WorldWideScience

Sample records for switching locomotives

  1. Locomotion

    DEFF Research Database (Denmark)

    Kiehn, Ole; Dougherty, Kimberly

    2016-01-01

    Locomotion is a complex motor behavior needed by animals and humans to move through the environment. All forms of locomotion, including swimming, flying, walking, running, and hopping, are repetitive motor activities that require the activation of the limb and body muscles in an organized rhythm ...

  2. 49 CFR 231.16 - Steam locomotives used in switching service.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotives used in switching service. 231... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.16 Steam..., buffer block, footboard, brake pipe, signal pipe, steam-heat pipe or arms of uncoupling lever shall...

  3. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches... SERVICE FOR RAILROADS 1 Operating Expenses-Transportation § 1242.67 Switch crews; controlling operations...

  4. Consequences of life history switch point plasticity for juvenile morphology and locomotion in the Túngara frog

    Directory of Open Access Journals (Sweden)

    Julie F. Charbonnier

    2015-09-01

    Full Text Available Many animals with complex life cycles can cope with environmental uncertainty by altering the timing of life history switch points through plasticity. Pond hydroperiod has important consequences for the fitness of aquatic organisms and many taxa alter the timing of life history switch points in response to habitat desiccation. For example, larval amphibians can metamorphose early to escape drying ponds. Such plasticity may induce variation in size and morphology of juveniles which can result in carry-over effects on jumping performance. To investigate the carry-over effects of metamorphic plasticity to pond drying, we studied the Túngara frog, Physalaemus pustulosus, a tropical anuran that breeds in highly ephemeral habitats. We conducted an outdoor field mesocosm experiment in which we manipulated water depth and desiccation and measured time and size at metamorphosis, tibiofibula length and jumping performance. We also conducted a complimentary laboratory experiment in which we manipulated resources, water depth and desiccation. In the field experiment, metamorphs from dry-down treatments emerged earlier, but at a similar size to metamorphs from constant depth treatments. In the laboratory experiment, metamorphs from the low depth and dry-down treatments emerged earlier and smaller. In both experiments, frogs from dry-down treatments had relatively shorter legs, which negatively impacted their absolute jumping performance. In contrast, reductions in resources delayed and reduced size at metamorphosis, but had no negative effect on jumping performance. To place these results in a broader context, we review past studies on carry-over effects of the larval environment on jumping performance. Reductions in mass and limb length generally resulted in lower jumping performance across juvenile anurans tested to date. Understanding the consequences of plasticity on size, morphology and performance can elucidate the linkages between life stages.

  5. Hybrid Locomotive for Energy Savings and Reduced Emissions

    Science.gov (United States)

    2017-08-01

    Norfolk Southern Corporation (NS) and Pennsylvania State University tested several different battery systems in hybrid locomotives. Advanced lithium-ion battery technology was the only kind that displayed the capacity to perform in heavy switching or...

  6. Locomotion through Morphosis

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian

    , this is still not the case. One of the reasons for this is that science does still not fully understand the principles of dynamic locomotion which is a requirement for them to move around in our environment with stairs, obstacles etc. In this thesis the focus will be on the creation of the modular robotic...... it have been build. This will hopefully help to identify which parameters that are affecting the locomotive abilities of a legged robot the most. Experiments shows that the system in its current state is able for form legged robots of various kinds, and perform walking gaits where phenomenon’s also seen...

  7. Development of human locomotion.

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka

    2012-10-01

    Neural control of locomotion in human adults involves the generation of a small set of basic patterned commands directed to the leg muscles. The commands are generated sequentially in time during each step by neural networks located in the spinal cord, called Central Pattern Generators. This review outlines recent advances in understanding how motor commands are expressed at different stages of human development. Similar commands are found in several other vertebrates, indicating that locomotion development follows common principles of organization of the control networks. Movements show a high degree of flexibility at all stages of development, which is instrumental for learning and exploration of variable interactions with the environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Dynamically Stable Legged Locomotion

    Science.gov (United States)

    1989-09-01

    length during overground locomotion: task-specific modulation of the locomotor synergy. Journal of Experimental Psychology, 15(3). Raibert, M. I. 1986...energy conversions that intermediates between combus- tion of a fluid fuel such as gasoline , and the controlled delivery of force and power to the...question of this study: Can the extremely high energy density and rapid response of combustible fluid fuels such as gasoline be harnessed to produce

  9. Advanced robot locomotion.

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry; Feddema, John Todd; Spletzer, Barry Louis; Rose, Scott E.; Novick, David Keith; Wilson, David Gerald; Buerger, Stephen P.

    2007-01-01

    This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics natural human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.

  10. Locomotive energy savings possibilities

    Directory of Open Access Journals (Sweden)

    Leonas Povilas LINGAITIS

    2009-01-01

    Full Text Available Economic indicators of electrodynamic braking have not been properly estimated. Vehicles with alternative power trains are transitional stage between development of pollution- free vehicles. According to these aspects the investigation on conventional hybrids drives and their control system is carried out in the article. The equation that allows evaluating effectiveness of regenerative braking for different variants of hybrid drive are given. Presenting different types of locomotive energy savings power systems, which are using regenerative braking energy any form of hybrid traction vehicles systems, circuit diagrams, electrical parameters curves.

  11. Steam Locomotives: a forgotten era

    African Journals Online (AJOL)

    The boiler was not armoured as the idea was that it was bullet proof. The locomotives were arranged into groups of five and for each group there was an engine as standby. As far as can be ascertained, locomotive No 537 was never armoured, but did work draw trains and freight trains during the Anglo-Boer War too.

  12. Synthesis of digital locomotive receiver of automatic locomotive signaling

    Directory of Open Access Journals (Sweden)

    K. V. Goncharov

    2013-02-01

    Full Text Available Purpose. Automatic locomotive signaling of continuous type with a numeric coding (ALSN has several disadvantages: a small number of signal indications, low noise stability, high inertia and low functional flexibility. Search for new and more advanced methods of signal processing for automatic locomotive signaling, synthesis of the noise proof digital locomotive receiver are essential. Methodology. The proposed algorithm of detection and identification locomotive signaling codes is based on the definition of mutual correlations of received oscillation and reference signals. For selecting threshold levels of decision element the following criterion has been formulated: the locomotive receiver should maximum set the correct solution for a given probability of dangerous errors. Findings. It has been found that the random nature of the ALSN signal amplitude does not affect the detection algorithm. However, the distribution law and numeric characteristics of signal amplitude affect the probability of errors, and should be considered when selecting a threshold levels According to obtained algorithm of detection and identification ALSN signals the digital locomotive receiver has been synthesized. It contains band pass filter, peak limiter, normalizing amplifier with automatic gain control circuit, analog to digital converter and digital signal processor. Originality. The ALSN system is improved by the way of the transfer of technical means to modern microelectronic element base, more perfect methods of detection and identification codes of locomotive signaling are applied. Practical value. Use of digital technology in the construction of the locomotive receiver ALSN will expand its functionality, will increase the noise immunity and operation stability of the locomotive signal system in conditions of various destabilizing factors.

  13. Artificial locomotion control

    DEFF Research Database (Denmark)

    Azevedo, Christine; Poignet, Philippe; Espiau, Bernard

    2004-01-01

    of postural and walking control; use of evolutive optimization objectives; on-line event handling and environment adaptation and anticipation. This leads to the synthesis of an original control scheme based on non-linear model predictive control: Trajectory Free NMPC. The movement is specified implicitly......This paper concerns the simultaneous synthesis and control of walking gaits for biped robots. The goal is to propose an adaptable and reactive control law for two-legged machines. The problem is addressed with human locomotion as a reference. The starting point of our work is an analysis of human...... walking from descriptive (biomechanics) as well as explicative (neuroscience and physiology) points of view, the objective being to stress the relevant elements for the approach of robot control. The adopted principles are then: no joint trajectory tracking; explicit distinction and integration...

  14. AN ANALYTICAL STUDY OF SWITCHING TRACTION MOTORS

    Directory of Open Access Journals (Sweden)

    V. M. Bezruchenko

    2010-03-01

    Full Text Available The analytical study of switching of the tractive engines of electric locomotives is conducted. It is found that the obtained curves of change of current of the sections commuted correspond to the theory of average rectilinear switching. By means of the proposed method it is possible on the stage of design of tractive engines to forecast the quality of switching and to correct it timely.

  15. Animal Locomotion in Different Mediums

    Indian Academy of Sciences (India)

    IAS Admin

    examine only self-powered animal locomotion. ... At different phases of their life cycle both animals and plants are highly mobile but their ... wind driven transport (Figure C). ..... fins which serve the function of rudimentary limbs, particularly.

  16. Locomotion of bluefish.

    Science.gov (United States)

    DuBois, A B; Cavagna, G A; Fox, R S

    1976-02-01

    1. Pressure previously measured on the body surface of swimming bluefish were resolved into their backward vectorial components to allow calculation of profile drag. It was 0.18 kg at a speed of 1.8 m/sec. Tangential drag was calculated as if for a thin plate of an area equal to that of the fish. It was 0.08 kg at 1.8 m/sec. Net drag, 0.26 kg, was the sum of profile and tangential drag. 2. Thrust and drag also were calculated from the changes of acceleration measured during steady swimming, assuming that thrust took place only during the acceleration phase, whereas drag occurred during both acceleration and deceleration. This drag was 0.08 kg at a speed of 1.1 m/sec. It is compatible with the drag of 0.26 at 1.8 m/sec calculated from profile and tangential drag provided drag varies as the square of velocity. 3. The force required to produced maximal acceleration was measured during a scare. It was calculated to be 6.9 kg at a peak acceleration of 3 g. 4. The compression strength of th vertebrae was found to be approximately 20 kg per cm2, or roughly three times the force encountered during maximal acceleration. This safety factor of 3 would be reduced when the back was curved, or if opposing groups of muscles were under tension. 5. The finding that a bluefish can accelerate at 3 g and that the vertebral column is strongg enough to withstand this force indicates that the muscles and body structure of a bluefish would be able to withstand the force of gravity if the fish were otherwise equipped for terrestrial life. This fish may have evolved these strengths simultaneously with land animals. It is speculated that other fish may have evolved some degree of strength to overcome inertia and drag during aquatic locomotion, and this evolution may have been a prelude to terrestrial locomotion.

  17. Fundamentals of soft robot locomotion

    OpenAIRE

    Calisti, M.; Picardi, G.; Laschi, C.

    2017-01-01

    Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human���robot interaction and locomotion. Although field applications have emerged for soft manipulation and human���robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This p...

  18. Small-scale soft-bodied robot with multimodal locomotion

    Science.gov (United States)

    Hu, Wenqi; Lum, Guo Zhan; Mastrangeli, Massimo; Sitti, Metin

    2018-02-01

    Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly, in bioengineering such as single-cell manipulation and biosensing, and in healthcare such as targeted drug delivery and minimally invasive surgery. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.

  19. Fundamentals of soft robot locomotion.

    Science.gov (United States)

    Calisti, M; Picardi, G; Laschi, C

    2017-05-01

    Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human-robot interaction and locomotion. Although field applications have emerged for soft manipulation and human-robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This paper aims to provide a reference guide for researchers approaching mobile soft robotics, to describe the underlying principles of soft robot locomotion with its pros and cons, and to envisage applications and further developments for mobile soft robotics. © 2017 The Author(s).

  20. The mechanics of slithering locomotion.

    Science.gov (United States)

    Hu, David L; Nirody, Jasmine; Scott, Terri; Shelley, Michael J

    2009-06-23

    In this experimental and theoretical study, we investigate the slithering of snakes on flat surfaces. Previous studies of slithering have rested on the assumption that snakes slither by pushing laterally against rocks and branches. In this study, we develop a theoretical model for slithering locomotion by observing snake motion kinematics and experimentally measuring the friction coefficients of snakeskin. Our predictions of body speed show good agreement with observations, demonstrating that snake propulsion on flat ground, and possibly in general, relies critically on the frictional anisotropy of their scales. We have also highlighted the importance of weight distribution in lateral undulation, previously difficult to visualize and hence assumed uniform. The ability to redistribute weight, clearly of importance when appendages are airborne in limbed locomotion, has a much broader generality, as shown by its role in improving limbless locomotion.

  1. Relation between observed locomotion traits and locomotion score in dairy cows

    NARCIS (Netherlands)

    Schlageter Tello, A.A.; Bokkers, E.A.M.; Groot Koerkamp, P.W.G.; Hertem, van T.; Viazzi, S.; Lokhorst, Kees

    2015-01-01

    Lameness is still an important problem in modern dairy farming. Human observation of locomotion, by looking at different traits in one go, is used in practice to assess locomotion. The objectives of this article were to determine which individual locomotion traits are most related to locomotion

  2. In Pipe Robot with Hybrid Locomotion System

    Directory of Open Access Journals (Sweden)

    Cristian Miclauş

    2015-06-01

    Full Text Available The first part of the paper covers aspects concerning in pipe robots and their components, such as hybrid locomotion systems and the adapting mechanisms used. The second part describes the inspection robot that was developed, which combines tracked and wheeled locomotion (hybrid locomotion. The end of the paper presents the advantages and disadvantages of the proposed robot.

  3. Locomotive monitoring system using wireless sensor networks

    CSIR Research Space (South Africa)

    Croucamp, PL

    2014-07-01

    Full Text Available Theft of cables used for powering a locomotive not only stops the train from functioning but also paralyzes the signalling and monitoring system. This means that information on certain locomotive's cannot be passed onto other locomotives which may...

  4. Locomotion of Mexican jumping beans

    International Nuclear Information System (INIS)

    West, Daniel M; K Lal, Ishan; Leamy, Michael J; Hu, David L

    2012-01-01

    The Mexican jumping bean, Laspeyresia saltitans, consists of a hollow seed housing a moth larva. Heating by the sun induces movements by the larva which appear as rolls, jumps and flips by the bean. In this combined experimental, numerical and robotic study, we investigate this unique means of rolling locomotion. Time-lapse videography is used to record bean trajectories across a series of terrain types, including one-dimensional channels and planar surfaces of varying inclination. We find that the shell encumbers the larva's locomotion, decreasing its speed on flat surfaces by threefold. We also observe that the two-dimensional search algorithm of the bean resembles the run-and-tumble search of bacteria. We test this search algorithm using both an agent-based simulation and a wheeled Scribbler robot. The algorithm succeeds in propelling the robot away from regions of high temperature and may have application in biomimetic micro-scale navigation systems. (paper)

  5. Emotion through Locomotion: Gender Impact

    OpenAIRE

    Kr?ger, Samuel; Sokolov, Alexander N.; Enck, Paul; Kr?geloh-Mann, Ingeborg; Pavlova, Marina A.

    2013-01-01

    Body language reading is of significance for daily life social cognition and successful social interaction, and constitutes a core component of social competence. Yet it is unclear whether our ability for body language reading is gender specific. In the present work, female and male observers had to visually recognize emotions through point-light human locomotion performed by female and male actors with different emotional expressions. For subtle emotional expressions only, males surpass fema...

  6. Emotion through locomotion: gender impact.

    Directory of Open Access Journals (Sweden)

    Samuel Krüger

    Full Text Available Body language reading is of significance for daily life social cognition and successful social interaction, and constitutes a core component of social competence. Yet it is unclear whether our ability for body language reading is gender specific. In the present work, female and male observers had to visually recognize emotions through point-light human locomotion performed by female and male actors with different emotional expressions. For subtle emotional expressions only, males surpass females in recognition accuracy and readiness to respond to happy walking portrayed by female actors, whereas females exhibit a tendency to be better in recognition of hostile angry locomotion expressed by male actors. In contrast to widespread beliefs about female superiority in social cognition, the findings suggest that gender effects in recognition of emotions from human locomotion are modulated by emotional content of actions and opposite actor gender. In a nutshell, the study makes a further step in elucidation of gender impact on body language reading and on neurodevelopmental and psychiatric deficits in visual social cognition.

  7. The noise factor in railway locomotives.

    Science.gov (United States)

    Rotter, T

    1982-09-01

    This article concerns the problem of acoustic work conditions on railway locomotives. The objective results of sonometric surveys in locomotive cabins are compared with subject data received from locomotive crews obtained by means of a specific questionnaire 'The Subjective Estimation of Noise'. The analysis touched 9 type of locomotives; steam, diesel and electric engines. We asked drivers of different age groups and with varying lengths of professional service for their opinions The aim of the investigation was to determine the following points: 1. to analyse the drivers' subjective estimation of the noise in the locomotive cabins; 2. to define length of time for which the driver remains under the influence of the noise after finishing work; 3. to investigate the question of perception and understanding of sounds and vocal signals used in the locomotive. These problems are a small part of the general plan to improve work conditions on the Polish National Railways.

  8. Railroad and locomotive technology roadmap.

    Energy Technology Data Exchange (ETDEWEB)

    Stodolsky, F.; Gaines, L.; Energy Systems

    2003-02-24

    Railroads are important to the U.S. economy. They transport freight efficiently, requiring less energy and emitting fewer pollutants than other modes of surface transportation. While the railroad industry has steadily improved its fuel efficiency--by 16% over the last decade--more can, and needs to, be done. The ability of locomotive manufacturers to conduct research into fuel efficiency and emissions reduction is limited by the small number of locomotives manufactured annually. Each year for the last five years, the two North American locomotive manufacturers--General Electric Transportation Systems and the Electro-Motive Division of General Motors--have together sold about 800 locomotives in the United States. With such a small number of units over which research costs can be spread, outside help is needed to investigate all possible ways to reduce fuel usage and emissions. Because fuel costs represent a significant portion of the total operating costs of a railroad, fuel efficiency has always been an important factor in the design of locomotives and in the operations of a railroad. However, fuel efficiency has recently become even more critical with the introduction of strict emission standards by the U.S. Environmental Protection Agency, to be implemented in stages (Tiers 0, 1, and 2) between 2000 and 2005. Some of the technologies that could be employed to meet the emission standards may negatively affect fuel economy--by as much as 10-15% when emissions are reduced to Tier 1 levels. Lowering fuel economy by that magnitude would have a serious impact on the cost to the consumer of goods shipped by rail, on the competitiveness of the railroad industry, and on this country's dependence on foreign oil. Clearly, a joint government/industry R&D program is needed to help catalyze the development of advanced technologies that will substantially reduce locomotive engine emissions while also improving train system energy efficiency. DOE convened an industry

  9. Blunt impact tests of retired passenger locomotive fuel tanks

    Science.gov (United States)

    2017-08-01

    The Transportation Technology Center, Inc. conducted impact tests on three locomotive fuel tanks as part of the Federal Railroad Administrations locomotive fuel tank crashworthiness improvement program. Three fuel tanks, two from EMD F40PH locomot...

  10. Le Shuttle, the locomotive from Eurotunnel

    OpenAIRE

    Gabriel MOISA

    2002-01-01

    This paper present some performances of locomotive ‘Le Shuttle’, so-called locomotive from ‘Eurotunnel’, techniques characteristics of traction motors 6 FHA 7079 and converters witch use it, the principal electric scheme and its function principle and no at last rind the principle scheme of command-control equipment MICAS-S2 with detailed description of its operation mode.

  11. Locomotive Crash Energy Management Coupling Tests

    Science.gov (United States)

    2018-04-18

    This paper describes the results of the CEM equipped locomotive coupling tests. In this set of tests, a moving CEM locomotive was coupled to a standing cab car. The primary objective was to demonstrate the robustness of the PBC design and determine t...

  12. The investigation of the locomotive boiler material

    International Nuclear Information System (INIS)

    Tucholski, Z.; Wasiak, J.; Bilous, W.; Hajewska, E.

    2006-01-01

    In the paper, the history of narrow-gauge railway system is described. The other information about the steam locomotive construction, as well as the technical regulations of its construction and exploitation are also done. The results of the studies of the locomotive boiler material are presented. (authors)

  13. 77 FR 21311 - Locomotive Safety Standards

    Science.gov (United States)

    2012-04-09

    ... preparedness, alcohol and drug testing, locomotive engineer certification, and workplace safety. In 1980, FRA... Association (ATDA) Amtrak AAR Association of Railway Museums (ARM) Association of State Rail Safety Managers... Administration 49 CFR Parts 229 and 238 Locomotive Safety Standards; Final Rule #0;#0;Federal Register / Vol. 77...

  14. 76 FR 2199 - Locomotive Safety Standards

    Science.gov (United States)

    2011-01-12

    ..., alcohol and drug testing, locomotive engineer certification, and workplace safety. In 1980, FRA issued the...) Association of State Rail Safety Managers (ASRSM) Brotherhood of Locomotive Engineers and Trainmen (BLET... desirable to minimize the health and safety effects of temperature extremes. Depending upon the workplace...

  15. Exciter switch

    Science.gov (United States)

    Mcpeak, W. L.

    1975-01-01

    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  16. Continuum limbed robots for locomotion

    Science.gov (United States)

    Mutlu, Alper

    This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

  17. Unifying Rules for Aquatic Locomotion

    Science.gov (United States)

    Saadat, Mehdi; Domel, August; di Santo, Valentina; Lauder, George; Haj-Hariri, Hossein

    2016-11-01

    Strouhal number, St (=fA/U) , a scaling parameter that relates speed, U, to the tail-beat frequency, f, and tail-beat amplitude, A, has been used many times to describe animal locomotion. It has been observed that swimming animals cruise at 0.2 fish-like swimmer, we show that when cruising at minimum hydrodynamic input power, St is predetermined, and is only a function of the shape, i.e. drag coefficient and area. The narrow range for St, 0.2-0.4, has been previously associated with optimal propulsive efficiency. However, St alone is insufficient for deciding optimal motion. We show that hydrodynamic input power (energy usage to propel over a unit distance) in fish locomotion is minimized at all cruising speeds when A* (= A/L), a scaling parameter that relates tail-beat amplitude, A, to the length of the swimmer, L, is constrained to a narrow range of 0.15-0.25. Our analysis proposes a constraint on A*, in addition to the previously found constraint on St, to fully describe the optimal swimming gait for fast swimmers. A survey of kinematics for dolphin, as well as new data for trout, show that the range of St and A* for fast swimmers indeed are constrained to 0.2-0.4 and 0.15-0.25, respectively. Our findings provide physical explanation as to why fast aquatic swimmers cruise with relatively constant tail-beat amplitude at approximately 20 percent of body length, while their swimming speed is linearly correlated with their tail-beat frequency.

  18. Locomotive Assignment Problem with Heterogeneous Vehicle Fleet and Hiring External Locomotives

    Directory of Open Access Journals (Sweden)

    Dušan Teichmann

    2015-01-01

    Full Text Available This paper focuses on solving the problem of how to assign locomotives to assembled trains optimally. To solve the problem, linear programming is applied. The situation we model in the paper occurs in the conditions of a transport operator that provides rail transport in the Czech Republic. In the paper, an extended locomotive assignment problem is modeled; the transport operator can use different classes of the locomotives to serve individual connections, some connections must be served by a predefined locomotive class, and the locomotives can be allocated to several depots at the beginning. The proposed model also takes into consideration the fact that some connections can be served by the locomotives of external transport companies or operators. The presented model is applied to a real example in order to test its functionality.

  19. 49 CFR 229.121 - Locomotive cab noise.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive cab noise. 229.121 Section 229.121... § 229.121 Locomotive cab noise. (a) Performance standards for locomotives. (1) When tested for static noise in accordance with paragraph (a)(3) of this section, all locomotives of each design or model that...

  20. 49 CFR 238.223 - Locomotive fuel tanks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the requirements...

  1. Modeling limbless locomotion using ADAMS software

    Data.gov (United States)

    National Aeronautics and Space Administration — Until now, the methods used by probes or humans for locomotion on planetary surfaces have typically been restricted to variations of wheeled motion. As human...

  2. Le Shuttle, the locomotive from Eurotunnel

    Directory of Open Access Journals (Sweden)

    Gabriel MOISA

    2002-12-01

    Full Text Available This paper present some performances of locomotive ‘Le Shuttle’, so-called locomotive from ‘Eurotunnel’, techniques characteristics of traction motors 6 FHA 7079 and converters witch use it, the principal electric scheme and its function principle and no at last rind the principle scheme of command-control equipment MICAS-S2 with detailed description of its operation mode.

  3. Pseudospark switches

    International Nuclear Information System (INIS)

    Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

    1987-01-01

    The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

  4. The PS locomotive runs again

    CERN Multimedia

    2001-01-01

    Over forty years ago, the PS train entered service to steer the magnets of the accelerator into place... ... a service that was resumed last Tuesday. Left to right: Raymond Brown (CERN), Claude Tholomier (D.B.S.), Marcel Genolin (CERN), Gérard Saumade (D.B.S.), Ingo Ruehl (CERN), Olivier Carlier (D.B.S.), Patrick Poisot (D.B.S.), Christian Recour (D.B.S.). It is more than ten years since people at CERN heard the rumbling of the old PS train's steel wheels. Last Tuesday, the locomotive came back into service to be tested. It is nothing like the monstrous steel engines still running on conventional railways -just a small electric battery-driven vehicle employed on installing the magnets for the PS accelerator more than 40 years ago. To do so, it used the tracks that run round the accelerator. In fact, it is the grandfather of the LEP monorail. After PS was commissioned in 1959, the little train was used more and more rarely. This is because magnets never break down, or hardly ever! In fact, the loc...

  5. Patterned control of human locomotion

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka

    2012-01-01

    There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost. PMID:22411012

  6. Patterned control of human locomotion.

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka

    2012-05-15

    There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost.

  7. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Science.gov (United States)

    2010-07-01

    ... the nonconformity of any such locomotives or locomotive engines which have been, if required by the... affected by the remedy and a general statement of the measures to be taken to correct the nonconformity. (5) A description of the adverse effects, if any, that an uncorrected nonconformity would have on the...

  8. Locomotive fuel tank structural safety testing program : passenger locomotive fuel tank jackknife derailment load test.

    Science.gov (United States)

    2010-08-01

    This report presents the results of a passenger locomotive fuel tank load test simulating jackknife derailment (JD) load. The test is based on FRA requirements for locomotive fuel tanks in the Title 49, Code of Federal Regulations (CFR), Part 238, Ap...

  9. The Role of Adaptation in Body Load-Regulating Mechanisms During Locomotion

    Science.gov (United States)

    Ruttley, Tara; Holt, Christopher; Mulavara, Ajitkumar; Bloomberg, Jacob

    2010-01-01

    Body loading is a fundamental parameter that modulates motor output during locomotion, and is especially important for controlling the generation of stepping patterns, dynamic balance, and termination of locomotion. Load receptors that regulate and control posture and stance in locomotion include the Golgi tendon organs and muscle spindles at the hip, knee, and ankle joints, and the Ruffini endings and the Pacinian corpuscles in the soles of the feet. Increased body weight support (BWS) during locomotion results in an immediate reorganization of locomotor control, such as a reduction in stance and double support duration and decreased hip, ankle, and knee angles during the gait cycle. Previous studies on the effect during exposure to increased BWS while walking showed a reduction in lower limb joint angles and gait cycle timing that represents a reorganization of locomotor control. Until now, no studies have investigated how locomotor control responds after a period of exposure to adaptive modification in the body load sensing system. The goal of this research was to determine the adaptive properties of body load-regulating mechanisms in locomotor control during locomotion. We hypothesized that body load-regulating mechanisms contribute to locomotor control, and adaptive changes in these load-regulating mechanisms require reorganization to maintain forward locomotion. Head-torso coordination, lower limb movement patterns, and gait cycle timing were evaluated before and after a 30-minute adaptation session during which subjects walked on a treadmill at 5.4 km/hr with 40% body weight support (BWS). Before and after the adaptation period, head-torso and lower limb 3D kinematic data were obtained while performing a goal directed task during locomotion with 0% BWS using a video-based motion analysis system, and gait cycle timing parameters were collected by foot switches positioned under the heel and toe of the subjects shoes. Subjects showed adaptive modification in

  10. The Human Central Pattern Generator for Locomotion.

    Science.gov (United States)

    Minassian, Karen; Hofstoetter, Ursula S; Dzeladini, Florin; Guertin, Pierre A; Ijspeert, Auke

    2017-03-01

    The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.

  11. Passive appendages aid locomotion through symmetry breaking

    Science.gov (United States)

    Bagheri, Shervin; Lacis, Ugis; Mazzino, Andrea; Kellay, Hamid; Brosse, Nicolas; Lundell, Fredrik; Ingremeau, Francois

    2014-11-01

    Plants and animals use plumes, barbs, tails, feathers, hairs, fins, and other types of appendages to aid locomotion. Despite their enormous variation, passive appendages may contribute to locomotion by exploiting the same physical mechanism. We present a new mechanism that applies to body appendages surrounded by a separated flow, which often develops behind moving bodies larger than a few millimeters. We use theory, experiments, and numerical simulations to show that bodies with protrusions turn and drift by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in flowing fluid is unstable and how it stabilizes either to the left or right of the incoming fluid flow direction. The discovery suggests a new mechanism of locomotion that may be relevant for certain organisms; for example, how plumed seeds may drift without wind and how motile animals may passively reorient themselves.

  12. Operating a locomotive on liquid methane fuel

    International Nuclear Information System (INIS)

    Stolz, J.L.

    1992-01-01

    This paper reports that several years ago, Burlington Northern Railroad looked into the feasibility of operating a diesel railroad locomotive to also run on compressed natural gas in a dual-fuel mode. Recognizing the large volume of on-board storage required and other limitations of CNG in the application, a program was begun to fuel a locomotive with liquefied natural gas. Because natural gas composition can vary with source and processing, it was considered desirable to use essentially pure liquid methane as the engine fuel. Initial testing results show the locomotive system achieved full diesel-rated power when operating on liquid methane and with equivalent fuel efficiency. Extended testing, including an American Association of Railroad 500-hour durability test, was undertaken to obtain information on engine life, wear rate and lubrication oil life

  13. Numerical simulation of human biped locomotion

    International Nuclear Information System (INIS)

    Ishiguro, Misako; Fujisaki, Masahide

    1988-04-01

    This report describes the numerical simulation of the motion of human-like robot which is one of the research theme of human acts simulation program (HASP) begun at the Computing Center of JAERI in 1987. The purpose of the theme is to model the human motion using robotics kinematic/kinetic equations and to get the joint angles as the solution. As the first trial, we treat the biped locomotion (walking) which is the most fundamental human motion. We implemented a computer program on FACOM M-780 computer, where the program is originated from the book of M. Vukobratovic in Yugoslavia, and made a graphic program to draw a walking shot sequence. Mainly described here are the mathematical model of the biped locomotion, implementation method of the computer program, input data for basic walking pattern, computed results and its validation, and graphic representation of human walking image. Literature survey on robotics equation and biped locomotion is also included. (author)

  14. Muscle Coordination and Locomotion in Humans.

    Science.gov (United States)

    Sylos-Labini, Francesca; Zago, Myrka; Guertin, Pierre A; Lacquaniti, Francesco; Ivanenko, Yury P

    2017-01-01

    Locomotion is a semi-automatic daily task. Several studies show that muscle activity is fairly stereotyped during normal walking. Nevertheless, each human leg contains over 50 muscles and locomotion requires flexibility in order to adapt to different conditions as, for instance, different speeds, gaits, turning, obstacle avoidance, altered gravity levels, etc. Therefore, locomotor control has to deal with a certain level of flexibility and non-linearity. In this review, we describe and discuss different findings dealing with both simplicity and variability of the muscular control, as well as with its maturation during development. Despite complexity and redundancy, muscle activity patterns and spatiotemporal maps of spinal motoneuron output during human locomotion show both stereotypical features as well as functional re-organization. Flexibility and different solutions to adjust motor patterns should be considered when considering new rehabilitation strategies to treat disorders involving deficits in gait. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Analysis of fuel cell hybrid locomotives

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Arnold R. [Vehicle Projects LLC, 621, 17th Street, Suite 2131, Denver, CO 80293 (United States); Peters, John; Smith, Brian E. [Transportation Technology Center Inc., 55500 DOT Road, Pueblo, CO 81007 (United States); Velev, Omourtag A. [AeroVironment Inc., 232 West Maple Avenue, Monrovia, CA 91016 (United States)

    2006-07-03

    Led by Vehicle Projects LLC, an international industry-government consortium is developing a 109t, 1.2MW road-switcher locomotive for commercial and military railway applications. As part of the feasibility and conceptual-design analysis, a study has been made of the potential benefits of a hybrid power plant in which fuel cells comprise the prime mover and a battery or flywheel provides auxiliary power. The potential benefits of a hybrid power plant are: (i) enhancement of transient power and hence tractive effort; (ii) regenerative braking; (iii) reduction of capital cost. Generally, the tractive effort of a locomotive at low speed is limited by wheel adhesion and not by available power. Enhanced transient power is therefore unlikely to benefit a switcher locomotive, but could assist applications that require high acceleration, e.g. subway trains with all axles powered. In most cases, the value of regeneration in locomotives is minimal. For low-speed applications such as switchers, the available kinetic energy and the effectiveness of traction motors as generators are both minimal. For high-speed heavy applications such as freight, the ability of the auxiliary power device to absorb a significant portion of the available kinetic energy is low. Moreover, the hybrid power plant suffers a double efficiency penalty, namely, losses occur in both absorbing and then releasing energy from the auxiliary device, which result in a net storage efficiency of no more than 50% for present battery technology. Capital cost in some applications may be reduced. Based on an observed locomotive duty cycle, a cost model shows that a hybrid power plant for a switcher may indeed reduce capital cost. Offsetting this potential benefit are the increased complexity, weight and volume of the power plant, as well as 20-40% increased fuel consumption that results from lower efficiency. Based on this analysis, the consortium has decided to develop a pure fuel cell road-switcher locomotive, that

  16. DESIGN IMPROVEMENT OF THE LOCOMOTIVE RUNNING GEARS

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2013-09-01

    Full Text Available Purpose. To determine the dynamic qualities of the mainline freight locomotives characterizing the safe motion in tangent and curved track sections at all operational speeds, one needs a whole set of studies, which includes a selection of the design scheme, development of the corresponding mathematical model of the locomotive spatial fluctuations, construction of the computer calculation program, conducting of the theoretical and then experimental studies of the new designs. In this case, one should compare the results with existing designs. One of the necessary conditions for the qualitative improvement of the traction rolling stock is to define the parameters of its running gears. Among the issues related to this problem, an important place is occupied by the task of determining the locomotive dynamic properties on the stage of projection, taking into account the selected technical solutions in the running gear design. Methodology. The mathematical modeling studies are carried out by the numerical integration method of the dynamic loading for the mainline locomotive using the software package «Dynamics of Rail Vehicles » («DYNRAIL». Findings. As a result of research for the improvement of locomotive running gear design it can be seen that the creation of the modern locomotive requires from engineers and scientists the realization of scientific and technical solutions. The solutions enhancing design speed with simultaneous improvement of the traction, braking and dynamic qualities to provide a simple and reliable design, especially the running gear, reducing the costs for maintenance and repair, low initial cost and operating costs for the whole service life, high traction force when starting, which is as close as possible to the ultimate force of adhesion, the ability to work in multiple traction mode and sufficient design speed. Practical Value. The generalization of theoretical, scientific and methodological, experimental studies aimed

  17. Locomotion of Paramecium in patterned environments

    Science.gov (United States)

    Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

    2011-10-01

    Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

  18. Boldness and intermittent locomotion in the bluegill sunfish, Lepomis macrochirus

    OpenAIRE

    Alexander D.M. Wilson; Jean-Guy J. Godin

    2009-01-01

    Intermittent locomotion, characterized by moves interspersed with pauses, is a common pattern of locomotion in animals, but its ecological and evolutionary significance relative to continuous locomotion remains poorly understood. Although many studies have examined individual differences in both intermittent locomotion and boldness separately, to our knowledge, no study to date has investigated the relationship between these 2 traits. Characterizing and understanding this relationship is impo...

  19. Bioinspired template-based control of legged locomotion

    OpenAIRE

    Ahmad Sharbafi, Maziar

    2018-01-01

    cient and robust locomotion is a crucial condition for the more extensive use of legged robots in real world applications. In that respect, robots can learn from animals, if the principles underlying locomotion in biological legged systems can be transferred to their artificial counterparts. However, legged locomotion in biological systems is a complex and not fully understood problem. A great progress to simplify understanding locomotion dynamics and control was made by introducing simple mo...

  20. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not more...

  1. Lizard locomotion in heterogeneous granular media

    Science.gov (United States)

    Schiebel, Perrin; Goldman, Daniel

    2014-03-01

    Locomotion strategies in heterogeneous granular environments (common substrates in deserts), are relatively unexplored. The zebra-tailed lizard (C. draconoides) is a useful model organism for such studies owing to its exceptional ability to navigate a variety of desert habitats at impressive speed (up to 50 body-lengths per second) using both quadrapedal and bidepal gaits. In laboratory experiments, we challenge the lizards to run across a field of boulders (2.54 cm diameter glass spheres or 3.8 cm 3D printed spheres) placed in a lattice pattern and embedded in a loosely packed granular medium of 0.3 mm diameter glass particles. Locomotion kinematics of the lizard are recorded using high speed cameras, with and without the scatterers. The data reveals that unlike the lizard's typical quadrupedal locomotion using a diagonal gait, when scatterers are present the lizard is most successful when using a bipedal gait, with a raised center of mass (CoM). We propose that the kinematics of bipedal running in conjunction with the lizard's long toes and compliant hind foot are the keys to this lizard's successful locomotion in the presence of such obstacles. NSF PoLS

  2. 49 CFR 229.129 - Locomotive horn.

    Science.gov (United States)

    2010-10-01

    .... The locomotive shall be positioned on straight, level track. (6) Measurements shall be taken only when... between 20 percent and 95 percent inclusively; wind velocity is not more than 12 miles per hour and there..., at an angle no greater than 20 degrees from the center line of the track, and oriented with respect...

  3. 77 FR 75045 - Locomotive Safety Standards

    Science.gov (United States)

    2012-12-19

    ...; and, locomotive diesel exhaust. In addition to the issues raised in the petitions, FRA has determined... flow method (AFM) indicator calibration date on the Form 6180-49A; the duration of the remote control... in the context of its use. For example, fuel injectors might possibly be considered as providing...

  4. Morphological self stabilization of locomotion gaits: illustration on a few examples from bio-inspired locomotion

    OpenAIRE

    Chevallereau , Christine; Boyer , Frédéric; Porez , Mathieu; Mauny , Johan; Aoustin , Yannick

    2017-01-01

    International audience; — To a large extent, robotics locomotion can be viewed as cyclic motions, named gaits. Due to the high complexity of the locomotion dynamics, to find the control laws that ensure an expected gait and its stability with respect to external perturbations, is a challenging issue for feedback control. To address this issue, a promising way is to take inspiration from animals that intensively exploit the interactions of the passive degrees of freedom of their body with thei...

  5. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...

  6. Switching Phenomena

    Science.gov (United States)

    Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Mazza, M. G.; Kumar, P.; Plerou, V.; Preis, T.; Stokely, K.; Xu, L.

    One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines can suddenly "switch" from one behavior to another, even though they possess no perfect metronome in time. As if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many temporal patterns in physics, economics, and medicine and even begin to characterize the switching phenomena that enable a system to pass from one state to another. We discuss some applications of correlated randomness to understanding switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water's anomalies are related to a switching point (which is not unlike the "tipping point" immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not "outliers" (another Gladwell immortalization).

  7. Locomotive Schedule Optimization for Da-qin Heavy Haul Railway

    Directory of Open Access Journals (Sweden)

    Ruiye Su

    2015-01-01

    Full Text Available The main difference between locomotive schedule of heavy haul railways and that of regular rail transportation is the number of locomotives utilized for one train. One heavy-loaded train usually has more than one locomotive, but a regular train only has one. This paper develops an optimization model for the multilocomotive scheduling problem (MLSP through analyzing the current locomotive schedule of Da-qin Railway. The objective function of our paper is to minimize the total number of utilized locomotives. The MLSP is nondeterministic polynomial (NP hard. Therefore, we convert the multilocomotive traction problem into a single-locomotive traction problem. Then, the single-locomotive traction problem (SLTP can be converted into an assignment problem. The Hungarian algorithm is applied to solve the model and obtain the optimal locomotive schedule. We use the variance of detention time of locomotives at stations to evaluate the stability of locomotive schedule. In order to evaluate the effectiveness of the proposed optimization model, case studies for 20 kt and 30 kt heavy-loaded combined trains on Da-qin Railway are both conducted. Compared to the current schedules, the optimal schedules from the proposed models can save 62 and 47 locomotives for 20 kt and 30 kt heavy-loaded combined trains, respectively. Therefore, the effectiveness of the proposed model and its solution algorithm are both valid.

  8. Development of a Novel Locomotion Algorithm for Snake Robot

    International Nuclear Information System (INIS)

    Khan, Raisuddin; Billah, Md Masum; Watanabe, Mitsuru; Shafie, A A

    2013-01-01

    A novel algorithm for snake robot locomotion is developed and analyzed in this paper. Serpentine is one of the renowned locomotion for snake robot in disaster recovery mission to overcome narrow space navigation. Several locomotion for snake navigation, such as concertina or rectilinear may be suitable for narrow spaces, but is highly inefficient if the same type of locomotion is used even in open spaces resulting friction reduction which make difficulties for snake movement. A novel locomotion algorithm has been proposed based on the modification of the multi-link snake robot, the modifications include alterations to the snake segments as well elements that mimic scales on the underside of the snake body. Snake robot can be able to navigate in the narrow space using this developed locomotion algorithm. The developed algorithm surmount the others locomotion limitation in narrow space navigation

  9. [Job stress in locomotive attendants in a locomotive depot and related influencing factors].

