improved by delaying the degradation of it reinforce structure in PLGA.

  4. Measuring Fuel Consumption of Mining Truck with Engine Traction Characteristics and Actual Road Condition%利用发动机牵引特性及实际路况测算矿山运输卡车油耗

    Institute of Scientific and Technical Information of China (English)

    刘宪权

    2015-01-01

    This paper puts forward the current problems of budgeting the fuel consumption of mining truck. Combining the actual experience,the paper discusses the main factors that impact the fuel consumption. It also offers a new method to measure the fuel consumption of mining with the engine traction characteristics and actual road conditions.%针对目前矿山运输卡车油耗环节成本测算中存在的问题,结合实际经验,讨论影响油耗的主要因素,并提出了利用发动机牵引特性及实际路况测算开采油耗的新方法,供同行参考。

  5. Asynchronized synchronous machines

    CERN Document Server

    Botvinnik, M M

    1964-01-01

    Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids” of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv

  6. Asynchronous Multiparty Computation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Geisler, Martin; Krøigaard, Mikkel

    2009-01-01

    We propose an asynchronous protocol for general multiparty computation. The protocol has perfect security and communication complexity  where n is the number of parties, |C| is the size of the arithmetic circuit being computed, and k is the size of elements in the underlying field. The protocol g...

  7. Multiparty Asynchronous Session Types

    DEFF Research Database (Denmark)

    Honda, Kohei; Yoshida, Nobuko; Carbone, Marco

    2016-01-01

    peers are directly abstracted as a global scenario. Global types retain the friendly type syntax of binary session types while specifying dependencies and capturing complex causal chains of multiparty asynchronous interactions. A global type plays the role of a shared agreement among communication peers...

  8. Asynchronous P300 BCI

    DEFF Research Database (Denmark)

    Panicker, Rajesh; Puthusserypady, Sadasivan; Sun, Ying

    2010-01-01

    An asynchronous hybrid brain-computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEP) paradigms is introduced. A P300 base system is used for information transfer, and is augmented to include SSVEP for control state detection. The proposed system has...

  9. Redundant Asynchronous Microprocessor System

    Science.gov (United States)

    Meyer, G.; Johnston, J. O.; Dunn, W. R.

    1985-01-01

    Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

  10. Experimental 3D Asynchronous Field Programmable Gate Array (FPGA)

    Science.gov (United States)

    2015-03-01

    EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) CORNELL UNIVERSITY MARCH 2015 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC...From - To) OCT 2011 – OCT 2014 4. TITLE AND SUBTITLE EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) 5a. CONTRACT NUMBER...in collaboration with Albany’s College of Nanoscale Science and Engineering. 15. SUBJECT TERMS 3D Technology, vertical interconnects, AFPGA, FPGA

  11. Vitreomacular traction syndrome

    Institute of Scientific and Technical Information of China (English)

    Shao Lei; Wei Wenbin

    2014-01-01

    Objective This study aimed to review the available literature on vitreomacular traction (VMT) syndrome and propose the future study prospect in this field.Data sources The data used in this review were mainly obtained from articles listed in Medline and Pubmed (1970-2013).The search terms were "vitreomacular traction," "optical coherence tomography," "vitrectomy," and "ocriplasmin."Study selection Articles regarding the pathophysiology,diagnosis,and treatments of VMT were selected and reviewed.Results VMT syndrome is a persistent attachment of vitreous to the macula in eyes with an incomplete posterior vitreous detachment and considered to be an uncommon status which correlated with some other macular disorders.Optical coherence tomography (OCT) can support a new way to examine and classify VMT.Nonoperative and operative intervenes on this disease have been developed recently,especially the intravitreal medical therapy.Conclusions VMT syndrome may be associated with various disorders in the macular region,depending in part on the size and strength of the residual vitreomacular adhesion.Regular OCT monitoring is recommended to detect it.Patients with asymptomatic VMT should be observed for at least 2-3 months; nonoperative treatment with ocriplasmin should be considered when disorders persist; surgery is recommended if VMT-related disease is significant.

  12. Vitreomacular Traction Syndrome

    Directory of Open Access Journals (Sweden)

    Juliana Bottós

    2012-01-01

    Full Text Available The advent of new technologies such as high definition optical coherence tomography (OCT has not only provided unprecedented imaging capabilities, but also raised the need to define concepts not yet settled and often confusing such as the vitreomacular traction (VMT syndrome. While technological advances drive us into the future by clarifying the pathophysiology of many diseases and enabling novel therapeutic options, it is at the same time necessary to review basic disease concepts in addition to definitions and classifications. VMT syndrome is implicated in the pathophysiology of a number of macular disorders, translating into a variety of anatomical and functional consequences underscoring the complexity of the condition. These macular changes are closely related to the VMT configuration and have led to proposing classification of this syndrome based on OCT findings. The size and severity of the remaining vitreomacular attachment may define the specific maculopathy. Focal VMT usually leads to macular hole formation, tractional cystoid macular edema and foveal retinal detachment, while broad VMT is associated with epiretinal membranes, diffuse retinal thickening and impaired foveal depression recovery. Despite similar postoperative visual acuity (VA in focal and broad VMT subgroups, visual improvement is greater with focal VMT because preoperative VA is frequently lower. Surgical procedures are effective to relieve VMT and improve VA in most eyes; outcomes vary with VMT morphology and the duration of symptoms.

  13. Methodology of system design in electrical engineering with Bond Graph: application on a railway traction system; Methodologie de conception systemique en genie electrique a l'aide de l'outil Bond Graph: application a une chaine de traction ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Gandanegara, G.

    2003-11-15

    In Electrical Engineering, the global analysis of systems is difficult because of their heterogeneity and their multi-domain nature. Nevertheless, this system approach is essential because it underlines couplings between elements of different physical fields. To facilitate this analysis, the unified formalism Bond Graph is used. This modeling method illustrates the energetic transfers in the system. Moreover, this methodology offers interesting solutions in terms of system analysis. Two simplification methods have been investigated and compared, i.e. the Singular Perturbations Method (SPM), based on the dynamic analysis of elements, and the Model Order Reduction Algorithm (MORA), based on the energetic activity. By these methods, a simplified bond graph model can be obtained for a given frequency range. The stability analysis by the root locus method and the Lyapunov's second method have been examined and applied with the Bond Graph formalism support. An industrial railway traction system is considered as the case study in the application of these different analysis techniques. (author)

  14. Microfabricated tissues for investigating traction forces involved in cell migration and tissue morphogenesis.

    Science.gov (United States)

    Nerger, Bryan A; Siedlik, Michael J; Nelson, Celeste M

    2017-05-01

    Cell-generated forces drive an array of biological processes ranging from wound healing to tumor metastasis. Whereas experimental techniques such as traction force microscopy are capable of quantifying traction forces in multidimensional systems, the physical mechanisms by which these forces induce changes in tissue form remain to be elucidated. Understanding these mechanisms will ultimately require techniques that are capable of quantifying traction forces with high precision and accuracy in vivo or in systems that recapitulate in vivo conditions, such as microfabricated tissues and engineered substrata. To that end, here we review the fundamentals of traction forces, their quantification, and the use of microfabricated tissues designed to study these forces during cell migration and tissue morphogenesis. We emphasize the differences between traction forces in two- and three-dimensional systems, and highlight recently developed techniques for quantifying traction forces.

  15. Text Mining: (Asynchronous Sequences

    Directory of Open Access Journals (Sweden)

    Sheema Khan

    2014-12-01

    Full Text Available In this paper we tried to correlate text sequences those provides common topics for semantic clues. We propose a two step method for asynchronous text mining. Step one check for the common topics in the sequences and isolates these with their timestamps. Step two takes the topic and tries to give the timestamp of the text document. After multiple repetitions of step two, we could give optimum result.

  16. Asynchronous DSP-core

    OpenAIRE

    Østvand, Jon

    2007-01-01

    In this thesis multipliers with and without completion detection has been implemented using a 90 nm library to compare their properties reguarding completion time, area and power consumption. The structures tested were array and shiftand-add multipliers. The results were that when having larger bit-lengths, an asynchronous shift-and-add multiplier with completion detection can yield good completion times compared to a regular shift-and-add multiplier. Due to the large cost in area and power c...

  17. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  18. DEFINITION OF LOCOMOTIVE TRACTION FORCE WITH REGARD TO UNEVEN LOADING OF WHEEL-MOTOR BLOCK

    Directory of Open Access Journals (Sweden)

    B. Ye. Bodnar

    2013-11-01

    Full Text Available Purpose. The article describes the most common methods for determining the locomotive traction force. Solving the tasks of traction calculations involves determination of the forces influencing the train at every point of the way. When choosing a rational trajectory of the train motion and the development of operational regulations of train driving it is necessary to determine the actual value of the locomotive traction force. Considering various factors, power value of traction electric motor of locomotive may have significant differences. Advancement of the operational definition system of the locomotive traction force during the calculations by electrical parameters of traction electric motor with regard to uneven load of wheel-motor block is the purpose of the article. Methodology. The method of determining the traction force of locomotives and diesel locomotives with electric transmission, which is based on primary data acquisition of traction electric engines of direct current behavior, was proposed. Sensors and their integration into the electrical circuitry of the locomotive in order to get the data in digital form and for operational calculation of the each traction motor mode and the definition of locomotive traction force are presented. Findings. The experimental investigation of the system of locomotive traction force determination with the electric traction motor ED-105 was offered. A comparison of electrical and mechanical power of the electric motor was conducted. Originality. The system of locomotives power operational definition, which takes into account the variable electro-mechanical factors of wheel and motor blocks and increases the accuracy of the calculations, was proposed. Practical value. The system is a part of an onboard complex in definition of energy-efficient regimes for trains movement and provides the definition of accelerating and decelerating forces.

  19. ON THE TRACTION BEHAVIOR OF 4109 CHINESE AVIATION LUBRICANT

    Institute of Scientific and Technical Information of China (English)

    Ling Weiqing; Liu Gang; Xie Youbai

    2000-01-01

    Based on improved test rig with cooling system,the traction experiments for 4109 Chinese aviation lubricant are tested under various simulated working conditions.Both the experimental data thanks to their accuracy and stability and the better cooling effect of the electric shafts has given the rationality of the experimental rig a strong support.An empirical equation for calculating the traction coefficient of 4109 lubricant,which may be conveniently used for engineering application,is obtained.Furthermore,the rheological properties of the lubricant are investigated.

  20. Labeled Postings for Asynchronous Interaction

    Science.gov (United States)

    ChanLin, Lih-Juan; Chen, Yong-Ting; Chan, Kung-Chi

    2009-01-01

    The Internet promotes computer-mediated communications, and so asynchronous learning network systems permit more flexibility in time, space, and interaction than synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online…

  1. Nonlinear H-infinity feedback control for asynchronous motors of electric trains

    Science.gov (United States)

    Rigatos, Gerasimos; Siano, Pierluigi; Wira, Patrice

    2015-12-01

    A new method for feedback control of asynchronous electrical machines is introduced, with application example the problem of the traction system of electric trains. The control method consists of a repetitive solution of an H-infinity control problem for the asynchronous motor, that makes use of a locally linearized model of the motor and takes place at each iteration of the control algorithm. The asynchronous motor's model is locally linearized round its current operating point through the computation of the associated Jacobian matrices. Using the linearized model of the electrical machine an H-infinity feedback control law is computed. The known robustness features of H-infinity control enable to compensate for the errors of the approximative linearization, as well as to eliminate the effects of external perturbations. The efficiency of the proposed control scheme is shown analytically and is confirmed through simulation experiments.

  2. Wheel Slip Control for Improving Traction-Ability and Energy Efficiency of a Personal Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Kanghyun Nam

    2015-07-01

    Full Text Available In this paper, a robust wheel slip control system based on a sliding mode controller is proposed for improving traction-ability and reducing energy consumption during sudden acceleration for a personal electric vehicle. Sliding mode control techniques have been employed widely in the development of a robust wheel slip controller of conventional internal combustion engine vehicles due to their application effectiveness in nonlinear systems and robustness against model uncertainties and disturbances. A practical slip control system which takes advantage of the features of electric motors is proposed and an algorithm for vehicle velocity estimation is also introduced. The vehicle velocity estimator was designed based on rotational wheel dynamics, measurable motor torque, and wheel velocity as well as rule-based logic. The simulations and experiments were carried out using both CarSim software and an experimental electric vehicle equipped with in-wheel-motors. Through field tests, traction performance and effectiveness in terms of energy saving were all verified. Comparative experiments with variations of control variables proved the effectiveness and practicality of the proposed control design.

  3. The statics of cervical traction.

    Science.gov (United States)

    Pio, A; Rendina, M; Benazzo, F; Castelli, C; Paparella, F

    1994-08-01

    The statics of a sliding body was used to study the distribution of forces during the application of cervical traction in supine patients. This theoretical analysis was completed using a dynamometer to determine the static friction between bed surface and patient head. Therefore, we measured the head weight in 12 inpatients and the minimum force that causes impending motion of the head on the bed surface. The static friction coefficient was calculated from the ratio of the two quantities. The forces acting on the cervical spine were determined by inserting the former data into a specifically designed algorithm that forecasted a progressively increasing traction angle. The coefficient of static friction was 0.62, whereas the maximum available force acting on the cervical spine was obtained with a 35 degrees traction inclination. In contrast, the forces dissipated by the plane progressively decreased with larger angles.

  4. Compressed sensing traction force microscopy.

    Science.gov (United States)

    Brask, Jonatan Bohr; Singla-Buxarrais, Guillem; Uroz, Marina; Vincent, Romaric; Trepat, Xavier

    2015-10-01

    Adherent cells exert traction forces on their substrate, and these forces play important roles in biological functions such as mechanosensing, cell differentiation and cancer invasion. The method of choice to assess these active forces is traction force microscopy (TFM). Despite recent advances, TFM remains highly sensitive to measurement noise and exhibits limited spatial resolution. To improve the resolution and noise robustness of TFM, here we adapt techniques from compressed sensing (CS) to the reconstruction of the traction field from the substrate displacement field. CS enables the recovery of sparse signals at higher resolution from lower resolution data. Focal adhesions (FAs) of adherent cells are spatially sparse implying that traction fields are also sparse. Here we show, by simulation and by experiment, that the CS approach enables circumventing the Nyquist-Shannon sampling theorem to faithfully reconstruct the traction field at a higher resolution than that of the displacement field. This allows reaching state-of-the-art resolution using only a medium magnification objective. We also find that CS improves reconstruction quality in the presence of noise. A great scientific advance of the past decade is the recognition that physical forces determine an increasing list of biological processes. Traction force microscopy which measures the forces that cells exert on their surroundings has seen significant recent improvements, however the technique remains sensitive to measurement noise and severely limited in spatial resolution. We exploit the fact that the force fields are sparse to boost the spatial resolution and noise robustness by applying ideas from compressed sensing. The novel method allows high resolution on a larger field of view. This may in turn allow better understanding of the cell forces at the multicellular level, which are known to be important in wound healing and cancer invasion. Copyright © 2015 Acta Materialia Inc. Published by Elsevier

  5. Pro asynchronous programming with .NET

    CERN Document Server

    Blewett, Richard; Ltd, Rock Solid Knowledge

    2014-01-01

    Pro Asynchronous Programming with .NET teaches the essential skill of asynchronous programming in .NET. It answers critical questions in .NET application development, such as: how do I keep my program responding at all times to keep my users happy how do I make the most of the available hardware how can I improve performanceIn the modern world, users expect more and more from their applications and devices, and multi-core hardware has the potential to provide it. But it takes carefully crafted code to turn that potential into responsive, scalable applications.With Pro Asynchronous Programming

  6. Traction of Pneumatic Tires on Wet Runways

    Science.gov (United States)

    Horne, Walter B.; Joyner, Upshur T.

    1965-01-01

    Recent work on the traction of pneumatic tires on wet runways is discussed, and it is shown that a loss of tire traction adversely affects cross-wind landings. The effect of runway surface texture is discussed,, and a simple method for measuring surface texture is described. A preliminary correlation of tire traction with surface texture is shown. Results of work at Langley Research Center on the use of air jets to improve tire traction on wet or flooded runways indicate that this is a promising approach for alleviating the large losses in tire braking and sideways traction that occur when tire hydroplaning occurs on a flooded runway.

  7. Traction Force Measurement Using Deformable Microposts.

    Science.gov (United States)

    Xie, Tianfa; Hawkins, Jamar; Sun, Yubing

    2017-01-01

    Recent findings suggest that mechanical forces strongly influence wound repair and fibrosis across multiple organ systems. Traction force is vital to the characterization of cellular responses to mechanical stimuli. Using hydrogel-based traction force microscopy, a FRET-based tension sensor, or microengineered cantilevers, the magnitude of traction forces can be measured. Here, we describe a traction force measurement methodology using a dense array of elastomeric microposts. This platform can be used to measure the traction force of a single cell or a colony of cells with or without geometric confinement.

  8. Design on Buffer Structure of Traction Running with a Constant Speed

    Directory of Open Access Journals (Sweden)

    Zeng Xianren

    2013-06-01

    Full Text Available This study mainly aims to study buffer structure design on the traction transport system when the traction transport boundary conditions are given. With such conditions as the maximum impact force, traction speed, maximum speed of alluvium, the elasticity coefficient and the mass of buffer structure, a mathematical model was established and the solution of differential equations was solved. At last, a program was compiled with MATLAB language. With this program the elasticity coefficient and the maximum impact force which meet the requirements in impact process can be solved as long as the boundary conditions are input. This provides a quick design basis of buffer structure for most mechanical engineers.

  9. Counter traction makes endoscopic submucosal dissection easier.

    Science.gov (United States)

    Oyama, Tsuneo

    2012-11-01

    Poor counter traction and poor field of vision make endoscopic submucosal dissection (ESD) difficult. Good counter traction allows dissections to be performed more quickly and safely. Position change, which utilizes gravity, is the simplest method to create a clear field of vision. It is useful especially for esophageal and colon ESD. The second easiest method is clip with line method. Counter traction made by clip with line accomplishes the creation of a clear field of vision and suitable counter traction thereby making ESD more efficient and safe. The author published this method in 2002. The name ESD was not established in those days; the name cutting endoscopic mucosal resection (EMR) or EMR with hook knife was used. The other traction methods such as external grasping forceps, internal traction, double channel scope, and double scopes method are introduced in this paper. A good strategy for creating counter traction makes ESD easier.

  10. PERFORMANCE SIMULATION OF VEHICLES EQUIPPED WITH TRACTION DRIVE CVTS

    Institute of Scientific and Technical Information of China (English)

    Zhang Xianjie; William E.Tobler; Zhang Yi; Zou Zhanjiang

    2005-01-01

    A computer model for the performance simulation of vehicles equipped with traction drive continuously variable transmission (CVT) is presented. The model integrates the traction drive CVT subsystem into an existing overall vehicle system. The characteristics of engine output torque are formulated using neural networks, and torque converter is modeled using lookup tables. Component inputs and outputs are coupled in the dynamic equations and interfaces in the powertrain system. The model simulation can provide evaluation of vehicle performance in drivability, fuel economy and emission levels for various drive ranges prior to the prototyping of the vehicle. As a design tool, the model assists engineers in understanding the effect of powertrain components on vehicle performance and making decisions in the selection of key design parameters. The model is implemented in the MATLAB/Simulink environment. The performance simulation of a test vehicle is included as a numerical example to illustrate the effectiveness of the model.

  11. THE INFLUENCE OF POWER STATOR WINDINGS OF THE ASYNCHRONOUS TRACTION MOTORS FOR DYNAMIC WORKLOAD ELEMENTS OF TRACTION DRIVE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    O. M. Bondarev

    2010-01-01

    Full Text Available The results of studies on determination of loading level of tractive drive elements in some operating conditions, when the values of frequencies of the change of feeding currents of stator windings are to be obtained in both subcritical and ultracritical zones for two types of the tractive gear are presented in the paper.

  12. Creation of electromechanical device for electric vehicle traction

    Directory of Open Access Journals (Sweden)

    Денис Юрьевич Зубенко

    2016-10-01

    Full Text Available The problems of creation of electromechanical device for electric vehicle traction are considered in the article. The aim of creation this design are the replacement of the internal combustion engine on electromechanical device. For this electromechanical device are constructed model, which describe processes that occur in the electric drive of electromechanical device. Characteristics of the main modes of motion were recorded. The introduction of electromechanical device will reduce the level of emissions and reduce noise in the cities

  13. Asynchronous parallel pattern search for nonlinear optimization

    Energy Technology Data Exchange (ETDEWEB)

    P. D. Hough; T. G. Kolda; V. J. Torczon

    2000-01-01

    Parallel pattern search (PPS) can be quite useful for engineering optimization problems characterized by a small number of variables (say 10--50) and by expensive objective function evaluations such as complex simulations that take from minutes to hours to run. However, PPS, which was originally designed for execution on homogeneous and tightly-coupled parallel machine, is not well suited to the more heterogeneous, loosely-coupled, and even fault-prone parallel systems available today. Specifically, PPS is hindered by synchronization penalties and cannot recover in the event of a failure. The authors introduce a new asynchronous and fault tolerant parallel pattern search (AAPS) method and demonstrate its effectiveness on both simple test problems as well as some engineering optimization problems

  14. Efficacy of home cervical traction therapy.

    Science.gov (United States)

    Swezey, R L; Swezey, A M; Warner, K

    1999-01-01

    Cervical traction is administered by various techniques ranging from supine mechanical motorized cervical traction to seated cervical traction using an over-the-door pulley support with attached weights. Duration of cervical traction can range from a few minutes to 20 to 30 min, once or twice weekly to several times per day. Anecdotal evidence suggests efficacy and safety, but there is no documentation of efficacy of cervical traction beyond short-term pain reduction. Because of a clinical impression that a simplified, inexpensive, over-the-door home cervical traction method of treatment requiring 5 min of cervical traction twice daily was efficacious for both cervical pain and radiculopathic syndromes, we undertook a retrospective study of 58 outpatients treated between 1994 and 1996. Age range was 29 to 84 (mean, 56) yr. Twenty-three males and 35 females were classified as Grade 1 to Grade 3 according to the Quebec Task Force of Whiplash-Associated Disorders Cohort Study. Outcomes were as follows: Grade 1 (mild)--4 of 4 (100%) patients improved; Grade 2 (moderate)--34 of 44 (77%) patients improved (P cervical traction; Grade 3 (patients with radiculopathy)--9 of 10 (90%) patients improved (P cervical traction modality provided symptomatic relief in 81% of the patients with mild to moderately severe (Grade 3) cervical spondylosis syndromes. Prospective, randomized assessment of cervical traction for this and other methods is needed.

  15. Plica neuropathica causing traction alopecia

    Directory of Open Access Journals (Sweden)

    Pavithran K

    1990-01-01

    Full Text Available A middle aged woman developed matting of the hairs of the scalp following use of a home made shampoo that contained leaves of Hibiscus rosasiensis. The entangled and matted hair mass in the occipital region pulled hairs of the vertex region of the scalp, resulting in a patch of traction alopecia. Release of tension on the hairs by cutting them with scissors prevented further extension of alopecia.

  16. Asynchronous Bounded Expected Delay Networks

    CERN Document Server

    Bakhshi, Rena; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).

  17. Effects of cervical traction on muscle activity.

    Science.gov (United States)

    Murphy, M J

    1991-01-01

    The effect of cervical traction on the musculature of patients with complaints of neck pain has not been thoroughly researched. Lateral neck muscles were selected for study because they receive their innervation from the lower cervical region, where traction has been documented by radiography to have its greatest mechanical effects. Six subjects with complaints of neck pain, limited range of motion, and a positive quadrant test were compared to six normal subjects. Surface electromyography (EMG) of the lateral neck musculature was recorded before, during, and after supine intermittent mechanical traction. No significant difference between groups (p > .05) was noted in EMG recordings at rest and within 10 minutes of traction. Subjective relief was noted up to 12 hours after traction in pain subjects. Cervical traction does not appear to produce immediate muscular relaxation as measured with EMG equipment. J Orthop Sports Phys Ther 1991;13(5):220-225.

  18. Selective particle capture by asynchronously beating cilia

    Science.gov (United States)

    Ding, Yang; Kanso, Eva

    2015-12-01

    Selective particle filtration is fundamental in many engineering and biological systems. For example, many aquatic microorganisms use filter feeding to capture food particles from the surrounding fluid, using motile cilia. One of the capture strategies is to use the same cilia to generate feeding currents and to intercept particles when the particles are on the downstream side of the cilia. Here, we develop a 3D computational model of ciliary bands interacting with flow suspended particles and calculate particle trajectories for a range of particle sizes. Consistent with experimental observations, we find optimal particle sizes that maximize capture rate. The optimal size depends nonlinearly on cilia spacing and cilia coordination, synchronous vs. asynchronous. These parameters affect the cilia-generated flow field, which in turn affects particle trajectories. The low capture rate of smaller particles is due to the particles' inability to cross the flow streamlines of neighboring cilia. Meanwhile, large particles have difficulty entering the sub-ciliary region once advected downstream, also resulting in low capture rates. The optimal range of particle sizes is enhanced when cilia beat asynchronously. These findings have potentially important implications on the design and use of biomimetic cilia in processes such as particle sorting in microfluidic devices.

  19. UNIVERSAL REGULAR AUTONOMOUS ASYNCHRONOUS SYSTEMS: ω-LIMIT SETS, INVARIANCE AND BASINS OF ATTRACTION

    Directory of Open Access Journals (Sweden)

    Serban Vlad

    2011-07-01

    Full Text Available The asynchronous systems are the non-deterministic real timebinarymodels of the asynchronous circuits from electrical engineering.Autonomy means that the circuits and their models have no input.Regularity means analogies with the dynamical systems, thus such systems may be considered to be real time dynamical systems with a’vector field’, Universality refers to the case when the state space of the system is the greatest possible in the sense of theinclusion. The purpose of this paper is that of defining, by analogy with the dynamical systems theory, the omega-limit sets, the invariance and the basins of attraction of the universal regular autonomous asynchronous systems.

  20. Acquiring Knowledge from Asynchronous Discussion

    Science.gov (United States)

    Teo, Yiong Hwee; Webster, Len

    2008-01-01

    This article discusses a study which was designed to explore how online scaffolding can be incorporated to support knowledge acquisition in asynchronous discussion. A group of Singapore preservice teachers engaged in collaborative critiquing of videos before they embarked on their video projects to illustrate what constitutes good and bad video…

  1. Asymptotic behavior of asynchronous stochasticapproximation

    Institute of Scientific and Technical Information of China (English)

    方海涛; 陈翰馥

    2001-01-01

    The pathwise convergence of a distributed, asynchronous stochastic approximation (SA) scheme is analyzed. The conditions imposed on the step size and noise are the weakest in comparison with the existing ones. The step sizes in different processors are allowed to be different, and the time_delays between processors are also allowed to be different and even time_varying.

  2. Asynchronous sequential machine design and analysis

    CERN Document Server

    Tinder, Richard

    2009-01-01

    Asynchronous Sequential Machine Design and Analysis provides a lucid, in-depth treatment of asynchronous state machine design and analysis presented in two parts: Part I on the background fundamentals related to asynchronous sequential logic circuits generally, and Part II on self-timed systems, high-performance asynchronous programmable sequencers, and arbiters.Part I provides a detailed review of the background fundamentals for the design and analysis of asynchronous finite state machines (FSMs). Included are the basic models, use of fully documented state diagrams, and the design and charac

  3. Traction Control System for Motorcycles

    Directory of Open Access Journals (Sweden)

    Cardinale Pascal

    2009-01-01

    Full Text Available Traction control is a widely used control system to increase stability and safety of four wheel vehicles. Automatic stability control is used in the BMW K1200R motorcycle and in motoGP competition, but not in other motorcycles. This paper presents an algorithm and a low-cost real-time hardware implementation for motorcycles. A prototype has been developed, applied on a commercial motorcycle, and tested in a real track. The control system that can be tuned by the driver during the race has been appreciated by the test driver.

  4. Traction Control System for Motorcycles

    Directory of Open Access Journals (Sweden)

    Massimo Conti

    2009-01-01

    Full Text Available Traction control is a widely used control system to increase stability and safety of four wheel vehicles. Automatic stability control is used in the BMW K1200R motorcycle and in motoGP competition, but not in other motorcycles. This paper presents an algorithm and a low-cost real-time hardware implementation for motorcycles. A prototype has been developed, applied on a commercial motorcycle, and tested in a real track. The control system that can be tuned by the driver during the race has been appreciated by the test driver.

  5. Elastohydrodynamic Traction Properties of Seed Oils

    Science.gov (United States)

    The elastohydrodynamic traction coefficient (tc) properties of nine seed oils of varying chemical structures, PAO and hexadecane, were investigated using a ball-on disk traction apparatus. The seed oils were: castor oil, a triglyceride with hydroxyl functional group; jojoba, a monoglyceride; and s...

  6. Elastohydrodynamic (EHD) traction properties of seed oils

    Science.gov (United States)

    The elastohydrodynamic traction coefficient (tc) properties of nine seed oils of varying chemical structures, PAO and hexadecane, were investigated using a ball-on disk traction apparatus. The seed oils were: castor oil, a triglyceride with hydroxyl functional group; jojoba, a monoglyceride; and sev...

  7. Asynchronous control for networked systems

    CERN Document Server

    Rubio, Francisco; Bencomo, Sebastián

    2015-01-01

    This book sheds light on networked control systems; it describes different techniques for asynchronous control, moving away from the periodic actions of classical control, replacing them with state-based decisions and reducing the frequency with which communication between subsystems is required. The text focuses specially on event-based control. Split into two parts, Asynchronous Control for Networked Systems begins by addressing the problems of single-loop networked control systems, laying out various solutions which include two alternative model-based control schemes (anticipatory and predictive) and the use of H2/H∞ robust control to deal with network delays and packet losses. Results on self-triggering and send-on-delta sampling are presented to reduce the need for feedback in the loop. In Part II, the authors present solutions for distributed estimation and control. They deal first with reliable networks and then extend their results to scenarios in which delays and packet losses may occur. The novel ...

  8. Queue-Dispatch Asynchronous Systems

    CERN Document Server

    Geeraerts, Gilles; Raskin, Jean-François

    2012-01-01

    To make the development of efficient multi-core applications easier, libraries, such as Grand Central Dispatch, have been proposed. When using such a library, the programmer writes so-called blocks, which are chunks of codes, and dispatches them, using synchronous or asynchronous calls, to several types of waiting queues. A scheduler is then responsible for dispatching those blocks on the available cores. Blocks can synchronize via a global memory. In this paper, we propose Queue-Dispatch Asynchronous Systems as a mathematical model that faithfully formalizes the synchronization mechanisms and the behavior of the scheduler in those systems. We study in detail their relationships to classical formalisms such as pushdown systems, Petri nets, fifo systems, and counter systems. Our main technical contributions are precise worst-case complexity results for the Parikh coverability problem for several subclasses of our model.

  9. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    domain by introducing a computation model, which resembles the synchronous datapath and control architecture, but which is completely asynchronous. The model contains the possibility for isolating some or all of the functional units by locking their respective inputs and outputs while the functional unit....... The datapath and control architecture is then expressed in the Balsa-language, and using syntax directed compilation a corresponding handshake circuit implementation (and eventually a layout) is produced....

  10. GAMIFICATION IN ASYNCHRONOUS EDUCATION PROCESS

    Directory of Open Access Journals (Sweden)

    B. P. Dyakonov

    2016-01-01

    Full Text Available The author of the paper discourses on the prospects of education in the context of the global tendency towards informatization and virtualization of the modern world, influence of these processes on personalized senses of education and educational values and related problems of methodological and technological education in relation to the personalized meanings and educational values. Educational individualization is defined by the author as the most expected way of educational evolution. Distance learning is studied as the main example of the modern transformative educational model. Asynchronous education is explored and characterized as one of the distance learning examples. While defining what asynchronous distance learning is, the author explores its role in the specifics of forming a subject to subject educational approach, while forecasting difficulties in creating holistic asynchronous educational environment. Gamification techniques in the educational process are studied with their respective opportunities and threats, examples in grad and post grad professional studies are provided, including but not limited to foreign language studies. Addictiveness as the goal and means of a build in gamification process is explored as the way to bridge the gap between students and the educators. The author studies gamification in the context of minimizing negative connotations from the educational process, while controversies between pain and game approaches of getting knowledge are brought into light.

  11. A massively asynchronous, parallel brain

    Science.gov (United States)

    Zeki, Semir

    2015-01-01

    Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously—with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain. PMID:25823871

  12. Liposome adhesion generates traction stress

    Science.gov (United States)

    Murrell, Michael P.; Voituriez, Raphaël; Joanny, Jean-François; Nassoy, Pierre; Sykes, Cécile; Gardel, Margaret L.

    2014-02-01

    Mechanical forces generated by cells modulate global shape changes required for essential life processes, such as polarization, division and spreading. Although the contribution of the cytoskeleton to cellular force generation is widely recognized, the role of the membrane is considered to be restricted to passively transmitting forces. Therefore, the mechanisms by which the membrane can directly contribute to cell tension are overlooked and poorly understood. To address this, we directly measure the stresses generated during liposome adhesion. We find that liposome spreading generates large traction stresses on compliant substrates. These stresses can be understood as the equilibration of internal, hydrostatic pressures generated by the enhanced membrane tension built up during adhesion. These results underscore the role of membranes in the generation of mechanical stresses on cellular length scales and that the modulation of hydrostatic pressure due to membrane tension and adhesion can be channelled to perform mechanical work on the environment.

  13. 浅谈轨道牵引机车与城轨车辆车体腻子涂刮技艺%A Brief Talk on Putty Coating and Scraping Techniques of Railway Traction Engine and Urban Rail Vehicle Body

    Institute of Scientific and Technical Information of China (English)

    苏权; 张煜

    2012-01-01

    This paper mainly elaborates putty coating and scraping technique of railway traction engine and urban rail vehicle body, and the techniques and methods of putty selection, ash-mixing amount, cutting and scraping tools and methods, putty polishing as well as quality inspection of vehicle body outside were introduced in detail.%本文主要阐述了轨道牵引机车与城轨车辆车体的腻子涂刮技艺,结合操作实践,重点介绍了车体外墙腻子选型、和灰量、涂刮工具、涂刮方法、腻子打磨及质量检验等施工方面的技巧和方法。

  14. Modern Electric Traction of Skoda Plzen Vehicles Modern Electric Traction of Skoda Plzen Vehicles

    Directory of Open Access Journals (Sweden)

    Jiri Drabek

    2005-01-01

    Full Text Available The electric traction vehicle producting plant SKODA Plzen - Transportations develops and produces electric traction drives with the top technological niveau. Electric vehicles are delivered to transport institutions in Czech Republic as well as abroad. Many Ma, and PhD. graduates of the University of Zilina take part in this successful activity.The electric traction vehicle producting plant SKODA Plzen - Transportations develops and produces electric traction drives with the top technological niveau. Electric vehicles are delivered to transport institutions in Czech Republic as well as abroad. Many Ma, and PhD. graduates of the University of Zilina take part in this successful activity.

  15. [Traction maculopathies--pathogenesis and diagnostics].

    Science.gov (United States)

    Wylegała, Edward; Woyna-Orlewicz, Anna; Piłat, Jarosław; Teper, Sławomir; Ludyga, Aneta

    2006-01-01

    Traction maculopathies are a group of age-related degenerative diseases characterized by pathology of vitreomacular interface including idiopathic epimacular membranes, vitreomacular traction syndrome and idiopathic macular hole. The disorders develop due to mechanical forces caused by focal condensation or incomplete detachement of vitreous and shrinkage of pathological membranes. The forces can be tangential to retinal surface in epiretinal membranes, anterior-posterior in vitreomacular traction syndrome and oblique (trampoline) in idiopathic macular hole. Authors discuss pathogenesis and diagnostics of traction maculopathies with use of optical coherence tomography and microperimetry, based on current literature. This work presents also idiopathic macular hole classification with use of optical coherence tomography images compared with biomicroscopic classification by Gass.

  16. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  17. Realization of station for testing asynchronous three-phase motors

    Science.gov (United States)

    Wróbel, A.; Surma, W.

    2016-08-01

    Nowadays, you cannot imagine the construction and operation of machines without the use of electric motors [13-15]. The proposed position is designed to allow testing of asynchronous three-phase motors. The position consists of a tested engine and the engine running as a load, both engines combined with a mechanical clutch [2]. The value of the load is recorded by measuring shaft created with Strain Gauge Bridge. This concept will allow to study the basic parameters of the engines, visualization motor parameters both vector and scalar controlled, during varying load drive system. In addition, registration during the variable physical parameters of the working electric motor, controlled by a frequency converter or controlled by a contactor will be possible. Position is designed as a teaching and research position to characterize the engines. It will be also possible selection of inverter parameters.

  18. 3D Viscoelastic traction force microscopy.

    Science.gov (United States)

    Toyjanova, Jennet; Hannen, Erin; Bar-Kochba, Eyal; Darling, Eric M; Henann, David L; Franck, Christian

    2014-10-28

    Native cell-material interactions occur on materials differing in their structural composition, chemistry, and physical compliance. While the last two decades have shown the importance of traction forces during cell-material interactions, they have been almost exclusively presented on purely elastic in vitro materials. Yet, most bodily tissue materials exhibit some level of viscoelasticity, which could play an important role in how cells sense and transduce tractions. To expand the realm of cell traction measurements and to encompass all materials from elastic to viscoelastic, this paper presents a general, and comprehensive approach for quantifying 3D cell tractions in viscoelastic materials. This methodology includes the experimental characterization of the time-dependent material properties for any viscoelastic material with the subsequent mathematical implementation of the determined material model into a 3D traction force microscopy (3D TFM) framework. Utilizing this new 3D viscoelastic TFM (3D VTFM) approach, we quantify the influence of viscosity on the overall material traction calculations and quantify the error associated with omitting time-dependent material effects, as is the case for all other TFM formulations. We anticipate that the 3D VTFM technique will open up new avenues of cell-material investigations on even more physiologically relevant time-dependent materials including collagen and fibrin gels.

  19. Asynchronous Learning Forums for Business Acculturation

    Science.gov (United States)

    Pence, Christine Cope; Wulf, Catharina

    2009-01-01

    The use of IT as a facilitator for student collaboration in higher business education has grown rapidly since 2000. Asynchronous discussion forums are used abundantly for collaborative training purposes and for teaching students business-relevant tools for their future careers. This article presents an analysis of the asynchronous discussion forum…

  20. Road dust from pavement wear and traction sanding

    Energy Technology Data Exchange (ETDEWEB)

    Kupiainen, K.

    2007-07-01

    Vehicles affect the concentrations of ambient airborne particles through exhaust emissions, but particles are also formed in the mechanical processes in the tire-road interface, brakes, and engine. Particles deposited on or in the vicinity of the road may be re-entrained, or resuspended, into air through vehicle-induced turbulence and shearing stress of the tires. A commonly used term for these particles is 'road dust'. The processes affecting road dust emissions are complex and currently not well known. Road dust has been acknowledged as a dominant source of PM10 especially during spring in the sub-arctic urban areas, e.g. in Scandinavia, Finland, North America and Japan. The high proportion of road dust in sub-arctic regions of the world has been linked to the snowy winter conditions that make it necessary to use traction control methods. Traction control methods include dispersion of traction sand, melting of ice with brine solutions, and equipping the tires with either metal studs (studded winter tires), snow chains, or special tire design (friction tires). Several of these methods enhance the formation of mineral particles from pavement wear and/or from traction sand that accumulate in the road environment during winter. When snow and ice melt and surfaces dry out, traffic-induced turbulence makes some of the particles airborne. A general aim of this study was to study processes and factors underlying and affecting the formation and emissions of road dust from paved road surfaces. Special emphasis was placed on studying particle formation and sources during tire road interaction, especially when different applications of traction control, namely traction sanding and/or winter tires were in use. Respirable particles with aerodynamic diameter below 10 micrometers (PM10) have been the main concern, but other size ranges and particle size distributions were also studied. The following specific research questions were addressed: (i) How do traction

  1. Asynchronous Parallelization of a CFD Solver

    Directory of Open Access Journals (Sweden)

    Daniel S. Abdi

    2015-01-01

    Full Text Available A Navier-Stokes equations solver is parallelized to run on a cluster of computers using the domain decomposition method. Two approaches of communication and computation are investigated, namely, synchronous and asynchronous methods. Asynchronous communication between subdomains is not commonly used in CFD codes; however, it has a potential to alleviate scaling bottlenecks incurred due to processors having to wait for each other at designated synchronization points. A common way to avoid this idle time is to overlap asynchronous communication with computation. For this to work, however, there must be something useful and independent a processor can do while waiting for messages to arrive. We investigate an alternative approach of computation, namely, conducting asynchronous iterations to improve local subdomain solution while communication is in progress. An in-house CFD code is parallelized using message passing interface (MPI, and scalability tests are conducted that suggest asynchronous iterations are a viable way of parallelizing CFD code.

  2. Changes in joint space width during Kaltenborn traction according to traction grade in healthy adults.

    Science.gov (United States)

    Moon, Gui-do; Kim, Tae-Ho; Lim, Jin-Yong

    2016-01-01

    [Purpose] The aim of this study was to analyze the joint space width of the humeral head and glenoid fossa during traction under 2 grade conditions (grade 2/grade 3). [Subjects and Methods] The subjects were 20 healthy male adults who had not experienced any shoulder injury. Three radiographs were obtained with the subjects in the supine position (resting, grades 2 and 3). The glenohumeral joint space was examined on radiography. Joint space width was measured by a radiologist at the points described by Petersson and Redlund-Johnell. A radiologist blinded to the variable "resting" or "traction" performed all radiographic measurements. The joint space widths were compared by using one-way repeated-measures analysis of variance. [Results] The results of this study indicated significant differences in the changes in joint space width according to traction grade. Compared to resting, grades 2 and 3 traction significantly increased joint space width. However, no significant difference in joint space width was found between grades 2 and 3 traction. [Conclusion] Although no significant differences were found between grades 2 and 3 traction during glenohumeral joint traction, the increase in joint space width between the glenoid fossa and humeral head was highest during grade 3 traction.

  3. The traction angle and cervical intervertebral separation.

    Science.gov (United States)

    Wong, A M; Leong, C P; Chen, C M

    1992-02-01

    Seventeen normal young adults were evaluated for cervical intervertebral separation under different traction angles through motorized intermittent traction in the supine position. In all cases, the anterior and posterior intervertebral spaces were increased by traction at neutral position and in 30 degrees flexion, but not in 15 degrees extension. The effects of separation were 1) neutral position: anterior intervertebral separation C4-5 (12%) greater than C3-4 (8%), posterior intervertebral separation C6-7 (37%) greater than C3-4 (22%) greater than C4-5 (19%); and 2) 30 degrees flexion: anterior intervertebral separation C2-3 (21%) greater than C4-5 (16%) greater than C5-6 (15%) greater than C3-4 (10%), posterior intervertebral separation C6-7 (20%) greater than C5-6 (19%) greater than C4-5 (17%). There was a significant decrease in intervertebral separation posteriorly in extension traction, especially at C6-7 (-50%), C5-6 (-37%), C4-5 (-26%), and C3-4 (-14%). The separation of facet joint surfaces was found after traction at 15 degrees extension, but not in the neutral or flexion positions.

  4. Asynchronous Capacity per Unit Cost

    CERN Document Server

    Chandar, Venkat; Tse, David

    2010-01-01

    The capacity per unit cost, or equivalently minimum cost to transmit one bit, is a well-studied quantity. It has been studied under the assumption of full synchrony between the transmitter and the receiver. In many applications, such as sensor networks, transmissions are very bursty, with small amounts of bits arriving infrequently at random times. In such scenarios, the cost of acquiring synchronization is significant and one is interested in the fundamental limits on communication without assuming a priori synchronization. In this paper, we show that the minimum cost to transmit B bits of information asynchronously is (B + \\bar{H})k_sync, where k_sync is the synchronous minimum cost per bit and \\bar{H} is a measure of timing uncertainty equal to the entropy for most reasonable arrival time distributions.

  5. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

  6. Self arbitrated VLSI asynchronous sequential circuits

    Science.gov (United States)

    Whitaker, S.; Maki, G.

    1990-01-01

    A new class of asynchronous sequential circuits is introduced in this paper. The new design procedures are oriented towards producing asynchronous sequential circuits that are implemented with CMOS VLSI and take advantage of pass transistor technology. The first design algorithm utilizes a standard Single Transition Time (STT) state assignment. The second method introduces a new class of self synchronizing asynchronous circuits which eliminates the need for critical race free state assignments. These circuits arbitrate the transition path action by forcing the circuit to sequence through proper unstable states. These methods result in near minimum hardware since only the transition paths associated with state variable changes need to be implemented with pass transistor networks.

  7. Modeling traction forces in collective cell migration

    Science.gov (United States)

    Zimmermann, Juliane; Basan, Markus; Hayes, Ryan L.; Rappel, Wouter-Jan; Levine, Herbert

    2015-03-01

    Collective cell migration is an important process in embryonic development, wound healing, and cancer metastasis. We have developed a particle-based simulation for collective cell migration that describes flow patterns and finger formation at the tissue edge observed in wound healing experiments. We can apply methods for calculating intercellular stress to our simulation model, and have thereby provided evidence for the validity of a stress reconstitution method from traction forces used in experiments. To accurately capture experimentally measured traction forces and stresses in the tissue, which are mostly tensile, we have to include intracellular acto-myosin contraction into our simulation. We can then reproduce the experimentally observed behavior of cells moving around a circular obstacle, and suggest underlying mechanisms for cell-cell alignment and generation of traction force patterns.

  8. Posterior lip traction caused by intravitreal gas

    Energy Technology Data Exchange (ETDEWEB)

    Lincoff, H.; Kreissig, I.

    1981-08-01

    Traction on the posterior edge of a large tear may be an irreparable consequence of an intraocular gas tamponade used in the first instance to treat the tear. In two of three patients treated with octofluorocyclobutane (C4F8) and perfluoromethane (CF4), redetachment of a retinal tear occurred as a result of traction on the posterior edge of the tear when, prior to the operation, the posterior edge seemed to be free of any traction. With redetachment, a membrane became visible between the anterior and posterior lips of the tear. The membrane was probably posterior hyaloid augmented by cellular proliferation. The gas bubble, which had been intended to press the retina against the pigment epithelium, probably brought the detached posterior hyaloid into contact with the retina as well, and an adhesion between the hyaloid and retina formed.

  9. 3D Neutrophil Tractions in Changing Microenvironments

    Science.gov (United States)

    Toyjanova, Jennet; Flores, Estefany; Reichner, Jonathan; Franck, Christian

    2012-02-01

    Neutrophils are well-known as first responders to defend the body against life threatening bacterial diseases, infections and inflammation. The mechanical properties and the local topography of the surrounding microenvironment play a significant role in the regulating neutrophil behavior including cell adhesion, migration and generation of tractions. In navigating to the site of infection, neutrophils are exposed to changing microenvironments that differ in their composition, structure and mechanical properties. Our goal is to investigate neutrophil behavior, specifically migration and cellular tractions in a well-controlled 3D in vitro system. By utilizing an interchangeable 2D-3D sandwich gel structure system with tunable mechanical properties neutrophil migration and cell tractions can be computed as a function of gel stiffness and geometric dimensionality.

  10. Asynchronous stochastic approximation with differential inclusions

    Directory of Open Access Journals (Sweden)

    David S. Leslie

    2012-01-01

    Full Text Available The asymptotic pseudo-trajectory approach to stochastic approximation of Benaïm, Hofbauer and Sorin is extended for asynchronous stochastic approximations with a set-valued mean field. The asynchronicity of the process is incorporated into the mean field to produce convergence results which remain similar to those of an equivalent synchronous process. In addition, this allows many of the restrictive assumptions previously associated with asynchronous stochastic approximation to be removed. The framework is extended for a coupled asynchronous stochastic approximation process with set-valued mean fields. Two-timescales arguments are used here in a similar manner to the original work in this area by Borkar. The applicability of this approach is demonstrated through learning in a Markov decision process.

  11. Electric traction motion power and energy supply : basics and practical experience

    CERN Document Server

    Steimel, Andreas

    2011-01-01

    This book has evolved from the lecture series ""Elektrische Bahnen" (""Electric railways") which has been held at Ruhr-Universität Bochum since 1996. Its primary audience are students of electrical energy technologies, control engineering and mechanical engineering as well as young engineers of electrical engineering, especially in the fields of power electronics, in railway industry and in railway-operating companies. The book intends to convey mechanical fundamentals of electric railway propulsion, which includes rail-bound guidance, transmission of traction effort from wheel to rail under t

  12. Facial nerve paralysis after cervical traction.

    Science.gov (United States)

    So, Edmund Cheung

    2010-10-01

    Cervical traction is a frequently used treatment in rehabilitation clinics for cervical spine problems. This modality works, in principle, by decompressing the spinal cord or its nerve roots by applying traction on the cervical spine through a harness placed over the mandible (Olivero et al., Neurosurg Focus 2002;12:ECP1). Previous reports on treatment complications include lumbar radicular discomfort, muscle injury, neck soreness, and posttraction pain (LaBan et al., Arch Phys Med Rehabil 1992;73:295-6; Lee et al., J Biomech Eng 1996;118:597-600). Here, we report the first case of unilateral facial nerve paralysis developed after 4 wks of intermittent cervical traction therapy. Nerve conduction velocity examination revealed a peripheral-type facial nerve paralysis. Symptoms of facial nerve paralysis subsided after prednisolone treatment and suspension of traction therapy. It is suspected that a misplaced or an overstrained harness may have been the cause of facial nerve paralysis in this patient. Possible causes were (1) direct compression by the harness on the right facial nerve near its exit through the stylomastoid foramen; (2) compression of the right external carotid artery by the harness, causing transient ischemic injury at the geniculate ganglion; or (3) coincidental herpes zoster virus infection or idiopathic Bell's palsy involving the facial nerve.