    Science.gov (United States)

    Kang, L; Jia, X C; Lu, F; Zhou, W H; Chen, R

    2017-10-20

    Objective: To investigate the current status of job stress in locomotive attendants in a locomotive depot and related influencing factors. Methods: From 2012 to 2013, cluster sampling was used to select 1500 locomotive attendants in a locomotive depot in Zhengzhou Railway Bureau as respondents.The contents of the investigation included general data and occupational information.A job satisfaction questionnaire was used to investigate the degree of satisfaction, a depression scale was used to investigate the frequency of symptoms, and a daily stress scale was used to investigate the frequency of fatigue and stress. Results: There was a significant difference in depression score between locomotive attendants with different ages, working years, degrees of education, working situations of spouse, total monthly family incomes, numbers of times of attendanceat night, monthly numbers of times of attendance,ormonthly attendance times( P job satisfaction score between locomotive attendants with different ages,working years, degrees of education, working situations of spouse, total monthly family incomes, numbers of times of attendance at night, monthly attendance times,or ways to work( P job satisfaction( β =1.546)and monthly number of times of attendance,working years,attendance time at night,and degree of education were negatively correlated with job satisfaction( β =-0.185,-0.097,-0.020,and -1.106); monthly number of times of attendance andcommute time were positively correlated with depression( β =0.243 and 0.029); attendance time at night,working situation of spouse,commute time,monthly number of times of attendance,degree of education,and working years were positively correlated with daily stress( β =0.006,0.473,0.010,0.043,0.585, and 0.028). Conclusion: Number of times of attendance, attendance time,working years,and spouse are influencing factors for job stress in locomotive attendants. Improvement in work process and care for their personal life help to reduce

  10. Analysis of emotionality and locomotion in radio-frequency electromagnetic radiation exposed rats.

    Science.gov (United States)

    Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Paval, Jaijesh; Kedage, Vivekananda; Bhat, M Shankaranarayana; Nayak, Satheesha; Bhat, P Gopalakrishna

    2013-07-01

    In the current study the modulatory role of mobile phone radio-frequency electromagnetic radiation (RF-EMR) on emotionality and locomotion was evaluated in adolescent rats. Male albino Wistar rats (6-8 weeks old) were randomly assigned into the following groups having 12 animals in each group. Group I (Control): they remained in the home cage throughout the experimental period. Group II (Sham exposed): they were exposed to mobile phone in switch-off mode for 28 days, and Group III (RF-EMR exposed): they were exposed to RF-EMR (900 MHz) from an active GSM (Global system for mobile communications) mobile phone with a peak power density of 146.60 μW/cm(2) for 28 days. On 29th day, the animals were tested for emotionality and locomotion. Elevated plus maze (EPM) test revealed that, percentage of entries into the open arm, percentage of time spent on the open arm and distance travelled on the open arm were significantly reduced in the RF-EMR exposed rats. Rearing frequency and grooming frequency were also decreased in the RF-EMR exposed rats. Defecation boli count during the EPM test was more with the RF-EMR group. No statistically significant difference was found in total distance travelled, total arm entries, percentage of closed arm entries and parallelism index in the RF-EMR exposed rats compared to controls. Results indicate that mobile phone radiation could affect the emotionality of rats without affecting the general locomotion.

  11. Using entropy measures to characterize human locomotion.

    Science.gov (United States)

    Leverick, Graham; Szturm, Tony; Wu, Christine Q

    2014-12-01

    Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

  12. Exotendons for assistance of human locomotion

    Directory of Open Access Journals (Sweden)

    van den Bogert Antonie J

    2003-10-01

    Full Text Available Abstract Background Powered robotic exoskeletons for assistance of human locomotion are currently under development for military and medical applications. The energy requirements for such devices are excessive, and this has become a major obstacle for practical applications. Legged locomotion in many animals, however, is very energy efficient. We propose that poly-articular elastic mechanisms are a major contributor to the economy of locomotion in such specialized animals. Consequently, it should be possible to design unpowered assistive devices that make effective use of similar mechanisms. Methods A passive assistive technology is presented, based on long elastic cords attached to an exoskeleton and guided by pulleys placed at the joints. A general optimization procedure is described for finding the best geometrical arrangement of such "exotendons" for assisting a specific movement. Optimality is defined either as minimal residual joint moment or as minimal residual joint power. Four specific exotendon systems with increasing complexity are considered. Representative human gait data were used to optimize each of these four systems to achieve maximal assistance for normal walking. Results The most complex exotendon system, with twelve pulleys per limb, was able to reduce the joint moments required for normal walking by 71% and joint power by 74%. A simpler system, with only three pulleys per limb, could reduce joint moments by 46% and joint power by 47%. Conclusion It is concluded that unpowered passive elastic devices can substantially reduce the muscle forces and the metabolic energy needed for walking, without requiring a change in movement. When optimally designed, such devices may allow independent locomotion in patients with large deficits in muscle function.

  13. Chaotic exploration and learning of locomotion behaviors.

    Science.gov (United States)

    Shim, Yoonsik; Husbands, Phil

    2012-08-01

    We present a general and fully dynamic neural system, which exploits intrinsic chaotic dynamics, for the real-time goal-directed exploration and learning of the possible locomotion patterns of an articulated robot of an arbitrary morphology in an unknown environment. The controller is modeled as a network of neural oscillators that are initially coupled only through physical embodiment, and goal-directed exploration of coordinated motor patterns is achieved by chaotic search using adaptive bifurcation. The phase space of the indirectly coupled neural-body-environment system contains multiple transient or permanent self-organized dynamics, each of which is a candidate for a locomotion behavior. The adaptive bifurcation enables the system orbit to wander through various phase-coordinated states, using its intrinsic chaotic dynamics as a driving force, and stabilizes on to one of the states matching the given goal criteria. In order to improve the sustainability of useful transient patterns, sensory homeostasis has been introduced, which results in an increased diversity of motor outputs, thus achieving multiscale exploration. A rhythmic pattern discovered by this process is memorized and sustained by changing the wiring between initially disconnected oscillators using an adaptive synchronization method. Our results show that the novel neurorobotic system is able to create and learn multiple locomotion behaviors for a wide range of body configurations and physical environments and can readapt in realtime after sustaining damage.

  14. On the rules for aquatic locomotion

    Science.gov (United States)

    Saadat, M.; Fish, F. E.; Domel, A. G.; Di Santo, V.; Lauder, G. V.; Haj-Hariri, H.

    2017-08-01

    We present unifying rules governing the efficient locomotion of swimming fish and marine mammals. Using scaling and dimensional analysis, supported by new experimental data, we show that efficient locomotion occurs when the values of the Strouhal (St) number St (=f A /U ) and A*(=A /L ) , two nondimensional numbers that relate forward speed U , tail-beat amplitude A , tail-beat frequency f , and the length of the swimmer L are bound to the tight ranges of 0.2-0.4 and 0.1-0.3, respectively. The tight range of 0.2-0.4 for the St number has previously been associated with optimal thrust generation. We show that the St number alone is insufficient to achieve optimal aquatic locomotion, and an additional condition on A* is needed. More importantly, we show that when swimming at minimal power consumption, the Strouhal number of a cruising swimmer is predetermined solely by the shape and drag characteristics of the swimmer. We show that diverse species of fish and cetaceans cruise indeed with the St number and A* predicted by our theory. Our findings provide a physical explanation as to why fast aquatic swimmers cruise with a relatively constant tail-beat amplitude of approximately 20% of the body length, and their swimming speed is nearly proportional to their tail-beat frequency.

  15. Axial dynamics during locomotion in vertebrates: lesson from the salamander

    OpenAIRE

    GOSSARD, JEAN-PIERRE; DUBUC, RÉJEAN; KOLTA, ARLETTE; Cabelguen, Jean-Marie; Ijspeert, Auke; Lamarque, Stéphanie; Ryczko, Dimitri

    2010-01-01

    Much of what we know about the flexibility of the locomotor networks in vertebrates is derived from studies examining the adaptation of limb movements during stepping in various conditions. However, the body movements play important roles during locomotion: they produce the thrust during undulatory locomotion and they help to increase the stride length during legged locomotion. In this chapter, we review our current knowledge about the flexibility in the neuronal circuits controlling the body...

  16. The Need for Speed in Rodent Locomotion Analyses

    OpenAIRE

    Batka, Richard J.; Brown, Todd J.; Mcmillan, Kathryn P.; Meadows, Rena M.; Jones, Kathryn J.; Haulcomb, Melissa M.

    2014-01-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript,...

  17. Advanced aftertreatment systems for locomotive applications; Moderne Abgasnachbehandlungssysteme fuer Lokomotiven

    Energy Technology Data Exchange (ETDEWEB)

    Park, Paul [Caterpillar Inc., Peoria, IL (United States); Bruestle, Claus [Emitec Inc., Rochester Hill, MI (United States)

    2013-07-15

    Tier 4 legislation for locomotives, starting in 2015, will require significant reductions in particulate matter and nitrogen oxide tail pipe emissions. To reduce nitrogen oxide emissions of line-haul locomotives at least to the level of Tier 4, Caterpillar has developed an aftertreatment system. Here, for the first time an SCR system was used for diesel locomotive engines with an urea dosing system. (orig.)

  18. The Need for Speed in Rodent Locomotion Analyses

    Science.gov (United States)

    Batka, Richard J.; Brown, Todd J.; Mcmillan, Kathryn P.; Meadows, Rena M.; Jones, Kathryn J.; Haulcomb, Melissa M.

    2016-01-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R2 value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. PMID:24890845

  19. Combining Bio-inspired Sensing with Bio-inspired Locomotion

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model that modula......In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model...

  20. Morphological self stabilization of locomotion gaits: illustration on a few examples from bio-inspired locomotion.

    Science.gov (United States)

    Chevallereau, Christine; Boyer, Frédéric; Porez, Mathieu; Mauny, Johan; Aoustin, Yannick

    2017-06-20

    To a large extent, robotics locomotion can be viewed as cyclic motions, named gaits. Due to the high complexity of the locomotion dynamics, to find the control laws that ensure an expected gait and its stability with respect to external perturbations, is a challenging issue for feedback control. To address this issue, a promising way is to take inspiration from animals that intensively exploit the interactions of the passive degrees of freedom of their body with their physical surroundings, to outsource the high-level exteroceptive feedback control to low-level proprioceptive ones. In this case, passive interactions can ensure most of the expected control goals. In this article, we propose a methodological framework to study the role of morphology in the design of locomotion gaits and their stability. This framework ranges from modelling to control aspects, and is illustrated through three examples from bio-inspired locomotion: a three-dimensional micro air vehicle in hovering flight, a pendular planar climber and a bipedal planar walker. In these three cases, we will see how simple considerations based on the morphology of the body can ensure the existence of passive stable gaits without requiring any high-level control.

  1. Performance requirements for locomotive braking systems

    CSIR Research Space (South Africa)

    Vermaak, P

    2000-02-01

    Full Text Available operated “Neutral Brake”. This brake may become active immediately or after a certain time delay when the controller is placed in the neutral position or moved into the neutral position by the “dead-man’s device”. Because this brake will interfere... in testing emergency brake systems due to the inherent braking action of the service brakes and/or locomotive controllers; • Potential problems limitations to braking effort associated with the prime movers and/or hydraulic systems on hydrostatically...

  2. Coupling of cytoskeleton functions for fibroblast locomotion

    DEFF Research Database (Denmark)

    Couchman, J R; Lenn, M; Rees, D A

    1985-01-01

    caused visible protrusions in projected positions at the leading edge. We conclude that fibroblast locomotion may be driven coordinately by a common set of motility mechanisms and that this coordination may be lost as a result of physical or pharmacological disturbance. Taking our evidence with results...... from other Laboratories, we propose the following cytoskeleton functions. (i) Protrusive activity, probably based on solation--gelation cycles of the actin based cytoskeleton and membrane recycling which provides cellular and membrane components for streaming through the cell body to the leading edge...

  3. Proprioceptive Actuation Design for Dynamic Legged locomotion

    Science.gov (United States)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  4. 49 CFR 232.105 - General requirements for locomotives.

    Science.gov (United States)

    2010-10-01

    ... locomotives. (a) The air brake equipment on a locomotive shall be in safe and suitable condition for service... set pressure at any service application with the brakes control valve in the freight position. If such... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRAKE SYSTEM SAFETY STANDARDS FOR FREIGHT AND OTHER NON-PASSENGER...

  5. 49 CFR 230.106 - Steam locomotive frame.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive frame. 230.106 Section 230.106... Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance and inspection. Frames, decks, plates, tailpieces, pedestals, and braces shall be maintained in a safe and...

  6. Locomotive emissions measurements for various blends of biodiesel fuel.

    Science.gov (United States)

    2014-12-01

    The objective of this project was to assess the effects of various blends of biodiesel on locomotive engine exhaust emissions. The : emission tests were conducted on two locomotive models, a Tier 2 EMD SD70ACe and a Tier 1 Plus GE Dash9-44CW, using t...

  7. 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.

  8. Architectures of soft robotic locomotion enabled by simple mechanical principles.

    Science.gov (United States)

    Zhu, Liangliang; Cao, Yunteng; Liu, Yilun; Yang, Zhe; Chen, Xi

    2017-06-28

    In nature, a variety of limbless locomotion patterns flourish, from the small or basic life forms (Escherichia coli, amoebae, etc.) to the large or intelligent creatures (e.g., slugs, starfishes, earthworms, octopuses, jellyfishes, and snakes). Many bioinspired soft robots based on locomotion have been developed in the past few decades. In this work, based on the kinematics and dynamics of two representative locomotion modes (i.e., worm-like crawling and snake-like slithering), we propose a broad set of innovative designs for soft mobile robots through simple mechanical principles. Inspired by and going beyond the existing biological systems, these designs include 1-D (dimensional), 2-D, and 3-D robotic locomotion patterns enabled by the simple actuation of continuous beams. We report herein over 20 locomotion modes achieving various locomotion functions, including crawling, rising, running, creeping, squirming, slithering, swimming, jumping, turning, turning over, helix rolling, wheeling, etc. Some are able to reach high speed, high efficiency, and overcome obstacles. All these locomotion strategies and functions can be integrated into a simple beam model. The proposed simple and robust models are adaptive for severe and complex environments. These elegant designs for diverse robotic locomotion patterns are expected to underpin future deployments of soft robots and to inspire a series of advanced designs.

  9. Modular control of limb movements during human locomotion

    NARCIS (Netherlands)

    Ivanenko, Yuri P; Cappellini, Germana; Dominici, Nadia; Poppele, Richard E; Lacquaniti, Francesco

    2007-01-01

    The idea that the CNS may control complex interactions by modular decomposition has received considerable attention. We explored this idea for human locomotion by examining limb kinematics. The coordination of limb segments during human locomotion has been shown to follow a planar law for walking at

  10. The Determination of the Asynchronous Traction Motor Characteristics of Locomotive

    Directory of Open Access Journals (Sweden)

    Pavel Grigorievich Kolpakhchyan

    2017-01-01

    Full Text Available The article deals with the problem of the locomotive asynchronous traction motor control with the AC diesel-electric transmission. The limitations of the torque of the traction motor when powered by the inverter are determined. The recommendations to improve the use of asynchronous traction motor of locomotives with the AC diesel-electric transmission are given.

  11. Locomotion Gait Planning of Climber Snake-Like Robot

    Directory of Open Access Journals (Sweden)

    Mohammad Nezaminia

    2013-04-01

    Full Text Available In this article a novel breed of snake-like climber robots has been introduced. Structure and operation of the first generation of snake-like climber robot "Marak I" has been discussed. The gait planning for two dimensional locomotion of a novel snake-like climber robot "Marak I" is presented. The types of locomotion investigated were rectilinear and wheeling gaits. The gaits of locomotion were experimented and their suitability for various applications has been mentioned. Some encountered practical problems plus solutions were addressed. Finally we found out that: the vertical motion was producing more fault than horizontal locomotion, and notably the fastest gait of locomotion was the wheeling gait

  12. Switched on!

    CERN Multimedia

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  13. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Discrete-mode steady-state emission... Procedures § 1033.515 Discrete-mode steady-state emission tests of locomotives and locomotive engines. This... a warm-up followed by a sequence of nominally steady-state discrete test modes, as described in...

  14. Cerebellar contribution to feedforward control of locomotion.

    Science.gov (United States)

    Pisotta, Iolanda; Molinari, Marco

    2014-01-01

    The cerebellum is an important contributor to feedforward control mechanisms of the central nervous system, and sequencing-the process that allows spatial and temporal relationships between events to be recognized-has been implicated as the fundamental cerebellar mode of operation. By adopting such a mode and because cerebellar activity patterns are sensitive to a variety of sensorimotor-related tasks, the cerebellum is believed to support motor and cognitive functions that are encoded in the frontal and parietal lobes of the cerebral cortex. In this model, the cerebellum is hypothesized to make predictions about the consequences of a motor or cognitive command that originates from the cortex to prepare the entire system to cope with ongoing changes. In this framework, cerebellar predictive mechanisms for locomotion are addressed, focusing on sensorial and motoric sequencing. The hypothesis that sequence recognition is the mechanism by which the cerebellum functions in gait control is presented and discussed.

  15. Slipping slender bodies and enhanced flagellar locomotion

    Science.gov (United States)

    Man, Yi; Lauga, Eric

    2017-11-01

    In the biological world, many cells exploit slender appendages to swim, include numerous species of bacteria, algae and spermatozoa. A classical method to describe the flow field around such appendages is slender-body theory (SBT), which is often used to study flagellar motility in Newtonian fluids. However, biology environments are often rheologically complex due to the presence of polymers. These polymers generically phase-separate near rigid boundaries where low-viscosity fluid layers lead to effective slip on the surface. In this talk, we present an analytical derivation of SBT in the case where the no-slip boundary condition on the appendage is replaced by a Navier slip boundary condition. Our results demonstrate in particular a systematic reduction of the resistance coefficient of the slender filaments in their tangential direction, which leads to enhanced flagellar locomotion.

  16. Dynamic legged locomotion in robots and animals

    Science.gov (United States)

    Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

    1995-01-01

    This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

  17. Digital switched hydraulics

    Science.gov (United States)

    Pan, Min; Plummer, Andrew

    2018-06-01

    This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

  18. A survey report for the turning of biped locomotion robot

    International Nuclear Information System (INIS)

    Kato, Ichiro; Takanishi, Atsuo; Kume, Etsuo.

    1992-12-01

    A mechanical design study of biped locomotion robots is going on at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report for the turning of biped locomotion robot: the WL-10R designed and developed at Waseda University. This report includes the control method of turning, machine model and control system. (author)

  19. Distribution of spinal neuronal networks controlling forward and backward locomotion.

    Science.gov (United States)

    Merkulyeva, Natalia; Veshchitskii, Aleksandr; Gorsky, Oleg; Pavlova, Natalia; Zelenin, Pavel V; Gerasimenko, Yury; Deliagina, Tatiana G; Musienko, Pavel

    2018-04-20

    Higher vertebrates, including humans, are capable not only of forward (FW) locomotion but also of walking in other directions relative to the body axis [backward (BW), sideways, etc.]. While the neural mechanisms responsible for controlling FW locomotion have been studied in considerable detail, the mechanisms controlling steps in other directions are mostly unknown. The aim of the present study was to investigate the distribution of spinal neuronal networks controlling FW and BW locomotion. First, we applied electrical epidural stimulation (ES) to different segments of the spinal cord from L2 to S2 to reveal zones triggering FW and BW locomotion in decerebrate cats of either sex. Second, to determine the location of spinal neurons activated during FW and BW locomotion, we used c-fos immunostaining. We found that the neuronal networks responsible for FW locomotion were distributed broadly in the lumbosacral spinal cord and could be activated by ES of any segment from L3 to S2. By contrast, networks generating BW locomotion were activated by ES of a limited zone from the caudal part of L5 to the caudal part of L7. In the intermediate part of the gray matter within this zone, a significantly higher number of c- fos -positive interneurons was revealed in BW-stepping cats compared with FW-stepping cats. We suggest that this region of the spinal cord contains the network that determines the BW direction of locomotion. Significance Statement Sequential and single steps in various directions relative to the body axis [forward (FW), backward (BW), sideways, etc.] are used during locomotion and to correct for perturbations, respectively. The mechanisms controlling step direction are unknown. In the present study, for the first time we compared the distributions of spinal neuronal networks controlling FW and BW locomotion. Using a marker to visualize active neurons, we demonstrated that in the intermediate part of the gray matter within L6 and L7 spinal segments

  20. 49 CFR 230.90 - Draw gear between steam locomotive and tender.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Draw gear between steam locomotive and tender. 230... Steam Locomotives and Tenders Draw Gear and Draft Systems § 230.90 Draw gear between steam locomotive and tender. (a) Maintenance and testing. The draw gear between the steam locomotive and tender...

  1. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive leading...

  2. Dynamic Locomotion With Four and Six-Legged Robots

    National Research Council Canada - National Science Library

    Buehler, M; Saranli, U; Papadopoulos, D; Koditschek, D

    2000-01-01

    .... The Scout II quadruped runs on flat ground in a bounding gait, and was motivated by an effort to understand the minimal mechanical design and control complexity for dynamically stable locomotion...

  3. Test requirements of locomotive fuel tank blunt impact tests

    Science.gov (United States)

    2013-10-15

    The Federal Railroad Administrations Office of Research : and Development is conducting research into passenger : locomotive fuel tank crashworthiness. A series of impact tests : are planned to measure fuel tank deformation under two types : of dy...

  4. Review of codes, standards, and regulations for natural gas locomotives.

    Science.gov (United States)

    2014-06-01

    This report identified, collected, and summarized relevant international codes, standards, and regulations with potential : applicability to the use of natural gas as a locomotive fuel. Few international or country-specific codes, standards, and regu...

  5. CPG-based Locomotion Controller Design for a Boxfish-like Robot

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-06-01

    Full Text Available This paper focuses on a Central Pattern Generator (CPG-based locomotion controller design for a boxfish-like robot. The bio-inspired controller is aimed at flexible switching in multiple 3D swimming patterns and exact attitude control of yaw and roll such that the robot will swim more like a real boxfish. The CPG network comprises two layers, the lower layer is the network of coupled linear oscillators and the upper is the transition layer where the lower-dimensional locomotion stimuli are transformed into the higher-dimensional control parameters serving for all the oscillators. Based on such a two-layer framework, flexible switching between multiple three-dimensional swimming patterns, such as swimming forwards/backwards, turning left/right, swimming upwards/downwards and rolling clockwise/counter-clockwise, can be simply realized by inputting different stimuli. Moreover, the stability of the CPG network is strictly proved to guarantee the intrinsic stability of the swimming patterns. As to exact attitude control, based on this open-loop CPG network and the sensory feedback from the Inertial Measurement Unit (IMU, a closed-loop CPG controller is advanced for yaw and roll control of the robotic fish for the first time. This CPG-based online attitude control for a robotic fish will greatly facilitate high-level practical underwater applications. A series of relevant experiments with the robotic fish are conducted systematically to validate the effectiveness and stability of the open-loop and closed-loop CPG controllers.

  6. Latching micro optical switch

    Science.gov (United States)

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  7. Neurobiology of Caenorhabditis elegans Locomotion: Where Do We Stand?

    OpenAIRE

    Gjorgjieva, Julijana; Biron, David; Haspel, Gal

    2014-01-01

    Animals use a nervous system for locomotion in some stage of their life cycle. The nematode Caenorhabditis elegans, a major animal model for almost all fields of experimental biology, has long been used for detailed studies of genetic and physiological locomotion mechanisms. Of its 959 somatic cells, 302 are neurons that are identifiable by lineage, location, morphology, and neurochemistry in every adult hermaphrodite. Of those, 75 motoneurons innervate body wall muscles that provide the thru...

  8. Expression of emotion in the kinematics of locomotion.

    Science.gov (United States)

    Barliya, Avi; Omlor, Lars; Giese, Martin A; Berthoz, Alain; Flash, Tamar

    2013-03-01

    Here, we examine how different emotions-happiness, fear, sadness and anger-affect the kinematics of locomotion. We focus on a compact representation of locomotion properties using the intersegmental law of coordination (Borghese et al. in J Physiol 494(3):863-879, 1996), which states that, during the gait cycle of human locomotion, the elevation angles of the thigh, shank and foot do not evolve independently of each other but form a planar pattern of co-variation. This phenomenon is highly robust and has been extensively studied. The orientation of the plane has been correlated with changes in the speed of locomotion and with reduction in energy expenditure as speed increases. An analytical model explaining the conditions underlying the emergence of this plane and predicting its orientation reveals that it suffices to examine the amplitudes of the elevation angles of the different segments along with the phase shifts between them (Barliya et al. in Exp Brain Res 193:371-385, 2009). We thus investigated the influence of different emotions on the parameters directly determining the orientation of the intersegmental plane and on the angular rotation profiles of the leg segments, examining both the effect of changes in walking speed and effects independent of speed. Subjects were professional actors and naïve subjects with no training in acting. As expected, emotions were found to strongly affect the kinematics of locomotion, particularly walking speed. The intersegmental coordination patterns revealed that emotional expression caused additional modifications to the locomotion patterns that could not be explained solely by a change in speed. For all emotions except sadness, the amplitude of thigh elevation angles changed from those in neutral locomotion. The intersegmental plane was also differently oriented, especially during anger. We suggest that, while speed is the dominant variable allowing discrimination between different emotional gaits, emotion can be

  9. Fluid Mechanics of Aquatic Locomotion at Large Reynolds Numbers

    OpenAIRE

    Govardhan, RN; Arakeri, JH

    2011-01-01

    Abstract | There exist a huge range of fish species besides other aquatic organisms like squids and salps that locomote in water at large Reynolds numbers, a regime of flow where inertial forces dominate viscous forces. In the present review, we discuss the fluid mechanics governing the locomotion of such organisms. Most fishes propel themselves by periodic undulatory motions of the body and tail, and the typical classification of their swimming modes is based on the fraction of their body...

  10. ENERGY EFFICIENCY OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSION TESTS AT LOCOMOTIVE REPAIR PLANT

    Directory of Open Access Journals (Sweden)

    B. E. Bodnar

    2015-10-01

    Full Text Available Purpose. In difficult economic conditions, cost reduction of electricity consumption for the needs of production is an urgent task for the country’s industrial enterprises. Technical specifications of enterprises, which repair diesel locomotive hydraulic transmission, recommend conducting a certain amount of evaluation and regulatory tests to monitor their condition after repair. Experience shows that a significant portion of hydraulic transmission defects is revealed by bench tests. The advantages of bench tests include the ability to detect defects after repair, ease of maintenance of the hydraulic transmission and relatively low labour intensity for eliminating defects. The quality of these tests results in the transmission resource and its efficiency. Improvement of the technology of plant post-repairs hydraulic tests in order to reduce electricity consumption while testing. Methodology. The possible options for hydraulic transmission test bench improvement were analysed. There was proposed an energy efficiency method for diesel locomotive hydraulic transmission testing in locomotive repair plant environment. This is achieved by installing additional drive motor which receives power from the load generator. Findings. Based on the conducted analysis the necessity of improving the plant stand testing of hydraulic transmission was proved. The variants of the stand modernization were examined. The test stand modernization analysis was conducted. Originality. The possibility of using electric power load generator to power the stand electric drive motor or the additional drive motor was theoretically substantiated. Practical value. A variant of hydraulic transmission test stand based on the mutual load method was proposed. Using this method increases the hydraulic transmission load range and power consumption by stand remains unchanged. The additional drive motor will increase the speed of the input shaft that in its turn wil allow testing in

  11. How animals move: comparative lessons on animal locomotion.

    Science.gov (United States)

    Schaeffer, Paul J; Lindstedt, Stan L

    2013-01-01

    Comparative physiology often provides unique insights in animal structure and function. It is specifically through this lens that we discuss the fundamental properties of skeletal muscle and animal locomotion, incorporating variation in body size and evolved difference among species. For example, muscle frequencies in vivo are highly constrained by body size, which apparently tunes muscle use to maximize recovery of elastic recoil potential energy. Secondary to this constraint, there is an expected linking of skeletal muscle structural and functional properties. Muscle is relatively simple structurally, but by changing proportions of the few muscle components, a diverse range of functional outputs is possible. Thus, there is a consistent and predictable relation between muscle function and myocyte composition that illuminates animal locomotion. When animals move, the mechanical properties of muscle diverge from the static textbook force-velocity relations described by A. V. Hill, as recovery of elastic potential energy together with force and power enhancement with activation during stretch combine to modulate performance. These relations are best understood through the tool of work loops. Also, when animals move, locomotion is often conveniently categorized energetically. Burst locomotion is typified by high-power outputs and short durations while sustained, cyclic, locomotion engages a smaller fraction of the muscle tissue, yielding lower force and power. However, closer examination reveals that rather than a dichotomy, energetics of locomotion is a continuum. There is a remarkably predictable relationship between duration of activity and peak sustainable performance.

  12. Multi-modal locomotion: from animal to application

    International Nuclear Information System (INIS)

    Lock, R J; Burgess, S C; Vaidyanathan, R

    2014-01-01

    The majority of robotic vehicles that can be found today are bound to operations within a single media (i.e. land, air or water). This is very rarely the case when considering locomotive capabilities in natural systems. Utility for small robots often reflects the exact same problem domain as small animals, hence providing numerous avenues for biological inspiration. This paper begins to investigate the various modes of locomotion adopted by different genus groups in multiple media as an initial attempt to determine the compromise in ability adopted by the animals when achieving multi-modal locomotion. A review of current biologically inspired multi-modal robots is also presented. The primary aim of this research is to lay the foundation for a generation of vehicles capable of multi-modal locomotion, allowing ambulatory abilities in more than one media, surpassing current capabilities. By identifying and understanding when natural systems use specific locomotion mechanisms, when they opt for disparate mechanisms for each mode of locomotion rather than using a synergized singular mechanism, and how this affects their capability in each medium, similar combinations can be used as inspiration for future multi-modal biologically inspired robotic platforms. (topical review)

  13. Sensory modulation of movement, posture and locomotion.

    Science.gov (United States)

    Saradjian, A H

    2015-11-01

    During voluntary movement, there exists a well known functional sensory attenuation of afferent inputs, which allows us to discriminate between information related to our own movements and those arising from the external environment. This attenuation or 'gating' prevents some signals from interfering with movement elaboration and production. However, there are situations in which certain task-relevant sensory inputs may not be gated. This review begins by identifying the prevalent findings in the literature with specific regard to the somatosensory modality, and reviews the many cases of classical sensory gating phenomenon accompanying voluntary movement and their neural basis. This review also focuses on the newer axes of research that demonstrate that task-specific sensory information may be disinhibited or even facilitated during engagement in voluntary actions. Finally, a particular emphasis will be placed on postural and/or locomotor tasks involving strong somatosensory demands, especially for the setting of the anticipatory postural adjustments observed prior the initiation of locomotion. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Linking pedestrian flow characteristics with stepping locomotion

    Science.gov (United States)

    Wang, Jiayue; Boltes, Maik; Seyfried, Armin; Zhang, Jun; Ziemer, Verena; Weng, Wenguo

    2018-06-01

    While properties of human traffic flow are described by speed, density and flow, the locomotion of pedestrian is based on steps. To relate characteristics of human locomotor system with properties of human traffic flow, this paper aims to connect gait characteristics like step length, step frequency, swaying amplitude and synchronization with speed and density and thus to build a ground for advanced pedestrian models. For this aim, observational and experimental study on the single-file movement of pedestrians at different densities is conducted. Methods to measure step length, step frequency, swaying amplitude and step synchronization are proposed by means of trajectories of the head. Mathematical models for the relations of step length or frequency and speed are evaluated. The problem how step length and step duration are influenced by factors like body height and density is investigated. It is shown that the effect of body height on step length and step duration changes with density. Furthermore, two different types of step in-phase synchronization between two successive pedestrians are observed and the influence of step synchronization on step length is examined.

  15. Advanced underground Vehicle Power and Control: The locomotive Research Platform

    Energy Technology Data Exchange (ETDEWEB)

    Vehicle Projects LLC

    2003-01-28

    Develop a fuelcell mine locomotive with metal-hydride hydrogen storage. Test the locomotive for fundamental limitations preventing successful commercialization of hydride fuelcells in underground mining. During Phase 1 of the DOE-EERE sponsored project, FPI and its partner SNL, completed work on the development of a 14.4 kW fuelcell power plant and metal-hydride energy storage. An existing battery-electric locomotive with similar power requirements, minus the battery module, was used as the base vehicle. In March 2001, Atlas Copco Wagner of Portland, OR, installed the fuelcell power plant into the base vehicle and initiated integration of the system into the vehicle. The entire vehicle returned to Sandia in May 2001 for further development and integration. Initial system power-up took place in December 2001. A revision to the original contract, Phase 2, at the request of DOE Golden Field Office, established Vehicle Projects LLC as the new prime contractor,. Phase 2 allowed industry partners to conduct surface tests, incorporate enhancements to the original design by SNL, perform an extensive risk and safety analysis, and test the fuelcell locomotive underground under representative production mine conditions. During the surface tests one of the fuelcell stacks exhibited reduced power output resulting in having to replace both fuelcell stacks. The new stacks were manufactured with new and improved technology resulting in an increase of the gross power output from 14.4 kW to 17 kW. Further work by CANMET and Hatch Associates, an engineering consulting firm specializing in safety analysis for the mining industry, both under subcontract to Vehicle Projects LLC, established minimum requirements for underground testing. CANMET upgraded the Programmable Logic Control (PLC) software used to monitor and control the fuelcell power plant, taking into account locomotive operator's needs. Battery Electric, a South Africa manufacturer, designed and manufactured (at no cost

  16. Switching Adaptability in Human-Inspired Sidesteps: A Minimal Model.

    Science.gov (United States)

    Fujii, Keisuke; Yoshihara, Yuki; Tanabe, Hiroko; Yamamoto, Yuji

    2017-01-01

    Humans can adapt to abruptly changing situations by coordinating redundant components, even in bipedality. Conventional adaptability has been reproduced by various computational approaches, such as optimal control, neural oscillator, and reinforcement learning; however, the adaptability in bipedal locomotion necessary for biological and social activities, such as unpredicted direction change in chase-and-escape, is unknown due to the dynamically unstable multi-link closed-loop system. Here we propose a switching adaptation model for performing bipedal locomotion by improving autonomous distributed control, where autonomous actuators interact without central control and switch the roles for propulsion, balancing, and leg swing. Our switching mobility model achieved direction change at any time using only three actuators, although it showed higher motor costs than comparable models without direction change. Our method of evaluating such adaptation at any time should be utilized as a prerequisite for understanding universal motor control. The proposed algorithm may simply explain and predict the adaptation mechanism in human bipedality to coordinate the actuator functions within and between limbs.

  17. Problems of locomotive wheel wear in fleet replacement

    Directory of Open Access Journals (Sweden)

    L.P. Lingaytis

    2013-08-01

    Full Text Available Purpose. To conduct a research and find out the causes of defects appearing on the wheel thread of freight locomotives 2М62 and SIEMENS ER20CF. Methodology. To find the ways to solve this problem comparing the locomotive designs and their operating conditions. Findings. After examining the nature of the wheel wear the main difference was found: in locomotives of the 2M62 line wears the wheel flange, and in the locomotives SIEMENS ER20CF – the tread surface. After installation on the 2M62 locomotive the lubrication system of flanges their wear rate significantly decreased. On the new freight locomotives SIEMENS ER20CF the flange lubrication systems of the wheel set have been already installed at the factory, however the wheel thread is wearing. As for locomotives 2M62, and on locomotives SIEMENS ER20CF most wear profile skating wheels of the first wheel set. On both locomotive lines the 2М62 and the SIEMENS ER20CF the tread profile of the first wheel set most of all is subject to the wear. After reaching the 170 000 km run, the tread surface of some wheels begins to crumble. There was a suspicion that the reason for crumb formation of the wheel surface may be insufficient or excessive wheel hardness or its chemical composition. In order to confirm or deny this suspicion the following studies were conducted: the examination of the rim surface, the study of the wheel metal hardness and the document analysis of the wheel production and their comparison with the results of wheel hardness measurement. Practical value. The technical condition of locomotives is one of the bases of safety and reliability of the rolling stock. The reduction of the wheel wear significantly reduces the operating costs of railway transport. After study completion it was found that there was no evidence to suggest that the ratio of the wheel-rail hardness could be the cause of the wheel surface crumbling.

  18. EVALUATION OF DYNAMIC INDICATORS OF SIX-AXLE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2015-04-01

    Full Text Available Purpose. The paper is devoted to dynamic characteristics evaluation of the locomotive with prospective design and determination the feasibility of its use on the Ukrainian railways. Methodology. The methods of mathematical and computer modeling of the dynamics of railway vehicles, as well as methods for the numerical integration of systems of ordinary nonlinear differential equations were used to solve the problem. Findings. The calculated diagram of a locomotive on three-axle bogies was built to solve the problem, and it is a system of rigid bodies connected by various elements of rheology. The mathematical model of the locomotive movement, allowing studying its spatial vibrations at driving on straight and curved sections of the track with random irregularities in plan and profile was developed with use of this calculated diagram. At compiling the mathematical model took into account both geometric (nonlinearity profile of the wheel roll surface and physical nonlinearity of the system (the work forces of dry friction, nonlinearity characteristics of interaction forces between wheels and rails. The multivariate calculations, which allowed assessing the dynamic qualities of the locomotive at its movement along straight and curved sections of the track, were realized with the use of computer modeling. The smoothness movement indicators of the locomotive in horizontal and vertical planes, frame strength, coefficients of vertical dynamics in the first and second stages of the suspension, the load factor of resistance against the derailment of the wheel from the rail were determined at the period of research. In addition, a comparison of the obtained results with similar characteristics is widely used on the Ukrainian railways in six-axle locomotive TE 116. The influence of speed and technical state of the track on the locomotive traffic safety was determined.Originality. A mathematical model of the spatial movement of a six-axle locomotive with

  19. INFORMATION-MEASURING TEST SYSTEM OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSIONS

    Directory of Open Access Journals (Sweden)

    I. V. Zhukovytskyy

    2015-08-01

    Full Text Available Purpose. The article describes the process of developing the information-measuring test system of diesel locomotives hydraulic transmission, which gives the possibility to obtain baseline data to conduct further studies for the determination of the technical condition of diesel locomotives hydraulic transmission. The improvement of factory technology of post-repair tests of hydraulic transmissions by automating the existing hydraulic transmission test stands according to the specifications of the diesel locomotive repair enterprises was analyzed. It is achieved based on a detailed review of existing foreign information-measuring test systems for hydraulic transmission of diesel locomotives, BelAZ earthmover, aircraft tug, slag car, truck, BelAZ wheel dozer, some brands of tractors, etc. The problem for creation the information-measuring test systems for diesel locomotive hydraulic transmission is being solved, starting in the first place from the possibility of automation of the existing test stand of diesel locomotives hydraulic transmission at Dnipropetrovsk Diesel Locomotive Repair Plant "Promteplovoz". Methodology. In the work the researchers proposed the method to create a microprocessor automated system of diesel locomotives hydraulic transmission stand testing in the locomotive plant conditions. It acts by justifying the selection of the necessary sensors, as well as the application of the necessary hardware and software for information-measuring systems. Findings. Based on the conducted analysis there was grounded the necessity of improvement the plant hydraulic transmission stand testing by creating a microprocessor testing system, supported by the experience of developing such systems abroad. Further research should be aimed to improve the accuracy and frequency of data collection by adopting the more modern and reliable sensors in tandem with the use of filtering software for electromagnetic and other interference. Originality. The

  20. Human Locomotion in Hypogravity: From Basic Research to Clinical Applications

    Directory of Open Access Journals (Sweden)

    Francesco Lacquaniti

    2017-11-01

    Full Text Available We have considerable knowledge about the mechanisms underlying compensation of Earth gravity during locomotion, a knowledge obtained from physiological, biomechanical, modeling, developmental, comparative, and paleoanthropological studies. By contrast, we know much less about locomotion and movement in general under sustained hypogravity. This lack of information poses a serious problem for human space exploration. In a near future humans will walk again on the Moon and for the first time on Mars. It would be important to predict how they will move around, since we know that locomotion and mobility in general may be jeopardized in hypogravity, especially when landing after a prolonged weightlessness of the space flight. The combination of muscle weakness, of wearing a cumbersome spacesuit, and of maladaptive patterns of locomotion in hypogravity significantly increase the risk of falls and injuries. Much of what we currently know about locomotion in hypogravity derives from the video archives of the Apollo missions on the Moon, the experiments performed with parabolic flight or with body weight support on Earth, and the theoretical models. These are the topics of our review, along with the issue of the application of simulated hypogravity in rehabilitation to help patients with deambulation problems. We consider several issues that are common to the field of space science and clinical rehabilitation: the general principles governing locomotion in hypogravity, the methods used to reduce gravity effects on locomotion, the extent to which the resulting behavior is comparable across different methods, the important non-linearities of several locomotor parameters as a function of the gravity reduction, the need to use multiple methods to obtain reliable results, and the need to tailor the methods individually based on the physiology and medical history of each person.

  1. Hybrid Locomotion Evaluation for a Novel Amphibious Spherical Robot

    Directory of Open Access Journals (Sweden)

    Huiming Xing

    2018-01-01

    Full Text Available We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III to support the body and slide flexibly on smooth (flat terrain. The composite driving system facilitates two on-land locomotion modes (sliding and walking and underwater locomotion mode with vectored thrusters, improving adaptability to the amphibious environment. Sliding locomotion improves the stability and maneuverability of ASR-III on smooth flat terrain, whereas walking locomotion allows ASR-III to conquer rough terrain. We used both forward and reverse kinematic models to evaluate the walking and sliding gait efficiency. The robot can also realize underwater locomotion with four vectored water-jet thrusters, and is capable of forward motion, heading angle control and depth control. We evaluated LSWM efficiency and the sliding velocities associated with varying extensions of the LSWM. To explore gait stability and mobility, we performed on-land experiments on smooth flat terrain to define the optimal stride length and frequency. We also evaluated the efficacy of waypoint tracking when the sliding gait was employed, using a closed-loop proportional-integral-derivative (PID control mechanism. Moreover, experiments of forward locomotion, heading angle control and depth control were conducted to verify the underwater performance of ASR-III. Comparison of the previous robot and ASR-III demonstrated the ASR-III had better amphibious motion performance.

  2. Human Locomotion in Hypogravity: From Basic Research to Clinical Applications.

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yury P; Sylos-Labini, Francesca; La Scaleia, Valentina; La Scaleia, Barbara; Willems, Patrick A; Zago, Myrka

    2017-01-01

    We have considerable knowledge about the mechanisms underlying compensation of Earth gravity during locomotion, a knowledge obtained from physiological, biomechanical, modeling, developmental, comparative, and paleoanthropological studies. By contrast, we know much less about locomotion and movement in general under sustained hypogravity. This lack of information poses a serious problem for human space exploration. In a near future humans will walk again on the Moon and for the first time on Mars. It would be important to predict how they will move around, since we know that locomotion and mobility in general may be jeopardized in hypogravity, especially when landing after a prolonged weightlessness of the space flight. The combination of muscle weakness, of wearing a cumbersome spacesuit, and of maladaptive patterns of locomotion in hypogravity significantly increase the risk of falls and injuries. Much of what we currently know about locomotion in hypogravity derives from the video archives of the Apollo missions on the Moon, the experiments performed with parabolic flight or with body weight support on Earth, and the theoretical models. These are the topics of our review, along with the issue of the application of simulated hypogravity in rehabilitation to help patients with deambulation problems. We consider several issues that are common to the field of space science and clinical rehabilitation: the general principles governing locomotion in hypogravity, the methods used to reduce gravity effects on locomotion, the extent to which the resulting behavior is comparable across different methods, the important non-linearities of several locomotor parameters as a function of the gravity reduction, the need to use multiple methods to obtain reliable results, and the need to tailor the methods individually based on the physiology and medical history of each person.

  3. System design of a large fuel cell hybrid locomotive

    Science.gov (United States)

    Miller, A. R.; Hess, K. S.; Barnes, D. L.; Erickson, T. L.

    Fuel cell power for locomotives combines the environmental benefits of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. A North American consortium, a public-private partnership, is developing a prototype hydrogen-fueled fuel cell-battery hybrid switcher locomotive for urban and military-base rail applications. Switcher locomotives are used in rail yards for assembling and disassembling trains and moving trains from one point to another. At 127 tonnes (280,000 lb), continuous power of 250 kW from its (proton exchange membrane) PEM fuel cell prime mover, and transient power well in excess of 1 MW, the hybrid locomotive will be the heaviest and most powerful fuel cell land vehicle yet. This fast-paced project calls for completion of the vehicle itself near the end of 2007. Several technical challenges not found in the development of smaller vehicles arise when designing and developing such a large fuel cell vehicle. Weight, center of gravity, packaging, and safety were design factors leading to, among other features, the roof location of the lightweight 350 bar compressed hydrogen storage system. Harsh operating conditions, especially shock loads during coupling to railcars, require component mounting systems capable of absorbing high energy. Vehicle scale-up by increasing mass, density, or power presents new challenges primarily related to issues of system layout, hydrogen storage, heat transfer, and shock loads.

  4. Two-fluid model for locomotion under self-confinement

    Science.gov (United States)

    Reigh, Shang Yik; Lauga, Eric

    2017-09-01

    The bacterium Helicobacter pylori causes ulcers in the stomach of humans by invading mucus layers protecting epithelial cells. It does so by chemically changing the rheological properties of the mucus from a high-viscosity gel to a low-viscosity solution in which it may self-propel. We develop a two-fluid model for this process of swimming under self-generated confinement. We solve exactly for the flow and the locomotion speed of a spherical swimmer located in a spherically symmetric system of two Newtonian fluids whose boundary moves with the swimmer. We also treat separately the special case of an immobile outer fluid. In all cases, we characterize the flow fields, their spatial decay, and the impact of both the viscosity ratio and the degree of confinement on the locomotion speed of the model swimmer. The spatial decay of the flow retains the same power-law decay as for locomotion in a single fluid but with a decreased magnitude. Independent of the assumption chosen to characterize the impact of confinement on the actuation applied by the swimmer, its locomotion speed always decreases with an increase in the degree of confinement. Our modeling results suggest that a low-viscosity region of at least six times the effective swimmer size is required to lead to swimming with speeds similar to locomotion in an infinite fluid, corresponding to a region of size above ≈25 μ m for Helicobacter pylori.

  5. Towards a general neural controller for quadrupedal locomotion.

    Science.gov (United States)

    Maufroy, Christophe; Kimura, Hiroshi; Takase, Kunikatsu

    2008-05-01

    Our study aims at the design and implementation of a general controller for quadruped locomotion, allowing the robot to use the whole range of quadrupedal gaits (i.e. from low speed walking to fast running). A general legged locomotion controller must integrate both posture control and rhythmic motion control and have the ability to shift continuously from one control method to the other according to locomotion speed. We are developing such a general quadrupedal locomotion controller by using a neural model involving a CPG (Central Pattern Generator) utilizing ground reaction force sensory feedback. We used a biologically faithful musculoskeletal model with a spine and hind legs, and computationally simulated stable stepping motion at various speeds using the neuro-mechanical system combining the neural controller and the musculoskeletal model. We compared the changes of the most important locomotion characteristics (stepping period, duty ratio and support length) according to speed in our simulations with the data on real cat walking. We found similar tendencies for all of them. In particular, the swing period was approximately constant while the stance period decreased with speed, resulting in a decreasing stepping period and duty ratio. Moreover, the support length increased with speed due to the posterior extreme position that shifted progressively caudally, while the anterior extreme position was approximately constant. This indicates that we succeeded in reproducing to some extent the motion of a cat from the kinematical point of view, even though we used a 2D bipedal model. We expect that such computational models will become essential tools for legged locomotion neuroscience in the future.

  6. Economic aspects of advanced coal-fired gas turbine locomotives

    Science.gov (United States)

    Liddle, S. G.; Bonzo, B. B.; Houser, B. C.

    1983-01-01

    Increases in the price of such conventional fuels as Diesel No. 2, as well as advancements in turbine technology, have prompted the present economic assessment of coal-fired gas turbine locomotive engines. A regenerative open cycle internal combustion gas turbine engine may be used, given the development of ceramic hot section components. Otherwise, an external combustion gas turbine engine appears attractive, since although its thermal efficiency is lower than that of a Diesel engine, its fuel is far less expensive. Attention is given to such a powerplant which will use a fluidized bed coal combustor. A life cycle cost analysis yields figures that are approximately half those typical of present locomotive engines.

  7. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... is established as a flexible means to reduce the optical buffer, e.g., the number of fibre delay lines for a 16x16 switch block is reduced from 23 to 6 by going from 2 to 8 wavelength channels pr. inlet. Additionally, a component count analysis is carried out to illustrate the trade-offs in the switch block...

  8. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  9. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  10. Dynamic processes during monorail locomotive rocking and their impact on draw gear characteristics

    Directory of Open Access Journals (Sweden)

    Viktor GUTAREVICH

    2011-01-01

    Full Text Available The article discusses the motion of the suspended monorail locomotive, interrelation between the parameters of irregularities false path and lateral rocking monorail locomotive, the values of lateral deviation for the different speeds on the monorail.

  11. Dynamic processes during monorail locomotive rocking and their impact on draw gear characteristics

    OpenAIRE

    Viktor GUTAREVICH

    2011-01-01

    The article discusses the motion of the suspended monorail locomotive, interrelation between the parameters of irregularities false path and lateral rocking monorail locomotive, the values of lateral deviation for the different speeds on the monorail.

  12. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Science.gov (United States)

    2010-10-01

    ... 31, 2015, a train controlled by a locomotive with an onboard PTC apparatus that has failed en route... III railroad, including a tourist or excursion railroad, and controlled by a locomotive not equipped...

  13. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  14. Elements of magnetic switching

    International Nuclear Information System (INIS)

    Aaland, K.

    1983-01-01

    This chapter describes magnetic switching as a method of connecting a capacitor bank (source) to a load; reviews several successful applications of magnetic switching, and discusses switching transformers, limitations and future possibilities. Some of the inflexibility and especially the high cost of magnetic materials may be overcome with the availability of the new splash cooled ribbons (Metglas). Experience has shown that magnetics works despite shock, radiation or noise interferences

  15. Pemodelan Markov Switching Autoregressive

    OpenAIRE

    Ariyani, Fiqria Devi; Warsito, Budi; Yasin, Hasbi

    2014-01-01

    Transition from depreciation to appreciation of exchange rate is one of regime switching that ignored by classic time series model, such as ARIMA, ARCH, or GARCH. Therefore, economic variables are modeled by Markov Switching Autoregressive (MSAR) which consider the regime switching. MLE is not applicable to parameters estimation because regime is an unobservable variable. So that filtering and smoothing process are applied to see the regime probabilities of observation. Using this model, tran...

  16. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of non-complying steam locomotives. 230... General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a) General limitations on movement. A steam locomotive with one or more non-complying conditions may be moved only as a...

  17. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and XX-52-67...

  18. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Science.gov (United States)

    2010-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with glazing...

  19. Transient-Switch-Signal Suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

  20. Optimal switching using coherent control

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Heuck, Mikkel; Mørk, Jesper

    2013-01-01

    that the switching time, in general, is not limited by the cavity lifetime. Therefore, the total energy required for switching is a more relevant figure of merit than the switching speed, and for a particular two-pulse switching scheme we use calculus of variations to optimize the switching in terms of input energy....

  1. Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

    Science.gov (United States)

    Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

  2. Energetic extremes in aquatic locomotion by coral reef fishes.

    Directory of Open Access Journals (Sweden)

    Christopher J Fulton

    Full Text Available Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1 while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting, streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.

  3. Designing presence for real locomotion in immersive virtual environments

    DEFF Research Database (Denmark)

    Turchet, Luca

    2015-01-01

    This paper describes a framework for designing systems for real locomotion in virtual environments (VEs) in order to achieve an intense sense of presence. The main outcome of the present research is a list of design features that the virtual reality technology should have in order to achieve...

  4. A light-weight, yet powerful diesel locomotive from Vossloh

    Energy Technology Data Exchange (ETDEWEB)

    Marti, Mariano [Vossloh Rail Vehicles, Albuixech/Valencia (Spain)

    2013-05-15

    The EUROLIGHT is an eight-wheeled diesel-electric locomotive developed by Vossloh Rail Vehicles for interoperable rail traffic. With its low axle load of less than 20 tonnes, it can be deployed flexibly on both main lines and secondary ones.

  5. Using Computational and Mechanical Models to Study Animal Locomotion

    Science.gov (United States)

    Miller, Laura A.; Goldman, Daniel I.; Hedrick, Tyson L.; Tytell, Eric D.; Wang, Z. Jane; Yen, Jeannette; Alben, Silas

    2012-01-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms’ performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: “Integrating living and physical systems.” PMID:22988026

  6. MTU locomotive drive systems for EU emissions stage IIIB

    Energy Technology Data Exchange (ETDEWEB)

    Wintruff, Ingo [MTU Friedrichshafen GmbH, Friedrichshafen (Germany)

    2011-05-15

    Emissions limits for diesel locomotives within the European Union are regulated by EU Non-road Directive 97/68/EC which places restrictions on the pollutants NOx, particulate, CO and HC. MTU has developed suitable diesel engines for EU Emissions stage IIIB. (orig.)

  7. Energy Efficiency of Robot Locomotion Increases Proportional to Weight

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian; Støy, Kasper

    2011-01-01

    The task of producing steady, stable and energy efficient locomotion in legged robots with the ability to walk in un- known terrain have for many years been a big challenge in robotics. This work is focusing on how different robots build from the modular robotic system, LocoKit by Larsen et. la [3...

  8. Application of flywheel energy storage for heavy haul locomotives

    International Nuclear Information System (INIS)

    Spiryagin, Maksym; Wolfs, Peter; Szanto, Frank; Sun, Yan Quan; Cole, Colin; Nielsen, Dwayne

    2015-01-01

    Highlights: • A novel design for heavy haul locomotive equipped with a flywheel energy storage system is proposed. • The integrated intelligent traction control system was developed. • A flywheel energy storage system has been tested through a simulation process. • The developed hybrid system was verified using an existing heavy haul railway route. • Fuel efficiency analysis confirms advantages of the hybrid design. - Abstract: At the present time, trains in heavy haul operations are typically hauled by several diesel-electric locomotives coupled in a multiple unit. This paper studies the case of a typical consist of three Co–Co diesel-electric locomotives, and considers replacing one unit with an alternative version, with the same design parameters, except that the diesel-electric plant is replaced with flywheel energy storage equipment. The intelligent traction and energy control system installed in this unit is integrated into the multiple-unit control to allow redistribution of the power between all units. In order to verify the proposed design, a three-stage investigation has been performed as described in this paper. The initial stage studies a possible configuration of the flywheel energy storage system by detailed modelling of the proposed intelligent traction and energy control system. The second stage includes the investigation and estimation of possible energy flows using a longitudinal train dynamics simulation. The final stage compares the conventional and the proposed locomotive configurations considering two parameters: fuel efficiency and emissions reduction.

  9. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In our first article on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find…

  10. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In the second paper of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod…

  11. Energy Efficiency of Robot Locomotion Increases Proportional to Weight

    DEFF Research Database (Denmark)

    Larsen, J. C.; Stoy, K.

    2011-01-01

    The task of producing steady, stable and energy efficient locomotion in legged robots with the ability to walk in unknown terrain have for many years been a big challenge in robotics. This work is focusing on how different robots build from the modular robotic system, LocoKit by Larsen et al. [1...

  12. Locomotion and basicranial anatomy in primates and marsupials.

    Science.gov (United States)

    Villamil, Catalina I

    2017-10-01

    There is ongoing debate in paleoanthropology about whether and how the anatomy of the cranium, and especially the cranial base, is evolving in response to locomotor and postural changes. However, the majority of studies focus on two-dimensional data, which fails to capture the complexity of cranial anatomy. This study tests whether three-dimensional cranial base anatomy is linked to locomotion or to other factors in primates (n = 473) and marsupials (n = 231). Results indicate that although there is a small effect of locomotion on cranial base anatomy in primates, this is not the case in marsupials. Instead, facial anatomy likely drives variation in cranial base anatomy in both primates and marsupials, with additional roles for body size and brain size. Although some changes to foramen magnum position and orientation are phylogenetically useful among the hominoids, they do not necessarily reflect locomotion or positional behavior. The interplay between locomotion, posture, and facial anatomy in primates requires further investigation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Decoding bipedal locomotion from the rat sensorimotor cortex

    NARCIS (Netherlands)

    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-01-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower

  14. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  15. Manually operated coded switch

    International Nuclear Information System (INIS)

    Barnette, J.H.

    1978-01-01

    The disclosure related to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made

  16. Switch on, switch off: stiction in nanoelectromechanical switches

    KAUST Repository

    Wagner, Till J W

    2013-06-13

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  17. Avalanche photoconductive switching

    Science.gov (United States)

    Pocha, M. D.; Druce, R. L.; Wilson, M. J.; Hofer, W. W.

    This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV to 35 kV and rise times of 300 to 500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10(exp 3) to over 10(exp 5). Switches with two very different physical configurations and with two different illumination wavelengths (1.06 micrometer, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation.

  18. Avalanche photoconductive switching

    Energy Technology Data Exchange (ETDEWEB)

    Pocha, M.D.; Druce, R.L.; Wilson, M.J.; Hofer, W.W.

    1989-01-01

    This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV--35 kV and rise times of 300--500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10{sup 3} to over 10{sup 5}. Switches with two very different physical configurations and with two different illumination wavelengths (1.06 {mu}m, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation. 3 refs., 6 figs.

  19. Origami-based earthworm-like locomotion robots.

    Science.gov (United States)

    Fang, Hongbin; Zhang, Yetong; Wang, K W

    2017-10-16

    Inspired by the morphology characteristics of the earthworms and the excellent deformability of origami structures, this research creates a novel earthworm-like locomotion robot through exploiting the origami techniques. In this innovation, appropriate actuation mechanisms are incorporated with origami ball structures into the earthworm-like robot 'body', and the earthworm's locomotion mechanism is mimicked to develop a gait generator as the robot 'centralized controller'. The origami ball, which is a periodic repetition of waterbomb units, could output significant bidirectional (axial and radial) deformations in an antagonistic way similar to the earthworm's body segment. Such bidirectional deformability can be strategically programmed by designing the number of constituent units. Experiments also indicate that the origami ball possesses two outstanding mechanical properties that are beneficial to robot development: one is the structural multistability in the axil direction that could contribute to the robot control implementation; and the other is the structural compliance in the radial direction that would increase the robot robustness and applicability. To validate the origami-based innovation, this research designs and constructs three robot segments based on different axial actuators: DC-motor, shape-memory-alloy springs, and pneumatic balloon. Performance evaluations reveal their merits and limitations, and to prove the concept, the DC-motor actuation is selected for building a six-segment robot prototype. Learning from earthworms' fundamental locomotion mechanism-retrograde peristalsis wave, seven gaits are automatically generated; controlled by which, the robot could achieve effective locomotion with qualitatively different modes and a wide range of average speeds. The outcomes of this research could lead to the development of origami locomotion robots with low fabrication costs, high customizability, light weight, good scalability, and excellent re-configurability.

  20. ANALYSIS OF THE OPERATIONAL CHARACTERISTICS OF DIESEL-ELECTRIC LOCOMOTIVES

    Directory of Open Access Journals (Sweden)

    L. V. Ursulyak

    2014-12-01

    Full Text Available Purpose. To compare the operational characteristics of freight diesel-electric locomotives ER20CF and 2М62м, which are operated with Lithuanian Railways. Important problems on traction calculations are considered in this article. In this article the critical tasks of traction calculations are solved. It is the main computational tool in the rational functioning, planning and development of railways: determination of the estimated weight of the rolling stock, the diagrams construction of specific resultant forces of a train, the permitted speed definition of the train on the slopes, curves of train traffic construction on the section. Methodology. Using the rules and methods of traction calculations the analysis of the basic operational characteristics of the modernized freight diesel-electric locomotive 2М62m and freight passenger dual locomotive 2ER20CF was held. The maximum weight of the train set, the track structure on a high-speed ascent through the use of kinetic energy (with traction and without traction, technical speed, acceleration force and the value of the smallest radius curve are selected as controlled parameters. During the calculations it was considered that the trains were formed of a fully loaded four-axle gondola cars, model 112-119 (feature-606 with axle load of 23.5 t; the motion was carried out on the continuous welded rail track; the front of the train set is a dual locomotive 2ER20CF or two locomotive 2М62м. Longitudinal profile of the road on the route Vilnus–KlF was analyzed for the choice of theoretical rise. Inspection concerning the possibility of overcoming the high-speed rise was performed with an analytical method, based on the use of the kinetic energy accumulated by the overcoming of «light» elements of the profile. Findings. In the calculations, the maximum weight of the train set taking into account theoretical rise was analyzed. The inspection of the theoretical weight of the train set on a reliable

  1. Spatially Compact Neural Clusters in the Dorsal Striatum Encode Locomotion Relevant Information.

    Science.gov (United States)

    Barbera, Giovanni; Liang, Bo; Zhang, Lifeng; Gerfen, Charles R; Culurciello, Eugenio; Chen, Rong; Li, Yun; Lin, Da-Ting

    2016-10-05

    An influential striatal model postulates that neural activities in the striatal direct and indirect pathways promote and inhibit movement, respectively. Normal behavior requires coordinated activity in the direct pathway to facilitate intended locomotion and indirect pathway to inhibit unwanted locomotion. In this striatal model, neuronal population activity is assumed to encode locomotion relevant information. Here, we propose a novel encoding mechanism for the dorsal striatum. We identified spatially compact neural clusters in both the direct and indirect pathways. Detailed characterization revealed similar cluster organization between the direct and indirect pathways, and cluster activities from both pathways were correlated with mouse locomotion velocities. Using machine-learning algorithms, cluster activities could be used to decode locomotion relevant behavioral states and locomotion velocity. We propose that neural clusters in the dorsal striatum encode locomotion relevant information and that coordinated activities of direct and indirect pathway neural clusters are required for normal striatal controlled behavior. VIDEO ABSTRACT. Published by Elsevier Inc.

  2. Energy-based control for a biologically inspired hexapod robot with rolling locomotion

    Directory of Open Access Journals (Sweden)

    Takuma Nemoto

    2015-04-01

    Full Text Available This paper presents an approach to control rolling locomotion on the level ground with a biologically inspired hexapod robot. For controlling rolling locomotion, a controller which can compensate energy loss with rolling locomotion of the hexapod robot is designed based on its dynamic model. The dynamic model describes the rolling locomotion which is limited to planar one by an assumption that the hexapod robot does not fall down while rolling and influences due to collision and contact with the ground, and it is applied for computing the mechanical energy of the hexapod robot and a plant for a numerical simulation. The numerical simulation of the rolling locomotion on the level ground verifies the effectiveness of the proposed controller. The simulation results show that the hexapod robot can perform the rolling locomotion with the proposed controller. In conclusion, it is shown that the proposed control approach is effective in achieving the rolling locomotion on the level ground.

  3. Energy losses in switches

    International Nuclear Information System (INIS)

    Martin, T.H.; Seamen, J.F.; Jobe, D.O.

    1993-01-01

    The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF 6 polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V peak I peak ) 1.1846 . When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset

  4. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  5. Electromechanical magnetization switching

    International Nuclear Information System (INIS)

    Chudnovsky, Eugene M.; Jaafar, Reem

    2015-01-01

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

  6. JUNOS Enterprise Switching

    CERN Document Server

    Reynolds, Harry

    2009-01-01

    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  7. Switch mode power supply

    International Nuclear Information System (INIS)

    Kim, Hui Jun

    1993-06-01

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  8. The coal-fired gas turbine locomotive - A new look

    Science.gov (United States)

    Liddle, S. G.; Bonzo, B. B.; Purohit, G. P.

    1983-01-01

    Advances in turbomachine technology and novel methods of coal combustion may have made possible the development of a competitive coal fired gas turbine locomotive engine. Of the combustor, thermodynamic cycle, and turbine combinations presently assessed, an external combustion closed cycle regenerative gas turbine with a fluidized bed coal combustor is judged to be the best suited for locomotive requirements. Some merit is also discerned in external combustion open cycle regenerative systems and internal combustion open cycle regenerative gas turbine systems employing a coal gasifier. The choice of an open or closed cycle depends on the selection of a working fluid and the relative advantages of loop pressurization, with air being the most attractive closed cycle working fluid on the basis of cost.

  9. The Perceived Naturalness of Virtual Walking Speeds during WIP Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    It is well established that individuals tend to underestimate visually presented walking speeds when relying on treadmills for virtual walking. However, prior to the present studies this perceptual distortion had not been observed in relation to Walking-in-Place (WIP) locomotion, and a number...... to how gait cycle characteristics, visual display properties, and methodological differences affect speed underestimation during treadmill and WIP locomotion. The studies suggested the following: A significant main effect was found for step frequency; both display and geometric field of view were...... inversely proportional to the degree of underestimation; varying degrees of peripheral occlusion and increased HMD weight did not yield significant main effects; and the choice of method (i.e., how the speeds were presented) had a significant effect on the upper and lower bounds of what speeds were...

  10. Nonlinear control methods for planar carangiform robot fish locomotion

    OpenAIRE

    Morgansen, Kristi A.; Duindam, Vincent; Mason, Richard J.; Burdick, Joel W.; Murray, Richard M.

    2001-01-01

    Considers the design of motion control algorithms for robot fish. We present modeling, control design, and experimental trajectory tracking results for an experimental planar robotic fish system that is propelled using carangiform-like locomotion. Our model for the fish's propulsion is based on quasi-steady fluid flow. Using this model, we propose gaits for forward and turning trajectories and analyze system response under such control strategies. Our models and predictions are verified by ex...

  11. Performance analysis of jump-gliding locomotion for miniature robotics.

    Science.gov (United States)

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-03-26

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.

  12. Using Computational and Mechanical Models to Study Animal Locomotion

    OpenAIRE

    Miller, Laura A.; Goldman, Daniel I.; Hedrick, Tyson L.; Tytell, Eric D.; Wang, Z. Jane; Yen, Jeannette; Alben, Silas

    2012-01-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms’ performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locom...

  13. Markerless 3D motion capture for animal locomotion studies

    OpenAIRE

    William Irvin Sellers; Eishi Hirasaki

    2014-01-01

    ABSTRACT Obtaining quantitative data describing the movements of animals is an essential step in understanding their locomotor biology. Outside the laboratory, measuring animal locomotion often relies on video-based approaches and analysis is hampered because of difficulties in calibration and often the limited availability of possible camera positions. It is also usually restricted to two dimensions, which is often an undesirable over-simplification given the essentially three-dimensional na...

  14. Improved Usability of Locomotion Devices Using Human-Centric Taxonomy

    Science.gov (United States)

    2009-03-01

    the classification of interaction devices by the limbs used in the interaction rather than by arbitrary classifications, such as “ wand ”, or “glove...ABILITY REQUIREMENTS ANALYSIS USING F-JAS In Tables 5 through 8, we took the results of a sample HAR analysis done by Cockayne and Darken [13] comparing...point less than natural locomotion in all categories except for explosive strength, in which it receives 2 less points. 2. Decelerate from Walk or Jog

  15. Sustained periodic terrestrial locomotion in air-breathing fishes.

    Science.gov (United States)

    Pace, C M; Gibb, A C

    2014-03-01

    While emergent behaviours have long been reported for air-breathing osteichthyians, only recently have researchers undertaken quantitative analyses of terrestrial locomotion. This review summarizes studies of sustained periodic terrestrial movements by air-breathing fishes and quantifies the contributions of the paired appendages and the axial body to forward propulsion. Elongate fishes with axial-based locomotion, e.g. the ropefish Erpetoichthys calabaricus, generate an anterior-to-posterior wave of undulation that travels down the axial musculoskeletal system and pushes the body against the substratum at multiple points. In contrast, appendage-based locomotors, e.g. the barred mudskipper Periophthalmus argentilineatus, produce no axial bending during sustained locomotion, but instead use repeated protraction-retraction cycles of the pectoral fins to elevate the centre of mass and propel the entire body anteriorly. Fishes that use an axial-appendage-based mechanism, e.g. walking catfishes Clarias spp., produce side-to-side, whole-body bending in co-ordination with protraction-retraction cycles of the pectoral fins. Once the body is maximally bent to one side, the tail is pressed against the substratum and drawn back through the mid-sagittal plane, which elevates the centre of mass and rotates it about a fulcrum formed by the pectoral fin and the ground. Although appendage-based terrestrial locomotion appears to be rare in osteichthyians, many different species appear to have converged upon functionally similar axial-based and axial-appendage-based movements. Based on common forms observed across divergent taxa, it appears that dorsoventral compression of the body, elongation of the axial skeleton or the presence of robust pectoral fins can facilitate effective terrestrial movement by air-breathing fishes. © 2014 The Fisheries Society of the British Isles.

  16. The role of vortices in animal locomotion in fluids

    Directory of Open Access Journals (Sweden)

    Dvořák R.

    2014-12-01

    Full Text Available The aim of this paper is to show the significance of vortices in animal locomotion in fluids on two deliberately chosen examples. The first example concerns lift generation by bird and insect wings, the second example briefly mentiones swimming and walking on water. In all the examples, the vortices generated by the moving animal impart the necessary momentum to the surrounding fluid, the reaction to which is the force moving or lifting the animal.

  17. Equilibrium Condition during Locomotion and Gait in Broiler Chickens

    Directory of Open Access Journals (Sweden)

    MCF Alves

    Full Text Available ABSTRACT The experiment was carried out with the objective of evaluating a methodology to estimate the angulation and equilibrium condition, relating them to gait score and the main diseases of the locomotion system in males and females of commercial broiler strains. A completely randomized experimental design in a factorial arrangement (2x2 was applied, consisting of two sexes and two genetic strains, with five replicates of 53 chickens each. The following characteristics related to broiler locomotion were studied: gait score (GS; incidence of Valgus (VAL and Varus (VAR deformities and of pododermatitis (POD; body angle relative the ground (ANG; equilibrium condition (EC; body weight (BW and breast weight (BrW; and incidence of femoral degeneration (FD, tibial dyschondroplasia (TD and spondylolisthesis (SPO. GS, and VAL and VAR were assessed inside a broiler house. Birds were then photographed to estimate ANG and EC. Birds were sacrificed at 42 days of age and analyzed for FD, TD, and SPO. Breast percentage was not influenced by sex or strain. Males showed better ANG than females, regardless of strain. Overall, the strains studied showed prostrated EC. The correlation between GS and the evaluated traits was low. There was a moderate to high association between EC and ANG both in males and females. GS showed low correlation with locomotion problems, and therefore, it is a poor indicator of skeletal diseases. On the other hand, the moderate to high correlations of ANG and EC with locomotion problems make them better indicators of bone diseases than gait score, which is possibly more related to EC and body posture than to bone pathologies.

  18. Locomotion of Stramonita haemastoma (Linnaeus (Gastropoda, Muricidae on a mixed shore of rocks and sand

    Directory of Open Access Journals (Sweden)

    Marcos G. Papp

    2001-03-01

    Full Text Available Mixed shores of rocks and sand are appropriate systems for the study of limitations that the isolation of rocks may impose for gastropods that typically inhabit rocky shores. We marked 52 Stramonita haemastoma (Linnaeus, 1767 snails on a mixed shore and found that 34 of them moved between rocks one to four times during 15 surveys in a period of 72 days. In the experiments, the snails moved on rock by continuous, direct, ditaxic, alternate undulations of the foot sole but on submerged sand they used slower arrhythmic discontinuous contractions of the foot sole. They switched between modes of locomotion in response to the type and topography of the substrate and possibly to water dynamics. In nature, snails moved between rocks forming aggregations where they oviposited. This may have masked other causes of movement, such as availability of prey. Most snails burrowed into the sand when the rocks became exposed during low tides. Further experiments are needed to explicitly address the possible causes of movements among rocks and burial.

  19. PDGF controls contact inhibition of locomotion by regulating N-cadherin during neural crest migration.

    Science.gov (United States)

    Bahm, Isabel; Barriga, Elias H; Frolov, Antonina; Theveneau, Eric; Frankel, Paul; Mayor, Roberto

    2017-07-01

    A fundamental property of neural crest (NC) migration is contact inhibition of locomotion (CIL), a process by which cells change their direction of migration upon cell contact. CIL has been proven to be essential for NC migration in amphibians and zebrafish by controlling cell polarity in a cell contact-dependent manner. Cell contact during CIL requires the participation of the cell adhesion molecule N-cadherin, which starts to be expressed by NC cells as a consequence of the switch between E- and N-cadherins during epithelial-to-mesenchymal transition (EMT). However, the mechanism that controls the upregulation of N-cadherin remains unknown. Here, we show that platelet-derived growth factor receptor alpha (PDGFRα) and its ligand platelet-derived growth factor A (PDGF-A) are co-expressed in migrating cranial NC. Inhibition of PDGF-A/PDGFRα blocks NC migration by inhibiting N-cadherin and, consequently, impairing CIL. Moreover, we identify phosphatidylinositol-3-kinase (PI3K)/AKT as a downstream effector of the PDGFRα cellular response during CIL. Our results lead us to propose PDGF-A/PDGFRα signalling as a tissue-autonomous regulator of CIL by controlling N-cadherin upregulation during EMT. Finally, we show that once NC cells have undergone EMT, the same PDGF-A/PDGFRα works as an NC chemoattractant, guiding their directional migration. © 2017. Published by The Company of Biologists Ltd.

  20. Full-scale locomotive dynamic crash testing and correlations : locomotive consist colliding with steel coil truck at grade crossing (test 3).

    Science.gov (United States)

    2011-09-01

    This report presents the test results and finite element correlations of a full-scale dynamic collision between a locomotive and a highway truck loaded with two heavy steel coils. The locomotive consist was moving at 58 miles per hour before it struc...

  1. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  2. Control method for biped locomotion robots based on ZMP information

    International Nuclear Information System (INIS)

    Kume, Etsuo

    1994-01-01

    The Human Acts Simulation Program (HASP) started as a ten year program of Computing and Information Systems Center (CISC) at Japan Atomic Energy Research Institute (JAERI) in 1987. A mechanical design study of biped locomotion robots for patrol and inspection in nuclear facilities is being performed as an item of the research scope. One of the goals of our research is to design a biped locomotion robot for practical use in nuclear facilities. So far, we have been studying for several dynamic walking patterns. In conventional control methods for biped locomotion robots, the program control is used based on preset walking patterns, so it dose not have the robustness such as a dynamic change of walking pattern. Therefore, a real-time control method based on dynamic information of the robot states is necessary for the high performance of walking. In this study a new control method based on Zero Moment Point (ZMP) information is proposed as one of real-time control methods. The proposed method is discussed and validated based on the numerical simulation. (author)

  3. The aspect of vector control using the asynchronous traction motor in locomotives

    Directory of Open Access Journals (Sweden)

    L. Liudvinavičius

    2009-12-01

    Full Text Available The article examines curves controlling asynchronous traction motors increasingly used in locomotive electric drives the main task of which is to create a tractive effort-speed curve of an ideal locomotive Fk = f(v, including a hyperbolic area the curve of which will create conditions showing that energy created by the diesel engine of diesel locomotives (electric locomotives and in case of electric trains, electricity taken from the contact network over the entire range of locomotive speed is turned into efficient work. Mechanical power on wheel sets is constant Pk = Fkv = const, the power of the diesel engine is fully used over the entire range of locomotive speed. Tractive effort-speed curve Fk(v shows the dependency of locomotive traction power Fk on movement speed v. The article presents theoretical and practical aspects relevant to creating the structure of locomotive electric drive and selecting optimal control that is especially relevant to creating the structure of locomotive electric drive using ATM (asynchronous traction motor that gains special popularity in traction rolling stock replacing DC traction motors having low reliability. The frequency modes of asynchronous motor speed regulation are examined. To control ATM, the authors suggest the method of vector control presenting the structural schemes of a locomotive with ATM and control algorithm.

  4. Locomotion training of legged robots using hybrid machine learning techniques

    Science.gov (United States)

    Simon, William E.; Doerschuk, Peggy I.; Zhang, Wen-Ran; Li, Andrew L.

    1995-01-01

    In this study artificial neural networks and fuzzy logic are used to control the jumping behavior of a three-link uniped robot. The biped locomotion control problem is an increment of the uniped locomotion control. Study of legged locomotion dynamics indicates that a hierarchical controller is required to control the behavior of a legged robot. A structured control strategy is suggested which includes navigator, motion planner, biped coordinator and uniped controllers. A three-link uniped robot simulation is developed to be used as the plant. Neurocontrollers were trained both online and offline. In the case of on-line training, a reinforcement learning technique was used to train the neurocontroller to make the robot jump to a specified height. After several hundred iterations of training, the plant output achieved an accuracy of 7.4%. However, when jump distance and body angular momentum were also included in the control objectives, training time became impractically long. In the case of off-line training, a three-layered backpropagation (BP) network was first used with three inputs, three outputs and 15 to 40 hidden nodes. Pre-generated data were presented to the network with a learning rate as low as 0.003 in order to reach convergence. The low learning rate required for convergence resulted in a very slow training process which took weeks to learn 460 examples. After training, performance of the neurocontroller was rather poor. Consequently, the BP network was replaced by a Cerebeller Model Articulation Controller (CMAC) network. Subsequent experiments described in this document show that the CMAC network is more suitable to the solution of uniped locomotion control problems in terms of both learning efficiency and performance. A new approach is introduced in this report, viz., a self-organizing multiagent cerebeller model for fuzzy-neural control of uniped locomotion is suggested to improve training efficiency. This is currently being evaluated for a possible

  5. Association of Mode of Locomotion and Independence in Locomotion With Long-Term Outcomes After Spinal Cord Injury

    Science.gov (United States)

    Krause, James; Carter, Rickey E; Brotherton, Sandra

    2009-01-01

    Background/Objective: To explore the association of mode of locomotion (ambulation vs wheelchair use) and independence in locomotion (independent vs require assistance) with health, participation, and subjective well-being (SWB) after spinal cord injury (SCI). Research Design: Secondary analysis was conducted on survey data collected from 2 rehabilitation hospitals in the Midwest and a specialty hospital in the southeastern United States. The 1,493 participants were a minimum of 18 years of age and had traumatic SCI of at least 1 year duration at enrollment. Main Outcome Measures: Three sets of outcome measures were used: SWB, participation, and health. SWB was measured by 8 scales and a measure of depressive symptoms, participation by 3 items, health by general health ratings, days in poor health, hospitalizations, and treatments. Results: Small but significant associations were observed between independence in locomotion and every outcome. Ambulation was associated with greater participation but a mixed pattern of favorable and unfavorable health and SWB outcomes. Supplemental analyses were conducted on those who ambulated but who were dependent on others to do so (n = 117), because this group reported poor outcomes in several areas. Individuals who were independent in wheelchair use reported substantially better outcomes than nonwheelchair users and those dependent on others in wheelchair use. Conclusions: Although ambulation is often a recovery goal, individuals with SCI who ambulate do not uniformly report better outcomes than wheelchair users, and those who depend on others for assistance with ambulation may experience a unique set of problems. PMID:19810625

  6. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young's modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young's modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  7. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  8. Motorneurons dedicated to either forward or backward locomotion in the nematode C. elegans

    OpenAIRE

    Haspel, Gal; O'Donovan, Michael J.; Hart, Anne C.

    2010-01-01

    Multifunctional motorneurons and muscles, which are active during forward and backward locomotion and driven by common central pattern generators, are ubiquitous in animal models. However, studies in the nematode Caenorhabditis elegans suggest that some locomotor motorneurons are necessary only for forward locomotion (dorsal B-motorneurons, DB) while others (dorsal A-motorneurons, DA) are necessary only for backward locomotion. We tested this hypothesis directly by recording the activity of t...

  9. Optical computer switching network

    Science.gov (United States)

    Clymer, B.; Collins, S. A., Jr.

    1985-01-01

    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  10. On designing geometric motion planners to solve regulating and trajectory tracking problems for robotic locomotion systems

    International Nuclear Information System (INIS)

    Asnafi, Alireza; Mahzoon, Mojtaba

    2011-01-01

    Based on a geometric fiber bundle structure, a generalized method to solve both regulation and trajectory tracking problems for locomotion systems is presented. The method is especially applied to two case studies of robotic locomotion systems; a three link articulated fish-like robot as a prototype of locomotion systems with symmetry, and the snakeboard as a prototype of mixed locomotion systems. Our results show that although these motion planners have an open loop structure, due to their generalities, they can steer case studies with negligible errors for almost any complicated path.

  11. On designing geometric motion planners to solve regulating and trajectory tracking problems for robotic locomotion systems

    Energy Technology Data Exchange (ETDEWEB)

    Asnafi, Alireza [Hydro-Aeronautical Research Center, Shiraz University, Shiraz, 71348-13668 (Iran, Islamic Republic of); Mahzoon, Mojtaba [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz, 71348-13668 (Iran, Islamic Republic of)

    2011-09-15

    Based on a geometric fiber bundle structure, a generalized method to solve both regulation and trajectory tracking problems for locomotion systems is presented. The method is especially applied to two case studies of robotic locomotion systems; a three link articulated fish-like robot as a prototype of locomotion systems with symmetry, and the snakeboard as a prototype of mixed locomotion systems. Our results show that although these motion planners have an open loop structure, due to their generalities, they can steer case studies with negligible errors for almost any complicated path.