  13. Implementation of Fleet Management in Train Traction

    Directory of Open Access Journals (Sweden)

    Tomislav Josip Mlinarić

    2008-05-01

    Full Text Available The implementation of fleet management in the train tractionactivity is a must in the conditions of market operation ofthe railway sector, since good management of traction units hasnot alternative. The crucial issue of implementing such sophisticatedtools is in real environment, and therefore SWOT analysisof the most important technological indicators has been carriedout, in order to determine the most efficient method of itsimplementation. The defined technological indicators and therespective criteria have been used to evaluate the possible implementationof the total fleet management system in the HiVuca vlakova (Hi- Train Traction company. The pilot projectcarried out in the activities of the Hi- Train Traction hasresulted in great savings at the annual level in fuel consumption,creating also the preconditions for the savings in fleetmaintenance and work force recruitment. Based on the resultsof the pilot project the methodology for efficient implementationof fleet management was defined. The defined methodologywas tested in real conditions and can be implemented atany company which provides services of train traction or manoeuvringof locomotives.

  14. Prediction of traction forces of motile cells

    Science.gov (United States)

    Roux, Clément; Laurent, Valérie M.; Michel, Richard; Peschetola, Valentina

    2016-01-01

    When crawling on a flat substrate, living cells exert forces on it via adhesive contacts, enabling them to build up tension within their cytoskeleton and to change shape. The measurement of these forces has been made possible by traction force microscopy (TFM), a technique which has allowed us to obtain time-resolved traction force maps during cell migration. This cell ‘footprint’ is, however, not sufficient to understand the details of the mechanics of migration, that is how cytoskeletal elements (respectively, adhesion complexes) are put under tension and reinforce or deform (respectively, mature and/or unbind) as a result. In a recent paper, we have validated a rheological model of actomyosin linking tension, deformation and myosin activity. Here, we complement this model with tentative models of the mechanics of adhesion and explore how closely these models can predict the traction forces that we recover from experimental measurements during cell migration. The resulting mathematical problem is a PDE set on the experimentally observed domain, which we solve using a finite-element approach. The four parameters of the model can then be adjusted by comparison with experimental results on a single frame of an experiment, and then used to test the predictive power of the model for following frames and other experiments. It is found that the basic pattern of traction forces is robustly predicted by the model and fixed parameters as a function of current geometry only. PMID:27708765

  15. Universal regular autonomous asynchronous systems: omega-limit sets, invariance and basins of attraction

    CERN Document Server

    Vlad, Serban E

    2010-01-01

    The asynchronous systems are the non-deterministic real time-binary models of the asynchronous circuits from electrical engineering. Autonomy means that the circuits and their models have no input. Regularity means analogies with the dynamical systems, thus such systems may be considered to be the real time dynamical systems with a 'vector field' {\\Phi}:{0,1}^2 \\rightarrow {0,1}^2. Universality refers to the case when the state space of the system is the greatest possible in the sense of the inclusion. The purpose of the paper is that of defining, by analogy with the dynamical systems theory, the {\\omega}-limit sets, the invariance and the basins of attraction of the universal regular autonomous asynchronous systems.

  16. Micropatterning tractional forces in living cells

    Science.gov (United States)

    Wang, Ning; Ostuni, Emanuele; Whitesides, George M.; Ingber, Donald E.

    2002-01-01

    Here we describe a method for quantifying traction in cells that are physically constrained within micron-sized adhesive islands of defined shape and size on the surface of flexible polyacrylamide gels that contain fluorescent microbeads (0.2-microm diameter). Smooth muscle cells were plated onto square (50 x 50 microm) or circular (25- or 50-microm diameter) adhesive islands that were created on the surface of the gels by applying a collagen coating through microengineered holes in an elastomeric membrane that was later removed. Adherent cells spread to take on the size and shape of the islands and cell tractions were quantitated by mapping displacement fields of the fluorescent microbeads within the gel. Cells on round islands did not exhibit any preferential direction of force application, but they exerted their strongest traction at sites where they formed protrusions. When cells were confined to squares, traction was highest in the corners both in the absence and presence of the contractile agonist, histamine, and cell protrusions were also observed in these regions. Quantitation of the mean traction exerted by cells cultured on the different islands revealed that cell tension increased as cell spreading was promoted. These results provide a mechanical basis for past studies that demonstrated a similar correlation between spreading and growth within various anchorage-dependent cells. This new approach for analyzing the spatial distribution of mechanical forces beneath individual cells that are experimentally constrained to defined sizes and shapes may provide additional insight into the biophysical basis of cell regulation. Copyright 2002 Wiley-Liss, Inc.

  17. THEORETICAL ASPECTS AND METHODS OF PARAMETERS IDENTIFICATION OF ELECTRIC TRACTION SYSTEM DEVICES. METHOD OF WEIGHT FUNCTION

    Directory of Open Access Journals (Sweden)

    T. N. Mishchenko

    2014-10-01

    Full Text Available Purpose. Development and substantiation of a new method of structural identification of electrical devices of electric traction systems for both DC and AC current. Methodology. To solve this problem the following methods are used: the methods and techniques of the linear electrical engineering, in particular, the Laplace operator method; the numerical method for solving the integral equation, which is based on the representation of the Wiener-Hopf linear equations system (this allows forming the solutions of the problem in a mathematical form of the correlation and weight functions; the factorization method, which provides certain partition of the correlation functions of the stochastic processes. Findings. It was developed the method of weight function of the electrical devices identification, which can be fully used in the systems of electric traction. As the use example of the developed method it was considered a feeder section of DC electric traction with the single power supply. On this section move two electric locomotives of the type DE 1, they have been identified by the weighting functions. The required currents and voltages of electric locomotives are also formulated in the electric traction network in probabilistic and statistical form, that is, the functions of mathematical expectation and the correlation functions are determined. At this, it is taken into account that the correlation function of the sum of random functions is equal to the sum of the correlation functions of additives, and the correlation function of the integral of a random function is defined as the double integral of the correlation function of the output of a random function. Originality. Firstly, originality consists of the adaption of the developed method of structural identification for the devices of electric traction system. Secondly, it lies in the proper development of the new method of weight function. And finally, it lies in the solution of the Wiener

  18. THE DEVELOPMENT OF A LUBRICANT TRACTION MEASUREMENT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-shuang; ZHANG Luo-ping; YANG Bo-yuan

    2011-01-01

    A ball-disc traction test rig is improved through the development of a lubricant traction measurement system,consisting of a resonance force sensitive quartz sensor,a circuit of the sensor and a rigid bracket jointed by a frictionless hinge.The traction coefficients of a kind of domestic lubricating oil were measured at various normal loads,rolling velocities,lubricant inlet temperatures and slide-to-roll ratios on a ball-disc traction test rig equipped with this traction measurement system.The results show that the traction test curve is smooth and the data enjoy a good accuracy,which indicates that the design of the lubricant traction measurement system is reasonable and the precision of the system is high,especially,at high temperature,high rolling speed and small slide-to-roll ratio.

  19. Microfluidic traction force microscopy to study mechanotransduction in angiogenesis.

    Science.gov (United States)

    Boldock, Luke; Wittkowske, Claudia; Perrault, Cecile M

    2017-07-01

    The formation of new blood vessels from existing vasculature, angiogenesis, is driven by coordinated endothelial cell migration and matrix remodeling in response to local signals. Recently, a growing body of evidence has shown that mechanotransduction, along with chemotransduction, is a major regulator of angiogenesis. Mechanical signals, such as fluid shear stress and substrate mechanics, influence sprouting and network formation, but the mechanisms behind this relationship are still unclear. Here, we present cellular traction forces as possible effectors activated by mechanosensing to mediate matrix remodeling, and encourage the use of TFM to study mechanotransduction in angiogenesis. We also suggest that deciphering the response of EC to mechanical signals could reveal an optimal angiogenic mechanical environment, and provide insight into development, wound healing, the initiation and growth of tumors, and new strategies for tissue engineering. © 2017 John Wiley & Sons Ltd.

  20. Exploring Asynchronous Many-Task Runtime Systems toward Extreme Scales

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Samuel [O8953; Baker, Gavin Matthew; Gamell, Marc [Rutgers U; Hollman, David [08953; Sjaardema, Gregor [SNL; Kolla, Hemanth [SNL; Teranishi, Keita; Wilke, Jeremiah J; Slattengren, Nicole [SNL; Bennett, Janine Camille

    2015-10-01

    Major exascale computing reports indicate a number of software challenges to meet the dramatic change of system architectures in near future. While several-orders-of-magnitude increase in parallelism is the most commonly cited of those, hurdles also include performance heterogeneity of compute nodes across the system, increased imbalance between computational capacity and I/O capabilities, frequent system interrupts, and complex hardware architectures. Asynchronous task-parallel programming models show a great promise in addressing these issues, but are not yet fully understood nor developed su ciently for computational science and engineering application codes. We address these knowledge gaps through quantitative and qualitative exploration of leading candidate solutions in the context of engineering applications at Sandia. In this poster, we evaluate MiniAero code ported to three leading candidate programming models (Charm++, Legion and UINTAH) to examine the feasibility of these models that permits insertion of new programming model elements into an existing code base.

  1. Three-Dimensional Reflectance Traction Microscopy.

    Directory of Open Access Journals (Sweden)

    Jihan Kim

    Full Text Available Cells in three-dimensional (3D environments exhibit very different biochemical and biophysical phenotypes compared to the behavior of cells in two-dimensional (2D environments. As an important biomechanical measurement, 2D traction force microscopy can not be directly extended into 3D cases. In order to quantitatively characterize the contraction field, we have developed 3D reflectance traction microscopy which combines confocal reflection imaging and partial volume correlation postprocessing. We have measured the deformation field of collagen gel under controlled mechanical stress. We have also characterized the deformation field generated by invasive breast cancer cells of different morphologies in 3D collagen matrix. In contrast to employ dispersed tracing particles or fluorescently-tagged matrix proteins, our methods provide a label-free, computationally effective strategy to study the cell mechanics in native 3D extracellular matrix.

  2. Validation tool for traction force microscopy.

    Science.gov (United States)

    Jorge-Peñas, A; Muñoz-Barrutia, A; de-Juan-Pardo, E M; Ortiz-de-Solorzano, C

    2015-01-01

    Traction force microscopy (TFM) is commonly used to estimate cells' traction forces from the deformation that they cause on their substrate. The accuracy of TFM highly depends on the computational methods used to measure the deformation of the substrate and estimate the forces, and also on the specifics of the experimental set-up. Computer simulations can be used to evaluate the effect of both the computational methods and the experimental set-up without the need to perform numerous experiments. Here, we present one such TFM simulator that addresses several limitations of the existing ones. As a proof of principle, we recreate a TFM experimental set-up, and apply a classic 2D TFM algorithm to recover the forces. In summary, our simulator provides a valuable tool to study the performance, refine experimentally, and guide the extraction of biological conclusions from TFM experiments.

  3. The characteristics of the combustion process occurring under real operating conditions of traction

    Science.gov (United States)

    Longwic, R.; Sander, P.

    2016-09-01

    The authors deal with the issues of the Diesel engine under dynamic conditions. The conditions of the dynamic operation of the engine have most frequently been mapped by the method of free acceleration of the engine caused by the change of the position of the fuel dose lever. The article presents the results of indication of the traction Diesel engine under real operating conditions. This allows for the use of a mobile system to indicate the AVL engine built in the vehicle in research. We analysed a number of thermodynamic parameters of the combustion process in various dynamic states, typical for the process of actual operation of the engine, such as working in start-up conditions and immediately after, working in conditions of acceleration and coasting. Formulated conclusions significantly expand the area of knowledge concerning the functioning of the internal combustion engine in dynamic conditions.

  4. Digital Model of Railway Electric Traction Lines

    Science.gov (United States)

    Garg, Rachana; Mahajan, Priya; Kumar, Parmod

    2016-08-01

    The characteristic impedance and propagation constant define the behavior of signal propagation over the transmission lines. The digital model for railway traction lines which includes railway tracks is developed, using curve fitting technique in MATLAB. The sensitivity of this model has been computed with respect to frequency. The digital sensitivity values are compared with the values of analog sensitivity. The developed model is useful for digital protection, integrated operation, control and planning of the system.

  5. Digital Model of Railway Electric Traction Lines

    Science.gov (United States)

    Garg, Rachana; Mahajan, Priya; Kumar, Parmod

    2017-08-01

    The characteristic impedance and propagation constant define the behavior of signal propagation over the transmission lines. The digital model for railway traction lines which includes railway tracks is developed, using curve fitting technique in MATLAB. The sensitivity of this model has been computed with respect to frequency. The digital sensitivity values are compared with the values of analog sensitivity. The developed model is useful for digital protection, integrated operation, control and planning of the system.

  6. Proximal sural traction neurectomy during transtibial amputations.

    Science.gov (United States)

    Tintle, Scott M; Donohue, Michael A; Shawen, Scott; Forsberg, Jonathan A; Potter, Benjamin K

    2012-02-01

    Symptomatic neuroma formation after trauma-related transtibial amputations remains a clinical problem. The sural nerve is frequently overlooked in its vulnerable subcutaneous location in the posterior myofasciocutaneous flap and commonly leads to chronic pain and decreased prosthesis use. The standard sural traction neurectomy may actually predispose the sural neuroma to form in a region that becomes symptomatic with prosthesis wear. The proposed modified proximal sural traction neurectomy using a standard or extended posterior flap begins with identification of the sural nerve in the subcutaneous tissue of the distal flap in identical fashion to a standard sural neurectomy. In the proximal posterior flap, a limited anterior approach is then performed and gentle traction on the distal end of the sural nerve aids in the identification of the most proximally accessible portion of the medial sural cutaneous nerve. After locating the medial sural cutaneous nerve proximally, a neurectomy at this location is performed, allowing the retraction of the nerve into a healthy tissue bed substantially more proximal than with a standard sural neurectomy. This technique ensures that the resulting neuroma does not form directly at the distal end of the residual limb where it is, in our experience, more likely to become symptomatic.

  7. Synchronization of Asynchronous Switched Boolean Network.

    Science.gov (United States)

    Zhang, Hao; Wang, Xingyuan; Lin, Xiaohui

    2015-01-01

    In this paper, the complete synchronizations for asynchronous switched Boolean network with free Boolean sequence controllers and close-loop controllers are studied. First, the basic asynchronous switched Boolean network model is provided. With the method of semi-tensor product, the Boolean dynamics is translated into linear representation. Second, necessary and sufficient conditions for ASBN synchronization with free Boolean sequence control and close-loop control are derived, respectively. Third, some illustrative examples are provided to show the efficiency of the proposed methods.

  8. A simple asynchronous replica-exchange implementation

    CERN Document Server

    Bussi, Giovanni

    2008-01-01

    We discuss the possibility of implementing asynchronous replica-exchange (or parallel tempering) molecular dynamics. In our scheme, the exchange attempts are driven by asynchronous messages sent by one of the computing nodes, so that different replicas are allowed to perform a different number of time-steps between subsequent attempts. The implementation is simple and based on the message-passing interface (MPI). We illustrate the advantages of our scheme with respect to the standard synchronous algorithm and we benchmark it for a model Lennard-Jones liquid on an IBM-LS21 blade center cluster.

  9. Handbook of asynchronous machines with variable speed

    CERN Document Server

    Razik, Hubert

    2013-01-01

    This handbook deals with the asynchronous machine in its close environment. It was born from a reflection on this electromagnetic converter whose integration in industrial environments takes a wide part. Previously this type of motor operated at fixed speed, from now on it has been integrated more and more in processes at variable speed. For this reason it seemed useful, or necessary, to write a handbook on the various aspects from the motor in itself, via the control and while finishing by the diagnosis aspect. Indeed, an asynchronous motor is used nowadays in industry where variation speed a

  10. A Provably Secure Asynchronous Proactive RSA Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; LI Qiang; CHEN Ke-fei

    2005-01-01

    The drawback of the first asynchronous proactive RSA scheme presented by Zhou in 2001, is that the se curity definition and security proof do not follow the approach of provable security. This paper presented a provably secure asynchronous proactive RSA scheme, which includes three protocols: initial key distribution protocol,signature generation protocol and share refreshing protocol. Taken these protocols together, a complete provably secure proactive RSA scheme was obtained. And the efficiency of the scheme is approximate to that of the scheme of Zhou.

  11. Processor arrays with asynchronous TDM optical buses

    Science.gov (United States)

    Li, Y.; Zheng, S. Q.

    1997-04-01

    We propose a pipelined asynchronous time division multiplexing optical bus. Such a bus can use one of the two hardwared priority schemes, the linear priority scheme and the round-robin priority scheme. Our simulation results show that the performances of our proposed buses are significantly better than the performances of known pipelined synchronous time division multiplexing optical buses. We also propose a class of processor arrays connected by pipelined asynchronous time division multiplexing optical buses. We claim that our proposed processor array not only have better performance, but also have better scalabilities than the existing processor arrays connected by pipelined synchronous time division multiplexing optical buses.

  12. Three-dimensional quantification of cellular traction forces and mechanosensing of thin substrata by fourier traction force microscopy.

    Science.gov (United States)

    del Álamo, Juan C; Meili, Ruedi; Álvarez-González, Begoña; Alonso-Latorre, Baldomero; Bastounis, Effie; Firtel, Richard; Lasheras, Juan C

    2013-01-01

    We introduce a novel three-dimensional (3D) traction force microscopy (TFM) method motivated by the recent discovery that cells adhering on plane surfaces exert both in-plane and out-of-plane traction stresses. We measure the 3D deformation of the substratum on a thin layer near its surface, and input this information into an exact analytical solution of the elastic equilibrium equation. These operations are performed in the Fourier domain with high computational efficiency, allowing to obtain the 3D traction stresses from raw microscopy images virtually in real time. We also characterize the error of previous two-dimensional (2D) TFM methods that neglect the out-of-plane component of the traction stresses. This analysis reveals that, under certain combinations of experimental parameters (cell size, substratums' thickness and Poisson's ratio), the accuracy of 2D TFM methods is minimally affected by neglecting the out-of-plane component of the traction stresses. Finally, we consider the cell's mechanosensing of substratum thickness by 3D traction stresses, finding that, when cells adhere on thin substrata, their out-of-plane traction stresses can reach four times deeper into the substratum than their in-plane traction stresses. It is also found that the substratum stiffness sensed by applying out-of-plane traction stresses may be up to 10 times larger than the stiffness sensed by applying in-plane traction stresses.

  13. Three-dimensional quantification of cellular traction forces and mechanosensing of thin substrata by fourier traction force microscopy.

    Directory of Open Access Journals (Sweden)

    Juan C del Álamo

    Full Text Available We introduce a novel three-dimensional (3D traction force microscopy (TFM method motivated by the recent discovery that cells adhering on plane surfaces exert both in-plane and out-of-plane traction stresses. We measure the 3D deformation of the substratum on a thin layer near its surface, and input this information into an exact analytical solution of the elastic equilibrium equation. These operations are performed in the Fourier domain with high computational efficiency, allowing to obtain the 3D traction stresses from raw microscopy images virtually in real time. We also characterize the error of previous two-dimensional (2D TFM methods that neglect the out-of-plane component of the traction stresses. This analysis reveals that, under certain combinations of experimental parameters (cell size, substratums' thickness and Poisson's ratio, the accuracy of 2D TFM methods is minimally affected by neglecting the out-of-plane component of the traction stresses. Finally, we consider the cell's mechanosensing of substratum thickness by 3D traction stresses, finding that, when cells adhere on thin substrata, their out-of-plane traction stresses can reach four times deeper into the substratum than their in-plane traction stresses. It is also found that the substratum stiffness sensed by applying out-of-plane traction stresses may be up to 10 times larger than the stiffness sensed by applying in-plane traction stresses.

  14. Asynchronous replica exchange software for grid and heterogeneous computing

    Science.gov (United States)

    Gallicchio, Emilio; Xia, Junchao; Flynn, William F.; Zhang, Baofeng; Samlalsingh, Sade; Mentes, Ahmet; Levy, Ronald M.

    2015-11-01

    Parallel replica exchange sampling is an extended ensemble technique often used to accelerate the exploration of the conformational ensemble of atomistic molecular simulations of chemical systems. Inter-process communication and coordination requirements have historically discouraged the deployment of replica exchange on distributed and heterogeneous resources. Here we describe the architecture of a software (named ASyncRE) for performing asynchronous replica exchange molecular simulations on volunteered computing grids and heterogeneous high performance clusters. The asynchronous replica exchange algorithm on which the software is based avoids centralized synchronization steps and the need for direct communication between remote processes. It allows molecular dynamics threads to progress at different rates and enables parameter exchanges among arbitrary sets of replicas independently from other replicas. ASyncRE is written in Python following a modular design conducive to extensions to various replica exchange schemes and molecular dynamics engines. Applications of the software for the modeling of association equilibria of supramolecular and macromolecular complexes on BOINC campus computational grids and on the CPU/MIC heterogeneous hardware of the XSEDE Stampede supercomputer are illustrated. They show the ability of ASyncRE to utilize large grids of desktop computers running the Windows, MacOS, and/or Linux operating systems as well as collections of high performance heterogeneous hardware devices.

  15. Asynchronous Replica Exchange Software for Grid and Heterogeneous Computing

    Science.gov (United States)

    Gallicchio, Emilio; Xia, Junchao; Flynn, William F.; Zhang, Baofeng; Samlalsingh, Sade; Mentes, Ahmet; Levy, Ronald M.

    2015-01-01

    Parallel replica exchange sampling is an extended ensemble technique often used to accelerate the exploration of the conformational ensemble of atomistic molecular simulations of chemical systems. Inter-process communication and coordination requirements have historically discouraged the deployment of replica exchange on distributed and heterogeneous resources. Here we describe the architecture of a software (named ASyncRE) for performing asynchronous replica exchange molecular simulations on volunteered computing grids and heterogeneous high performance clusters. The asynchronous replica exchange algorithm on which the software is based avoids centralized synchronization steps and the need for direct communication between remote processes. It allows molecular dynamics threads to progress at different rates and enables parameter exchanges among arbitrary sets of replicas independently from other replicas. ASyncRE is written in Python following a modular design conducive to extensions to various replica exchange schemes and molecular dynamics engines. Applications of the software for the modeling of association equilibria of supramolecular and macromolecular complexes on BOINC campus computational grids and on the CPU/MIC heterogeneous hardware of the XSEDE Stampede supercomputer are illustrated. They show the ability of ASyncRE to utilize large grids of desktop computers running the Windows, MacOS, and/or Linux operating systems as well as collections of high performance heterogeneous hardware devices. PMID:27103749

  16. Regulation of unbalanced electromagnetic moment in mutual loading systems of electric machines of traction rolling stock and multiple unit of mainline and industrial transport

    Directory of Open Access Journals (Sweden)

    A. M. Afanasov

    2014-12-01

    Full Text Available Purpose. The research data are aimed to identify the regulatory principles of unbalanced electromagnetic moment of mutually loaded electric machines of traction rolling stock and multiple unit of main and industrial transport. The purpose of this study is energy efficiency increase of the testing of traction electric machines of direct and pulse current using the improvement methods of their mutual loading, including the principles of automatic regulation of mutual loading system. Methodology. The general theoretical provisions and principles of system approach to the theoretical electric engineering, the theory of electric machines and theoretical mechanics are the methodological basis of this research. The known methods of analysis of electromagnetic and electromechanical processes in electrical machines of direct and pulse current are used in the study. Methods analysis of loading modes regulation of traction electric machines was conducted using the generalized scheme of mutual loading. It is universal for all known methods to cover the losses of idling using the electric power. Findings. The general management principles of mutual loading modes of the traction electric machines of direct and pulse current by regulating their unbalanced electric magnetic moment were developed. Regulatory options of unbalanced electromagnetic moment are examined by changing the difference of the magnetic fluxes of mutually loaded electric machines, the current difference of electric machines anchors, the difference of the angular velocities of electric machines shafts. Originality. It was obtained the scientific basis development to improve the energy efficiency test methods of traction electric machines of direct and pulse current. The management principles of mutual loading modes of traction electric machines were formulated. For the first time it is introduced the concept and developed the principles of regulation of unbalanced electromagnetic moment in

  17. Concepts of electrical traction equipments for the operation without overhead cables; Konzepte elektrischer Antriebsausruestungen fuer Betrieb ohne Oberleitung

    Energy Technology Data Exchange (ETDEWEB)

    Fassbinder, Stefan [Deutsches Kupferinstitut, Duesseldorf (Germany)

    2012-03-15

    High energy costs and complex operating conditions meet the development of unusual drive concepts for locomotives and trainsets. In several areas, the traction accumulator could play an important role. There exist railway lines, at which electrification cannot be considered at present. Innovative traction concepts already are implemented or in principle available for the operation of these railway lines. These concepts aim to take along affordable energy for diesel-hybrid vehicles or also for electric vehicles by storage and/or to utilize the fuel for the diesel engine better.

  18. TRACTION-EXTENDED THERAPY OF PATIENTS WITH LUMBAR DEGENERATIVE DISEASE

    Directory of Open Access Journals (Sweden)

    V. A. Zhirnov

    2013-01-01

    Full Text Available Based on the survey of 148 patients with an lumbar degenerative disease, there have been studied immediate and medium-term results of the comprehensive conservative treatment of the patients with and without application of traction exposure on the spine. It was found out that the traction of the spine leads to a quicker and more durable relief of symptoms in comparison with the control groups where traction therapy wasn't carried out. Application of the traction-extended therapy in three planes with a usage of robotized set for dry skeletal traction of a new generation KinetracKNX-7000 is proved to increase the effectiveness of treatment for the patients with stated pathology, fasten regress of the pain syndrome and clinical symptomatology, lead to more durable and lasting remission of the desease, in comparison with the patients that had traction of the spine in one plane only during the treatment.

  19. [Potentialities of traction therapy for diskogenic compressive radicular syndromes].

    Science.gov (United States)

    Ziniakov, N N; Ziniakov, N T

    2009-01-01

    This study included 78 patients with lumbar subligamentary herniation. Based on their clinical and functional examination, several variants of diskogenic radiculopathies were distinguished. Special emphasis was laid on the evaluation of efficiency of underwater vertical traction in these patients. The proposed method was shown to produce better effect than underwater horizontal traction when used for the treatment of both axonopathies and axonomyelinopathies. The efficiency of underwater vertical traction applied to the treatment of axonopathies appears to be higher than in patients with axonomyelinopathies.

  20. Measurement of cell traction forces with ImageJ.

    Science.gov (United States)

    Martiel, Jean-Louis; Leal, Aldo; Kurzawa, Laetitia; Balland, Martial; Wang, Irene; Vignaud, Timothée; Tseng, Qingzong; Théry, Manuel

    2015-01-01

    The quantification of cell traction forces requires three key steps: cell plating on a deformable substrate, measurement of substrate deformation, and the numerical estimation of the corresponding cell traction forces. The computing steps to measure gel deformation and estimate the force field have somehow limited the adoption of this method in cell biology labs. Here we propose a set of ImageJ plug-ins so that every lab equipped with a fluorescent microscope can measure cell traction forces.

  1. TRACTION-EXTENDED THERAPY OF PATIENTS WITH LUMBAR DEGENERATIVE DISEASE

    OpenAIRE

    V. A. Zhirnov; D. P. Krest'yanov; A. K. Vasil'kin

    2013-01-01

    Based on the survey of 148 patients with an lumbar degenerative disease, there have been studied immediate and medium-term results of the comprehensive conservative treatment of the patients with and without application of traction exposure on the spine. It was found out that the traction of the spine leads to a quicker and more durable relief of symptoms in comparison with the control groups where traction therapy wasn't carried out. Application of the traction-extended therapy in three plan...

  2. Convergence of some asynchronous nonlinear multisplitting methods

    Science.gov (United States)

    Szyld, Daniel B.; Xu, Jian-Jun

    2000-09-01

    Frommer's nonlinear multisplitting methods for solving nonlinear systems of equations are extended to the asynchronous setting. Block methods are extended to include overlap as well. Several specific cases are discussed. Sufficient conditions to guarantee their local convergence are given. A numerical example is presented illustrating the performance of the new approach.

  3. Increasing Student Engagement Using Asynchronous Learning

    Science.gov (United States)

    Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

    2015-01-01

    Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

  4. Asynchronous Rumor Spreading on Random Graphs

    CERN Document Server

    Panagiotou, Konstantinos

    2016-01-01

    We perform a thorough study of various characteristics of the asynchronous push-pull protocol for spreading a rumor on Erd\\H{o}s-R\\'enyi random graphs $G_{n,p}$, for any $p>c\\ln(n)/n$ with $c>1$. In particular, we provide a simple strategy for analyzing the asynchronous push-pull protocol on arbitrary graph topologies and apply this strategy to $G_{n,p}$. We prove tight bounds of logarithmic order for the total time that is needed until the information has spread to all nodes. Surprisingly, the time required by the asynchronous push-pull protocol is asymptotically almost unaffected by the average degree of the graph. Similarly tight bounds for Erd\\H{o}s-R\\'enyi random graphs have previously only been obtained for the synchronous push protocol, where it has been observed that the total running time increases significantly for sparse random graphs. Finally, we quantify the robustness of the protocol with respect to transmission and node failures. Our analysis suggests that the asynchronous protocols are particu...

  5. Maintaining High Assurance in Asynchronous Messaging

    Science.gov (United States)

    2015-10-24

    be inconvenient and not consistent with normal dialog communication. II. PRIOR WORK A proliferation of standards for asynchronous messaging has...Software Technology Conference, “A Persona -Based Framework for Flexible Delegation and Least Privilege,” Las Vegas, Nevada, May 2008. [25] William

  6. Increasing Student Engagement Using Asynchronous Learning

    Science.gov (United States)

    Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

    2015-01-01

    Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

  7. FIFO Buffer for Asynchronous Data Streams

    Science.gov (United States)

    Bascle, K. P.

    1985-01-01

    Variable-rate, asynchronous data signals from up to four measuring instruments or other sources combined in first-in/first-out (FIFO) buffer for transmission on single channel. Constructed in complementary metal-oxide-semiconductor (CMOS) logic, buffer consumes low power (only 125 mW at 5V) and conforms to aerospace standards of reliability and maintainability.

  8. Asynchronous stream processing with S-Net

    NARCIS (Netherlands)

    Grelck, C.; Scholz, S.-B.; Shafarenko, A.

    2010-01-01

    We present the rationale and design of S-Net, a coordination language for asynchronous stream processing. The language achieves a near-complete separation between the application code, written in any conventional programming language, and the coordination/communication code written in S-Net. Our app

  9. Mathematical framework for traction force microscopy

    Directory of Open Access Journals (Sweden)

    Michel R.

    2013-12-01

    Full Text Available This paper deals with the Traction Force Microscopy (TFM problem. It consists in obtaining stresses by solving an inverse problem in an elastic medium, from known experimentally measured displacements. In this article, the application is the determination of the stresses exerted by a living cell at the surface of an elastic gel. We propose an abstract framework which formulates this inverse problem as a constrained minimization one. The mathematical constraints express the biomechanical conditions that the stress field must satisfy. From this framework, two methods currently used can be derived, the adjoint method (AM and the Fourier Transform Traction Cytometry (FTTC method. An improvement of the FTTC method is also derived using this framework. The numerical results are compared and show the advantage of the AM, in particular its ability to capture details more accurately. Cet article est consacré au problème de la Microscopie à Force de Traction (TFM. Ce problème consiste à déterminer les contraintes exercées par une cellule lors de sa migration sur un substrat élastique à partir d’une mesure expérimentale des déplacements induits dans ce substrat. Mathématiquement, il s’agit de résoudre un problème inverse pour lequel nous proposons une formulation abstraite de type optimisation sous contraintes. Les contraintes mathématiques expriment les constraintes biomécaniques que doit satisfaire le champ de contraintes exercé par la cellule. Ce cadre abstrait permet de retrouver deux des méthodes de résolution utilisées en pratique, à savoir la méthode adjointe (AM et la méthode de Cytométrie de Traction par Transformée de Fourier (FTTC. Il permet aussi d’ameliorer la méthode FTTC. Les résultats numériques obtenus sont ensuite comparés et démontrent l’avantage de la méthode adjointe, en particulier par sa capacité à capturer des détails avec une meilleure précision.

  10. Super-Resolved Traction Force Microscopy (STFM).

    Science.gov (United States)

    Colin-York, Huw; Shrestha, Dilip; Felce, James H; Waithe, Dominic; Moeendarbary, Emad; Davis, Simon J; Eggeling, Christian; Fritzsche, Marco

    2016-04-13

    Measuring small forces is a major challenge in cell biology. Here we improve the spatial resolution and accuracy of force reconstruction of the well-established technique of traction force microscopy (TFM) using STED microscopy. The increased spatial resolution of STED-TFM (STFM) allows a greater than 5-fold higher sampling of the forces generated by the cell than conventional TFM, accessing the nano instead of the micron scale. This improvement is highlighted by computer simulations and an activating RBL cell model system.

  11. The Study of Several Variants of the Traction Drive with Middle-Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Martin Pittermann

    2008-01-01

    Full Text Available This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight of traction vehicles. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase – middle frequency transformer (single phase – output converter (single phase voltage-source active rectifier + three phase voltage-source inverter - traction motor. This configuration can minimize traction transformer weight against topology with classical 50Hz traction transformer. Several variants of innovative topologies of the traction vehicles fulfil the weight reduce requirements have beenpresented.

  12. Traction force and its regulation during cytokinesis in Dictyostelium cells.

    Science.gov (United States)

    Jahan, Md Golam Sarowar; Yumura, Shigehiko

    2017-09-01

    Cytokinesis is the final stage of cell division. Dictyostelium cells have multiple modes of cytokinesis, including cytokinesis A, B and C. Cytokinesis A is a conventional mode, which depends on myosin II in the contractile ring. Myosin II null cells divide depending on substratum-attachment (cytokinesis B) or in a multi-polar fashion independent of the cell cycle (cytokinesis C). We investigated the traction stress exerted by dividing cells in the three different modes using traction force microscopy. In all cases, the traction forces were directed inward from both poles. Interestingly, the traction stress of cytokinesis A was the smallest of the three modes. Latrunculin B, an inhibitor of actin polymerization, completely diminished the traction stress of dividing cells, but blebbistatin, an inhibitor of myosin II ATPase, increased the traction stress. Myosin II is proposed to contribute to the detachment of cell body from the substratum. When the cell-substratum attachment was artificially strengthened by a poly-lysine coating, wild type cells increased their traction stress in contrast to myosin II null and other cytokinesis-deficient mutant cells, which suggests that wild type cells may increase their own power to conduct their cytokinesis. The cytokinesis-deficient mutants frequently divided unequally, whereas wild type cells divided equally. A traction stress imbalance between two daughter halves was correlated with cytokinesis failure. We discuss the regulation of cell shape changes during cell division through mechanosensing. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Microtubule depolymerization induces traction force increase through two distinct pathways.

    Science.gov (United States)

    Rape, Andrew; Guo, Wei-hui; Wang, Yu-li

    2011-12-15

    Traction forces increase after microtubule depolymerization; however, the signaling mechanisms underlying this, in particular the dependence upon myosin II, remain unclear. We investigated the mechanism of traction force increase after nocodazole-induced microtubule depolymerization by applying traction force microscopy to cells cultured on micropatterned polyacrylamide hydrogels to obtain samples of homogeneous shape and size. Control cells and cells treated with a focal adhesion kinase (FAK) inhibitor showed similar increases in traction forces, indicating that the response is independent of FAK. Surprisingly, pharmacological inhibition of myosin II did not prevent the increase of residual traction forces upon nocodazole treatment. This increase was abolished upon pharmacological inhibition of FAK. These results suggest two distinct pathways for the regulation of traction forces. First, microtubule depolymerization activates a myosin-II-dependent mechanism through a FAK-independent pathway. Second, microtubule depolymerization also enhances traction forces through a myosin-II-independent, FAK-regulated pathway. Traction forces are therefore regulated by a complex network of complementary signals and force-generating mechanisms.

  14. Potential Development of Vehicle Traction Levitation Systems with Magnetic Suspension

    Directory of Open Access Journals (Sweden)

    A.V. Kireev

    2015-03-01

    Full Text Available Below is given the brief analysis of development trend for vehicle traction levitation systems with magnetic suspension. It is presented the assessment of potential development of traction levitation systems in terms of their simplicity. The examples are considered of technical solutions focused on reducing the complexity of transport systems. It is proposed the forecast of their further development.

  15. Development of Traction Drive Motors for the Toyota Hybrid System

    Science.gov (United States)

    Kamiya, Munehiro

    Toyota Motor Corporation developed in 2005 a new hybrid system for a large SUV. This system included the new development of a high-speed traction drive motor achieving a significant increase in power weight ratio. This paper provides an overview of the hybrid system, discusses the characteristics required of a traction drive motor, and presents the technologies employed in the developed motor.

  16. Traction for low-back pain with or without sciatica

    NARCIS (Netherlands)

    Wegner, I.; Widyahehening, I.S.; van Tulder, M.W.; Blomberg, S.E.I.; de Vet, H.C.W.; Brønfort, G.; Bouter, L.M.; van der Heijden, G.J.

    2013-01-01

    Background Traction has been used to treat low-back pain (LBP), often in combination with other treatments. We included both manual and machine-delivered traction in this review. This is an update of a Cochrane review first published in 1995, and previously updated in 2006. Objectives To assess the

  17. High-resolution traction force microscopy.

    Science.gov (United States)

    Plotnikov, Sergey V; Sabass, Benedikt; Schwarz, Ulrich S; Waterman, Clare M

    2014-01-01

    Cellular forces generated by the actomyosin cytoskeleton and transmitted to the extracellular matrix (ECM) through discrete, integrin-based protein assemblies, that is, focal adhesions, are critical to developmental morphogenesis and tissue homeostasis, as well as disease progression in cancer. However, quantitative mapping of these forces has been difficult since there has been no experimental technique to visualize nanonewton forces at submicrometer spatial resolution. Here, we provide detailed protocols for measuring cellular forces exerted on two-dimensional elastic substrates with a high-resolution traction force microscopy (TFM) method. We describe fabrication of polyacrylamide substrates labeled with multiple colors of fiducial markers, functionalization of the substrates with ECM proteins, setting up the experiment, and imaging procedures. In addition, we provide the theoretical background of traction reconstruction and experimental considerations important to design a high-resolution TFM experiment. We describe the implementation of a new algorithm for processing of images of fiducial markers that are taken below the surface of the substrate, which significantly improves data quality. We demonstrate the application of the algorithm and explain how to choose a regularization parameter for suppression of the measurement error. A brief discussion of different ways to visualize and analyze the results serves to illustrate possible uses of high-resolution TFM in biomedical research. © 2014 Elsevier Inc. All rights reserved.

  18. Towards Single Cell Traction Microscopy within 3D Collagen Matrices

    Science.gov (United States)

    Hall, Matthew S.; Long, Rong; Feng, Xinzeng; Huang, YuLing; Hui, Chung-Yuen; Wu, Mingming

    2013-01-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion, and migration. Cells require the three dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, current understanding of cell-ECM and cell-cell mechanical interactions is largely derived from 2D cell traction force microscopy, in which cells are cultured on a flat substrate. 3D cell traction microscopy is emerging for mapping traction fields of single animal cells embedded in either synthetic or natively derived fibrous gels. We discuss here the development of 3D cell traction microscopy, its current limitations, and perspectives on the future of this technology. Emphasis is placed on strategies for applying 3D cell traction microscopy to individual tumor cells migration within collagen gels. PMID:23806281

  19. Toward single cell traction microscopy within 3D collagen matrices.

    Science.gov (United States)

    Hall, Matthew S; Long, Rong; Feng, Xinzeng; Huang, Yuling; Hui, Chung-Yuen; Wu, Mingming

    2013-10-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion, and migration. Cells require the three-dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, current understanding of cell-ECM and cell-cell mechanical interactions is largely derived from 2D cell traction force microscopy, in which cells are cultured on a flat substrate. 3D cell traction microscopy is emerging for mapping traction fields of single animal cells embedded in either synthetic or natively derived fibrous gels. We discuss here the development of 3D cell traction microscopy, its current limitations, and perspectives on the future of this technology. Emphasis is placed on strategies for applying 3D cell traction microscopy to individual tumor cell migration within collagen gels. © 2013 Elsevier Inc. All rights reserved.

  20. Computed tomographic evaluation of lumbar spinal structures during traction.

    Science.gov (United States)

    Sari, Hidayet; Akarirmak, Ulkü; Karacan, Ilhan; Akman, Haluk

    2005-01-01

    In the previous studies, it is reported that traction diminishes the compressive load on intervertebral discs, reduces herniation, stretches lumbar spinal muscle and ligaments, decreases muscle spasm, and widens intervertebral foramina. The aim of this study was to evaluate the effects of horizontal motorized static traction on spinal anatomic structures (herniated area, spinal canal area, intervertebral disc heights, neural foraminal diameter, and m.psoas diameter) by quantitative measures in patients with lumbar disc herniation (LDH). At the same time the effect of traction in different localizations (median and posterolateral herniation) and at different levels (L4-L5 and L5-S1) was assessed. Thirty two patients with acute LDH participated in the study. A special traction system was used to apply horizontally-motorized static lumbar traction. Before and during traction a CT- scan was made to observe the changes in the area of spinal canal and herniated disc material, in the width of neural foramina, intervertebral disc heights, and in the thickness of psoas muscle. During traction, the area of protruded disc area, and the thickness of psoas muscle decreased 24.5% (p = 0.0001), and 5.7% (p = 0.0001), respectively. The area of the spinal canal and the width of the neural foramen increased 21.6% (p = 0.0001) and 26.7% (p = 0.0001), respectively. The anterior intervertebral disc height remained unchanged with traction however the posterior intervertebral disc height was significantly expanded. This study is the first to evaluated in detail and quantitatively the effect of motorized horizontal lumbar spinal traction on spinal structures and herniated area. According to detailed measures it was concluded that during traction of individuals with acute LDH there was a reduction of the size of the herniation, increased space within the spinal canal, widening of the neural foramina, and decreased thickness of the psoas muscle.

  1. Inhibition Controls Asynchronous States of Neuronal Networks

    Science.gov (United States)

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks. PMID:27274721

  2. Computing by Temporal Order: Asynchronous Cellular Automata

    Directory of Open Access Journals (Sweden)

    Michael Vielhaber

    2012-08-01

    Full Text Available Our concern is the behaviour of the elementary cellular automata with state set 0,1 over the cell set Z/nZ (one-dimensional finite wrap-around case, under all possible update rules (asynchronicity. Over the torus Z/nZ (n<= 11,we will see that the ECA with Wolfram rule 57 maps any v in F_2^n to any w in F_2^n, varying the update rule. We furthermore show that all even (element of the alternating group bijective functions on the set F_2^n = 0,...,2^n-1, can be computed by ECA57, by iterating it a sufficient number of times with varying update rules, at least for n <= 10. We characterize the non-bijective functions computable by asynchronous rules.

  3. Low Latency High Throughout Circular Asynchronous FIFO

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong; ZHOU Runde

    2008-01-01

    This paper describes a circular first in first out (FIFO) and its protocols which have a very low la-tency while still maintaining high throughput. Unlike the existing serial FIFOs based on asynchronous micro-pipelines, this FIFO's cells communicate directly with the input and output ports through a common bus, which effectively eliminates the data movement from the input port to the output port, thereby reducing the latency and the power consumption. Furthermore, the latency does not increase with the number of FIFO stages. Single-track asynchronous protocols are used to simplify the FIFO controller design, with only three C-gates needed in each cell controller, which substantially reduces the area. Simulations with the TSMC 0.25 Ijm CMOS logic process show that the latency of the 4-stage FIFO is less than 581 ps and the throughput is higher than 2.2 GHz.

  4. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed...... as a synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... be performed as an asynchronous (parallel) iteration: Only a few components are changed in each stepand this calculation is in general based on components from differentprevious iterates. For the asynchronous iteration it turns out thatsimple tests of existence and non-existence can be based...

  5. Inhibition Controls Asynchronous States of Neuronal Networks.

    Science.gov (United States)

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks.

  6. Fast Asynchronous Data Communication Via Fiber Optics

    Science.gov (United States)

    Bergman, Larry A.; Tell, Robert G.

    1989-01-01

    Transmitter and receiver devised for asynchronous digital communication via optical fiber at rates above 100 Mb/s. Transmitter converts parallel data to serial for high-speed transmission; receiver recovers clock signal and converts data back to parallel. No phase-lock loops used. New receiver design avoids over-sampling altogether. Local sampling oscillator operating nominally at clock frequency generates N clock signals of equally spaced phase, used to clock incoming data into N separate shift registers.

  7. Asynchronous exponential growth of a bacterial population

    Directory of Open Access Journals (Sweden)

    Mohamed Boulanouar

    2014-01-01

    Full Text Available In this work, we complete a study started earlier in [1,2] wherein a model of growing bacterial population has been the matter of a mathematical analysis. We show that the full model is governed by a strongly continuous semigroup. Beside the positivity and the irreducibility of the generated semigroup, we describe its asymptotic behavior in the uniform topology which leads to the asynchronous exponential growth of the bacterial population.

  8. Asynchronous event-based binocular stereo matching.

    Science.gov (United States)

    Rogister, Paul; Benosman, Ryad; Ieng, Sio-Hoi; Lichtsteiner, Patrick; Delbruck, Tobi

    2012-02-01

    We present a novel event-based stereo matching algorithm that exploits the asynchronous visual events from a pair of silicon retinas. Unlike conventional frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of the biological retina. Our algorithm uses the timing information carried by this representation in addressing the stereo-matching problem on moving objects. Using the high temporal resolution of the acquired data stream for the dynamic vision sensor, we show that matching on the timing of the visual events provides a new solution to the real-time computation of 3-D objects when combined with geometric constraints using the distance to the epipolar lines. The proposed algorithm is able to filter out incorrect matches and to accurately reconstruct the depth of moving objects despite the low spatial resolution of the sensor. This brief sets up the principles for further event-based vision processing and demonstrates the importance of dynamic information and spike timing in processing asynchronous streams of visual events.

  9. Blending Online Asynchronous and Synchronous Learning

    Directory of Open Access Journals (Sweden)

    Lisa C. Yamagata-Lynch

    2014-04-01

    Full Text Available In this article I will share a qualitative self-study about a 15-week blended 100% online graduate level course facilitated through synchronous meetings on Blackboard Collaborate and asynchronous discussions on Blackboard. I taught the course at the University of Tennessee (UT during the spring 2012 semester and the course topic was online learning environments. The primary research question of this study was: How can the designer/instructor optimize learning experiences for students who are studying about online learning environments in a blended online course relying on both synchronous and asynchronous technologies? I relied on student reflections of course activities during the beginning, middle, and the end of the semester as the primary data source to obtain their insights regarding course experiences. Through the experiences involved in designing and teaching the course and engaging in this study I found that there is room in the instructional technology research community to address strategies for facilitating online synchronous learning that complement asynchronous learning. Synchronous online whole class meetings and well-structured small group meetings can help students feel a stronger sense of connection to their peers and instructor and stay engaged with course activities. In order to provide meaningful learning spaces in synchronous learning environments, the instructor/designer needs to balance the tension between embracing the flexibility that the online space affords to users and designing deliberate structures that will help them take advantage of the flexible space.

  10. Designing asynchronous circuits using NULL convention logic (NCL)

    CERN Document Server

    Smith, Scott

    2009-01-01

    Designing Asynchronous Circuits using NULL Convention Logic (NCL) begins with an introduction to asynchronous (clockless) logic in general, and then focuses on delay-insensitive asynchronous logic design using the NCL paradigm. The book details design of input-complete and observable dual-rail and quad-rail combinational circuits, and then discusses implementation of sequential circuits, which require datapath feedback. Next, throughput optimization techniques are presented, including pipelining, embedding registration, early completion, and NULL cycle reduction. Subsequently, low-power design

  11. FPGA Architecture for Multi-Style Asynchronous Logic

    CERN Document Server

    Huot, N; Fesquet, L; Renaudin, M

    2011-01-01

    This paper presents a novel FPGA architecture for implementing various styles of asynchronous logic. The main objective is to break the dependency between the FPGA architecture dedicated to asynchronous logic and the logic style. The innovative aspects of the architecture are described. Moreover the structure is well suited to be rebuilt and adapted to fit with further asynchronous logic evolutions thanks to the architecture genericity. A full-adder was implemented in different styles of logic to show the architecture flexibility.

  12. Mathematical Model of Asynchronous Motor with Embedded Combined Braking Device

    Directory of Open Access Journals (Sweden)

    V. Solencov

    2013-01-01

    Full Text Available The paper presents a conclusion of a mathematical model pertaining to asynchronous motor with embedded combined braking device on the basis of electromechanical brake and electromagnetic slip coupling. The mathematical model has been obtained in an orthogonal coordinate system a, b, which is fixed with respect to the asymmetric part of the asynchronous motor with embedded combined braking device. The model makes it possible to investigate transient processes in various asynchronous motors with embedded braking devices.

  13. Toward single cell traction microscopy within 3D collagen matrices

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Matthew S. [Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853 (United States); Long, Rong [Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada T6G 2G8 (Canada); Feng, Xinzeng [Department of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853 (United States); Huang, YuLing [Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853 (United States); Hui, Chung-Yuen [Department of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853 (United States); Wu, Mingming, E-mail: mw272@cornell.edu [Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853 (United States)

    2013-10-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion, and migration. Cells require the three-dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, current understanding of cell–ECM and cell–cell mechanical interactions is largely derived from 2D cell traction force microscopy, in which cells are cultured on a flat substrate. 3D cell traction microscopy is emerging for mapping traction fields of single animal cells embedded in either synthetic or natively derived fibrous gels. We discuss here the development of 3D cell traction microscopy, its current limitations, and perspectives on the future of this technology. Emphasis is placed on strategies for applying 3D cell traction microscopy to individual tumor cell migration within collagen gels. - Highlights: • Review of the current state of the art in 3D cell traction force microscopy. • Bulk and micro-characterization of remodelable fibrous collagen gels. • Strategies for performing 3D cell traction microscopy within collagen gels.

  14. Loads in the lumbar spine during traction therapy.

    Science.gov (United States)

    Lee, R Y; Evans, J H

    2001-01-01

    The purpose of the present study was to determine the loads acting on the lumbar spine when traction therapy was given in the Fowler's position. The study had two parts: a theoretical analysis which showed that traction produced a flexion moment on the spine as well as axial distraction; and an experimental study which measured the flexion moment induced by the adoption of the Fowler's position. The Fowler's position is clinically essential in that it flexes the spine and takes up the slack of the posterior tissues before the traction force is applied. Hence the axial tension and flexion moment generated by the traction force are more effective in stretching the posterior tissues. The angle of pull on the traction harness influences the friction between the body and the couch. However, this consideration is not necessary if a split traction table is used. The mechanical effects of traction are compared with those produced by postero-anterior mobilisation. The relative magnitude and direction of loads produced, and their variation with segmental level should be considered by therapists when choosing a technique for treating low back pain.