  12. INFLUENCE OF ROLLING STOCK VIBROACOUSTICAL PARAMETERS ON THE CHOICE OF RATIONAL VALUES OF LOCOMOTIVE RUNNING GEAR

    Directory of Open Access Journals (Sweden)

    Yu. V. Zelenko

    2016-06-01

    Full Text Available Purpose.The success of the traffic on the railways of Ukraine depends on the number and the operational fleet of electric locomotives. Today, the locomotive depot exploit physically and morally outdated locomotives that have low reliability. Modernization of electric locomotives is not economically justified. The aim of this study is to improve the safety of the traction rolling stock by the frequency analysis of dynamical systems, which allows conducting the calculation of the natural (of resonant frequencies of the design and related forms of vibrations.Methodology.The study was conducted by methods of analytical mechanics and mathematical modeling of operating loads of freight locomotive when driving at different speeds on the straight and curved track sections. The theoretical value of the work is the technique of choice of constructive schemes and rational parameters of perspective electric locomotive taking into account the electric inertia ratios and stiffness coefficients of Lagrange second-order equations.Findings. The problems of theoretical research and the development of a mathematical model of the spatial electric vibrations are solved. The theoretical studies of the effect of inertia ratios and stiffness coefficients on the dynamic values and the parameter values of electric locomotive undercarriages are presented.Originality.The set of developed regulations and obtained results is a practical solution to selecting rational parameters of bogies of the freight mainline locomotive for railways of Ukraine. A concept of choice of constructive scheme and rational parameters of perspective locomotive is formulated. It is developed the method of calculation of spatial electric locomotive oscillations to determine its dynamic performance. The software complex for processing the data of experimental studies of dynamic parameters of electric locomotive and comparing the results of the theoretical calculations with the data of full

  13. Stochastic Switching Dynamics

    DEFF Research Database (Denmark)

    Simonsen, Maria

    This thesis treats stochastic systems with switching dynamics. Models with these characteristics are studied from several perspectives. Initially in a simple framework given in the form of stochastic differential equations and, later, in an extended form which fits into the framework of sliding...... mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

  14. Very high plasma switches. Basic plasma physics and switch technology

    International Nuclear Information System (INIS)

    Doucet, H.J.; Roche, M.; Buzzi, J.M.

    1988-01-01

    A review of some high power switches recently developed for very high power technology is made with a special attention to the aspects of plasma physics involved in the mechanisms, which determine the limits of the possible switching parameters

  15. Support afferentation in the posture and locomotion control system

    Science.gov (United States)

    Grigoriev, Anatoly; Tomilovskaya, Elena; Kozlovskaya, Inesa

    Mechanisms of support afferentation contribution in posture and locomotion control, which were uncertain up to now, became the point of intensive studies recently. This became possible since the space flights era started which created the conditions for simulated microgravity experiments under conditions of dry immersion and bedrest. The results of neurophysiological studies performed under the conditions of supportlessness have shown that decline or elimination of support loads is followed by deep and fast developing alterations in postural tonic system, including development of postural muscle atonia, changes of recruitment order of motoneurons innervating the shin muscles, spinal hyperreflexia development etc. (Kozlovskaya I.B. et al., 1987). It has been also shown that application of artificial support stimulation in the regimen of natural locomotion under these conditions decreases significantly or even eliminates the development of mentioned changes. The results of these studies laid down the basis for a new hypothesis on the trigger role of support afferentation in postural tonic system and its role in organization and control of postural synergies (Grigoriev A.I. et al., 2004). According to this hypothesis the muscle reception is considered to be the leading afferent input in the control of locomotion. However the data of recent studies pointed out strongly to the participation of support afferentation in definition of cognitive strategies and motor programs of locomotor movements (Chernikova L.A. et al., 2013) and, consequently, in the processes of their initiation (Gerasimenko Yu.P. et al., 2012). The cortical locomotor reflex composes apparently the basis of these processes. The receptive field of this reflex is located in the support zones of the soles and the central part is located in the posterior parietal areas (IPL) of brain cortex. The study is supported by RFBR grant N 13-04-12091 OFI-m.

  16. Sexuality of Disabled Athletes Depending on the Form of Locomotion

    Directory of Open Access Journals (Sweden)

    Plinta Ryszard

    2015-12-01

    Full Text Available The main purpose of this study was to determine sexuality of disabled athletes depending on the form of locomotion. The study included 170 disabled athletes, aged between 18 and 45. The entire population was divided into 3 research groups depending on the form of locomotion: moving on wheelchairs (n=52, on crutches (n=29 and unaided (n=89. The research tool was a questionnaire voluntarily and anonymously completed by the respondents of the research groups. The questionnaire was composed of a general part concerning the socio-demographic conditions, medical history, health problems, a part dedicated to physical disability as well as the Polish version of the International Index of Erectile Function (IIEF and the Female Sexual Function Index (FSFI evaluating sexual life. STATISTICA 10.0 for Windows was used in the statistical analysis. Subjects moving on crutches were significantly older than ones moving on wheelchairs and unaided (34.41 ±11.00 vs. 30.49 ±10.44 and 27.99 ±10.51 years, respectively (p=0.018. Clinically significant erectile dysfunctions were most often diagnosed in athletes moving on wheelchairs (70.27%, followed by athletes moving on crutches and moving unaided (60% and 35.42%, respectively; p=0.048. Clinical sexual dysfunctions were diagnosed on a similar level among all female athletes. It was concluded that the form of locomotion may determine sexuality of disabled men. Males on wheelchair revealed the worst sexual functioning. Female athletes moving on wheelchairs, on crutches and moving unaided were comparable in the aspect of their sexual life.

  17. Biomechanical Analysis of Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    De Witt, J. K.; Fincke, R. S.; Guilliams, M. E.; Ploutz-Snyder, L. L.

    2011-01-01

    Treadmill locomotion exercise is an important aspect of ISS exercise countermeasures. It is widely believed that an optimized treadmill exercise protocol could offer benefits to cardiovascular and bone health. If training heart rate is high enough, treadmill exercise is expected to lead to improvements in aerobic fitness. If impact or bone loading forces are high enough, treadmill exercise may be expected to contribute to improved bone outcomes. Ground-based research suggests that joint loads increase with increased running speed. However, it is unknown if increases in locomotion speed results in similar increases in joint loads in microgravity. Although data exist regarding the biomechanics of running and walking in microgravity, a majority were collected during parabolic flight or during investigations utilizing a microgravity analog. The Second Generation Treadmill (T2) has been in use on the International Space Station (ISS) and records the ground reaction forces (GRF) produced by crewmembers during exercise. Biomechanical analyses will aid in understanding potential differences in typical gait motion and allow for modeling of the human body to determine joint and muscle forces during exercise. By understanding these mechanisms, more appropriate exercise prescriptions can be developed that address deficiencies. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine how combinations of subject load and speed influence joint loading during in-flight treadmill exercise. Further, the data will be used to characterize any differences in specific bone and muscle loading during locomotion in these two gravitational conditions. This project maps to the HRP Integrated Research Plan risks including Risk of Bone Fracture (Gap B15), Risk of Early Onset Osteoporosis Due to

  18. Biodiesel fuel costs and environmental issues when powering railway locomotives

    Energy Technology Data Exchange (ETDEWEB)

    Mirza, Abdul; Ziemer, Norbert; Tatara, Robert; Moraga, Reinaldo; Mirman, Clifford; Vohra, Promod

    2010-09-15

    Issues for adopting biodiesel fuel, instead of petrodiesel, to power railroad locomotives are engine performance and emissions, fuel infrastructure, and fuel cost. These are evaluated for B2 through B100 blends. Biodiesel's solvent action on fuel systems is addressed. With biodiesel, hydrocarbon, carbon monoxide, and particulate emissions are unchanged or reduced. Nitrogen oxides are elevated but it is believed that engine alterations can minimize these emissions. A Transportation Model, using data from a major railway, has demonstrated that refueling depots can be fully supplied with biodiesel at a pricing premium of 1% to 26%, depending on blend and geographical location.

  19. Human-robot interaction strategies for walker-assisted locomotion

    CERN Document Server

    Cifuentes, Carlos A

    2016-01-01

    This book presents the development of a new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation. The aim is to achieve a closer interaction between the robotic device and the individual, empowering the rehabilitation potential of such devices in clinical applications. A new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation is presented. Trends and opportunities for future advances in the field of assistive locomotion via the development of hybrid solutions based on the combination of smart walkers and biomechatronic exoskeletons are also discussed. .

  20. Optimization of the Hood of Diesel Electric Locomotive

    Directory of Open Access Journals (Sweden)

    Petr TOMEK

    2013-06-01

    Full Text Available The new construction of hood of diesel electric locomotive is analyzed in this paper. The whole construction is loaded by inertia effects caused by prescribed acceleration. The parts of the hood are subject to the standards for railway applications CSN EN 12663-1 [1]. Numerical analyses are performed by FEM computer program COSMOSWorks [2]. The original construction of hood is analyzed in first part of this paper. Structural changes are proposed in the next part of this article. Carrying capacity of the new construction of hood is verified by a numerical analysis. The results of the new construction are compared with the original construction of hood.

  1. Improvement of fuel injection system of locomotive diesel engine.

    Science.gov (United States)

    Li, Minghai; Cui, Hongjiang; Wang, Juan; Guan, Ying

    2009-01-01

    The traditional locomotive diesels are usually designed for the performance of rated condition and much fuel will be consumed. A new plunger piston matching parts of fuel injection pump and injector nozzle matching parts were designed. The experimental results of fuel injection pump test and diesel engine show that the fuel consumption rate can be decreased a lot in the most of the working conditions. The forced lubrication is adopted for the new injector nozzle matching parts, which can reduce failure rate and increase service life. The design has been patented by Chinese State Patent Office.

  2. Ultrafast gas switching experiments

    International Nuclear Information System (INIS)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1993-01-01

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes Khz at > 100 kV/m E field

  3. An integrated circuit switch

    Science.gov (United States)

    Bonin, E. L.

    1969-01-01

    Multi-chip integrated circuit switch consists of a GaAs photon-emitting diode in close proximity with S1 phototransistor. A high current gain is obtained when the transistor has a high forward common-emitter current gain.

  4. The Octopus switch

    NARCIS (Netherlands)

    Havinga, Paul J.M.

    2000-01-01

    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a

  5. Untriggered water switching

    International Nuclear Information System (INIS)

    Van Devender, J.P.; Martin, T.H.

    Recent experiments indicate that synchronous untriggered multichannel switching in water will permit the development of relatively simple, ultra-low impedance, short pulse, relativistic electron beam (REB) accelerators. These experiments resulted in the delivery of a 1.5 MV, 0.75 MA, 15 ns pulse into a two-ohm line with a current risetime of 2 x 10 14 A/sec. The apparatus consisted of a 3 MV Marx generator and a series of three 112 cm wide strip water lines separated by two edge-plane water-gap switches. The Marx generator charged the first line in less than 400 ns. The first switch then formed five or more channels. The second line was charged in 60 ns and broke down with 10 to 25 channels at a mean field of 1.6 MV/cm. The closure time of each spark channel along both switches was measured with a streak camera and showed low jitter. The resulting fast pulse line construction is simpler and should provide considerable costs savings from previous designs. Multiples of these low impedance lines in parallel can be employed to obtain power levels in the 10 14 W range for REB fusion studies. (U.S.)

  6. Control synthesis of switched systems

    CERN Document Server

    Zhao, Xudong; Niu, Ben; Wu, Tingting

    2017-01-01

    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  7. Full-scale locomotive dynamic collision testing and correlations : offset collisions between a locomotive and a covered hopper car (test 4).

    Science.gov (United States)

    2011-09-01

    This report presents the test results and finite element correlations of a full-scale dynamic collision test with rail vehicles as part of the Federal Railroad Administrations research program on improved crashworthiness of locomotive structures. ...

  8. Contact enhancement of locomotion in spreading cell colonies

    Science.gov (United States)

    D'Alessandro, Joseph; Solon, Alexandre P.; Hayakawa, Yoshinori; Anjard, Christophe; Detcheverry, François; Rieu, Jean-Paul; Rivière, Charlotte

    2017-10-01

    The dispersal of cells from an initially constrained location is a crucial aspect of many physiological phenomena, ranging from morphogenesis to tumour spreading. In such processes, cell-cell interactions may deeply alter the motion of single cells, and in turn the collective dynamics. While contact phenomena like contact inhibition of locomotion are known to come into play at high densities, here we focus on the little explored case of non-cohesive cells at moderate densities. We fully characterize the spreading of micropatterned colonies of Dictyostelium discoideum cells from the complete set of individual trajectories. From data analysis and simulation of an elementary model, we demonstrate that contact interactions act to speed up the early population spreading by promoting individual cells to a state of higher persistence, which constitutes an as-yet unreported contact enhancement of locomotion. Our findings also suggest that the current modelling paradigm of memoryless active particles may need to be extended to account for the history-dependent internal state of motile cells.

  9. Hybrid magnetic mechanism for active locomotion based on inchworm motion

    International Nuclear Information System (INIS)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi

    2013-01-01

    Magnetic robots have been studied in the past. Insect-type micro-robots are used in various biomedical applications; researchers have developed inchworm micro-robots for endoscopic use. A biological inchworm has a looping locomotion gait. However, most inchworm micro-robots depend on a general bending, or bellows, motion. In this paper, we introduce a new robotic mechanism using magnetic force and torque control in a rotating magnetic field for a looping gait. The proposed robot is controlled by the magnetic torque, attractive force, and body mechanisms (two stoppers, flexible body, and different frictional legs). The magnetic torque generates a general bending motion. In addition, the attractive force and body mechanisms produce the robot’s looping motion within a rotating magnetic field and without the use of an algorithm for field control. We verified the device’s performance and analyzed the motion through simulations and various experiments. The robot mechanism can be applied to active locomotion for various medical robots, such as wireless endoscopes. (technical note)

  10. Controlling legs for locomotion-insights from robotics and neurobiology.

    Science.gov (United States)

    Buschmann, Thomas; Ewald, Alexander; von Twickel, Arndt; Büschges, Ansgar

    2015-06-29

    Walking is the most common terrestrial form of locomotion in animals. Its great versatility and flexibility has led to many attempts at building walking machines with similar capabilities. The control of walking is an active research area both in neurobiology and robotics, with a large and growing body of work. This paper gives an overview of the current knowledge on the control of legged locomotion in animals and machines and attempts to give walking control researchers from biology and robotics an overview of the current knowledge in both fields. We try to summarize the knowledge on the neurobiological basis of walking control in animals, emphasizing common principles seen in different species. In a section on walking robots, we review common approaches to walking controller design with a slight emphasis on biped walking control. We show where parallels between robotic and neurobiological walking controllers exist and how robotics and biology may benefit from each other. Finally, we discuss where research in the two fields diverges and suggest ways to bridge these gaps.

  11. Differences in gaze anticipation for locomotion with and without vision

    Science.gov (United States)

    Authié, Colas N.; Hilt, Pauline M.; N'Guyen, Steve; Berthoz, Alain; Bennequin, Daniel

    2015-01-01

    Previous experimental studies have shown a spontaneous anticipation of locomotor trajectory by the head and gaze direction during human locomotion. This anticipatory behavior could serve several functions: an optimal selection of visual information, for instance through landmarks and optic flow, as well as trajectory planning and motor control. This would imply that anticipation remains in darkness but with different characteristics. We asked 10 participants to walk along two predefined complex trajectories (limaçon and figure eight) without any cue on the trajectory to follow. Two visual conditions were used: (i) in light and (ii) in complete darkness with eyes open. The whole body kinematics were recorded by motion capture, along with the participant's right eye movements. We showed that in darkness and in light, horizontal gaze anticipates the orientation of the head which itself anticipates the trajectory direction. However, the horizontal angular anticipation decreases by a half in darkness for both gaze and head. In both visual conditions we observed an eye nystagmus with similar properties (frequency and amplitude). The main difference comes from the fact that in light, there is a shift of the orientations of the eye nystagmus and the head in the direction of the trajectory. These results suggest that a fundamental function of gaze is to represent self motion, stabilize the perception of space during locomotion, and to simulate the future trajectory, regardless of the vision condition. PMID:26106313

  12. Locomotion and Grasping impairment in preschoolers with autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Francesca Fulceri

    2015-08-01

    Full Text Available Objective: To investigate expressiveness of motor impairment in autism spectrum disorder (ASD and its correlation with developmental and clinical features of ASD. Method: Thirty-five male preschoolers with ASD completed the Peabody Developmental Motor Scales-2 (PDMS-2; Folio and Fewell, 2000 and underwent a multidisciplinary assessment including medical examination, standardized assessment of cognitive abilities, administration of Autism_Diagnostic_Observation_Schedule (ADOS and a parent interview about adaptive skills. Results: Results revealed a substantial impairment in locomotion and grasping skills. Both fine and gross motor skills were significantly correlated with non verbal IQ and adaptive behaviours (p<0.01 but not with chronological age or ADOS scores. Children with weaker motor skills have greater cognitive and adaptive behaviours deficits. Conclusions: Motor development in ASD can be detected at preschool age and locomotion and grasping skills are substantially the most impaired area. These findings support the need to assess motor skills in preschoolers with ASD in addition to other developmental skill areas. Along with the increasingly acknowledged importance of motor skills for subsequent social, cognitive, and communicative development our findings support the need to consider motor intervention as a key area in therapeutic program to improve outcome in preschoolers with ASD.

  13. A Reconfigurable Omnidirectional Soft Robot Based on Caterpillar Locomotion.

    Science.gov (United States)

    Zou, Jun; Lin, Yangqiao; Ji, Chen; Yang, Huayong

    2018-04-01

    A pneumatically powered, reconfigurable omnidirectional soft robot based on caterpillar locomotion is described. The robot is composed of nine modules arranged as a three by three matrix and the length of this matrix is 154 mm. The robot propagates a traveling wave inspired by caterpillar locomotion, and it has all three degrees of freedom on a plane (X, Y, and rotation). The speed of the robot is about 18.5 m/h (two body lengths per minute) and it can rotate at a speed of 1.63°/s. The modules have neodymium-iron-boron (NdFeB) magnets embedded and can be easily replaced or combined into other configurations. Two different configurations are presented to demonstrate the possibilities of the modular structure: (1) by removing some modules, the omnidirectional robot can be reassembled into a form that can crawl in a pipe and (2) two omnidirectional robots can crawl close to each other and be assembled automatically into a bigger omnidirectional robot. Omnidirectional motion is important for soft robots to explore unstructured environments. The modular structure gives the soft robot the ability to cope with the challenges of different environments and tasks.

  14. Jumping robots: a biomimetic solution to locomotion across rough terrain.

    Science.gov (United States)

    Armour, Rhodri; Paskins, Keith; Bowyer, Adrian; Vincent, Julian; Megill, William; Bomphrey, Richard

    2007-09-01

    This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection.

  15. Effects of wearing lower leg compression sleeves on locomotion economy.

    Science.gov (United States)

    Kurz, Eduard; Anders, Christoph

    2018-09-01

    The purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p  0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

  16. Reciprocal locomotion of dense swimmers in Stokes flow

    International Nuclear Information System (INIS)

    Gonzalez-Rodriguez, David; Lauga, Eric

    2009-01-01

    Due to the kinematic reversibility of Stokes flow, a body executing a reciprocal motion (a motion in which the sequence of body configurations remains identical under time reversal) cannot propel itself in a viscous fluid in the limit of negligible inertia; this result is known as Purcell's scallop theorem. In this limit, the Reynolds numbers based on the fluid inertia and on the body inertia are all zero. Previous studies characterized the breakdown of the scallop theorem with fluid inertia. In this paper we show that, even in the absence of fluid inertia, certain dense bodies undergoing reciprocal motion are able to swim. Using Lorentz's reciprocal theorem, we first derive the general differential equations that govern the locomotion kinematics of a dense swimmer. We demonstrate that no reciprocal swimming is possible if the body motion consists only of tangential surface deformation (squirming). We then apply our general formulation to compute the locomotion of four simple swimmers, each with a different spatial asymmetry, that perform normal surface deformations. We show that the resulting swimming speeds (or rotation rates) scale as the first power of a properly defined 'swimmer Reynolds number', demonstrating thereby a continuous breakdown of the scallop theorem with body inertia.

  17. Paper-based Pneumatic Locomotive Robot with Sticky Actuator

    Directory of Open Access Journals (Sweden)

    Du Xiaohan

    2016-01-01

    Full Text Available Demands for small-scale and low-cost robots have witnessed a great increase in recent years [1–5]. This paper introduces the design and fabrication of a novel, simple, low-cost and designer-friendly locomotive robot. The materials and tools to build the robot originate from everyday life. The robot is pneumatically powered and manually controlled by simply pumping and vacuuming the syringe repeatedly, which realizes reliable locomotion by folding and opening of the planes. In order to realize this complicated motion, a “3D Sticky Actuator” is developed. The motion and force analysis of actuator are then modelled by the numerical method to develop the relations between design parameters. This suggests a systematic and user interactive way of manufacturing various shapes of the actuator, depending on user-defined road condition (e.g. obstacles and slopes and other constraints. One key advantage of the paper-based robot is suggested by its high feasibility.

  18. Fluid Flow Simulation and Energetic Analysis of Anomalocarididae Locomotion

    Science.gov (United States)

    Mikel-Stites, Maxwell; Staples, Anne

    2014-11-01

    While an abundance of animal locomotion simulations have been performed modeling the motions of living arthropods and aquatic animals, little quantitative simulation and reconstruction of gait parameters has been done to model the locomotion of extinct animals, many of which bear little physical resemblance to their modern descendants. To that end, this project seeks to analyze potential swimming patterns used by the anomalocaridid family, (specifically Anomalocaris canadensis, a Cambrian Era aquatic predator), and determine the most probable modes of movement. This will serve to either verify or cast into question the current assumed movement patterns and properties of these animals and create a bridge between similar flexible-bodied swimmers and their robotic counterparts. This will be accomplished by particle-based fluid flow simulations of the flow around the fins of the animal, as well as an energy analysis of a variety of sample gaits. The energy analysis will then be compared to the extant information regarding speed/energy use curves in an attempt to determine which modes of swimming were most energy efficient for a given range of speeds. These results will provide a better understanding of how these long-extinct animals moved, possibly allowing an improved understanding of their behavioral patterns, and may also lead to a novel potential platform for bio-inspired underwater autonomous vehicles (UAVs).

  19. A novel controller for bipedal locomotion integrating feed-forward and feedback mechanisms

    NARCIS (Netherlands)

    Xiong, Xiaofeng; Sartori, Massimo; Dosen, Strahinja; González-Vargas, José; Wörgötter, Florentin; Farina, Dario; Ibanez, J.; González-Vargas, J.; Azorin, J.M.; Akay, M.; Pons, J.L.

    2017-01-01

    It has been recognized that bipedal locomotion is controlled using feed-forward (e.g., patterned) and feedback (e.g., reflex) control schemes. However, most current controllers fail to integrate the two schemes to simplify speed control of bipedal locomotion. To solve this problem, we here propose a

  20. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Science.gov (United States)

    2010-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs to...

  1. 49 CFR 231.15 - Steam locomotives used in road service.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotives used in road service. 231.15 Section 231.15 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.15 Steam locomotives used...

  2. 49 CFR 229.9 - Movement of non-complying locomotives.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of non-complying locomotives. 229.9... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.9 Movement of non... restrictions necessary for safely conducting the movement; (2)(i) The engineer in charge of the movement of the...

  3. The G6. A heavy-duty, six-wheeled shunting locomotive

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Tim [Vossloh Locomotives GmbH, Kiel (Germany). Development and Standardisation Group

    2010-05-15

    Nowadays, railway operating companies need robust, reliable and versatile locomotives. Vossloh has shown one way that future developments are likely to go with its 'G6' six-wheeled shunting locomotive, which features a central driver's cab. (orig.)

  4. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Shop buildings-locomotives (account XX-19-24... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair and...

  5. Design and analysis of an optimal hopper for use in resonance-based locomotion

    NARCIS (Netherlands)

    Wanders, Ivor; Folkertsma, Gerrit Adriaan; Stramigioli, Stefano

    Quadrupedal running is an efficient form of locomotion found in nature, which serves as an inspiration for robotics. We believe that a resonance-based approach is the path towards energy-efficient legged locomotion and running robots. The first step in working towards this goal is creating an

  6. Investigations into dynamics of a draft of mine cars with two locomotives during electric braking

    Energy Technology Data Exchange (ETDEWEB)

    Sikora-Iliew, R; Szklarski, L; Thuc, Thai Duy

    1983-03-01

    The computerized simulation of electric braking of a draft of GRANBY-5 mine cars and two locomotives (Ld2 locomotives with LDO30 electric series motors) is discussed. The following stages of simulation are analyzed: constructing a mathematical model of the draft of mine cars during electric (dynamic) braking, equations which describe dynamic states of locomotives, mine cars and electric motors during dynamic braking, equations for stability assessment of the draft during dynamic braking. The analog model for simulation of dynamic braking of the draft is given. Simulation results are shown in 10 diagrams. The WAT-1000 hybrid computer is used. Simulation shows that dynamic braking causes occurrence of maximum forces in the couplers between a locomotive and a mine car. When two locomotives are used the maximum force in couplers is lower than in a draft with one locomotive. Braking distance does not depend on position of locomotives in a draft of mine cars. Doubling draft speed causes braking distance to increase by 4 times. Optimum stability conditions of a draft of mine cars are guaranteed when one locomotive is placed at the draft head and a second is separated from the first one by one third of the draft length. 6 references

  7. 49 CFR Appendix D to Part 238 - Requirements for External Fuel Tanks on Tier I Locomotives

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Requirements for External Fuel Tanks on Tier I..., App. D Appendix D to Part 238—Requirements for External Fuel Tanks on Tier I Locomotives The... properties of the locomotive fuel tank to reduce the risk of fuel spillage to acceptable levels under...

  8. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Science.gov (United States)

    2010-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists of...

  9. Synchronization Between Two Different Switched Chaotic Systems By Switching Control

    Directory of Open Access Journals (Sweden)

    Du Li Ming

    2016-01-01

    Full Text Available This paper is concerned with the synchronization problem of two different switched chaotic systems, considering the general case that the master-slave switched chaotic systems have uncertainties. Two basic problems are considered: one is projective synchronization of switched chaotic systems under arbitrary switching; the other is projective synchronization of switched chaotic systems by design of switching when synchronization cannot achieved by using any subsystems alone. For the two problems, common Lyapunov function method and multiple Lyapunov function method are used respectively, an adaptive control scheme has been presented, some sufficient synchronization conditions are attainted, and the switching signal is designed. Finally, the numerical simulation is provide to show the effectiveness of our method.

  10. [The concept and definition of locomotive syndrome in a super-aged society].

    Science.gov (United States)

    Nakamura, Kozo; Yoshimura, Noriko; Akune, Toru; Ogata, Toru; Tanaka, Sakae

    2014-10-01

    The population of elderly individuals who need nursing care is rapidly increasing in Japan. Locomotive syndrome involves a decrease in mobility due to locomotive organ dysfunction, and increases risk for dependency on nursing care service. Because gait speed and chair stand time are correlated with such risks, patients with locomotive syndrome are assessed using brief methods such as the two-step test, which involves dividing the maximum stride length by the height of the patient, and the stand-up test, which involves standing on one or both legs at different heights. One leg standing and squatting are recommended as beneficial locomotive home exercises. Locomotive syndrome has been recognized widely in Japan, and included in the National Health Promotion Movement (2013-2022).

  11. A Specific Population of Reticulospinal Neurons Controls the Termination of Locomotion.

    Science.gov (United States)

    Juvin, Laurent; Grätsch, Swantje; Trillaud-Doppia, Emilie; Gariépy, Jean-François; Büschges, Ansgar; Dubuc, Réjean

    2016-06-14

    Locomotion requires the proper sequencing of neural activity to start, maintain, and stop it. Recently, brainstem neurons were shown to specifically stop locomotion in mammals. However, the cellular properties of these neurons and their activity during locomotion are still unknown. Here, we took advantage of the lamprey model to characterize the activity of a cell population that we now show to be involved in stopping locomotion. We find that these neurons display a burst of spikes that coincides with the end of swimming activity. Their pharmacological activation ends ongoing swimming, whereas the inactivation of these neurons dramatically impairs the rapid termination of swimming. These neurons are henceforth referred to as stop cells, because they play a crucial role in the termination of locomotion. Our findings contribute to the fundamental understanding of motor control and provide important details about the cellular mechanisms involved in locomotor termination. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  12. Identification of a brainstem circuit regulating visual cortical state in parallel with locomotion.

    Science.gov (United States)

    Lee, A Moses; Hoy, Jennifer L; Bonci, Antonello; Wilbrecht, Linda; Stryker, Michael P; Niell, Cristopher M

    2014-07-16

    Sensory processing is dependent upon behavioral state. In mice, locomotion is accompanied by changes in cortical state and enhanced visual responses. Although recent studies have begun to elucidate intrinsic cortical mechanisms underlying this effect, the neural circuits that initially couple locomotion to cortical processing are unknown. The mesencephalic locomotor region (MLR) has been shown to be capable of initiating running and is associated with the ascending reticular activating system. Here, we find that optogenetic stimulation of the MLR in awake, head-fixed mice can induce both locomotion and increases in the gain of cortical responses. MLR stimulation below the threshold for overt movement similarly changed cortical processing, revealing that MLR's effects on cortex are dissociable from locomotion. Likewise, stimulation of MLR projections to the basal forebrain also enhanced cortical responses, suggesting a pathway linking the MLR to cortex. These studies demonstrate that the MLR regulates cortical state in parallel with locomotion. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  14. Optical fiber switch

    Science.gov (United States)

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  15. Coulomb Blockade Plasmonic Switch.

    Science.gov (United States)

    Xiang, Dao; Wu, Jian; Gordon, Reuven

    2017-04-12

    Tunnel resistance can be modulated with bias via the Coulomb blockade effect, which gives a highly nonlinear response current. Here we investigate the optical response of a metal-insulator-nanoparticle-insulator-metal structure and show switching of a plasmonic gap from insulator to conductor via Coulomb blockade. By introducing a sufficiently large charging energy in the tunnelling gap, the Coulomb blockade allows for a conductor (tunneling) to insulator (capacitor) transition. The tunnelling electrons can be delocalized over the nanocapacitor again when a high energy penalty is added with bias. We demonstrate that this has a huge impact on the plasmonic resonance of a 0.51 nm tunneling gap with ∼70% change in normalized optical loss. Because this structure has a tiny capacitance, there is potential to harness the effect for high-speed switching.

  16. Cryogenic switched MOSFET characterization

    Science.gov (United States)

    1981-01-01

    Both p channel and n channel enhancement mode MOSFETs can be readily switched on and off at temperatures as low as 2.8 K so that switch sampled readout of a VLWIR Ge:Ga focal plane is electronically possible. Noise levels as low as 100 rms electrons per sample (independent of sample rate) can be achieved using existing p channel MOSFETs, at overall rates up to 30,000 samples/second per multiplexed channel (e.g., 32 detectors at a rate of almost 1,000 frames/second). Run of the mill devices, including very low power dissipation n channel FETs would still permit noise levels of the order of 500 electrons/sample.

  17. Practical switching power supply design

    CERN Document Server

    Brown, Martin C

    1990-01-01

    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  18. Descending brain neurons in larval lamprey: Spinal projection patterns and initiation of locomotion

    Science.gov (United States)

    Shaw, Albert C.; Jackson, Adam W.; Holmes, Tamra; Thurman, Suzie; Davis, G.R.; McClellan, Andrew D.

    2010-01-01

    In larval lamprey, partial lesions were made in the rostral spinal cord to determine which spinal tracts are important for descending activation of locomotion and to identify descending brain neurons that project in these tracts. In whole animals and in vitro brain/spinal cord preparations, brain-initiated spinal locomotor activity was present when the lateral or intermediate spinal tracts were spared but usually was abolished when the medial tracts were spared. We previously showed that descending brain neurons are located in eleven cell groups, including reticulospinal (RS) neurons in the mesenecephalic reticular nucleus (MRN) as well as the anterior (ARRN), middle (MRRN), and posterior (PRRN) rhombencephalic reticular nuclei. Other descending brain neurons are located in the diencephalic (Di) as well as the anterolateral (ALV), dorsolateral (DLV), and posterolateral (PLV) vagal groups. In the present study, the Mauthner and auxillary Mauthner cells, most neurons in the Di, ALV, DLV, and PLV cell groups, and some neurons in the ARRN and PRRN had crossed descending axons. The majority of neurons projecting in medial spinal tracts included large identified Müller cells and neurons in the Di, MRN, ALV, and DLV. Axons of individual descending brain neurons usually did not switch spinal tracts, have branches in multiple tracts, or cross the midline within the rostral cord. Most neurons that projected in the lateral/intermediate spinal tracts were in the ARRN, MRRN, and PRRN. Thus, output neurons of the locomotor command system are distributed in several reticular nuclei, whose neurons project in relatively wide areas of the cord. PMID:20510243

  19. Composite Material Switches

    Science.gov (United States)

    Javadi, Hamid (Inventor)

    2002-01-01

    A device to protect electronic circuitry from high voltage transients is constructed from a relatively thin piece of conductive composite sandwiched between two conductors so that conduction is through the thickness of the composite piece. The device is based on the discovery that conduction through conductive composite materials in this configuration switches to a high resistance mode when exposed to voltages above a threshold voltage.

  20. MCT/MOSFET Switch

    Science.gov (United States)

    Rippel, Wally E.

    1990-01-01

    Metal-oxide/semiconductor-controlled thyristor (MCT) and metal-oxide/semiconductor field-effect transistor (MOSFET) connected in switching circuit to obtain better performance. Offers high utilization of silicon, low forward voltage drop during "on" period of operating cycle, fast turnon and turnoff, and large turnoff safe operating area. Includes ability to operate at high temperatures, high static blocking voltage, and ease of drive.

  1. Python Switch Statement

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The Python programming language does not have a built in switch/case control structure as found in many other high level programming languages. It is thought by some that this is a deficiency in the language, and the control structure should be added. This paper demonstrates that not only is the control structure not needed, but that the methods available in Python are more expressive than built in case statements in other high level languages.

  2. 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.

  3. Lifestyle factors are significantly associated with the locomotive syndrome: a cross-sectional study.

    Science.gov (United States)

    Akahane, Manabu; Yoshihara, Shingo; Maeyashiki, Akie; Tanaka, Yasuhito; Imamura, Tomoaki

    2017-10-18

    The Japanese Orthopedic Association first proposed the concept of "locomotive syndrome" in 2007. It refers to circumstances in which elderly people need nursing care services or are at high risk of requiring such services within a short time. Recently, the public health burden of providing nursing care for elderly individuals has increased. Therefore, locomotive syndrome, and the means of preventing it, are a major public health focus in Japan. The purpose of this study was to investigate the relationships of lifestyle factors, such as smoking, alcohol consumption, sleep duration, and dental health, with locomotive syndrome. We conducted a cross-sectional study using an internet panel survey. The participants comprised 747 individuals aged 30-90 years. Factors related to demographics (age, sex), general health (number of teeth, presence of periodontal disease), and lifestyle (smoking, alcohol consumption, sleep duration) were assessed. We also used the 25-question Geriatric Locomotive Function Scale to determine whether each participant had locomotive syndrome. Multivariate analysis was conducted using logistic regression to investigate the independent relationships between locomotive syndrome and lifestyle factors after adjusting for sex and age. A greater proportion of women (17.7%) than men (11.2%) had locomotive syndrome (p syndrome compared with those aged syndrome, whereas sleep duration was not. The frequency of alcohol consumption, except for daily drinking, was also associated with locomotive syndrome. Our study indicates that lifestyle factors, such as smoking and number of existing teeth, may partly affect the prevalence of locomotive syndrome. Hence, lifestyle modifications, such as improving oral hygiene and promoting cessation of smoking, are important means to reduce the risk of locomotive syndrome and should be promoted by public health staff.

  4. Ferroelectric switching of elastin

    Science.gov (United States)

    Liu, Yuanming; Cai, Hong-Ling; Zelisko, Matthew; Wang, Yunjie; Sun, Jinglan; Yan, Fei; Ma, Feiyue; Wang, Peiqi; Chen, Qian Nataly; Zheng, Hairong; Meng, Xiangjian; Sharma, Pradeep; Zhang, Yanhang; Li, Jiangyu

    2014-01-01

    Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm2, whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications. PMID:24958890

  5. PROSPECTS OF THE PRIVATE LOCOMOTIVES USAGE FOR GOODS TRAFFIC IN THE DIRECTION OF SEA PORTS

    Directory of Open Access Journals (Sweden)

    D. M. Kozachenko

    2017-12-01

    Full Text Available Purpose. At the present time, Ukraine's mainline railway transport is entirely in state ownership. Ukraine has undertaken to implement the European Union Directives providing of non-discriminatory access to the railway infrastructure of independent carriers. A considerable quantity of options significantly affects the working conditions of carriers that do not depend on Ukrzaliznytsia. One of the tasks that arises when performing transportation by independent carriers is the organization of private locomotives operation and their servicing by engine crews. The purpose of the article is to evaluate the technical characteristic of the private locomotives usage in order to perform goods traffic in the direction of sea ports. Methodology. The researches were carried out on the basis of methods for organizing the operational work of railways and methods of traction calculations. Findings. The paper highlights the problem of goods traffic organization to seaports by independent carriers. It determines the requirements for equipment for diesel locomotives and electric locomotives depending on the distance of transportation. Permissible distances that can be served by engine crews in performing the requirements for the duration of their continuous operation were also determined. Schemes of infrastructure objects location for the locomotives and engine crews operation have been developed. It was established that diesel locomotives of independent carriers will be able to serve transportation between loading and unloading stations up to 822 km, and electric locomotives up to 1000 km with the construction of the main part of the locomotive infrastructure at the port station. The performed calculations show the potential coverage of rail transportation to sea ports by independent carriers with the use of its own locomotive infrastructure. To define more exactly the haul length of train servicing by locomotives and locomotives by engine crews, it is necessary

  6. System Design and Locomotion of Superball, an Untethered Tensegrity Robot

    Science.gov (United States)

    Sabelhaus, Andrew P.; Bruce, Jonathan; Caluwaerts, Ken; Manovi, Pavlo; Firoozi, Roya Fallah; Dobi, Sarah; Agogino, Alice M.; Sunspiral, Vytas

    2015-01-01

    The Spherical Underactuated Planetary Exploration Robot ball (SUPERball) is an ongoing project within NASA Ames Research Center's Intelligent Robotics Group and the Dynamic Tensegrity Robotics Lab (DTRL). The current SUPERball is the first full prototype of this tensegrity robot platform, eventually destined for space exploration missions. This work, building on prior published discussions of individual components, presents the fully-constructed robot. Various design improvements are discussed, as well as testing results of the sensors and actuators that illustrate system performance. Basic low-level motor position controls are implemented and validated against sensor data, which show SUPERball to be uniquely suited for highly dynamic state trajectory tracking. Finally, SUPERball is shown in a simple example of locomotion. This implementation of a basic motion primitive shows SUPERball in untethered control.

  7. Dynamic control of biped locomotion robot using optimal regulator

    International Nuclear Information System (INIS)

    Sano, Akihito; Furusho, Junji

    1988-01-01

    For moving in indoor space, it is generally recognized that biped locomotion is suitable. This paper proposes a hierarchical control strategy for the lower level where the position control or the force control at each joint is implemented. In the upper level control, the robot motion is divided into a sagittal plane and a lateral plane. We applied the optimal control algorithm to the motion control in the lateral plane in order to improve the robustness of the control system. The effects of these control schemes are shown by the experiments using the new walking robot BLR-G 1 and the parallel calculation system. BLR-G 1 has 9 degrees of freedom and equips the foot-pressure-sensors and a rate gyroscope. Complete dynamic walking is realized, in which the cycle for each step is about 1.0 second. (author)

  8. Adaptive Gaze Strategies for Locomotion with Constricted Visual Field

    Directory of Open Access Journals (Sweden)

    Colas N. Authié

    2017-07-01

    Full Text Available In retinitis pigmentosa (RP, loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10–25° in diameter, and nine healthy subjects were asked to walk in one of three directions—straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present, of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures.

  9. Fossils, feet and the evolution of human bipedal locomotion.

    Science.gov (United States)

    Harcourt-Smith, W E H; Aiello, L C

    2004-05-01

    We review the evolution of human bipedal locomotion with a particular emphasis on the evolution of the foot. We begin in the early twentieth century and focus particularly on hypotheses of an ape-like ancestor for humans and human bipedal locomotion put forward by a succession of Gregory, Keith, Morton and Schultz. We give consideration to Morton's (1935) synthesis of foot evolution, in which he argues that the foot of the common ancestor of modern humans and the African apes would be intermediate between the foot of Pan and Hylobates whereas the foot of a hypothetical early hominin would be intermediate between that of a gorilla and a modern human. From this base rooted in comparative anatomy of living primates we trace changing ideas about the evolution of human bipedalism as increasing amounts of postcranial fossil material were discovered. Attention is given to the work of John Napier and John Robinson who were pioneers in the interpretation of Plio-Pleistocene hominin skeletons in the 1960s. This is the period when the wealth of evidence from the southern African australopithecine sites was beginning to be appreciated and Olduvai Gorge was revealing its first evidence for Homo habilis. In more recent years, the discovery of the Laetoli footprint trail, the AL 288-1 (A. afarensis) skeleton, the wealth of postcranial material from Koobi Fora, the Nariokotome Homo ergaster skeleton, Little Foot (Stw 573) from Sterkfontein in South Africa, and more recently tantalizing material assigned to the new and very early taxa Orrorin tugenensis, Ardipithecus ramidus and Sahelanthropus tchadensis has fuelled debate and speculation. The varying interpretations based on this material, together with changing theoretical insights and analytical approaches, is discussed and assessed in the context of new three-dimensional morphometric analyses of australopithecine and Homo foot bones, suggesting that there may have been greater diversity in human bipedalism in the earlier phases

  10. Adaptive Gaze Strategies for Locomotion with Constricted Visual Field

    Science.gov (United States)

    Authié, Colas N.; Berthoz, Alain; Sahel, José-Alain; Safran, Avinoam B.