  15. EPOS for Coordination of Asynchronous Sensor Webs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop, integrate, and deploy software-based tools to coordinate asynchronous, distributed missions and optimize observation planning spanning simultaneous...

  16. Cascade Control Solution for Traction Motor for Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Zsuzsa Preitl

    2007-10-01

    Full Text Available In this paper a hybrid electric vehicle is considered, which contains both aninternal combustion engine and an electric motor (EM. Without focusing on the othercomponents of the vehicle, the EM is treated in detail, both regarding modelling aspectsand control solutions.After a brief modelling of the plant, two cascade speed control solutions are presented: firsta classical PI+PI cascade control solution is presented. The control systems related totraction electric motors (used in vehicle traction must be able to cope with differentrequests, such as variation of the reference signal, load disturbances which depend on thetransport conditions and parametric disturbances regarding changes in the total mass ofthe vehicle. For this purpose, in the design of the speed controller (external loop a specificmethodology based on extension of the symmetrical optimum method is presented. Thecontrollers are developed using the Modulus–Optimum method for the inner loop, and theExtended Symmetrical Optimum Method, corrected based on the 2p-SO-method, for theouter loop (for a more efficient disturbance rejection.In order to force the behaviour of the system regarding the reference input, a correctionterm is introduced as a non-homogenous structured PI controller solution.Simulations were performed using numerical values taken from a real applicationconsisting in a hybrid vehicle prototype, showing satisfactory behaviour.

  17. Cervical traction. A comparison of sitting and supine positions.

    Science.gov (United States)

    Deets, D; Hands, K L; Hopp, S S

    1977-03-01

    Eight students were studied todetermine the position which provided the greatest amount of posterior intervertebral separation during a cervical traction treatment. A standard angle of 45 degrees with traction apparatus set at zero, 14 Kg (30 pounds), and 18 Kg (40 pounds) were used in both sitting and supine positions. Measurements of posterior intervertebral separation taken from lateral roentgenograms of the C4-C7 vertebrae revealed greater separation in the supine positions. The results suggested that the supine position was more beneficial in treatment of the cervical spine with traction. The investigators concluded that the increased separation in the supine position was related to the patient's increased comfort and relaxation.

  18. Inverse extraction of interfacial tractions from elastic and elasto-plastic far-fields by nonlinear field projection

    Science.gov (United States)

    Chew, Huck Beng

    2013-01-01

    Determining the tractions along a surface or interface from measurement data in the far-fields of nonlinear materials is a challenging inverse problem which has significant engineering and nanoscience applications. Previously, a field projection method was established to identify the crack-tip cohesive zone constitutive relations in an isotropic elastic solid (Hong and Kim, 2003. J. Mech. Phys. Solids 51, 1267). In this paper, the field projection method is further generalized to extracting the tractions along interfaces bounded by nonlinear materials, both with and without pre-existing cracks. The new formulation is based on Maxwell-Betti's reciprocal theorem with a reciprocity gap associated with nonlinear materials. We express the unknown normal and shear tractions along the interface in terms of the Fourier series, and use specially constructed analytical auxiliary fields in the reciprocal theorem to extract the unknown Fourier coefficients from far-field data; the reciprocity gap in the formulation is iteratively determined with a set of numerical algorithms. Our detailed numerical experiments demonstrate that this nonlinear field projection method (NFPM) is well-suited for extracting the interfacial tractions from the far-field data of any nonlinear elastic or elasto-plastic material with known constitutive laws. Applications of the NFPM to experiments and atomistic simulations are discussed.

  19. 21 CFR 888.5890 - Noninvasive traction component.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5890 Noninvasive traction component. (a... apparatus so that a therapeutic pulling force may be applied to the patient's body. (b)...

  20. INTELLIGENT DIAGNOSTIC SYSTEM OF EMERGENCY SITUATIONS IN TRACTION SUBSTATIONS DC

    Directory of Open Access Journals (Sweden)

    Sh. N. Nasyrov

    2009-09-01

    Full Text Available In the article the architecture and algorithm of operating an expert system providing the efficiency of functioning the electric equipment for traction substation as well as the four-parameter belonging function are determined.

  1. Intravitreal injection of perfluoropropane for the treatment of vitreomacular traction

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Wan

    2013-07-01

    Full Text Available AIM: To study the efficacy of a single intravitreal injection of perfluoropropane(C3F8in releasing vitreomacular traction. METHODS: Twelve eyes of 12 consecutive patients with vitreomacular traction received a single intravitreal injection of 0.3mL 100%(C3F8were retrospectively analyzed. The best corrected vision acuity and the neural epithelium thickness of central macular were observed. RESULTS: One month following treatment, vitreomacular traction was released in 5 eyes(42%, mean final visual acuity(VAimproved 0.04 and mean central foveal thickness decreased by 69μm. The vision acuity before and after treatment were 0.20±0.07, 0.25±0.04 respectively.CONCLUSION: Intravitreal C3F8 injection could offer a minimally invasive alternative to pars plana vitrectomy in patients with vitreomacular traction.

  2. Mechanical Lumbar Traction: What Is Its Place in Clinical Practice?

    Science.gov (United States)

    2016-03-01

    Summary evidence concludes that mechanical lumbar traction is not effective for treating acute or chronic nonspecific low back pain (LBP). However, many physical therapists continue to use it, primarily as an additional modality. Indeed, expert clinical opinion, theoretical models, and some research evidence suggest that certain patients with LBP respond positively to traction. A study published in the March 2016 issue of JOSPT investigates the effectiveness of traction in prone as an adjunct to an extension-oriented exercise program in patients with LBP and leg pain and explores whether a previously identified set of patient characteristics is associated with better outcomes from traction. In this Perspectives for Practice, the authors explain the impact of their findings for clinicians treating these patients.

  3. Traction Force Microscopy in 3-Dimensional Extracellular Matrix Networks.

    Science.gov (United States)

    Cóndor, M; Steinwachs, J; Mark, C; García-Aznar, J M; Fabry, B

    2017-06-19

    Cell migration through a three-dimensional (3-D) matrix depends strongly on the ability of cells to generate traction forces. To overcome the steric hindrance of the matrix, cells need to generate sufficiently high traction forces but also need to distribute these forces spatially in a migration-promoting way. This unit describes a protocol to measure spatial maps of cell traction forces in 3-D biopolymer networks such as collagen, fibrin, or Matrigel. Traction forces are computed from the relationship between measured force-induced matrix deformations surrounding the cell and the known mechanical properties of the matrix. The method does not rely on knowledge of the cell surface coordinates and takes nonlinear mechanical properties of the matrix into account. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. Parallel Distribution of Asynchronous Optical Signals

    CERN Document Server

    White, R J; Bradbury, S M; Marshall, P

    2007-01-01

    An eleven channel digital asynchronous transceiver (DAT) employing parallel optical link technology has been developed for trigger signal distribution across the Very Energetic Radiation Imaging Telescope Array System (VERITAS). Combinatorial logic functions are implemented in Xilinx Spartan 3 FPGAs, providing a versatile solution adaptable for use in future atmospheric Cerenkov detectors and other high-energy astroparticle experiments. The device is dead-time free and introduces a minimal skew of 1.6 ns between channels. The jitter on each DAT channel is less than 0.8 ns 95% of the time, allowing communication between telescopes and a central trigger system separated by hundreds of meters, without limiting array performance.

  5. Globally coupled maps with asynchronous updating

    CERN Document Server

    Abramson, G; Abramson, Guillermo; Zanette, Damian H.

    1998-01-01

    We analyze a system of globally coupled logistic maps with asynchronous updating. We show that its dynamics differs considerably from that of the synchronous case. For growing values of the coupling intensity, an inverse bifurcation cascade replaces the structure of clusters and ordering in the phase diagram. We present numerical simulations and an analytical description based on an effective single-element dynamics affected by internal fluctuations. Both of them show how global coupling is able to suppress the complexity of the single-element evolution. We find that, in contrast to systems with synchronous update, internal fluctuations satisfy the law of large numbers.

  6. Asynchronous Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-02-28

    We present in a unifying way the main components of three examples of asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel event-driven algorithm for Direct Simulation Monte Carlo (DSMC). Finally, we describe how to combine MD with DSMC in an event-driven framework, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  7. Asynchronous Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-08-30

    We present, in a unifying way, the main components of three asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel stochastic molecular-dynamics algorithm that builds on the Direct Simulation Monte Carlo (DSMC). We explain how to effectively combine event-driven and classical time-driven handling, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  8. Two Studies Examining Argumentation in Asynchronous Computer Mediated Communication

    Science.gov (United States)

    Joiner, Richard; Jones, Sarah; Doherty, John

    2008-01-01

    Asynchronous computer mediated communication (CMC) would seem to be an ideal medium for supporting development in student argumentation. This paper investigates this assumption through two studies. The first study compared asynchronous CMC with face-to-face discussions. The transactional and strategic level of the argumentation (i.e. measures of…

  9. Designing Asynchronous Circuits for Low Power: An IFIR Filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1999-01-01

    by numerically small samples). Apart from the improved RAM design, these measures are only viable in an asynchronous design. The principles and techniques explained in this paper are of a general nature, and they apply to the design of asynchronous low-power digital signal-processing circuits in a broader...

  10. ASYNCHRONOUS BYZANTINE AGREEMENT PROTOCOL BASED ON VERIFIABLE SIGNATURE SHARING

    Institute of Scientific and Technical Information of China (English)

    Ji Dongyao; Feng Dengguo

    2006-01-01

    An ([n / 3]- 1 )-resilient Asynchronous Byzantine Agreement Protocol (ABAP) that combines verifiable signature sharing and random secret sharing is proposed. The protocol works in the asynchronous network environment and produces Byzantine agreement within a fixed expected number of computational rounds. The correctness of the protocol is proved in theory.

  11. Asynchronous Learning Sources in a High-Tech Organization

    Science.gov (United States)

    Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

    2009-01-01

    Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

  12. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  13. Factors influencing the determination of cell traction forces.

    Science.gov (United States)

    Zündel, Manuel; Ehret, Alexander E; Mazza, Edoardo

    2017-01-01

    Methods summarized by the term Traction Force Microscopy are widely used to quantify cellular forces in mechanobiological studies. These methods are inverse, in the sense that forces must be determined such that they comply with a measured displacement field. This study investigates how several experimental and analytical factors, originating in the realization of the experiments and the procedures for the analysis, affect the determined traction forces. The present results demonstrate that even for very high resolution measurements free of noise, traction forces can be significantly underestimated, while traction peaks are typically overestimated by 50% or more, even in the noise free case. Compared to this errors, which are inherent to the nature of the mechanical problem and its discretization, the effect of ignoring the out-of-plane displacement component, the interpolation scheme used between the discrete measurement points and the disregard of the geometrical non-linearities when using a nearly linear substrate material are less consequential. Nevertheless, a nonlinear elastic substrate, with strain-stiffening response and some degree of compressibility, can substantially improve the robustness of the reconstruction of traction forces over a wide range of magnitudes. This poses the need for a correct mechanical representation of these non-linearities during the traction reconstruction and a correct mechanical characterization of the substrate itself, especially for the large strain shear domain which is shown to plays a major role in the deformations induced by cells.

  14. Rare-Earth-Free Traction Motor: Rare Earth-Free Traction Motor for Electric Vehicle Applications

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    REACT Project: Baldor will develop a new type of traction motor with the potential to efficiently power future generations of EVs. Unlike today’s large, bulky EV motors which use expensive, imported rare-earth-based magnets, Baldor’s motor could be light, compact, contain no rare earth materials, and have the potential to deliver more torque at a substantially lower cost. Key innovations in this project include the use of a unique motor design, incorporation of an improved cooling system, and the development of advanced materials manufacturing techniques. These innovations could significantly reduce the cost of an electric motor.

  15. Resynchronization of the Asynchronous Polar CD Ind

    Science.gov (United States)

    Myers, Gordon; Patterson, Joseph; de Miguel, Enrique; Hambsch, Franz-Josef; Monard, Berto; Bolt, Greg; McCormick, Jennie; Rea, Robert; Allen, William

    2017-04-01

    CD Ind is one of only four confirmed asynchronous polars (APs). APs are strongly magnetic cataclysmic variables of the AM Herculis subclass with the characteristic that their white dwarfs rotate a few percent out of synchronism with their binary orbit. Theory suggests that nova eruptions disrupt previously synchronized states. Following the eruption, the system is expected to rapidly resynchronize over a timescale of centuries. The other three asynchronous polars—V1432 Aql, BY Cam, and V1500 Cyg—have resynchronization time estimates ranging from 100 to more than 3500 years, with all but one being less than 1200 years. We report on the analysis of over 46,000 observations of CD Ind taken between 2007 and 2016, combined with previous observations from 1996, and estimate a CD Ind resynchronization time of 6400 ± 800 years. We also estimate an orbital period of 110.820(1) minutes and a current (2016.4) white dwarf spin period of 109.6564(1) minutes.

  16. Controllability of asynchronous Boolean multiplex control networks.

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-09-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  17. Asynchronicity of facial blood perfusion in migraine.

    Directory of Open Access Journals (Sweden)

    Nina Zaproudina

    Full Text Available Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  18. Asynchronicity of facial blood perfusion in migraine.

    Science.gov (United States)

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  19. Controllability of asynchronous Boolean multiplex control networks

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-09-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  20. TRACTION RESISTANCE IN CHITOSAN TREATED COTTON

    Directory of Open Access Journals (Sweden)

    LOX Wouter

    2015-05-01

    Full Text Available Nowadays natural products interest has increased. However, when some products are included on textile fibers, they have no affinity and need some binders or other kind of auxiliaries to improve the yeld of the process, and some of them are not so natural as the product which are binding and consequently the “bio” definition is missed as some of them can be considered as highly pollutant. Chitosan is a common used bonding agent for cotton. It improves the antimicrobial and antifungal activity, improves wound healing and is a non-toxic bonding agent. The biopolymer used in this work is chitosan, which is a deacetylated derivative of chitin. These properties depend on the amount of deacetylation (DD and the Molecular weight (MW. Along with these improving properties, as it requires some acid pH to ve solved the treatment with chitosan can have some decreasing mechanical properties. The aim of that paper is to evaluate the change in breaking force of the treated samples and a change in elongation of those samples. It compared different amounts of concentration of chitosan with non treated cotton. The traction resistance test were performed on a dynamometer. The test was conducted according to the UNE EN ISO 13934-1 standard.

  1. Methods of the aerodynamical experiments with simulation of massflow-traction ratio of the power unit

    Science.gov (United States)

    Lokotko, A. V.

    2016-10-01

    Modeling massflow-traction characteristics of the power unit (PU) may be of interest in the study of aerodynamic characteristics (ADC) aircraft models with full dynamic likeness, and in the study of the effect of interference PU. These studies require the use of a number of processing methods. These include: 1) The method of delivery of the high-pressure body of jets model engines on the sensitive part of the aerodynamic balance. 2) The method of estimate accuracy and reliability of measurement thrust generated by the jet device. 3) The method of implementation of the simulator SU in modeling the external contours of the nacelle, and the conditions at the inlet and outlet. 4) The method of determining the traction simulator PU. 5) The method of determining the interference effect from the work of power unit on the ADC of model. 6) The method of producing hot jets of jet engines. The paper examines implemented in ITAM methodology applied to testing in a supersonic wind tunnel T-313.

  2. Advantages of diabetic tractional retinal detachment repair

    Science.gov (United States)

    Sternfeld, Amir; Axer-Siegel, Ruth; Stiebel-Kalish, Hadas; Weinberger, Dov; Ehrlich, Rita

    2015-01-01

    Purpose To evaluate the outcomes and complications of patients with diabetic tractional retinal detachment (TRD) treated with pars plana vitrectomy (PPV). Patients and methods We retrospectively studied a case series of 24 eyes of 21 patients at a single tertiary, university-affiliated medical center. A review was carried out on patients who underwent PPV for the management of TRD due to proliferative diabetic retinopathy from October 2011 to November 2013. Preoperative and final visual outcomes, intraoperative and postoperative complications, and medical background were evaluated. Results A 23 G instrumentation was used in 23 eyes (95.8%), and a 25 G instrumentation in one (4.2%). Mean postoperative follow-up time was 13.3 months (4–30 months). Visual acuity significantly improved from logarithm of the minimum angle of resolution (LogMAR) 1.48 to LogMAR 1.05 (P<0.05). Visual acuity improved by ≥3 lines in 75% of patients. Intraoperative complications included iatrogenic retinal breaks in seven eyes (22.9%) and vitreal hemorrhage in nine eyes (37.5%). In two eyes, one sclerotomy was enlarged to 20 G (8.3%). Postoperative complications included reoperation in five eyes (20.8%) due to persistent subretinal fluid (n=3), vitreous hemorrhage (n=1), and dislocated intraocular lens (n=1). Thirteen patients (54.2%) had postoperative vitreous hemorrhage that cleared spontaneously, five patients (20.8%) required antiglaucoma medications for increased intraocular pressure, seven patients (29.2%) developed an epiretinal membrane, and two patients (8.3%) developed a macular hole. Conclusion Patients with diabetic TRD can benefit from PPV surgery. Intraoperative and postoperative complications can be attributed to the complexity of this disease. PMID:26604667

  3. [Neurogenic bladder caused by spinal cord traction].

    Science.gov (United States)

    Garat, J M; Aragona, F; Martinez, E

    1985-01-01

    A neurogenic bladder was the presenting syndrome in three cases of spinal cord traction. Of the typical symptomatic triad: neuro-orthopedic, cutaneous and urologic, the latter was of primary importance. Symptoms in the first case were incomplete bladder retention with distention of upper urinary tract, right-sided vesicorenal reflux and renal insufficiency. Six months after excision of a sacral lipoma and freeing of the filum terminale, micturition had become normal without residue, and renal function normalized. Right-sided reflux was corrected by submucosal advancement surgery with good results. The clinical history was more suggestive in the second case. Although inaugural symptoms were mictional, there was foot paralysis and a retrosacral lipoma above an abnormal hairy tuft in the upper part of the gluteal cleft. Operation revealed the presence of a dermoid cyst and a lipoma. Their excision combined with section of the filum terminale allowing ascension of the medullary cone. Marked clinical and urodynamic improvement was obtained with normal micturition and disappearance of incontinence. An anti-reflux operation suppressed residual reflux with good urographic results. Marked improvement in mictional disorders was obtained also in the 3rd case after excision of a sacral extradural lipoma and section of the filum terminale, allowing objective ascension of the medullary cone by 4 cm. A very detailed analysis was conducted of similar cases reported in the literature, about 2% of neurogenic bladders in children being affected. The importance of early diagnosis is emphasized as well as the essential need to establish a precise diagnosis of the lipoma of cauda equina and of medullary fixation. Early neurosurgery is justified by the high frequency of improvement in cases treated in this way.

  4. Pneumatic release of focal vitreomacular traction.

    Science.gov (United States)

    Claus, M G; Feron, E; Veckeneer, M

    2017-03-01

    PurposeTo study the efficacy of a single intravitreal injection of expansile gas as a valuable alternative to current treatment options (conservative, pharmacological, and surgical) in patients with symptomatic, focal vitreomacular traction (VMT).Patients and methodsThis study comprises a retrospective, interventional case series of patients. Twenty eyes in seventeen patients with symptomatic and persisting focal VMT were treated in an outpatient setting with an intravitreal gas injection of 0.2 ml. In 19 eyes, 100% hexafluoroethane (C2F6) was used. One eye received sulfur hexafluoride (SF6). To all but three patients posturing advice was given. Patients were reviewed with a full-eye examination and ocular coherence tomography (OCT) after 14 days and later. The primary outcome measure was the release of VMT on OCT.ResultsIn 17 of the 20 (85.0%) treated eyes, a release of VMT was achieved as documented on OCT. The release of VMT was diagnosed during the first month after injection in 11 eyes of 11 patients and within 3 months in 16 eyes of 15 patients. In all but five of our patients, best corrected visual acuity (BCVA) remained stable or improved. In four patients, the progression or development of cataract was the probable cause of the decrease in BCVA. One patient developed a stage II macular hole after injection and needed vitrectomy. None of the treated patients developed retinal breaks.ConclusionIntravitreal expansile gas injection could offer a minimally invasive, low-cost alternative treatment in patients with symptomatic, persisting VMT. Additional studies on a larger number of patients are required.

  5. The Simulation of the Traction Drive with Middle-Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Miroslav Los

    2008-01-01

    Full Text Available This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50Hz traction transformer. The special traction drive topology for AC power systems consists of input high voltage trolley converter (single phase matrix converter –middle frequency transformer - output converter - traction motor has been described. The main attention has been given tothe control algorithm of the traction topology (inserting of NULL vector of matrix converter and Two-value control ofsecondary active rectifier.

  6. A Block-Asynchronous Relaxation Method for Graphics Processing Units

    Energy Technology Data Exchange (ETDEWEB)

    Antz, Hartwig [Karlsruhe Inst. of Technology (KIT) (Germany); Tomov, Stanimire [Univ. of Tennessee, Knoxville, TN (United States); Dongarra, Jack [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Manchester (United Kingdom); Heuveline, Vincent [Karlsruhe Inst. of Technology (KIT) (Germany)

    2011-11-30

    In this paper, we analyze the potential of asynchronous relaxation methods on Graphics Processing Units (GPUs). For this purpose, we developed a set of asynchronous iteration algorithms in CUDA and compared them with a parallel implementation of synchronous relaxation methods on CPU-based systems. For a set of test matrices taken from the University of Florida Matrix Collection we monitor the convergence behavior, the average iteration time and the total time-to-solution time. Analyzing the results, we observe that even for our most basic asynchronous relaxation scheme, despite its lower convergence rate compared to the Gauss-Seidel relaxation (that we expected), the asynchronous iteration running on GPUs is still able to provide solution approximations of certain accuracy in considerably shorter time then Gauss- Seidel running on CPUs. Hence, it overcompensates for the slower convergence by exploiting the scalability and the good fit of the asynchronous schemes for the highly parallel GPU architectures. Further, enhancing the most basic asynchronous approach with hybrid schemes – using multiple iterations within the ”subdomain” handled by a GPU thread block and Jacobi-like asynchronous updates across the ”boundaries”, subject to tuning various parameters – we manage to not only recover the loss of global convergence but often accelerate convergence of up to two times (compared to the effective but difficult to parallelize Gauss-Seidel type of schemes), while keeping the execution time of a global iteration practically the same. This shows the high potential of the asynchronous methods not only as a stand alone numerical solver for linear systems of equations fulfilling certain convergence conditions but more importantly as a smoother in multigrid methods. Due to the explosion of parallelism in todays architecture designs, the significance and the need for asynchronous methods, as the ones described in this work, is expected to grow.

  7. Commande adaptive d'une machine asynchrone

    OpenAIRE

    I. Slama-Belkhodja; De Fornel, B.

    1996-01-01

    Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation e...

  8. Asynchronous discrete event schemes for PDEs

    Science.gov (United States)

    Stone, D.; Geiger, S.; Lord, G. J.

    2017-08-01

    A new class of asynchronous discrete-event simulation schemes for advection-diffusion-reaction equations is introduced, based on the principle of allowing quanta of mass to pass through faces of a (regular, structured) Cartesian finite volume grid. The timescales of these events are linked to the flux on the face. The resulting schemes are self-adaptive, and local in both time and space. Experiments are performed on realistic physical systems related to porous media flow applications, including a large 3D advection diffusion equation and advection diffusion reaction systems. The results are compared to highly accurate reference solutions where the temporal evolution is computed with exponential integrator schemes using the same finite volume discretisation. This allows a reliable estimation of the solution error. Our results indicate a first order convergence of the error as a control parameter is decreased, and we outline a framework for analysis.

  9. Implementation of Universal Asynchronous Receiver and Transmitter

    Directory of Open Access Journals (Sweden)

    Payata Srikanth Yadav

    2015-03-01

    Full Text Available Universal Asynchronous Receiver Transmitter (UART is the serial communication protocol that is used for data exchange between computer & peripherals. UART is a low velocity, short-distance, low-cost protocol. UART includes three modules which are received, the baud rate generator and transmitter. The UART design with Very High Description Language can be integrated into the Field Programmable Gate Array to achieve stable data transmission and to make system reliable and compact. In the result and simulation part, this project will focus on check the receive data with error free & baud rate generation at different frequencies. Before synthesizing of UART a baud rate generator is incorporated into the system. We use the frequency divider which sets itself to required frequency for the functionality at lower frequency. All modules are designed using VERILOG and implemented on Xilinx Suite development board.

  10. Asynchronous Parallel Evolutionary Algorithms for Constrained Optimizations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Recently Guo Tao proposed a stochastic search algorithm in his PhD thesis for solving function op-timization problems. He combined the subspace search method (a general multi-parent recombination strategy) with the population hill-climbing method. The former keeps a global search for overall situation,and the latter keeps the convergence of the algorithm. Guo's algorithm has many advantages ,such as the sim-plicity of its structure ,the higher accuracy of its results, the wide range of its applications ,and the robustness of its use. In this paper a preliminary theoretical analysis of the algorithm is given and some numerical experiments has been done by using Guo's algorithm for demonstrating the theoretical results. Three asynchronous paral-lel evolutionary algorithms with different granularities for MIMD machines are designed by parallelizing Guo's Algorithm.

  11. Trunk muscle response to various protocols of lumbar traction.

    Science.gov (United States)

    Cholewicki, Jacek; Lee, Angela S; Reeves, N Peter; Calle, Elizabeth A

    2009-10-01

    The purpose of this study was to compare trunk muscle activity, spinal decompression force, and trunk flexibility resulting from various protocols of spinal traction. Four experiments explored the effects of (1) sinusoidal, triangular, square, and continuous distraction-force waveforms, (2) 0, 10, 20, and 30 degrees of pull angle, (3) superimposed low, medium and high frequency force oscillations, and (4) sham traction. Nineteen healthy subjects volunteered for this study. Surface EMG was recorded during traction and later used in a biomechanical model to estimate spine decompression force. Trunk flexibility was measured before and after each treatment. There were no differences in muscle activity between any of the experimental conditions except the thoracic erector spinae muscle, which had lower EMG during continuous compared to sinusoidal distraction-force waveform (p=0.02). Thoracic and lumbar erector spinae muscles were significantly less active during sham than real traction (p=0.01 and p=0.04, respectively). The estimated L4-L5 spine compression force was 25N. Trunk flexibility decreased after each experimental session (p=0.01), and there were no differences between sessions. Our results suggest that the trunk muscle activity is minimal and point toward fluid exchange in the disc as one of the key biomechanical effects of spinal traction.

  12. Traction reveals mechanisms of wall effects for microswimmers near boundaries

    Science.gov (United States)

    Shen, Xinhui; Marcos, Fu, Henry C.

    2017-03-01

    The influence of a plane boundary on low-Reynolds-number swimmers has frequently been studied using image systems for flow singularities. However, the boundary effect can also be expressed using a boundary integral representation over the traction on the boundary. We show that examining the traction pattern on the boundary caused by a swimmer can yield physical insights into determining when far-field multipole models are accurate. We investigate the swimming velocities and the traction of a three-sphere swimmer initially placed parallel to an infinite planar wall. In the far field, the instantaneous effect of the wall on the swimmer is well approximated by that of a multipole expansion consisting of a force dipole and a force quadrupole. On the other hand, the swimmer close to the wall must be described by a system of singularities reflecting its internal structure. We show that these limits and the transition between them can be independently identified by examining the traction pattern on the wall, either using a quantitative correlation coefficient or by visual inspection. Last, we find that for nonconstant propulsion, correlations between swimming stroke motions and internal positions are important and not captured by time-averaged traction on the wall, indicating that care must be taken when applying multipole expansions to study boundary effects in cases of nonconstant propulsion.

  13. Maximum Safety Regenerative Power Tracking for DC Traction Power Systems

    Directory of Open Access Journals (Sweden)

    Guifu Du

    2017-02-01

    Full Text Available Direct current (DC traction power systems are widely used in metro transport systems, with running rails usually being used as return conductors. When traction current flows through the running rails, a potential voltage known as “rail potential” is generated between the rails and ground. Currently, abnormal rises of rail potential exist in many railway lines during the operation of railway systems. Excessively high rail potentials pose a threat to human life and to devices connected to the rails. In this paper, the effect of regenerative power distribution on rail potential is analyzed. Maximum safety regenerative power tracking is proposed for the control of maximum absolute rail potential and energy consumption during the operation of DC traction power systems. The dwell time of multiple trains at each station and the trigger voltage of the regenerative energy absorbing device (READ are optimized based on an improved particle swarm optimization (PSO algorithm to manage the distribution of regenerative power. In this way, the maximum absolute rail potential and energy consumption of DC traction power systems can be reduced. The operation data of Guangzhou Metro Line 2 are used in the simulations, and the results show that the scheme can reduce the maximum absolute rail potential and energy consumption effectively and guarantee the safety in energy saving of DC traction power systems.

  14. Cellular Traction Stresses Mediate Extracellular Matrix Degradation by Invadopodia

    Science.gov (United States)

    Jerrell, Rachel J.; Parekh, Aron

    2014-01-01

    During tumorigenesis, matrix rigidity can drive oncogenic transformation via altered cellular proliferation and migration. Cells sense extracellular matrix (ECM) mechanical properties with intracellular tensile forces generated by actomyosin contractility. These contractile forces are transmitted to the matrix surface as traction stresses which mediate mechanical interactions with the ECM. Matrix rigidity has been shown to increase proteolytic ECM degradation by cytoskeletal structures known as invadopodia that are critical for cancer progression suggesting that cellular contractility promotes invasive behavior. However, both increases and decreases in traction stresses have been associated with metastatic behavior. Therefore, the role of cellular contractility in invasive migration leading to metastasis is unclear. To determine the relationship between cellular traction stresses and invadopodia activity, we characterized the invasive and contractile properties of an aggressive carcinoma cell line utilizing polyacrylamide gels of different rigidities. We found that ECM degradation and traction stresses were linear functions of matrix rigidity. Using calyculin A to augment myosin contractility, we also found that traction stresses were strongly predictive of ECM degradation. Overall, our data suggest that cellular force generation may play an important part in invasion and metastasis by mediating invadopodia activity in response to the mechanical properties of the tumor microenvironment. PMID:24412623

  15. Scalable asynchronous execution of cellular automata

    Science.gov (United States)

    Folino, Gianluigi; Giordano, Andrea; Mastroianni, Carlo

    2016-10-01

    The performance and scalability of cellular automata, when executed on parallel/distributed machines, are limited by the necessity of synchronizing all the nodes at each time step, i.e., a node can execute only after the execution of the previous step at all the other nodes. However, these synchronization requirements can be relaxed: a node can execute one step after synchronizing only with the adjacent nodes. In this fashion, different nodes can execute different time steps. This can be a notable advantageous in many novel and increasingly popular applications of cellular automata, such as smart city applications, simulation of natural phenomena, etc., in which the execution times can be different and variable, due to the heterogeneity of machines and/or data and/or executed functions. Indeed, a longer execution time at a node does not slow down the execution at all the other nodes but only at the neighboring nodes. This is particularly advantageous when the nodes that act as bottlenecks vary during the application execution. The goal of the paper is to analyze the benefits that can be achieved with the described asynchronous implementation of cellular automata, when compared to the classical all-to-all synchronization pattern. The performance and scalability have been evaluated through a Petri net model, as this model is very useful to represent the synchronization barrier among nodes. We examined the usual case in which the territory is partitioned into a number of regions, and the computation associated with a region is assigned to a computing node. We considered both the cases of mono-dimensional and two-dimensional partitioning. The results show that the advantage obtained through the asynchronous execution, when compared to the all-to-all synchronous approach is notable, and it can be as large as 90% in terms of speedup.

  16. Evaluating the Efficiency of Asynchronous Systems with FASE

    CERN Document Server

    Buti, Federico; Corradini, Flavio; Di Berardini, Maria Rita; Vogler, Walter

    2011-01-01

    In this paper, we present FASE (Faster Asynchronous Systems Evaluation), a tool for evaluating the worst-case efficiency of asynchronous systems. The tool is based on some well-established results in the setting of a timed process algebra (PAFAS: a Process Algebra for Faster Asynchronous Systems). To show the applicability of FASE to concrete meaningful examples, we consider three implementations of a bounded buffer and use FASE to automatically evaluate their worst-case efficiency. We finally contrast our results with previous ones where the efficiency of the same implementations has already been considered.

  17. New Asynchronous Motor Galvanometer%异步电动机专用电流计

    Institute of Scientific and Technical Information of China (English)

    彭鞍虹; 刘刚; 武传胜

    2001-01-01

    针对异步电动机电流计存在的耐起动电流冲击和指示正常运行电流之间的矛盾,试制了一种新型的异步电动机专用电流计,经测试完全满足工程要求.%A new special galvanometer for asynchronous motor is found, whichresolve the hitting current of motor starting and showing current when motor running. The testing result shows that it can satisfy engineering.

  18. Internal end-effect problem in a linear asynchronous MHD machine with arbitrary current load

    Energy Technology Data Exchange (ETDEWEB)

    Vilnitis, A.Ya.

    1977-01-01

    The internal end-effect problem in a bilateral linear asynchronous engine is solved by variation of constants for a surface current load of any type, including discrete conductors. Mathematically correct formulae for this case are given for computing the mechanical force on wound coils and the active power. Known methods of end-effect compensation are examined. The requirements for the surface load of inductors were found for the case where the requirements may be limited to an internal problem and scattering along the magnetic circuit ends.

  19. Optical Coherence Tomography in Spontaneous Resolution of Vitreomacular Traction Syndrome

    Directory of Open Access Journals (Sweden)

    Kuo-Hsuan Hung

    2010-06-01

    Full Text Available Vitreomacular traction syndrome (VTS is a vitreoretinal interface abnormality. The disorder is caused by incomplete posterior vitreous detachment with persistent traction on the macula that produces symptoms and decreased vision. Most symptomatic eyes with VTS undergo a further decrease in visual acuity. Spontaneous complete vitreomacular separation occurs infrequently in eyes with VTS. Surgical intervention may be considered if severe metamorphopsia and decreased visual quality occur. Herein, we report 2 typical cases of idiopathic VTS with spontaneous resolution of vitreo-retinal traction demonstrated by optical coherence tomography. Optical coherence tomography is a sensitive and useful tool for the confirmation of diagnosis and for the serial anatomical evaluation of patients with VTS.

  20. [The effect of indomethacin suppository in preventing mesenteric traction syndrome].

    Science.gov (United States)

    Koyama, K; Kaneko, I; Mori, K

    1995-08-01

    Mesenteric traction syndrome consists of cutaneous hyperemia with hypotension and tachycardia. NSAIDs could inhibit the phenomenon, but there are few reports about when to administer these drugs. In this study, we evaluated the effect of indomethacin on preventing mesenteric traction syndrome when administered preoperatively and just after induction of anesthesia. Thirty-six patients scheduled for abdominal hysterectomy were studied. Patients were randomized into three groups. Group C (n = 12); control, group T (n = 12); indomethacin 50 mg suppository just after induction of anesthesia, group P (n = 12); indomethacin 50 mg suppository about 90 min before incision. The effect of indomethacin was evaluated from the extent of cutaneous hyperemia. MTS was suppressed in group P, but not in group T (P traction syndrome.

  1. Controlling cell-matrix traction forces by extracellular geometry

    Science.gov (United States)

    Banerjee, Shiladitya; Marchetti, M. Cristina

    2013-03-01

    We present a minimal continuum model of strongly adhering cells as active contractile isotropic media and use the model for studying the effect of the geometry of the adhesion patch in controlling the spatial distribution of traction and cellular stresses. Activity is introduced as a contractile, hence negative, spatially homogeneous contribution to the pressure. The model shows that patterning of adhesion regions can be used to control traction stress distribution and yields several results consistent with experimental observations. Specifically, the cell spread area is found to increase with substrate stiffness and an analytic expression of the dependence is obtained for circular cells. The correlation between the magnitude of traction stresses and cell boundary curvature is also demonstrated and analyzed.

  2. Traction sheave elevator, hoisting unit and machine space

    Science.gov (United States)

    Hakala, Harri; Mustalahti, Jorma; Aulanko, Esko

    2000-01-01

    Traction sheave elevator consisting of an elevator car moving along elevator guide rails, a counterweight moving along counterweight guide rails, a set of hoisting ropes (3) on which the elevator car and counterweight are suspended, and a drive machine unit (6) driving a traction sheave (7) acting on the hoisting ropes (3) and placed in the elevator shaft. The drive machine unit (6) is of a flat construction. A wall of the elevator shaft is provided with a machine space with its open side facing towards the shaft, the essential parts of the drive machine unit (6) being placed in the space. The hoisting unit (9) of the traction sheave elevator consists of a substantially discoidal drive machine unit (6) and an instrument panel (8) mounted on the frame (20) of the hoisting unit.

  3. Advantages of diabetic tractional retinal detachment repair

    Directory of Open Access Journals (Sweden)

    Sternfeld A

    2015-10-01

    Full Text Available Amir Sternfeld, Ruth Axer-Siegel, Hadas Stiebel-Kalish, Dov Weinberger, Rita Ehrlich Department of Ophthalmology, Rabin Medical Center, Beilinson Campus, Petach Tikva, Israel Purpose: To evaluate the outcomes and complications of patients with diabetic tractional retinal detachment (TRD treated with pars plana vitrectomy (PPV.Patients and methods: We retrospectively studied a case series of 24 eyes of 21 patients at a single tertiary, university-affiliated medical center. A review was carried out on patients who underwent PPV for the management of TRD due to proliferative diabetic retinopathy from October 2011 to November 2013. Preoperative and final visual outcomes, intraoperative and postoperative complications, and medical background were evaluated.Results: A 23 G instrumentation was used in 23 eyes (95.8%, and a 25 G instrumentation in one (4.2%. Mean postoperative follow-up time was 13.3 months (4–30 months. Visual acuity significantly improved from logarithm of the minimum angle of resolution (LogMAR 1.48 to LogMAR 1.05 (P<0.05. Visual acuity improved by ≥3 lines in 75% of patients. Intraoperative complications included iatrogenic retinal breaks in seven eyes (22.9% and vitreal hemorrhage in nine eyes (37.5%. In two eyes, one sclerotomy was enlarged to 20 G (8.3%. Postoperative complications included reoperation in five eyes (20.8% due to persistent subretinal fluid (n=3, vitreous hemorrhage (n=1, and dislocated intraocular lens (n=1. Thirteen patients (54.2% had postoperative vitreous hemorrhage that cleared spontaneously, five patients (20.8% required antiglaucoma medications for increased intraocular pressure, seven patients (29.2% developed an epiretinal membrane, and two patients (8.3% developed a macular hole.Conclusion: Patients with diabetic TRD can benefit from PPV surgery. Intraoperative and postoperative complications can be attributed to the complexity of this disease. Keywords: diabetic retinopathy, proliferative

  4. Cell-ECM traction force modulates endogenous tension at cell-cell contacts

    National Research Council Canada - National Science Library

    Venkat Maruthamuthu; Benedikt Sabass; Ulrich S. Schwarz; Margaret L. Gardel; Shu Chien

    2011-01-01

    .... A direct relationship between the total cellular traction force on the ECM and the endogenous cell-cell force exists, indicating that the cell-cell tension is a constant fraction of the cell-ECM traction...

  5. Optimum Multiuser Detector for Multipath Slow Fading Asynchronous CDMA Channels

    Institute of Scientific and Technical Information of China (English)

    WangZhaocheng; YangZhixing; 等

    1995-01-01

    A structure of optimum multiuser detector for asynchronous CDMA in multipath slow fading channels is derived and the significant performance gain over the conventional RAKE receiv-er is shown by simulation.

  6. Stand-Alone and Hybrid Positioning Using Asynchronous Pseudolites

    Directory of Open Access Journals (Sweden)

    Ciro Gioia

    2014-12-01

    Full Text Available global navigation satellite system (GNSS receivers are usually unable to achieve satisfactory performance in difficult environments, such as open-pit mines, urban canyons and indoors. Pseudolites have the potential to extend GNSS usage and significantly improve receiver performance in such environments by providing additional navigation signals. This also applies to asynchronous pseudolite systems, where different pseudolites operate in an independent way. Asynchronous pseudolite systems require, however, dedicated strategies in order to properly integrate GNSS and pseudolite measurements. In this paper, several asynchronous pseudolite/GNSS integration strategies are considered: loosely- and tightly-coupled approaches are developed and combined with pseudolite proximity and receiver signal strength (RSS-based positioning. The performance of the approaches proposed has been tested in different scenarios, including static and kinematic conditions. The tests performed demonstrate that the methods developed are effective techniques for integrating heterogeneous measurements from different sources, such as asynchronous pseudolites and GNSS.

  7. A proof system for asynchronously communicating deterministic processes

    NARCIS (Netherlands)

    de Boer, F.S.|info:eu-repo/dai/nl/072666641; van Hulst, M.

    1994-01-01

    We introduce in this paper new communication and synchronization constructs which allow deterministic processes, communicating asynchronously via unbounded FIFO buffers, to cope with an indeterminate environment. We develop for the resulting parallel programming language, which subsumes deterministi

  8. A proof system for asynchronously communicating deterministic processes

    NARCIS (Netherlands)

    de Boer, F.S.; van Hulst, M.

    1994-01-01

    We introduce in this paper new communication and synchronization constructs which allow deterministic processes, communicating asynchronously via unbounded FIFO buffers, to cope with an indeterminate environment. We develop for the resulting parallel programming language, which subsumes deterministi

  9. Current Trends in High-Level Synthesis of Asynchronous Circuits

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2009-01-01

    This paper is a survey paper presenting what the author sees as two major and promising trends in the current research in CAD-tools and design-methods for asynchronous circuits. One branch of research builds on top of existing asynchronous CAD-tools that perform syntax directed translation, e.......g. the Haste/TiDE tool from Handshake Solutions or the Balsa tool from the University of Manchester. The aims are to add highlevel synthesis capabilities to these tools and to extend the tools such that a wider range of (higher speed) micro-architectures can be generated. Another branch of research takes...... a conventional synchronous circuit as the starting point, and then adds some form of handshake-based flow-control. One approach keeps the global clock and implements discrete-time asynchronous operation. Another approach substitutes the clocked registers by asynchronous handshake-registers, thus creating truly...

  10. Asynchronous Multi-Party Computation with Quadratic Communication

    DEFF Research Database (Denmark)

    Hirt, Martin; Nielsen, Jesper Buus; Przydatek, Bartosz

    2008-01-01

    We present an efficient protocol for secure multi-party computation in the asynchronous model with optimal resilience. For n parties, up to t computed with communication complexity O(cn^2k) bits, which...

  11. Asynchronous Mid-Value Select in Hybrid SAL

    Data.gov (United States)

    National Aeronautics and Space Administration — The following SAL model is an abstraction of a module that implements a fault-tolerant mid-value select on asynchronously produced inputs. This is part of a larger...

  12. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  13. Adhesion energy, surface traction and surface tension in liquid xenon

    Indian Academy of Sciences (India)

    B Mathew; G A Adebayo

    2011-12-01

    We calculated the adhesion energy, the surface traction and the surface energy of liquid xenon using molecular dynamics (MD) simulation. The value of the adhesion energy for liquid xenon at a reduced density of 0.630 was found to be 0.591 J/m2 and the surface traction has a peak at = 3.32 Å. It was observed that the attraction of the molecules in the liquid surface which produces a resistance to penetration decreases with temperature. This may be attributed to the greater average separation of molecules at higher temperature.

  14. Temperature control of power semiconductor devices in traction applications

    Science.gov (United States)

    Pugachev, A. A.; Strekalov, N. N.

    2017-02-01

    The peculiarity of thermal management of traction frequency converters of a railway rolling stock is highlighted. The topology and the operation principle of the automatic temperature control system of power semiconductor modules of the traction frequency converter are designed and discussed. The features of semiconductors as an object of temperature control are considered; the equivalent circuit of thermal processes in the semiconductors is suggested, the power losses in the two-level voltage source inverters are evaluated and analyzed. The dynamic properties and characteristics of the cooling fan induction motor electric drive with the scalar control are presented. The results of simulation in Matlab are shown for the steady state of thermal processes.

  15. THE MEASUREMENT ELECTROMAGNETIC INTERFERENCE IN THE REVERSE TRACTION NETWORK

    Directory of Open Access Journals (Sweden)

    T. M. Serdiuk

    2009-09-01

    Full Text Available The original automated method of measurement of electrical noise in the return electric-traction network is proposed. It is realized on the base of car-laboratory “Automatics, telemechanics and communication”. The mathematic model of return electric-traction network is developed to scientific bases of automated measurement. It allows us obtaining the mathematic expressions for change of voltage and current harmonics in the rail net and taking into account the inhomogeneity of lines for the following analytic determination of a source of electric noise.

  16. Fault Location in Power Electrical Traction Line System

    Directory of Open Access Journals (Sweden)

    Yimin Zhou

    2012-11-01

    Full Text Available In this paper, methods of fault location are discussed in electrical traction single-end direct power supply network systems. Based on the distributed parameter model of the system, the position of the short-circuit fault can be located with the aid of the current and voltage value at the measurement end of the electrical traction line. Furthermore, the influence of the transient resistance, the position of the locomotive, locomotive load for fault location are also discussed. MATLAB simulation tool is used for the simulation experiments. Simulation results are proved the effectiveness of the proposed algorithms.

  17. Dynamics of Traction Stress Field during Cell Division

    Science.gov (United States)

    Tanimoto, Hirokazu; Sano, Masaki

    2012-12-01

    We report a quantitative measurement of traction stress exerted by dividing eukaryotic cells. The stress field was highly dynamic and sequentially changed as follows: (1) strong and localized as two spots, (2) weak and broadly distributed, and (3) strong and localized as four spots. At the final stage of cytokinesis, the dividing cells exerted strong tensile force on the intercellular bridge. The asymmetry of the traction stress and the orientation of the division axis matched throughout the division process, suggesting the possible role of the mechanical force as a “store” of the orientational information.

  18. Novel Asynchronous Wrapper and Its Application to GALS Systems

    Institute of Scientific and Technical Information of China (English)

    Zhuang Shengxian; Peng Anjin; Lars Wanhammar

    2006-01-01

    An asynchronous wrapper with novel handshake circuits for data communication in globally asynchronous locally synchronous (GALS) systems is proposed. The handshake circuits include two communication ports and a local clock generator. Two approaches for the implementation of communication ports are presented, one with pure standard cells and the others with Müller-C elements. The detailed design methodology for GALS systems is given and the circuits are validated with VHDL and circuits simulation in standard CMOS technology.

  19. Substrate Stiffness and Cell Area Predict Cellular Traction Stresses in Single Cells and Cells in Contact

    OpenAIRE

    Califano, Joseph P.; Reinhart-King, Cynthia A.

    2010-01-01

    Cells generate traction stresses against their substrate during adhesion and migration, and traction stresses are used in part by the cell to sense the substrate. While it is clear that traction stresses, substrate stiffness, and cell area are related, it is unclear whether or how area and substrate stiffness affect force generation in cells. Moreover, multiple studies have investigated traction stresses of single cells, but few have focused on forces exerted by cells in contact, which more c...

  20. Stimulation of primary osteoblasts with ATP induces transient vinculin clustering at sites of high intracellular traction force.

    Science.gov (United States)

    Tan, Toh Weng; Pfau, Bastian; Jones, David; Meyer, Thomas

    2014-02-01

    Adenosine 5'-triphosphate (ATP), released in response to mechanical and inflammatory stimuli, induces the dynamic and asynchronous protrusion and subsequent retraction of local membrane structures in osteoblasts. The molecular mechanisms involved in the ligand-stimulated herniation of the plasma membrane are largely unknown, which prompted us to investigate whether the focal-adhesion protein vinculin is engaged in the cytoskeletal alterations that underlie the ATP-induced membrane blebbing. Using time-lapse fluorescence microscopy of primary bovine osteoblast-like cells expressing green fluorescent protein-tagged vinculin, we found that stimulation of cells with 100 μM ATP resulted in the transient and rapid clustering of recombinant vinculin in the cell periphery, starting approximately 100 s after addition of the nucleotide. The ephemeral nature of the vinculin clusters was made evident by the brevity of their mean assembly and disassembly times (66.7 ± 13.3 s and 99.0 ± 6.6 s, respectively). Traction force vector maps demonstrated that the vinculin-rich clusters were localized predominantly at sites of high traction force. Intracellular calcium measurements showed that the ligand-induced increase in [Ca(2+)]i clearly preceded the clustering of vinculin, since [Ca(2+)]i levels returned to normal within 30 s of exposure to ATP, indicating that intracellular calcium transients trigger a cascade of signalling events that ultimately result in the incorporation of vinculin into membrane-associated focal aggregates.

  1. MODIFIED MICROPIPLINE ARCHITECTURE FOR SYNTHESIZABLE ASYNCHRONOUS FIR FILTER DESIGN

    Directory of Open Access Journals (Sweden)

    Basel Halak

    2016-02-01

    Full Text Available The use of asynchronous design approaches to construct digital signal processing (DSP systems is a rapidly growing research area driven by a wide range of emerging energy constrained applications such as wireless sensor network, portable medical devices and brain implants. The asynchronous design techniques allow the construction of systems which are samples driven, which means they only dissipate dynamic energy when there processing data and idle otherwise. This inherent advantage of asynchronous design over conventional synchronous circuits allows them to be energy efficient. However the implementation flow of asynchronous systems is still difficult due to its lack of compatibility with industrystandard synchronous design tools and modelling languages. This paper devises a novel asynchronous design for a finite impulse response (FIR filter, an essential building block of DSP systems, which is synthesizable and suitable for implementation using conventional synchronous systems design flow and tools. The proposed design is based on a modified version of the micropipline architecture and it is constructed using four phase bundled data protocol. A hardware prototype of the proposed filter has been developed on an FPGA, and systematically verified. The results prove correct functionality of the novel design and a superior performance compared to a synchronous FIR implementation. The findings of this work will allow a wider adoption of asynchronous circuits by DSP designers to harness their energy and performance benefits.