    2017-01-01

    In retinitis pigmentosa (RP), loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10–25° in diameter, and nine healthy subjects were asked to walk in one of three directions—straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present), of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures. PMID:28798674

  11. Undulatory locomotion of finite filaments: lessons from Caenorhabditis elegans

    International Nuclear Information System (INIS)

    Berman, R S; Kenneth, O; Sznitman, J; Leshansky, A M

    2013-01-01

    Undulatory swimming is a widespread propulsion strategy adopted by many small-scale organisms including various single-cell eukaryotes and nematodes. In this work, we report a comprehensive study of undulatory locomotion of a finite filament using (i) approximate resistive force theory (RFT) assuming a local nature of hydrodynamic interaction between the filament and the surrounding viscous liquid and (ii) particle-based numerical computations taking into account the intra-filament hydrodynamic interaction. Using the ubiquitous model of a propagating sinusoidal waveform, we identify the limit of applicability of the RFT and determine the optimal propulsion gait in terms of (i) swimming distance per period of undulation and (ii) hydrodynamic propulsion efficiency. The occurrence of the optimal swimming gait maximizing hydrodynamic efficiency at finite wavelength in particle-based computations diverges from the prediction of the RFT. To compare the model swimmer powered by sine wave undulations to biological undulatory swimmers, we apply the particle-based approach to study locomotion of the model organism nematode Caenorhabditis elegans using the swimming gait extracted from experiments. The analysis reveals that even though the amplitude and the wavenumber of undulations are similar to those determined for the best performing sinusoidal swimmer, C. elegans overperforms the latter in terms of both displacement and hydrodynamic efficiency. Further comparison with other undulatory microorganisms reveals that many adopt waveforms with characteristics similar to the optimal model swimmer, yet real swimmers still manage to beat the best performing sine-wave swimmer in terms of distance covered per period. Overall our results underline the importance of further waveform optimization, as periodic undulations adopted by C. elegans and other organisms deviate considerably from a simple sine wave. (paper)

  12. Kinematics and ontogeny of locomotion in monkeys and human babies.

    Science.gov (United States)

    Niemitz, Carsten

    2002-03-01

    Early ontogenetic stages are often assumed to reflect or to be similar to past phylogenetic stages within the evolution of man. Therefore, as a first step, the quadrupedal crawling locomotion of human children was analysed and compared to the quadrupedal walk of Macaca fascicularis. The movements of the human child were not only more irregular, they differed from the walk of the monkey mainly through extraordinarily short swing phases, and also through strong scoliotic movements of the spine. There is a compulsory synchronisation in the hip and knee joint movements of the human crawling baby. We conclude that human crawling may be a behavioural recapitulation of a quadrupedal evolutionary stage. However, with reference to kinematics, man is not only characterised by his unique, habitually bipedal, upright gait but also by a second, equally unique locomotion, namely crawling, which he assumes for a short phase during his first year of life.--The walking movements of the limbs in toddling infants were mainly characterised by i) rather stiff, abducted arms, which were moved mostly by spine torsions (similar to those of bipedally walking Gorilla) and not as a suspensory pendulum. However, they rather work as levers for the elastic torsion pendulum of the spine. ii) They are also characterised by frequently lacking the minor knee flexion, which occurs at about the heel strike within each stride of the adult human. Besides many other details of the results, foot movements differed from adult ones mainly in that the whole plantar surface was placed flat on the ground within a few milliseconds.

  13. Natural Translating Locomotion Modulates Cortical Activity at Action Observation

    Directory of Open Access Journals (Sweden)

    Thierry Pozzo

    2017-11-01

    Full Text Available The present study verified if the translational component of locomotion modulated cortical activity recorded at action observation. Previous studies focusing on visual processing of biological motion mainly presented point light walker that were fixed on a spot, thus removing the net translation toward a goal that yet remains a critical feature of locomotor behavior. We hypothesized that if biological motion recognition relies on the transformation of seeing in doing and its expected sensory consequences, a significant effect of translation compared to centered displays on sensorimotor cortical activity is expected. To this aim, we explored whether EEG activity in the theta (4–8 Hz, alpha (8–12 Hz, beta 1 (14–20 Hz and beta 2 (20–32 Hz frequency bands exhibited selectivity as participants viewed four types of stimuli: a centered walker, a centered scrambled, a translating walker and a translating scrambled. We found higher theta synchronizations for observed stimulus with familiar shape. Higher power decreases in the beta 1 and beta 2 bands, indicating a stronger motor resonance was elicited by translating compared to centered stimuli. Finally, beta bands modulation in Superior Parietal areas showed that the translational component of locomotion induced greater motor resonance than human shape. Using a Multinomial Logistic Regression classifier we found that Dorsal-Parietal and Inferior-Frontal regions of interest (ROIs, constituting the core of action-observation system, were the only areas capable to discriminate all the four conditions, as reflected by beta activities. Our findings suggest that the embodiment elicited by an observed scenario is strongly mediated by horizontal body displacement.

  14. Relating appendicular skeletal variation of sigmodontine rodents to locomotion modes in a phylogenetic context.

    Science.gov (United States)

    Carvalho Coutinho, Ludmilla; Alves de Oliveira, João

    2017-10-01

    Sigmodontinae rodents constitute the second-largest subfamily among mammals. Alongside the taxonomic diversity, they are also ecologically diverse, exhibiting a wide array of locomotion modes, with semifossorial, terrestrial, semiaquatic, scansorial, arboreal, and saltatorial forms. To understand the ecomorphologic aspects that allow these rodents to display such locomotion diversity, we analyzed 35 qualitative characters of the appendicular skeleton (humerus, ulna, radius, scapula, femur, tibia, ilium, ischium and pubis) in 795 specimens belonging to 64 species, 34 genera and 10 tribes, representing all locomotion modes assigned to this subfamily. We performed a statistical analysis based upon the coefficient of trait differentiation to test the congruence of character states and the different locomotion modes. We also mapped characters states in a molecular phylogeny in order to reconstruct ancestral states and to evaluate how appendicular characters evolved within main lineages of Sigmodontinae radiation under a phylogenetic framework. The statistical analyses revealed six characters related to specific locomotion modes, except terrestrial. The mapping and parsimony ancestral states reconstruction identified two characters with phylogenetical signal and eight characters that are exclusively or more frequently recorded in certain modes of locomotion, four of them also detected by the statistical analysis. Notwithstanding the documented morphological variation, few changes characterize the transition to each of the locomotion modes, at least regarding the appendicular skeleton. This finding corroborates previous results that showed that sigmodontines exhibit an all-purpose appendicular morphology that allows them to use and explore a great variety of habitats. © 2017 Anatomical Society.

  15. Acute food deprivation reverses morphine-induced locomotion deficits in M5 muscarinic receptor knockout mice.

    Science.gov (United States)

    Steidl, Stephan; Lee, Esther; Wasserman, David; Yeomans, John S

    2013-09-01

    Lesions of the pedunculopontine tegmental nucleus (PPT), one of two sources of cholinergic input to the ventral tegmental area (VTA), block conditioned place preference (CPP) for morphine in drug-naïve rats. M5 muscarinic cholinergic receptors, expressed by midbrain dopamine neurons, are critical for the ability of morphine to increase nucleus accumbens dopamine levels and locomotion, and for morphine CPP. This suggests that M5-mediated PPT cholinergic inputs to VTA dopamine neurons critically contribute to morphine-induced dopamine activation, reward and locomotion. In the current study we tested whether food deprivation, which reduces PPT contribution to morphine CPP in rats, could also reduce M5 contributions to morphine-induced locomotion in mice. Acute 18-h food deprivation reversed the phenotypic differences usually seen between non-deprived wild-type and M5 knockout mice. That is, food deprivation increased morphine-induced locomotion in M5 knockout mice but reduced morphine-induced locomotion in wild-type mice. Food deprivation increased saline-induced locomotion equally in wild-type and M5 knockout mice. Based on these findings, we suggest that food deprivation reduces the contribution of M5-mediated PPT cholinergic inputs to the VTA in morphine-induced locomotion and increases the contribution of a PPT-independent pathway. The contributions of cholinergic, dopaminergic and GABAergic neurons to the effects of acute food deprivation are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Experimental investigation into the mechanism of the polygonal wear of electric locomotive wheels

    Science.gov (United States)

    Tao, Gongquan; Wang, Linfeng; Wen, Zefeng; Guan, Qinghua; Jin, Xuesong

    2018-06-01

    Experiments were conducted at field sites to investigate the mechanism of the polygonal wear of electric locomotive wheels. The polygonal wear rule of electric locomotive wheels was obtained. Moreover, two on-track tests have been carried out to investigate the vibration characteristics of the electric locomotive's key components. The measurement results of wheels out-of-round show that most electric locomotive wheels exhibit polygonal wear. The main centre wavelength in the 1/3 octave bands is 200 mm and/or 160 mm. The test results of vibration characteristics indicate that the dominating frequency of the vertical acceleration measured on the axle box is approximately equal to the passing frequency of a polygonal wheel, and does not vary with the locomotive speed during the acceleration course. The wheelset modal analysis using the finite element method (FEM) indicates that the first bending resonant frequency of the wheelset is quite close to the main vibration frequency of the axle box. The FEM results are verified by the experimental modal analysis of the wheelset. Moreover, different plans were designed to verify whether the braking system and the locomotive's adhesion control have significant influence on the wheel polygon or not. The test results indicate that they are not responsible for the initiation of the wheel polygon. The first bending resonance of the wheelset is easy to be excited in the locomotive operation and it is the root cause of wheel polygon with centre wavelength of 200 mm in the 1/3 octave bands.

  17. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    Science.gov (United States)

    Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

    2015-12-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  18. MENGAPA PERUSAHAAN MELAKUKAN AUDITOR SWITCH?

    Directory of Open Access Journals (Sweden)

    Kadek Sumadi

    2011-01-01

    Full Text Available The existence of a large number of accounting firms allowsprovides companies choices whether to stay with current firm or switchto another accounting firm. Decision of Minister of FinanceNo.423/KMK.06/2002 states that a company must switch auditor afterfive years of consecutive assignment. This is mandatory. The questionrises when a company voluntarily switches its auditor. Why does thishappen?One of the reasons is that management does not satisfy withauditor opinion, except for unqualified opinion. New management teamwould directly or indirectly encourage auditor switch to align accountingand reporting policies. Moreover an expanding company expects positivereaction when it does auditor switch. Profitability is also one reason fora company to switch auditor, for example, when a company earns moreprofit it tends to hire more credible auditor. On the other hand, when thecompany faces a financial distress, it probably would switch auditor aswell.

  19. Low-Crosstalk Composite Optical Crosspoint Switches

    Science.gov (United States)

    Pan, Jing-Jong; Liang, Frank

    1993-01-01

    Composite optical switch includes two elementary optical switches in tandem, plus optical absorbers. Like elementary optical switches, composite optical switches assembled into switch matrix. Performance enhanced by increasing number of elementary switches. Advantage of concept: crosstalk reduced to acceptably low level at moderate cost of doubling number of elementary switches rather than at greater cost of tightening manufacturing tolerances and exerting more-precise control over operating conditions.

  20. The G6 - a heavy-duty six-wheeled shunting locomotive; Dreiachsige Hochleistungsrangierlokomotive G6

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Tim [Vossloh Locomotives GmbH, Kiel (Germany). Entwicklung und Standardisierung

    2009-03-15

    With the three-axle shunter G6, exhibited at Innotrans 2008, the renowned producer of rail vehicles Vossloh Locomotives GmbH marks the beginning of a generational change - not only for three-axle but also for four-axle locomotives. In order to replace the type G765C the G6 has been developed in close cooperation with potential customers. Their request concerning robustness and reliability as well as the equipment options set standards for central driver's cab locomotives in general and lead the way for future four-axle replacements within the Vossloh product family. (orig.)

  1. Compound semiconductor optical waveguide switch

    Science.gov (United States)

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  2. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  3. Recent developments in switching theory

    CERN Document Server

    Mukhopadhyay, Amar

    2013-01-01

    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  4. Software Switching for Data Acquisition

    CERN Multimedia

    CERN. Geneva; Malone, David

    2016-01-01

    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  5. The New Era of Virtual Reality Locomotion: A Systematic Literature Review of Techniques and a Proposed Typology

    Directory of Open Access Journals (Sweden)

    Costas Boletsis

    2017-09-01

    Full Text Available The latest technical and interaction advancements that took place in the Virtual Reality (VR field have marked a new era, not only for VR, but also for VR locomotion. Although the latest advancements in VR locomotion have raised the interest of both researchers and users in analyzing and experiencing current VR locomotion techniques, the field of research on VR locomotion, in its new era, is still uncharted. In this work, VR locomotion is explored through a systematic literature review investigating empirical studies of VR locomotion techniques from 2014–2017. The review analyzes the VR locomotion techniques that have been studied, their interaction-related characteristics and the research topics that were addressed in these studies. Thirty-six articles were identified as relevant to the literature review, and the analysis of the articles resulted in 73 instances of 11 VR locomotion techniques, such as real-walking, walking-in-place, point and teleport, joystick-based locomotion, and more. Results showed that since the VR revival, the focus of VR locomotion research has been on VR technology and various technological aspects, overshadowing the investigation of user experience. From an interaction perspective, the majority of the utilized and studied VR locomotion techniques were found to be based on physical interaction, exploiting physical motion cues for navigation in VR environments. A significant contribution of the literature review lies in the proposed typology for VR locomotion, introducing four distinct VR locomotion types: motion-based, room scale-based, controller-based and teleportation-based locomotion.

  6. Modeling and Control of Switching Max-Plus-Linear Systems : Rescheduling of railway traffic and changing gaits in legged locomotion

    NARCIS (Netherlands)

    Kersbergen, B.

    2015-01-01

    The operation of many systems can be described by the timing of events. When the system behavior can be described by equations that are "linear'' in the max-plus algebra, which has maximization and addition as its basic operations, the system is called a max-plus-linear system. In many of these

  7. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  8. LCT protective dump-switch tests

    International Nuclear Information System (INIS)

    Parsons, W.M.

    1981-01-01

    Each of the six coils in the Large Coil Task (LCT) has a separate power supply, dump resistor, and switching circuit. Each switching circuit contains five switches, two of which are redundant. The three remaining switches perform separate duties in an emergency dump situation. These three switches were tested to determine their ability to meet the LCT conditions

  9. Physiological aspects of legged terrestrial locomotion the motor and the machine

    CERN Document Server

    Cavagna, Giovanni

    2017-01-01

    This book offers a succinct but comprehensive description of the mechanics of muscle contraction and legged terrestrial locomotion. It describes on the one hand how the fundamental properties of muscle tissue affect the mechanics of locomotion, and on the other, how the mechanics of locomotion modify the mechanism of muscle operation under different conditions. Further, the book reports on the design and results of experiments conducted with two goals. The first was to describe the physiological function of muscle tissue (which may be considered as the “motor”) contracting at a constant length, during shortening, during lengthening, and under a condition that occurs most frequently in the back-and-forth movement of the limbs during locomotion, namely the stretch-shortening cycle of the active muscle. The second objective was to analyze the interaction between the motor and the “machine” (the skeletal lever system) during walking and running in different scenarios with respect to speed, step frequency,...

  10. LSTM-Based Temperature Prediction for Hot-Axles of Locomotives

    Directory of Open Access Journals (Sweden)

    Luo Can

    2017-01-01

    Full Text Available The reliability of locomotives plays a central role for the smooth operation of railway systems. Hot-axle failures are one of the most commonly found problems leading to locomotive accidents. Since the operating status of the locomotive axle bearings can be distinctly reflected by the axle temperatures, online temperature monitoring has become an essential way to detect hot-axle failures. In this work, we explore the feasibility of predict the hot-axle failures by identifying the temperature from predicted nominal values. We propose a data-driven approach based on the Long Short-Term Memory (LSTM network to predict the sensor temperature for axle bearings. The effectiveness of the prediction model was validated with operation data collected from commercial locomotives. With a prediction accuracy is within a few percent, the proposed techniques can be used as a dynamic reference for hot-axle monitoring.

  11. The Effects of Natural Locomotion on Maneuvering Task Performance in Virtual and Real Environments

    National Research Council Canada - National Science Library

    Unguder, Eray

    2001-01-01

    ... treadmill. The motivation for the development of locomotion devices thus far has been driven by the assumption that a The "perfect" device will result in human performance levels comparable to the real world...

  12. Locomotive emissions test stand with particulate matter measurement integration : final report.

    Science.gov (United States)

    2015-10-01

    This project builds upon previous research efforts, in which a complete instruction manual and bill of materials was developed for : a blueprint that allows any organization in the railroad industry to build their own locomotive emissions measurement...

  13. 49 CFR 222.21 - When must a locomotive horn be used?

    Science.gov (United States)

    2010-10-01

    ... or lead cab car shall be sounded when such locomotive or lead cab car is approaching a public highway... equipped with automatic flashing lights and gates and the gates are fully lowered; or (2) There are no...

  14. EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

    Science.gov (United States)

    Weinelt, Martin; von Oppen, Felix

    2012-10-01

    In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on

  15. DETERMINATION OF FRAME FORCE FOR ELECTRIC LOCOMOTIVE VL80 WHEN MOVING IN THE CURVED TRACK SECTIONS

    Directory of Open Access Journals (Sweden)

    A. Y. Kuzyshyn

    2017-06-01

    Full Text Available Purpose. When locomotives move in curved sections of the railway track, horizontal forces arise, which lead to pressing the ridge of the wheel pair to the railway track. The article is aimed to develop a method for determining the frame force acting on the bogie from the side of body of the locomotive section using the current methodology of calculating the lateral force. It is also aimed to determine the basic parameters that influence the value of the frame force. It is necessary to construct the dependencies of the frame force on the travel time of electric locomotive in the corresponding curve changing these parameters. Methodology. As is known, the electric locomotive is a multimass mechanical system. We will assume that this system consists of seven bodies: a body, two frames of carriages and four wheel sets. To determine the lateral force acting on the rail from the wheelset one need to solve differential equations of motion of locomotive bogie in curves of small radius. Using the equations of kinetostatics for wheelset one should come to determining the frame force acting on the car bogie from the side of body of the locomotive section. The nominal geometric and mass parameters of parts and components of electric locomotive are taken in the calculations. The curve radius, the length of transition curve, the length of circular curve, the longitudinal slope of railway track and other parameters are fixed values. Findings. There were obtained calculated values of the frame force of electric locomotive VL80 acting on the bogie from the side of body of the locomotive section. Based on the obtained results there were built the dependencies of frame force on the travel time of electric locomotive on the corresponding curve when changing the speed and corresponding elevation of the outer rail. Originality. On the basis of the existing methodology for calculating the lateral force it was developed the method for determining the frame force acting

  16. Profile and genetic parameters of dairy cattle locomotion score and lameness across lactation.

    Science.gov (United States)

    Kougioumtzis, A; Valergakis, G E; Oikonomou, G; Arsenos, G; Banos, G

    2014-01-01

    This study investigated the profile of locomotion score and lameness before the first calving and throughout the first (n=237) and second (n=66) lactation of 303 Holstein cows raised on a commercial farm. Weekly heritability estimates of locomotion score and lameness, and their genetic and phenotypic correlations with milk yield, body condition score, BW and reproduction traits were derived. Daughter future locomotion score and lameness predictions from their sires��� breeding values for conformation traits were also calculated. First-lactation cows were monitored weekly from 6 weeks before calving to the end of lactation. Second-lactation cows were monitored weekly throughout lactation. Cows were locomotion scored on a scale from one (sound) to five (severely lame); a score greater than or equal to two defined presence of lameness. Cows��� weekly body condition score and BW was also recorded. These records were matched to corresponding milk yield records, where the latter were 7-day averages on the week of inspection. The total number of repeated records amounted to 12 221. Data were also matched to the farm���s reproduction database, from which five traits were derived. Statistical analyses were based on uni- and bivariate random regression models. The profile analysis showed that locomotion and lameness problems in first lactation were fewer before and immediately after calving, and increased as lactation progressed. The profile of the two traits remained relatively constant across the second lactation. Highest heritability estimates were observed in the weeks before first calving (0.66 for locomotion score and 0.54 for lameness). Statistically significant genetic correlations were found for first lactation weekly locomotion score and lameness with body condition score, ranging from ���0.31 to ���0.65 and from ���0.44 to ���0.76, respectively, suggesting that cows genetically pre-disposed for high body condition score

  17. SELECTION OF RATIONAL PARAMETERS OF THE NOMINAL MODE OF ELECTRIC LOCOMOTIVES

    Directory of Open Access Journals (Sweden)

    H. K. Hetman

    2017-02-01

    Full Text Available Purpose.The railways of Ukraine have been operated the locomotives, which are both morally and physically obsolete. Therefore, to ensure the competitiveness of rail transport it is necessary to update the locomotive fleet, and first of all the fleet of electric locomotives, because electrified railways provide the greater part of passenger and freight traffic. In this connection it is of special importance to determine the optimum parameters of the nominal mode of electric rolling stock. The purpose of the work is to examine the features of solution of these problems with respect to electric locomotives. Methodology. Assuming that the limit values of traction force are determined by the conditions of wheel-rail grip, then the power of the nominal mode can be represented as the product of rated speed, estimated friction coefficient, train weight and the coefficients that represent the ratio of the estimated (starting value of traction force to value of traction force the nominal mode and the ratio of the mass of the locomotive to the train weight. Since the mass of the train is not a constant value, there is always a surplus power of the locomotive fleet required for the mastering of a predetermined volume of transportations. Reduced overcapacity of the locomotive fleet can be achieved by introduction of the locomotives of different power, designed for driving trains of different weight that will result in increased completeness of the power use but also in difficulty in selecting of locomotives for trains in operation. The paper shows the method of calculating the optimum values of power, speed and traction force of the nominal mode. It presents the mathematical model of the relationship of traction rate, excessive capacity and power of the traction unit. Findings.It is proved that the power of the traction unit, the total fleet power requirement and the excess of power in absolute units are proportional to the speed of the nominal mode. To

  18. Circuit switched optical networks

    DEFF Research Database (Denmark)

    Kloch, Allan

    2003-01-01

    Some of the most important components required for enabling optical networking are investigated through both experiments and modelling. These all-optical components are the wavelength converter, the regenerator and the space switch. When these devices become "off-the-shelf" products, optical cross......, it is expected that the optical solution will offer an economical benefit for hight bit rate networks. This thesis begins with a discussion of the expected impact on communications systems from the rapidly growing IP traffic, which is expected to become the dominant source for traffic. IP traffic has some...... characteristics, which are best supported by an optical network. The interest for such an optical network is exemplified by the formation of the ACTS OPEN project which aim was to investigate the feasibility of an optical network covering Europe. Part of the work presented in this thesis is carried out within...

  19. Photo-switching element

    Energy Technology Data Exchange (ETDEWEB)

    Masaki, Yuichi

    1987-10-31

    Photo-input MOS transistor (Photo-switching element) cannot give enough ON/OFF ratio but requires an auxiliary condenser for a certain type of application. In addition, PN junction of amorphous silicon is not practical because it gives high leak current resulting in low electromotive force. In this invention, a solar cell was constructed with a lower electrode consisting of a transparent electro-conducting film, a photosensitive part consisting of an amorphous Si layer of p-i-n layer construction, and an upper metal electrode consisting of Cr or Nichrome, and a thin film transistor was placed on the solar cell, and further the upper metal electrode was co-used as a gate electrode of the thin film transistor; this set-up of this invention enabled to attain an efficient photo-electric conversion of the incident light, high electromotive force of the solar cell, and the transistor with high ON/OFF ratio. (3 figs)

  20. Battery switch for downhole tools

    Science.gov (United States)

    Boling, Brian E.

    2010-02-23

    An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

  1. Improved switch-resistor packaging

    Science.gov (United States)

    Redmerski, R. E.

    1980-01-01

    Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

  2. Activation of groups of excitatory neurons in the mammalian spinal cord or hindbrain evokes locomotion

    DEFF Research Database (Denmark)

    Hägglund, Martin; Borgius, Lotta; Dougherty, Kimberly J.

    2010-01-01

    Central pattern generators (CPGs) are spinal neuronal networks required for locomotion. Glutamatergic neurons have been implicated as being important for intrinsic rhythm generation in the CPG and for the command signal for initiating locomotion, although this has not been demonstrated directly. We...... neurons in the spinal cord are critical for initiating or maintaining the rhythm and that activation of hindbrain areas containing the locomotor command regions is sufficient to directly activate the spinal locomotor network....

  3. Inferring Characteristics of Sensorimotor Behavior by Quantifying Dynamics of Animal Locomotion

    Science.gov (United States)

    Leung, KaWai

    Locomotion is one of the most well-studied topics in animal behavioral studies. Many fundamental and clinical research make use of the locomotion of an animal model to explore various aspects in sensorimotor behavior. In the past, most of these studies focused on population average of a specific trait due to limitation of data collection and processing power. With recent advance in computer vision and statistical modeling techniques, it is now possible to track and analyze large amounts of behavioral data. In this thesis, I present two projects that aim to infer the characteristics of sensorimotor behavior by quantifying the dynamics of locomotion of nematode Caenorhabditis elegans and fruit fly Drosophila melanogaster, shedding light on statistical dependence between sensing and behavior. In the first project, I investigate the possibility of inferring noxious sensory information from the behavior of Caenorhabditis elegans. I develop a statistical model to infer the heat stimulus level perceived by individual animals from their stereotyped escape responses after stimulation by an IR laser. The model allows quantification of analgesic-like effects of chemical agents or genetic mutations in the worm. At the same time, the method is able to differentiate perturbations of locomotion behavior that are beyond affecting the sensory system. With this model I propose experimental designs that allows statistically significant identification of analgesic-like effects. In the second project, I investigate the relationship of energy budget and stability of locomotion in determining the walking speed distribution of Drosophila melanogaster during aging. The locomotion stability at different age groups is estimated from video recordings using Floquet theory. I calculate the power consumption of different locomotion speed using a biomechanics model. In conclusion, the power consumption, not stability, predicts the locomotion speed distribution at different ages.

  4. Development of generalized dynamic model of oscillations of cylinder case of diesel engine of locomotive

    Directory of Open Access Journals (Sweden)

    Irina YUTKINA

    2014-03-01

    Full Text Available An engineering method of design, worked out by the authors, is considered in the paper. It allows to carry out design of amplitude-frequency specter and vibration loading of cylinder cases of the diesel engine of locomotive with account of cavitation-erosion damage. Offered method of design of parameters of cavitation-erosion damage may be used in design of new structures of diesel engines of locomotives and systems of cooling.

  5. Research of the possibility of using neural networks in the tests of locomotive hydraulic transmissions

    OpenAIRE

    КЛЮШНИК, І. А.

    2017-01-01

    The possibility of developing a self-diagnostics system of the diesel locomotives hydraulic transmissions information-measuring test system is researched. The use of neural networks and fuzzy logic for the development of a self-diagnostics system of the diesel locomotives hydraulic transmissions information-measuring tests system is proposed. As the initial stage of developing a diagnostic system using neural networks, a neural network is presented which predicts the rotational speed of the h...

  6. Fictive locomotion in the adult decerebrate and spinal mouse in vivo

    DEFF Research Database (Denmark)

    Meehan, Claire Francesca; Grøndahl, Lillian; Nielsen, Jens Bo

    2012-01-01

    Recently, transgenic mice have been created with mutations affecting the components of the mammalian spinal central pattern generator (CPG) for locomotion, however, it has currently only been possible to evoke fictive locomotion in mice, using neonatal in vitro preparations. Here, we demonstrate...... organisation and allowing for future results in transgenic mice to be extrapolated to existing knowledge of CPG components and circuitry obtained in larger species....

  7. Superconductivity, energy storage and switching

    International Nuclear Information System (INIS)

    Laquer, H.L.

    1974-01-01

    The phenomenon of superconductivity can contribute to the technology of energy storage and switching in two distinct ways. On one hand the zero resistivity of the superconductor can produce essentially infinite time constants so that an inductive storage system can be charged from very low power sources. On the other hand, the recovery of finite resistivity in a normal-going superconducting switch can take place in extremely short times, so that a system can be made to deliver energy at a very high power level. Topics reviewed include: physics of superconductivity, limits to switching speed of superconductors, physical and engineering properties of superconducting materials and assemblies, switching methods, load impedance considerations, refrigeration economics, limitations imposed by present day and near term technology, performance of existing and planned energy storage systems, and a comparison with some alternative methods of storing and switching energy. (U.S.)

  8. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  9. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  10. Locomotion of inchworm-inspired robot made of smart soft composite (SSC)

    International Nuclear Information System (INIS)

    Wang, Wei; Lee, Jang-Yeob; Rodrigue, Hugo; Song, Sung-Hyuk; Ahn, Sung-Hoon; Chu, Won-Shik

    2014-01-01

    A soft-bodied robot made of smart soft composite with inchworm-inspired locomotion capable of both two-way linear and turning movement has been proposed, developed, and tested. The robot was divided into three functional parts based on the different functions of the inchworm: the body, the back foot, and the front foot. Shape memory alloy wires were embedded longitudinally in a soft polymer to imitate the longitudinal muscle fibers that control the abdominal contractions of the inchworm during locomotion. Each foot of the robot has three segments with different friction coefficients to implement the anchor and sliding movement. Then, utilizing actuation patterns between the body and feet based on the looping gait, the robot achieves a biomimetic inchworm gait. Experiments were conducted to evaluate the robot’s locomotive performance for both linear locomotion and turning movement. Results show that the proposed robot’s stride length was nearly one third of its body length, with a maximum linear speed of 3.6 mm s −1 , a linear locomotion efficiency of 96.4%, a maximum turning capability of 4.3 degrees per stride, and a turning locomotion efficiency of 39.7%. (paper)

  11. Locomotion-learning behavior relationship in Caenorhabditis elegans following γ-ray irradiation

    International Nuclear Information System (INIS)

    Sakashita, Tetsuya; Hamada, Nobuyuki; Suzuki, Michiyo; Kobayashi, Yasuhiko; Ikeda, Daisuke D.; Yanase, Sumino; Ishii, Naoaki

    2008-01-01

    Learning impairment following ionizing radiation (IR) exposure is an important potential risk in manned space missions. We previously reported the modulatory effects of IR on salt chemotaxis learning in Caenorhabditis elegans. However, little is known about the effects of IR on the functional relationship in the nervous system. In the present study, we investigated the effects of γ-ray exposure on the relationship between locomotion and salt chemotaxis learning behavior. We found that effects of pre-learning irradiation on locomotion were significantly correlated with the salt chemotaxis learning performance, whereas locomotion was not directly related to chemotaxis to NaCl. On the other hand, locomotion was positively correlated with salt chemotaxis of animals which were irradiated during learning, and the correlation disappeared with increasing doses. These results suggest an indirect relationship between locomotion and salt chemotaxis learning in C. elegans, and that IR inhibits the innate relationship between locomotion and chemotaxis, which is related to salt chemotaxis learning conditioning of C. elegans. (author)

  12. Modeling posture-dependent leg actuation in sagittal plane locomotion

    International Nuclear Information System (INIS)

    Schmitt, J; Clark, J

    2009-01-01

    The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

  13. Electric-Pneumatic Actuator: A New Muscle for Locomotion

    Directory of Open Access Journals (Sweden)

    Maziar Ahmad Sharbafi

    2017-10-01

    Full Text Available A better understanding of how actuator design supports locomotor function may help develop novel and more functional powered assistive devices or robotic legged systems. Legged robots comprise passive parts (e.g., segments, joints and connections which are moved in a coordinated manner by actuators. In this study, we propose a novel concept of a hybrid electric-pneumatic actuator (EPA as an enhanced variable impedance actuator (VIA. EPA is consisted of a pneumatic artificial muscle (PAM and an electric motor (EM. In contrast to other VIAs, the pneumatic artificial muscle (PAM within the EPA provides not only adaptable compliance, but also an additional powerful actuator with muscle-like properties, which can be arranged in different combinations (e.g., in series or parallel to the EM. The novel hybrid actuator shares the advantages of both integrated actuator types combining precise control of EM with compliant energy storage of PAM, which are required for efficient and adjustable locomotion. Experimental and simulation results based on the new dynamic model of PAM support the hypothesis that combination of the two actuators can improve efficiency (energy and peak power and performance, while does not increase control complexity and weight, considerably. Finally, the experiments on EPA adapted bipedal robot (knee joint of the BioBiped3 robot show improved efficiency of the actuator at different frequencies.

  14. Energetics and biomechanics of locomotion by red kangaroos (Macropus rufus).

    Science.gov (United States)

    Kram, R; Dawson, T J

    1998-05-01

    As red kangaroos hop faster over level ground, their rate of oxygen consumption (indicating metabolic energy consumption) remains nearly the same. This phenomenon has been attributed to exceptional elastic energy storage and recovery via long compliant tendons in the legs. Alternatively, red kangaroos may have exceptionally efficient muscles. To estimate efficiency, we measured the metabolic cost of uphill hopping, where muscle fibers must perform mechanical work against gravity. We found that uphill hopping was much more expensive than level hopping. The maximal rate of oxygen consumption measured (3 ml O2 kg-1 s-1) exceeds all but a few vertebrate species. However, efficiency values were normal, approximately 30%. At faster level hopping speeds the effective mechanical advantage of the extensor muscles of the ankle joint remained the same. Thus, kangaroos generate the same muscular force at all speeds but do so more rapidly at faster hopping speeds. This contradicts a recent hypothesis for what sets the cost of locomotion. The cost of transport (J kg-1 m-1) decreases at faster hopping speeds, yet red kangaroos prefer to use relatively slow speeds that avoid high levels of tendon stress.

  15. An Adaptive Classification Strategy for Reliable Locomotion Mode Recognition

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2017-09-01

    Full Text Available Algorithms for locomotion mode recognition (LMR based on surface electromyography and mechanical sensors have recently been developed and could be used for the neural control of powered prosthetic legs. However, the variations in input signals, caused by physical changes at the sensor interface and human physiological changes, may threaten the reliability of these algorithms. This study aimed to investigate the effectiveness of applying adaptive pattern classifiers for LMR. Three adaptive classifiers, i.e., entropy-based adaptation (EBA, LearnIng From Testing data (LIFT, and Transductive Support Vector Machine (TSVM, were compared and offline evaluated using data collected from two able-bodied subjects and one transfemoral amputee. The offline analysis indicated that the adaptive classifier could effectively maintain or restore the performance of the LMR algorithm when gradual signal variations occurred. EBA and LIFT were recommended because of their better performance and higher computational efficiency. Finally, the EBA was implemented for real-time human-in-the-loop prosthesis control. The online evaluation showed that the applied EBA effectively adapted to changes in input signals across sessions and yielded more reliable prosthesis control over time, compared with the LMR without adaptation. The developed novel adaptive strategy may further enhance the reliability of neurally-controlled prosthetic legs.

  16. Markerless 3D motion capture for animal locomotion studies

    Directory of Open Access Journals (Sweden)

    William Irvin Sellers

    2014-06-01

    Full Text Available Obtaining quantitative data describing the movements of animals is an essential step in understanding their locomotor biology. Outside the laboratory, measuring animal locomotion often relies on video-based approaches and analysis is hampered because of difficulties in calibration and often the limited availability of possible camera positions. It is also usually restricted to two dimensions, which is often an undesirable over-simplification given the essentially three-dimensional nature of many locomotor performances. In this paper we demonstrate a fully three-dimensional approach based on 3D photogrammetric reconstruction using multiple, synchronised video cameras. This approach allows full calibration based on the separation of the individual cameras and will work fully automatically with completely unmarked and undisturbed animals. As such it has the potential to revolutionise work carried out on free-ranging animals in sanctuaries and zoological gardens where ad hoc approaches are essential and access within enclosures often severely restricted. The paper demonstrates the effectiveness of video-based 3D photogrammetry with examples from primates and birds, as well as discussing the current limitations of this technique and illustrating the accuracies that can be obtained. All the software required is open source so this can be a very cost effective approach and provides a methodology of obtaining data in situations where other approaches would be completely ineffective.

  17. Analyzing locomotion synthesis with feature-based motion graphs.

    Science.gov (United States)

    Mahmudi, Mentar; Kallmann, Marcelo

    2013-05-01

    We propose feature-based motion graphs for realistic locomotion synthesis among obstacles. Among several advantages, feature-based motion graphs achieve improved results in search queries, eliminate the need of postprocessing for foot skating removal, and reduce the computational requirements in comparison to traditional motion graphs. Our contributions are threefold. First, we show that choosing transitions based on relevant features significantly reduces graph construction time and leads to improved search performances. Second, we employ a fast channel search method that confines the motion graph search to a free channel with guaranteed clearance among obstacles, achieving faster and improved results that avoid expensive collision checking. Lastly, we present a motion deformation model based on Inverse Kinematics applied over the transitions of a solution branch. Each transition is assigned a continuous deformation range that does not exceed the original transition cost threshold specified by the user for the graph construction. The obtained deformation improves the reachability of the feature-based motion graph and in turn also reduces the time spent during search. The results obtained by the proposed methods are evaluated and quantified, and they demonstrate significant improvements in comparison to traditional motion graph techniques.

  18. Calculation of locomotive traction force in transient rolling contact

    Directory of Open Access Journals (Sweden)

    Voltr P.

    2017-06-01

    Full Text Available To represent thewheel-rail contact in numerical simulations of rail vehicles, simplified models (Fastsim, Pola´ch etc. are usually employed. These models are designed for steady rolling only, which is perfectly suitable in many cases. However, it is shown to be limiting for simulations at very low vehicle speeds, and therefore it does not actually allow simulation of vehicle running at arbitrarily variable speed. The simplified model of transient rolling, which involves calculation of the stress distribution in the discretised contact area, overcomes this disadvantage but might be unnecessarily complex for more simple simulations. In this paper, an approximative creep force computation method for transient rolling is presented. Its purpose is not to study the transient phenomena themselves but provide a simple and readily available way to prevent incorrect results of the numerical simulation when the vehicle speed approaches zero. The proper function of the proposed method is demonstrated by a simulation of start-up and interrupted sliding of a four-axle locomotive.

  19. Characterization of Hop-and-Sink Locomotion of Water Fleas

    Science.gov (United States)

    Skipper, A. N.; Murphy, D. W.; Webster, D. R.

    2017-11-01

    The freshwater crustacean Daphnia magna is a widely studied zooplankton in relation to food webs, predator-prey interactions, and other biological/ecological considerations; however, their locomotion is poorly quantified and understood. These water fleas utilize a hop-and-sink mechanism that consists of making quick, impulsive jumps by beating their antennae to propel themselves forward (roughly 1 body length). The animals then sink for a period, during which they stretch out their antennae to increase drag and thereby reduce their sinking velocity. Time-resolved three-dimensional flow fields surrounding the animals were quantified with a unique infrared tomographic particle image velocimetry (tomo-PIV) system. Three-dimensional kinematics data were also extracted from the image sequences. In the current work, we compared body kinematics and flow disturbance among organisms of size in the range of 1.3 to 2.8 mm. The stroke cycle averaged 150 +/- 20 ms, with each stroke cycle split nearly evenly between power and recovery strokes. The kinematics data collapsed onto a self-similar curve when properly nondimensionalized, and a general trend was shown to exist between the nondimensionalized peak body speed and body length. The fluid flow induced by each antennae consisted of a viscous vortex ring that demonstrated a slow decay in the wake. The viscous dissipation showed no clear dependence on body size, whereas the volume of fluid exceeding 5 mm/s (the speed near the sinking speed of the animal) decayed more slowly with increasing body size.

  20. Integrated diversification of locomotion and feeding in labrid fishes.

    Science.gov (United States)

    Collar, David C; Wainwright, Peter C; Alfaro, Michael E

    2008-02-23

    An organism's performance of any ecological task involves coordination of multiple functional systems. Feeding performance is influenced by locomotor abilities which are used during search and capture of prey, as well as cranial mechanics, which affect prey capture and processing. But, does this integration of functional systems manifest itself during evolution? We asked whether the locomotor and feeding systems evolved in association in one of the most prominent and diverse reef fish radiations, the Labridae. We examined features of the pectoral fins that affect swimming performance and aspects of the skull that describe force and motion of the jaws. We applied a recent phylogeny, calculated independent contrasts for 60 nodes and performed principal components analyses separately on contrasts for fin and skull traits. The major axes of fin and skull diversification are highly correlated; modifications of the skull to amplify the speed of jaw movements are correlated with changes in the pectoral fins that increase swimming speed, and increases in force capacity of the skull are associated with changes towards fins that produce high thrust at slow speeds. These results indicate that the labrid radiation involved a strong connection between locomotion and feeding abilities.

  1. Mathematical modeling and simulation of aquatic and aerial animal locomotion

    Science.gov (United States)

    Hou, T. Y.; Stredie, V. G.; Wu, T. Y.

    2007-08-01

    In this paper, we investigate the locomotion of fish and birds by applying a new unsteady, flexible wing theory that takes into account the strong nonlinear dynamics semi-analytically. We also make extensive comparative study between the new approach and the modified vortex blob method inspired from Chorin's and Krasny's work. We first implement the modified vortex blob method for two examples and then discuss the numerical implementation of the nonlinear analytical mathematical model of Wu. We will demonstrate that Wu's method can capture the nonlinear effects very well by applying it to some specific cases and by comparing with the experiments available. In particular, we apply Wu's method to analyze Wagner's result for a wing abruptly undergoing an increase in incidence angle. Moreover, we study the vorticity generated by a wing in heaving, pitching and bending motion. In both cases, we show that the new method can accurately represent the vortex structure behind a flying wing and its influence on the bound vortex sheet on the wing.

  2. Switching Phenomena in a System with No Switches

    Science.gov (United States)

    Preis, Tobias; Stanley, H. Eugene

    2010-02-01

    It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

  3. Full-scale locomotive dynamic crash testing and correlations : C-39 type locomotive colliding with a loaded hopper car (test 7).

    Science.gov (United States)

    2011-09-01

    This report presents the results of a locomotive and three loaded hopper car consist traveling at 29 miles per hour colliding with a stationary consist of 35 loaded hopper cars. The details of test instrumentation, LS-DYNA finite element simulation, ...

  4. DETERMINANT OF DOWNWARD AUDITOR SWITCHING

    Directory of Open Access Journals (Sweden)

    Totok Budisantoso

    2017-12-01

    Full Text Available Abstract: Determinant of Downward Auditor Switching. This study examines the factors that influence downward auditor switching in five ASEAN countries. Fixed effect logistic regression was used as analytical method. This study found that opinion shopping occurred in ASEAN, especially in distress companies. Companies with complex businesses will retain the Big Four auditors to reduce complexity and audit costs. Audit and public committees serve as guardians of auditor quality. On the other hand, shareholders failed to maintain audit quality. It indicates that there is entrenchment effect in auditor switching.

  5. Electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.

    1997-10-01

    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.

  6. Biomechanics of the Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    DeWitt, John; Cromwell, R. L.; Ploutz-Snyder, L. L.

    2014-01-01

    Exercise prescriptions completed by International Space Station (ISS) crewmembers are typically based upon evidence obtained during ground-based investigations, with the assumption that the results of long-term training in weightlessness will be similar to that attained in normal gravity. Coupled with this supposition are the assumptions that exercise motions and external loading are also similar between gravitational environments. Normal control of locomotion is dependent upon learning patterns of muscular activation and requires continual monitoring of internal and external sensory input [1]. Internal sensory input includes signals that may be dependent on or independent of gravity. Bernstein hypothesized that movement strategy planning and execution must include the consideration of segmental weights and inertia [2]. Studies of arm movements in microgravity showed that individuals tend to make errors but that compensation strategies result in adaptations, suggesting that control mechanisms must include peripheral information [3-5]. To date, however, there have been no studies examining a gross motor activity such as running in weightlessness other than using microgravity analogs [6-8]. The objective of this evaluation was to collect biomechanical data from crewmembers during treadmill exercise before and during flight. The goal was to determine locomotive biomechanics similarities and differences between normal and weightless environments. The data will be used to optimize future exercise prescriptions. This project addresses the Critical Path Roadmap risks 1 (Accelerated Bone Loss and Fracture Risk) and 11 (Reduced Muscle Mass, Strength, and Endurance). Data were collected from 7 crewmembers before flight and during their ISS missions. Before launch, crewmembers performed a single data collection session at the NASA Johnson Space Center. Three-dimensional motion capture data were collected for 30 s at speeds ranging from 1.5 to 9.5 mph in 0.5 mph increments

  7. Impact of food restriction and cocaine on locomotion in ghrelin- and ghrelin-receptor knockout mice.

    Science.gov (United States)

    Clifford, Shane; Zeckler, Rosie Albarran; Buckman, Sam; Thompson, Jeff; Hart, Nigel; Wellman, Paul J; Smith, Roy G

    2011-07-01

    Food restriction (FR) augments the behavioral and reinforcing effects of psychomotor stimulants such as cocaine or amphetamine; effects that may be related to the capacity of FR to increase plasma levels of ghrelin (GHR), a 28-amino acid orexigenenic peptide linked to activation of brain dopamine systems. The present study used wild-type (WT) mice or mutant mice sustaining knockout of either GHR [GHR((-/-)) ] or of the growth hormone secretagogue receptor [GHS-R((-/-)) ] and subjected to FR or not to evaluate the role of GHR and GHS-R in cocaine-stimulated locomotion. WT, GHR((-/-)) , and GHS-R((-/-)) mice were either restricted to 60% of baseline caloric intake or allowed to free-feed (FF). Mice were treated with 0, 1.25, 2.5 and 5.0 mg/kg cocaine on separate test days (in random dose order) and forward locomotion was recorded on each drug day for 45 minutes after drug dosing. Food (and water) was available immediately after (but not during) each activity test. For FF mice, there was no interaction between cocaine and GHR status on locomotion. FR-WT mice treated with saline exhibited significant increases in anticipatory locomotion (relative to FF-WT mice), whereas FR-GHS-R((-/-)) mice did not. Cocaine significantly increased locomotion in FR-GHR((-/-)) and FR-GHS-R((-/-)) mice to the levels noted in FR-WT mice. These results suggest that GHS-R activity, but not GHR activity, is required for FR to augment food-associated anticipatory locomotion, but do not support the contention that GHR pathways are required for the capacity of FR to augment the acute effect of cocaine on locomotion. © 2010 The Authors, Addiction Biology © 2010 Society for the Study of Addiction.

  8. Experiments on vibration-driven stick-slip locomotion: A sliding bifurcation perspective

    Science.gov (United States)

    Du, Zhouwei; Fang, Hongbin; Zhan, Xiong; Xu, Jian

    2018-05-01

    Dry friction appears at the contact interface between two surfaces and is the source of stick-slip vibrations. Instead of being a negative factor, dry friction is essential for vibration-driven locomotion system to take effect. However, the dry-friction-induced stick-slip locomotion has not been fully understood in previous research, especially in terms of experiments. In this paper, we experimentally study the stick-slip dynamics of a vibration-driven locomotion system from a sliding bifurcation perspective. To this end, we first design and build a vibration-driven locomotion prototype based on an internal piezoelectric cantilever. By utilizing the mechanical resonance, the small piezoelectric deformation is significantly amplified to drive the prototype to achieve effective locomotion. Through identifying the stick-slip characteristics in velocity histories, we could categorize the system's locomotion into four types and obtain a stick-slip categorization diagram. In each zone of the diagram the locomotion exhibits qualitatively different stick-slip dynamics. Such categorization diagram is actually a sliding bifurcation diagram; crossing from one stick-slip zone to another corresponds to the triggering of a sliding bifurcation. In addition, a simplified single degree-of-freedom model is established, with the rationality of simplification been explained theoretically and numerically. Based on the equivalent model, a numerical stick-slip categorization is also obtained, which shows good agreement with the experiments both qualitatively and quantitatively. To the best of our knowledge, this is the first work that experimentally generates a sliding bifurcation diagram. The obtained stick-slip categorizations deepen our understanding of stick-slip dynamics in vibration-driven systems and could serve as a base for system design and optimization.

  9. On the Role of the Pedunculopontine Nucleus and Mesencephalic Reticular Formation in Locomotion in Nonhuman Primates.

    Science.gov (United States)

    Goetz, Laurent; Piallat, Brigitte; Bhattacharjee, Manik; Mathieu, Hervé; David, Olivier; Chabardès, Stéphan

    2016-05-04

    The mesencephalic reticular formation (MRF) is formed by the pedunculopontine and cuneiform nuclei, two neuronal structures thought to be key elements in the supraspinal control of locomotion, muscle tone, waking, and REM sleep. The role of MRF has also been advocated in modulation of state of arousal leading to transition from wakefulness to sleep and it is further considered to be a main player in the pathophysiology of gait disorders seen in Parkinson's disease. However, the existence of a mesencephalic locomotor region and of an arousal center has not yet been demonstrated in primates. Here, we provide the first extensive electrophysiological mapping of the MRF using extracellular recordings at rest and during locomotion in a nonhuman primate (NHP) (Macaca fascicularis) model of bipedal locomotion. We found different neuronal populations that discharged according to a phasic or a tonic mode in response to locomotion, supporting the existence of a locomotor neuronal circuit within these MRF in behaving primates. Altogether, these data constitute the first electrophysiological characterization of a locomotor neuronal system present within the MRF in behaving NHPs under normal conditions, in accordance with several studies done in different experimental animal models. We provide the first extensive electrophysiological mapping of the two major components of the mesencephalic reticular formation (MRF), namely the pedunculopontine and cuneiform nuclei. We exploited a nonhuman primate (NHP) model of bipedal locomotion with extracellular recordings in behaving NHPs at rest and during locomotion. Different MRF neuronal groups were found to respond to locomotion, with phasic or tonic patterns of response. These data constitute the first electrophysiological evidences of a locomotor neuronal system within the MRF in behaving NHPs. Copyright © 2016 the authors 0270-6474/16/364917-13$15.00/0.

  10. Phalangeal joints kinematics during ostrich (Struthio camelus locomotion

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2017-01-01

    Full Text Available The ostrich is a highly cursorial bipedal land animal with a permanently elevated metatarsophalangeal joint supported by only two toes. Although locomotor kinematics in walking and running ostriches have been examined, these studies have been largely limited to above the metatarsophalangeal joint. In this study, kinematic data of all major toe joints were collected from gaits with double support (slow walking to running during stance period in a semi-natural setup with two selected cooperative ostriches. Statistical analyses were conducted to investigate the effect of locomotor gait on toe joint kinematics. The MTP3 and MTP4 joints exhibit the largest range of motion whereas the first phalangeal joint of the 4th toe shows the largest motion variability. The interphalangeal joints of the 3rd and 4th toes present very similar motion patterns over stance phases of slow walking and running. However, the motion patterns of the MTP3 and MTP4 joints and the vertical displacement of the metatarsophalangeal joint are significantly different during running and slow walking. Because of the biomechanical requirements, osctriches are likely to select the inverted pendulum gait at low speeds and the bouncing gait at high speeds to improve movement performance and energy economy. Interestingly, the motions of the MTP3 and MTP4 joints are highly synchronized from slow to fast locomotion. This strongly suggests that the 3rd and 4th toes really work as an “integrated system” with the 3rd toe as the main load bearing element whilst the 4th toe as the complementary load sharing element with a primary role to ensure the lateral stability of the permanently elevated metatarsophalangeal joint.

  11. Effects of sounds of locomotion on speech perception

    Directory of Open Access Journals (Sweden)

    Matz Larsson

    2015-01-01

    Full Text Available Human locomotion typically creates noise, a possible consequence of which is the masking of sound signals originating in the surroundings. When walking side by side, people often subconsciously synchronize their steps. The neurophysiological and evolutionary background of this behavior is unclear. The present study investigated the potential of sound created by walking to mask perception of speech and compared the masking produced by walking in step with that produced by unsynchronized walking. The masking sound (footsteps on gravel and the target sound (speech were presented through the same speaker to 15 normal-hearing subjects. The original recorded walking sound was modified to mimic the sound of two individuals walking in pace or walking out of synchrony. The participants were instructed to adjust the sound level of the target sound until they could just comprehend the speech signal ("just follow conversation" or JFC level when presented simultaneously with synchronized or unsynchronized walking sound at 40 dBA, 50 dBA, 60 dBA, or 70 dBA. Synchronized walking sounds produced slightly less masking of speech than did unsynchronized sound. The median JFC threshold in the synchronized condition was 38.5 dBA, while the corresponding value for the unsynchronized condition was 41.2 dBA. Combined results at all sound pressure levels showed an improvement in the signal-to-noise ratio (SNR for synchronized footsteps; the median difference was 2.7 dB and the mean difference was 1.2 dB [P < 0.001, repeated-measures analysis of variance (RM-ANOVA]. The difference was significant for masker levels of 50 dBA and 60 dBA, but not for 40 dBA or 70 dBA. This study provides evidence that synchronized walking may reduce the masking potential of footsteps.

  12. Decoding bipedal locomotion from the rat sensorimotor cortex

    Science.gov (United States)

    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-10-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower limb movement from the motor cortex has received comparatively little attention. Here, we performed experiments to identify the type and amount of information that can be decoded from neuronal ensemble activity in the hindlimb area of the rat motor cortex during bipedal locomotor tasks. Approach. Rats were trained to stand, step on a treadmill, walk overground and climb staircases in a bipedal posture. To impose this gait, the rats were secured in a robotic interface that provided support against the direction of gravity and in the mediolateral direction, but behaved transparently in the forward direction. After completion of training, rats were chronically implanted with a micro-wire array spanning the left hindlimb motor cortex to record single and multi-unit activity, and bipolar electrodes into 10 muscles of the right hindlimb to monitor electromyographic signals. Whole-body kinematics, muscle activity, and neural signals were simultaneously recorded during execution of the trained tasks over multiple days of testing. Hindlimb kinematics, muscle activity, gait phases, and locomotor tasks were decoded using offline classification algorithms. Main results. We found that the stance and swing phases of gait and the locomotor tasks were detected with accuracies as robust as 90% in all rats. Decoded hindlimb kinematics and muscle activity exhibited a larger variability across rats and tasks. Significance. Our study shows that the rodent motor cortex contains useful information for lower limb neuroprosthetic development. However, brain-machine interfaces estimating gait phases or locomotor behaviors, instead of continuous variables such as limb joint positions or speeds

  13. High current vacuum closing switch

    International Nuclear Information System (INIS)

    Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

    2005-01-01

    The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

  14. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  15. Switching of chirality by light

    NARCIS (Netherlands)

    Feringa, B.L.; Schoevaars, A.M; Jager, W.F.; de Lange, B.; Huck, N.P.M.

    1996-01-01

    Optically active photoresponsive molecules are described by which control of chirality is achieved by light. These chiroptical molecular switches are based on inherently dissymmetric overcrowded alkenes and the synthesis, resolution and dynamic stereochemical properties are discussed. Introduction

  16. Aurora oil switch upgrade program

    International Nuclear Information System (INIS)

    Warren, T.

    1989-03-01

    This report describes the short pulse synchronization requirements, the original Aurora trigger scheme, and the PI/SNLA approach to improving the synchronization. It also describes the oil switching design study undertaken as the first phase of the program. A discussion of oil-switch closure analysis and the conceptual design motivated by this analysis are presented. This paper also describes the oil-switch trigger pulser tests required to validate the concept. This includes the design of the testing facility, a description of the test goals, and a discussion of the results. This paper finally describes oil-switch trigger pulser testing on one of the four Aurora Blumlein modules, which includes the hardware design and operation, the testing goals, hardware installation, and test results. 9 refs., 26 figs

  17. Solid state bistable power switch

    Science.gov (United States)

    Bartko, J.; Shulman, H.

    1970-01-01

    Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion.

  18. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing; Cha, Dong Kyu; Bosman, Michel; Raghavan, Nagarajan; Migas, Dmitri B.; Borisenko, Victor E.; Zhang, Xixiang; Li, Kun; Pey, Kin-Leong

    2013-01-01

    -chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission

  19. Electron collisions in gas switches

    International Nuclear Information System (INIS)

    Christophorou, L.G.

    1989-01-01

    Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

  20. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  1. High PRF high current switch

    Science.gov (United States)

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  2. Chromatic interocular-switch rivalry.

    Science.gov (United States)

    Christiansen, Jens H; D'Antona, Anthony D; Shevell, Steven K

    2017-05-01

    Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses.

  3. Locomotion mode identification for lower limbs using neuromuscular and joint kinematic signals.

    Science.gov (United States)

    Afzal, Taimoor; White, Gannon; Wright, Andrew B; Iqbal, Kamran

    2014-01-01

    Recent development in lower limb prosthetics has seen an emergence of powered prosthesis that have the capability to operate in different locomotion modes. However, these devices cannot transition seamlessly between modes such as level walking, stair ascent and descent and up slope and down slope walking. They require some form of user input that defines the human intent. The purpose of this study was to develop a locomotion mode detection system and evaluate its performance for different sensor configurations and to study the effect of locomotion mode detection with and without electromyography (EMG) signals while using kinematic data from hip joint of non-dominant/impaired limb and an accelerometer. Data was collected from four able bodied subjects that completed two circuits that contained standing, level-walking, ramp ascent and descent and stair ascent and descent. By using only the kinematic data from the hip joint and accelerometer data the system was able to identify the transitions, stance and swing phases with similar performance as compared to using only EMG and accelerometer data. However, significant improvement in classification error was observed when EMG, kinematic and accelerometer data were used together to identify the locomotion modes. The higher recognition rates when using the kinematic data along with EMG shows that the joint kinematics could be beneficial in intent recognition systems of locomotion modes.

  4. Walking like dinosaurs: chickens with artificial tails provide clues about non-avian theropod locomotion.

    Science.gov (United States)

    Grossi, Bruno; Iriarte-Díaz, José; Larach, Omar; Canals, Mauricio; Vásquez, Rodrigo A

    2014-01-01

    Birds still share many traits with their dinosaur ancestors, making them the best living group to reconstruct certain aspects of non-avian theropod biology. Bipedal, digitigrade locomotion and parasagittal hindlimb movement are some of those inherited traits. Living birds, however, maintain an unusually crouched hindlimb posture and locomotion powered by knee flexion, in contrast to the inferred primitive condition of non-avian theropods: more upright posture and limb movement powered by femur retraction. Such functional differences, which are associated with a gradual, anterior shift of the centre of mass in theropods along the bird line, make the use of extant birds to study non-avian theropod locomotion problematic. Here we show that, by experimentally manipulating the location of the centre of mass in living birds, it is possible to recreate limb posture and kinematics inferred for extinct bipedal dinosaurs. Chickens raised wearing artificial tails, and consequently with more posteriorly located centre of mass, showed a more vertical orientation of the femur during standing and increased femoral displacement during locomotion. Our results support the hypothesis that gradual changes in the location of the centre of mass resulted in more crouched hindlimb postures and a shift from hip-driven to knee-driven limb movements through theropod evolution. This study suggests that, through careful experimental manipulations during the growth phase of ontogeny, extant birds can potentially be used to gain important insights into previously unexplored aspects of bipedal non-avian theropod locomotion.

  5. A novel device for studying weight supported, quadrupedal overground locomotion in spinal cord injured rats.

    Science.gov (United States)

    Hamlin, Marvin; Traughber, Terence; Reinkensmeyer, David J; de Leon, Ray D

    2015-05-15

    Providing weight support facilitates locomotion in spinal cord injured animals. To control weight support, robotic systems have been developed for treadmill stepping and more recently for overground walking. We developed a novel device, the body weight supported ambulatory rodent trainer (i.e. BART). It has a small pneumatic cylinder that moves along a linear track above the rat. When air is supplied to the cylinder, the rats are lifted as they perform overground walking. We tested the BART device in rats that received a moderate spinal cord contusion injury and in normal rats. Locomotor training with the BART device was not performed. All of the rats learned to walk in the BART device. In the contused rats, significantly greater paw dragging and dorsal stepping occurred in the hindlimbs compared to normal. Providing weight support significantly raised hip position and significantly reduced locomotor deficits. Hindlimb stepping was tightly coupled to forelimb stepping but only when the contused rats stepped without weight support. Three weeks after the contused rats received a complete spinal cord transection, significantly fewer hindlimb steps were performed. Relative to rodent robotic systems, the BART device is a simpler system for studying overground locomotion. The BART device lacks sophisticated control and sensing capability, but it can be assembled relatively easily and cheaply. These findings suggest that the BART device is a useful tool for assessing quadrupedal, overground locomotion which is a more natural form of locomotion relative to treadmill locomotion. Published by Elsevier B.V.

  6. Quasi-dynamic walk of a quadruped locomotion robot using optimal tracking control

    International Nuclear Information System (INIS)

    Uchida, Hiroaki; Nonami, Kenzo; Chiba, Yasunori; Koyama, Kakutaro.

    1994-01-01

    Recently, many research works of quadruped locomotion robots, which are considered to be operable on irregular terrain, have been carried out. In the case of realizing ideal motion control of the quadruped locomotion robot, it is assumed that hierarchical cooperative control consisting of decentralized control and centralized control is desirable. In the case that the locomotion robot moves at high speed, it is impossible to follow the desired trajectory because using only the feedback control method includes time delay. It is known that feedforward control input is valid for such motion control. In this paper, decentralized control is realized to apply optimal tracking control using feedforward control input to the quadruped locomotion robot, as the first step. As a result, it is determined that the angle variation of the foot and the stride applying optimal tracking control input are large compared with using only feedback control. It is verified that feedforward control input is useful to control the trajectory of the tip of the foot in high speed locomotion. (author)

  7. Walking like dinosaurs: chickens with artificial tails provide clues about non-avian theropod locomotion.

    Directory of Open Access Journals (Sweden)

    Bruno Grossi

    Full Text Available Birds still share many traits with their dinosaur ancestors, making them the best living group to reconstruct certain aspects of non-avian theropod biology. Bipedal, digitigrade locomotion and parasagittal hindlimb movement are some of those inherited traits. Living birds, however, maintain an unusually crouched hindlimb posture and locomotion powered by knee flexion, in contrast to the inferred primitive condition of non-avian theropods: more upright posture and limb movement powered by femur retraction. Such functional differences, which are associated with a gradual, anterior shift of the centre of mass in theropods along the bird line, make the use of extant birds to study non-avian theropod locomotion problematic. Here we show that, by experimentally manipulating the location of the centre of mass in living birds, it is possible to recreate limb posture and kinematics inferred for extinct bipedal dinosaurs. Chickens raised wearing artificial tails, and consequently with more posteriorly located centre of mass, showed a more vertical orientation of the femur during standing and increased femoral displacement during locomotion. Our results support the hypothesis that gradual changes in the location of the centre of mass resulted in more crouched hindlimb postures and a shift from hip-driven to knee-driven limb movements through theropod evolution. This study suggests that, through careful experimental manipulations during the growth phase of ontogeny, extant birds can potentially be used to gain important insights into previously unexplored aspects of bipedal non-avian theropod locomotion.

  8. CONTROL OF BOUNCING IN RF MEMS SWITCHES USING DOUBLE ELECTRODE

    KAUST Repository

    Abdul Rahim, Farhan

    2014-01-01

    MEMS based mechanical switches are seen to be the likely replacements for CMOS based switches due to the several advantages that these mechanical switches have over CMOS switches. Mechanical switches can be used in systems under extreme conditions

  9. Switched capacitor DC-DC converter with switch conductance modulation and Pesudo-fixed frequency control

    DEFF Research Database (Denmark)

    Larsen, Dennis Øland; Vinter, Martin; Jørgensen, Ivan Harald Holger

    A switched capacitor dc-dc converter with frequency-planned control is presented. By splitting the output stage switches in eight segments the output voltage can be regulated with a combination of switching frequency and switch conductance. This allows for switching at predetermined frequencies, 31...

  10. A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

    Science.gov (United States)

    Gollan, Tamar H.; Goldrick, Matthew

    2018-01-01

    The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

  11. Musculoskeletal modelling of an ostrich (Struthio camelus pelvic limb: influence of limb orientation on muscular capacity during locomotion

    Directory of Open Access Journals (Sweden)

    John R. Hutchinson

    2015-06-01

    Full Text Available We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g., weighting of muscle force–length or force–velocity properties in selecting postures. This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model’s results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our

  12. TRANSPORT LOCOMOTIVE AND WASTE PACKAGE TRANSPORTER ITS STANDARDS IDENTIFICATION STUDY

    International Nuclear Information System (INIS)

    Draper, K.D.

    2005-01-01

    To date, the project has established important to safety (ITS) performance requirements for structures, systems and components (SSCs) based on identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the ''Nuclear Safety Design Basis for License Application'' (NSDB) (BSC 2005). Further, SSCs credited with performing safe functions are classified as ITS. In turn, performance confirmation for these SSCs is sought through the use of consensus code and standards. The purpose of this study is to identify applicable codes and standards for the waste package (WP) transporter and transport locomotive ITS SSCs. Further, this study will form the basis for selection and the extent of applicability of each code and standard. This study is based on the design development completed for License Application only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and that final selection will not be determined until further design development has occurred. Therefore, for completeness, throughout this study alternative designs currently under consideration will be discussed. Further, the results of this study will be subject to evaluation as part of a follow-on gap analysis study. Based on the results of this study the gap analysis will evaluate each code and standard to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied a ''gap'' is highlighted. Thereafter, the study will identify supplemental requirements to augment the code or standard to meet performance requirements. Further, the gap analysis will identify non-standard areas of the design that will be subject to a Development Plan. Non-standard components and

  13. Bipedal locomotion of bonnet macaques after spinal cord injury.

    Science.gov (United States)

    Babu, Rangasamy Suresh; Anand, P; Jeraud, Mathew; Periasamy, P; Namasivayam, A

    2007-10-01

    Experimental studies concerning the analysis of locomotor behavior in spinal cord injury research are widely performed in rodent models. The purpose of this study was to quantitatively evaluate the degree of functional recovery in reflex components and bipedal locomotor behavior of bonnet macaques (Macaca radiata) after spinal contusive injury. Six monkeys were tested for various reflex components (grasping, righting, hopping, extension withdrawal) and were trained preoperatively to walk in bipedal fashion on the simple and complex locomotor runways (narrow beam, grid, inclined plane, treadmill) of this investigation. The overall performance of the animals'motor behavior and the functional status of limb movements during bipedal locomotion were graded by the Combined Behavioral Score (CBS) system. Using the simple Allen weight-drop technique, a contusive injury was produced by dropping a 13-g weight from a height of 30 cm to the exposed spinal cord at the T12-L1 vertebral level of the trained monkeys. All the monkeys showed significant impairments in every reflex activity and in walking behavior during the early part of the postoperative period. In subsequent periods, the animals displayed mild alterations in certain reflex responses, such as grasping, extension withdrawal, and placing reflexes, which persisted through a 1-year follow-up. The contused animals traversed locomotor runways--narrow beam, incline plane, and grid runways--with more steps and few errors, as evaluated with the CBS system. Eventually, the behavioral performance of all spinal-contused monkeys recovered to near-preoperative level by the fifth postoperative month. The findings of this study reveal the recovery time course of various reflex components and bipedal locomotor behavior of spinal-contused macaques on runways for a postoperative period of up to 1 year. Our spinal cord research in primates is advantageous in understanding the characteristics of hind limb functions only, which possibly

  14. Mechatronics by Analogy and Application to Legged Locomotion

    Science.gov (United States)

    Ragusila, Victor

    determined, the original mechanism is optimized such that its dynamic behaviour is analogous. It is shown that, if this analogy is achieved, the control system designed based on the simpler mechanisms can be directly implemented to the more complex system, and their dynamic behaviours are close enough for the system performance to be effectively the same. Finally it is shown that, for the employed objective of fast legged locomotion, the proposed methodology achieves a better design than Reduction-by-Feedback, a competing methodology that uses control layers to simplify the dynamics of the system.

  15. Principles of broadband switching and networking

    CERN Document Server

    Liew, Soung C

    2010-01-01

    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  16. MATHEMATIC SIMULATION OF TRANSIENT PROCESS IN A.C. – SYSTEM “ELECTRIC TRACTION NETWORK – LOCOMOTIVE” 1. SWITCH ON LOCOMOTIVE’S POWER CONVERTER IN “FREE PLAY” MODE; PARAMETERS ESTIMATION

    Directory of Open Access Journals (Sweden)

    T. M. Mishchenko

    2010-11-01

    Full Text Available In the article the electric circuit of substitution and mathematical model of the system of alternating current «traction substation − traction mains − electric locomotive DS 3» at switching its power transformer on in the idle mode are presented. Numerical determinations of parameters of traction substation, rails, contact network and transformer are executed; in so doing a special attention is paid to the estimation of dispersion inductance for the primary winding of transformer.

  17. MATHEMATIC SIMULATION OF TRANSIENT PROCESS IN A.C. – SYSTEM “ELECTRIC TRACTION NETWORK – LOCOMOTIVE” 1. SWITCH ON LOCOMOTIVE’S POWER CONVERTER IN “FREE PLAY” MODE; PARAMETERS ESTIMATION

    OpenAIRE

    T. M. Mishchenko; A. I. Kiiko

    2010-01-01

    In the article the electric circuit of substitution and mathematical model of the system of alternating current «traction substation − traction mains − electric locomotive DS 3» at switching its power transformer on in the idle mode are presented. Numerical determinations of parameters of traction substation, rails, contact network and transformer are executed; in so doing a special attention is paid to the estimation of dispersion inductance for the primary winding of transformer.

  18. Bombardier extends its TRAXX locomotive family; Bombardier erweitert seine Lokomotivfamilie TRAXX

    Energy Technology Data Exchange (ETDEWEB)

    Vitins, J. [Bombardier, Zuerich (Switzerland)

    2005-07-01

    Bombardier has extended and optimised its TRAXX locomotive platform, launched in 2003, with the addition of a multi-system locomotive and the introduction of technical innovations. The developments centre on the multi-system loco TRAXX F140 MS, which gained approval in a very short space of time and is already being successfully operated by SBB as type Re 484 for freight traffic between Switzerland and Italy; the TRAXX F140 DC, recently ordered by Angel Trains Cargo for Italy's DC network, and the 2nd series of the proven AC loco TRAXX AC2, operated by Railion in Germany as type BR 185.2. All these locomotive types reflect the development work undertaken with a view to accommodating the various national train protection systems through the new ETCS-compatible Bombardier ATP (Automatic Train Protection) system, together with chopper-controlled power conversion in DC networks. (orig.)

  19. Switching dynamics of TaOx-based threshold switching devices

    Science.gov (United States)

    Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

    2018-03-01

    Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

  20. Different performances in static and dynamic imagery and real locomotion. An exploratory trial.

    Directory of Open Access Journals (Sweden)

    Augusto eFusco

    2014-10-01

    Full Text Available Motor imagery is a mental representation of an action without its physical execution. Recently, the simultaneous movement of the body has been added to the mental simulation. This refers to dynamic motor imagery (dMI. This study was aimed at analyzing the temporal features for static and dMI in different locomotor conditions (natural walking, NW, light running, LR, lateral walking, LW, backward walking, BW, and whether these performances were more related to all the given conditions or present only in walking. We have been also evaluated the steps performed in the dMI in comparison with the ones performed by real locomotion. Twenty healthy participants (29.3 ± 5.1 y. old were asked to move towards a visualized target located at 10mt. In dMI, no significant temporal differences respect the actual locomotion were found for all the given tasks (NW: p=0.058, LR: p=0.636, BW: p=0.096; LW: p=0,487. Significant temporal differences between static imagery and actual movements were found for LR (p<0.001 and LW (p<0.001, due to an underestimation of time needed to achieve the target in imagined locomotion. Significant differences in terms of number of steps among tasks were found for LW (p<0.001 and BW (p=0.036, whereas neither in NW (p=0.124 nor LR (p=0.391 between dMI and real locomotion.Our results confirmed that motor imagery is a task-dependent process, with walking being temporally closer than other locomotor conditions. Moreover, the time records of dynamic motor imagery are nearer to the ones of actual locomotion respect than the ones of static motor imagery. Keywords: Walking, dynamic motor imagery, human locomotion, chronometry.

  1. IGBT: a solid state switch

    International Nuclear Information System (INIS)

    Chatroux, D.; Maury, J.; Hennevin, B.

    1993-01-01

    A Copper Vapour Laser Power Supply has been designed using a solid state switch consisting in eighteen Isolated Gate Bipolar Transistors (IGBT), -1200 volts, 400 Amps, each-in parallel. This paper presents the Isolated Gate Bipolar Transistor (IGBTs) replaced in the Power Electronic components evolution, and describes the IGBT conduction mechanism, presents the parallel association of IGBTs, and studies the application of these components to a Copper Vapour Laser Power Supply. The storage capacitor voltage is 820 volts, the peak current of the solid state switch is 17.000 Amps. The switch is connected on the primary of a step-up transformer, followed by a magnetic modulator. The reset of the magnetic modulator is provided by part of the laser reflected energy with a patented circuit. The charging circuit is a resonant circuit with a charge controlled by an IGBT switch. When the switch is open, the inductance energy is free-wheeled by an additional winding and does not extend the charging phase of the storage capacitor. The design allows the storage capacitor voltage to be very well regulated. This circuit is also patented. The electric pulse in the laser has 30.000 Volt peak voltage, 2000 Amp peak current, and is 200 nanoseconds long, for a 200 Watt optical power Copper Vapour Laser

  2. Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

    Science.gov (United States)

    Khusainov, R.; Klimchik, A.; Magid, E.

    2017-01-01

    The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

  3. Damages and resource of locomotive wheels used under the north operating conditions

    Directory of Open Access Journals (Sweden)

    A. V. Grigorev

    2014-01-01

    Full Text Available In operating railway equipment, in particular the elements, such as a wheel and a rail there is damage accumulation of any kind, causing a premature equipment failure. Thus, an analysis of the mechanisms and modeling of damage accumulation and fracture both on the surface and in the bulk material remain a challenge.Data on the defective wheel sets to be subjected to facing has been collected and analyzed to assess the locomotive wheel sets damage of the locomotive fleet company of AK «Yakutia Railways», city of Aldan, The Republic of Sakha (Yakutia. For this purpose, three main locomotives have been examined.The object of research carried out in this paper, is a locomotive wheels tire, which is subjected to cyclic impact (dynamic loads during operation. In this regard, the need arises to determine both the strength of material in response to such shock loads and the quantitative calculation of damage accumulated therein.The accumulated fatigue damage has been attributed to one radial cross section of the wheel coming into contact with the rail once per revolution of the wheel. Consequently, in one revolution a wheel is under one loading cycle. As stated, the average mileage of locomotives to have the unacceptable damages formed on the tread surface is 12 thousand km.Test results establish that along with the high-cycle loading the shock-contact action on rail joints significantly affects the accumulation of damage in the locomotive wheels tire. The number of cycles to failure due to the formation of unacceptable damage in the locomotive wheels tire is N = 2,4×106 and 6×105 cycles, respectively, for fatigue and shock-contact loading.In general, we can say that the problem of higher intensity to form the surface damage is directly related to the operation of the locomotive wheel tire under abnormally low climatic temperatures. With decreasing ambient temperature, this element material rapidly looses its plastic properties, thereby accelerating

  4. Three-dimensional Locomotion and Drilling Microrobot Using Electromagnetic Actuation System

    Energy Technology Data Exchange (ETDEWEB)

    Li, Girl; Choi, Hyun Chul; Cha, Kyoung Rae; Jeong, Se Mi; Park, Jong Oh; Park, Suk Ho [Chonnam National University, Gwangju (Korea, Republic of)

    2011-12-15

    In this study, a novel electromagnetic microrobot system with locomotion and drilling functions in three dimensional space was developed. Because of size limitations, the microrobot does not have actuator, battery, and controller. Therefore, an electromagnetic actuation (EMA) system was used to drive the robot. The proposed EMA system consists of three rectangular Helmholtz coil pairs in x-, y- and z-axes and a Maxwell coil pair in the z-axis. The magnetic field generated in the EMA coil system could be controlled by the input current of the EMA coil. Finally, through various experiments, the locomotion and drilling performances of the proposed EMA microrobot system were verified.

  5. Three-dimensional Locomotion and Drilling Microrobot Using Electromagnetic Actuation System

    International Nuclear Information System (INIS)

    Li, Girl; Choi, Hyun Chul; Cha, Kyoung Rae; Jeong, Se Mi; Park, Jong Oh; Park, Suk Ho

    2011-01-01

    In this study, a novel electromagnetic microrobot system with locomotion and drilling functions in three dimensional space was developed. Because of size limitations, the microrobot does not have actuator, battery, and controller. Therefore, an electromagnetic actuation (EMA) system was used to drive the robot. The proposed EMA system consists of three rectangular Helmholtz coil pairs in x-, y- and z-axes and a Maxwell coil pair in the z-axis. The magnetic field generated in the EMA coil system could be controlled by the input current of the EMA coil. Finally, through various experiments, the locomotion and drilling performances of the proposed EMA microrobot system were verified

  6. Peristaltic Wave Locomotion and Shape Morphing with a Millipede Inspired System

    Science.gov (United States)

    Spinello, Davide; Fattahi, Javad S.

    2017-08-01

    We present the mechanical model of a bio-inspired deformable system, modeled as a Timoshenko beam, which is coupled to a substrate by a system of distributed elements. The locomotion action is inspired by the coordinated motion of coupling elements that mimic the legs of millipedes and centipedes, whose leg-to-ground contact can be described as a peristaltic displacement wave. The multi-legged structure is crucial in providing redundancy and robustness in the interaction with unstructured environments and terrains. A Lagrangian approach is used to derive the governing equations of the system that couple locomotion and shape morphing. Features and limitations of the model are illustrated with numerical simulations.

  7. CONCENTRATION OF HARMFUL SUBSTANCES REDUCING IN SURFACE LAYER OF ATMOSPHERE AT RHEOSTAT LOCOMOTIVE TESTS

    Directory of Open Access Journals (Sweden)

    E. A. Bondar

    2010-06-01

    Full Text Available It is shown that at present an acceptable way of reducing the concentration of harmful substances in the surface layer of the atmosphere at rheostat tests of locomotives is their dispersion in a large volume of air. Channels, installed above an exhaust pipe of diesel locomotive with a break at the gas flow, work as ejectors. We have solved jointly the equation of aerodynamic characteristics of the ejector device and the equation of diffusion of gases; as a result the calculated dependence for determining the necessary height of ejector device has been obtained.

  8. Modelling of dynamically stable AR-601M robot locomotion in Simulink

    Directory of Open Access Journals (Sweden)

    Khusainov Ramil

    2016-01-01

    Full Text Available Humanoid robots will gradually play an important role in our daily lives. Currently, research on anthropomorphic robots and biped locomotion is one of the most important problems in the field of mobile robotics, and the development of reliable control algorithms for them is a challenging task. In this research two algorithms for stable walking of Russian anthropomorphic robot AR-601M with 41 Degrees of Freedom (DoF are investigated. To achieve a human-like dynamically stable locomotion 6 DoF in each robot leg are controlled with Virtual Height Inverted Pendulum and Preview control methods.

  9. 78 FR 33860 - Crawler, Locomotive, and Truck Cranes Standard; Extension of the Office of Management and Budget...

    Science.gov (United States)

    2013-06-05

    ...] Crawler, Locomotive, and Truck Cranes Standard; Extension of the Office of Management and Budget's (OMB... collection requirements contained in the General Industry Standard on Crawler, Locomotive, and Truck cranes... workers from using unsafe cranes and ropes, thereby reducing their risk of death or serious injury caused...

  10. 75 FR 20005 - Crawler, Locomotive, and Truck Cranes Standard; Extension of the Office of Management and Budget...

    Science.gov (United States)

    2010-04-16

    ...] Crawler, Locomotive, and Truck Cranes Standard; Extension of the Office of Management and Budget's (OMB... Crawler, Locomotive, and Truck Cranes Standard (29 CFR 1910.180). DATES: Comments must be submitted... of each of these requirements is to prevent workers from using unsafe cranes and ropes, thereby...

  11. USING THE INFORMATION OF ON-BOARD DIAGNOSTIC SYSTEMS IN DETERMINING THE TECHNICAL STATE OF THE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    B. Ye. Bodnar

    2008-12-01

    Full Text Available The issues of increase of efficiency of information processing by оn-board systems of diagnostics of locomotives are considered. The examples of information processing by the on-board system of diagnostics of electric locomotives DE1 are presented. The suggestions on improvement of systematization and processing of information by on-board systems of diagnostics are given.

  12. CMOS integrated switching power converters

    CERN Document Server

    Villar-Pique, Gerard

    2011-01-01

    This book describes the structured design and optimization of efficient, energy processing integrated circuits. The approach is multidisciplinary, covering the monolithic integration of IC design techniques, power electronics and control theory. In particular, this book enables readers to conceive, synthesize, design and implement integrated circuits with high-density high-efficiency on-chip switching power regulators. Topics covered encompass the structured design of the on-chip power supply, efficiency optimization, IC-compatible power inductors and capacitors, power MOSFET switches and effi

  13. All-fiber polarization switch

    Science.gov (United States)

    Knape, Harald; Margulis, Walter

    2007-03-01

    We report an all-fiber polarization switch made out of silica-based microstructured fiber suitable for Q-switching all-fiber lasers. Nanosecond high-voltage pulses are used to heat and expand an internal electrode to cause λ/2-polarization rotation in less than 10 ns for 1.5 μm light. The 10 cm long component has an experimentally measured optical insertion loss of 0.2 dB and a 0-10 kHz repetition frequency capacity and has been durability tested for more than 109 pulses.