  2. 21 CFR 888.5850 - Nonpowered orthopedic traction apparatus and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonpowered orthopedic traction apparatus and... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5850 Nonpowered orthopedic traction apparatus and accessories. (a) Identification. A nonpowered orthopedic traction...

  3. INDICATORS OF QUALITY OF ELECTRIC ENERGY IN THE ELECTRIC TRACTION DC

    Directory of Open Access Journals (Sweden)

    A. V. Petrov

    2010-04-01

    Full Text Available The research results showing an opportunity to use a power quality rating in a system of direct current electric traction on a traction substation input and output are stated. It is demonstrated that these ratings essentially simplify the quality analysis of power coming into traction circuits.

  4. Powers of Traction Rectifier Substation of DC ELectric Railways 3kV

    Directory of Open Access Journals (Sweden)

    Josef Palecek

    2004-01-01

    Full Text Available The article states main principles of dimensioning of traction supply stations DC traction current system. it also provides detailed results of the traction rectifier substation Ostrava-Svinov load measurement. The measured valued are subsequently used for calculation of characteristic coefficients, whitch make it possible to dimension rectifier groups.

  5. Comparison of cervical vertebral separation in the supine and seated positions using home traction units.

    Science.gov (United States)

    Fater, Dennis C W; Kernozek, Thomas W

    2008-01-01

    This study was performed for the purpose of comparing the magnitude of cervical vertebral separation during cervical traction in supine and seated positions using home traction units. A repeated measures design with two within-subject factors (type of traction and time) was used. Seventeen asymptomatic volunteers received cervical traction in seated and supine position. Subjects received 5 minutes of static traction in sitting or supine using a force of 13.6 kg while in 15 degrees of neck flexion. A lateral radiograph of the cervical spine was taken before traction force was applied and after five minutes of static traction. Anterior and posterior distances between the inferior border of C2 and the superior border of C7 were measured by a radiologist. After supine traction there were significant increases (p=0.001) in posterior cervical vertebral separation compared to any changes after seated traction. There were no significant changes in anterior vertebral separation during either supine or seated traction positions (p=0.769). Supine cervical traction may be more effective for increasing posterior vertebral separation than seated cervical traction.

  6. Commande adaptive d'une machine asynchrone

    Science.gov (United States)

    Slama-Belkhodja, I.; de Fornel, B.

    1996-06-01

    The paper deals with an indirect self-tuning speed control for an induction motor supplied by a chopper-filter-inverter system. Input/Output models are identified with the recursive least squares algorithm and the controller adaptation is based on a pole assignement strategy. Emphasis is put on the evaluation of the parameter identification in order to avoid instabilities because of disturbances or insufficient excitations. This is especially of importance when the adaptive control is carried out in closed loop systems and without additional test signals. Simulation results show the improvement of the dynamic responses and the robustness against load variations or parameters variations (rotor resistance, inertia). Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation et de la nature peu riche en excitations des entrées du processus. Différents régimes transitoires ont été simulés pour apprécier l'apport de cette association (MCR-PP) : démarrages et inversion des sens de rotation, à vide et en charges, applications d'échelons de couple résistant, variations paramétriques. Les résultats permettent d'illustrer, tant au niveau des performances que de la robustesse, l'apport d'une telle commande adaptive pour des entraînements électriques avec une machine asynchrone.

  7. Asynchronous Rate Chaos in Spiking Neuronal Circuits

    Science.gov (United States)

    Harish, Omri; Hansel, David

    2015-01-01

    The brain exhibits temporally complex patterns of activity with features similar to those of chaotic systems. Theoretical studies over the last twenty years have described various computational advantages for such regimes in neuronal systems. Nevertheless, it still remains unclear whether chaos requires specific cellular properties or network architectures, or whether it is a generic property of neuronal circuits. We investigate the dynamics of networks of excitatory-inhibitory (EI) spiking neurons with random sparse connectivity operating in the regime of balance of excitation and inhibition. Combining Dynamical Mean-Field Theory with numerical simulations, we show that chaotic, asynchronous firing rate fluctuations emerge generically for sufficiently strong synapses. Two different mechanisms can lead to these chaotic fluctuations. One mechanism relies on slow I-I inhibition which gives rise to slow subthreshold voltage and rate fluctuations. The decorrelation time of these fluctuations is proportional to the time constant of the inhibition. The second mechanism relies on the recurrent E-I-E feedback loop. It requires slow excitation but the inhibition can be fast. In the corresponding dynamical regime all neurons exhibit rate fluctuations on the time scale of the excitation. Another feature of this regime is that the population-averaged firing rate is substantially smaller in the excitatory population than in the inhibitory population. This is not necessarily the case in the I-I mechanism. Finally, we discuss the neurophysiological and computational significance of our results. PMID:26230679

  8. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Leggett, Charles; The ATLAS collaboration

    2016-01-01

    In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

  9. Rapid, generalized adaptation to asynchronous audiovisual speech.

    Science.gov (United States)

    Van der Burg, Erik; Goodbourn, Patrick T

    2015-04-01

    The brain is adaptive. The speed of propagation through air, and of low-level sensory processing, differs markedly between auditory and visual stimuli; yet the brain can adapt to compensate for the resulting cross-modal delays. Studies investigating temporal recalibration to audiovisual speech have used prolonged adaptation procedures, suggesting that adaptation is sluggish. Here, we show that adaptation to asynchronous audiovisual speech occurs rapidly. Participants viewed a brief clip of an actor pronouncing a single syllable. The voice was either advanced or delayed relative to the corresponding lip movements, and participants were asked to make a synchrony judgement. Although we did not use an explicit adaptation procedure, we demonstrate rapid recalibration based on a single audiovisual event. We find that the point of subjective simultaneity on each trial is highly contingent upon the modality order of the preceding trial. We find compelling evidence that rapid recalibration generalizes across different stimuli, and different actors. Finally, we demonstrate that rapid recalibration occurs even when auditory and visual events clearly belong to different actors. These results suggest that rapid temporal recalibration to audiovisual speech is primarily mediated by basic temporal factors, rather than higher-order factors such as perceived simultaneity and source identity.

  10. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Baines, John; The ATLAS collaboration

    2016-01-01

    In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

  11. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    Directory of Open Access Journals (Sweden)

    A. I. Safonov

    2009-01-01

    Full Text Available The paper analyzes factors that determine dynamic loads of mechanical transmission of trolleybus traction driving gear. The paper proposes a methodology for determination of calculative moments of loading transmission elements. Results of the research are analyzed and recommendations on  dynamic reduction of trolleybus transmission are given in the paper. 

  12. Physical and electrocardiographic evaluation of horses used for wagon traction

    Directory of Open Access Journals (Sweden)

    M.M. Bomfim

    Full Text Available ABSTRACT The objective of this research was to evaluate the electrocardiogram (ECG of horses used for wagon traction and to compare the results with the parameters obtained from inactive horses or horses submitted to a training routine. Fifty-six 3-15-year-old healthy horses (22 females and 34 males were divided into three groups: control (without a work routine; N=21, wagon traction (N=25 and athlete (N=10 and submitted to physical examination and ECG (at rest. The rhythm, heart rate (HR, amplitude and duration of ECG waveforms and intervals were obtained from the frontal plane and base-apex leads. Heart score (HS was calculated using the arithmetic mean of QRS duration in LI, LII and LIII. Measurements of ECG waves were smaller in control group, in comparison with wagon traction and athlete groups, suggesting that exercise can change ECG. Similar results were observed in the wagon traction and athlete groups, but the electrophysiological adjustments to exercise were not the same for these groups.

  13. Quality electricity lines of external power systems electric traction DC

    Directory of Open Access Journals (Sweden)

    A.V. Petrov

    2012-08-01

    Full Text Available The results of studies that compare and analyze the numerical values of some key indicators quality electricity in the lines of the external power supply system the electric traction DC. As a supplement are additional and fundamental values of energy losses in them.

  14. Single Cell Traction Microscopy within 3D Collagen Matrices

    Science.gov (United States)

    Wu, Mingming

    2014-03-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion and migration. Cells require the three dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, our current understanding of cell-ECM and cell-cell mechanical interactions is largely derived from 2D traction force microscopy, in which cells are cultured on a flat substrate. It is now clear that what we learn about cellular behavior on a 2D substrate does not always apply to cells embedded within a 3D biomatrix. 3D traction microscopy is emerging for mapping traction fields of single cells embedded in 3D gel, but current methods cannot account for the fibrous and nonlinear properties of collagen gel. In this talk, I will present a forward computation algorithm that we have developed for 3D cell traction measurements within collagen gels. The application of this technology to understanding cancer migration and invasion will be discussed. This work is supported by the National Center for Research Resources (5R21RR025801-03, NIH) and the National Institute of General Medical Sciences (8 R21 GM103388-03,NIH), and the Cornell Center on the Microenvironment & Metastasis.

  15. Modeling cell-matrix traction forces in Keratinocyte colonies

    Science.gov (United States)

    Banerjee, Shiladitya

    2013-03-01

    Crosstalk between cell-cell and cell-matrix adhesions plays an essential role in the mechanical function of tissues. The traction forces exerted by cohesive keratinocyte colonies with strong cell-cell adhesions are mostly concentrated at the colony periphery. In contrast, for weak cadherin-based intercellular adhesions, individual cells in a colony interact with their matrix independently, with a disorganized distribution of traction forces extending throughout the colony. In this talk I will present a minimal physical model of the colony as contractile elastic media linked by springs and coupled to an elastic substrate. The model captures the spatial distribution of traction forces seen in experiments. For cell colonies with strong cell-cell adhesions, the total traction force of the colony measured in experiments is found to scale with the colony's geometrical size. This scaling suggests the emergence of an effective surface tension of magnitude comparable to that measured for non-adherent, three-dimensional cell aggregates. The physical model supports the scaling and indicates that the surface tension may be controlled by acto-myosin contractility. Supported by the NSF through grant DMR-1004789. This work was done in collaboration with Aaron F. Mertz, Eric R. Dufresne and Valerie Horsley (Yale University) and M. Cristina Marchetti (Syracuse University).

  16. High resolution, large deformation 3D traction force microscopy.

    Science.gov (United States)

    Toyjanova, Jennet; Bar-Kochba, Eyal; López-Fagundo, Cristina; Reichner, Jonathan; Hoffman-Kim, Diane; Franck, Christian

    2014-01-01

    Traction Force Microscopy (TFM) is a powerful approach for quantifying cell-material interactions that over the last two decades has contributed significantly to our understanding of cellular mechanosensing and mechanotransduction. In addition, recent advances in three-dimensional (3D) imaging and traction force analysis (3D TFM) have highlighted the significance of the third dimension in influencing various cellular processes. Yet irrespective of dimensionality, almost all TFM approaches have relied on a linear elastic theory framework to calculate cell surface tractions. Here we present a new high resolution 3D TFM algorithm which utilizes a large deformation formulation to quantify cellular displacement fields with unprecedented resolution. The results feature some of the first experimental evidence that cells are indeed capable of exerting large material deformations, which require the formulation of a new theoretical TFM framework to accurately calculate the traction forces. Based on our previous 3D TFM technique, we reformulate our approach to accurately account for large material deformation and quantitatively contrast and compare both linear and large deformation frameworks as a function of the applied cell deformation. Particular attention is paid in estimating the accuracy penalty associated with utilizing a traditional linear elastic approach in the presence of large deformation gradients.

  17. High resolution, large deformation 3D traction force microscopy.

    Directory of Open Access Journals (Sweden)

    Jennet Toyjanova

    Full Text Available Traction Force Microscopy (TFM is a powerful approach for quantifying cell-material interactions that over the last two decades has contributed significantly to our understanding of cellular mechanosensing and mechanotransduction. In addition, recent advances in three-dimensional (3D imaging and traction force analysis (3D TFM have highlighted the significance of the third dimension in influencing various cellular processes. Yet irrespective of dimensionality, almost all TFM approaches have relied on a linear elastic theory framework to calculate cell surface tractions. Here we present a new high resolution 3D TFM algorithm which utilizes a large deformation formulation to quantify cellular displacement fields with unprecedented resolution. The results feature some of the first experimental evidence that cells are indeed capable of exerting large material deformations, which require the formulation of a new theoretical TFM framework to accurately calculate the traction forces. Based on our previous 3D TFM technique, we reformulate our approach to accurately account for large material deformation and quantitatively contrast and compare both linear and large deformation frameworks as a function of the applied cell deformation. Particular attention is paid in estimating the accuracy penalty associated with utilizing a traditional linear elastic approach in the presence of large deformation gradients.

  18. Traction force dynamics predict gap formation in activated endothelium.

    Science.gov (United States)

    Valent, Erik T; van Nieuw Amerongen, Geerten P; van Hinsbergh, Victor W M; Hordijk, Peter L

    2016-09-10

    In many pathological conditions the endothelium becomes activated and dysfunctional, resulting in hyperpermeability and plasma leakage. No specific therapies are available yet to control endothelial barrier function, which is regulated by inter-endothelial junctions and the generation of acto-myosin-based contractile forces in the context of cell-cell and cell-matrix interactions. However, the spatiotemporal distribution and stimulus-induced reorganization of these integral forces remain largely unknown. Traction force microscopy of human endothelial monolayers was used to visualize contractile forces in resting cells and during thrombin-induced hyperpermeability. Simultaneously, information about endothelial monolayer integrity, adherens junctions and cytoskeletal proteins (F-actin) were captured. This revealed a heterogeneous distribution of traction forces, with nuclear areas showing lower and cell-cell junctions higher traction forces than the whole-monolayer average. Moreover, junctional forces were asymmetrically distributed among neighboring cells. Force vector orientation analysis showed a good correlation with the alignment of F-actin and revealed contractile forces in newly formed filopodia and lamellipodia-like protrusions within the monolayer. Finally, unstable areas, showing high force fluctuations within the monolayer were prone to form inter-endothelial gaps upon stimulation with thrombin. To conclude, contractile traction forces are heterogeneously distributed within endothelial monolayers and force instability, rather than force magnitude, predicts the stimulus-induced formation of intercellular gaps. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. THE DYNAMICS AND TRACTION ENERGY METRICS LOCOMOTIVE VL40

    Directory of Open Access Journals (Sweden)

    S. V. Pylypenko

    2008-03-01

    Full Text Available In the article the results of dynamic running and traction-energy tests of the electric locomotive VL40U are presented. In accordance with the test results a conclusion about the suitability of electric locomotive of such a type for operation with trains containing up to 15 passenger coaches inclusive is made.

  20. Structure of retracted tendons after staged repair following continuous traction.

    Science.gov (United States)

    Farshad, Mazda; Gerber, Christian; Snedeker, Jess G; Frauenfelder, Thomas; Meyer, Dominik C

    2011-12-01

    The effect of staged repair involving continuous re-lengthening of the retracted musculotendinous unit after rotator cuff tear is not known. We quantified changes in chronically retracted tendons undergoing no repair or a staged repair involving an initial re-lengthening of the musculotendinous unit by traction in a sheep model of massive rotator cuff tear. Infraspinatus tendons of 12 sheep were released and allowed to retract for 4 months. Repair was performed after the retracted musculotendinous unit had been progressively returned to its original length through continuous traction in 8 sheep (group I). In the other 4 sheep (group II) traction was not successful and the tendons remained retracted. Tendon structure was assessed macroscopically, by MRI, histology, and TEM. Normalized to their contralateral controls, at sacrifice, tendon thickness was unchanged in group I (116%, n.s) and increased in group II (129%, P Retracted musculotendinous units have deteriorated tendons, characterized by increased collagen fiber crimp, and ultrastructural collagen fibril atrophy and disorganization. Continuous traction may arrest and partially restore degenerative changes in retracted tendon. The findings of this study might contribute to new approaches for the treatment of chronic "irreparable" rotator cuff tears.

  1. Apicotomy as Treatment for Failure of Orthodontic Traction

    Directory of Open Access Journals (Sweden)

    Leandro Berni Osório

    2013-01-01

    Full Text Available Objective. The purpose of this study was to present a case report that demonstrated primary failure in a tooth traction that was subsequently treated with apicotomy technique. Case Report. A 10-year-old girl had an impacted upper right canine with increased pericoronal space, which was apparent on a radiographic image. The right maxillary sinus showed an opacity suggesting sinusitis. The presumptive diagnosis was dentigerous cyst associated with maxillary sinus infection. The plan for treatment included treatment of the sinus infection and cystic lesion and orthodontic traction of the canine after surgical exposure and bonding of an orthodontic appliance. The surgical procedure, canine position, root dilaceration, and probably apical ankylosis acted in the primary failure of the orthodontic traction. Surgical apical cut of the displaced teeth was performed, and tooth position in the dental arch was possible, with a positive response to the pulp vitality test. Conclusion. Apicotomy is an effective technique to treat severe canine displacement and primary orthodontic traction failure of palatally displaced canines.

  2. Scalability of Several Asynchronous Many-Task Models for In Situ Statistical Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Pebay, Philippe Pierre [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bennett, Janine Camille [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Kolla, Hemanth [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Borghesi, Giulio [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-05-01

    This report is a sequel to [PB16], in which we provided a first progress report on research and development towards a scalable, asynchronous many-task, in situ statistical analysis engine using the Legion runtime system. This earlier work included a prototype implementation of a proposed solution, using a proxy mini-application as a surrogate for a full-scale scientific simulation code. The first scalability studies were conducted with the above on modestly-sized experimental clusters. In contrast, in the current work we have integrated our in situ analysis engines with a full-size scientific application (S3D, using the Legion-SPMD model), and have conducted nu- merical tests on the largest computational platform currently available for DOE science ap- plications. We also provide details regarding the design and development of a light-weight asynchronous collectives library. We describe how this library is utilized within our SPMD- Legion S3D workflow, and compare the data aggregation technique deployed herein to the approach taken within our previous work.

  3. Multiphoton photochemical crosslinking-based fabrication of protein micropatterns with controllable mechanical properties for single cell traction force measurements

    Science.gov (United States)

    Tong, Ming Hui; Huang, Nan; Zhang, Wei; Zhou, Zhuo Long; Ngan, Alfonso Hing Wan; Du, Yanan; Chan, Barbara Pui

    2016-01-01

    Engineering 3D microstructures with predetermined properties is critical for stem cell niche studies. We have developed a multiphoton femtosecond laser-based 3D printing platform, which generates complex protein microstructures in minutes. Here, we used the platform to test a series of fabrication and reagent parameters in precisely controlling the mechanical properties of protein micropillars. Atomic force microscopy was utilized to measure the reduced elastic modulus of the micropillars, and transmission electron microscopy was used to visualize the porosity of the structures. The reduced elastic modulus of the micropillars associated positively and linearly with the scanning power. On the other hand, the porosity and pore size of the micropillars associated inversely and linearly with the scanning power and reagent concentrations. While keeping the elastic modulus constant, the stiffness of the micropillars was controlled by varying their height. Subsequently, the single cell traction forces of rabbit chondrocytes, human dermal fibroblasts, human mesenchymal stem cells, and bovine nucleus pulposus cells (bNPCs) were successfully measured by culturing the cells on micropillar arrays of different stiffness. Our results showed that the traction forces of all groups showed positive relationship with stiffness, and that the chondrocytes and bNPCs generated the highest and lowest traction forces, respectively.

  4. CURRENT VECTOR CONTROL OF PERMANENT-MAGNET SYNCHRONOUS MOTOR OF HYBRID VEHICLE ENGINE

    Directory of Open Access Journals (Sweden)

    S. Serikov

    2009-01-01

    Full Text Available Characteristics of traction permanent-magnet synchronous motor under current vector optimum control in the possible traction-speed mode area which are relevant for hybrid vehicle engine have been investigated. As a criterion of optimality a maximum of electromagnetic moment per unit of current have been taken.

  5. Full L1-regularized Traction Force Microscopy over whole cells.

    Science.gov (United States)

    Suñé-Auñón, Alejandro; Jorge-Peñas, Alvaro; Aguilar-Cuenca, Rocío; Vicente-Manzanares, Miguel; Van Oosterwyck, Hans; Muñoz-Barrutia, Arrate

    2017-08-10

    Traction Force Microscopy (TFM) is a widespread technique to estimate the tractions that cells exert on the surrounding substrate. To recover the tractions, it is necessary to solve an inverse problem, which is ill-posed and needs regularization to make the solution stable. The typical regularization scheme is given by the minimization of a cost functional, which is divided in two terms: the error present in the data or data fidelity term; and the regularization or penalty term. The classical approach is to use zero-order Tikhonov or L2-regularization, which uses the L2-norm for both terms in the cost function. Recently, some studies have demonstrated an improved performance using L1-regularization (L1-norm in the penalty term) related to an increase in the spatial resolution and sensitivity of the recovered traction field. In this manuscript, we present a comparison between the previous two regularization schemes (relying in the L2-norm for the data fidelity term) and the full L1-regularization (using the L1-norm for both terms in the cost function) for synthetic and real data. Our results reveal that L1-regularizations give an improved spatial resolution (more important for full L1-regularization) and a reduction in the background noise with respect to the classical zero-order Tikhonov regularization. In addition, we present an approximation, which makes feasible the recovery of cellular tractions over whole cells on typical full-size microscope images when working in the spatial domain. The proposed full L1-regularization improves the sensitivity to recover small stress footprints. Moreover, the proposed method has been validated to work on full-field microscopy images of real cells, what certainly demonstrates it is a promising tool for biological applications.

  6. Structural strength analysis and fatigue life prediction of traction converter box in high-speed EMU

    Science.gov (United States)

    Tan, Qin; Li, Qiang

    2017-01-01

    The method of building the FEA model of traction converter box in high-speed EMU and analyzing the static strength and fatigue strength of traction converter box based on IEC 61373-2010 and EN 12663 standards is presented in this paper. The load-stress correlation coefficients of weak points is obtained by FEA model, applied to transfer the load history of traction converter box to stress history of each point. The fatigue damage is calculated based on Miner's rule and the fatigue life of traction converter box is predicted. According to study, the structural strength of traction converter box meets design requirements.

  7. ASCERTAINMENT OF THE EQUIVALENT CIRCUIT PARAMETERS OF THE ASYNCHRONOUS MACHINE

    Directory of Open Access Journals (Sweden)

    V. S. Safaryan

    2015-01-01

    Full Text Available The article considers experimental and analytical determination of the asynchronous machine equivalent-circuit parameters with application of the reference data. Transient processes investigation of the asynchronous machines necessitates the equivalent circuit parameters (resistance impedance, inductances and coefficient of the stator-rotor contours mutual inductance that help form the transitory-process mathematical simulation model. The reference books do not provide those parameters; they instead give the rated ones (active power, voltage, slide, coefficient of performance and capacity coefficient as well as the ratio of starting and nominal currents and torques. The noted studies on the asynchronous machine equivalent-circuits parametrization fail to solve the problems ad finem or solve them with admissions. The paper presents experimental and analytical determinations of the asynchronous machine equivalent-circuit parameters: the experimental one based on the results of two measurements and the analytical one where the problem boils down to solving a system of nonlineal algebraic equations. The authors investigate the equivalent asynchronous machine input-resistance properties and adduce the dependence curvatures of the input-resistances on the slide. They present a symbolic model for analytical parameterization of the asynchronous machine equivalent-circuit that represents a system of nonlineal equations and requires one of the rotor-parameters arbitrary assignment. The article demonstrates that for the asynchronous machine equivalent-circuit experimental parameterization the measures are to be conducted of the stator-circuit voltage, current and active power with two different slides and arbitrary assignment of one of the rotor parameters. The paper substantiates the fact that additional measurement does not discard the rotor-parameter choice arbitrariness. The authors establish that in motoring mode there is a critical slide by which the

  8. IHadoop: Asynchronous iterations for MapReduce

    KAUST Repository

    Elnikety, Eslam Mohamed Ibrahim

    2011-11-01

    MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  9. Gigabit Ethernet Asynchronous Clock Compensation FIFO

    Science.gov (United States)

    Duhachek, Jeff

    2012-01-01

    Clock compensation for Gigabit Ethernet is necessary because the clock recovered from the 1.25 Gb/s serial data stream has the potential to be 200 ppm slower or faster than the system clock. The serial data is converted to 10-bit parallel data at a 125 MHz rate on a clock recovered from the serial data stream. This recovered data needs to be processed by a system clock that is also running at a nominal rate of 125 MHz, but not synchronous to the recovered clock. To cross clock domains, an asynchronous FIFO (first-in-first-out) is used, with the write pointer (wprt) in the recovered clock domain and the read pointer (rptr) in the system clock domain. Because the clocks are generated from separate sources, there is potential for FIFO overflow or underflow. Clock compensation in Gigabit Ethernet is possible by taking advantage of the protocol data stream features. There are two distinct data streams that occur in Gigabit Ethernet where identical data is transmitted for a period of time. The first is configuration, which happens during auto-negotiation. The second is idle, which occurs at the end of auto-negotiation and between every packet. The identical data in the FIFO can be repeated by decrementing the read pointer, thus compensating for a FIFO that is draining too fast. The identical data in the FIFO can also be skipped by incrementing the read pointer, which compensates for a FIFO draining too slowly. The unique and novel features of this FIFO are that it works in both the idle stream and the configuration streams. The increment or decrement of the read pointer is different in the idle and compensation streams to preserve disparity. Another unique feature is that the read pointer to write pointer difference range changes between compensation and idle to minimize FIFO latency during packet transmission.

  10. Asynchronous reference frame agreement in a quantum network

    Science.gov (United States)

    Islam, Tanvirul; Wehner, Stephanie

    2016-03-01

    An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

  11. DYNAMIC REGIMES OF ASYNCHRONOUS MOTORS WITH CONCATENATED CAPACITORS

    Directory of Open Access Journals (Sweden)

    V. S. Malyar

    2015-04-01

    Full Text Available Purpose. Development of mathematical model for calculation of starting modes of asynchronous motor connected in series with capacitors. Method. Mathematical modeling of dynamic modes of asynchronous motors with lateral capacitor compensation of reactive power. Results. The calculation algorithm and results of mathematic modeling of processes during starting modes of asynchronous motor feeding from the network through capacitors connected in series are presented. It is shown that for some values of capacitance the self-excitation processes and subharmonic oscillations can appear. Scientific novelty. Mathematic modeling and research of processes in asynchronous motor under its feeding through capacitors is carried out for the first time. The calculation algorithm is based on the mathematical model of asynchronous motor with high level of adequacy, which takes into account the magnetic core saturation and the current displacement in limbs of the rotor. Practical implication. Developed mathematical model makes it possible to investigate the possibility of self-excitation modes appearing in condition of their feeding from line with lateral compensation of reactance in order to avoid the negative effects typical for them.

  12. Asynchronous Communication: Capacity Bounds and Suboptimality of Training

    CERN Document Server

    Tchamkerten, Aslan; Wornell, Gregory

    2011-01-01

    Basic limits of asynchronous point-to-point communication over discrete memoryless channels are established. In the system model of interest, the codeword is transmitted over a channel starting at a random time within a prescribed window whose length corresponds to the level of asynchronism in the system. Communication rate is defined as the ratio between the message size and the elapsed time between when transmission commences and when the decoder makes a decision. Upper and lower bounds on the capacity of such systems are established, and are shown to coincide in some nontrivial cases. Additional properties of capacity as a function of the level of asynchronism are also developed. In practice, communication is typically structured according to a training-based architecture, whereby synchronization and communication are implemented separately. We quantify the inherent constraints in this architecture, and analyze its corresponding performance limits. We show that, in general, schemes conforming to this archi...

  13. Systematic traction techniques in minimal-access pediatric cardiac surgery.

    Science.gov (United States)

    Oiwa, Hiroshi; Ishida, Ryoichi; Sudo, Kenichi

    2004-11-01

    Minimal-access pediatric cardiac surgery is now common in the treatment of simple congenital heart defects. However, methods of securing a good, unobstructed view for surgery and the difficulties of working in a deep, narrow field jeopardize safety in surgical procedures, especially for less experienced surgeons have been described. Our systematic, step-by-step traction techniques on the skin, the pericardium, the right atrial appendage, the aortic root, both venae cavae, and the free wall of the right ventricular outflow, using a mechanical retractor and traction sutures, facilitate surgical field exposure and the achievement of safety. As described below, our procedures are simple, allow direct inspection, and assist those working toward technical mastery.

  14. A Loosely Synchronizing Asynchronous Router for TDM-Scheduled NOCs

    DEFF Research Database (Denmark)

    Kotleas, Ioannis; Humphreys, Dean; Sørensen, Rasmus Bo

    2014-01-01

    This paper presents an asynchronous router design for use in time-division-multiplexed (TDM) networks-on-chip. Unlike existing synchronous, mesochronous and asynchronous router designs with similar functionality, the router is able to silently skip over cycles/TDM-slots where no traffic...... is scheduled and hence avoid all switching activity in the idle links and router ports. In this way switching activity is reduced to the minimum possible amount. The fact that this relaxed synchronization is sufficient to implement TDM scheduling represents a contribution at the conceptual level. The idea can...

  15. On the theoretical gap between synchronous and asynchronous MPC protocols

    DEFF Research Database (Denmark)

    Beerliová-Trubíniová, Zuzana; Hirt, Martin; Nielsen, Jesper Buus

    2010-01-01

    that in the cryptographic setting (with setup), the sole reason for it is the distribution of inputs: given an oracle for input distribution, cryptographically-secure asynchronous MPC is possible with the very same condition as synchronous MPC, namely t ..., we show that such an input-distribution oracle can be reduced to an oracle that allows each party to synchronously broadcast one single message. This means that when one single round of synchronous broadcast is available, then asynchronous MPC is possible at the same condition as synchronous MPC...

  16. Design issues in the semantics and scheduling of asynchronous tasks.

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, Stephen L.

    2013-07-01

    The asynchronous task model serves as a useful vehicle for shared memory parallel programming, particularly on multicore and manycore processors. As adoption of model among programmers has increased, support has emerged for the integration of task parallel language constructs into mainstream programming languages, e.g., C and C++. This paper examines some of the design decisions in Cilk and OpenMP concerning semantics and scheduling of asynchronous tasks with the aim of informing the efforts of committees considering language integration, as well as developers of new task parallel languages and libraries.

  17. Asynchronous Broadcast on the Intel SCC using Interrupts

    OpenAIRE

    Petrović, Darko; Shahmirzadi, Omid; Ropars, Thomas; Schiper, André

    2012-01-01

    International audience; This paper focuses on the design of an asynchronous broadcast primitive on the Intel SCC. Our solution is based on OC-Bcast, a state-of-the-art k-ary tree synchronous broadcast algorithm that leverages the parallelism provided by on-chip Remote Memory Accesses to Message Passing Buffers. In the paper, we study the use of parallel inter-core interrupts as a means to implement an efficient asynchronous group communication primitive, and present the userspace library we d...

  18. Asynchronous updating of threshold-coupled chaotic neurons

    Indian Academy of Sciences (India)

    Manish Dev Shirmali; Sudeshna Sinha; Kazuyuki Aihara

    2008-06-01

    We study a network of chaotic model neurons incorporating threshold activated coupling. We obtain a wide range of spatiotemporal patterns under varying degrees of asynchronicity in the evolution of the neuronal components. For instance, we find that sequential updating of threshold-coupled chaotic neurons can yield dynamical switching of the individual neurons between two states. So varying the asynchronicity in the updating scheme can serve as a control mechanism to extract different responses, and this can have possible applications in computation and information processing.

  19. Effect of continuous lumbar traction on the size of herniated disc material in lumbar disc herniation.

    Science.gov (United States)

    Ozturk, Bulent; Gunduz, Osman Hakan; Ozoran, Kursat; Bostanoglu, Sevinc

    2006-05-01

    We investigated the effects of continuous lumbar traction in patients with lumbar disc herniation on clinical findings, and size of the herniated disc measured by computed tomography (CT). In this prospective, randomized, controlled study, 46 patients with lumbar disc herniation were included, and randomized into two groups as the traction group (24 patients), and the control group (22 patients). The traction group was given a physical therapy program and continuous lumbar traction. The control group was given the same physical therapy program without traction, for the same duration of time. Data for the clinical symptoms and signs were collected before and after the treatment together with calculation of a herniation index, from the CT images that showed the size of the herniated disc material. In the traction group, most of the clinical findings significantly improved with treatment. Size of the herniated disc material in CT decreased significantly only in the traction group. In the traction group the herniation index decreased from 276.6+/-129.6 to 212.5+/-84.3 with treatment (p0.05). Patients with greater herniations tended to respond better to traction. In conclusion, lumbar traction is both effective in improving symptoms and clinical findings in patients with lumbar disc herniation and also in decreasing the size of the herniated disc material as measured by CT.

  20. [Acupuncture combined with traction therapy for lumbar disc herniation: a systematic review].

    Science.gov (United States)

    Li, Xiu-zhen; Chen, Hai-yong; Zheng, Xiao; Liu, Nong-yu

    2014-09-01

    To evaluate the efficacy and safety of acupuncture combined with traction therapy for lumbar disc herniation, providing the basis for future research strategies. Randomized control trials. (RCT) of acupuncture combined with traction therapy for lumber disc herniation at home and abroad from 2000 to 2013 were searched, analysis and evaluation of literature and strength of evidence were based on the principles and methods of Evidence-based Medicine. The total effective rate and curative rate were considered as primary outcome measures; pain improvement, quality of life, relapse rate and adverse effects were considered as secondary outcome measures. Seventeen RCTs were identified, Meta-analysis showed that (1) total effective rate and curative rate: acupuncture combined with traction therapy was better than single therapy (acupuncture or traction); (2) pain improvement: acupuncture combined with traction therapy was better than traction therapy; (3) relapse rate: current evidence could not support the conclusion that acupuncture combined with traction therapy was better than traction therapy. Acupuncture combined with traction therapy for lumbar disc herniation was effective. However, the included studies were with high risk of bias, important outcome measures such as quality of life, relapse rate and adverse effects were not found in most of the studies. Current evidence has not yet been able to fully reflect acupuncture combined with traction therapy for lumbar disc herniation is better than single therapy, so more RCTs of higher quality are needed to further confirm its efficacy and safety.

  1. Biomechanical analysis of two-step traction therapy in the lumbar spine.

    Science.gov (United States)

    Park, Won Man; Kim, Kyungsoo; Kim, Yoon Hyuk

    2014-12-01

    Traction therapy is one of the most common conservative treatments for low back pain. However, the effects of traction therapy on lumbar spine biomechanics are not well known. We investigated biomechanical effects of two-step traction therapy, which consists of global axial traction and local decompression, on the lumbar spine using a validated three-dimensional finite element model of the lumbar spine. One-third of body weight was applied on the center of the L1 vertebra toward the superior direction for the first axial traction. Anterior translation of the L4 vertebra was considered as the second local decompression. The lordosis angle between the superior planes of the L1 vertebra and sacrum was 44.6° at baseline, 35.2° with global axial traction, and 46.4° with local decompression. The fibers of annulus fibrosus in the posterior region, and intertransverse and posterior longitudinal ligaments experienced stress primarily during global axial traction, these stresses decreased during local decompression. A combination of global axial traction and local decompression would be helpful for reducing tensile stress on the fibers of the annulus fibrosus and ligaments, and intradiscal pressure in traction therapy. This study could be used to develop a safer and more effective type of traction therapy.

  2. Modern Solutions for Automation of Electrical Traction Power Supply Systems

    Directory of Open Access Journals (Sweden)

    Ana Mihaela Andreica

    2011-09-01

    Full Text Available This paper presents modern solutions for the automation of the electrical traction power supply system used in urban public transport (trams, trolleybuses and subway trains. The monitoring and control of this process uses SCADA distributed architectures, grouped around a central point (dispatcher who controls all field sensors, transmitters and actuators using programmable logical controllers. The presented applications refer to the Bucharest electrical transport infrastructure.

  3. Cellular traction stresses increase with increasing metastatic potential.

    Directory of Open Access Journals (Sweden)

    Casey M Kraning-Rush

    Full Text Available Cancer cells exist in a mechanically and chemically heterogeneous microenvironment which undergoes dynamic changes throughout neoplastic progression. During metastasis, cells from a primary tumor acquire characteristics that enable them to escape from the primary tumor and migrate through the heterogeneous stromal environment to establish secondary tumors. Despite being linked to poor prognosis, there are no direct clinical tests available to diagnose the likelihood of metastasis. Moreover, the physical mechanisms employed by metastatic cancer cells to migrate are poorly understood. Because metastasis of most solid tumors requires cells to exert force to reorganize and navigate through dense stroma, we investigated differences in cellular force generation between metastatic and non-metastatic cells. Using traction force microscopy, we found that in human metastatic breast, prostate and lung cancer cell lines, traction stresses were significantly increased compared to non-metastatic counterparts. This trend was recapitulated in the isogenic MCF10AT series of breast cancer cells. Our data also indicate that increased matrix stiffness and collagen density promote increased traction forces, and that metastatic cells generate higher forces than non-metastatic cells across all matrix properties studied. Additionally, we found that cell spreading for these cell lines has a direct relationship with collagen density, but a biphasic relationship with substrate stiffness, indicating that cell area alone does not dictate the magnitude of traction stress generation. Together, these data suggest that cellular contractile force may play an important role in metastasis, and that the physical properties of the stromal environment may regulate cellular force generation. These findings are critical for understanding the physical mechanisms of metastasis and the role of the extracellular microenvironment in metastatic progression.

  4. REACTIVE POWER DEVICES IN SYSTEMS OF ELECTRIC TRACTION

    Directory of Open Access Journals (Sweden)

    M. O. Kostin

    2010-04-01

    Full Text Available A comparative characteristic of different concepts and expressions for determination of reactive power in the circuits with non-sinusoidal electric values has been given. For the first Ukrainian electric locomotives of DE1 type with the system of DC electric traction, the values of reactive power after Budeany, Fryze, and also the differential, integral and generalized reactive powers have been determined. Some measures on reducing its consumption by the DC electric rolling stock have been suggested.

  5. Features of Traction Transformer Windings Utilised as Inductances

    Directory of Open Access Journals (Sweden)

    Jiri Danzer

    2004-01-01

    Full Text Available The paper analyses features of traction transformer desing. Secondary windings of the transformer are utilized as a choke of an locomotive input filter at DC supplying system. Different ways of connections of the secondary windings coils are compared, reachable inductances are determined and forces affecting the coils are computed. The analysis is performed by FEM method for differend locomotive operating modes including breakdown service.

  6. Viscous erosion with a generalized traction integral equation

    CERN Document Server

    Mitchell, William H

    2016-01-01

    A double-layer integral equation for the surface tractions on a body moving in a viscous fluid is derived, allowing for the incorporation of a background flow and/or the presence of a plane wall. The Lorentz reciprocal theorem is used to link the surface tractions on the body to integrals involving the background velocity and stress fields on an imaginary bounding sphere (or hemisphere for wall-bounded flows). The derivation requires the velocity and stress fields associated with numerous fundamental singularity solutions which we provide for free-space and wall-bounded domains. Two sample applications of the method are discussed: we study the tractions on an ellipsoid moving near a plane wall, which provides a more detailed understanding of the well-studied glancing and reversing trajectories, and we explore a new problem, erosion of bodies by a viscous flow, in which the surface is ablated at a rate proportional to the local viscous shear stress. Simulations and analytical estimates suggest that a spherical...

  7. Traction Forces of Endothelial Cells under Slow Shear Flow

    Science.gov (United States)

    Perrault, Cecile M.; Brugues, Agusti; Bazellieres, Elsa; Ricco, Pierre; Lacroix, Damien; Trepat, Xavier

    2015-01-01

    Endothelial cells are constantly exposed to fluid shear stresses that regulate vascular morphogenesis, homeostasis, and disease. The mechanical responses of endothelial cells to relatively high shear flow such as that characteristic of arterial circulation has been extensively studied. Much less is known about the responses of endothelial cells to slow shear flow such as that characteristic of venous circulation, early angiogenesis, atherosclerosis, intracranial aneurysm, or interstitial flow. Here we used a novel, to our knowledge, microfluidic technique to measure traction forces exerted by confluent vascular endothelial cell monolayers under slow shear flow. We found that cells respond to flow with rapid and pronounced increases in traction forces and cell-cell stresses. These responses are reversible in time and do not involve reorientation of the cell body. Traction maps reveal that local cell responses to slow shear flow are highly heterogeneous in magnitude and sign. Our findings unveil a low-flow regime in which endothelial cell mechanics is acutely responsive to shear stress. PMID:26488643

  8. Traction Force and Tension Fluctuations During Axon Growth

    Directory of Open Access Journals (Sweden)

    Jamison ePolackwich

    2015-10-01

    Full Text Available Actively generated mechanical forces play a central role in axon growthand guidance, but the mechanisms that underly force generation andregulation in growing axons remain poorly understood. We reportmeasurements of the dynamics of traction stresses from growth cones ofactively advancing axons from postnatal rat DRG neurons. By tracking themovement of the growth cone and analyzing the traction stress field froma reference frame that moves with it, we are able to show that there isa clear and consistent average stress field that underlies the complexspatial stresses present at any one time. The average stress field hasstrong maxima on the sides of the growth cone, directed inward towardthe growth cone neck. This pattern represents a contractile stresscontained within the growth cone, and a net force that is balanced bythe axon tension. Using high time-resolution measurements of the growthcone traction stresses, we show that the stress field is composed offluctuating local stress peaks, with a large number peaks that live fora short time, a population of peaks whose lifetime distribution followsan exponential decay, and a small number of very long-lived peaks. Weshow that the high time-resolution data also reveal that the tensionappears to vary randomly over short time scales, roughly consistent withthe lifetime of the stress peaks, suggesting that the tensionfluctuations originate from stochastic adhesion dynamics.

  9. Patterned hydrogels for simplified measurement of cell traction forces.

    Science.gov (United States)

    Polio, Samuel R; Smith, Michael L

    2014-01-01

    To understand mechanobiology, a quantitative understanding of how cells interact mechanically with their environment is needed. Cell mechanics is important to study as they play a role in cell behaviors ranging from cell signaling to epithelial to mesenchymal transition in physiological processes such as development and cancer. To study changes in cell contractile behavior, numerous quantitative measurement techniques have been developed based on the measurement of deformations of a substrate from an initial state. Herein, we present details on a technique we have developed for the measurements of 2D cellular traction forces with the goal of facilitating adaptation of this technique by other investigators. This technique is flexible in that it utilizes well-studied methods for microcontact printing and fabrication of polyacrylamide hydrogels to generate regular arrays of patterns that can be transferred onto the hydrogels. From the deformation of the arrays, an automated algorithm can be used to quantitatively determine the traction forces exerted by the cells onto the adhesion points. The simplicity and flexibility of this technique make it a useful contribution to our toolbox for measurement of cell traction forces. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Microglia mechanics: immune activation alters traction forces and durotaxis

    Science.gov (United States)

    Bollmann, Lars; Koser, David E.; Shahapure, Rajesh; Gautier, Hélène O. B.; Holzapfel, Gerhard A.; Scarcelli, Giuliano; Gather, Malte C.; Ulbricht, Elke; Franze, Kristian

    2015-01-01

    Microglial cells are key players in the primary immune response of the central nervous system. They are highly active and motile cells that chemically and mechanically interact with their environment. While the impact of chemical signaling on microglia function has been studied in much detail, the current understanding of mechanical signaling is very limited. When cultured on compliant substrates, primary microglial cells adapted their spread area, morphology, and actin cytoskeleton to the stiffness of their environment. Traction force microscopy revealed that forces exerted by microglia increase with substrate stiffness until reaching a plateau at a shear modulus of ~5 kPa. When cultured on substrates incorporating stiffness gradients, microglia preferentially migrated toward stiffer regions, a process termed durotaxis. Lipopolysaccharide-induced immune-activation of microglia led to changes in traction forces, increased migration velocities and an amplification of durotaxis. We finally developed a mathematical model connecting traction forces with the durotactic behavior of migrating microglial cells. Our results demonstrate that microglia are susceptible to mechanical signals, which could be important during central nervous system development and pathologies. Stiffness gradients in tissue surrounding neural implants such as electrodes, for example, could mechanically attract microglial cells, thus facilitating foreign body reactions detrimental to electrode functioning. PMID:26441534

  11. Simulation software for CRH2 and CRH3 traction driver systems based on SIMULINK and VC

    Institute of Scientific and Technical Information of China (English)

    Qin-fen LU; Bin WANG; Xiao-yan HUANG; Ji-en MA; You-tong FANG; Jin YU; Wen-ping CAO

    2011-01-01

    Simulation models of traction driver systems were established using SIMULINK,according to the actual structure and parameters of China Railway High-Speed 2 (CRH2) and China Railway High-Speed 3 (CRH3) trains.In these models,the traction motor adopts transient current control and an indirect rotor magnetic field orientation vector control strategy,and the traction converter uses sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) methods.After these models are transformed in VC++ program,and a friendly interface and data processing system are constructed.simulation software is obtained for CRH2 and CRH3 traction driver systems.On this basis,the operational performance of a traction converter was simulated and analyzed at different train speeds and in different conditions.The simulation results can provide a reference for the actual design and production of a traction converter.

  12. Differences in Morphology and Traction Generation of Cell Lines Representing Different Stages of Osteogenesis.

    Science.gov (United States)

    Poellmann, Michael J; Estrada, Jonathan B; Boudou, Thomas; Berent, Zachary T; Franck, Christian; Wagoner Johnson, Amy J

    2015-12-01

    Osteogenesis is the process by which mesenchymal stem cells differentiate to osteoblasts and form bone. The morphology and root mean squared (RMS) traction of four cell types representing different stages of osteogenesis were quantified. Undifferentiated D1, differentiated D1, MC3T3-E1, and MLO-A5 cell types were evaluated using both automated image analysis of cells stained for F-actin and by traction force microscopy (TFM). Undifferentiated mesenchymal stem cell lines were small, spindly, and exerted low traction, while differentiated osteoblasts were large, had multiple processes, and exerted higher traction. Size, shape, and traction all correlated with the differentiation stage. Thus, cell morphology evolved and RMS traction increased with differentiation. The results provide a foundation for further work with these cell lines to study the mechanobiology of bone formation.

  13. A Traction Three-Phase to Single-Phase Cascade Converter Substation in an Advanced Traction Power Supply System

    Directory of Open Access Journals (Sweden)

    Xiaoqiong He

    2015-09-01

    Full Text Available The advanced traction power supply system (ATPSS is a new directional development for traction power supply systems, which can totally remove the neutral sections and effectively promote power quality. However, the existing converters suffer from small substation capacity. In this paper, a new configuration based on a three-level neutral point clamped (3L-NPC three-phase to single-phase cascade converter in a substation is proposed for ATPSS, which can be used to match the capacity of the converter for high voltage and large power applications. The control strategy of the proposed converter is analyzed in depth, and the phase disposition sinusoidal pulse width modulation (PD-SPWM with phase shift carrier SPWM (PSC-SPWM is employed in the inverters. Then, the inductance equalizing circuit is applied for the voltage balance on the DC-link. Besides, a LC filter circuit is designed to eliminate the double line-frequency ripple of DC voltage. Afterwards, a simulation model and an experimental prototype are developed, respectively. The simulation results show that the proposed converter in this paper can not only meet the requirements of voltage and capacity for the traction network, but also improve power quality. Finally, the experimental results verify the correctness and feasibility of the proposed control strategy.

  14. INFLUENCE OF THE TIME OF DISINHIBITION TO TRANSIENTS AND WEAR OF THE FRICTION LININGS IN AN ASYNCHRONOUS MOTOR

    Directory of Open Access Journals (Sweden)

    V. V. Solencov

    2016-01-01

    Full Text Available Time and the stopping distance of the electric drive with frequent starting-and-braking modes that contain embedded asynchronous motor with a recessed combined braking device depend on the moment of an electromagnet disinhibition. At the same time other important criteria are taken into the account, i.e. wear resistance of the brake device and the smoothness of the deceleration of the electric drive. In general such an asynchronous motor contains asynchronous engine with squirrel-cage rotor, electromechanical normally-closed brake, electromagnetical slip clutch and control circuit. The mechanical characteristics of the deceleration of asynchronous motor with recessed combined brake device at different moments of an electromagnet disinhibition are presented. The mathematical model is featured and the transients in such a motor are presented. Formation models for computer research were carried out in the Fortran 2008 programming language. Calculation of the system of differential equations was fulfilled by the Runge – Kutta method. The deceleration of the electromechanical brake at various speeds caused different time values and stopping distances. The plots of stopping distance and the braking time at various moments of an electromagnet disinhibition are demonstrated. The optimum moment of switching on an electromechanical brake, providing small stopping distance and the braking time is the time when the speed wвкл = 0,6–0,8 of the nominal. In this case the acceptable number of brake applications for friction linings (compared with mechanical braking will increase by 1.6–2.8 times. The pilot study confirmed the validity of the obtained mathematical models and discovered patterns.

  15. Asynchronous Session Types – Exceptions and Multiparty Interactions

    DEFF Research Database (Denmark)

    Carbone, Marco; Yoshida, Nobuko; Honda, Kohei

    2009-01-01

    to capture many real scenarios, there are cases where they are not powerful enough for describing and validating interactions involving more complex scenarios. In this note, we shall explore two extensions of session types to interactional exceptions and multiparty session in presence of asynchronous...

  16. Psychological Type and Asynchronous Written Dialogue in Adult Learning

    Science.gov (United States)

    Lin, Lin; Cranton, Patricia; Bridglall, Beatrice

    2005-01-01

    This study explores how adults learn from asynchronous written dialogue through the lens of psychological type preferences. We asked participants to discover their dominant and auxiliary psychological preferences using the Personal Empowerment through Type inventory. Participants then completed an open-ended survey in which they described their…

  17. Reliable interface design for combining asynchronous and synchronous circuits

    Science.gov (United States)

    Josephson, Lueli; Brunvand, Erik L.; Gopalakrishan, Ganesh; Hurdle, John F.

    1993-01-01

    In order to successfully integrate asynchronous and synchronous designs, great care must be taken at the interface between the two types of systems. Synchronizing asynchronous inputs with a free running clock can cause well-known problems with metastability in the synchronization circuits. Stretchable clocks allow a clock cycle to expand dynamically in response to the metastability effects of sampling asynchronous inputs. We use an interface organization where the special circuitry for detecting metastability and for stretching the clock that is delivered to the synchronous part of the system is encapsulated in a Q-flop-based interface. This provides a very convenient method for interfacing mixed systems, as the interface and clock generation circuitry are isolated into one special module, and neither the asynchronous nor the synchronous system need be modified internally to accommodate the interface. This is especially important when standard synchronous components are used as there is no opportunity to modify these parts. We show that this interface module is suitable for most mixed design needs and conclude with an example.