  14. A level switch with a sound tube

    OpenAIRE

    赤池, 誠規

    2017-01-01

    Level switches are sensor with an electrical contact output at a specific liquid, powder or bulk level. Most of traditional level switches are not suitable for harsh environments. The level switch in this study connects a loudspeaker on top end of the sound tube. When liquid, powder or bulk closes bottom end of the sound tube, the level switch turns on. The level switch is suitable for harsh environments and easy to install. The aim of this study is to propose a level switch with a sound tube...

  15. Motor deficits following dorsal corticospinal tract transection in rats: voluntary versus skilled locomotion readouts

    Directory of Open Access Journals (Sweden)

    Lara Bieler

    2018-02-01

    The functional relevance of the dorsal CST in locomotion of rats is not as prominent as compared to in humans and thus challenging the motor execution is mandatory to reliably investigate CST function. A detailed analysis of voluntary walking using the CatWalk XT is not adequate to detect deficits following dorsal CST lesion in rats.

  16. Flexible Coupling of Respiration and Vocalizations with Locomotion and Head Movements in the Freely Behaving Rat

    Directory of Open Access Journals (Sweden)

    Joseph Andrews Alves

    2016-01-01

    Full Text Available Quadrupedal mammals typically synchronize their respiration with body movements during rhythmic locomotion. In the rat, fast respiration is coupled to head movements during sniffing behavior, but whether respiration is entrained by stride dynamics is not known. We recorded intranasal pressure, head acceleration, instantaneous speed, and ultrasonic vocalizations from male and female adult rats while freely behaving in a social environment. We used high-speed video recordings of stride to understand how head acceleration signals relate to locomotion and developed techniques to identify episodes of sniffing, walking, trotting, and galloping from the recorded variables. Quantitative analysis of synchrony between respiration and head acceleration rhythms revealed that respiration and locomotion movements were coordinated but with a weaker coupling than expected from previous work in other mammals. We have recently shown that rats behaving in social settings produce high rates of ultrasonic vocalizations during locomotion bouts. Accordingly, rats emitted vocalizations in over half of the respiratory cycles during fast displacements. We present evidence suggesting that emission of these calls disrupts the entrainment of respiration by stride. The coupling between these two variables is thus flexible, such that it can be overridden by other behavioral demands.

  17. Crucial advantages of tail use in the evolution of vertebrate terrestrial locomotion

    Science.gov (United States)

    Astley, Henry; McInroe, Benjamin; Kawano, Sandy; Blob, Rick; Goldman, Daniel

    In the invasion of terrestrial environment, the first tetrapods faced the challenge of locomotion on flowable substrates (e.g. sand and mud), sometimes oriented at inclines. Although the morphology of many early tetrapods is known, robotic studies have revealed that effective locomotion on these substrates also depends strongly upon kinematics; slight differences in movements of the same appendage can lead to success or failure. Using a model organism (the mudskipper) and a robotic physical model, we demonstrate how muscular tails provided critical locomotor advantages on granular substrates that the first invaders of land likely encountered. Mudskippers use their tails for additional propulsion with increasing frequency as the slope of the granular material increases, and the decline in locomotor performance with slope is shallower when the tail is used. Experiments with a robotic model of the mudskipper showed that, while the tail did not always provide a benefit to locomotion, use of the tail made the robot's performance more robust, achieving effective locomotion on a wider range of slopes, limb postures and foot placements. These results suggest that, rather than simply being an inert appendage, the tails of early tetrapods were vital to their first forays into terrestrial habitats.

  18. Emotion, Intent and Voluntary Movement in Children with Autism. an Example: The Goal Directed Locomotion

    Science.gov (United States)

    Longuet, Sophie; Ferrel-Chapus, Carole; Oreve, Marie-Joelle; Chamot, Jean-Marc; Vernazza-Martin, Sylvie

    2012-01-01

    This article focuses on the impact of intentionality on goal directed locomotion in healthy and autistic children. Closely linked with emotions and motivation, it is directly connected with movement planning. Is planning only preserved when the goal of the action appears motivating for healthy and autistic children? Is movement programming similar…

  19. Dynamic investigation of a locomotive with effect of gear transmissions under tractive conditions

    Science.gov (United States)

    Chen, Zaigang; Zhai, Wanming; Wang, Kaiyun

    2017-11-01

    Locomotive is used to drag trailers to move or supply the braking forces to slow the running speed of a train. The electromagnetic torque of the motor is always transmitted by the gear transmission system to the wheelset for generation of the tractive or braking forces at the wheel-rail contact interface. Consequently, gear transmission system is significant for power delivery of a locomotive. This paper develops a comprehensive locomotive-track vertical-longitudinal coupled dynamics model with dynamic effect of gear transmissions. This dynamics model enables considering the coupling interactions between the gear transmission motion, the vertical and the longitudinal motions of the vehicle, and the vertical vibration of the track structure. In this study, some complicated dynamic excitations, such as the gear time-varying mesh stiffness, nonlinear gear tooth backlash, the nonlinear wheel-rail normal contact force and creep force, and the rail vertical geometrical irregularity, are considered. Then, the dynamic responses of the locomotive under the tractive conditions are demonstrated by numerical simulations based on the established dynamics model and by experimental test. The developed dynamics model is validated by the good agreement between the experimental and the theoretical results. The calculated results reveal that the gear transmission system has strong dynamic interactions with the wheel-rail contact interface including both the vertical and the longitudinal motions, and it has negligible effect on the vibrations of the bogie frame and carbody.

  20. Quadrupedal Robot Locomotion: A Biologically Inspired Approach and Its Hardware Implementation

    Directory of Open Access Journals (Sweden)

    A. Espinal

    2016-01-01

    Full Text Available A bioinspired locomotion system for a quadruped robot is presented. Locomotion is achieved by a spiking neural network (SNN that acts as a Central Pattern Generator (CPG producing different locomotion patterns represented by their raster plots. To generate these patterns, the SNN is configured with specific parameters (synaptic weights and topologies, which were estimated by a metaheuristic method based on Christiansen Grammar Evolution (CGE. The system has been implemented and validated on two robot platforms; firstly, we tested our system on a quadruped robot and, secondly, on a hexapod one. In this last one, we simulated the case where two legs of the hexapod were amputated and its locomotion mechanism has been changed. For the quadruped robot, the control is performed by the spiking neural network implemented on an Arduino board with 35% of resource usage. In the hexapod robot, we used Spartan 6 FPGA board with only 3% of resource usage. Numerical results show the effectiveness of the proposed system in both cases.

  1. FPGA implementation of a configurable neuromorphic CPG-based locomotion controller.

    Science.gov (United States)

    Barron-Zambrano, Jose Hugo; Torres-Huitzil, Cesar

    2013-09-01

    Neuromorphic engineering is a discipline devoted to the design and development of computational hardware that mimics the characteristics and capabilities of neuro-biological systems. In recent years, neuromorphic hardware systems have been implemented using a hybrid approach incorporating digital hardware so as to provide flexibility and scalability at the cost of power efficiency and some biological realism. This paper proposes an FPGA-based neuromorphic-like embedded system on a chip to generate locomotion patterns of periodic rhythmic movements inspired by Central Pattern Generators (CPGs). The proposed implementation follows a top-down approach where modularity and hierarchy are two desirable features. The locomotion controller is based on CPG models to produce rhythmic locomotion patterns or gaits for legged robots such as quadrupeds and hexapods. The architecture is configurable and scalable for robots with either different morphologies or different degrees of freedom (DOFs). Experiments performed on a real robot are presented and discussed. The obtained results demonstrate that the CPG-based controller provides the necessary flexibility to generate different rhythmic patterns at run-time suitable for adaptable locomotion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Science.gov (United States)

    2010-10-01

    ... shall be securely fastened with bolts, rivets, or studs. (ii) Locomotives having Wootten type boilers... inches above outside edge of running boards, securely fastened with bolts, rivets, or studs. (c... inches in height, measured from the top of end sill, and securely fastened with bolts or rivets. (f...

  3. Refraction corrected calibration for aquatic locomotion research: application of Snell's law improves spatial accuracy

    NARCIS (Netherlands)

    Henrion, S.; Spoor, C.W.; Pieters, R.P.M.; Müller, U.K.; Leeuwen, van J.L.

    2015-01-01

    Images of underwater objects are distorted by refraction at the water–glass–air interfaces and these distortions can lead to substantial errors when reconstructing the objects' position and shape. So far, aquatic locomotion studies have minimized refraction in their experimental setups and used the

  4. Manual and automatic locomotion scoring systems in dairy cows: A review

    NARCIS (Netherlands)

    Schlageter-Tello, A.; Bokkers, E.A.M.; Groot Koerkamp, P.W.G.; Hertem, van T.; Viazzi, S.; Romanini Bites, E.; Halachmi, I.; Bahr, C.; Berckmans, D.; Lokhorst, K.

    2014-01-01

    The objective of this review was to describe, compare and evaluate agreement, reliability, and validity of manual and automatic locomotion scoring systems (MLSSs and ALSSs, respectively) used in dairy cattle lameness research. There are many different types of MLSSs and ALSSs. Twenty-five MLSSs were

  5. A Threefold Approach for Precise and Efficient Locomotion in Virtual Environments with Varying Accessibility

    DEFF Research Database (Denmark)

    Arnskov, Thomas; Elmholdt, Anders; Jensen, Kristian Hagemann

    2018-01-01

    This poster details the design and evaluation of Locomotion3 - a framework that allows users to freely alternate between real walking, walking-in-place (WIP), and a skateboard metaphor depending on whether navigation requires efficiency, precision, or both. The user study compared the framework t...

  6. Gaze Strategies in Skateboard Trick Jumps: Spatiotemporal Constraints in Complex Locomotion

    Science.gov (United States)

    Klostermann, André; Küng, Philip

    2017-01-01

    Purpose: This study aimed to further the knowledge on gaze behavior in locomotion by studying gaze strategies in skateboard jumps of different difficulty that had to be performed either with or without an obstacle. Method: Nine experienced skateboarders performed "Ollie" and "Kickflip" jumps either over an obstacle or over a…

  7. FIM imaging and FIMtrack: two new tools allowing high-throughput and cost effective locomotion analysis.

    Science.gov (United States)

    Risse, Benjamin; Otto, Nils; Berh, Dimitri; Jiang, Xiaoyi; Klämbt, Christian

    2014-12-24

    The analysis of neuronal network function requires a reliable measurement of behavioral traits. Since the behavior of freely moving animals is variable to a certain degree, many animals have to be analyzed, to obtain statistically significant data. This in turn requires a computer assisted automated quantification of locomotion patterns. To obtain high contrast images of almost translucent and small moving objects, a novel imaging technique based on frustrated total internal reflection called FIM was developed. In this setup, animals are only illuminated with infrared light at the very specific position of contact with the underlying crawling surface. This methodology results in very high contrast images. Subsequently, these high contrast images are processed using established contour tracking algorithms. Based on this, we developed the FIMTrack software, which serves to extract a number of features needed to quantitatively describe a large variety of locomotion characteristics. During the development of this software package, we focused our efforts on an open source architecture allowing the easy addition of further modules. The program operates platform independent and is accompanied by an intuitive GUI guiding the user through data analysis. All locomotion parameter values are given in form of csv files allowing further data analyses. In addition, a Results Viewer integrated into the tracking software provides the opportunity to interactively review and adjust the output, as might be needed during stimulus integration. The power of FIM and FIMTrack is demonstrated by studying the locomotion of Drosophila larvae.

  8. Development of quadruped walking locomotion gait generator using a hybrid method

    International Nuclear Information System (INIS)

    Jasni, F; Shafie, A A

    2013-01-01

    The earth, in many areas is hardly reachable by the wheeled or tracked locomotion system. Thus, walking locomotion system is becoming a favourite option for mobile robot these days. This is because of the ability of walking locomotion to move on the rugged and unlevel terrains. However, to develop a walking locomotion gait for a robot is not a simple task. Central Pattern Generator (CPGs) method is a biological inspired method that is introduced as a method to develop the gait for the walking robot recently to tackle the issue faced by the conventional method of pre-designed trajectory based method. However, research shows that even the CPG method do have some limitations. Thus, in this paper, a hybrid method that combines CPG and the pre-designed trajectory based method is introduced to develop a walking gait for quadruped walking robot. The 3-D foot trajectories and the joint angle trajectories developed using the proposed method are compared with the data obtained via the conventional method of pre-designed trajectory to confirm the performance

  9. Human locomotion through a multiple obstacle environment : Strategy changes as a result of visual field limitation

    NARCIS (Netherlands)

    Jansen, S.E.M.; Toet, A.; Werkhoven, P.J.

    2011-01-01

    This study investigated how human locomotion through an obstacle environment is influenced by visual field limitation. Participants were asked to walk at a comfortable pace to a target location while avoiding multiple vertical objects. During this task, they wore goggles restricting their visual

  10. Emotion Locomotion: Promoting the Emotional Health of Elementary School Children by Recognizing Emotions

    Science.gov (United States)

    McLachlan, Debra A.; Burgos, Teresa; Honeycutt, Holly K.; Linam, Eve H.; Moneymaker, Laura D.; Rathke, Meghan K.

    2009-01-01

    Emotion recognition is a critical life skill children need for mental health promotion to meet the complexities and challenges of growing up in the world today. Five nursing students and their instructor designed "Emotion Locomotion," a program for children ages 6-8 during a public health nursing practicum for an inner-city parochial school.…

  11. 78 FR 73824 - Subzones 247A and 247B, Authorization of Production Activity, GE Transportation, (Locomotives...

    Science.gov (United States)

    2013-12-09

    ... of Production Activity, GE Transportation, (Locomotives, Off-Highway Vehicles and Motors/Engines), Lawrence Park and Grove City, Pennsylvania On July 18, 2013, GE Transportation submitted a notification of proposed production activity to the Foreign-Trade Zones (FTZ) Board for its facilities within Subzones 247A...

  12. 40 CFR 1042.836 - Marine certification of locomotive remanufacturing systems.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Marine certification of locomotive remanufacturing systems. 1042.836 Section 1042.836 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES AND VESSELS Special Provisions for Remanufactured Marine Engines § 1042.836 Marine certification...

  13. Development of Independent Locomotion in Children with a Severe Visual Impairment

    Science.gov (United States)

    Hallemans, Ann; Ortibus, Els; Truijen, Steven; Meire, Francoise

    2011-01-01

    Locomotion of children and adults with a visual impairment (ages 1-44, n = 28) was compared to that of age-related individuals with normal vision (n = 60). Participants walked barefoot at preferred speed while their gait was recorded by a Vicon[R] system. Walking speed, heading angle, step frequency, stride length, step width, stance phase…

  14. Swimming at low Reynolds number: a beginners guide to undulatory locomotion

    Science.gov (United States)

    Cohen, Netta; Boyle, Jordan H.

    2010-03-01

    Undulatory locomotion is a means of self-propulsion that relies on the generation and propagation of waves along a body. As a mode of locomotion it is primitive and relatively simple, yet can be remarkably robust. No wonder then, that it is so prevalent across a range of biological scales from motile bacteria to gigantic prehistoric snakes. Key to understanding undulatory locomotion is the body's interplay with the physical environment, which the swimmer or crawler will exploit to generate propulsion, and in some cases, even to generate the underlying undulations. This review focuses by and large on undulators in the low Reynolds number regime, where the physics of the environment can be much more tractable. We review some key concepts and theoretical advances, as well as simulation tools and results applied to selected examples of biological swimmers. In particular, we extend the discussion to some simple cases of locomotion in non-Newtonian media as well as to small animals, in which the nervous system, motor control, body properties and the environment must all be considered to understand how undulations are generated and modulated. To conclude, we review recent progress in microrobotic undulators that may one day become commonplace in applications ranging from toxic waste disposal to minimally invasive surgery.

  15. Industry switching in developing countries

    DEFF Research Database (Denmark)

    Newman, Carol; Rand, John; Tarp, Finn

    2013-01-01

    Firm turnover (i.e., firm entry and exit) is a well-recognized source of sector-level productivity growth. In contrast, the role and importance of firms that switch activities from one sector to another is not well understood. Firm switchers are likely to be unique, differing from both newly esta...

  16. Nanoscale organic ferroelectric resistive switches

    NARCIS (Netherlands)

    Khikhlovskyi, V.; Wang, R.; Breemen, A.J.J.M. van; Gelinck, G.H.; Janssen, R.A.J.; Kemerink, M.

    2014-01-01

    Organic ferroelectric resistive switches function by grace of nanoscale phase separation in a blend of a semiconducting and a ferroelectric polymer that is sandwiched between metallic electrodes. In this work, various scanning probe techniques are combined with numerical modeling to unravel their

  17. Design of convergent switched systems

    NARCIS (Netherlands)

    Berg, van den R.A.; Pogromsky, A.Y.; Leonov, G.A.; Rooda, J.E.; Pettersen, K.Y.; Gravdahl, J.T.; Nijmeijer, H.

    2006-01-01

    In this paper we deal with the problem of rendering hybrid/nonlinear systems into convergent closed-loop systems by means of a feedback law or switching rules. We illustrate our approach to this problem by means of two examples: the anti-windup design for a marginally stable system with input

  18. Incorrect predictions reduce switch costs.

    Science.gov (United States)

    Kleinsorge, Thomas; Scheil, Juliane

    2015-07-01

    In three experiments, we combined two sources of conflict within a modified task-switching procedure. The first source of conflict was the one inherent in any task switching situation, namely the conflict between a task set activated by the recent performance of another task and the task set needed to perform the actually relevant task. The second source of conflict was induced by requiring participants to guess aspects of the upcoming task (Exps. 1 & 2: task identity; Exp. 3: position of task precue). In case of an incorrect guess, a conflict accrues between the representation of the guessed task and the actually relevant task. In Experiments 1 and 2, incorrect guesses led to an overall increase of reaction times and error rates, but they reduced task switch costs compared to conditions in which participants predicted the correct task. In Experiment 3, incorrect guesses resulted in faster performance overall and to a selective decrease of reaction times in task switch trials when the cue-target interval was long. We interpret these findings in terms of an enhanced level of controlled processing induced by a combination of two sources of conflict converging upon the same target of cognitive control. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  20. Stability of Randomly Switched Diffusions

    DEFF Research Database (Denmark)

    Schiøler, Henrik; Leth, John-Josef; Gholami, Mehdi

    2012-01-01

    This paper provides a sufficient criterion for ε-moment stability (boundedness) and ergodicity for a class of systems comprising a finite set of diffusions among which switching is governed by a continuous time Markov chain. Stability/instability properties for each separate subsystem are assumed...

  1. Industry Switching in Developing Countries

    DEFF Research Database (Denmark)

    Newman, Carol; Rand, John; Tarp, Finn

    Firm turnover (i.e. firm entry and exit) is a well-recognized source of sectorlevel productivity growth across developing and developed countries. In contrast, the role and importance of firms switching activities from one sector to another is little understood. Firm switchers are likely...

  2. Charge transport through molecular switches

    International Nuclear Information System (INIS)

    Jan van der Molen, Sense; Liljeroth, Peter

    2010-01-01

    We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

  3. Charge transport through molecular switches

    Energy Technology Data Exchange (ETDEWEB)

    Jan van der Molen, Sense [Kamerlingh Onnes Laboratorium, Leiden University, Niels Bohrweg 2, 2333 CA Leiden (Netherlands); Liljeroth, Peter, E-mail: molen@physics.leidenuniv.n [Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, University of Utrecht, PO Box 80000, 3508 TA Utrecht (Netherlands)

    2010-04-07

    We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

  4. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-07-03

    Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

  5. The Atlas load protection switch

    CERN Document Server

    Davis, H A; Dorr, G; Martínez, M; Gribble, R F; Nielsen, K E; Pierce, D; Parsons, W M

    1999-01-01

    Atlas is a high-energy pulsed-power facility under development to study materials properties and hydrodynamics experiments under extreme conditions. Atlas will implode heavy liner loads (m~45 gm) with a peak current of 27-32 MA delivered in 4 mu s, and is energized by 96, 240 kV Marx generators storing a total of 23 MJ. A key design requirement for Atlas is obtaining useful data for 95601130f all loads installed on the machine. Materials response calculations show current from a prefire can damage the load requiring expensive and time consuming replacement. Therefore, we have incorporated a set of fast-acting mechanical switches in the Atlas design to reduce the probability of a prefire damaging the load. These switches, referred to as the load protection switches, short the load through a very low inductance path during system charge. Once the capacitors have reached full charge, the switches open on a time scale short compared to the bank charge time, allowing current to flow to the load when the trigger pu...

  6. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing

    2013-03-15

    Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

  7. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  8. High voltage MOSFET switching circuit

    Science.gov (United States)

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  9. FORMALIZATION OF LOCOMOTIVE DRIVER ACTIVITY TENSION INDICATOR BASED ON THE ERGONOMIC MODEL

    Directory of Open Access Journals (Sweden)

    O. M. Horobchenko

    2017-02-01

    Full Text Available Purpose. A key factor contributing to the safety and quality of ergatic system "train-driver" is the intensity of the locomotive crew’s work. The aim of this work is formalization of locomotive driver activity tension indicator. Methodology. One of the characteristics of driver activity tension is the difference between the time allotted to complete the task, and the necessary (external reserve or deficiency time. The sets of major and minor operations in the management of the train locomotive in different train situations were identified. Using the methods of fuzzy logic, the concept of "materiality of the operation of the locomotive control" is presented in the form of a set of linguistic variables. To determine the function membership of the elements of the set "the importance of the operation of the locomotive control" the method of expert evaluations was used. Coefficient of temporary tension is presented in the form of fuzzy number L-R-type. Findings. It was found the value of the relative number of operations of locomotive control according to the distribution using the parameter of operation "importance". To determine the most tensioned mode of the driver ranking the traffic condition according to the parameter of relative amounts of the important management operations was conducted. The most difficult modes are the "front hindrance", "movement in unfavorable weather conditions" and "departure from the station to the running line". Originality. The introduction of the value "conventional importance of the operation" allowed us to more accurately describe the terms of train driving. For the first time the work presents determination of tension of the driver’s work in the form of a unimodal fuzzy number, which will make it possible to use the methods of the theory of artificial intelligence to simulate activity of the locomotive driver and develop intelligent control systems. Practical value. There were obtained the opportunity to

  10. Switch-connected HyperX network

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip

    2018-02-13

    A network system includes a plurality of sub-network planes and global switches. The sub-network planes have a same network topology as each other. Each of the sub-network planes includes edge switches. Each of the edge switches has N ports. Each of the global switches is configured to connect a group of edge switches at a same location in the sub-network planes. In each of the sub-network planes, some of the N ports of each of the edge switches are connected to end nodes, and others of the N ports are connected to other edge switches in the same sub-network plane, other of the N ports are connected to at least one of the global switches.

  11. HoverBots: Precise Locomotion Using Robots That Are Designed for Manufacturability

    Directory of Open Access Journals (Sweden)

    Markus P. Nemitz

    2017-11-01

    Full Text Available Scaling up robot swarms to collectives of hundreds or even thousands without sacrificing sensing, processing, and locomotion capabilities is a challenging problem. Low-cost robots are potentially scalable, but the majority of existing systems have limited capabilities, and these limitations substantially constrain the type of experiments that could be performed by robotics researchers. As an alternative to increasing the quantity of robots by reducing their functionality, we have developed a new technology that delivers increased functionality at low-cost. In this study, we present a comprehensive literature review on the most commonly used locomotion strategies of swarm robotic systems. We introduce a new type of low-friction locomotion—active low-friction locomotion—and we show its first implementation in the HoverBot system. The HoverBot system consists of an air levitation and magnet table, and a HoverBot agent. HoverBot agents are levitating circuit boards that we have equipped with an array of planar coils and a Hall-effect sensor. The HoverBot agent uses its coils to pull itself toward magnetic anchors that are embedded into a levitation table. These robots use active low-friction locomotion; consist of only surface-mount components; circumvent actuator calibration; are capable of odometry by using a single Hall-effect sensor; and perform precise movement. We conducted three hours of experimental evaluation of the HoverBot system in which we observed the system performing more than 10,000 steps. We also demonstrate formation movement, random collision, and straight collisions with two robots. This study demonstrates that active low-friction locomotion is an alternative to wheeled and slip-stick locomotion in the field of swarm robotics.

  12. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons.

    Science.gov (United States)

    Long, Yi; Du, Zhi-Jiang; Wang, Wei-Dong; Zhao, Guang-Yu; Xu, Guo-Qiang; He, Long; Mao, Xi-Wang; Dong, Wei

    2016-09-02

    Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM) optimized by particle swarm optimization (PSO) to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS) attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz), a three-layer wavelet packet analysis (WPA) is used for feature extraction, after which, the kernel principal component analysis (kPCA) is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA) is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance.

  13. SIMULATION OF DRIVER’S LOCOMOTIVE-HANDLING ACTIVITY USING THE THEORY OF FUZZY GRAPHS

    Directory of Open Access Journals (Sweden)

    T. V. Butko

    2015-03-01

    Full Text Available Purpose. The efficiency and safety of locomotive control improving is important and relevant scientific and practical problem. Every driver during the trains-handling bases on his experience and knowledge, that is why the compilation and detection the most efficient ways to control the locomotive-handling is one of the stages of measures development to reduce transportation costs. The purpose of this paper is a formalization process description of locomotive-handling and quality parameters determination of this process. Methodology. In order to achieve this goal the theory of fuzzy probabilistic graphs was used. Vertices of the graph correspond to the events start and end operations at train-handling. The graph arcs describe operations on train-handling. Graph consists of thirteen peaks corresponding to the main control actions of the engine-driver. The weighting factors of transitions between vertices are assigned by fuzzy numbers. Their values were obtained by expert estimates. Fuzzy probabilities and transition time are presented as numbers with trapezoidal membership function. Findings. Using successive merging of parallel arcs, loops and vertices elimination, the equivalent fuzzy graph of train-handling and the corresponding L-matrix were obtained. Equivalent graph takes into account separately activity of the driver during normal operation and during emergency situations. Originality. The theoretical foundations of describing process formalization in driver’s locomotive-handling activity were developed using the fuzzy probabilistic graph. The parameters characterizing the decision-making process of engineer were obtained. Practical value. With the resulting model it is possible to estimate the available reserves for the quality improvement of locomotive-handling. Reduction in the time for decision-making will lead to the approximation the current mode of control to the rational one and decrease costs of hauling operations. And reduction

  14. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons

    Directory of Open Access Journals (Sweden)

    Yi Long

    2016-09-01

    Full Text Available Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM optimized by particle swarm optimization (PSO to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz, a three-layer wavelet packet analysis (WPA is used for feature extraction, after which, the kernel principal component analysis (kPCA is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance.

  15. Afferent control of central pattern generators: experimental analysis of locomotion in the decerebrate cat.

    Science.gov (United States)

    Baev, K V; Esipenko, V B; Shimansky YuP

    1991-01-01

    Changes in the motor activity of the spinal locomotor generator evoked by tonic and phasic peripheral afferent signals during fictitious locomotion of both slow and fast rhythms were analysed in the cat. The tonic afferent inflow was conditioned by the position of the hindlimb. The phasic afferent signals were imitated by electrical stimulation of hindlimb nerves. The correlation between the kinematics of hindlimb locomotor movement and sensory inflow was investigated during actual locomotion. Reliable correlations between motor activity parameters during fictitious locomotion were revealed in cases of both slow and fast "locomotor" rhythms. The main difference between these cases was that correlations "duration-intensity" were positive in the first and negative in the second case. The functional role of "locomotor" pattern dependence on tonic sensory inflow consisted of providing stability for planting the hindlimb on the ground. For any investigated afferent input the phase moments in the "locomotor" cycle were found, in which an afferent signal caused no rearrangement in locomotor generator activity. These moments corresponded to the transitions between "flexion" and "extension" phases and to the bursts of integral afferent activity observed during real locomotion. The data obtained are compared with the results previously described for the scratching generator. The character of changes in "locomotor" activity in response to tonic and phasic sensory signals was similar to that of such changes in "scratching" rhythm in the case of fast "locomotion". Intensification of the "flexion" phase caused by phasic high-intensity stimulation of cutaneous afferents during low "locomotor" rhythm was changed to inhibition (such as observed during "scratching") when this rhythm was fast. It is concluded that the main regularities of peripheral afferent control for both the locomotor and scratching generators are the same. Moreover, these central pattern generators are just

  16. Biomechanics of gecko locomotion: the patterns of reaction forces on inverted, vertical and horizontal substrates

    International Nuclear Information System (INIS)

    Wang, Zhouyi; Dai, Zhendong; Ji, Aihong; Xing, Qiang; Ren, Lei; Dai, Liming

    2015-01-01

    The excellent locomotion ability of geckos on various rough and/or inclined substrates has attracted scientists’ attention for centuries. However, the moving ability of gecko-mimicking robots on various inclined surfaces still lags far behind that of geckos, mainly because our understanding of how geckos govern their locomotion is still very poor. To reveal the fundamental mechanism of gecko locomotion and also to facilitate the design of gecko-mimicking robots, we have measured the reaction forces (RFs) acting on each individual foot of moving geckos on inverted, vertical and horizontal substrates (i.e. ceiling, wall and floor), have associated the RFs with locomotion behaviors by using high-speed camera, and have presented the relationships of the force components with patterns of reaction forces (PRFs). Geckos generate different PRF on ceiling, wall and floor, that is, the PRF is determined by the angles between the direction of gravity and the substrate on which geckos move. On the ceiling, geckos produce reversed shear forces acting on the front and hind feet, which pull away from the body in both lateral and fore-aft directions. They use a very large supporting angle from 21° to 24° to reduce the forces acting on their legs and feet. On the floor, geckos lift their bodies using a supporting angle from 76° to 78°, which not only decreases the RFs but also improves their locomotion ability. On the wall, geckos generate a reliable self-locking attachment by using a supporting angle of 14.8°, which is only about half of the critical angle of detachment. (paper)

  17. Isolated converter with synchronized switching leg

    NARCIS (Netherlands)

    2003-01-01

    An amplification device is disclosed providing a way of integrating a switch mode power supply and a class D amplifier (switch mode amplifier). This results in the usage of basically one magnetic component (1), one major energy storage element (4) and switches (20, 30) that are controlled in such a

  18. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

  19. A CW Gunn diode bistable switching element.

    Science.gov (United States)

    Hurtado, M.; Rosenbaum, F. J.

    1972-01-01

    Experiments with a current-controlled bistable switching element using a CW Gunn diode are reported. Switching rates of the order of 10 MHz have been obtained. Switching is initiated by current pulses of short duration (5-10 ns). Rise times of the order of several nanoseconds could be obtained.

  20. A gain-coefficient switched Alexandrite laser

    International Nuclear Information System (INIS)

    Lee, Chris J; Van der Slot, Peter J M; Boller, Klaus-J

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  1. 47 CFR 69.106 - Local switching.

    Science.gov (United States)

    2010-10-01

    ... foreign services that use local exchange switching facilities. (c) If end users of an interstate or... local exchange carriers shall establish rate elements for local switching as follows: (1) Price cap... use local exchange switching facilities for the provision of interstate or foreign services. The...

  2. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  3. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  4. Control and synchronisation in switched arrival systems

    NARCIS (Netherlands)

    Rem, B.; Armbruster, H.D.

    2003-01-01

    A chaotic model of a production flow called the switched arrival system is extended to include switching times and maintenance. The probability distribution of the chaotic return times is calculated. Scheduling maintenance, loss of production due to switching, and control of the chaotic dynamics is

  5. [Possible changes in energy-minimizer mechanisms of locomotion due to chronic low back pain - a literature review].

    Science.gov (United States)

    de Carvalho, Alberito Rodrigo; Andrade, Alexandro; Peyré-Tartaruga, Leonardo Alexandre

    2015-01-01

    One goal of the locomotion is to move the body in the space at the most economical way possible. However, little is known about the mechanical and energetic aspects of locomotion that are affected by low back pain. And in case of occurring some damage, little is known about how the mechanical and energetic characteristics of the locomotion are manifested in functional activities, especially with respect to the energy-minimizer mechanisms during locomotion. This study aimed: a) to describe the main energy-minimizer mechanisms of locomotion; b) to check if there are signs of damage on the mechanical and energetic characteristics of the locomotion due to chronic low back pain (CLBP) which may endanger the energy-minimizer mechanisms. This study is characterized as a narrative literature review. The main theory that explains the minimization of energy expenditure during the locomotion is the inverted pendulum mechanism, by which the energy-minimizer mechanism converts kinetic energy into potential energy of the center of mass and vice-versa during the step. This mechanism is strongly influenced by spatio-temporal gait (locomotion) parameters such as step length and preferred walking speed, which, in turn, may be severely altered in patients with chronic low back pain. However, much remains to be understood about the effects of chronic low back pain on the individual's ability to practice an economic locomotion, because functional impairment may compromise the mechanical and energetic characteristics of this type of gait, making it more costly. Thus, there are indications that such changes may compromise the functional energy-minimizer mechanisms. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

  6. Optimization of multi-branch switched diversity systems

    KAUST Repository

    Nam, Haewoon; Alouini, Mohamed-Slim

    2009-01-01

    A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold

  7. Electronic logic to enhance switch reliability in detecting openings and closures of redundant switches

    Science.gov (United States)

    Cooper, James A.

    1986-01-01

    A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and failsafe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

  8. Large aperture optical switching devices

    International Nuclear Information System (INIS)

    Goldhar, J.; Henesian, M.A.

    1983-01-01

    We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs

  9. Shape memory thermal conduction switch

    Science.gov (United States)

    Vaidyanathan, Rajan (Inventor); Krishnan, Vinu (Inventor); Notardonato, William U. (Inventor)

    2010-01-01

    A thermal conduction switch includes a thermally-conductive first member having a first thermal contacting structure for securing the first member as a stationary member to a thermally regulated body or a body requiring thermal regulation. A movable thermally-conductive second member has a second thermal contacting surface. A thermally conductive coupler is interposed between the first member and the second member for thermally coupling the first member to the second member. At least one control spring is coupled between the first member and the second member. The control spring includes a NiTiFe comprising shape memory (SM) material that provides a phase change temperature <273 K, a transformation range <40 K, and a hysteresis of <10 K. A bias spring is between the first member and the second member. At the phase change the switch provides a distance change (displacement) between first and second member by at least 1 mm, such as 2 to 4 mm.

  10. Negation switching invariant signed graphs

    Directory of Open Access Journals (Sweden)

    Deepa Sinha

    2014-04-01

    Full Text Available A signed graph (or, $sigraph$ in short is a graph G in which each edge x carries a value $\\sigma(x \\in \\{-, +\\}$ called its sign. Given a sigraph S, the negation $\\eta(S$ of the sigraph S is a sigraph obtained from S by reversing the sign of every edge of S. Two sigraphs $S_{1}$ and $S_{2}$ on the same underlying graph are switching equivalent if it is possible to assign signs `+' (`plus' or `-' (`minus' to vertices of $S_{1}$ such that by reversing the sign of each of its edges that has received opposite signs at its ends, one obtains $S_{2}$. In this paper, we characterize sigraphs which are negation switching invariant and also see for what sigraphs, S and $\\eta (S$ are signed isomorphic.

  11. Switch for Good Community Program

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Tabitha [Balfour Beatty Military Housing Management LLC, Newtown Square, PA (United States); Amran, Martha [WattzOn, Inc., Mountain View, CA (United States)

    2013-11-19

    Switch4Good is an energy-savings program that helps residents reduce consumption from behavior changes; it was co-developed by Balfour Beatty Military Housing Management (BB) and WattzOn in Phase I of this grant. The program was offered at 11 Navy bases. Three customer engagement strategies were evaluated, and it was found that Digital Nudges (a combination of monthly consumption statements with frequent messaging via text or email) was most cost-effective. The program was delivered on-time and on-budget, and its success is based on the teamwork of local BB staff and the WattzOn team. The following graphic shows Switch4Good “by the numbers”, e.g. the scale of operations achieved during Phase I.

  12. Pulsed laser triggered high speed microfluidic switch

    Science.gov (United States)

    Wu, Ting-Hsiang; Gao, Lanyu; Chen, Yue; Wei, Kenneth; Chiou, Pei-Yu

    2008-10-01

    We report a high-speed microfluidic switch capable of achieving a switching time of 10 μs. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic polydimethylsiloxane (PDMS) channel. The bubble expansion deforms the elastic PDMS channel wall and squeezes the adjacent sample channel to control its fluid and particle flows as captured by the time-resolved imaging system. A switching of polystyrene microspheres in a Y-shaped channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of state-of-the-art microscale fluorescence activated cell sorting devices.

  13. Secure videoconferencing equipment switching system and method

    Science.gov (United States)

    Hansen, Michael E [Livermore, CA

    2009-01-13

    A switching system and method are provided to facilitate use of videoconference facilities over a plurality of security levels. The system includes a switch coupled to a plurality of codecs and communication networks. Audio/Visual peripheral components are connected to the switch. The switch couples control and data signals between the Audio/Visual peripheral components and one but nor both of the plurality of codecs. The switch additionally couples communication networks of the appropriate security level to each of the codecs. In this manner, a videoconferencing facility is provided for use on both secure and non-secure networks.

  14. Switching strategies to optimize search

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2016-01-01

    Search strategies are explored when the search time is fixed, success is probabilistic and the estimate for success can diminish with time if there is not a successful result. Under the time constraint the problem is to find the optimal time to switch a search strategy or search location. Several variables are taken into account, including cost, gain, rate of success if a target is present and the probability that a target is present. (paper: interdisciplinary statistical mechanics)

  15. Correlated randomness and switching phenomena

    Science.gov (United States)

    Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Kumar, P.; Plerou, V.; Preis, T.

    2010-08-01

    One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines have no perfect metronome in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. Further, many of these processes and structures have the remarkable feature of “switching” from one behavior to another as if by magic. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many spatial and temporal patterns in biology, medicine, and economics and even begin to characterize the switching phenomena that enables a system to pass from one state to another. Inspired by principles developed by A. Nihat Berker and scores of other statistical physicists in recent years, we discuss some applications of correlated randomness to understand switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water’s anomalies are related to a switching point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not “outliers” (another Gladwell immortalization). Though more speculative, we support the idea of disease as arising from some kind of yet-to-be-understood complex switching phenomenon, by discussing data on selected examples, including heart disease and Alzheimer disease.

  16. The effects of ketamine on sexual behavior, anxiety, and locomotion in female rats.

    Science.gov (United States)

    Guarraci, Fay A; Gonzalez, Chantal M F; Lucero, Devon; Womble, Paige D; Abdel-Rahim, Heba; DeVore, Jennie; Kunkel, Marcela Nicole; Quadlander, Emma; Stinnett, Morgan; Boyette-Davis, Jessica

    2018-02-01

    The present study characterized the effects of ketamine on sexual behavior and anxiety in female rats. In Experiment 1, female subjects received an injection of ketamine (10.0mg/kg) or saline 30min prior to a sexual partner-preference test during which each female subject was given the opportunity to interact with a female stimulus or a sexually vigorous male stimulus. Immediately afterwards, female subjects were tested for locomotion in an open field test. Ketamine-treated subjects spent significantly more time with the male stimulus than saline-treated subjects. No other measures of mating behavior (i.e., paced mating behavior, lordosis) were affected by ketamine. Ketamine also had no effect on locomotion. In Experiment 2, female subjects received an injection of ketamine (10.0mg/kg), or saline daily for 10days to investigate the possibility that sexual dysfunction emerges only after repeated exposure. Similar to the results of Experiment 1, ketamine-treated subjects spent significantly more time with the male stimulus than saline-treated subjects. Chronic ketamine treatment also decreased the likelihood of leaving the male after mounts, without affecting any other measures of sexual behavior. Chronic ketamine had no effect on locomotion. In Experiment 3, female subjects received an injection of ketamine (10.0mg/kg) or saline and were tested for anxiety in an elevated plus maze test and for locomotion in an open field test. Acute ketamine had no effect on anxiety or locomotion. In Experiment 4, female subjects received an injection of ketamine (10.0mg/kg) or saline daily for 10days to investigate the possibility that anxiety emerges only after repeated exposure. Chronic ketamine exposure had no effect on any measure of anxiety. However, chronic ketamine exposure increased locomotion. The results from these experiments indicate that unlike other medications prescribed for depression, neither acute nor chronic ketamine treatment causes anxiety or disruption of

  17. Interactions between posture and locomotion: motor patterns in humans walking with bent posture versus erect posture.