  18. Students' Use of Asynchronous Discussions for Academic Discourse Socialization

    Science.gov (United States)

    Beckett, Gulbahar H.; Amaro-Jimenez, Carla; Beckett, Kelvin S.

    2010-01-01

    Our universities are becoming increasingly diverse at the same time as online asynchronous discussions (OADs) are emerging as the most important forum for computer mediated communication (CMC) in distance education. But there is shortage of studies that explore how graduate students from different ethnic, linguistic and cultural backgrounds use…

  19. Asynchronous rotation scan for synthetic aperture interferometric radiometer

    Institute of Scientific and Technical Information of China (English)

    WU Ji; ZHANG Cheng; LIU Hao; SUN WeiYing

    2009-01-01

    Synthetic aperture interferometric technique has wide applications in optics, radio astronomy and mi-crowave remote sensing areas. With the increasing demands of high resolution imaging observation, a new time-sharing sampling scheme of asynchronous rotation scan is proposed to meet the technical challenge of achieving a large equivalent aperture and overcome the operating barriers of space borne application. This configuration is basically composed by two asynchronously and concentrically ro-tating antenna groups, whose revolving radii and speeds are different. The synthetic aperture system with asynchronous rotation scanning scheme can effectively solve the trade-off problem of system complexity, and greatly simplify the system hardware at the cost of sacrificing a certain time resolution. The basic rules and design methods of asynchronous rotation scan are investigated The Gridding method is introduced to inverse the spiral sampling data for image reconstruction. The potential ap-plications of geostationary orbit (GEO) earth observation and solar polar orbit (SPO) plasma cloud observation are explored with numerical simulations to validate the significance and feasibility of this new imaging configuration.

  20. Asynchronous Assessment in a Large Lecture Marketing Course

    Science.gov (United States)

    Downey, W. Scott; Schetzsle, Stacey

    2012-01-01

    Asynchronous assessment, which includes quizzes or exams online or outside class, offers marketing educators an opportunity to make more efficient use of class time and to enhance students' learning experiences by giving them more flexibility and choice in their assessment environment. In this paper, we examine the performance difference between…

  1. RELAXED ASYNCHRONOUS ITERATIONS FOR THE LINEAR COMPLEMENTARITY PROBLEM

    Institute of Scientific and Technical Information of China (English)

    Zhong-zhi Bai; Yu-guang Huang

    2002-01-01

    We present a class of relaxed asynchronous parallel multisplitting iterative methods forsolving the linear complementarity problem on multiprocessor systems, and set up theirconvergence theories when the system matrix of the linear complementarity problem is anH-matrix with positive diagonal elements.

  2. Chaos begets order: asynchronous cell contractions drive epithelial morphogenesis.

    Science.gov (United States)

    Paluch, Ewa; Heisenberg, Carl-Philipp

    2009-01-01

    Apical cell contraction triggers tissue folding and invagination in epithelia. During Drosophila gastrulation, ventral furrow formation was thought to be driven by smooth, purse-string-like constriction of an acto-myosin belt underlying adherens junctions. Now Martin et al. report in Nature that ventral furrow formation is triggered by asynchronous pulsed contractions of the apical acto-myosin cortex in individual cells.

  3. Abstracting Asynchronous Multi-Valued Networks: An Initial Investigation

    CERN Document Server

    Steggles, L Jason

    2011-01-01

    Multi-valued networks provide a simple yet expressive qualitative state based modelling approach for biological systems. In this paper we develop an abstraction theory for asynchronous multi-valued network models that allows the state space of a model to be reduced while preserving key properties of the model. The abstraction theory therefore provides a mechanism for coping with the state space explosion problem and supports the analysis and comparison of multi-valued networks. We take as our starting point the abstraction theory for synchronous multi-valued networks which is based on the finite set of traces that represent the behaviour of such a model. The problem with extending this approach to the asynchronous case is that we can now have an infinite set of traces associated with a model making a simple trace inclusion test infeasible. To address this we develop a decision procedure for checking asynchronous abstractions based on using the finite state graph of an asynchronous multi-valued network to reas...

  4. Developing a Successful Asynchronous Online Extension Program for Forest Landowners

    Science.gov (United States)

    Zobrist, Kevin W.

    2014-01-01

    Asynchronous online Extension classes can reach a wide audience, is convenient for the learner, and minimizes ongoing demands on instructor time. However, producing such classes takes significant effort up front. Advance planning and good communication with contributors are essential to success. Considerations include delivery platforms, content…

  5. Online Graduate Education: Developing Scholars through Asynchronous Discussion

    Science.gov (United States)

    Bowden, Randall

    2012-01-01

    Considerable effort has been placed on understanding and enhancing online interaction to increase student learning, examine teaching strategies, and build learning communities. This research explored another aspect of interaction: the emergence of scholarship by graduate students through asynchronous discussion. Qualitative analysis of archived…

  6. Principles for Effective Asynchronous Online Instruction in Religious Studies

    Science.gov (United States)

    McGuire, Beverley

    2017-01-01

    Asynchronous online instruction has become increasingly popular in the field of religious studies. However, despite voluminous research on online learning in general and numerous articles on online theological instruction, there has been little discussion of how to effectively design and deliver online undergraduate courses in religious studies.…

  7. Designing Asynchronous Circuits for Low Power: An IFIR Filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1999-01-01

    in the same 0.7 /spl mu/m CMOS technology. When processing typical data (less than 50 dB sound pressure), the asynchronous control and data-path logic, an improved RAM design, and by a mechanism that adapts the number range to the actual need (exploiting the fact that typical audio signals are characterized...

  8. Cyber Asynchronous versus Blended Cyber Approach in Distance English Learning

    Science.gov (United States)

    Ge, Zi-Gang

    2012-01-01

    This study aims to compare the single cyber asynchronous learning approach with the blended cyber learning approach in distance English education. Two classes of 70 students participated in this study, which lasted one semester of about four months, with one class using the blended approach for their English study and the other only using the…

  9. Reconceptualising Moderation in Asynchronous Online Discussions Using Grounded Theory

    Science.gov (United States)

    Vlachopoulos, Panos; Cowan, John

    2010-01-01

    This article reports a grounded theory study of the moderation of asynchronous online discussions, to explore the processes by which tutors in higher education decide when and how to moderate. It aims to construct a theory of e-moderation based on some key factors which appear to influence e-moderation. It discusses previous research on the…

  10. Miscellany of Students' Satisfaction in an Asynchronous Learning Environment

    Science.gov (United States)

    Larbi-Siaw, Otu; Owusu-Agyeman, Yaw

    2017-01-01

    This study investigates the determinants of students' satisfaction in an asynchronous learning environment using seven key considerations: the e-learning environment, student-content interaction, student and student interaction, student-teacher interaction, group cohesion and timely participation, knowledge of Internet usage, and satisfaction. The…

  11. Asynchronous rotation scan for synthetic aperture interferometric radiometer

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Synthetic aperture interferometric technique has wide applications in optics,radio astronomy and mi-crowave remote sensing areas.With the increasing demands of high resolution imaging observation,a new time-sharing sampling scheme of asynchronous rotation scan is proposed to meet the technical challenge of achieving a large equivalent aperture and overcome the operating barriers of space borne application.This configuration is basically composed by two asynchronously and concentrically ro-tating antenna groups,whose revolving radii and speeds are different.The synthetic aperture system with asynchronous rotation scanning scheme can effectively solve the trade-off problem of system complexity,and greatly simplify the system hardware at the cost of sacrificing a certain time resolution.The basic rules and design methods of asynchronous rotation scan are investigated The Gridding method is introduced to inverse the spiral sampling data for image reconstruction.The potential ap-plications of geostationary orbit(GEO)earth observation and solar polar orbit(SPO)plasma cloud observation are explored with numerical simulations to validate the significance and feasibility of this new imaging configuration.

  12. Teachers of the Gifted: Experiences with Asynchronous Development

    Science.gov (United States)

    Rosenberg, Jennifer

    2012-01-01

    Gifted students' development is asynchronous in the social, emotional, physical and cognitive domains. Because of this, unique interventions must be used by teachers of the gifted in order to best serve their developmental and educational needs. This qualitative study used transcendental phenomenology to examine and describe the experiences…

  13. Asynchronous Group Review of EFL Writing: Interactions and Text Revisions

    Science.gov (United States)

    Saeed, Murad Abdu; Ghazali, Kamila

    2017-01-01

    The current paper reports an empirical study of asynchronous online group review of argumentative essays among nine English as foreign language (EFL) Arab university learners joining English in their first, second, and third years at the institution. In investigating online interactions, commenting patterns, and how the students facilitate text…

  14. Asynchronous Discrete Control of Continuous Processes.

    Science.gov (United States)

    1986-02-24

    robotics or manufacturing engineering have formed a motivating tool for these efforts. This research program has had a long history and, prior to...o PP.P % %. •%%% -- 4 I - . ~ - a -.. % Printed by the St. Catherine Press Ltd., Tempelhof 41. Bruges , Belgium , % % :’ ’- a I.""---’ 22.- 2--: S

  15. An Asynchronous Electric Drive with the Indirect Control of the Output Variables

    Directory of Open Access Journals (Sweden)

    Glazachev Alexander V.

    2017-01-01

    Full Text Available The article gives a mathematical description of an asynchronous motor with a device of indirect control of the electromagnetic torque and the angular velocity of the asynchronous motor in the electric drive that allows to prove on its basis the method of monitoring the output variables of the asynchronous electric motor. The simulation model of an asynchronous motor with a device of indirect control of the output variables of the asynchronous motor and the main results of the study have been given.

  16. Design of Spiral Wheel Horizontal Well Traction Robot%螺旋轮式水平井牵引机器人设计与分析∗

    Institute of Scientific and Technical Information of China (English)

    吴超群; 刘晨阳; 刘明尧; 张凤辉; 张玺亮

    2016-01-01

    In order to efficiently transport horizontal well operation tools, a spiral drive⁃based traction robot is designed. A support bar mechanism in parallelogram is proposed, and the screw nut adjusting mechanism and flexi⁃ble spring support are adopted to meet pipe diameter changes. The positive pressure of centralized wheel and pipe wall is analyzed and a traction model for robot is established. A virtual prototype of traction robot is built by using Pro/E and ADAMS software, simulation analysis is conducted for positive pressure and traction force of the drive wheel, and pipeline test conditions are set up to conduct the robot traction force test. Test results indicate that the robot can steadily move in the pipeline with the inner diameter of 125 mm and its traction force is up to 5. 4 kN. The results have important engineering significance on design of horizontal well propeller with large traction force.%针对水平井作业工具输送困难的问题,设计了基于螺旋驱动原理的牵引机器人。提出了一种平行四边形支撑杆机构,采用丝杠螺母调节机构和弹簧柔性支撑来适应管径变化。对扶正机构轮与管壁的正压力进行分析,并建立了机器人的牵引力模型。应用P ro/E和ADAMS软件建立牵引机器人的虚拟样机,对驱动轮的正压力和牵引力进行仿真分析,搭建了管道试验环境进行机器人牵引力试验。试验结果表明:该机器人能够在内径125 mm的管道中平稳行进,最大牵引力能达到5400 N。研究结果对于设计较大牵引力的水平井推进器具有重要的工程意义。

  17. Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface

    OpenAIRE

    Chin Fhong Soon; Kian Sek Tee; Mansour Youseffi; Denyer, Morgan C. T.

    2015-01-01

    Cell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT) system can be used in conjunction with a bespoke cell traction force mapping (CTFM) software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated th...

  18. Cervical traction therapy with and without neck support: A finite element analysis.

    Science.gov (United States)

    Wang, Kuan; Wang, Huihao; Deng, Zhen; Li, Zhengyan; Zhan, Hongsheng; Niu, Wenxin

    2017-04-01

    Cervical traction is commonly used for treating neck pain. However, few studies have investigated the biomechanical impact such traction has on soft tissues. To analyze the biomechanics of cervical traction therapy in a supine position with and without neck support (NS and non-NS). A finite element model of the cervical spine was constructed to investigate the mechanism behind cervical traction therapy. An axial traction force of 100-N was loaded on the upper surface of C0 to simulate traction weight. Neck support traction was simulated by additionally constraining anterior-posterior motion of the surface of the C4 vertebral lamina. The average von Mises stress, tensile force and motions of related tissues were calculated and compared between the two conditions. Stress in the posterior annulus fibers under flexion was also recorded for comparison. At the C4-C5 and C5-C6 levels, NS traction resulted in less of a decrease in the lordotic angle. At these levels, the highest average stress was distributed in the posterior annulus fibers with non-NS traction and both traction therapies produced greater stress on the posterior annulus fibers than physical flexion. The intradiscal pressure in all intervertebral discs between C4-T1 decreased during both traction therapies. Neck support traction therapy produced less tension on the posterior annulus fibers and ligaments posterior to it at the C4-C5 and C5-C6 levels. In order to minimize the potential harm to soft tissue in clinical practice, it may be beneficial to use a neck support according to the targeted level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The Study of Cell Motility by Cell Traction Force Microscopy (CTFM).

    Science.gov (United States)

    Wang, James H-C; Zhao, Guangyi; Li, Bin

    2016-01-01

    Migration is a vital characteristic of various cell types and enables various cellular functions during development and wound healing. Cell movement can be measured by monitoring cell traction forces, which are generated by individual cells and transmitted to the substrate below the migrant cells. This method, termed cell traction force microscopy (CTFM), has the advantage of directly measuring the "cause" (i.e., cell traction forces, CTFs) of cell movement rather than the "effect" (i.e., cell movement itself). This chapter details the methods involved in measuring cell traction forces. Several examples are also given to illustrate various applications of CTFM in cell biology research.

  20. The investigation of reverse traction current influence on tone track circuit modes

    Directory of Open Access Journals (Sweden)

    E.I.Jasсhuk

    2012-12-01

    Full Text Available Introduction: With the introduction of high-speed traffic there is an increased consumption of traction current by new types of rolling stock. This issue is important, as high levels of traction currents can have not only prevents, but also a dangerous impact on the equipment of railway automation devices. It is necessary to investigate the propagation of traction currents and potentials along the rails. Objective: Investigate the propagation of traction currents and potentials along the rails, the determination of critical currents, which not executed tone track circuits modes. Methods: In order to investigate the mathematical model, and the method of calculation tone track circuits modes was used. Results: By means of mathematical model, which includes being several rolling-stocks at the feeder zone, different rail resistance and isolation, the diagrams of currents and potentials propagations for DC and AC electric traction have been obtained. A comparative analysis of the experimental data and the results of the investigation has been realized. Based on received levels of reverse traction current their influence on track circuit modes has been investigated. Conclusions: The reverse traction current level near the substation and rolling-stock can be more than 600A. Great reverse traction current levels have an influence on tonal track circuit functioning, namely normal and shunt modes. When the traction current arrives 200 A there is a reduction criteria of tonal track circuits.

  1. Collective cell traction force analysis on aligned smooth muscle cell sheet between three-dimensional microwalls.

    Science.gov (United States)

    Zhang, Ying; Ng, Soon Seng; Wang, Yilei; Feng, Huixing; Chen, Wei Ning; Chan-Park, Mary B; Li, Chuan; Chan, Vincent

    2014-04-06

    During the past two decades, novel biomaterial scaffold for cell attachment and culture has been developed for applications in tissue engineering, biosensing and regeneration medicine. Tissue engineering of blood vessels remains a challenge owing to the complex three-layer histology involved. In order to engineer functional blood vessels, it is essential to recapitulate the characteristics of vascular smooth muscle cells (SMCs) inside the tunica media, which is known to be critical for vasoconstriction and vasodilation of the circulatory system. Until now, there has been a lack of understanding on the mechanotransduction of the SMC layer during the transformation from viable synthetic to quiescent contractile phenotypes. In this study, microfabricated arrays of discontinuous microwalls coated with fluorescence microbeads were developed to probe the mechanotransduction of the SMC layer. First, the system was exploited for stimulating the formation of a highly aligned orientation of SMCs in native tunica medium. Second, atomic force microscopy in combination with regression analysis was applied to measure the elastic modulus of a polyacrylamide gel layer coated on the discontinuous microwall arrays. Third, the conventional traction force assay for single cell measurement was extended for applications in three-dimensional cell aggregates. Then, the biophysical effects of discontinuous microwalls on the mechanotransduction of the SMC layer undergoing cell alignment were probed. Generally, the cooperative multiple cell-cell and cell-microwall interactions were accessed quantitatively by the newly developed assay with the aid of finite-element modelling. The results show that the traction forces of highly aligned cells lying in the middle region between two opposing microwalls were significantly lower than those lying adjacent to the microwalls. Moreover, the spatial distributions of Von Mises stress during the cell alignment process were dependent on the collective cell

  2. 交流传动牵引变流器的技术发展%Technical development of AC drive traction converter

    Institute of Scientific and Technical Information of China (English)

    刘连根

    2001-01-01

    The basic circuit principle of AC drive traction converters is introduced, whose technical characteristics and development process are also described in details combinating the main parameters of traction converters for AC drive locomotives, such as DJ electric locomotive, NJ1 diesel locomotive and DWA metro engineering machine.%阐述了交流传动牵引变流器的基本电路原理,结合国产DJ型电力机车、NJ1型内燃机车、DWA型地铁工程车等交流传动机车牵引变流器的主要技术参数,对交流传动牵引变流器的技术特点及其发展过程作了较为详细的叙述。

  3. Two Distinct Actin Networks Mediate Traction Oscillations to Confer Focal Adhesion Mechanosensing.

    Science.gov (United States)

    Wu, Zhanghan; Plotnikov, Sergey V; Moalim, Abdiwahab Y; Waterman, Clare M; Liu, Jian

    2017-02-28

    Focal adhesions (FAs) are integrin-based transmembrane assemblies that connect a cell to its extracellular matrix (ECM). They are mechanosensors through which cells exert actin cytoskeleton-mediated traction forces to sense the ECM stiffness. Interestingly, FAs themselves are dynamic structures that adapt their growth in response to mechanical force. It is unclear how the cell manages the plasticity of the FA structure and the associated traction force to accurately sense ECM stiffness. Strikingly, FA traction forces oscillate in time and space, and govern the cell mechanosensing of ECM stiffness. However, precisely how and why the FA traction oscillates is unknown. We developed a model of FA growth that integrates the contributions of the branched actin network and stress fibers (SFs). Using the model in combination with experimental tests, we show that the retrograde flux of the branched actin network promotes the proximal growth of the FA and contributes to a traction peak near the FA's distal tip. The resulting traction gradient within the growing FA favors SF formation near the FA's proximal end. The SF-mediated actomyosin contractility further stabilizes the FA and generates a second traction peak near the center of the FA. Formin-mediated SF elongation negatively feeds back with actomyosin contractility, resulting in central traction peak oscillation. This underpins the observed FA traction oscillation and, importantly, broadens the ECM stiffness range over which FAs can accurately adapt to traction force generation. Actin cytoskeleton-mediated FA growth and maturation thus culminate with FA traction oscillation to drive efficient FA mechanosensing. Published by Elsevier Inc.

  4. Matrix identity and tractional forces influence indirect cardiac reprogramming

    Science.gov (United States)

    Kong, Yen P.; Carrion, Bita; Singh, Rahul K.; Putnam, Andrew J.

    2013-12-01

    Heart regeneration through in vivo cardiac reprogramming has been demonstrated as a possible regenerative strategy. While it has been reported that cardiac reprogramming in vivo is more efficient than in vitro, the influence of the extracellular microenvironment on cardiac reprogramming remains incompletely understood. This understanding is necessary to improve the efficiency of cardiac reprogramming in order to implement this strategy successfully. Here we have identified matrix identity and cell-generated tractional forces as key determinants of the dedifferentiation and differentiation stages during reprogramming. Cell proliferation, matrix mechanics, and matrix microstructure are also important, but play lesser roles. Our results suggest that the extracellular microenvironment can be optimized to enhance cardiac reprogramming.

  5. Model-based efficiency evaluation of combine harvester traction drives

    Directory of Open Access Journals (Sweden)

    Steffen Häberle

    2015-08-01

    Full Text Available As part of the research the drive train of the combine harvesters is investigated in detail. The focus on load and power distribution, energy consumption and usage distribution are explicitly explored on two test machines. Based on the lessons learned during field operations, model-based studies of energy saving potential in the traction train of combine harvesters can now be quantified. Beyond that the virtual machine trial provides an opportunity to compare innovative drivetrain architectures and control solutions under reproducible conditions. As a result, an evaluation method is presented and generically used to draw comparisons under local representative operating conditions.

  6. FreedomCAR Advanced Traction Drive Motor Development Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Ley, Josh (UQM Technologies, Inc.); Lutz, Jon (UQM Technologies, Inc.)

    2006-09-01

    The overall objective of this program is to design and develop an advanced traction motor that will meet the FreedomCAR and Vehicle Technologies (FCVT) 2010 goals and the traction motor technical targets. The motor specifications are given in Section 1.3. Other goals of the program include providing a cost study to ensure the motor can be developed within the cost targets needed for the automotive industry. The program has focused on using materials that are both high performance and low costs such that the performance can be met and cost targets are achieved. In addition, the motor technologies and machine design features must be compatible with high volume manufacturing and able to provide high reliability, efficiency, and ruggedness while simultaneously reducing weight and volume. Weight and volume reduction will become a major factor in reducing cost, material cost being the most significant part of manufacturing cost at high volume. Many motor technology categories have been considered in the past and present for traction drive applications, including: brushed direct current (DC), PM (PM) brushless dc (BLDC), alternating current (AC) induction, switched reluctance and synchronous reluctance machines. Of these machine technologies, PM BLDC has consistently demonstrated an advantage in terms of power density and efficiency. As rare earth magnet cost has declined, total cost may also be reduced over the other technologies. Of the many different configurations of PM BLDC machines, those which incorporate power production utilizing both magnetic torque as well as reluctance torque appear to have the most promise for traction applications. There are many different PM BLDC machine configurations which employ both of these torque producing mechanisms; however, most would fall into one of two categories--some use weaker magnets and rely more heavily on reluctance torque (reluctance-dominant PM machines), others use strong PMs and supplement with reluctance torque

  7. Mathematical model of traction electric drive for mine electric train

    Directory of Open Access Journals (Sweden)

    Kladiev S.N.

    2014-01-01

    Full Text Available In this paper a mathematical description of a traction electric motor for a mine electric locomotive which takes into account skidding effect as a difference between linear speeds of wheel pairs and linear speed of locomotive is proposed. Obtained mathematical description enables to synthesize the PI-control which compensates the skidding effect and gives ability to carry out an optimal motion. This control scheme is implemented by means of low pass filter, band-pass filter and absolute value calculator.

  8. Asynchronous telehealth: a scoping review of analytic studies.

    Science.gov (United States)

    Deshpande, Amol; Khoja, Shariq; Lorca, Julio; McKibbon, Ann; Rizo, Carlos; Husereau, Donald; Jadad, Alejandro R

    2009-06-02

    Asynchronous telehealth captures clinically important digital samples (e.g., still images, video, audio, text files) and relevant data in one location and subsequently transmits these files for interpretation at a remote site by health professionals without requiring the simultaneous presence of the patient involved and his or her health care provider. Its utility in the health care system, however, still remains poorly defined. We conducted this scoping review to determine the impact of asynchronous telehealth on health outcomes, process of care, access to health services, and health resources. A search was performed up to December 2006 of MEDLINE, CINAHL, HealthSTAR, the Database of Abstracts of Reviews of Effectiveness, and The Cochrane Library. Studies were included if they contained original data on the use of asynchronous telehealth and were published in English in a peer-reviewed journal. Two independent reviewers screened all articles and extracted data, reaching consensus on the articles and data identified. Data were extracted on general study characteristics, clinical domain, technology, setting, category of outcome, and results. Study quality (internal validity) was assessed using the Jadad scale for randomized controlled trials and the Downs and Black index for non-randomized studies. Summary data were categorized by medical specialty and presented qualitatively. The scoping review included 52 original studies from 238 citations identified; of these 52, almost half focused on the use of telehealth in dermatology. Included studies were characterized by diverse designs, interventions, and outcomes. Only 16 studies were judged to be of high quality. Most studies showed beneficial effects in terms of diagnostic accuracy, wait times, referral management, and satisfaction with services. Evidence on the impact of asynchronous telehealth on resource use in dermatology suggests a reduction in the number of, or avoidance of, in-person visits. Reports from other

  9. 牵引式无级变速器牵引效率研究%Study of traction efficiency on traction type continuously variahle transmission

    Institute of Scientific and Technical Information of China (English)

    李忠

    2012-01-01

    By taking the traction type continuously variable transmission as the study object. Some analytic expressions for angular speed of spin, traction force caused by oil film sliding and moment generated by spinning are derived. By means of a real example, the changing regularity among traction efficiency and contact pressure, traction force of oil film, input rotation speed and geometric curvature ratio was calculated and analyzed.%以牵引式无级变速器为研究对象,推导出了自转角速度、由油膜滑动产生的牵引力和由自转产生的力矩等解析式.通过实例,计算和分析了牵引效率与接触压力、油膜牵引力、输入转速和几何曲率比等因素间的变化规律.

  10. THE MINIMALIZATION OF FILTER EQUIPMENT FOR TRACTION SUBSTATIONS USING BOOSTER CONVERTER

    Directory of Open Access Journals (Sweden)

    Yu. P. Goncharov

    2008-12-01

    Full Text Available The structure of traction substation 3,2 kV DC power source is considered. It is shown that the output filter choke of traction substation with voltage added converter may be excluded. A dynamic model of voltage added converter is developed, its features, as an active filter, are described.

  11. THE ANALYSIS OF STEADY VOLTAGE ON THE ACCESSION OF DC TRACTION SUBSTATIONS

    Directory of Open Access Journals (Sweden)

    V. H. Sychenko

    2009-09-01

    Full Text Available Research results of voltage modes at traction substation buses in primary, regional and traction network are presented in the article. Numeric characteristics of probability density distributions are obtained. Autocorrelation functions of positive and negative sequence voltages are analyzed.

  12. The Harmonoise/IMAGINE model for traction noise of powered railway vehicles

    NARCIS (Netherlands)

    Dittrich, M.G.; Zhang, X.

    2006-01-01

    Traction noise is one of the noise sources of powered railway vehicles such as locomotives, electric- and diesel-powered multiple unit trains and high-speed trains. Especially at speeds below 60 km/h and at idling, but also at acceleration conditions for a wide range of speeds, traction noise can be

  13. Changes in dynamics processes of the muscles’ traction under influence of stress-factors

    Directory of Open Access Journals (Sweden)

    D. M. Nozdrenko

    2006-01-01

    Full Text Available Change of fibers’ dynamic parameters of the frog Rana temporaria skeletal muscle m. tibialis traction under influence of modulated stimulation and aluminium chloride solutions was studied. At 10-4,5·10-4 and 10‑3 M·l-1 concentrations of aluminium chloride the nonlinear decrease of the muscle fibers’ traction parameters was observed.

  14. Substrate Stiffness and Cell Area Predict Cellular Traction Stresses in Single Cells and Cells in Contact.

    Science.gov (United States)

    Califano, Joseph P; Reinhart-King, Cynthia A

    2010-03-01

    Cells generate traction stresses against their substrate during adhesion and migration, and traction stresses are used in part by the cell to sense the substrate. While it is clear that traction stresses, substrate stiffness, and cell area are related, it is unclear whether or how area and substrate stiffness affect force generation in cells. Moreover, multiple studies have investigated traction stresses of single cells, but few have focused on forces exerted by cells in contact, which more closely mimics the in vivo environment. Here, cellular traction forces were measured where cell area was modulated by ligand density or substrate stiffness. We coupled these measurements with a multilinear regression model to show that both projected cell area and underlying substrate stiffness are significant predictors of traction forces in endothelial cells, and interestingly, substrate ligand density is not. We further explored the effect of cell-cell contact on the interplay between cell area, substrate stiffness, and force generation and found that again both area and stiffness play a significant role in cell force generation. These data indicate that cellular traction force cannot be determined by cell area alone and that underlying substrate stiffness is a significant contributor to traction force generation.

  15. Two distinct actin networks mediate traction oscillations to confer mechanosensitivity of focal adhesions

    Science.gov (United States)

    Wu, Zhanghan; Plotnikov, Sergey; Waterman, Clare; Liu, Jian

    Cells sense the mechanical stiffness of their extracellular matrix (ECM) by exerting traction force through focal adhesions (FAs), which are integrin-based protein assemblies. Strikingly, FA-mediated traction forces oscillate in time and space and govern durotaxis - the tendency of most cell types to migrate toward stiffer ECM. The underlying mechanism of this intriguing oscillation of FA traction force is unknown. Combing theory and experiment, we develop a model of FA growth, which integrates coordinated contributions of a branched actin network and stress fibers in the process. We show that retrograde flux of branched actin network contributes to a traction peak near the FA distal tip and that stress fiber-mediated actomyosin Contractility generates a second traction peak near the FA center. Formin-mediated stress fiber elongation negatively feeds back with actomyosin Contractility, resulting in the central traction peak oscillation. This underpins observed spatio-temporal patterns of the FA traction, and broadens the ECM stiffness range, over which FAs could accurately adapt with traction force generation. Our findings shed light on the fundamental mechanism of FA mechanosensing and hence durotaxis.

  16. Applications of Traction Force Microscopy in Measuring Adhesion Molecule Dependent Cell Contractility

    Science.gov (United States)

    Mann, Cynthia Marie

    2009-01-01

    This work describes the use of polyacrylamide hydrogels as controlled elastic modulus substrates for single cell traction force microscopy studies. The first section describes the use of EDC/NHS chemistry to convalently link microbeads to the hydrogel matrix for the purpose of performing long-term traction force studies (7 days). The final study…

  17. State assignment approach to asynchronous CMOS circuit design

    Science.gov (United States)

    Kantabutra, Vitit; Andreou, Andreas G.

    1994-04-01

    We present a new algorithm for state assignment in asynchronous circuits so that for each circuit state transition, only one (secondary) state variable switches. No intermediate unstable states are used. The resultant circuits operate at optimum speed in terms of the number of transitions made and use only static CMOS gates. By reducing the number of switching events per state transition, noise due to the switching events is reduced and dynamic power dissipation may also be reduced. Our approach is suitable for asynchronous sequential circuits that are designed from flow tables or state transition diagrams. The proposed approach may also be useful for designing synchronous circuits, but explorations into the subject of clock power would be necessary to determine its usefulness.

  18. Inference of asynchronous Boolean network from biological pathways.

    Science.gov (United States)

    Das, Haimabati; Layek, Ritwik Kumar

    2015-01-01

    Gene regulation is a complex process with multiple levels of interactions. In order to describe this complex dynamical system with tractable parameterization, the choice of the dynamical system model is of paramount importance. The right abstraction of the modeling scheme can reduce the complexity in the inference and intervention design, both computationally and experimentally. This article proposes an asynchronous Boolean network framework to capture the transcriptional regulation as well as the protein-protein interactions in a genetic regulatory system. The inference of asynchronous Boolean network from biological pathways information and experimental evidence are explained using an algorithm. The suitability of this paradigm for the variability of several reaction rates is also discussed. This methodology and model selection open up new research challenges in understanding gene-protein interactive system in a coherent way and can be beneficial for designing effective therapeutic intervention strategy.

  19. Channel Estimation And Multiuser Detection In Asynchronous Satellite Communications

    CERN Document Server

    Chaouech, Helmi; 10.5121/ijwmn.2010.2411

    2010-01-01

    In this paper, we propose a new method of channel estimation for asynchronous additive white Gaussian noise channels in satellite communications. This method is based on signals correlation and multiuser interference cancellation which adopts a successive structure. Propagation delays and signals amplitudes are jointly estimated in order to be used for data detection at the receiver. As, a multiuser detector, a single stage successive interference cancellation (SIC) architecture is analyzed and integrated to the channel estimation technique and the whole system is evaluated. The satellite access method adopted is the direct sequence code division multiple access (DS CDMA) one. To evaluate the channel estimation and the detection technique, we have simulated a satellite uplink with an asynchronous multiuser access.

  20. Ultra Low Energy FDSOI Asynchronous Reconfiguration Network for Adaptive Circuits

    Directory of Open Access Journals (Sweden)

    Soundous Chairat

    2017-05-01

    Full Text Available This paper introduces a plug-and-play on-chip asynchronous communication network aimed at the dynamic reconfiguration of a low-power adaptive circuit such as an internet of things (IoT system. By using a separate communication network, we can address both digital and analog blocks at a lower configuration cost, increasing the overall system power efficiency. As reconfiguration only occurs according to specific events and has to be automatically in stand-by most of the time, our design is fully asynchronous using handshake protocols. The paper presents the circuit’s architecture, performance results, and an example of the reconfiguration of frequency locked loops (FLL to validate our work. We obtain an overall energy per bit of 0.07 pJ/bit for one stage, in a 28 nm Fully Depleted Silicon On Insulator (FDSOI technology at 0.6 V and a 1.1 ns/bit latency per stage.

  1. Periodic traction in migrating large amoeba of Physarum polycephalum.

    Science.gov (United States)

    Rieu, Jean-Paul; Delanoë-Ayari, Hélène; Takagi, Seiji; Tanaka, Yoshimi; Nakagaki, Toshiyuki

    2015-05-01

    The slime mould Physarum polycephalum is a giant multinucleated cell exhibiting well-known Ca(2+)-dependent actomyosin contractions of its vein network driving the so-called cytoplasmic shuttle streaming. Its actomyosin network forms both a filamentous cortical layer and large fibrils. In order to understand the role of each structure in the locomotory activity, we performed birefringence observations and traction force microscopy on excised fragments of Physarum. After several hours, these microplasmodia adopt three main morphologies: flat motile amoeba, chain types with round contractile heads connected by tubes and motile hybrid types. Each type exhibits oscillations with a period of about 1.5 min of cell area, traction forces and fibril activity (retardance) when fibrils are present. The amoeboid types show only peripheral forces while the chain types present a never-reported force pattern with contractile rings far from the cell boundary under the spherical heads. Forces are mostly transmitted where the actomyosin cortical layer anchors to the substratum, but fibrils maintain highly invaginated structures and contribute to forces by increasing the length of the anchorage line. Microplasmodia are motile only when there is an asymmetry in the shape and/or the force distribution.

  2. Friction-controlled traction force in cell adhesion.

    Science.gov (United States)

    Pompe, Tilo; Kaufmann, Martin; Kasimir, Maria; Johne, Stephanie; Glorius, Stefan; Renner, Lars; Bobeth, Manfred; Pompe, Wolfgang; Werner, Carsten

    2011-10-19

    The force balance between the extracellular microenvironment and the intracellular cytoskeleton controls the cell fate. We report a new (to our knowledge) mechanism of receptor force control in cell adhesion originating from friction between cell adhesion ligands and the supporting substrate. Adherent human endothelial cells have been studied experimentally on polymer substrates noncovalently coated with fluorescent-labeled fibronectin (FN). The cellular traction force correlated with the mobility of FN during cell-driven FN fibrillogenesis. The experimental findings have been explained within a mechanistic two-dimensional model of the load transfer at focal adhesion sites. Myosin motor activity in conjunction with sliding of FN ligands noncovalently coupled to the surface of the polymer substrates is shown to result in a controlled traction force of adherent cells. We conclude that the friction of adhesion ligands on the supporting substrate is important for mechanotransduction and cell development of adherent cells in vitro and in vivo. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Diversity Multiplexing Tradeoff of Asynchronous Cooperative Relay Networks

    CERN Document Server

    Krishnakumar, R N; Kumar, P Vijay

    2008-01-01

    The assumption of nodes in a cooperative communication relay network operating in synchronous fashion is often unrealistic. In the present paper, we consider two different models of asynchronous operation in cooperative-diversity networks experiencing slow fading and examine the corresponding diversity-multiplexing tradeoffs (DMT). For both models, we propose protocols and distributed space-time codes that asymptotically achieve the transmit diversity bound for all multiplexing gains and for any number of relays.

  4. Asynchronous Transfer Mode (ATM) Switch Technology and Vendor Survey

    Science.gov (United States)

    Berry, Noemi

    1995-01-01

    Asynchronous Transfer Mode (ATM) switch and software features are described and compared in order to make switch comparisons meaningful. An ATM switch's performance cannot be measured solely based on its claimed switching capacity; traffic management and congestion control are emerging as the determining factors in an ATM network's ultimate throughput. Non-switch ATM products and experiences with actual installations of ATM networks are described. A compilation of select vendor offerings as of October 1994 is provided in chart form.

  5. IDENTIFICATION AND CONTROL OF AN ASYNCHRONOUS MACHINE USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    A ZERGAOUI

    2000-06-01

    Full Text Available In this work, we present the application of artificial neural networks to the identification and control of the asynchronous motor, which is a complex nonlinear system with variable internal dynamics.  We show that neural networks can be applied to control the stator currents of the induction motor.  The results of the different simulations are presented to evaluate the performance of the neural controller proposed.

  6. Synthèse automatique de circuits asynchrones QDI

    OpenAIRE

    DINH DUC, Anh Vu

    2003-01-01

    ISBN 2-84813-010-5; Contrary to the synchronous circuits, the asynchronous circuits operate with a mechanism of local synchronization (without clock signal). Since many years, they showed their relevance with respect to the synchronous circuits thanks to their properties of robustness, low power, low noise and modularity. However, the current lack of design methods and associated tools prevents them from being widely spread. This dissertation deals with a new design methodology for quasi-dela...

  7. PersisDroid: Android Performance Diagnosis via Anatomizing Asynchronous Executions

    OpenAIRE

    Kang, Yu; Zhou, Yangfan; Xu, Hui; Lyu, Michael R.

    2015-01-01

    Android applications (apps) grow dramatically in recent years. Apps are user interface (UI) centric typically. Rapid UI responsiveness is key consideration to app developers. However, we still lack a handy tool for profiling app performance so as to diagnose performance problems. This paper presents PersisDroid, a tool specifically designed for this task. The key notion of PersisDroid is that the UI-triggered asynchronous executions also contribute to the UI performance, and hence its perform...

  8. Marine Forces Reserve: Accelerating Knowledge Flow through Asynchronous Learning Technologies

    Science.gov (United States)

    2014-12-19

    pedagogic techniques that are infeasible in the classroom , and they suggest that in some respects technologically intermediated learning can be even better...frameworks and technologies to examine I-I knowledge flows, and from the practitioner perspective, we bring to bear deep inside knowledge of the focal...ASYNCHRONOUS LEARNING TECHNOLOGIES by Mark Nissen, Robert McGuiness and Anthony Davis December 2014 Further distribution of all or part of this

  9. Pipelined asynchronous time-division multiplexing optical bus

    Science.gov (United States)

    Zheng, S. Q.; Li, Yueming

    1997-12-01

    We propose a pipelined asynchronous time-division multiplexing optical bus. Such a bus can use one of two hardwared priority schemes: the linear priority scheme and the round-robin priority scheme. Our simulation results show that the performance of the proposed bus is significantly better than the performances of known pipelined synchronous time-division multiplexing optical buses. The possibilities of using our buses to construct multichannel switches and multidimensional processor arrays are also discussed.

  10. Financial Data Modeling by Using Asynchronous Parallel Evolutionary Algorithms

    Institute of Scientific and Technical Information of China (English)

    Wang Chun; Li Qiao-yun

    2003-01-01

    In this paper, the high-level knowledge of financial data modeled by ordinary differential equations (ODEs) is discovered in dynamic data by using an asynchronous parallel evolutionary modeling algorithm (APHEMA). A numerical example of Nasdaq index analysis is used to demonstrate the potential of APHEMA. The results show that the dynamic models automatically discovered in dynamic data by computer can be used to predict the financial trends.

  11. Bilateral Vitreopapillary Traction Demonstrated by Optical Coherence Tomography Mistaken for Papilledema

    Directory of Open Access Journals (Sweden)

    Elizabeth Houle

    2012-01-01

    Full Text Available Purpose. The purpose of this study was to report a case of bilateral vitreopapillary traction, previously misdiagnosed as papilledema. Methods. A case report is presented of a 47-year-old woman with a prior diagnosis of papilledema, who is shown to have bilateral vitreopapillary traction rather than true optic disc swelling, confirmed by optical coherence tomography (OCT. Results. OCT showed vitreous traction surrounding the optic discs of both eyes. Fluorescein angiography demonstrated focal leakage of both discs. Conclusion. Bilateral disc elevation caused by vitreous traction can be confused with papilledema. In such cases, OCT can be used to arrive at the correct diagnosis. Although the phenomenon of vitreopapillary traction is well reported, this case indicates that not all ophthalmologists recognize the condition.

  12. Scaling of traction forces with the size of cohesive cell colonies.

    Science.gov (United States)

    Mertz, Aaron F; Banerjee, Shiladitya; Che, Yonglu; German, Guy K; Xu, Ye; Hyland, Callen; Marchetti, M Cristina; Horsley, Valerie; Dufresne, Eric R

    2012-05-11

    To understand how the mechanical properties of tissues emerge from interactions of multiple cells, we measure traction stresses of cohesive colonies of 1-27 cells adherent to soft substrates. We find that traction stresses are generally localized at the periphery of the colony and the total traction force scales with the colony radius. For large colony sizes, the scaling appears to approach linear, suggesting the emergence of an apparent surface tension of the order of 10(-3)  N/m. A simple model of the cell colony as a contractile elastic medium coupled to the substrate captures the spatial distribution of traction forces and the scaling of traction forces with the colony size.

  13. Comparison of the environmental performance of light mechanization and animal traction using a modular LCA approach

    DEFF Research Database (Denmark)

    Cerutti, Alessandro K.; Calvo, Angela; Bruun, Sander

    2014-01-01

    operations. This achievement completely changed food production systems for all populations able to access such technology. Nowadays, animal traction is mainly used in the developing countries, in specific contexts such as mountainous areas due to the difficulties in using tractors, and within farm tourism...... life cycle impact assessment phase was performed and results were related to the contribution of the module in the main workflow of the scenario. The final results showed better environmental performance of animal traction both per unit weight of market-ready wood and per unit surface area of prepared...... in the developed countries. Although the consumption of non-renewable resources is clearly higher in crop production systems that use mechanized traction, tractor traction may involve low consumption of fuel relative to that needed for feed production for equivalent draught animals. Mechanical traction can also...

  14. Effects of intermittent traction therapy in an experimental spinal column model.

    Science.gov (United States)

    Shin, Jeong-Hun; Jun, Seung-lyul; Lee, Young-Jun; Kim, Jae-Hyo; Hwang, Sung-Yeoun; Ahn, Seong-Hun

    2014-04-01

    Traction therapy, which is known to be a treatment method for scoliosis, one of many muscles disease, has been used since Hippocrates introduced it. However, the effects of traction therapy are still not clear. In addition, the meridian sinew theory, which is related to muscle treatment and is mentioned in the book on meridian sinews in the Miraculous Pivot of Huangdi's Internal Classic, has not been the subject of much study. For these reasons, experimental spinal models were made for this study to observe and analyze the lengths of vertebral interspaces after intermittent traction therapy, which is known to be excellent among muscle treatment methods, with various tensile forces. The results showed that the effects of intermittent traction therapy were unclear and that it might be harmful, especially when the pain was induced by muscle weakness. Because the results of this study on intermittent traction therapy were different from those expected from osteopathy or craniosacral theory, better studies of the subject are necessary.

  15. Friction self-oscillation decrease in nonlinear system of locomotive traction drive

    Science.gov (United States)

    Antipin, D. Ya; Vorobiyov, V. I.; Izmerov, O. V.; Shorokhov, S. G.; Bondarenko, D. A.

    2017-02-01

    The problems of the friction self-oscillation decrease in a nonlinear system of a locomotive traction drive are considered. It is determined that the self-oscillation amplitude decrease in a locomotive wheel pair during boxing in traction drives with an elastic linkage between an armature of a traction electric motor and gearing can be achieved due to drive damping capacity during impact vibro-damping in an axle reduction gear with a hard driven gear. The self-oscillation amplitude reduction in a wheel pair in the designs of locomotive traction drives with the location of elastic elements between a wheel pair and gearing can be obtained owing to the application of drive inertial masses as an anti-vibrator. On the basis of the carried out investigations, a design variant of a self-oscillation shock absorber of a traction electric motor framework on a reduction gear suspension with an absorber located beyond a wheel-motor unit was offered.

  16. Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach.

    Science.gov (United States)

    Zhu, Weiping; Chen, Weiran; Hu, Zhejie; Li, Zuoyou; Liang, Yue; Chen, Jiaojiao

    2016-04-06

    Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption.

  17. Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

    Science.gov (United States)

    Marisa, T; Niederhauser, T; Haeberlin, A; Wildhaber, R A; Vogel, R; Goette, J; Jacomet, M

    2017-02-07

    A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing. The architecture offers the advantages of smaller chip area, energy saving and fewer analogue system components. Beside lower energy consumption the use of dynamic comparators results in a more robust performance in noise conditions. Moreover, dynamic comparators make interfacing the asynchronous level crossing system to synchronous processing blocks simpler. The proposed adc was implemented in [Formula: see text] complementary metal-oxide-semiconductor (cmos) technology, the hardware occupies a chip area of 0.0372 mm(2) and operates from a supply voltage of [Formula: see text] to [Formula: see text]. The adc's power consumption is as low as 0.6 μW with signal bandwidth from [Formula: see text] to [Formula: see text] and achieves an equivalent number of bits (enob) of up to 8 bits.

  18. Asynchronous signal-dependent non-uniform sampler

    Science.gov (United States)

    Can-Cimino, Azime; Chaparro, Luis F.; Sejdić, Ervin

    2014-05-01

    Analog sparse signals resulting from biomedical and sensing network applications are typically non-stationary with frequency-varying spectra. By ignoring that the maximum frequency of their spectra is changing, uniform sampling of sparse signals collects unnecessary samples in quiescent segments of the signal. A more appropriate sampling approach would be signal-dependent. Moreover, in many of these applications power consumption and analog processing are issues of great importance that need to be considered. In this paper we present a signal dependent non-uniform sampler that uses a Modified Asynchronous Sigma Delta Modulator which consumes low-power and can be processed using analog procedures. Using Prolate Spheroidal Wave Functions (PSWF) interpolation of the original signal is performed, thus giving an asynchronous analog to digital and digital to analog conversion. Stable solutions are obtained by using modulated PSWFs functions. The advantage of the adapted asynchronous sampler is that range of frequencies of the sparse signal is taken into account avoiding aliasing. Moreover, it requires saving only the zero-crossing times of the non-uniform samples, or their differences, and the reconstruction can be done using their quantized values and a PSWF-based interpolation. The range of frequencies analyzed can be changed and the sampler can be implemented as a bank of filters for unknown range of frequencies. The performance of the proposed algorithm is illustrated with an electroencephalogram (EEG) signal.

  19. Asynchronous Stoichiometric Response in Lithium Iron Phosphate Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Paxton, William A. [State Univ. of New Jersey, Piscataway, NJ (United States); Akdogan, E. Koray [State Univ. of New Jersey, Piscataway, NJ (United States); Savkliyidiz, Ilyas [State Univ. of New Jersey, Piscataway, NJ (United States); Choksi, Ankur U. [State Univ. of New Jersey, Piscataway, NJ (United States); Silver, Scott X. [State Univ. of New Jersey, Piscataway, NJ (United States); Tsakalokos, Thomas [State Univ. of New Jersey, Piscataway, NJ (United States); Zhong, Zhong [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-11

    The operando energy-dispersive x-ray diffraction (EDXRD) was carried out on a newly formed 8 Ah lithium iron phosphate (LiFePO4) battery with the goal of elucidating the origin of asynchronous phase transformation commonly seen with in situ x-ray diffraction studies. The high-energy photons at the NSLS X17B1 beamline allow for penetration into a fully assembled battery and therefore negate any need for a specially designed in situ cell which often uses modified current collectors to minimize x-ray attenuation. Spatially-and-temporally resolved phase-mapping was conducted with a semiquantitative reference intensity ratio (RIR) analysis to estimate the relative abundance of the delithiated phase. The data show an asynchronous response in the stoichiometry versus the electrochemical profile and suggest limited diffusion in the electrode toward the end of discharge. These results confirm that the asynchronous electrode response is not just limited to specially designed cells but occurs in fully assembled cells alike. We attribute this behavior to be a consequence of performing a local measurement over a wide-area heterogeneous reaction.

  20. A novel asynchronous access method with binary interfaces

    Directory of Open Access Journals (Sweden)

    Torres-Solis Jorge

    2008-10-01

    Full Text Available Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches. Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation.

  1. A Synchronous-Asynchronous Particle Swarm Optimisation Algorithm

    Directory of Open Access Journals (Sweden)

    Nor Azlina Ab Aziz

    2014-01-01

    Full Text Available In the original particle swarm optimisation (PSO algorithm, the particles’ velocities and positions are updated after the whole swarm performance is evaluated. This algorithm is also known as synchronous PSO (S-PSO. The strength of this update method is in the exploitation of the information. Asynchronous update PSO (A-PSO has been proposed as an alternative to S-PSO. A particle in A-PSO updates its velocity and position as soon as its own performance has been evaluated. Hence, particles are updated using partial information, leading to stronger exploration. In this paper, we attempt to improve PSO by merging both update methods to utilise the strengths of both methods. The proposed synchronous-asynchronous PSO (SA-PSO algorithm divides the particles into smaller groups. The best member of a group and the swarm’s best are chosen to lead the search. Members within a group are updated synchronously, while the groups themselves are asynchronously updated. Five well-known unimodal functions, four multimodal functions, and a real world optimisation problem are used to study the performance of SA-PSO, which is compared with the performances of S-PSO and A-PSO. The results are statistically analysed and show that the proposed SA-PSO has performed consistently well.

  2. Pharmacists' perception of synchronous versus asynchronous distance learning for continuing education programs.

    Science.gov (United States)

    Buxton, Eric C

    2014-02-12

    To evaluate and compare pharmacists' satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars. An 8-lecture series of online presentations on the topic of new drug therapies was offered to pharmacists in synchronous and asynchronous webinar formats. Participants completed a 50-question online survey at the end of the program series to evaluate their perceptions of the distance learning experience. Eighty-two participants completed the survey instrument (41 participants from the live webinar series and 41 participants from the asynchronous webinar series.) Responses indicated that while both groups were satisfied with the program content, the asynchronous group showed greater satisfaction with many aspects of the learning environment. The synchronous and asynchronous webinar participants responded positively regarding the quality of the programming and the method of delivery, but asynchronous participants rated their experience more positively overall.

  3. Pharmacists’ Perception of Synchronous Versus Asynchronous Distance Learning for Continuing Education Programs

    Science.gov (United States)

    2014-01-01

    Objective. To evaluate and compare pharmacists’ satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars. Methods. An 8-lecture series of online presentations on the topic of new drug therapies was offered to pharmacists in synchronous and asynchronous webinar formats. Participants completed a 50-question online survey at the end of the program series to evaluate their perceptions of the distance learning experience. Results. Eighty-two participants completed the survey instrument (41 participants from the live webinar series and 41 participants from the asynchronous webinar series.) Responses indicated that while both groups were satisfied with the program content, the asynchronous group showed greater satisfaction with many aspects of the learning environment. Conclusion. The synchronous and asynchronous webinar participants responded positively regarding the quality of the programming and the method of delivery, but asynchronous participants rated their experience more positively overall. PMID:24558276

  4. Development And Use Of Advanced Microfabricated Traction Force Sensing Substrates To Study The Effect of Nanosilver On Human Macrophages

    Science.gov (United States)

    Stark, Daniel Thomas

    While nanoparticles are a natural byproduct of combustion and a number of natural processes, engineered nanoparticles have only recently entered the consumer market. This motivates the development of methods for studying their effects on human cells, thereby indicating how larger models such as animals and humans might react to them. This research develops a method to mechanically characterize cellular traction forces as a measure of exposure to nanoparticles. To do this, 1microm micropillar molds were fabricated in silicon wafers using smooth sidewall reactive ion plasma etching technologies. Polydimethylsiloxane (PDMS), was cured inside the silicon molds, subsequently treated for cell culture and used to measure cellular traction forces over time in live cell time-lapse experiments. For the first time, transmitted light was used to visualize the PDMS micropillars; a force resolution of 5.6 +/-2.1nN was achieved across all experiments using a standard Olympus IX81 confocal microscope affixed with a 60x NA2.1 objective. To initiate cellular movement, monocyte chemoattractant protein (MCP-1) was conjugated to 1microm latex beads. The effects of 40nm silver nanoparticle exposures were quantified using the micropillar array. Changes in cellular behavior between the control group and cells exposed to nanosilver were not significant, although a comparison between the 5microg/ml and 10microg/ml nanosilver concentrations yielded strong significance using a 2 sided Students t test.

  5. Neural network-based voltage regulator for an isolated asynchronous generator supplying three-phase four-wire loads

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bhim; Kasal, Gaurav Kumar [Department of Electrical Engineering, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi 110016 (India)

    2008-06-15

    This paper deals with a neural network-based solid state voltage controller for an isolated asynchronous generator (IAG) driven by constant speed prime mover like diesel engine, bio-gas or gasoline engine and supplying three-phase four-wire loads. The proposed control scheme uses an indirect current control and a fast adaptive linear element (adaline) based neural network reference current extractor, which extracts the real positive sequence current component without any phase shift. The neutral current of the source is also compensated by using three single-phase bridge configuration of IGBT (insulated gate bipolar junction transistor) based voltage source converter (VSC) along-with single-phase transformer having self-supported dc bus. The proposed controller provides the functions as a voltage regulator, a harmonic eliminator, a neutral current compensator, and a load balancer. The proposed isolated electrical system with its controller is modeled and simulated in MATLAB along with Simulink and PSB (Power System Block set) toolboxes. The simulated results are presented to demonstrate the capability of an isolated asynchronous generating system driven by a constant speed prime mover for feeding three-phase four-wire loads. (author)

  6. ON THE ISSUE OF VECTOR CONTROL OF THE ASYNCHRONOUS MOTORS

    Directory of Open Access Journals (Sweden)

    B. I. Firago

    2015-01-01

    Full Text Available The paper considers the issue of one of the widespread types of vector control realization for the asynchronous motors with a short-circuited rotor. Of all more than 20 vector control types known presently, the following are applied most frequently: direct vector control with velocity pickup (VP, direct vector control without VP, indirect vector control with VP and indirect vector control without VP. Despite the fact that the asynchronous-motor indirect vector control without VP is the easiest and most spread, the absence of VP does not allow controlling the motor electromagnetic torque at zero velocity. This is the reason why for electric motor drives of such requirements they utilize the vector control with a velocity transducer. The systems of widest dissemination became the direct and indirect vector control systems with X-axis alignment of the synchronously rotating x–y-coordinate frame along the rotor flux-linkage vector inasmuch as this provides the simplest correlations for controlling variables. Although these two types of vector control are well presented in literature, a number of issues concerning their realization and practical application require further elaboration. These include: the block schemes adequate representation as consisted with the modern realization of vector control and clarification of the analytical expressions for evaluating the regulator parameters.The authors present a technique for evaluating the dynamics of an asynchronous electric motor drive with direct vector control and x-axis alignment along the vector of rotor flux linkage. The article offers a generalized structure of this vector control type with detailed description of its principal blocks: controlling system, frequency converter, and the asynchronous motor.The paper presents a direct vector control simulating model developed in the MatLab environment on the grounds of this structure. The authors illustrate the described technique with the results

  7. A new asynchronous parallel algorithm for inferring large-scale gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Xiangyun Xiao

    Full Text Available The reconstruction of gene regulatory networks (GRNs from high-throughput experimental data has been considered one of the most important issues in systems biology research. With the development of high-throughput technology and the complexity of biological problems, we need to reconstruct GRNs that contain thousands of genes. However, when many existing algorithms are used to handle these large-scale problems, they will encounter two important issues: low accuracy and high computational cost. To overcome these difficulties, the main goal of this study is to design an effective parallel algorithm to infer large-scale GRNs based on high-performance parallel computing environments. In this study, we proposed a novel asynchronous parallel framework to improve the accuracy and lower the time complexity of large-scale GRN inference by combining splitting technology and ordinary differential equation (ODE-based optimization. The presented algorithm uses the sparsity and modularity of GRNs to split whole large-scale GRNs into many small-scale modular subnetworks. Through the ODE-based optimization of all subnetworks in parallel and their asynchronous communications, we can easily obtain the parameters of the whole network. To test the performance of the proposed approach, we used well-known benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge (DREAM, experimentally determined GRN of Escherichia coli and one published dataset that contains more than 10 thousand genes to compare the proposed approach with several popular algorithms on the same high-performance computing environments in terms of both accuracy and time complexity. The numerical results demonstrate that our parallel algorithm exhibits obvious superiority in inferring large-scale GRNs.

  8. 直供方式下牵引变电所轨地回流研究%Research on Return Current to Traction Substation of TRNF Traction Network

    Institute of Scientific and Technical Information of China (English)

    李良威; 楚振宇; 邓云川

    2012-01-01

    Research purposes; The real tests and simulation analysis were made for the return current to the traction substation of TRNF traction network for passenger dedicated line to know the regulation of the traction return current to the traction substation of the TRNF traction network for guiding the design work. Research conclusions:This paper analyzes the principle of the traction return system of TRNF traction network. From the simulation calculation and analysis of the tested data of the return current to the Chongshan substation of the TRNF traction network with return wire for the Chengdu - Dujiangyan Passenger Dedicated Line, it can be seen using the TRNF traction network with return wire can significantly improve the distribution form of the return current system, reduce the proportion of the return current of the rail - earth and cut the impacts on the traction power supply equipment and communications signals equipments. Thus it can provide the design basis for selection of the equipments for the substation and communications signaling systems.%研究目的:通过对客运专线采用的带回流线的直供方式下牵引变电所轨地回流的实测和仿真分析,对牵引变电所处牵引回流规律获得认识,有利于指导设计工作.研究结论:本文分析了直供方式下牵引回流系统的原理,针对新建客运专线成都至都江堰铁路采用的带回流线的直供方式,通过对崇山变电所轨地回流系统的仿真计算和实测数据分析,得出采用带回流线的直供方式,可以明显改善回流系统的分配方式,减少轨地回流所占的比例,降低对牵引供电设备和通信信号设备的影响,并由此可以为牵引供变电和信号系统的设备选型提供设计依据.

  9. 面向地铁车辆牵引电机的车载变流系统设计%Design of converter system for the subway traction motor

    Institute of Scientific and Technical Information of China (English)

    方晓; 王丹; 申天亮; 马东辉

    2015-01-01

    In order to get good static and dynamic performance of metro traction motor, so as to satisfy the requirement of metro vehicle transport system, the indirect vector control strategy and the framework of DSP+FPGA are adopted by the converter system for the subway traction motor designed in this paper, according to the transient equivalent model of the asynchronous motor. The Matlab simulation and the experiment platform test prove that the system runs stably with smooth motor starting and fast torque dynamic response.%为使地铁牵引电机获得良好的静态和动态性能,从而满足地铁车辆牵引传动系统需求,文章提出的面向地铁车辆牵引电机的车载变流系统基于异步电机动态等效模型,采用间接矢量控制策略和DSP+FPGA的基本构架。通过Matlab仿真和搭建实验平台试验,证明系统运行稳定,且电机起动平滑,转矩动态响应快。

  10. [Evaluation of the effects of pulling angle and force on intermittent cervical traction with the Saunder's Halter].

    Science.gov (United States)

    Hseuh, T C; Ju, M S; Chou, Y L

    1991-12-01

    Intermittent cervical traction with proper angle and force is an effective treatment for cervical syndrome. The goals of therapy are effective traction for the affected segments without further damage to the soft tissue. The purposes of this study were to find the traction angle and force which results in the best therapeutic effect. The effect of cervical traction was evaluated by cervical roentgenography, by examining the distance of the posterior margin of the intervertebral space. For a study of the proper angle of traction, intermittent cervical traction was applied to 20 healthy normal volunteers in a supine position with a constant traction force of 15 kgf. The traction lasted for 8 seconds followed by unloading for 4 seconds and the application was alternated after 10 minutes. The elongated gaps of the posterior vertebral margins obtained from the different neck flexion angles of 35, 30, 25, 20 and 15 degrees were compared. Traction of under 30 degrees was longest for the levels of C4- 5 and C5-6. For the C6-7 and C7-T1 levels, traction was longest under 35 degrees. For study of the minimal effective traction force, the same procedures of intermittent cervical traction were applied to another 15 healthy normal volunteers, except the neck was fixed in a flexion of 35 degrees, and the traction force was 9, 12, 15 and 18 kgf. The best results were noted with a traction force of 15 or 18 kgf. However, there were more complaints of neck discomfort after traction with a force of 18 kgf.

  11. Novel Transverse Flux Machine for Vehicle Traction Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Z.; Ahmed, A.; Husain, I.; Muljadi, E.

    2015-04-02

    A novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.

  12. Brachial plexus injury: the London experience with supraclavicular traction lesions.

    Science.gov (United States)

    Birch, Rolfe

    2009-01-01

    In this article, the author details the experiences of his hospital and other London hospitals in treating brachial plexus injury. As noted, important advances have been made in methods of diagnosis and repair. Myelography was replaced by CT scan and later by MRI. Among the topics the author explores are diagnosis (including pain, the presence or absence of the Tinel sign, and the irradiation of pins and needles) and the principles of repair. The author emphasizes that it is imperative that ruptured nerves be repaired as soon as possible, with the closed traction lesion coming, in urgency, close behind reattachment of the amputated hand or repair of a great artery and a trunk nerve in the combined lesion. Finally, the article concludes that the surgeon must be actively engaged in the whole process of rehabilitation and treatment of pain. This is part of a Point-Counterpoint discussion with Dr. David G. Kline's presentation of "A Personal Experience."

  13. Initial experience with ocriplasmin in the treatment of vitreomacular traction

    Directory of Open Access Journals (Sweden)

    José Maurício Botto de Barros Garcia

    2016-04-01

    Full Text Available ABSTRACT This study aimed to report the clinical and structural outcomes of intravitreal ocriplasmin in the treatment of vitreomacular interface disorders in two tertiary centers in Brazil. A retrospective study was performed by reviewing medical records and spectral domain optical coherence tomography (SD-OCT findings of seven patients who were treated with a single ocriplasmin injection. A total of 57.14% of patients achieved resolution of vitreomacular traction as evidenced by SD-OCT. Regarding our functional results, 87.71% maintained or improved visual acuity after follow-up. To the best of our knowledge, this is the first study reporting initial results of ocriplasmin therapy in Brazil.

  14. Single-incision laparoscopic splenectomy with innovative gastric traction suture

    Directory of Open Access Journals (Sweden)

    Srikanth G

    2011-01-01

    Full Text Available Laparoscopic splenectomy is now the gold standard for patients with idiopathic thrombocytopenic purpura (ITP undergoing splenectomy. There are a few reports in literature on single-incision laparoscopic (SIL splenectomy. Herein, we describe a patient undergoing SIL splenectomy for ITP without the use of a disposable port device. We report a 20-year-old female patient with steroid-refractory ITP having a platelet count of 14,000/cmm who underwent a SIL splenectomy. Dissection was facilitated by the use of a single articulating grasper and a gastric traction suture and splenic vessels were secured at the hilum with an endo-GIA stapler. She made an uneventful postoperative recovery and was discharged on the second postoperative day. She is doing well with no visible scar at 8-month follow-up.

  15. Lumbar spine traction: evaluation of effects and recommended application for treatment.

    Science.gov (United States)

    Krause, M; Refshauge, K M; Dessen, M; Boland, R

    2000-05-01

    Despite the widespread use of traction, little is known of the mode of effect, and application remains largely anecdotal. The efficacy of traction is also unclear because of generally poor design of the clinical trials to date, and because subgroups of patients most likely to benefit have not been specifically studied. These observations prompted this review, the purposes of which are to evaluate the mechanisms by which traction may provide benefit and to provide rational guidelines for the clinical application of traction. Traction has been shown to separate the vertebrae and it appears that large forces are not required. Vertebral separation could provide relief from radicular symptoms by removing direct pressure or contact forces from sensitised neural tissue. Other mechanisms proposed to explain the effects of traction (e.g. reduction of disc protrusion or altered intradiscal pressure) have been shown not to occur. We conclude that traction is most likely to benefit patients with acute (less than 6 weeks' duration) radicular pain with concomitant neurological deficit. The apparent lack of a dose-response relationship suggests that low doses are probably sufficient to achieve benefit.

  16. Traction bronchiectasis in cryptogenic fibrosing alveolitis: associated computed tomographic features and physiological significance

    Energy Technology Data Exchange (ETDEWEB)

    Desai, Sujal R. [Department of Radiology, King' s College Hospital, Denmark Hill, SE5 9RS, London (United Kingdom); Wells, Athol U.; Bois, Roland M. du [Interstitial Lung Disease Unit, Royal Brompton Hospital, Emmanuel Kaye Building, Manresa Road, Fulham, SW6 6LR, London (United Kingdom); Rubens, Michael B.; Hansell, David M. [Department of Radiology, Royal Brompton Hospital, Sydney Street, SW3 6NP, London (United Kingdom)

    2003-08-01

    Our objective was to evaluate the associated CT features and physiological consequences of traction bronchiectasis in patients with cryptogenic fibrosing alveolitis (CFA). The CT scans of 212 patients with CFA (158 men, 54 women; mean age 62.2{+-}10.6 years) were evaluated independently by two observers. The extent of fibrosis, the proportions of a reticular pattern and ground-glass opacification and the extent of emphysema were scored at five levels. The predominant CT pattern, coarseness of a reticular pattern and severity of traction bronchiectasis were graded semiquantitatively. Physiological indices were correlated with CT features. There was traction bronchiectasis on CT in 202 of 212 (95%) patients. Increasingly severe traction bronchiectasis was independently associated with increasingly extensive CFA (p<0.0005), a coarser reticular pattern (p<0.001), a lower proportion of ground-glass opacification (p<0.005) and less extensive emphysema (p<0.0005). Increasingly severe traction bronchiectasis was independently related to depression of DL{sub CO} (p<0.005), FVC (p=0.02) and pO{sub 2} (p<0.0005), but not indices of air-flow obstruction. In CFA, traction bronchiectasis increases with more extensive disease, a lower proportion of ground-glass opacification and a coarser reticular pattern, but it decreases with concurrent emphysema. Increasingly severe traction bronchiectasis is associated with additional physiological impairment for a given extent of pulmonary fibrosis and emphysema. (orig.)

  17. [The effect of halo-gravity traction in the preoperative treatment of neuromuscular scoliosis].

    Science.gov (United States)

    Flierl, S; Carstens, C

    1997-01-01

    The purpose of this study is to evaluate the influence of halo-gravity-traction on paralytic scoliosis in various neurologic diseases. Between 1980 and 1993 preoperative halo-gravity-traction was applied in 32 patients with paralytic scoliosis (23 patients with myelomeningocele, 6 patients with poliomyelitis, 3 patients with cerebral palsy). In the myelomeningocele group the average curvature before treatment was 97.8 degrees, after surgery 45.1 degrees; which is an improvement of 53.9%. Halo-gravity-traction accounted for 12.8% improvement. In the poliomyelitis group the average curvature before treatment was 104.3 degrees, after surgery 58.0 degrees; which is an improvement of 44.4%. Halo-gravity-traction accounted for 16.9% improvement. In the cerebral palsy group the average curvature before treatment was 75.0 degrees, after surgery 39.0 degrees; which is an improvement of 48.0%. Halo-gravity-traction accounted for -2.7% improvement. If there is an effect the question remains, whether this will have consequences for the surgical outcome. The comparison between good and bad responders with the surgical result shows, that this result is independent of the halo-gravity-traction. From this results we draw the conclusion, that preoperative halo-gravity-traction can not be recommended in paralytic scoliosis.

  18. Analysis of electromyographic activities of the lumbar erector spinae caused by inversion traction.

    Science.gov (United States)

    Kim, Chung Yoo; Kang, Jong Ho

    2016-04-01

    [Purpose] The purpose of this study was to analyze changes in the electromyographic activities of the lumbar erector spinae caused by inversion traction in order to verify the relaxation effect. [Subjects and Methods] The subjects included 60 healthy male adults who were equally and randomly assigned to a 30-30° group, a 30-60° group, and a 60-60° group. Inversion traction was performed for six minutes, and the electromyographic activities of the lumbar erector spinae (L2, L4) were measured before and after inversion traction. [Results] The root mean square values at the L2 and L4 levels on both sides were statistically significantly higher after inversion traction compared with before inversion traction. Before inversion traction, the root mean square values at the L2 and L4 levels on both sides in the 30-60° group and 60-60° group were significantly higher than those in the 30-30° group, while the root mean square values at the L2 and L4 levels on both sides showed no significant differences between the groups before inversion traction. [Conclusion] The findings of this study indicated that IT is more likely to elicits an increase in muscle tension and prevent relaxation of the lumbar erector spinae.

  19. Halo Gravity Traction Is Associated with Reduced Bone Mineral Density of Patients with Severe Kyphoscoliosis

    Directory of Open Access Journals (Sweden)

    Xiao Han

    2016-01-01

    Full Text Available Background. Halo gravity traction (HGT is one of the most commonly used perioperative techniques for the treatment of severe kyphoscoliosis. This study was to explore the influence of HGT on the BMD of these patients. Methods. Patients with severe kyphoscoliosis treated by preoperative HGT for at least 2 months were included. Patients’ BMD were assessed by dual-energy X-ray absorptiometry at lumbar spine (LS, L2–L4 and femur neck (FN of the nondominant side. The weight and duration of traction, as well as baseline characteristics, were recorded. Results. Twenty patients were recruited. The average traction duration was 77.9±13.0 days while the mean traction weight was 39.9%±11.1% of total body weight. Remarkable decrease of BMD was observed at LS of 17 (85% patients and at FN of 18 (90% patients. After HGT, 75% of patients were found to have osteoporosis, the incidence of which was significantly higher than that before HGT (35%. The correlation analysis revealed BMD reduction was only significantly correlated with the traction duration. Conclusions. The current study showed that preoperative HGT can have obvious impact on the BMD. The BMD reduction is associated with traction duration, suggesting that long traction duration may bring more bone mineral loss.

  20. Spinal traction promotes molecular transportation in a simulated degenerative intervertebral disc model.

    Science.gov (United States)

    Kuo, Ya-Wen; Hsu, Yu-Chun; Chuang, I-Ting; Chao, Pen-Hsiu Grace; Wang, Jaw-Lin

    2014-04-20

    Biomechanical experiment using an in situ porcine model. To find the effect of traction treatment on annulus microstructure, molecular convection, and cell viability of degraded discs. Spinal traction is a conservative treatment for disc disorders. The recognized biomechanical benefits include disc height recovery, foramen enlargement, and intradiscal pressure reduction. However, the influence of traction treatment on annulus microstructure, molecular transportation, and cell viability of degraded discs has not been fully investigated. A total of 48 thoracic discs were dissected from 8 porcine spines (140 kg, 6-month old) within 4 hours after killing them and then divided into 3 groups: intact, degraded without traction, and degraded with traction. Each disc was incubated in a whole-organ culture system and subjected to diurnal loadings for 7 days. Except for the intact group, discs were degraded with 0.5 mL of trypsin on day 1 and a 5-hour fatigue loading on day 2. From day 4 to day 6, half of the degraded discs received a 30-minute traction treatment per day (traction force: 20 kg; loading: unloading = 30 s: 10 s). By the end of the incubation, the discs were inspected for disc height loss, annulus microstructure, molecular (fluorescein sodium) intensity, and cell viability. Collagen fibers were crimped and delaminated, whereas the pores were occluded in the annulus fibrosus of the degraded discs. Molecular transportation and cell viability of the discs decreased after matrix degradation. With traction treatment, straightened collagen fibers increased within the degraded annulus fibrosus, and the annulus pores were less occluded. Both molecular transportation and cell viability increased, but not to the intact level. Traction treatment is effective in enhancing nutrition supply and promoting disc cell proliferation of the degraded discs. N/A.

  1. MODES OF OPERATION OF THE SYSTEM OF TRACTION POWER AC USING REACTIVE POWER COMPENSATION DEVICES

    Directory of Open Access Journals (Sweden)

    I.V. Domanskyi

    2015-06-01

    Full Text Available The paper presents a systematic analysis of existing methods of reactive power compensation. The study of operating modes of the systems external and traction power supply is carried out. The methodology for selecting promising compensation schemes and energy-saving in the traction networks AC electrified railway lines is offered. The comparative evaluation of prospective controlled compensation devices shows that use of seamlessly adjustable devices with unregulated condensing the battery and with parallel translator regulated with thyristor unit and with filters to reduce harmonics bond to the large capital investments. For traction networks of domestic railways payback period is more than 10-15 years. The most promising for traction power supply today is a stepwise adjustable devices of reactive power compensation. For the efficient allocation of investments in programs and projects of modernization of system traction power supply developed by the methodology of selecting parameters and places placement devices transverse compensation in the system traction power supply, which is based on the use of software systems with imitation of interconnected instant circuits moving loads of electric rolling stock. Based on the results of multiple calculations full factor experiment when simulating work of the systems traction power supply during the day marked the most influencing factors on energy-saving in process freight on electric traction and established the extent of their influence. These include the overflows of power, the resistance of traction network, reactive power compensation, power supply circuits and the organization of trains. Innovative technologies energy-saving railways from positions of consideration their close connection with the systems external power supply are proposed.

  2. CALCULATION OF A MECHANICAL CHARACTERISTIC OF ELECTRIC TRACTION MOTOR OF ELECTRIC VEHICLE

    Directory of Open Access Journals (Sweden)

    Phuong Le Ngo

    2017-01-01

    Full Text Available The traction characteristic of an electric vehicle is the main characteristic of mechanical system that reflects its key performance indicators. Implementation of the traction characteristic is based on controlling angular speed and torque of electric traction motor in an automatic control system. The static mechanical characteristic of an electric traction motor in an automatic control system is the most important characteristic that determines weight, size and operating characteristics of an electric traction motor and serves as the basis for design. The most common variants of constructive implementation of a traction electric drive are analyzed, and a scheme is chosen for further design. Lagrange’s equation for electric mechanical system with one degree of freedom is written in generalized coordinates. In order to determine the generalized forces, elementary operation of all moments influencing on a moving car has been calculated. The resulting equation of motion of the electric vehicle corresponding to the design scheme, as well as the expressions for calculation of characteristic points of static mechanical characteristics of traction motor (i.e. the maximum and minimum time, minimum power are obtained. In order to determine the nominal values of the angular velocity and the power of electric traction motor, a method based on ensuring the movement of the vehicle in the standard cycle has been developed. The method makes it possible to calculate characteristic points of the mechanical characteristic with the lowest possible power rating. The algorithm for calculation of mechanical characteristics of the motor is presented. The method was applied to calculate static mechanical characteristic of an electric traction motor for a small urban electric truck.

  3. Function of Train Traction Department and Railway Vehicles in Logistic Centres

    Directory of Open Access Journals (Sweden)

    Velimir Kolar

    2007-05-01

    Full Text Available The increasing globalization has spread the production locationsto every part of the world thus increasing even more therole of transport in determining the price and quality of a product.Therefore, the producers and carriers join together moreand more frequently through the supply chains. Railway carriershave a very significant role in supply chains, both throughorganization of transport and forming the trains as final products,and through forming the logistic centres. Logistic centresare the starting and the final railway stations but also the meetingpoints of the national carrier with other carriers (sea, road,river as well as other railway carriers and they also represent informationcentres. For the quality of service at logistic centres, itis important to have well organized operation of train traction.In order to keep up the regulmity of trains and the quality oftransport at logistic centres, among other things, it is necessaryto provide an optimal number of locomotives and to providethe technical inspection place. Special attention should be paidto the organization of work peiformed by the engine staff At logisticcentres it is possible to organize high-quality technical inspectionof wagons thus increasing the traffic safety.

  4. 铁路机车异步牵引电动机的轴承结构设计%Bearing Structure Design of Railway Locomotive Asynchronous Traction Motor

    Institute of Scientific and Technical Information of China (English)

    李进泽

    2010-01-01

    对于结构简单、维护量少的铁路机车异步牵引电动机来说,作为其关键部件之一的轴承往往是其中的一个薄弱点,其运转情况的好坏在很大程度上直接影响异步牵引电动机的运行可靠性.因此,在电机设计时,必须合理设计其轴承结构,包括选择合适的轴承、设计正确的润滑系统和可靠的密封结构等.

  5. 内燃机车异步牵引电动机的设计探讨%Discussion on Design of Asynchronous Traction Motor for Diesel Locomotive

    Institute of Scientific and Technical Information of China (English)

    孟语灵

    2009-01-01

    对内燃机车异步牵引电动机的设计进行了分析研究,结合内燃机车运行的特点,从电机运行的特性曲线、牵引变流器及其控制系统对电机的影响、结构参数与设计特点、关键材料的选取等方面进行了较详细的阐述.提出了合理设计和整体优化异步牵引电动机的方案.

  6. Surgical management of retinal diseases: proliferative diabetic retinopathy and traction retinal detachment.

    Science.gov (United States)

    Cruz-Iñigo, Yousef J; Acabá, Luis A; Berrocal, Maria H

    2014-01-01

    Current indications for pars plana vitrectomy in patients with proliferative diabetic retinopathy (PDR) include vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), diabetic macular edema associated with posterior hyaloidal traction, and anterior segment neovascularization with media opacities. This chapter will review the indications, surgical objectives, adjunctive pharmacotherapy, microincision surgical techniques, and outcomes of diabetic vitrectomy for PDR, TRD, and CTRRD. With the availability of new microincision vitrectomy technology, wide-angle microscope viewing systems, and pharmacologic agents, vitrectomy can improve visual acuity and achieve long-term anatomic stability in eyes with severe complications from PDR.

  7. Traction Control of Electric Vehicles Using Sliding-Mode Controller with Tractive Force Observer

    Directory of Open Access Journals (Sweden)

    Suwat Kuntanapreeda

    2014-01-01

    Full Text Available Traction control is an important element in modern vehicles to enhance drive efficiency, safety, and stability. Traction is produced by friction between tire and road, which is a nonlinear function of wheel slip. In this paper, a sliding-mode control approach is used to design a robust traction controller. The control objective is to operate vehicles such that a desired wheel slip ratio is achieved. A nonlinearity observer is employed to estimate tire tractive forces, which are used in the control law. Simulation and experimental results have illustrated the success of the proposed observer-based controller.

  8. Asynchronous parallel generating set search for linearly-constrained optimization.

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, Tamara G.; Griffin, Joshua; Lewis, Robert Michael

    2007-04-01

    We describe an asynchronous parallel derivative-free algorithm for linearly-constrained optimization. Generating set search (GSS) is the basis of ourmethod. At each iteration, a GSS algorithm computes a set of search directionsand corresponding trial points and then evaluates the objective function valueat each trial point. Asynchronous versions of the algorithm have been developedin the unconstrained and bound-constrained cases which allow the iterations tocontinue (and new trial points to be generated and evaluated) as soon as anyother trial point completes. This enables better utilization of parallel resourcesand a reduction in overall runtime, especially for problems where the objec-tive function takes minutes or hours to compute. For linearly-constrained GSS,the convergence theory requires that the set of search directions conform to the3 nearby boundary. The complexity of developing the asynchronous algorithm forthe linearly-constrained case has to do with maintaining a suitable set of searchdirections as the search progresses and is the focus of this research. We describeour implementation in detail, including how to avoid function evaluations bycaching function values and using approximate look-ups. We test our imple-mentation on every CUTEr test problem with general linear constraints and upto 1000 variables. Without tuning to individual problems, our implementationwas able to solve 95% of the test problems with 10 or fewer variables, 75%of the problems with 11-100 variables, and nearly half of the problems with100-1000 variables. To the best of our knowledge, these are the best resultsthat have ever been achieved with a derivative-free method. Our asynchronousparallel implementation is freely available as part of the APPSPACK software.4

  9. Creating video-annotated discussions: An asynchronous alternative

    Directory of Open Access Journals (Sweden)

    Craig D. Howard

    2010-01-01

    Full Text Available In this article the authors illustrate the design and development of a pedagogical intervention using video annotations in a pre-service teacher education courrse. An annotation platform was selected and video was shot to create a video backdrop on which asynchronous discussions would take place. The article addresses design considerations in the selection of video, the editing process, and the development of a tutorial to lead learners through their first experience with this form of discussion. Learner participation samples were collected, and an analysis of the design process concludes the article.

  10. Positive semidefinite integrated covariance estimation, factorizations and asynchronicity

    DEFF Research Database (Denmark)

    Sauri, Orimar; Lunde, Asger; Laurent, Sébastien;

    2017-01-01

    An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization of the covariance matrix in order to exploit the heterogeneity in trading intensities to estimate the different parameters sequentially with as many...... observations as possible. The estimator is positive semidefinite by construction. We derive asymptotic results and confirm their good finite sample properties by means of a Monte Carlo simulation. In the application we forecast portfolio Value-at-Risk and sector risk exposures for a portfolio of 52 stocks. We...

  11. Wind Generator Stabilization with Doubly-Fed Asynchronous Machine

    Institute of Scientific and Technical Information of China (English)

    WU Li; WANG Zhi-xin

    2007-01-01

    This paper investigates the function of doubly-fed asynchronous machine(DASM) with emphasis placed on its ability to the stabilization of the power system including wind generators. P(active power) and Q(reactive power) compensation from DASM can be regulated independently through secondary-excitation controlling. Simulation results by power system computer aided design(PSCAD) show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures. Comparison studies have also been performed between wind turbine pitch control and proposed method.

  12. Faculty development and mentorship using selected online asynchronous teaching strategies.

    Science.gov (United States)

    Vitale, Anne T

    2010-12-01

    The use of distance learning continues to improve accessibility to nursing education programs, yet online teaching remains an intimidating experience for novice educators. An emerging role in professional faculty development is the online educator, who serves as a mentor for novice faculty. This article presents the necessary elements to plan, organize, and manage asynchronous online courses, especially for novice educators and online faculty mentors. Course engagement and faculty-student online communication strategies are explored using examples. Threaded discussion strategies for engaging students in active, collaborative learning are discussed using specific examples. A threaded discussion grading rubric is included. Strategies to sustain interactive learning and evaluate student learning using examples are offered.

  13. A Verification System for Distributed Objects with Asynchronous Method Calls

    Science.gov (United States)

    Ahrendt, Wolfgang; Dylla, Maximilian

    We present a verification system for Creol, an object-oriented modeling language for concurrent distributed applications. The system is an instance of KeY, a framework for object-oriented software verification, which has so far been applied foremost to sequential Java. Building on KeY characteristic concepts, like dynamic logic, sequent calculus, explicit substitutions, and the taclet rule language, the system presented in this paper addresses functional correctness of Creol models featuring local cooperative thread parallelism and global communication via asynchronous method calls. The calculus heavily operates on communication histories which describe the interfaces of Creol units. Two example scenarios demonstrate the usage of the system.

  14. Negative circuits and sustained oscillations in asynchronous automata networks

    CERN Document Server

    Richard, Adrien

    2009-01-01

    The biologist Ren\\'e Thomas conjectured, twenty years ago, that the presence of a negative feedback circuit in the interaction graph of a dynamical system is a necessary condition for this system to produce sustained oscillations. In this paper, we state and prove this conjecture for asynchronous automata networks, a class of discrete dynamical systems extensively used to model the behaviors of gene networks. As a corollary, we obtain the following fixed point theorem: given a product $X$ of $n$ finite intervals of integers, and a map $F$ from $X$ to itself, if the interaction graph associated with $F$ has no negative circuit, then $F$ has at least one fixed point.

  15. A wavelet approach to binary blackholes with asynchronous multitasking

    Science.gov (United States)

    Lim, Hyun; Hirschmann, Eric; Neilsen, David; Anderson, Matthew; Debuhr, Jackson; Zhang, Bo

    2016-03-01

    Highly accurate simulations of binary black holes and neutron stars are needed to address a variety of interesting problems in relativistic astrophysics. We present a new method for the solving the Einstein equations (BSSN formulation) using iterated interpolating wavelets. Wavelet coefficients provide a direct measure of the local approximation error for the solution and place collocation points that naturally adapt to features of the solution. Further, they exhibit exponential convergence on unevenly spaced collection points. The parallel implementation of the wavelet simulation framework presented here deviates from conventional practice in combining multi-threading with a form of message-driven computation sometimes referred to as asynchronous multitasking.

  16. Adding effect of current displacement and magnetic circuit saturation in an asynchronous motor mathematical model

    Directory of Open Access Journals (Sweden)

    I.A. Tsodik

    2014-04-01

    Full Text Available A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.

  17. The design of an asynchronous Tiny RISC TM/TR4101 microprocessor core

    DEFF Research Database (Denmark)

    Christensen, Kåre Tais; Jensen, P.; Korger, P.

    1998-01-01

    This paper presents the design of an asynchronous version of the TR4101 embedded microprocessor core developed by LSI Logic Inc. The asynchronous processor, called ARISC, was designed using the same CAD tools and the same standard cell library that was used to implement the TR4101. The paper repo...

  18. The Key Implementation Technology of Client/Server's Asynchronous Communication Programs

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper introduces the implementation method,key technology and flowchart of Client/Server's asynchronous communication programs on Linux or Unix,and further explains a few problems to which should pay attention for improving CPU's efficiency in implementing asynchronous communication programs.

  19. Behavioral Synthesis of Asynchronous Circuits Using Syntax Directed Translation as Backend

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard; Sparsø, Jens; Madsen, Jan

    2009-01-01

    of syntax directed translation, and which allows the designer to perform automatic design space exploration guided by area or speed constraints. The paper presents an asynchronous implementation template consisting of a data-path and a control unit and its implementation using the asynchronous hardware...

  20. Using Television Sitcoms to Facilitate Asynchronous Discussions in the Online Communication Course

    Science.gov (United States)

    Tolman, Elizabeth; Asbury, Bryan

    2012-01-01

    Asynchronous discussions are a useful instructional resource in the online communication course. In discussion groups students have the opportunity to actively participate and interact with students and the instructor. Asynchronous communication allows for flexibility because "participants can interact with significant amounts of time between…

  1. Optimization design of a full asynchronous pipeline circuit based on null convention logic

    Energy Technology Data Exchange (ETDEWEB)

    Guan Xuguang; Zhou Duan; Yang Yintang, E-mail: guanxuguang_5@126.co [Institute of Microelectronics, Xidian University, Xi' an 710071 (China)

    2009-07-15

    This paper proposes a new optimization method to improve the performance of a null convention logic asynchronous pipeline. Parallel combinational logic modules in the pipelines can work alternately in null and data cycles by using a parallel processing mode. The complete waiting time for both null and data signals of combinational logic output in previous asynchronous register stage is reduced by decoupling the output from combinational logic modules. Performance penalty brought by null cycle is reduced while the data processing capacity is increased. The novel asynchronous pipeline based on asynchronous full adders with different bit widths as asynchronous combination logic modules is simulated using 0.18-{mu}m CMOS technology. Based on 6 bits asynchronous adder as asynchronous combination logic modules, the simulation result of this new pipeline proposal demonstrates a high throughput up to 72.4% improvement with appropriate power consumption. This indicates the new design proposal is preferable for high-speed asynchronous designs due to its high throughput and delay-insensitivity.

  2. Exploring the Effect of Scripted Roles on Cognitive Presence in Asynchronous Online Discussions

    Science.gov (United States)

    Olesova, Larisa; Slavin, Margaret; Lim, Jieun

    2016-01-01

    The purpose of this study was to identify the effect of scripted roles on students' level of cognitive presence in asynchronous online threaded discussions. A quantitative content analysis was used to investigate: (1) what level of cognitive presence is achieved by students' assigned roles in asynchronous online discussions; (2) differences…

  3. A Scheduling Discipline for Latency and Bandwidth Guarantees in Asynchronous Network-on-Chip

    DEFF Research Database (Denmark)

    Bjerregaard, Tobias; Sparsø, Jens

    2005-01-01

    Guaranteed services (GS) are important in that they provide predictability in the complex dynamics of shared communication structures. This paper discusses the implementation of GS in asynchronous Network-on-Chip. We present a novel scheduling discipline called Asynchronous Latency Guarantee (ALG...

  4. Treatment of 150 Cases of Lumber Intervertebral Disk Displacement by Acupuncture plus Traction

    Institute of Scientific and Technical Information of China (English)

    CHEN Qing-bao; WU Xue-fei

    2003-01-01

    Needling Point Jiaji ( Ex-B 2), Dachangshu ( BL 25), Huantiao ( GB 30), Weizhong ( BL 40), and Yanglingquan (GB 34) etc with the cooperation of traction, treated lumbar intervertebral disk displacement.The effective rate was 91.3%.

  5. A rough terrain traction control technique for all-wheel-drive mobile robots

    National Research Council Canada - National Science Library

    Silva, Alexandre F. Barral; Santos, Auderi Vicente; Meggiolaro, Marco Antonio; Speranza Neto, Mauro

    2010-01-01

    ... - and guaranteeing an adequate trajectory and speed control while reducing the power requirements. Traction control of all-wheel-drive robots in rough terrain was originally motivated by space exploration, such as in the case of the Mars Exploration Rovers...

  6. Application on forced traction test in surgeries for orbital blowout fracture

    Directory of Open Access Journals (Sweden)

    Bao-Hong Han

    2014-05-01

    Full Text Available AIM: To discuss the application of forced traction test in surgeries for orbital blowout fracture.METHODS: The clinical data of 28 patients with reconstructive surgeries for orbital fracture were retrospectively analyzed. All patients were treated with forced traction test before/in/after operation. The eyeball movement and diplopia were examined and recorded pre-operation, 3 and 6mo after operation, respectively.RESULTS: Diplopia was improved in all 28 cases with forced traction test. There was significant difference between preoperative and post-operative diplopia at 3 and 6mo(PCONCLUSION: Forced traction test not only have a certain clinical significance in diagnosis of orbital blowout fracture, it is also an effective method in improving diplopia before/in/after operation.

  7. REGRESSION DEPENDENCE CONSTRUCTION METHODOLOGY FOR TRACTION CURVES USING LEAST SQUARE METHOD

    Directory of Open Access Journals (Sweden)

    V. Ravino

    2013-01-01

    Full Text Available   The paper presents a methodology that permits to construct regression dependences for traction curves of various tractors while using different operational backgrounds. The dependence construction process is carried out with the help of Microsoft Excel.

  8. Transcondylar traction as a closed reduction technique in vertically unstable pelvic ring disruption

    OpenAIRE

    Thaunat, M.; Laude, F.; Paillard, P.; Saillant, G.; Catonné, Y.

    2007-01-01

    Little information is provided in the literature describing an efficient reduction technique for pelvic ring disruption. The aim of this study is to assess the use of the transcondylar traction as a closed reduction technique for vertically unstable fracture-dislocations of the sacro-iliac joint. Twenty-four pelvic ring disruptions were treated with attempted closed reduction followed by percutaneous screw fixation. Transcondylar traction was used as a closed reduction technique. Closed reduc...

  9. Finite element analysis of traction force microscopy: influence of cell mechanics, adhesion, and morphology.

    Science.gov (United States)

    Zielinski, Rachel; Mihai, Cosmin; Kniss, Douglas; Ghadiali, Samir N

    2013-07-01

    The interactions between adherent cells and their extracellular matrix (ECM) have been shown to play an important role in many biological processes, such as wound healing, morphogenesis, differentiation, and cell migration. Cells attach to the ECM at focal adhesion sites and transmit contractile forces to the substrate via cytoskeletal actin stress fibers. This contraction results in traction stresses within the substrate/ECM. Traction force microscopy (TFM) is an experimental technique used to quantify the contractile forces generated by adherent cells. In TFM, cells are seeded on a flexible substrate and displacements of the substrate caused by cell contraction are tracked and converted to a traction stress field. The magnitude of these traction stresses are normally used as a surrogate measure of internal cell contractile force or contractility. We hypothesize that in addition to contractile force, other biomechanical properties including cell stiffness, adhesion energy density, and cell morphology may affect the traction stresses measured by TFM. In this study, we developed finite element models of the 2D and 3D TFM techniques to investigate how changes in several biomechanical properties alter the traction stresses measured by TFM. We independently varied cell stiffness, cell-ECM adhesion energy density, cell aspect ratio, and contractility and performed a sensitivity analysis to determine which parameters significantly contribute to the measured maximum traction stress and net contractile moment. Results suggest that changes in cell stiffness and adhesion energy density can significantly alter measured tractions, independent of contractility. Based on a sensitivity analysis, we developed a correction factor to account for changes in cell stiffness and adhesion and successfully applied this correction factor algorithm to experimental TFM measurements in invasive and noninvasive cancer cells. Therefore, application of these types of corrections to TFM

  10. Remanent cell traction force in renal vascular smooth muscle cells induced by integrin-mediated mechanotransduction.

    Science.gov (United States)

    Balasubramanian, Lavanya; Lo, Chun-Min; Sham, James S K; Yip, Kay-Pong

    2013-02-15

    It was previously demonstrated in isolated renal vascular smooth muscle cells (VSMCs) that integrin-mediated mechanotransduction triggers intracellular Ca(2+) mobilization, which is the hallmark of myogenic response in VSMCs. To test directly whether integrin-mediated mechanotransduction results in the myogenic response-like behavior in renal VSMCs, cell traction force microscopy was used to monitor cell traction force when the cells were pulled with fibronectin-coated or low density lipoprotein (LDL)-coated paramagnetic beads. LDL-coated beads were used as a control for nonintegrin-mediated mechanotransduction. Pulling with LDL-coated beads increased the cell traction force by 61 ± 12% (9 cells), which returned to the prepull level after the pulling process was terminated. Pulling with noncoated beads had a minimal increase in the cell traction force (12 ± 9%, 8 cells). Pulling with fibronectin-coated beads increased the cell traction force by 56 ± 20% (7 cells). However, the cell traction force was still elevated by 23 ± 14% after the pulling process was terminated. This behavior is analogous to the changes of vascular resistance in pressure-induced myogenic response, in which vascular resistance remains elevated after myogenic constriction. Fibronectin is a native ligand for α(5)β(1)-integrins in VSMCs. Similar remanent cell traction force was found when cells were pulled with beads coated with β(1)-integrin antibody (Ha2/5). Activation of β(1)-integrin with soluble antibody also triggered variations of cell traction force and Ca(2+) mobilization, which were abolished by the Src inhibitor. In conclusion, mechanical force transduced by α(5)β(1)-integrins triggered a myogenic response-like behavior in isolated renal VSMCs.

  11. Remanent cell traction force in renal vascular smooth muscle cells induced by integrin-mediated mechanotransduction

    OpenAIRE

    Balasubramanian, Lavanya; Lo, Chun-Min; Sham, James S. K.; Yip, Kay-Pong

    2013-01-01

    It was previously demonstrated in isolated renal vascular smooth muscle cells (VSMCs) that integrin-mediated mechanotransduction triggers intracellular Ca2+ mobilization, which is the hallmark of myogenic response in VSMCs. To test directly whether integrin-mediated mechanotransduction results in the myogenic response-like behavior in renal VSMCs, cell traction force microscopy was used to monitor cell traction force when the cells were pulled with fibronectin-coated or low density lipoprotei...

  12. A Predictive Model of Cell Traction Forces Based on Cell Geometry

    OpenAIRE

    Lemmon, Christopher A.; Romer, Lewis H

    2010-01-01

    Recent work has indicated that the shape and size of a cell can influence how a cell spreads, develops focal adhesions, and exerts forces on the substrate. However, it is unclear how cell shape regulates these events. Here we present a computational model that uses cell shape to predict the magnitude and direction of forces generated by cells. The predicted results are compared to experimentally measured traction forces, and show that the model can predict traction force direction, relative m...

  13. An Asynchronous Recurrent Network of Cellular Automaton-Based Neurons and Its Reproduction of Spiking Neural Network Activities.

    Science.gov (United States)

    Matsubara, Takashi; Torikai, Hiroyuki

    2016-04-01

    Modeling and implementation approaches for the reproduction of input-output relationships in biological nervous tissues contribute to the development of engineering and clinical applications. However, because of high nonlinearity, the traditional modeling and implementation approaches encounter difficulties in terms of generalization ability (i.e., performance when reproducing an unknown data set) and computational resources (i.e., computation time and circuit elements). To overcome these difficulties, asynchronous cellular automaton-based neuron (ACAN) models, which are described as special kinds of cellular automata that can be implemented as small asynchronous sequential logic circuits have been proposed. This paper presents a novel type of such ACAN and a theoretical analysis of its excitability. This paper also presents a novel network of such neurons, which can mimic input-output relationships of biological and nonlinear ordinary differential equation model neural networks. Numerical analyses confirm that the presented network has a higher generalization ability than other major modeling and implementation approaches. In addition, Field-Programmable Gate Array-implementations confirm that the presented network requires lower computational resources.

  14. Continuous EEG signal analysis for asynchronous BCI application.

    Science.gov (United States)

    Hsu, Wei-Yen

    2011-08-01

    In this study, we propose a two-stage recognition system for continuous analysis of electroencephalogram (EEG) signals. An independent component analysis (ICA) and correlation coefficient are used to automatically eliminate the electrooculography (EOG) artifacts. Based on the continuous wavelet transform (CWT) and Student's two-sample t-statistics, active segment selection then detects the location of active segment in the time-frequency domain. Next, multiresolution fractal feature vectors (MFFVs) are extracted with the proposed modified fractal dimension from wavelet data. Finally, the support vector machine (SVM) is adopted for the robust classification of MFFVs. The EEG signals are continuously analyzed in 1-s segments, and every 0.5 second moves forward to simulate asynchronous BCI works in the two-stage recognition architecture. The segment is first recognized as lifted or not in the first stage, and then is classified as left or right finger lifting at stage two if the segment is recognized as lifting in the first stage. Several statistical analyses are used to evaluate the performance of the proposed system. The results indicate that it is a promising system in the applications of asynchronous BCI work.

  15. Algebraic Number Precoded OFDM Transmission for Asynchronous Cooperative Multirelay Networks

    Directory of Open Access Journals (Sweden)

    Hua Jiang

    2014-01-01

    Full Text Available This paper proposes a space-time block coding (STBC transmission scheme for asynchronous cooperative systems. By combination of rotated complex constellations and Hadamard transform, these constructed codes are capable of achieving full cooperative diversity with the analysis of the pairwise error probability (PEP. Due to the asynchronous characteristic of cooperative systems, orthogonal frequency division multiplexing (OFDM technique with cyclic prefix (CP is adopted for combating timing delays from relay nodes. The total transmit power across the entire network is fixed and appropriate power allocation can be implemented to optimize the network performance. The relay nodes do not require decoding and demodulation operation, resulting in a low complexity. Besides, there is no delay for forwarding the OFDM symbols to the destination node. At the destination node the received signals have the corresponding STBC structure on each subcarrier. In order to reduce the decoding complexity, the sphere decoder is implemented for fast data decoding. Bit error rate (BER performance demonstrates the effectiveness of the proposed scheme.

  16. Asynchronously sampled blind source separation for coherent optical links

    Science.gov (United States)

    Detwiler, Thomas F.; Searcy, Steven M.; Stark, Andrew J.; Ralph, Stephen E.; Basch, Bert E.

    2011-01-01

    Polarization multiplexing is an integral technique for generating spectrally efficient 100 Gb/s and higher optical links. Post coherent detection DSP-based polarization demultiplexing of QPSK links is commonly performed after timing recovery. We propose and demonstrate a method of asynchronous blind source separation using the constant modulus algorithm (CMA) on the asynchronously sampled signal to initially separate energy from arbitrarily aligned polarization states. This method lends well to implementation as it allows for an open-loop sampling frequency for analog-to-digital conversion at less than twice the symbol rate. We show that the performance of subsequent receiver functions is enhanced by the initial pol demux operation. CMA singularity behavior is avoided through tap settling constraints. The method is applicable to QPSK transmissions and many other modulation formats as well, including general QAM signals, offset-QPSK, and CPM, or a combination thereof. We present the architecture and its performance under several different formats and link conditions. Comparisons of complexity and performance are drawn between the proposed architecture and conventional receivers.

  17. An Asynchronous IEEE Floating-Point Arithmetic Unit

    Directory of Open Access Journals (Sweden)

    Joel R. Noche

    2007-12-01

    Full Text Available An asynchronous floating-point arithmetic unit is designed and tested at the transistor level usingCadence software. It uses CMOS (complementary metal oxide semiconductor and DCVS (differentialcascode voltage switch logic in a 0.35 µm process using a 3.3 V supply voltage, with dual-rail data andsingle-rail control signals using four-phase handshaking.Using 17,085 transistors, the unit handles single-precision (32-bit addition/subtraction, multiplication,division, and remainder using the IEEE 754-1985 Standard for Binary Floating-Point Arithmetic, withrounding and other operations to be handled by separate hardware or software. Division and remainderare done using a restoring subtractive algorithm; multiplication uses an additive algorithm. Exceptionsare noted by flags (and not trap handlers and the output is in single-precision.Previous work on asynchronous floating-point arithmetic units have mostly focused on single operationssuch as division. This is the first work to the authors' knowledge that can perform floating-point addition,multiplication, division, and remainder using a common datapath.

  18. Fast asynchronous updating algorithms for k-shell indices

    Science.gov (United States)

    Lee, Yan-Li; Zhou, Tao

    2017-09-01

    Identifying influential nodes in networks is a significant and challenging task. Among many centrality indices, the k-shell index performs very well in finding out influential spreaders. However, the traditional method for calculating the k-shell indices of nodes needs the global topological information, which limits its applications in large-scale dynamically growing networks. Recently, Lü et al. [Nature Commun. 7 (2016) 10168] proposed a novel asynchronous algorithm to calculate the k-shell indices, which is suitable to deal with large-scale growing networks. In this paper, we propose two algorithms to select nodes and update their intermediate values towards the k-shell indices, which can help in accelerating the convergence of the calculation of k-shell indices. The former algorithm takes into account the degrees of nodes while the latter algorithm prefers to choose the node whose neighbors' values have been changed recently. We test these two methods on four real networks and four artificial networks. The results suggest that the two algorithms can respectively reduce the convergence time up to 75.4% and 92.9% in average, compared with the original asynchronous updating algorithm.

  19. Formation of the wide asynchronous binary asteroid population

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Seth A. [Department of Astrophysical and Planetary Science, UCB 391, University of Colorado, Boulder, CO 80309 (United States); Scheeres, Daniel J.; McMahon, Jay [Department of Aerospace Engineering Sciences, UCB 429, University of Colorado, Boulder, CO 80309 (United States)

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  20. Designing Parallel Bus Using Universal Asynchronous Receiver Transmitter

    Directory of Open Access Journals (Sweden)

    Satyandra Sharad

    2013-04-01

    Full Text Available This paper entitled “DESIGNING PARALLEL BUSUSING UNIVERSAL ASYNCHRONOUS RECEIVER TRANSMITTER” is designed to the core of a UART interface module, which includes both receive and transmit modules, and the command parser. This paper will be a viable solution to design parallel buses with the help of UART. In the test bench , there is a RFM(register file model to which we write/read back data from just to check our design .The txt file issues serial inputs to the core and the core outputs parallel data and address in the form of bus. This bus is connected to our RFM (register file model instantiated in the test bench along with the design. This makes easy to retrieve parallel data from serial input. The base of the paper is to use microcontroller along with other components to interface with the physical world. In contrast, most serial communication must first be converted back into parallel form by a universal asynchronous receiver/transmitter (UART before they may be directly connected to a data bus. Both Transmissions (Parallel and Serial are used to connect peripheral devices and enable us to communicate with these devices. The UART core described here is designed using VHDL and implemented on Xilinx Vertex FPGA.

  1. Asynchronous Code-Division Random Access Using Convex Optimization

    CERN Document Server

    Applebaum, Lorne; Duarte, Marco F; Calderbank, Robert

    2011-01-01

    Many applications in cellular systems and sensor networks involve a random subset of a large number of users asynchronously reporting activity to a base station. This paper examines the problem of multiuser detection (MUD) in random access channels for such applications. Traditional orthogonal signaling ignores the random nature of user activity in this problem and limits the total number of users to be on the order of the number of signal space dimensions. Contention-based schemes, on the other hand, suffer from delays caused by colliding transmissions and the hidden node problem. In contrast, this paper presents a novel asynchronous (non-orthogonal) code-division random access scheme along with a convex optimization-based MUD algorithm that overcomes the issues associated with orthogonal signaling and contention-based methods. Two key distinguishing features of the proposed algorithm are that it does not require knowledge of the delay or channel state information of every user and it has polynomial-time com...

  2. Asynchronous glaciation at Nanga Parbat, northwestern Himalaya Mountains, Pakistan

    Science.gov (United States)

    Phillips, William M.; Sloan, Valerie F.; Shroder, John F., Jr.; Sharma, Pankaj; Clarke, Michèle L.; Rendell, Helen M.

    2000-05-01

    We present a new glacial chronology demonstrating asynchroneity between advances of Himalayan glaciers and Northern Hemisphere ice-sheet volumes. Glaciers at Nanga Parbat expanded during the early to middle Holocene ca. 9.0 5.5 ka. No major advances at Nanga Parbat during the last global glacial stage of marine oxygen isotope stage 2 (MIS-2) between 24 and 11 ka were identified. Preliminary evidence also indicates advances between ca. 60 and 30 ka. These periods of high ice volume coincide with warm, wet regional climates dominated by a strong southwest Asian summer monsoon. The general lack of deposits dating from MIS-2 suggests that Nanga Parbat was too arid to support expanded ice during this period of low monsoon intensity. Advances during warm, wet periods are possible for the high-altitude summer accumulation glaciers typical of the Himalayas, and explain asynchronous behavior. However, the Holocene advances at Nanga Parbat appear to have been forced by an abrupt drop in temperature ca. 8.4 8.0 ka and an increase in winter precipitation ca. 7 5.5 ka. These results highlight the overall sensitivity of Himalayan glaciation to orbital forcing of monsoon intensity, and on millennial or shorter time scales, to changes in North Atlantic circulation.

  3. Spatiotemporal Features for Asynchronous Event-based Data

    Directory of Open Access Journals (Sweden)

    Xavier eLagorce

    2015-02-01

    Full Text Available Bio-inspired asynchronous event-based vision sensors are currently introducing a paradigm shift in visual information processing. These new sensors rely on a stimulus-driven principle of light acquisition similar to biological retinas. They are event-driven and fully asynchronous, thereby reducing redundancy and encoding exact times of input signal changes, leading to a very precise temporal resolution. Approaches for higher-level computer vision often rely on the realiable detection of features in visual frames, but similar definitions of features for the novel dynamic and event-based visual input representation of silicon retinas have so far been lacking. This article addresses the problem of learning and recognizing features for event-based vision sensors, which capture properties of truly spatiotemporal volumes of sparse visual event information. A novel computational architecture for learning and encoding spatiotemporal features is introduced based on a set of predictive recurrent reservoir networks, competing via winner-take-all selection. Features are learned in an unsupervised manner from real-world input recorded with event-based vision sensors. It is shown that the networks in the architecture learn distinct and task-specific dynamic visual features, and can predict their trajectories over time.

  4. Asynchronous Task-Based Polar Decomposition on Manycore Architectures

    KAUST Repository

    Sukkari, Dalal

    2016-10-25

    This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

  5. Simplified and advanced modelling of traction control systems of heavy-haul locomotives

    Science.gov (United States)

    Spiryagin, Maksym; Wolfs, Peter; Szanto, Frank; Cole, Colin

    2015-05-01

    Improving tractive effort is a very complex task in locomotive design. It requires the development of not only mechanical systems but also power systems, traction machines and traction algorithms. At the initial design stage, traction algorithms can be verified by means of a simulation approach. A simple single wheelset simulation approach is not sufficient because all locomotive dynamics are not fully taken into consideration. Given that many traction control strategies exist, the best solution is to use more advanced approaches for such studies. This paper describes the modelling of a locomotive with a bogie traction control strategy based on a co-simulation approach in order to deliver more accurate results. The simplified and advanced modelling approaches of a locomotive electric power system are compared in this paper in order to answer a fundamental question. What level of modelling complexity is necessary for the investigation of the dynamic behaviours of a heavy-haul locomotive running under traction? The simulation results obtained provide some recommendations on simulation processes and the further implementation of advanced and simplified modelling approaches.

  6. Size and composition of airborne particles from pavement wear, tires, and traction sanding.

    Science.gov (United States)

    Kupiainen, Kaarle J; Tervahattu, Heikki; Räisänen, Mika; Mäkelä, Timo; Aurela, Minna; Hillamo, Risto

    2005-02-01

    Mineral matter is an important component of airborne particles in urban areas. In northern cities of the world, mineral matter dominates PM10 during spring because of enhanced road abrasion caused by the use of antiskid methods, including studded tires and traction sanding. In this study, factors that affect formation of abrasion components of springtime road dust were assessed. Effects of traction sanding and tires on concentrations, mass size distribution, and composition of the particles were studied in a test facility. Lowest particle concentrations were observed in tests without traction sanding. The concentrations increased when traction sand was introduced and continued to increase as a function of the amount of aggregate dispersed. Emissions were additionally affected by type of tire, properties of traction sand aggregate, and driving speed. Aggregates with high fragmentation resistance and coarse grain size distribution had the lowest emissions. Over 90% of PM10 was mineral particles. Mineralogy of the dust and source apportionment showed that they originated from both traction sand and pavement aggregates. The remaining portion was mostly carbonaceous and originated from tires and road bitumen. Mass size distributions were dominated by coarse particles. Contribution of fine and submicron size ranges were approximately 15 and 10% in PM10, respectively.

  7. Myosin IIA deficient cells migrate efficiently despite reduced traction forces at cell periphery

    Directory of Open Access Journals (Sweden)

    Melissa H. Jorrisch

    2013-02-01

    Cell motility is a cornerstone of embryogenesis, tissue remodeling and repair, and cancer cell invasion. It is generally thought that migrating cells grab and exert traction force onto the extracellular matrix in order to pull the cell body forward. While previous studies have shown that myosin II deficient cells migrate efficiently, whether these cells exert traction forces during cell migration in the absence of the major contractile machinery is currently unknown. Using an array of micron-sized pillars as a force sensor and shRNA specific to each myosin II isoform (A and B, we analyzed how myosin IIA and IIB individually regulate cell migration and traction force generation. Myosin IIA and IIB localized preferentially to the leading edge where traction force was greatest, and the trailing edge, respectively. When individual myosin II isoforms were depleted by shRNA, myosin IIA deficient cells lost actin stress fibers and focal adhesions, whereas myosin IIB deficient cells maintained similar actin organization and focal adhesions as wild-type cells. Interestingly, myosin IIA deficient cells migrated faster than wild-type or myosin IIB deficient cells on both a rigid surface and a pillar array, yet myosin IIA deficient cells exerted significantly less traction force at the leading edge than wild-type or myosin IIB deficient cells. These results suggest that, in the absence of myosin IIA mediated force-generating machinery, cells move with minimal traction forces at the cell periphery, thus demonstrating the remarkable ability of cells to adapt and migrate.

  8. Both contractile axial and lateral traction force dynamics drive amoeboid cell motility.

    Science.gov (United States)

    Bastounis, Effie; Meili, Ruedi; Álvarez-González, Begoña; Francois, Joshua; del Álamo, Juan C; Firtel, Richard A; Lasheras, Juan C

    2014-03-17

    Chemotaxing Dictyostelium discoideum cells adapt their morphology and migration speed in response to intrinsic and extrinsic cues. Using Fourier traction force microscopy, we measured the spatiotemporal evolution of shape and traction stresses and constructed traction tension kymographs to analyze cell motility as a function of the dynamics of the cell's mechanically active traction adhesions. We show that wild-type cells migrate in a step-wise fashion, mainly forming stationary traction adhesions along their anterior-posterior axes and exerting strong contractile axial forces. We demonstrate that lateral forces are also important for motility, especially for migration on highly adhesive substrates. Analysis of two mutant strains lacking distinct actin cross-linkers (mhcA(-) and abp120(-) cells) on normal and highly adhesive substrates supports a key role for lateral contractions in amoeboid cell motility, whereas the differences in their traction adhesion dynamics suggest that these two strains use distinct mechanisms to achieve migration. Finally, we provide evidence that the above patterns of migration may be conserved in mammalian amoeboid cells.

  9. Topographical control of multiple cell adhesion molecules for traction force microscopy.

    Science.gov (United States)

    Polio, Samuel R; Parameswaran, Harikrishnan; Canović, Elizabeth P; Gaut, Carolynn M; Aksyonova, Diana; Stamenović, Dimitrije; Smith, Michael L

    2014-03-01

    Cellular traction forces are important quantitative measures in cell biology as they have provided much insight into cell behavior in contexts such as cellular migration, differentiation, and disease progression. However, the complex environment in vivo permits application of cell traction forces through multiple types of cell adhesion molecules. Currently available approaches to differentiate traction forces among multiple cell adhesion molecules are limited to specialized approaches to decouple cell-cell from cell-extracellular matrix (ECM) tractions. Here, we present a technique which uses indirect micropatterning onto a polyacrylamide gel to pattern multiple, spatially distinct fluorescently labeled ECM proteins, specifically gelatin and fibronectin (Fn), and confine the area to which cells can adhere. We found that cells interacting with both gelatin and Fn altered their traction forces significantly in comparison to cells on Fn-only substrates. This crosstalk interaction resulted in a decrease in overall traction forces on dual-patterned substrates as compared to cells on Fn-only substrates. This illustrates the unique need to study such interactions and demonstrates great potential in future studies in multi-ligand environments. Current micropatterning techniques on glass can easily be adapted to present other protein classes, such as cadherins, while maintaining control of adhesion spacing, cell spread area, and stiffness, each of which are important regulators of cell mechanobiology.

  10. Spatial and temporal coordination of traction forces in one-dimensional cell migration.

    Science.gov (United States)

    Han, Sangyoon J; Rodriguez, Marita L; Al-Rekabi, Zeinab; Sniadecki, Nathan J

    2016-09-02

    Migration of a fibroblast along a collagen fiber can be regarded as cell locomotion in one-dimension (1D). In this process, a cell protrudes forward, forms a new adhesion, produces traction forces, and releases its rear adhesion in order to advance itself along a path. However, how a cell coordinates its adhesion formation, traction forces, and rear release in 1D migration is unclear. Here, we studied fibroblasts migrating along a line of microposts. We found that when the front of a cell protruded onto a new micropost, the traction force produced at its front increased steadily, but did so without a temporal correlation in the force at its rear. Instead, the force at the front coordinated with a decrease in force at the micropost behind the front. A similar correlation in traction forces also occurred at the rear of a cell, where a decrease in force due to adhesion detachment corresponded to an increase in force at the micropost ahead of the rear. Analysis with a bio-chemo-mechanical model for traction forces and adhesion dynamics indicated that the observed relationship between traction forces at the front and back of a cell is possible only when cellular elasticity is lower than the elasticity of the cellular environment.

  11. Myosin IIA deficient cells migrate efficiently despite reduced traction forces at cell periphery.

    Science.gov (United States)

    Jorrisch, Melissa H; Shih, Wenting; Yamada, Soichiro

    2013-04-15

    Cell motility is a cornerstone of embryogenesis, tissue remodeling and repair, and cancer cell invasion. It is generally thought that migrating cells grab and exert traction force onto the extracellular matrix in order to pull the cell body forward. While previous studies have shown that myosin II deficient cells migrate efficiently, whether these cells exert traction forces during cell migration in the absence of the major contractile machinery is currently unknown. Using an array of micron-sized pillars as a force sensor and shRNA specific to each myosin II isoform (A and B), we analyzed how myosin IIA and IIB individually regulate cell migration and traction force generation. Myosin IIA and IIB localized preferentially to the leading edge where traction force was greatest, and the trailing edge, respectively. When individual myosin II isoforms were depleted by shRNA, myosin IIA deficient cells lost actin stress fibers and focal adhesions, whereas myosin IIB deficient cells maintained similar actin organization and focal adhesions as wild-type cells. Interestingly, myosin IIA deficient cells migrated faster than wild-type or myosin IIB deficient cells on both a rigid surface and a pillar array, yet myosin IIA deficient cells exerted significantly less traction force at the leading edge than wild-type or myosin IIB deficient cells. These results suggest that, in the absence of myosin IIA mediated force-generating machinery, cells move with minimal traction forces at the cell periphery, thus demonstrating the remarkable ability of cells to adapt and migrate.

  12. Acetabular labral tears: contrast-enhanced MR imaging under continuous leg traction

    Energy Technology Data Exchange (ETDEWEB)

    Nishii, T. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Nakanishi, K. [Dept. of Radiology, Osaka Univ. Medical School, Suita (Japan); Sugano, N. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan); Naito, H. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Tamura, S. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Ochi, T. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan)

    1996-05-01

    The objective of this study was to evaluate the effects of continuous leg traction on contrast-enhanced MR imaging of the hip joint and to determine whether MR imaging under these conditions is useful for demonstrating acetabular labral tears. Nineteen hips underwent MR imaging with a T1-weighted spin-echo sequence, followed by MR imaging under continuous leg traction after intravenous injection of gadolinium-DTPA. Joint fluid enhancement and labral contour detection were evaluated. Eleven hips had labral tears shown by conventional arthrography, arthroscopy and macroscopic surgical findings. Assessment of labral tears by MR imaging was correlated with the diagnosis based on these standard techniques. Joint fluid enhancement was obtained in all hips at 30 min after injection. Superior and inferior labral surfaces were completely delineated in 1 hip on the unenhanced MR images, and in 7 and 13 hips, respectively, on the enhanced images under traction. The enhanced images under traction depicted 9 of the 11 labral tears. Comparison between the unenhanced image and the enhanced image under traction avoided mistaking undercutting of the labrum for a tear in 4 hips. Contrast-enhanced MR imaging under traction was valuable for detecting labral tears non-invasively and without radiation. Follow-up examinations using this method in patients with acetabular dysplasia can help to clarify the natural course of labral disorders and enable better treatment planning. (orig./MG)

  13. Coulomb traction on a penny-shaped crack in a three dimensional piezoelectric body

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qun; Kuna, Meinhard [TU Bergakademie Freiberg, Institute of Mechanics and Fluid Dynamics, Freiberg (Germany); Ricoeur, Andreas [University of Kassel, Institute of Mechanics, Kassel (Germany)

    2011-06-15

    The axisymmetric problem of a penny-shaped crack embedded in an infinite three-dimensional (3D) piezoelectric body is considered. A general formulation of Coulomb traction on the crack surfaces can be obtained based on thermodynamical considerations of electromechanical systems. Three-dimensional electroelastic solutions are derived by the classical complex potential theory when Coulomb traction is taken into account and the poling direction of piezoelectric body is perpendicular to the crack surfaces. Numerical results show that the magnitude of Coulomb tractions can be large, especially when a large electric field in connection with a small mechanical load is applied. Unlike the traditional traction-free crack model, Coulomb tractions induced by an applied electric field influence the Mode I stress intensity factor for a penny-shaped crack in 3D piezoelectric body. Moreover, compared to the current model, the traditional traction-free crack model always overestimates the effect of the applied electric load on the field intensity factors and energy release rates, which has consequences for 3D piezoelectric fracture mechanics. (orig.)

  14. Influence of basketball shoe mass, outsole traction, and forefoot bending stiffness on three athletic movements.

    Science.gov (United States)

    Worobets, Jay; Wannop, John William

    2015-09-01

    Prior research has shown that footwear can enhance athletic performance. However, public information is not available on what basketball shoe properties should be selected to maximise movement performance. Therefore, the purpose of the study was to investigate the influence of basketball shoe mass, outsole traction, and forefoot bending stiffness on sprinting, jumping, and cutting performance. Each of these three basketball shoe properties was systematically varied by ± 20% to produce three shoe conditions of varying mass, three conditions of varying traction, and three conditions of varying bending stiffness. Each shoe was tested by 20 recreational basketball players completing maximal effort sprints, vertical jumps, and a cutting drill. Outsole traction had the largest influence on performance, as the participants performed significantly worse in all tests when traction was decreased by 20% (p < 0.001), and performed significantly better in the cutting drill when traction was increased by 20% (p = 0.005). Forefoot bending stiffness had a moderate effect on sprint and cutting performance (p = 0.013 and p = 0.016 respectively) and shoe mass was found to have no effect on performance. Therefore, choosing a shoe with relatively high outsole traction and forefoot bending stiffness should be prioritised, and less concern should be focused on selecting the lightest shoe.

  15. A Study of Torque Vectoring and Traction Control for an All-Wheel Drive Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Maharun Mui’nuddin

    2014-07-01

    Full Text Available Common vehicle always experience energy loss during cornering manoeuver. Thus, to ensure it did not happened especially at high speed, a study of torque vectoring and traction control need to be made since it can increase the traction control of tyres during cornering at high speed. The study of torque vectoring and traction control for an all-wheel drive electric vehicle was conducted by modelling an all-wheel drive electric vehicle (EV in ADAMS/Car software. In addition, an optimal control algorithm will be developed for best performance to minimize energy losses using MATLAB/Simulink software. Furthermore, to prove the effectiveness of the all-wheel drive electric, the torque and traction control simulation of the all-wheel drive electric vehicle will be compared with uncontrolled electric vehicle model. According to the result, torque vectoring and traction control of in-wheel motor in all wheel drive EV can help to increase the performance of the electric vehicle during cornering manoeuver. In conclusion, this study of torque vectoring and traction control for an all-wheel drive electric vehicle will help researchers to improve the design of the future electric vehicle in term of the vehicle performance during cornering manoeuvre.

  16. Super Low Traction under EHD and Mixed Lubrication Regimes

    CERN Document Server

    Vergne, Philippe

    2007-01-01

    After the pioneered experimental works on superlubricity by Martin et al. on MoS2 [1], Hirano et al. on tungsten and silicon [2] and the further confirmation by Dienwiebel et al. on graphite [3], many groups around the word investigated the occurrence of near frictionless sliding contacts. This large mobilization of tribologists, material sciences specialists and physicists has lead to emerging solutions involving new materials and coatings, the most promising being carbon based like graphite, diamond, carbon composites or diamond-like-carbons. Some of them are currently used in practical applications. The situation is different especially in EHL: the highest friction coefficients are close to 10% when traction fluids are involved, i.e. fluids that have especially designed to transmit the highest friction, and they vary within 3-6% for the rest of lubricants. The range of variation is consequently very narrow and these typical values are really low compared to those obtained in dry contacts: as a consequence ...

  17. [Mesenteric traction syndrome during coronary artery bypass graft surgery].

    Science.gov (United States)

    Koyama, K; Kaneko, I; Mori, K

    1997-02-01

    Mesenteric traction syndrome (MTS) consists of decreased systemic vascular resistance, increased cardiac output, facial flushing and palmar erythema. Local production of PGI2 is thought to be the cause. We experienced a rare case of MTS that occurred during coronary artery bypass graft surgery (CABG). A 64-year-old man was scheduled for CABG for the treatment of angina pectoris. Hemodynamic variables were stable until 50 minutes after surgical incision. Blood pressure fell down suddenly from 110/50 to 70/40 mmHg, accompanied by obvious facial flushing and palmar erythema, when the surgeons were preparing the right gastroepiploic artery. Hemodynamic changes and cutaneous hyperemia returned to the baseline level in about 40 minutes. After this episode, the operation was performed uneventfully. The time sequence between the onset of the surgical procedure and the hemodynamic and cutaneous findings strongly suggest the release of PGI2 and MTS. In patients undergoing CABG with the gastroepiploic artery graft, pretreatment with NSAID might avoid sudden circulatory changes of MTS.

  18. Two-Layer Elastographic 3-D Traction Force Microscopy

    Science.gov (United States)

    Álvarez-González, Begoña; Zhang, Shun; Gómez-González, Manuel; Meili, Ruedi; Firtel, Richard A.; Lasheras, Juan C.; Del Álamo, Juan C.

    2017-01-01

    Cellular traction force microscopy (TFM) requires knowledge of the mechanical properties of the substratum where the cells adhere to calculate cell-generated forces from measurements of substratum deformation. Polymer-based hydrogels are broadly used for TFM due to their linearly elastic behavior in the range of measured deformations. However, the calculated stresses, particularly their spatial patterns, can be highly sensitive to the substratum’s Poisson’s ratio. We present two-layer elastographic TFM (2LETFM), a method that allows for simultaneously measuring the Poisson’s ratio of the substratum while also determining the cell-generated forces. The new method exploits the analytical solution of the elastostatic equation and deformation measurements from two layers of the substratum. We perform an in silico analysis of 2LETFM concluding that this technique is robust with respect to TFM experimental parameters, and remains accurate even for noisy measurement data. We also provide experimental proof of principle of 2LETFM by simultaneously measuring the stresses exerted by migrating Physarum amoeboae on the surface of polyacrylamide substrata, and the Poisson’s ratio of the substrata. The 2LETFM method could be generalized to concurrently determine the mechanical properties and cell-generated forces in more physiologically relevant extracellular environments, opening new possibilities to study cell-matrix interactions.

  19. Whiplash-associated chronic headache treated with home cervical traction.

    Science.gov (United States)

    Olson, V L

    1997-04-01

    The subject of this case report was a 56-year-old woman who sustained a whiplash-associated disorder as a result of a motor vehicle accident. Within a few hours after the accident, she developed a headache, which became chronic, creating disability and hindering the quality of her life. In the following year, a variety of diagnostic tests, medications, and physical therapy were unsuccessful in determining the cause of her complaints or in relieving them. After this year, she expressed anger, frustration, and a reluctance to undergo additional physical therapy. By listening to her explain how she coped with her problem and observing that she lacked the ability to reduce her cervical lordosis, the therapist developed and implemented a home program of supine cervical traction and exercise. After 30 days of treatment, she was able to reduce and control her headache. This treatment and the approach used to develop the treatment may benefit other patients who have whiplash-associated chronic headache.

  20. Asynchronous API Pattern and its Application%异步接口模式及其应用

    Institute of Scientific and Technical Information of China (English)

    何华海; 丁柯

    2002-01-01

    In distributed systems,high efficiency can be achieved using asynchronous API between client and server.This paper provides an architectural pattern that implements asynchronous API generally. Asynchronous methods donot execute operations directly,however,they delegate the sending and receiving process to individual threads via aqueue ,the client deals with results by means of callback ,wait or check. Synchronous API is implemented on the baseof asynchronous API. Presently the asynchronous API pattern has been employed in the implementation of messagequeue middleware ISMQ.

  1. Effect of intermittent, supine cervical traction on the myoelectric activity of the upper trapezius muscle in subjects with neck pain.

    Science.gov (United States)

    Jette, D U; Falkel, J E; Trombly, C

    1985-08-01

    This study was undertaken to compare the myoelectric activity of the upper trapezius muscle before, during, and after intermittent, supine cervical traction. Twelve people with diagnosed disease or injury of the cervical spine served as subjects. Electromyographic recordings were taken from the upper trapezius muscle with bipolar surface electrodes. The subjects were treated with 20 minutes of intermittent, cervical traction at a force of 8% of their body weight. Recordings were taken with the subjects in the supine position before the traction, during one pull and release phase of the 10th and 20th minutes of traction, and after completion of the traction treatment. An analysis of variance with repeated measures showed no significant differences in the myoelectrical activity during the six time periods measured. The results of this study do not support the clinical use of intermittent, supine traction to produce cervical muscle relaxation.

  2. Electrical Energy Quality Studies in 3 kV DC Electric Traction Systems for Different Schemes of Connection Traction Substation to Power Utility System

    Directory of Open Access Journals (Sweden)

    Pavel Jankowski

    2004-01-01

    Full Text Available The paper present aspects of DC electric traction system influence on electric energetic system. Study is based on modeling and simulation of electrified railway line. After simulation, there was performed analysis of energy quality, whitch using results of simulation and supply systems parameters.

  3. 组织工程化小肠黏膜下层生物膜用于牙种植牵引的实验研究%Experimental study of tissue-engineered biological small intestinal submucosa,membrane employed in dental implant traction

    Institute of Scientific and Technical Information of China (English)

    李华; 韩正学; 徐立群; 张陈平

    2009-01-01

    Objective To construct the tissue-engineered biological small intestinal submucosa(SIS)membrane and evaluate the feasibility of its use as a surrogate of periosteum and its possible role in dental implant distraction(DID).Methods The tissue-engineered biological SIS inembrane was,constructed through the co-culturing of boat bone marrow stromal cells(BMSC)and small intestinal submucosa.The celluar compatibility was evaluated with the phase contrast microscope,SEM,alkaline phosphatase(ALP)activity and histology,and its effect of ostcogenesis promotion was detected by Micro-CTand histology after implanted in the export side of DID operation.Results The phase contrast microscope,SEM,ALP activity and histology confirmed that the BMSC could adhere to SIS and proliferate on it normally,the cellular activity and function were not affected by SIS.Three months after the tissue-engineered biological SIS membrane was implanted into the exposed side,sonle discontinuous new bone in the"biological SIS membrane"group was detected by the Micro-CT under a higher window level.The histology revealed that there was a quantity of new bone in the distracted region and the majority was woven bone.The quantity and quality ofthe new bone in the"biological SIS membrane"implanted group were similar to the unexposed side,but the bone nonunion was detected in the un-implanted group and the interspace was fixed by fibrous connective tissue.Conclusions The tissueengineered biological SIS membrane can provid both daughter cells,guide bone regeneration in DID and promote the osteogenesis.But the outcome of the biological SIS membrane,especially the function of the osteoblast culmred in the SIS in new bone formation,still needs further study.%目的 构建组织工程化小肠黏膜下层(small intestinal submucosa,SIS)生物膜,评价其作为骨膜替代物的可行性及其在牙种植牵引(dental implant distraction,DID)中的作用.方法 取10只山羊设自身对照,

  4. Large-scale asynchronous and distributed multidimensional replica exchange molecular simulations and efficiency analysis.

    Science.gov (United States)

    Xia, Junchao; Flynn, William F; Gallicchio, Emilio; Zhang, Bin W; He, Peng; Tan, Zhiqiang; Levy, Ronald M

    2015-09-05

    We describe methods to perform replica exchange molecular dynamics (REMD) simulations asynchronously (ASyncRE). The methods are designed to facilitate large scale REMD simulations on grid computing networks consisting of heterogeneous and distributed computing environments as well as on homogeneous high-performance clusters. We have implemented these methods on NSF (National Science Foundation) XSEDE (Extreme Science and Engineering Discovery Environment) clusters and BOINC (Berkeley Open Infrastructure for Network Computing) distributed computing networks at Temple University and Brooklyn College at CUNY (the City University of New York). They are also being implemented on the IBM World Community Grid. To illustrate the methods, we have performed extensive (more than 60 ms in aggregate) simulations for the beta-cyclodextrin-heptanoate host-guest system in the context of one- and two-dimensional ASyncRE, and we used the results to estimate absolute binding free energies using the binding energy distribution analysis method. We propose ways to improve the efficiency of REMD simulations: these include increasing the number of exchanges attempted after a specified molecular dynamics (MD) period up to the fast exchange limit and/or adjusting the MD period to allow sufficient internal relaxation within each thermodynamic state. Although ASyncRE simulations generally require long MD periods (>picoseconds) per replica exchange cycle to minimize the overhead imposed by heterogeneous computing networks, we found that it is possible to reach an efficiency similar to conventional synchronous REMD, by optimizing the combination of the MD period and the number of exchanges attempted per cycle.

  5. Robust Fault-Tolerant Tracking Control for Nonlinear Networked Control System: Asynchronous Switched Polytopic Approach

    Directory of Open Access Journals (Sweden)

    Chaoyang Dong

    2015-01-01

    Full Text Available This paper is concerned with the robust fault-tolerant tracking control problem for networked control system (NCS. Firstly, considering the locally overlapped switching law widely existed in engineering applications, the NCS is modeled as a locally overlapped switched polytopic system to reduce designing conservatism and solving complexity. Then, switched parameter dependent fault-tolerant tracking controllers are constructed to deal with the asynchronous switching phenomenon caused by the updating delays of the switching signals and weighted coefficients. Additionally, the global uniform asymptotic stability in the mean (GUAS-M and desired weighted l2 performance are guaranteed by combining the switched parameter dependent Lyapunov functional method with the average dwell time (ADT method, and the feasible conditions for the fault-tolerant tracking controllers are obtained in the form of linear matrix inequalities (LMIs. Finally, the performance of the proposed approach is verified on a highly maneuverable technology (HiMAT vehicle’s tracking control problem. Simulation results show the effectiveness of the proposed method.

  6. An Asynchronous Many-Task Implementation of In-Situ Statistical Analysis using Legion.

    Energy Technology Data Exchange (ETDEWEB)

    Pebay, Philippe Pierre [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bennett, Janine Camille [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-11-01

    In this report, we propose a framework for the design and implementation of in-situ analy- ses using an asynchronous many-task (AMT) model, using the Legion programming model together with the MiniAero mini-application as a surrogate for full-scale parallel scientific computing applications. The bulk of this work consists of converting the Learn/Derive/Assess model which we had initially developed for parallel statistical analysis using MPI [PTBM11], from a SPMD to an AMT model. In this goal, we propose an original use of the concept of Legion logical regions as a replacement for the parallel communication schemes used for the only operation of the statistics engines that require explicit communication. We then evaluate this proposed scheme in a shared memory environment, using the Legion port of MiniAero as a proxy for a full-scale scientific application, as a means to provide input data sets of variable size for the in-situ statistical analyses in an AMT context. We demonstrate in particular that the approach has merit, and warrants further investigation, in collaboration with ongoing efforts to improve the overall parallel performance of the Legion system.

  7. Time-dependent traction force microscopy for cancer cells as a measure of invasiveness.

    Science.gov (United States)

    Peschetola, Valentina; Laurent, Valérie M; Duperray, Alain; Michel, Richard; Ambrosi, Davide; Preziosi, Luigi; Verdier, Claude

    2013-04-01

    The migration of tumor cells of different degrees of invasivity is studied, on the basis of the traction forces exerted in time on soft substrates (Young modulus∼10 kPa). It is found that the outliers of the traction stresses can be an effective indicator to distinguish cancer cell lines of different invasiveness. Here, we test two different epithelial bladder cancer cell lines, one invasive (T24), and a less invasive one (RT112). Invasive cancer cells move in a nearly periodic motion, with peaks in velocity corresponding to higher traction forces exerted on the substrate, whereas less invasive cells develop traction stresses almost constant in time. The dynamics of focal adhesions (FAs) as well as cytoskeleton features reveals that different mechanisms are activated to migrate: T24 cells show an interconnected cytoskeleton linked to mature adhesion sites, leading to small traction stresses, whereas less invasive cells (RT112) show a less-structured cytoskeleton and unmature adhesions corresponding to higher traction stresses. Migration velocities are smaller in the case of less invasive cells. The mean squared displacement shows super-diffusive motion in both cases with higher exponent for the more invasive cancer cells. Further correlations between traction forces and the actin cytoskeleton reveal an unexpected pattern of a large actin rim at the RT112 cell edge where higher forces are colocalized, whereas a more usual cytoskeleton structure with stress fibers and FAs are found for T24 cancer cells. We conjecture that this kind of analysis can be useful to classify cancer cell invasiveness. Copyright © 2013 Wiley Periodicals, Inc.

  8. New Approach to the Power Selection for Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    高建华; 胡洪国; 杨汝清

    2001-01-01

    The heating calculation of three-phase squirrel- cage asynchronous motor on the condition of starting for a prescribed rotary angle is firstly studied with time dissection method and its corresponding algorithm is provided. Then based upon the algorithm, a new method for motor power selection is established. Motor initial power determined by load power ischecked and modified in terms of time crit erion, heating criterion,and starting torque criterion.An appropriate motor power which meets three criterions is obtained at last, in the meantime, working displacement matrix andfrequency matrix used for control are acquired. Lifting motor of MDJ1800 low-level high- speed palletizer is taken as a reaI case in the paper.

  9. Vector control structure of an asynchronous motor at maximum torque

    Science.gov (United States)

    Chioncel, C. P.; Tirian, G. O.; Gillich, N.; Raduca, E.

    2016-02-01

    Vector control methods offer the possibility to gain high performance, being widely used. Certain applications require an optimum control in limit operating conditions, as, at maximum torque, that is not always satisfied. The paper presents how the voltage and the frequency for an asynchronous machine (ASM) operating at variable speed are determinate, with an accent on the method that keeps the rotor flux constant. The simulation analyses consider three load types: variable torque and speed, variable torque and constant speed, constant torque and variable speed. The final values of frequency and voltage are obtained through the proposed control schemes with one controller using the simulation language based on the Maple module. The dynamic analysis of the system is done for the case with P and PI controller and allows conclusions on the proposed method, which can have different applications, as the ASM in wind turbines.

  10. Estimation of delays in generalized asynchronous Boolean networks.

    Science.gov (United States)

    Das, Haimabati; Layek, Ritwik Kumar

    2016-10-20

    A new generalized asynchronous Boolean network (GABN) model has been proposed in this paper. This continuous-time discrete-state model captures the biological reality of cellular dynamics without compromising the computational efficiency of the Boolean framework. The GABN synthesis procedure is based on the prior knowledge of the logical structure of the regulatory network, and the experimental transcriptional parameters. The novelty of the proposed methodology lies in considering different delays associated with the activation and deactivation of a particular protein (especially the transcription factors). A few illustrative examples of some well-studied network motifs have been provided to explore the scope of using the GABN model for larger networks. The GABN model of the p53-signaling pathway in response to γ-irradiation has also been simulated in the current paper to provide an indirect validation of the proposed schema.

  11. Label-acquired magnetorotation for biosensing: An asynchronous rotation assay

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Ariel, E-mail: hecht@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); Kinnunen, Paivo, E-mail: pkkinn@umich.ed [University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); McNaughton, Brandon, E-mail: bmcnaugh@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); Kopelman, Raoul, E-mail: kopelman@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States)

    2011-02-15

    This paper presents a novel application of magnetic particles for biosensing, called label-acquired magnetorotation (LAM). This method is based on a combination of the traditional sandwich assay format with the asynchronous magnetic bead rotation (AMBR) method. In label-acquired magnetorotation, an analyte facilitates the binding of a magnetic label bead to a nonmagnetic solid phase sphere, forming a sandwich complex. The sandwich complex is then placed in a rotating magnetic field, where the rotational frequency of the sandwich complex is a function of the amount of analyte attached to the surface of the sphere. Here, we use streptavidin-coated beads and biotin-coated particles as analyte mimics, to be replaced by proteins and other biological targets in future work. We show this sensing method to have a dynamic range of two orders of magnitude.

  12. Research on DSP-based Asynchronous Motor Control Technology

    Directory of Open Access Journals (Sweden)

    Jun Yao

    2013-05-01

    Full Text Available The Motor in a variety of electrical transmission and position servo system occupies an extremely important position. After the DSP technology being applied to the motor control, the unification of the hardware and the flexibility of the software can be combined. Take the brushless DC motor for example, studied the mathematical model and the structure of the motor control system, also obtained the design scheme of the DSP-based asynchronous motor control system. With TI's 32 bit fixed point DSPTMS320F2812 as the core design of the hardware system, we wrote the system software, debug the motor control system and the results show that the system achieves the expected effect. The results of the research can be applied to brushless DC motor and other motor control, it will have a wide application prospects.

  13. Security technologies and protocols for Asynchronous Transfer Mode networks

    Energy Technology Data Exchange (ETDEWEB)

    Tarman, T.D.

    1996-06-01

    Asynchronous Transfer Mode (ATM) is a new data communications technology that promises to integrate voice, video, and data traffic into a common network infrastructure. In order to fully utilize ATM`s ability to transfer real-time data at high rates, applications will start to access the ATM layer directly. As a result of this trend, security mechanisms at the ATM layer will be required. A number of research programs are currently in progress which seek to better understand the unique issues associated with ATM security. This paper describes some of these issues, and the approaches taken by various organizations in the design of ATM layer security mechanisms. Efforts within the ATM Forum to address the user communities need for ATM security are also described.

  14. Profiling individual discussants’ behaviours in online asynchronous discussions

    Directory of Open Access Journals (Sweden)

    Elizabeth Murphy

    2006-06-01

    Full Text Available This paper provides an illustrative example of an approach to creating and reporting individual profiles of engagement in particular behaviours in an online asynchronous discussion (OAD. Individual results of analysis of transcripts of an OAD can provide insights different from those gained by focusing on aggregate measures of group behaviours. In this case, we focused on individual behaviours associated with Problem Formulation and Resolution (PFR in a one-month long OAD with seven graduate students. The transcripts of each participant were analysed for patterns of PFR behaviours using a previously designed instrument. Individual profiles of the seven participants were created. The paper provides examples of how the approach facilitated identification and comparison of individual weaknesses and strengths. Also provided are examples of how individual profiles might be useful in professional development and instructional contexts for formative or summative assessment purposes.

  15. Numerical Simulation of Asynchronous Simulated Moving Bed Chromatography

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    Asynchronous simulated moving bed chromatography (ASMBC), known also as the "VARICOL" process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.

  16. Research on the displacement control method of asynchronous modular contactor

    Science.gov (United States)

    He, Gong; Ming, Zong

    2017-01-01

    Ac contactor is a kind of low voltage electrical appliances with large usage and wide application. Because of the frequent operation, contactor life must be long enough to ensure the reliable operation of power system. The electrical life of the contactor, as the key to affect the service life of the contactor, is mainly affected by the arc developed in the breaking and closing course. This paper concentrates on a new type of asynchronous modular contactor. To get the contactor movement characteristics, the dynamic model of the electromagnetic system is established by MATLAB/SIMULINK. Then, according to the displacement curve of contactor, the breaking process and closing process is planned. The thought of closed loop control, by adjusting the parameters of PID controller, enables the contactor to operate as the planning displacement curve. In addition, to achieve no arc or micro arc breaking and no bounce or micro bounce closing , a displacement closed loop control system for contactor is designed.

  17. Asynchronous Multilateral Control for Simplified Walking Haptic System

    Science.gov (United States)

    Okura, Takeshi; Katsura, Seiichiro

    Recently, there has been extensive development in remote communication technologies such as telephone, radio, and television. Haptic information is studied as the third type of multimedia information. Real-world haptics is getting attention not only for the feedback of real-world haptic information in teleoperation but also as the key technology for future human support. Most of the objects of study in haptics are stationary. Therefore, the moving range of such haptic systems is limited. This paper proposes a novel haptic device that receives force feedback of walking motion from a remote environment and manipulates remote system. Thus, its moving range is unrestricted. To drive this haptic system, the paper also proposes asynchronous multilateral control. By using this control, an operator can operate the remote system without changing his/her position. The proposed haptic system is expected to act as an effective interface for virtual reality applications and teleoperation.

  18. H∞ Controller Design for Asynchronous Hybrid Systems with Multiple Delays

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Sun

    2016-01-01

    Full Text Available Solutions for the H∞ synthesis problems of asynchronous hybrid systems with input-output delays are proposed. The continuous-time lifting approach of sampled-data systems is extended to a hybrid system with multiple delays, and some feasible formulas to calculate the operators of the equivalent discrete-time (DT system are given. Different from the existing methods derived from symplectic pair theory or by state augmentation, a Lyapunov-Krasovskii functional to solve the synthesis problem is explicitly constructed. The delay-dependent stability conditions we obtained can be described in terms of nonstrict linear matrix inequalities (LMIs, which are much more convenient to be solved by LMI tools.

  19. Indoor Positioning for Smartphones Using Asynchronous Ultrasound Trilateration

    Directory of Open Access Journals (Sweden)

    James D. Carswell

    2013-06-01

    Full Text Available Modern smartphones are a great platform for Location Based Services (LBS. While outdoor LBS for smartphones has proven to be very successful, indoor LBS for smartphones has not yet fully developed due to the lack of an accurate positioning technology. In this paper we present an accurate indoor positioning approach for commercial off-the-shelf (COTS smartphones that uses the innate ability of mobile phones to produce ultrasound, combined with Time-Difference-of-Arrival (TDOA asynchronous trilateration. We evaluate our indoor positioning approach by describing its strengths and weaknesses, and determine its absolute accuracy. This is accomplished through a range of experiments that involve variables such as position of control point microphones, position of phone within the room, direction speaker is facing and presence of user in the signal path. Test results show that our Lok8 (locate mobile positioning system can achieve accuracies better than 10 cm in a real-world environment.

  20. Normalized and Asynchronous Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; Balbo, M; Bergmann, M; Biland, A; Blank, M; Bretz, T; Bruegge, K A; Buss, J; Domke, M; Dorner, D; Einecke, S; Hempfling, C; Hildebrand, D; Hughes, G; Lustermann, W; Mannheim, K; Mueller, S A; Neise, D; Neronov, A; Noethe, M; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Shukla, A; Temme, F; Thaele, J; Toscano, S; Vogler, P; Walter, R; Wilbert, A

    2016-01-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it ca...

  1. Asynchronous extinction of late Quaternary sloths on continents and islands

    Science.gov (United States)

    Steadman, David W.; Martin, Paul S.; MacPhee, Ross D. E.; Jull, A. J. T.; McDonald, H. Gregory; Woods, Charles A.; Iturralde-Vinent, Manuel; Hodgins, Gregory W. L.

    2005-01-01

    Whatever the cause, it is extraordinary that dozens of genera of large mammals became extinct during the late Quaternary throughout the Western Hemisphere, including 90% of the genera of the xenarthran suborder Phyllophaga (sloths). Radiocarbon dates directly on dung, bones, or other tissue of extinct sloths place their “last appearance” datum at ≈11,000 radiocarbon years before present (yr BP) or slightly less in North America, ≈10,500 yr BP in South America, and ≈4,400 yr BP on West Indian islands. This asynchronous situation is not compatible with glacial–interglacial climate change forcing these extinctions, especially given the great elevational, latitudinal, and longitudinal variation of the sloth-bearing continental sites. Instead, the chronology of last appearance of extinct sloths, whether on continents or islands, more closely tracks the first arrival of people. PMID:16085711

  2. The Efficacy of Deliberate Practice Delivered Using Asynchronous Training Technology

    Directory of Open Access Journals (Sweden)

    Colleen E. McEdwards

    2014-04-01

    Full Text Available Employee productivity is key to survival in business. Senior employees require access to advanced training that does not necessitate extended periods away from their work. Once performance begins to plateau, it can be difficult to reach experienced employees with cost-effective, timely, and relevant training opportunities. Organizations must find ways to enhance employee performance; however, research suggests workplace training is too expensive and is too often without lasting benefit. The purpose of this study is to further quantify deliberate practice as a potentially efficient, customizable mode of training using asynchronous e-learning. The study compared traditional seminars with online deliberate practice training. While additional research is needed in wider learning contexts and with larger sample sizes, improvements among the deliberate practice groups were significant. Using a mixed methods pretest/posttest research design, the deliberate practice training showed improved performance and increased satisfaction compared with the traditional seminar approach.

  3. Leader Election for Anonymous Asynchronous Agents in Arbitrary Networks

    CERN Document Server

    Dereniowski, Dariusz

    2012-01-01

    We study the problem of leader election among mobile agents operating in an arbitrary network modeled as an undirected graph. Nodes of the network are unlabeled and all agents are identical. Hence the only way to elect a leader among agents is by exploiting asymmetries in their initial positions in the graph. Agents do not know the graph or their positions in it, hence they must gain this knowledge by navigating in the graph and share it with other agents to accomplish leader election. This can be done using meetings of agents, which is difficult because of their asynchronous nature: an adversary has total control over the speed of agents. When can a leader be elected in this adversarial scenario and how to do it? We give a complete answer to this question by characterizing all initial configurations for which leader election is possible and by constructing an algorithm that accomplishes leader election for all configurations for which this can be done.

  4. Asynchronous learning: student utilization out of sync with their preference

    Directory of Open Access Journals (Sweden)

    Edward K. Lew

    2016-06-01

    Full Text Available Background: Asynchronous learning is gaining popularity. Data are limited regarding this learning method in medical students rotating in emergency medicine (EM. In EM, faculty time is limited to give in-person lectures. The authors sought to create an online curriculum that students could utilize as an additional learning modality. Objective: The goal was to evaluate effectiveness, participation, and preference for this mode of learning. Methods: We developed five online, narrated PowerPoint presentations. After orientation, access to the online curriculum was provided to the students, which they could review at their leisure. Results: One hundred and seven fourth-year medical students participated. They reported the curriculum to be of high quality. Pretest scores were similar for those that viewed all lectures – compliant group (CG (9.5 [CI 4.8–14.1] and those that did not view any – non-compliant group (NCG (9.6 [CI 5.9–13.4]. There was no statistical significant difference in posttest scores between the groups although there was improvement overall: CG 14.6 (CI 6.9–22.1; NCG 11.4 (CI 5.7–17.1. A majority (69.2% favored inclusion of asynchronous learning, but less than a quarter (22.4% reported viewing all five modules and more than a third (36.4% viewed none. Conclusion: Despite student-expressed preference for an online curriculum, they used the online resource less than expected. This should give pause to educators looking to convert core EM topics to an online format. However, when high-quality online lectures are utilized as a learning tool, this study demonstrates that they had neither a positive nor a negative impact on test scores.

  5. Argo: A Time-Elastic Time-Division-Multiplexed NOC using Asynchronous Routers

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens

    2014-01-01

    In this paper we explore the use of asynchronous routers in a time-division-multiplexed (TDM) network-on-chip (NOC), Argo, that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs...... are either synchronous or mesochronous. We use asynchronous routers to achieve a simpler, smaller, and more robust, self-timed design. Our design exploits the fact that pipelined asynchronous circuits also behave as ripple FIFOs. Thus, it avoids the need for explicit synchronization FIFOs between the routers...

  6. IMPLEMENTATION MODEL OF MOTOR TRACTION FORCE OF MAGLEV TRAIN

    Directory of Open Access Journals (Sweden)

    V. O. Polyakov

    2016-08-01

    Full Text Available Purpose. Traction force implementation (TFI by the motor of magnetic levitation train (MLT occurs in the process of electric-to-kinetic energy transformation at interaction of inductor and armature magnetic fields. Ac-cordingly, the aim of this study is to obtain a correct description of such energy transformation. Methodology. At the present stage, a mathematical and, in particular, computer simulation is the main and most universal tool for analysis and synthesis of processes and systems. At the same time, radical advantages of this tool make the precision of selection of a particular research methodology even more important. It is especially important for such a large and complex system as MLT. Therefore the special attention in the work is given to the rationale for choosing the research paradigm selective features. Findings. The analysis results of existing TFI process model versions indicate that each of them has both advantages and disadvantages. Therefore, one of the main results of this study was the creation of a mathematical model for such process that would preserve the advantages of previous versions, but would be free from their disadvantages. The work provides rationale for application (for the purposes of research of train motor TFI of the integrative holistic paradigm, which assimilates the advantages of the theory of electric circuit and magnetic field. Originality. The priority of creation of such paradigm and corresponding version of FI model constitute the originality of the research. Practical value. The main manifestation of practical value of this research in the opportunity, in case of use of its results, for significant increase in efficiency of MLT dynamic studies, on the condition that their generalized costs will not rise.

  7. "The effect of halo traction between anterior and posterior spinal fusion on the correction of scoliosis "

    Directory of Open Access Journals (Sweden)

    Behtash H

    2007-04-01

    Full Text Available Background: The currently accepted treatment of scoliosis are bracing and surgery. Two-stage anterior and posterior spinal fusion is used to correct scoliosis. It seems that the application of a longitudinal force to the axis of the spinal column as a means of stabilizing by halo traction, may increase the correction of the curve. The aim of this study was to evaluate the effect of halo traction used between the two stages of corrective surgery, anterior and posterior spinal fusion, on the correction of scoliosis curvature. Methods: In this randomized clinical trial twelve scoliotic patients, aged from 12-19 years old, were treated by two-stage anterior spinal release and fusion (ASF and posterior spinal fusion (PSF. The patients were divided in two groups: 6 scoliotic patients without any traction between ASF and PSF surgeries (group A, and 6 scoliotic patients were undergone halo traction for one week between ASF and PSF surgeries (group B. Major curve angle was measured before surgery, one week after ASF and one year after PSF surgeries. Data were collected and analyzed using SPSS v.13.5. Results: The mean baseline curve angles were 90° (SD=18.70 and 94.17°(SD=28.18 in groups A and B, respectively. Whereas, the mean final curve angles (one year after PSF were 51.17°(SD=29.59 and 39.17°(23.11 in groups A and B, respectively. Final angle improvement was 46.58% (SD=20.31 in patients without traction and 61.32% (SD=14.02 in patients with halo traction. The major curve angles showed significantly better correction in patients with traction one week after ASF [38.67°(SD=7.86 vs. 25°(SD=6.28, P=0.012]. This difference persisted at the end of the first year after operation. [55°(SD=8.94 vs. 38.83°(SD=11.65, P=0.022]. Conclusion: Application of halo traction between ASF and PSF surgeries may lead to better improvement of the scoliotic curvature and short time application of halo traction decreases possible complications.

  8. DEVELOPMENT OF METHODS OF CALCULATION OF TRACTION POWER SUPPLY SYSTEMS AND ENERGY SYSTEMS FEEDING THEM

    Directory of Open Access Journals (Sweden)

    I.V. Domanskyi

    2015-08-01

    Full Text Available Currently, the cause deterioration of quality rating of electricity on tire traction substations AC can be either how mode of operation of power systems, industrial loads so and the impact of electric traction. The experience of energy surveys show that the loss from flow potential equalization currents in each the third plot between traction substations AC is amount to not less than 250 thousand kW∙h per year. To select the optimum power and places location of the device longitudinal capacitive of compensation and decision other tasks it is necessary methodology of systems of calculation that takes into account the complex nature of the mutual influence of the quality of the electricity coming from the energy system of and the transportation process. In the paper proposed three options for calculation algorithms modes work of existing and perspective systems, traction power supply AC jointly with power supply their by energy systems, including the algorithm for calculating networks of different nominal voltages using the transformations; decomposition and synthesis of networks with different voltage levels; the iterations and probabilistic assessment of the impact of power mains. Developed the schemes formalization of graphs and the matrices of portions of the outer and traction power supply and method of selecting parameters and places location of the devices longitudinal capacitive of compensation, which are based on direct methods solving systems of linear algebraic equations with a dense banded and profile-sparse the matrix. Are generalized ways of formation and transformation of graphs of schemes traction power supply and feeding them energy systems and proposed the method of calculation the complex the moment of schemes, which increases the accuracy of calculating of flows power on traction networks to 1-2 % and allows you to select the optimal parameters and places location of the devices longitudinal capacitive of compensation

  9. EFFECTIVENESS OF NEURODYNAMICS IN COMPARISON TO MANUAL TRACTION IN THE MANAGEMENT OF CERVICAL RADICULOPATHY

    Directory of Open Access Journals (Sweden)

    Mamoona Anwar

    2016-06-01

    Full Text Available Background: Cervical radiculopathy is a condition of pain and sensorimotor deficits due to cervical nerve root compression. The symptoms may include weakness, tingling, numbness and pain. C6, C7 nerve roots are most involved in cervical radiculopathy. Various modalities and therapeutic interventions are used and recommended for management of cervical radiculopathy including cervical collars, immobilization, manipulation, cervical traction TENS and therapeutic exercises.The aimof this study is to evaluate the efficacy of neurodynamics in comparison to manual traction in the management of cervical radiculopathy. Methods: An Interventional research was performed in the Department of Physiotherapy, Mayo hospital Lahore, Pakistan. 40 subjects aged between 18-60 years participated in the study. They were divided into two groups namely Group A and Group B with 20 subjects in each group. The duration of the study was 4 weeks with 4 sessions per week. GroupA received neurodynamics along with strengthening exercises while Group B received manual traction along with strengthening exercises. Neck Disability Index (NDI scale was used as an outcome measure andpaired sample t-test was used for statistical analysis. Results: A significant improvement was found in both neurodynamics group and manual traction group for pain and functional status with p value< 0.05. Conclusion: This study concluded that the treatment techniques, neurodynamics and manual traction were effective in alleviating the symptoms associated with cervical radiculopathy in terms of decreasing pain intensity, increasing ranges of motion and improving functional capacity.

  10. Free Form Deformation-Based Image Registration Improves Accuracy of Traction Force Microscopy.

    Directory of Open Access Journals (Sweden)

    Alvaro Jorge-Peñas

    Full Text Available Traction Force Microscopy (TFM is a widespread method used to recover cellular tractions from the deformation that they cause in their surrounding substrate. Particle Image Velocimetry (PIV is commonly used to quantify the substrate's deformations, due to its simplicity and efficiency. However, PIV relies on a block-matching scheme that easily underestimates the deformations. This is especially relevant in the case of large, locally non-uniform deformations as those usually found in the vicinity of a cell's adhesions to the substrate. To overcome these limitations, we formulate the calculation of the deformation of the substrate in TFM as a non-rigid image registration process that warps the image of the unstressed material to match the image of the stressed one. In particular, we propose to use a B-spline -based Free Form Deformation (FFD algorithm that uses a connected deformable mesh to model a wide range of flexible deformations caused by cellular tractions. Our FFD approach is validated in 3D fields using synthetic (simulated data as well as with experimental data obtained using isolated endothelial cells lying on a deformable, polyacrylamide substrate. Our results show that FFD outperforms PIV providing a deformation field that allows a better recovery of the magnitude and orientation of tractions. Together, these results demonstrate the added value of the FFD algorithm for improving the accuracy of traction recovery.

  11. The regulation of traction force in relation to cell shape and focal adhesions.

    Science.gov (United States)

    Rape, Andrew D; Guo, Wei-Hui; Wang, Yu-Li

    2011-03-01

    Mechanical forces provide critical inputs for proper cellular functions. The interplay between the generation of, and response to, mechanical forces regulate such cellular processes as differentiation, proliferation, and migration. We postulate that adherent cells respond to a number of physical and topographical factors, including cell size and shape, by detecting the magnitude and/or distribution of traction forces under different conditions. To address this possibility we introduce a new simple method for precise micropatterning of hydrogels, and then apply the technique to systematically investigate the relationship between cell geometry, focal adhesions, and traction forces in cells with a series of spread areas and aspect ratios. Contrary to previous findings, we find that traction force is not determined primarily by the cell spreading area but by the distance from cell center to the perimeter. This distance in turn controls traction forces by regulating the size of focal adhesions, such that constraining the size of focal adhesions by micropatterning can override the effect of geometry. We propose that the responses of traction forces to center-periphery distance, possibly through a positive feedback mechanism that regulates focal adhesions, provide the cell with the information on its own shape and size. A similar positive feedback control may allow cells to respond to a variety of physical or topographical signals via a unified mechanism. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Free Form Deformation–Based Image Registration Improves Accuracy of Traction Force Microscopy

    Science.gov (United States)

    Jorge-Peñas, Alvaro; Izquierdo-Alvarez, Alicia; Aguilar-Cuenca, Rocio; Vicente-Manzanares, Miguel; Garcia-Aznar, José Manuel; Van Oosterwyck, Hans; de-Juan-Pardo, Elena M.; Ortiz-de-Solorzano, Carlos; Muñoz-Barrutia, Arrate

    2015-01-01

    Traction Force Microscopy (TFM) is a widespread method used to recover cellular tractions from the deformation that they cause in their surrounding substrate. Particle Image Velocimetry (PIV) is commonly used to quantify the substrate’s deformations, due to its simplicity and efficiency. However, PIV relies on a block-matching scheme that easily underestimates the deformations. This is especially relevant in the case of large, locally non-uniform deformations as those usually found in the vicinity of a cell’s adhesions to the substrate. To overcome these limitations, we formulate the calculation of the deformation of the substrate in TFM as a non-rigid image registration process that warps the image of the unstressed material to match the image of the stressed one. In particular, we propose to use a B-spline -based Free Form Deformation (FFD) algorithm that uses a connected deformable mesh to model a wide range of flexible deformations caused by cellular tractions. Our FFD approach is validated in 3D fields using synthetic (simulated) data as well as with experimental data obtained using isolated endothelial cells lying on a deformable, polyacrylamide substrate. Our results show that FFD outperforms PIV providing a deformation field that allows a better recovery of the magnitude and orientation of tractions. Together, these results demonstrate the added value of the FFD algorithm for improving the accuracy of traction recovery. PMID:26641883

  13. [Effect of Pinch-3 gene interference of glomerular podocytes on cell morphology and cell traction force].

    Science.gov (United States)

    Yang, Yu; Niu, Qingyuan; Ji, Zhenling; Zhang, Jingjing; Li, Jianting; Ma, Deshun

    2013-06-01

    Pinch-3 protein is an important constituent of cell membranes, which directly affects the cell morphology and mechanical properties. We observed and compared the change of morphology and cell traction force of glomerular podocytes before and after Pinch-3 gene inhibition by gene interference technology in this experiment. We found that a number of pores appeared on the cell surface, and the cell projected area were increased at the same time, with an approximate average about an increase of 40% after Pinch-3 gene inhibition. The results showed that the cell traction force of glomerular podocytes was significantly reduced, with an approximate average decrease of 40%, the maximum value of the cell traction force was reduced and the distribution of cell traction force became dispersive. All this suggested that after Pinch-3 gene inhibition, some pores created on the cell surface influenced the physical properties of glomerular podocytes and then affected the cell projected area and influenced the formation and distribution of cell traction force of the glomerular podocytes as well.

  14. For whom the cells pull: Hydrogel and micropost devices for measuring traction forces.

    Science.gov (United States)

    Ribeiro, Alexandre J S; Denisin, Aleksandra K; Wilson, Robin E; Pruitt, Beth L

    2016-02-01

    While performing several functions, adherent cells deform their surrounding substrate via stable adhesions that connect the intracellular cytoskeleton to the extracellular matrix. The traction forces that deform the substrate are studied in mechanotrasduction because they are affected by the mechanics of the extracellular milieu. We review the development and application of two methods widely used to measure traction forces generated by cells on 2D substrates: (i) traction force microscopy with polyacrylamide hydrogels and (ii) calculation of traction forces with arrays of deformable microposts. Measuring forces with these methods relies on measuring substrate displacements and converting them into forces. We describe approaches to determine force from displacements and elaborate on the necessary experimental conditions for this type of analysis. We emphasize device fabrication, mechanical calibration of substrates and covalent attachment of extracellular matrix proteins to substrates as key features in the design of experiments to measure cell traction forces with polyacrylamide hydrogels or microposts. We also report the challenges and achievements in integrating these methods with platforms for the mechanical stimulation of adherent cells. The approaches described here will enable new studies to understand cell mechanical outputs as a function of mechanical inputs and advance the understanding of mechanotransduction mechanisms.

  15. A reverse mode of three-phase asynchronous motors with hexaphase windings

    Directory of Open Access Journals (Sweden)

    V.D. Lushchyk

    2014-04-01

    Full Text Available A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.

  16. Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

    OpenAIRE

    Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

    2008-01-01

    Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

  17. Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

    NARCIS (Netherlands)

    Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

    2008-01-01

    Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

  18. Mathematical Description of an Asynchronous Motor with the Indirect Control of the Output Mechanical Variables

    Directory of Open Access Journals (Sweden)

    Glazachev A.V.

    2016-01-01

    Full Text Available The article gives the mathematical description of an asynchronous motor with the indirect control of the output mechanical variables of an asynchronous motor in the electric drive. To determine the electromagnetic torque and angular velocity of the asynchronous motor in the electric drive the mathematical description is used in which the values are determined by the readings of the motor and easily measured values by means of known in practice devices. The proposed in the article the mathematical description for the indirect measuring the electromagnetic torque and angular velocity of the asynchronous motor in the electric drive does not contain the integral components that introduce the great error into the value of the controlled electromagnetic torque and angular velocity.

  19. ZONES OF STEADY CAPACITOR EXCITATION IN A MODE OF GENERATION OF TYPICAL ASYNCHRONOUS MACHINES

    Directory of Open Access Journals (Sweden)

    Postoronca Sv.

    2009-12-01

    Full Text Available In work some features of a mode of capacitor excitation of industrial asynchronous electric motors, and also generators made on their base which can be used in wind installations of low power are considered. Borders of zones of steady capacitor excitation of asynchronous electric motors in rated power of 0,25-22,0 kW and generators made on their base, and also character of influence of own losses and active capacity of loading of the equivalent circuit of the asynchronous machine resulted in parameters have been determined. Some recommendations after maintenance of stability of capacitor excitation of asynchronous machines for work in a mode of generation of electric energy are given.

  20. Asynchronous Sensor fuSion for Improved Safety of air Traffic (ASSIST) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI proposes to develop, implement and test a collision detection system for unmanned aerial vehicles (UAV), referred to as the Asynchronous Sensor fuSion for...

  1. Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

    DEFF Research Database (Denmark)

    Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.

    2016-01-01

    We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

  2. Training-Based Schemes are Suboptimal for High Rate Asynchronous Communication

    CERN Document Server

    Chandar, Venkat; Wornell, Gregory W

    2009-01-01

    We consider asynchronous point-to-point communication. Building on a recently developed model, we show that training based schemes, i.e., communication strategies that separate synchronization from information transmission, perform suboptimally at high rate.

  3. Low-power Implementation of an Encryption/Decryption System with Asynchronous Techniques

    Directory of Open Access Journals (Sweden)

    Nikos Sklavos

    2002-01-01

    Full Text Available An asynchronous VLSI implementation of the International Data Encryption Algorithm (IDEA is presented in this paper. In order to evaluate the asynchronous design a synchronous version of the algorithm was also designed. VHDL hardware description language was used in order to describe the algorithm. By using Synopsys commercial available tools the VHDL code was synthesized. After placing and routing both designs were fabricated with 0.6 μm CMOS technology. With a system clock of up to 8 MHz and a power supply of 5 V the two chips were tested and evaluated comparing with the software implementation of the IDEA algorithm. This new approach proves efficiently the lowest power consumption of the asynchronous implementation compared to the existing synchronous. Therefore, the asynchronous chip performs efficiently in Wireless Encryption Protocols and high speed networks.

  4. Distributed Consensus of Stochastic Delayed Multi-agent Systems Under Asynchronous Switching.

    Science.gov (United States)

    Wu, Xiaotai; Tang, Yang; Cao, Jinde; Zhang, Wenbing

    2016-08-01

    In this paper, the distributed exponential consensus of stochastic delayed multi-agent systems with nonlinear dynamics is investigated under asynchronous switching. The asynchronous switching considered here is to account for the time of identifying the active modes of multi-agent systems. After receipt of confirmation of mode's switching, the matched controller can be applied, which means that the switching time of the matched controller in each node usually lags behind that of system switching. In order to handle the coexistence of switched signals and stochastic disturbances, a comparison principle of stochastic switched delayed systems is first proved. By means of this extended comparison principle, several easy to verified conditions for the existence of an asynchronously switched distributed controller are derived such that stochastic delayed multi-agent systems with asynchronous switching and nonlinear dynamics can achieve global exponential consensus. Two examples are given to illustrate the effectiveness of the proposed method.

  5. Asynchronous abdomino-parasacral resection of a giant pelvic lipoma protruding to the left buttock

    Directory of Open Access Journals (Sweden)

    Masanori Sato

    2014-01-01

    CONCLUSION: The asynchronous abdomino-parasacral approach with several turnings of the patient's body and plastic bag packing of the tumor were advantageous to manage en bloc resection of the giant pelvic lipoma presented in this case study.

  6. A novel fuzzy logic correctional algorithm for traction control systems on uneven low-friction road conditions

    Science.gov (United States)

    Li, Liang; Ran, Xu; Wu, Kaihui; Song, Jian; Han, Zongqi

    2015-06-01

    The traction control system (TCS) might prevent excessive skid of the driving wheels so as to enhance the driving performance and direction stability of the vehicle. But if driven on an uneven low-friction road, the vehicle body often vibrates severely due to the drastic fluctuations of driving wheels, and then the vehicle comfort might be reduced greatly. The vibrations could be hardly removed with traditional drive-slip control logic of the TCS. In this paper, a novel fuzzy logic controller has been brought forward, in which the vibration signals of the driving wheels are adopted as new controlled variables, and then the engine torque and the active brake pressure might be coordinately re-adjusted besides the basic logic of a traditional TCS. In the proposed controller, an adjustable engine torque and pressure compensation loop are adopted to constrain the drastic vehicle vibration. Thus, the wheel driving slips and the vibration degrees might be adjusted synchronously and effectively. The simulation results and the real vehicle tests validated that the proposed algorithm is effective and adaptable for a complicated uneven low-friction road.

  7. Universal asynchronous RSFQ gate for realization of Boolean functions of dual-rail binary variables

    Energy Technology Data Exchange (ETDEWEB)

    Dimov, B [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany); Khabipov, M [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Balashov, D [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Brandt, C M [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Ortlepp, Th [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany); Hagedorn, D [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Buchholz, F-Im [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Niemeyer, J [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Uhlmann, F H [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany)

    2006-06-01

    We report on the design, optimization, fabrication, and successful testing of an universal asynchronous RSFQ logic gate based on the dual-rail data coding. Properly connecting its inputs and outputs, one can perform most of the basic Boolean functions over a pair of dual-rail input variables. Therefore, this gate is fundamental component for the development of high-speed complex asynchronous RSFQ digital devices.

  8. Computationally Efficient Blind Code Synchronization for Asynchronous DS-CDMA Systems with Adaptive Antenna Arrays

    OpenAIRE

    Chia-Chang Hu

    2005-01-01

    A novel space-time adaptive near-far robust code-synchronization array detector for asynchronous DS-CDMA systems is developed in this paper. There are the same basic requirements that are needed by the conventional matched filter of an asynchronous DS-CDMA system. For the real-time applicability, a computationally efficient architecture of the proposed detector is developed that is based on the concept of the multistage Wiener filter (MWF) of Goldstein and Reed. This multistage technique resu...

  9. INVESTIGATION OF ASYNCHRONOUS OPTICAL COMMUNICATION CHANNEL THROUGHPUT CONTAINING A RECEIVER ON THE BASIS OF PHOTON COUNTER

    Directory of Open Access Journals (Sweden)

    I. R. Gulakov

    2013-01-01

    Full Text Available A mathematical model of asynchronous optical communication channel with a photon counter applied as a receiving module has been built. The expression for calculating of data throughput of this channel has been obtained. As a result of implemented experimental investigations it has been established that the data throughput of asynchronous optical communication channel containing a photon counter on the basis of avalanche photodetector as a receiving module depends on optical radiation and photodetector supply voltage.

  10. D-MG Tradeoff of DF and AF Relaying Protocols over Asynchronous PAM Cooperative Networks

    OpenAIRE

    Torbatian, Mehdi; Damen, Mohamed Oussama

    2009-01-01

    The diversity multiplexing tradeoff of a general two-hop asynchronous cooperative network is examined for various relaying protocols such as non-orthogonal selection decode-and-forward (NSDF), orthogonal selection decode-and-forward (OSDF), non-orthogonal amplify-and-forward (NAF), and orthogonal amplify-and-forward (OAF). The transmitter nodes are assumed to send pulse amplitude modulation (PAM) signals asynchronously, in which information symbols are linearly modulated by a shaping waveform...

  11. An Evaluation of Parallel Synchronous and Conservative Asynchronous Logic-Level Simulations

    Directory of Open Access Journals (Sweden)

    Ausif Mahmood

    1996-01-01

    a circuit remain fixed during the entire simulation. We remove this limitation and, by extending the analyses to multi-input, multi-output circuits with an arbitrary number of input events, show that the conservative asynchronous simulation extracts more parallelism and executes faster than synchronous simulation in general. Our conclusions are supported by a comparison of the idealized execution times of synchronous and conservative asynchronous algorithms on ISCAS combinational and sequential benchmark circuits.

  12. Violation of the equivalence principle for stressed bodies in asynchronous relativity

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Martins, R. de (Centro de Logica, Epistemologia e Historia da Ciencia, Campinas (Brazil))

    1983-12-11

    In the recently developed asynchronous formulation of the relativistic theory of extended bodies, the inertial mass of a body does not explicitly depend on its pressure or stress. The detailed analysis of the weight of a box filled with a gas and placed in a weak gravitational field shows that this feature of asynchronous relativity implies a breakdown of the equivalence between inertial and passive gravitational mass for stressed systems.

  13. Design of the Buffer Structure of Traction Running with a Constant Speed%恒定速度牵引运行的缓冲结构设计

    Institute of Scientific and Technical Information of China (English)

    罗茜; 曾宪任

    2013-01-01

    This paper mainly aimed to study buffer structure design on the traction transport system when the traction transport boundary conditions were given.With such conditions as the maximum impact force,traction speed,maximum speed of alluvium,the elasticity coefficient and the mass of buffer structure,a mathematical model was established and the solution of differential equations was solved.At last,a program was compiled with MATLAB language.With this program the elasticity coefficient and the maximum impact force which meet the requirements in impact process could be solved as long as the boundary conditions were input.This provided a quick design basis of buffer structure for most mechanical engineers.%主要研究牵引运输中的缓冲结构设计;通过对给定的牵引运输的边界条件:最大冲击作用力、牵引速度、冲击物最大速度、缓冲结构弹性系数及质量,建立数学模型,求解微分方程,得到问题的解;最后通过MATLAB语言对问题的求解过程进行了程序设计,只要将边界条件输入,就可以解出满足要求的缓冲结构的弹性系数及冲击过程的最大冲击力。给广大机械设计人员提供了快速的缓冲结构设计依据。

  14. Non-regularised Inverse Finite Element Analysis for 3D Traction Force Microscopy

    CERN Document Server

    Munoz, Jose J

    2016-01-01

    The tractions that cells exert on a gel substrate from the observed displacements is an increasingly attractive and valuable information in biomedical experiments. The computation of these tractions requires in general the solution of an inverse problem. Here, we resort to the discretisation with finite elements of the associated direct variational formulation, and solve the inverse analysis using a least square approach. This strategy requires the minimisation of an error functional, which is usually regularised in order to obtain a stable system of equations with a unique solution. In this paper we show that for many common three-dimensional geometries, meshes and loading conditions, this regularisation is unnecessary. In these cases, the computational cost of the inverse problem becomes equivalent to a direct finite element problem. For the non-regularised functional, we deduce the necessary and sufficient conditions that the dimensions of the interpolated displacement and traction fields must preserve in ...

  15. Some effects of grooved runway configurations on aircraft tire braking traction under flooded runway conditions

    Science.gov (United States)

    Byrdsong, T. A.

    1973-01-01

    An experimental investigation was conducted to study the effect of grooved runway configurations on aircraft tire braking traction on flooded runway surfaces. The investigation was performed, utilizing size 49 x 17, type VII, aircraft tires with an inflation pressure of 170 lb per square inch at ground speeds up to approximately 120 knots. The results of this investigation indicate that when the runway is flooded, grooved surfaces provide better braking traction than an ungrooved surface and, in general, the level of braking traction was found to improve as the tire bearing pressure was increased because of an increase in the groove area of either the surface or the tire tread. Rounding the groove edges tended to degrade the tire braking capability from that developed on the same groove configuration with sharp edges. Results also indicate that braking friction coefficients for the test tires and runway surfaces decreased as ground speed was increased because of the hydroplaning effects.

  16. Bayesian Network Based Fault Prognosis via Bond Graph Modeling of High-Speed Railway Traction Device

    Directory of Open Access Journals (Sweden)

    Yunkai Wu

    2015-01-01

    component-level faults accurately for a high-speed railway traction system, a fault prognosis approach via Bayesian network and bond graph modeling techniques is proposed. The inherent structure of a railway traction system is represented by bond graph model, based on which a multilayer Bayesian network is developed for fault propagation analysis and fault prediction. For complete and incomplete data sets, two different parameter learning algorithms such as Bayesian estimation and expectation maximization (EM algorithm are adopted to determine the conditional probability table of the Bayesian network. The proposed prognosis approach using Pearl’s polytree propagation algorithm for joint probability reasoning can predict the failure probabilities of leaf nodes based on the current status of root nodes. Verification results in a high-speed railway traction simulation system can demonstrate the effectiveness of the proposed approach.

  17. Evaluation of Stress Intensity Factors for Multiple Cracked Circular Disks Under Crack Surface Tractions with SBFEM

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-yu; LIN Gao; LI Xiao-chuan; XU Feng-lin

    2013-01-01

    Stress intensity factors (SIFs) for the cracked circular disks under different distributing surface tractions are evaluated with the scaled boundary finite element method (SBFEM).In the SBFEM,the analytical advantage of the solution in the radial direction allows SIFs to be directly determined from its definition,therefore no special crack-tip treatment is necessary.Furthermore anisotropic material behavior can be treated easily.Different distributions of surface tractions are considered for the center and double-edge-cracked disks.The benchmark examples are modeled and an excellent agreement between the results in the present study and those in published literature is found.It shows that SBFEM is effective and possesses high accuracy.The SIFs of the cracked orthotropic material circular disks subjected to different surface tractions are also evaluated.The technique of substructure is applied to handle the multiple cracks problem.

  18. Traction endurance biomechanical study of metallic suture anchors at different insertion angles

    Directory of Open Access Journals (Sweden)

    Azato Flávia Namie

    2003-01-01

    Full Text Available The suture anchors' insertion angle and its traction resistance are the main subjects of this study. Twenty trials were realized using threaded suture anchors in four diferents angulations (30º /45º /60º /90º in human bone (distal femur and another twenty trials in artificial bone (SawboneTM. The anchors were pulled out being tractioned uprightly from its bone surface by a Kratos Universal test machine. The human bone results found no relation between the main subjects of this study, so whithout statistical value. On the other hand at the artificial bone the insertion angle of 90º beared more traction, being statistically significant compared to the other angles.

  19. Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface

    Directory of Open Access Journals (Sweden)

    Chin Fhong Soon

    2015-01-01

    Full Text Available Cell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT system can be used in conjunction with a bespoke cell traction force mapping (CTFM software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated that the system could be used to monitor the generation of cell/surface forces in an initially quiescent cell, as it migrated over the culture substrate, via multiple points of contact between the cell and the surface. Future application of this system is the real-time assaying of the pharmacological effects of cytokines on the mechanics of cell migration.

  20. Tracking traction force changes of single cells on the liquid crystal surface.

    Science.gov (United States)

    Soon, Chin Fhong; Tee, Kian Sek; Youseffi, Mansour; Denyer, Morgan C T

    2015-01-05

    Cell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT) system can be used in conjunction with a bespoke cell traction force mapping (CTFM) software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated that the system could be used to monitor the generation of cell/surface forces in an initially quiescent cell, as it migrated over the culture substrate, via multiple points of contact between the cell and the surface. Future application of this system is the real-time assaying of the pharmacological effects of cytokines on the mechanics of cell migration.

  1. An Inverter Packaging Scheme for an Integrated Segmented Traction Drive System

    Energy Technology Data Exchange (ETDEWEB)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL; Ayers, Curtis William [ORNL; Wiles, Randy H [ORNL

    2013-01-01

    The standard voltage source inverter (VSI), widely used in electric vehicle/hybrid electric vehicle (EV/HEV) traction drives, requires a bulky dc bus capacitor to absorb the large switching ripple currents and prevent them from shortening the battery s life. The dc bus capacitor presents a significant barrier to meeting inverter cost, volume, and weight requirements for mass production of affordable EVs/HEVs. The large ripple currents become even more problematic for the film capacitors (the capacitor technology of choice for EVs/HEVs) in high temperature environments as their ripple current handling capability decreases rapidly with rising temperatures. It is shown in previous work that segmenting the VSI based traction drive system can significantly decrease the ripple currents and thus the size of the dc bus capacitor. This paper presents an integrated packaging scheme to reduce the system cost of a segmented traction drive.

  2. Head-Down Tilt with Balanced Traction as a Model for Simulating Spinal Acclimation to Microgravity

    Science.gov (United States)

    Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.; Fechner, K.; Haruna, Y.; Kahan, N. J.; Hargens, A. R.

    1994-01-01

    Astronauts experience total body height increases of 4 to 7 cm in microgravity. Thus, stretching of the spinal cord, nerve roots, and muscular and ligamentous tissues may be responsible for the hyperreflexia, back pain, and muscular atrophy associated with exposure to microgravity. Axial compression of the spine makes 6 deg. head-down tilt (HDT) an unsuitable model for spinal acclimation to microgravity. However, this axial compression may be counteracted by balanced traction consisting of 10% body weight (sin 6 deg. = 0.1) applied to the legs. Six healthy male subjects underwent 3 days each of 60 HDT with balanced traction and horizontal bed rest (HBR), with a 2 week recovery period between treatments. Total body and spine length, lumbar disc height, back pain, erector spinae intramuscular pressure, and ankle joint torque were measured before, during and after each treatment. Total body and spine (processes of L5 - C7) lengths increased significantly more during HDT with balanced traction (22 +/- 8 mm and 25 +/- 8 mm, respectively) than during HBR (16 +/- 4 mm and 14 +/- 9 mm, respectively). Back and leg pain were significantly greater during HDT with balanced traction than during HBR. The distance between the lower end plate of L4 and the upper endplate of S1, as measured by sonography, increased significantly in both treatments to the same degree (2.9 +/- 1.9 mm, HDT with balanced traction; 3.3 +/- 1.5 mm, HBR). Intramuscular pressure of the erector spinae muscles and maximal ankle joint torque were unaltered with both models. While neither model increased height to the magnitude observed in microgravity, HDT with balanced traction may be a better model for simulating the body lengthening and back pain experienced in microgravity.

  3. A novel cell traction force microscopy to study multi-cellular system.

    Directory of Open Access Journals (Sweden)

    Xin Tang

    2014-06-01

    Full Text Available Traction forces exerted by adherent cells on their microenvironment can mediate many critical cellular functions. Accurate quantification of these forces is essential for mechanistic understanding of mechanotransduction. However, most existing methods of quantifying cellular forces are limited to single cells in isolation, whereas most physiological processes are inherently multi-cellular in nature where cell-cell and cell-microenvironment interactions determine the emergent properties of cell clusters. In the present study, a robust finite-element-method-based cell traction force microscopy technique is developed to estimate the traction forces produced by multiple isolated cells as well as cell clusters on soft substrates. The method accounts for the finite thickness of the substrate. Hence, cell cluster size can be larger than substrate thickness. The method allows computing the traction field from the substrate displacements within the cells' and clusters' boundaries. The displacement data outside these boundaries are not necessary. The utility of the method is demonstrated by computing the traction generated by multiple monkey kidney fibroblasts (MKF and human colon cancerous (HCT-8 cells in close proximity, as well as by large clusters. It is found that cells act as individual contractile groups within clusters for generating traction. There may be multiple of such groups in the cluster, or the entire cluster may behave a single group. Individual cells do not form dipoles, but serve as a conduit of force (transmission lines over long distances in the cluster. The cell-cell force can be either tensile or compressive depending on the cell-microenvironment interactions.

  4. A novel cell traction force microscopy to study multi-cellular system.

    Science.gov (United States)

    Tang, Xin; Tofangchi, Alireza; Anand, Sandeep V; Saif, Taher A

    2014-06-01

    Traction forces exerted by adherent cells on their microenvironment can mediate many critical cellular functions. Accurate quantification of these forces is essential for mechanistic understanding of mechanotransduction. However, most existing methods of quantifying cellular forces are limited to single cells in isolation, whereas most physiological processes are inherently multi-cellular in nature where cell-cell and cell-microenvironment interactions determine the emergent properties of cell clusters. In the present study, a robust finite-element-method-based cell traction force microscopy technique is developed to estimate the traction forces produced by multiple isolated cells as well as cell clusters on soft substrates. The method accounts for the finite thickness of the substrate. Hence, cell cluster size can be larger than substrate thickness. The method allows computing the traction field from the substrate displacements within the cells' and clusters' boundaries. The displacement data outside these boundaries are not necessary. The utility of the method is demonstrated by computing the traction generated by multiple monkey kidney fibroblasts (MKF) and human colon cancerous (HCT-8) cells in close proximity, as well as by large clusters. It is found that cells act as individual contractile groups within clusters for generating traction. There may be multiple of such groups in the cluster, or the entire cluster may behave a single group. Individual cells do not form dipoles, but serve as a conduit of force (transmission lines) over long distances in the cluster. The cell-cell force can be either tensile or compressive depending on the cell-microenvironment interactions.

  5. Delivering an A.S. Engineering Degree Program through Home Study Distance Education.

    Science.gov (United States)

    Sener, John

    Northern Virginia Community College (NVCC) and the Extended Learning Institute (ELI) undertook a project to develop the mathematics, science, and engineering courses required to complete an entire Associate of Science degree in Engineering through home study distance education. The project's ultimate goal was to create asynchronous learning…

  6. Traction Stresses and Translational Distortion of the Nucleus During Fibroblast Migration on a Physiologically Relevant ECM Mimic

    Science.gov (United States)

    Pan, Zhi; Ghosh, Kaustabh; Liu, Yajie; Clark, Richard A.F.; Rafailovich, Miriam H.

    2009-01-01

    Cellular traction forces, resulting in cell-substrate physical interactions, are generated by actin-myosin complexes and transmitted to the extracellular matrix through focal adhesions. These processes are highly dynamic under physiological conditions and modulate cell migration. To better understand the precise dynamics of cell migration, we measured the spatiotemporal redistribution of cellular traction stresses (force per area) during fibroblast migration at a submicron level and correlated it with nuclear translocation, an indicator of cell migration, on a physiologically relevant extracellular matrix mimic. We found that nuclear translocation occurred in pulses whose magnitude was larger on the low ligand density surfaces than on the high ligand density surfaces. Large nuclear translocations only occurred on low ligand density surfaces when the rear traction stresses completely relocated to a posterior nuclear location, whereas such relocation took much longer time on high ligand density surfaces, probably due to the greater magnitude of traction stresses. Nuclear distortion was also observed as the traction stresses redistributed. Our results suggest that the reinforcement of the traction stresses around the nucleus as well as the relaxation of nuclear deformation are critical steps during fibroblast migration, serving as a speed regulator, which must be considered in any dynamic molecular reconstruction model of tissue cell migration. A traction gradient foreshortening model was proposed to explain how the relocation of rear traction stresses leads to pulsed fibroblast migration. PMID:19450499

  7. Traction injury of the brachial plexus confused with nerve injury due to interscalene brachial block: A case report

    Directory of Open Access Journals (Sweden)

    Francisco Ferrero-Manzanal

    2016-01-01

    Conclusion: When postoperative brachial plexus palsy appears, nerve block is a confusing factor that tends to be attributed as the cause of palsy by the orthopedic surgeon. The beach chair position may predispose brachial plexus traction injury. The head and neck position should be regularly checked during long procedures, as intraoperative maneuvers may cause eventual traction of the brachial plexus.

  8. Simulating Quantitative Cellular Responses Using Asynchronous Threshold Boolean Network Ensembles

    Directory of Open Access Journals (Sweden)

    Shah Imran

    2011-07-01

    Full Text Available Abstract Background With increasing knowledge about the potential mechanisms underlying cellular functions, it is becoming feasible to predict the response of biological systems to genetic and environmental perturbations. Due to the lack of homogeneity in living tissues it is difficult to estimate the physiological effect of chemicals, including potential toxicity. Here we investigate a biologically motivated model for estimating tissue level responses by aggregating the behavior of a cell population. We assume that the molecular state of individual cells is independently governed by discrete non-deterministic signaling mechanisms. This results in noisy but highly reproducible aggregate level responses that are consistent with experimental data. Results We developed an asynchronous threshold Boolean network simulation algorithm to model signal transduction in a single cell, and then used an ensemble of these models to estimate the aggregate response across a cell population. Using published data, we derived a putative crosstalk network involving growth factors and cytokines - i.e., Epidermal Growth Factor, Insulin, Insulin like Growth Factor Type 1, and Tumor Necrosis Factor α - to describe early signaling events in cell proliferation signal transduction. Reproducibility of the modeling technique across ensembles of Boolean networks representing cell populations is investigated. Furthermore, we compare our simulation results to experimental observations of hepatocytes reported in the literature. Conclusion A systematic analysis of the results following differential stimulation of this model by growth factors and cytokines suggests that: (a using Boolean network ensembles with asynchronous updating provides biologically plausible noisy individual cellular responses with reproducible mean behavior for large cell populations, and (b with sufficient data our model can estimate the response to different concentrations of extracellular ligands. Our

  9. Traction concept of the Regio CITADIS diesel hybrid tram; Antriebskonzept der Dieselhybrid-Tram Regio CITADIS

    Energy Technology Data Exchange (ETDEWEB)

    Schroeter, H.; Soeffker, C.; Schrank, S. [ALSTOM LHB GmbH, Salzgitter (Germany)

    2007-07-01

    A regional tram with diesel hybrid traction developed for standard-gauge service for the first time in the world makes it possible for the operator to connect the inner-city tramway network with non-electrified lines in the surroundings. The modular traction system of the Regio CITADIS greatly contributes to the success of this concept. Among the features to be particularly mentioned are the intelligent control system, on the one hand, and the potential innovative extension stages, on the other. (orig.)

  10. [Lengthening of residual digit by gradual traction and bone grafting (a report of 143 cases)].

    Science.gov (United States)

    Hou, C L

    1992-06-01

    Since 1985, a device for gradual traction was used for lengthening of 143 residual digits in 75 patients. The average lengthening was 2.2 cm. This method is simple, safe, and effective. The advantages of this method over the previously exercised tubed bone graft and other digital lengthening methods are that the digit reconstructed by the gradual traction-lengthening method has the normal cutaneous structure, good sensation function, and better contour. Multiple digits can be reconstructed simultaneously. Because the periosteum at the osteotomy site is kept intact, the long term results are consistent.

  11. Analysis of electromyographic activities of the lumbar erector spinae caused by inversion traction

    OpenAIRE

    Kim, Chung Yoo; Kang, Jong Ho

    2016-01-01

    [Purpose] The purpose of this study was to analyze changes in the electromyographic activities of the lumbar erector spinae caused by inversion traction in order to verify the relaxation effect. [Subjects and Methods] The subjects included 60 healthy male adults who were equally and randomly assigned to a 30–30° group, a 30–60° group, and a 60–60° group. Inversion traction was performed for six minutes, and the electromyographic activities of the lumbar erector spinae (L2, L4) were measured b...

  12. Effect of combining traction and vibration on back muscles, heart rate and blood pressure.

    Science.gov (United States)

    Wang, Lizhen; Zhao, Meiya; Ma, Jian; Tian, Shan; Xiang, Pin; Yao, Wei; Fan, Yubo

    2014-11-01

    Eighty-five percent of the population has experienced low back pain (LBP), which may result in decreasing muscle strength and endurance, functional capacity of the spine, and so on. Traction and vibration are commonly used to relieve the low back pain. The effect of the combing traction and vibration on back muscles, heart rate (HR) and blood pressure (BP) was investigated in this study. Thirty healthy subjects participated in 12 trials lying supine on the spine-combing bed with different tilt angle (0°, 10°, 20° and 30°) and vibration modes (along with the sagittal and coronal axis with 0 Hz, 2 Hz and 12 Hz separately). EMG was recorded during each trial. Power spectral frequency analysis was applied to evaluate muscle fatigue by the shift of median power frequency (MPF). Pulse pressure (PP) was calculated from BP. HR and PP were used to estimate the effect of the combination of traction and vibration on the cardio-vascular system. It was shown that vibration could increase HR and decrease PP. The combination of traction and vibration (2 Hz vibration along Z-axis and 12 Hz vibration along Y-axis) had no significant effect on the cardio-vascular system. The MPF of lumbar erector spinae (LES) and upper trapezius (UT) decreased significantly when the angle reached 20° under the condition of 2 Hz vibration along Z-axis compared with it of 0°. Furthermore, the MPF also decreased significantly compared with it of static mode at 20° for LES and at 30° for UT. However at 12 Hz vibration along Y-axis, the MPF had significant increase when the angle reached 20° in LES and 30° in UT compared to 0°. For LES, the MPF also had significant difference when the angle was increased from 10° to 20°. Therefore, combining 2 Hz vibration along Z-axis and traction (tilt angles that less than 20°) may to reduce muscle fatigue both for LES and UT compared with either vibration or traction alone. The combination of 12 Hz vibration along Y-axis and traction (tilt angles

  13. Coordination of Flow and Traction in Migration of Amoeboid Physarum polycephalum: Model and Measurement

    Science.gov (United States)

    Lewis, Owen; Guy, Robert; Zhang, Shun; Del Alamo, Juan Carlos

    2014-11-01

    In this research, we develop a computational model of crawling Physarum based on the Immersed Boundary Method. Our model incorporates the effects of cell cytoplasm, the internal cytoskeleton and adhesions to the substrate. Cytoplasmic flows and traction stresses predicted by the model are compared to experimentally measured values obtained using simultaneous Traction Force Microscopy (TFM) and Particle Image Velocimetry (PIV). Of particular interest are stresses generated by flow and how transmission of stresses to the substrate is coordinated. We identify methods of adhesion-flow coordination which are consistent with experiments. Certain consisten coordinations are seen to be ``optimal'' with regards to crawling speed, and robust to perturbations in the extracellular environment.

  14. Analysis and Comparison of Modular Railway Power Conditioner for High-Speed Railway Traction System

    DEFF Research Database (Denmark)

    Xu, Qianming; Ma, Fujun; He, Zhixing

    2017-01-01

    With the rapid development of modern electrified railway, negative sequence current (NSC) minimization is one of the most important considerations in the high-speed railway traction system. In the past, many multiple or multilevel topologies with high compensation capacity have been introduced...... for railway power conditioner (RPC). This paper presents a simplified quantitative comparison of five previous modular RPC topologies for negative sequence compensation in V/V and SCOTT traction systems, aiming for an optimal selection of the compensators. Performance criteria such as transformer requirement...

  15. CRITERES DE RUPTURE DE MATERIAUX FRAGILES INTEGRANT LA DISSYMETRIE EN TRACTION ET COMPRESSION

    Directory of Open Access Journals (Sweden)

    G PLUVINAGE

    2003-06-01

    Full Text Available Nous proposons une approche générale des critères de résistance à la rupture pour des matériaux présentant une dissymétrie de comportement en traction et compression. Elle est basée sur l’égalité des énergies de rupture en traction et compression et repose sur le concept d’endommagement associé à un formalisme énergétique.

  16. Photonic analog-to-digital converter via asynchronous oversampling

    Science.gov (United States)

    Carver, Spencer; Reeves, Erin; Siahmakoun, Azad; Granieri, Sergio

    2012-06-01

    This paper presents a hybrid opto-electronic asynchronous delta-sigma modulator, implemented in the form of a fiber-optic Analog-to-Digital converter (ADC). This architecture was chosen for its independence of an external clock and ease of demodulation through a single low-pass filter stage. The fiber-optic prototype consists of an input laser (wavelength λ1) which is modulated with an input RF signal, a high-speed comparator circuit working as bi-stable quantizer, and a fiber-optic loop that includes a SOA and a band-pass filter that act as a leaky integrator. The fiber-optic loop acts as a fiber-ring resonator (FRR), and defines the resonance wavelength λ2 of the system. The gain within this loop is modified through cross-gain modulation (XGM) by the input wavelength λ1, and thus achieves the desired modulation effect. The proposed architecture has been constructed and characterized at a sampling rate of 15.4 MS/s processing input analog signals in the range of dc-3 MHz with a signal-to-noise ratio of 36 dB and an effective number of bits of 5.7.

  17. Normalized and asynchronous mirror alignment for Cherenkov telescopes

    Science.gov (United States)

    Ahnen, M. L.; Baack, D.; Balbo, M.; Bergmann, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K. A.; Buss, J.; Domke, M.; Dorner, D.; Einecke, S.; Hempfling, C.; Hildebrand, D.; Hughes, G.; Lustermann, W.; Mannheim, K.; Mueller, S. A.; Neise, D.; Neronov, A.; Noethe, M.; Overkemping, A.-K.; Paravac, A.; Pauss, F.; Rhode, W.; Shukla, A.; Temme, F.; Thaele, J.; Toscano, S.; Vogler, P.; Walter, R.; Wilbert, A.

    2016-09-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it can reconstruct all individual mirror facet point spread functions without moving any mirror. We present alignment results on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

  18. [System of telesonography with synchronous teleconsultations and asynchronous telediagnoses (Togo)].

    Science.gov (United States)

    Adambounou, K; Farin, F; Boucher, A; Adjenou, K V; Gbeassor, M; N'dakena, K; Vincent, N; Arbeille, P

    2012-01-01

    Ultrasonography is an important nonirradiating diagnostic medical imaging procedure, frequently used, especially in urgent circumstances. This relatively inexpensive noninvasive examination makes it possible to diagnose disorders in various parts of the human body, by examining, for example, the abdomen and pelvis, the cardiovascular system, and the muscles and joints. Ultrasound is also an operator-dependent examination, in that the quality of the result depends on precision in the manipulation of the probe. Unfortunately, many small medical centers and isolated sites do not have an appropriate well-trained sonographer to perform initial evaluations, and an untrained operator cannot capture the appropriate echographic views required for a safe diagnosis of current patients, even with realtime vocal guidance (personal data). The lack of experienced physicians or qualified technicians means that diagnostic ultrasound is not always accessible to patients for rapid examination worldwide, especially in Africa, Amazonia or near the North or South Poles. This situation has led to the development of a new concept of telemedicine: telesonography, with a remote ultrasound diagnosis either in real time (synchronous) or delayed (asynchronous; store-and-forward). These systems of real-time telesonography and data transmission require expensive and complex technology with sophisticated equipment not available in many developing countries. The purpose of this study is to design a low-cost real-time system of telesonography for teleconsultations with experts and a delayed telediagnostic mode between isolated peripheral hospitals and a University Hospital center (UHC). An IP camera and an internet video server were installed in a geographically isolated site equipped with an ultrasound machine and an operator with basic training in its use. Synchronous teleconsultation (second-opinion diagnosis) is possible via internet with a UHC expert. If no ultrasound operator is available at

  19. Stabilization of parameters of asynchronous electric drive with vector control

    Directory of Open Access Journals (Sweden)

    N.J. Khlopenko

    2015-03-01

    Full Text Available A problem of stabilization of parameters of the asynchronous electric drive vector control system is considered. Usually such systems have two control channels. The synthesis of stabilizing controllers is made for every control channel. The evaluation of variables of system status is made by observer. The problem of stabilizing controllers and observer synthesis consists in calculation of state feedback intensification. Its solution is based on existing approaches form vector control theories, matrix inequalities and Lyapunov stability. Several synthesis methods of stabilizing controllers have been proposed. Structural scheme of vector control system and observer has been built. The simulation of transient processes in the vector control system is carried out with MATLAB computing environment. The most important property of obtained solution is Lyapunov stability of control loops closed-looped by state vectors. Transient processes have been investigated on the particular example. Graphs confirming stability of such processes that flow in the vector control system in minimal period of time have been plotted down.

  20. Enantioseparation of racemic aminoglutethimide using asynchronous simulated moving bed chromatography.

    Science.gov (United States)

    Lin, Xiaojian; Gong, Rujin; Li, Jiaxu; Li, Ping; Yu, Jianguo; Rodrigues, Alirio E

    2016-10-07

    The separation of aminoglutethimide enantiomers by the continuous multicolumn chromatographic processes were investigated experimentally and theoretically, where the columns were packed with cellulose tris 3,5-dimethylphenyl-carbamate stationary phase (brand name Chiralcel OD) and mobile phase was a mixture of n-hexane and ethanol with monoethanolamine additive. The continuous enantioseparation processes included a synchronous shifting process (SMB) and an asynchronous shifting process (VARICOL), which allowed reducing the column number (here from six-column SMB to five-column VARICOL process). Transport-dispersive model with the consideration of both intraparticle mass transfer resistance and axial dispersion was adopted to design and optimize the operation conditions for the separation of aminoglutethimide enantiomers by SMB process and VARICOL process. According to the optimized operation conditions, experiments were carried out on VARICOL-Micro unit using five-column VARICOL process with 1/1.5/1.5/1 configuration and six-column SMB process with 1/2/2/1 configuration. Products of R-aminoglutethimide (R-AG) enantiomer and S-aminoglutethimide (S-AG) enantiomer with more than 99.0% purity were obtained continuously from extract stream and raffinate stream, respectively. Furthermore, the experiemntal data obtained from five-column VARICOL process were compared with that from six-column SMB process, the feasibility and efficiency for the separation of guaifenesin enantiomers by VARICOL processes were evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.