    Science.gov (United States)

    Grasso, R; Zago, M; Lacquaniti, F

    2000-01-01

    Human erect locomotion is unique among living primates. Evolution selected specific biomechanical features that make human locomotion mechanically efficient. These features are matched by the motor patterns generated in the CNS. What happens when humans walk with bent postures? Are normal motor patterns of erect locomotion maintained or completely reorganized? Five healthy volunteers walked straight and forward at different speeds in three different postures (regular, knee-flexed, and knee- and trunk-flexed) while their motion, ground reaction forces, and electromyographic (EMG) activity were recorded. The three postures imply large differences in the position of the center of body mass relative to the body segments. The elevation angles of the trunk, pelvis, and lower limb segments relative to the vertical in the sagittal plane, the ground reaction forces and the rectified EMGs were analyzed over the gait cycle. The waveforms of the elevation angles along the gait cycle remained essentially unchanged irrespective of the adopted postures. The first two harmonics of these kinematic waveforms explain >95% of their variance. The phase shift but not the amplitude ratio between the first harmonic of the elevation angle waveforms of adjacent pairs was affected systematically by changes in posture. Thigh, shank, and foot angles covaried close to a plane in all conditions, but the plane orientation was systematically different in bent versus erect locomotion. This was explained by the changes in the temporal coupling among the three segments. For walking speeds >1 m s(-1), the plane orientation of bent locomotion indicates a much lower mechanical efficiency relative to erect locomotion. Ground reaction forces differed prominently in bent versus erect posture displaying characteristics intermediate between those typical of walking and those of running. Mean EMG activity was greater in bent postures for all recorded muscles independent of the functional role. The waveforms

  18. Fast superconducting magnetic field switch

    Science.gov (United States)

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  19. Fast superconducting magnetic field switch

    International Nuclear Information System (INIS)

    Goren, Y.; Mahale, N.K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs

  20. Coating possibilities for magnetic switches

    International Nuclear Information System (INIS)

    Sharp, D.J.; Harjes, H.C.; Mann, G.A.; Morgan, F.A.

    1990-01-01

    High average power magnetic pulse compression systems are now being considered for use in several applications such as the High Power Radiation Source (HiPoRS) project. Such systems will require high reliability magnetic switches (saturable inductors) that are very efficient and have long lifetimes. One of the weakest components in magnetic switches is their interlaminar insulation. Considerations related to dielectric breakdown, thermal management of compact designs, and economical approaches for achieving these needs must be addressed. Various dielectric insulation and coating materials have been applied to Metglas foil in an attempt to solve the complex technical and practical problems associated with large magnetic switch structures. This work reports various needs, studies, results, and proposals in selecting and evaluating continuous coating approaches for magnetic foil. Techniques such as electrophoretic polymer deposition and surface chemical oxidation are discussed. We also propose continuous photofabrication processes for applying dielectric ribs or spacers to the foil which permit circulation of dielectric liquids for cooling during repetitive operation. 10 refs., 8 figs., 11 tabs

  1. Analytical Performance Evaluation of Different Switch Solutions

    Directory of Open Access Journals (Sweden)

    Francisco Sans

    2013-01-01

    Full Text Available The virtualization of the network access layer has opened new doors in how we perceive networks. With this virtualization of the network, it is possible to transform a regular PC with several network interface cards into a switch. PC-based switches are becoming an alternative to off-the-shelf switches, since they are cheaper. For this reason, it is important to evaluate the performance of PC-based switches. In this paper, we present a performance evaluation of two PC-based switches, using Open vSwitch and LiSA, and compare their performance with an off-the-shelf Cisco switch. The RTT, throughput, and fairness for UDP are measured for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that the Cisco switch presents the best performance, and both PC-based switches have similar performance. Between Open vSwitch and LiSA, Open vSwitch represents a better choice since it has more features and is currently actively developed.

  2. Streamer model for high voltage water switches

    International Nuclear Information System (INIS)

    Sazama, F.J.; Kenyon, V.L. III

    1979-01-01

    An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented

  3. Optical Multidimensional Switching for Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija

    2017-01-01

    . Software controlled switching using an on-chip integrated fiber switch is demonstrated and enabling of additional network functionalities such as multicast and optical grooming is experimentally confirmed. Altogether this work demonstrates the potential of optical switching technologies...... for the purpose of deploying optical switching within the network. First, the Hi-Ring data center architecture is proposed. It is based on optical multidimensional switching nodes that provide switching in hierarchically layered space, wavelength and time domain. The performance of the Hi-Ring architecture...... is evaluated experimentally and successful switching of both high capacity wavelength connections and time-shared subwavelengthconnections is demonstrated. Error-free performance is also achieved when transmitting 7 Tbit/s using multicore fiber, confirming the ability to scale the network. Moreover...

  4. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  5. Synchronization in complex networks with switching topology

    International Nuclear Information System (INIS)

    Wang, Lei; Wang, Qing-guo

    2011-01-01

    This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. -- Highlights: → Synchronization of complex networks with switching topology is investigated. → A common Lyapunov function is established for synchronization of switching network. → The common Lyapunov function is not necessary to monotonically decrease with time. → Synchronization is determined by the second smallest eigenvalue of its Laplacian. → Synchronization criterion can be used to investigate various switching cases.

  6. Energy storage, compression, and switching. Vol. 2

    International Nuclear Information System (INIS)

    Nardi, V.; Bostick, W.H.; Sahlin, H.

    1983-01-01

    This book is a compilation of papers presented at the Second International Conference on Energy Storage, Compression, and Switching, which was held in order to assemble active researchers with a major interest in plasma physics, electron beams, electric and magnetic energy storage systems, high voltage and high current switches, free-electron lasers, and pellet implosion plasma focus. Topics covered include: Slow systems: 50-60 Hz machinery, homopolar generators, slow capacitors, inductors, and solid state switches; Intermediate systems: fast capacitor banks; superconducting storage and switching; gas, vacuum, and dielectric switching; nonlinear (magnetic) switching; imploding liners capacitors; explosive generators; and fuses; and Fast systems: Marx, Blumlein, oil, water, and pressurized water dielectrics; switches; magnetic insulation; electron beams; and plasmas

  7. Locomotion Dynamics for Bio-inspired Robots with Soft Appendages: Application to Flapping Flight and Passive Swimming

    Science.gov (United States)

    Boyer, Frédéric; Porez, Mathieu; Morsli, Ferhat; Morel, Yannick

    2017-08-01

    In animal locomotion, either in fish or flying insects, the use of flexible terminal organs or appendages greatly improves the performance of locomotion (thrust and lift). In this article, we propose a general unified framework for modeling and simulating the (bio-inspired) locomotion of robots using soft organs. The proposed approach is based on the model of Mobile Multibody Systems (MMS). The distributed flexibilities are modeled according to two major approaches: the Floating Frame Approach (FFA) and the Geometrically Exact Approach (GEA). Encompassing these two approaches in the Newton-Euler modeling formalism of robotics, this article proposes a unique modeling framework suited to the fast numerical integration of the dynamics of a MMS in both the FFA and the GEA. This general framework is applied on two illustrative examples drawn from bio-inspired locomotion: the passive swimming in von Karman Vortex Street, and the hovering flight with flexible flapping wings.

  8. COMPARATIVE ANALYSIS OF CONVERTER STRUCTURES OF THE TRACTION DRIVE PROSPECTIVE MULTI-SYSTEM ELECTRIC LOCOMOTIVES WITH DC TRACTION MOTORS

    Directory of Open Access Journals (Sweden)

    A. M. Muha

    2009-03-01

    Full Text Available In the article the structured schemes of steady-state converter are offered for traction drive of promising multisystem electric locomotives with traction engines of direct current and their comparative analysis is conducted.

  9. A remotely-controlled locomotive IC driven by electrolytic bubbles and wireless powering.

    Science.gov (United States)

    Hsieh, Jian-Yu; Kuo, Po-Hung; Huang, Yi-Chun; Huang, Yu-Jie; Tsai, Rong-Da; Wang, Tao; Chiu, Hung-Wei; Wang, Yao-Hung; Lu, Shey-Shi

    2014-12-01

    A batteryless remotely-controlled locomotive IC utilizing electrolytic bubbles as propelling force is realized in 0.35 μm CMOS technology. Without any external components, such as magnets and on-board coils, the bare IC is wirelessly powered and controlled by a 10 MHz ASK modulated signal with RS232 control commands to execute movement in four moving directions and with two speeds. The receiving coil and electrolysis electrodes are all integrated on the locomotive chip. The experiment successfully demonstrated that the bare IC moved on the surface of an electrolyte with a speed up to 0.3 mm/s and change moving directions according to the commands. The total power consumptions of the chip are 207.4 μW and 180 μ W while the output electrolysis voltages are 2 V and 1.3 V, respectively.

  10. Efficient worm-like locomotion: slip and control of soft-bodied peristaltic robots

    International Nuclear Information System (INIS)

    Daltorio, Kathryn A; Horchler, Andrew D; Quinn, Roger D; Boxerbaum, Alexander S; Shaw, Kendrick M; Chiel, Hillel J

    2013-01-01

    In this work, we present a dynamic simulation of an earthworm-like robot moving in a pipe with radially symmetric Coulomb friction contact. Under these conditions, peristaltic locomotion is efficient if slip is minimized. We characterize ways to reduce slip-related losses in a constant-radius pipe. Using these principles, we can design controllers that can navigate pipes even with a narrowing in radius. We propose a stable heteroclinic channel controller that takes advantage of contact force feedback on each segment. In an example narrowing pipe, this controller loses 40% less energy to slip compared to the best-fit sine wave controller. The peristaltic locomotion with feedback also has greater speed and more consistent forward progress. (paper)

  11. Life-Cycle Assessment of the Use of Jatropha Biodiesel in Indian Locomotives (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, M.; Heath, G.

    2009-03-01

    With India's transportation sector relying heavily on imported petroleum-based fuels, the Planning Commission of India and the Indian government recommended the increased use of blended biodiesel in transportation fleets, identifying Jatropha as a potentially important biomass feedstock. The Indian Oil Corporation and Indian Railways are collaborating to increase the use of biodiesel blends in Indian locomotives with blends of up to B20, aiming to reduce GHG emissions and decrease petroleum consumption. To help evaluate the potential for Jatropha-based biodiesel in achieving sustainability and energy security goals, this study examines the life cycle, net GHG emission, net energy ratio, and petroleum displacement impacts of integrating Jatropha-based biodiesel into locomotive operations in India. In addition, this study identifies the parameters that have the greatest impact on the sustainability of the system.

  12. Distributed Recurrent Neural Forward Models with Neural Control for Complex Locomotion in Walking Robots

    DEFF Research Database (Denmark)

    Dasgupta, Sakyasingha; Goldschmidt, Dennis; Wörgötter, Florentin

    2015-01-01

    here, an artificial bio-inspired walking system which effectively combines biomechanics (in terms of the body and leg structures) with the underlying neural mechanisms. The neural mechanisms consist of (1) central pattern generator based control for generating basic rhythmic patterns and coordinated......Walking animals, like stick insects, cockroaches or ants, demonstrate a fascinating range of locomotive abilities and complex behaviors. The locomotive behaviors can consist of a variety of walking patterns along with adaptation that allow the animals to deal with changes in environmental...... conditions, like uneven terrains, gaps, obstacles etc. Biological study has revealed that such complex behaviors are a result of a combination of biomechanics and neural mechanism thus representing the true nature of embodied interactions. While the biomechanics helps maintain flexibility and sustain...

  13. Design of a biped locomotion controller based on adaptive neuro-fuzzy inference systems

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, M-Y; Chang, K-H [Department of E. E., Southern Taiwan University, 1 Nantai St., YungKang City, Tainan County 71005, Taiwan (China); Lia, Y-S [Executive Director Office, ITRI, Southern Taiwan Innovation Park, Tainan County, Taiwan (China)], E-mail: myshieh@mail.stut.edu.tw

    2008-02-15

    This paper proposes a method for the design of a biped locomotion controller based on the ANFIS (Adaptive Neuro-Fuzzy Inference System) inverse learning model. In the model developed here, an integrated ANFIS structure is trained to function as the system identifier for the modeling of the inverse dynamics of a biped robot. The parameters resulting from the modeling process are duplicated and integrated as those of the biped locomotion controller to provide favorable control action. As the simulation results show, the proposed controller is able to generate a stable walking cycle for a biped robot. Moreover, the experimental results demonstrate that the performance of the proposed controller is satisfactory under conditions when the robot stands in different postures or moves on a rugged surface.

  14. Design of a biped locomotion controller based on adaptive neuro-fuzzy inference systems

    International Nuclear Information System (INIS)

    Shieh, M-Y; Chang, K-H; Lia, Y-S

    2008-01-01

    This paper proposes a method for the design of a biped locomotion controller based on the ANFIS (Adaptive Neuro-Fuzzy Inference System) inverse learning model. In the model developed here, an integrated ANFIS structure is trained to function as the system identifier for the modeling of the inverse dynamics of a biped robot. The parameters resulting from the modeling process are duplicated and integrated as those of the biped locomotion controller to provide favorable control action. As the simulation results show, the proposed controller is able to generate a stable walking cycle for a biped robot. Moreover, the experimental results demonstrate that the performance of the proposed controller is satisfactory under conditions when the robot stands in different postures or moves on a rugged surface

  15. BiLBIQ A Biologically Inspired Robot with Walking and Rolling Locomotion

    CERN Document Server

    King, Ralf Simon

    2013-01-01

    The book ‘BiLBIQ: A biologically inspired Robot with walking and rolling locomotion’ deals with implementing a locomotion behavior observed in the biological archetype Cebrennus villosus to a robot prototype whose structural design needs to be developed.   The biological sample is investigated as far as possible and compared to other evolutional solutions within the framework of nature’s inventions. Current achievements in robotics are examined and evaluated for their relation and relevance to the robot prototype in question. An overview of what is state of the art in actuation ensures the choice of the hardware available and most suitable for this project. Through a constant consideration of the achievement of two fundamentally different ways of locomotion with one and the same structure, a robot design is developed and constructed taking hardware constraints into account. The development of a special leg structure that needs to resemble and replace body elements of the biological archetype is a speci...

  16. Posture and Locomotion Coupling: A Target for Rehabilitation Interventions in Persons with Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Marie-Laure Mille

    2012-01-01

    Full Text Available Disorders of posture, balance, and gait are debilitating motor manifestations of advancing Parkinson's disease requiring rehabilitation intervention. These problems often reflect difficulties with coupling or sequencing posture and locomotion during complex whole body movements linked with falls. Considerable progress has been made with demonstrating the effectiveness of exercise interventions for individuals with Parkinson's disease. However, gaps remain in the evidence base for specific interventions and the optimal content of exercise interventions. Using a conceptual theoretical framework and experimental findings, this perspective and review advances the viewpoint that rehabilitation interventions focused on separate or isolated components of posture, balance, or gait may limit the effectiveness of current clinical practices. It is argued that treatment effectiveness may be improved by directly targeting posture and locomotion coupling problems as causal factors contributing to balance and gait dysfunction. This approach may help advance current clinical practice and improve outcomes in rehabilitation for persons with Parkinson's disease.

  17. The coordination between mechanical and chemical subsystems initiates locomotion of Physarum plasmodial fragments

    Science.gov (United States)

    Zhang, Shun; Guy, Robert; Del Alamo, Juan Carlos

    2017-11-01

    Physarum polycephalum is a multinucleated slime mold whose endoplasm flows periodically driven by the contraction of its ectoplasm, a dense shell of F-actin cross-linked by myosin molecular motors and attached to the cell membrane. We find that physarum fragments smaller than 100 microns remain round and stay in place. However, larger fragments break symmetry leading to sustained forward locomotion, in process that is reminiscent of an interfacial instability that seems to settle around two different limit cycles (traveling waves and standing waves). We use both theory and experiments to study how coordination emerges between the different mechanical and chemical subsystems of the fragment to initiate locomotion. The role of many involved factors, such as fragment size, substratum adhesiveness, rheological properties, actin polymerization and traction stresses are investigated, and we find they agree well with our predictive model.

  18. Millipede-inspired locomotion through novel U-shaped piezoelectric motors

    International Nuclear Information System (INIS)

    Avirovik, Dragan; Butenhoff, Bryan; Priya, Shashank

    2014-01-01

    We report a novel piezoelectric motor that operates at a resonance frequency of 144 Hz, much lower than that of conventional ultrasonic motors, and meets the displacement and gait requirements for designing the locomotion mechanism of a millipede-inspired robot (millibot). The motor structure consists of two piezoelectric bimorphs arranged in a U-shaped configuration. Using the first bending mode for both the piezoelectric bimorphs an elliptical motion was obtained at the tip which led to the successful implementation of millipede inspired locomotion. At an input voltage of 70.7 V rms , the piezoelectric motor operating at resonance frequency was able to generate torque of 0.03 mN m, mechanical power of 0.84 mW and maximum velocity of 62 rad s −1 . Detailed discussion is provided about the principle of operation of the millibot. (technical note)

  19. To solve the specific emissions of locomotive diesel engines. Final report

    International Nuclear Information System (INIS)

    Korhonen, R.; Maeaettaenen, M.

    1999-01-01

    Ministry of Transport has made a goal to create an uniform system to make it possible to compare emissions of different transport forms. Kymenlaakso Polytechnic was supported by the Mobile Research Programme to measure the specific emissions of locomotive diesel engines. VR Osakeyhtioe has also supported economically the research work. During the research specific emissions of three diesel engines used in locomotives and calculated according to ISO 8178 standard were measured. In all, emissions of 14 engines were measured. For 12 engines measurements were made after the engine shop repair and for two engines before the repairing. Gaseous emissions: nitric oxide, carbon monoxide, carbon dioxide and total hydrocarbons contents were measured. Based on measured emissions and sulphur contents of the oil the weighted emissions were calculated in units g/kWh and g/kg fuel . Particular emissions were measured with dilution method and specific emissions were calculated in same units as for gaseous emissions

  20. Autonomous undulatory serpentine locomotion utilizing body dynamics of a fluidic soft robot

    International Nuclear Information System (INIS)

    Onal, Cagdas D; Rus, Daniela

    2013-01-01

    Soft robotics offers the unique promise of creating inherently safe and adaptive systems. These systems bring man-made machines closer to the natural capabilities of biological systems. An important requirement to enable self-contained soft mobile robots is an on-board power source. In this paper, we present an approach to create a bio-inspired soft robotic snake that can undulate in a similar way to its biological counterpart using pressure for actuation power, without human intervention. With this approach, we develop an autonomous soft snake robot with on-board actuation, power, computation and control capabilities. The robot consists of four bidirectional fluidic elastomer actuators in series to create a traveling curvature wave from head to tail along its body. Passive wheels between segments generate the necessary frictional anisotropy for forward locomotion. It takes 14 h to build the soft robotic snake, which can attain an average locomotion speed of 19 mm s −1 . (paper)

  1. A Novel Interactive Exoskeletal Robot for Overground Locomotion Studies in Rats.

    Science.gov (United States)

    Song, Yun Seong; Hogan, Neville

    2015-07-01

    This paper introduces a newly developed apparatus, Iron Rat, for locomotion research in rodents. Its main purpose is to allow maximal freedom of voluntary overground movement of the animal while providing forceful interaction to the hindlimbs. Advantages and challenges of the proposed exoskeletal apparatus over other existing designs are discussed. Design and implementation challenges are presented and discussed, emphasizing their implications for free, voluntary movement of the animal. A live-animal experiment was conducted to assess the design. Unconstrained natural movement of the animal was compared with its movement with the exoskeletal module attached. The compact design and back-drivable implementation of this apparatus will allow novel experimental manipulations that may include forceful yet compliant dynamic interaction with the animal's overground locomotion.

  2. Establishing the Range of Perceptually Natural Visual Walking Speeds for Virtual Walking-In-Place Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

    2014-01-01

    to virtual motion. This paper describes two within-subjects studies performed with the intention of establishing the range of perceptually natural walking speeds for WIP locomotion. In both studies, subjects performed a series of virtual walks while exposed to visual gains (optic flow multipliers) ranging...... from 1.0 to 3.0. Thus, the slowest speed was equal to an estimate of the subjects normal walking speed, while the highest speed was three times greater. The perceived naturalness of the visual speed was assessed using self-reports. The first study compared four different types of movement, namely...... proportional to the degree of underestimation of the virtual speeds for both treadmill-mediated virtual walking and WIP locomotion. Combined, the results constitute a first attempt at establishing a set of guidelines specifying what virtual walking speeds WIP gestures should produce in order to facilitate...

  3. Rolling towards a cleaner future: the development of Canadian locomotive emissions regulations

    International Nuclear Information System (INIS)

    2010-12-01

    In 2006, the Government of Canada published a notice of intent that it would develop regulations aimed at reducing anthropogenic criteria air contaminants and greenhouse gas emissions. The Government now intends to develop railway emissions regulations for criteria air contaminants under the Railway Safety Act. The Railway Safety Act not only provides the legislative basis for developing regulations governing railways, it also gives the authority for developing the rules governing federally regulated railroads to the Minister of Transport. For the future, Transport Canada will be responsible for developing regulations governing the rail sector. The transportation sector is a substantial emitter of criteria air contaminants, so rail transportation is a key element of the current work. This paper seeks to give a framework for consultations with stakeholders and facilitate dialogue. It collects feedback from stakeholders on the design of a Canadian regulatory regime for locomotive-generated criteria air contaminant emissions. Canadian railways have managed locomotive air contaminant emissions since 1995.

  4. Material Compressing Test of the High Polymer Part Used in Draft Gear of Heavy Load Locomotive

    Directory of Open Access Journals (Sweden)

    Wei Yangang

    2016-01-01

    Full Text Available According to the actual load cases of heavy load locomotive, the material compressing tests of the high polymer parts used in the locomotive are researched. The relationship between stress and strain during the material compressing are acquired by means of comparing the many results of the material compressing tests under different test condition. The relationship between stress and strain during the material compressing is nonlinear in large range of strain, but the relationship is approximately linear in small range of strain. The material of the high polymer made in China and the material of the high polymer imported are compared through the tests. The results show that the compressing property of the material of the high polymer made in China and the material of the high polymer imported are almost same. The research offers the foundation to study the structure elasticity of the draft gear.

  5. An evaluation of the use of mobile source emissions trading: Locomotive case study

    International Nuclear Information System (INIS)

    West, W.R.; Brazell, M.M.

    1993-01-01

    There are many proposals for generating mobil source credits for use by stationary and other sources. This paper examines the benefits and practicality of including locomotive rail emissions in proposed emissions trading programs in california. In particular, this paper examines (1) if trading of locomotive rail emissions will result in lower compliance costs for railroads than traditional open-quotes command and controlclose quotes approaches, and (2) if emissions trading programs provide large enough incentives to entice railroads to seek to meet or exceed expected emissions reduction open-quotes command and controlclose quotes targets. The paper also examines under what circumstances stationary sources would be willing to purchase mobile source credits from railroads, in order to offset some of the stationary source's emissions reductions requirements. Stated simply, this analysis examines whether proposed trading programs offer enough benefits to both trading partners to warrant their use

  6. Efficient worm-like locomotion: slip and control of soft-bodied peristaltic robots.

    Science.gov (United States)

    Daltorio, Kathryn A; Boxerbaum, Alexander S; Horchler, Andrew D; Shaw, Kendrick M; Chiel, Hillel J; Quinn, Roger D

    2013-09-01

    In this work, we present a dynamic simulation of an earthworm-like robot moving in a pipe with radially symmetric Coulomb friction contact. Under these conditions, peristaltic locomotion is efficient if slip is minimized. We characterize ways to reduce slip-related losses in a constant-radius pipe. Using these principles, we can design controllers that can navigate pipes even with a narrowing in radius. We propose a stable heteroclinic channel controller that takes advantage of contact force feedback on each segment. In an example narrowing pipe, this controller loses 40% less energy to slip compared to the best-fit sine wave controller. The peristaltic locomotion with feedback also has greater speed and more consistent forward progress

  7. The application of high-speed cinematography for the quantitative analysis of equine locomotion.

    Science.gov (United States)

    Fredricson, I; Drevemo, S; Dalin, G; Hjertën, G; Björne, K

    1980-04-01

    Locomotive disorders constitute a serious problem in horse racing which will only be rectified by a better understanding of the causative factors associated with disturbances of gait. This study describes a system for the quantitative analysis of the locomotion of horses at speed. The method is based on high-speed cinematography with a semi-automatic system of analysis of the films. The recordings are made with a 16 mm high-speed camera run at 500 frames per second (fps) and the films are analysed by special film-reading equipment and a mini-computer. The time and linear gait variables are presented in tabular form and the angles and trajectories of the joints and body segments are presented graphically.

  8. Cortex-dependent recovery of unassisted hindlimb locomotion after complete spinal cord injury in adult rats

    Science.gov (United States)

    Manohar, Anitha; Foffani, Guglielmo; Ganzer, Patrick D; Bethea, John R; Moxon, Karen A

    2017-01-01

    After paralyzing spinal cord injury the adult nervous system has little ability to ‘heal’ spinal connections, and it is assumed to be unable to develop extra-spinal recovery strategies to bypass the lesion. We challenge this assumption, showing that completely spinalized adult rats can recover unassisted hindlimb weight support and locomotion without explicit spinal transmission of motor commands through the lesion. This is achieved with combinations of pharmacological and physical therapies that maximize cortical reorganization, inducing an expansion of trunk motor cortex and forepaw sensory cortex into the deafferented hindlimb cortex, associated with sprouting of corticospinal axons. Lesioning the reorganized cortex reverses the recovery. Adult rats can thus develop a novel cortical sensorimotor circuit that bypasses the lesion, probably through biomechanical coupling, to partly recover unassisted hindlimb locomotion after complete spinal cord injury. DOI: http://dx.doi.org/10.7554/eLife.23532.001 PMID:28661400

  9. When Is Visual Information Used to Control Locomotion When Descending a Kerb?

    OpenAIRE

    Buckley, John G.; Timmis, Matthew A.; Scally, Andy J.; Elliott, David B.

    2011-01-01

    BACKGROUND: Descending kerbs during locomotion involves the regulation of appropriate foot placement before the kerb-edge and foot clearance over it. It also involves the modulation of gait output to ensure the body-mass is safely and smoothly lowered to the new level. Previous research has shown that vision is used in such adaptive gait tasks for feedforward planning, with vision from the lower visual field (lvf) used for online updating. The present study determined when lvf information is ...

  10. Vestibular-Somatosensory Convergence in Head Movement Control During Locomotion after Long-Duration Space Flight

    Science.gov (United States)

    Mulavara, Ajitkumar; Ruttley, Tara; Cohen, Helen; Peters, Brian; Miller, Chris; Brady, Rachel; Merkle, Lauren; Bloomberg, Jacob

    2010-01-01

    Exposure to the microgravity conditions of space flight induces adaptive modification in the control of vestibular-mediated reflexive head movement during locomotion after space flight. Space flight causes astronauts to be exposed to somatosensory adaptation in both the vestibular and body load-sensing (BLS) systems. The goal of these studies was to examine the contributions of vestibular and BLS-mediated somatosensory influences on head movement control during locomotion after long-duration space flight. Subjects were asked to walk on a treadmill driven at 1.8 m/s while performing a visual acuity task. Data were collected using the same testing protocol from three independent subject groups; 1) normal subjects before and after exposure to 30 minutes of 40% bodyweight unloaded treadmill walking, 2) bilateral labyrinthine deficient (LD) patients and 3) astronauts who performed the protocol before and after long duration space flight. Motion data from head and trunk segmental motion data were obtained to calculate the angular head pitch (HP) movements during walking trials while subjects performed the visual task, to estimate the contributions of vestibular reflexive mechanisms in HP movements. Results showed that exposure to unloaded locomotion caused a significant increase in HP movements, whereas in the LD patients the HP movements were significantly decreased. Astronaut subjects results showed a heterogeneous response of both increases and decreases in the amplitude of HP movement. We infer that BLS-mediated somatosensory input centrally modulates vestibular input and can adaptively modify head-movement control during locomotion. Thus, space flight may cause a central adaptation mediated by the converging vestibular and body load-sensing somatosensory systems.

  11. Development and Testing of a Mobile Robot with Hybrid Legged-Wheeled Locomotion

    Directory of Open Access Journals (Sweden)

    Petre Barbu

    2017-06-01

    Full Text Available In this paper the authors present the development and testing process of a mobile robot with hybrid legged-wheeled locomotion, that can be used for exploring dangerous environments. The robot has a high adaptability to rough terrain by being able to modify its ride height, to overpass step or ditch type obstacles and most of all, being able to operate while overturned or to revert itself into the normal operating position.

  12. Differential effects of absent visual feedback control on gait variability during different locomotion speeds.

    Science.gov (United States)

    Wuehr, M; Schniepp, R; Pradhan, C; Ilmberger, J; Strupp, M; Brandt, T; Jahn, K

    2013-01-01

    Healthy persons exhibit relatively small temporal and spatial gait variability when walking unimpeded. In contrast, patients with a sensory deficit (e.g., polyneuropathy) show an increased gait variability that depends on speed and is associated with an increased fall risk. The purpose of this study was to investigate the role of vision in gait stabilization by determining the effects of withdrawing visual information (eyes closed) on gait variability at different locomotion speeds. Ten healthy subjects (32.2 ± 7.9 years, 5 women) walked on a treadmill for 5-min periods at their preferred walking speed and at 20, 40, 70, and 80 % of maximal walking speed during the conditions of walking with eyes open (EO) and with eyes closed (EC). The coefficient of variation (CV) and fractal dimension (α) of the fluctuations in stride time, stride length, and base width were computed and analyzed. Withdrawing visual information increased the base width CV for all walking velocities (p < 0.001). The effects of absent visual information on CV and α of stride time and stride length were most pronounced during slow locomotion (p < 0.001) and declined during fast walking speeds. The results indicate that visual feedback control is used to stabilize the medio-lateral (i.e., base width) gait parameters at all speed sections. In contrast, sensory feedback control in the fore-aft direction (i.e., stride time and stride length) depends on speed. Sensory feedback contributes most to fore-aft gait stabilization during slow locomotion, whereas passive biomechanical mechanisms and an automated central pattern generation appear to control fast locomotion.

  13. Optimisation of a machine learning algorithm in human locomotion using principal component and discriminant function analyses

    OpenAIRE

    Bisele, M; Bencsik, M; Lewis, MGC; Barnett, CT

    2017-01-01

    Assessment methods in human locomotion often involve the description of normalised graphical profiles and/or the extraction of discrete variables. Whilst useful, these approaches may not represent the full complexity of gait data. Multivariate statistical methods, such as Principal Component Analysis (PCA) and Discriminant Function Analysis (DFA), have been adopted since they have the potential to overcome these data handling issues. The aim of the current study was to develop and optimise a ...

  14. Design of master control unit for laboratory prototype of traction converter for locomotives

    OpenAIRE

    Žák, Jan; Peroutka, Zdeněk; Ovaska, Seppo J.

    2008-01-01

    This paper deals with the prototype of a main traction converter with medium-frequency transformer for AC trolley wire-fed locomotives. The attention is paid to the new master control and diagnostic unit. The designed master control unit has been implemented in the LabVIEW environment. Our master control unit ensures an effective human interface between a user and the control hardware. In this case, the master unit makes possible both extensive control and diagnostic operations of the laborat...

  15. Trading of locomotive NO(sub x) emissions : a potential success story

    International Nuclear Information System (INIS)

    Gaines, L. L.; Biess, L. J.; Diedrich, G. K.

    2002-01-01

    New US Environmental Protection Agency regulations are forcing locomotive manufacturers and railroads to reduce pollutant emissions from locomotive operation. All new locomotives must meet strict standards when they are built, and existing locomotives must comply when they are rebuilt. Emissions can be reduced either by adjusting combustion parameters, which incurs a fuel penalty, or by turning the diesel engine off when the train is not moving and would otherwise be idling. The latter reduces fuel consumption, but requires installation of a device-such as an auxiliary power unit (APU)-to ensure that the engine can be restarted in cold weather and to supply hotel loads for the crew. Without a financial incentive, capital-short railroads will opt to achieve compliance in the least costly way. However, if they have the option of selling emissions credits from reducing emissions below regulated levels, it would be in their best interest to install additional equipment to minimize emissions. These credits could be purchased by businesses with compliance costs greater than either the cost of the credits or the fines they would have had to pay for non-compliance. The result is a financial benefit for both parties, and a net reduction in emissions, because the seller is emitting below regulated levels, and the buyer is no longer non-compliant. This paper describes a railroad as the potential seller, unable to consummate trades because of uncertainty in the regulatory environment, and estimates financial benefits and reductions in emissions and energy use that could be achieved if the barrier could be removed

  16. Ergonomics of locomotive design in South African Gold and Platinum mines.

    CSIR Research Space (South Africa)

    Smith, JR

    2002-03-01

    Full Text Available to determine reach, posture, field of view and control locations for the operator. • determining the design modifications, which would improve the overall operation of the mine locomotives in South African gold and platinum mines • formu... Acknowledgements Invaluable contributions from the following people are acknowledged: Mr J Annandale Impala Platinum Ltd., Shaft No. 1 Mr W Birmingham Joel Gold Mining Company Ltd. Mr W Brits Anglogold Ltd., Savuka Mine Mr G Burger Anglogold Ltd, West Wits...

  17. Enhancement of resistive switching properties in Al2O3 bilayer-based atomic switches: multilevel resistive switching

    Science.gov (United States)

    Vishwanath, Sujaya Kumar; Woo, Hyunsuk; Jeon, Sanghun

    2018-06-01

    Atomic switches are considered to be building blocks for future non-volatile data storage and internet of things. However, obtaining device structures capable of ultrahigh density data storage, high endurance, and long data retention, and more importantly, understanding the switching mechanisms are still a challenge for atomic switches. Here, we achieved improved resistive switching performance in a bilayer structure containing aluminum oxide, with an oxygen-deficient oxide as the top switching layer and stoichiometric oxide as the bottom switching layer, using atomic layer deposition. This bilayer device showed a high on/off ratio (105) with better endurance (∼2000 cycles) and longer data retention (104 s) than single-oxide layers. In addition, depending on the compliance current, the bilayer device could be operated in four different resistance states. Furthermore, the depth profiles of the hourglass-shaped conductive filament of the bilayer device was observed by conductive atomic force microscopy.

  18. Loss of signal transduction and inhibition of lymphocyte locomotion in a ground-based model of microgravity

    Science.gov (United States)

    Sundaresan, Alamelu; Risin, Diana; Pellis, Neal R.; McIntire, L. V. (Principal Investigator)

    2002-01-01

    Inflammatory adherence to, and locomotion through the interstitium is an important component of the immune response. Conditions such as microgravity and modeled microgravity (MMG) severely inhibit lymphocyte locomotion in vitro through gelled type I collagen. We used the NASA rotating wall vessel bioreactor or slow-turning lateral vessel as a prototype for MMG in ground-based experiments. Previous experiments from our laboratory revealed that when lymphocytes (human peripheral blood mononuclear cells [PBMCs]) were first activated with phytohemaglutinin followed by exposure to MMG, locomotory capacity was not affected. In the present study, MMG inhibits lymphocyte locomotion in a manner similar to that observed in microgravity. Phorbol myristate acetate (PMA) treatment of PBMCs restored lost locomotory capacity by a maximum of 87%. Augmentation of cellular calcium flux with ionomycin had no restorative effect. Treatment of lymphocytes with mitomycin C prior to exposure to MMG, followed by PMA, restored locomotion to the same extent as when nonmitomycin C-treated lymphocytes were exposed to MMG (80-87%), suggesting that deoxyribonucleic acid replication is not essential for the restoration of locomotion. Thus, direct activation of protein kinase C (PKC) with PMA was effective in restoring locomotion in MMG comparable to the normal levels seen in Ig cultures. Therefore, in MMG, lymphocyte calcium signaling pathways were functional, with defects occurring at either the level of PKC or upstream of PKC.

  19. Obstacle traversal and self-righting of bio-inspired robots reveal the physics of multi-modal locomotion

    Science.gov (United States)

    Li, Chen; Fearing, Ronald; Full, Robert

    Most animals move in nature in a variety of locomotor modes. For example, to traverse obstacles like dense vegetation, cockroaches can climb over, push across, reorient their bodies to maneuver through slits, or even transition among these modes forming diverse locomotor pathways; if flipped over, they can also self-right using wings or legs to generate body pitch or roll. By contrast, most locomotion studies have focused on a single mode such as running, walking, or jumping, and robots are still far from capable of life-like, robust, multi-modal locomotion in the real world. Here, we present two recent studies using bio-inspired robots, together with new locomotion energy landscapes derived from locomotor-environment interaction physics, to begin to understand the physics of multi-modal locomotion. (1) Our experiment of a cockroach-inspired legged robot traversing grass-like beam obstacles reveals that, with a terradynamically ``streamlined'' rounded body like that of the insect, robot traversal becomes more probable by accessing locomotor pathways that overcome lower potential energy barriers. (2) Our experiment of a cockroach-inspired self-righting robot further suggests that body vibrations are crucial for exploring locomotion energy landscapes and reaching lower barrier pathways. Finally, we posit that our new framework of locomotion energy landscapes holds promise to better understand and predict multi-modal biological and robotic movement.

  20. RESEARCH OF IMPACT OF THE LOADING ON ENDURANCE OF THE FREIGHT LOCOMOTIVE ENGINES

    Directory of Open Access Journals (Sweden)

    Sergejus LEBEDEVAS

    2015-12-01

    Full Text Available The publication reflects the research results of the rationalization of the rolling stock use of JSC LG Lithuanian railways to increase the reliability indicators of the freight diesel locomotive exploitation reliability. The comparative evaluation of the exploited freight diesel locomotive work duration, according to the technical documentation, by using comparative test results and indirect diesel reliability criteria approved in practice. An algorithm of work duration forecasting methodology has been created, as well as a programme complex of mathematic modelling. The differences of the results indicated in the experiment and modelled by computer do not exceed 5 ÷ 7%. The proposed and described methodology of the diesel locomotive exploitation load cycle dynamic indicator reduction, by the use of which the following is achieved: increase of the diesel work duration by 7÷10%, reduction of fuel consumption up to 10%, reduction of the load cycle dynamic indicators (increasing the fatigue stress of parts and units of the diesel by 15÷20%.

  1. Nonlinear dynamics analysis of the spur gear system for railway locomotive

    Science.gov (United States)

    Wang, Junguo; He, Guangyue; Zhang, Jie; Zhao, Yongxiang; Yao, Yuan

    2017-02-01

    Considering the factors such as the nonlinearity backlash, static transmission error and time-varying meshing stiffness, a three-degree-of-freedom torsional vibration model of spur gear transmission system for a typical locomotive is developed, in which the wheel/rail adhesion torque is considered as uncertain but bounded parameter. Meantime, the Ishikawa method is used for analysis and calculation of the time-varying mesh stiffness of the gear pair in meshing process. With the help of bifurcation diagrams, phase plane diagrams, Poincaré maps, time domain response diagrams and amplitude-frequency spectrums, the effects of the pinion speed and stiffness on the dynamic behavior of gear transmission system for locomotive are investigated in detail by using the numerical integration method. Numerical examples reveal various types of nonlinear phenomena and dynamic evolution mechanism involving one-period responses, multi-periodic responses, bifurcation and chaotic responses. Some research results present useful information to dynamic design and vibration control of the gear transmission system for railway locomotive.

  2. Locomotion of bacteria in liquid flow and the boundary layer effect on bacterial attachment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao, E-mail: zhangchao@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Liao, Qiang, E-mail: lqzx@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Chen, Rong, E-mail: rchen@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Zhu, Xun, E-mail: zhuxun@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China)

    2015-06-12

    The formation of biofilm greatly affects the performance of biological reactors, which highly depends on bacterial swimming and attachment that usually takes place in liquid flow. Therefore, bacterial swimming and attachment on flat and circular surfaces with the consideration of flow was studied experimentally. Besides, a mathematical model comprehensively combining bacterial swimming and motion with flow is proposed for the simulation of bacterial locomotion and attachment in flow. Both experimental and theoretical results revealed that attached bacteria density increases with decreasing boundary layer thickness on both flat and circular surfaces, the consequence of which is inherently related to the competition between bacterial swimming and the non-slip motion with flow evaluated by the Péclet number. In the boundary layer, where the Péclet number is relatively higher, bacterial locomotion mainly depends on bacterial swimming. Thinner boundary layer promotes bacterial swimming towards the surface, leading to higher attachment density. To enhance the performance of biofilm reactors, it is effective to reduce the boundary layer thickness on desired surfaces. - Highlights: • Study of bacterial locomotion in flow as an early stage in biofilm formation. • Mathematical model combining bacterial swimming and the motion with flow. • Boundary layer plays a key role in bacterial attachment under flow condition. • The competition between bacterial swimming and the motion with flow is evaluated.

  3. Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat.

    Science.gov (United States)

    Nielsen, J B; Conway, B A; Halliday, D M; Perreault, M-C; Hultborn, H

    2005-11-15

    The basic locomotor rhythm in the cat is generated by a neuronal network in the spinal cord. The exact organization of this network and its drive to the spinal motoneurones is unknown. The purpose of the present study was to use time (cumulant density) and frequency domain (coherence) analysis to examine the organization of the last order drive to motoneurones during fictive locomotion (evoked by application of nialamide and dihydroxyphenylalanine (DOPA)) in the spinal cat. In all cats, narrow central synchronization peaks (half-width synchronization was observed between the individual intracellular recordings and the ENGs recorded from nerves of the same pool and of close synergists. Recordings from 34 pairs of motoneurones (10 pairs belonged to the same motor pool, 11 pairs to close synergists and 13 pairs to antagonistic pools) failed to reveal any short-lasting synchronization. These data demonstrate that short-term synchronization during fictive locomotion is relatively weak and is restricted to close synergists. In addition, coherence analysis failed to identify any specific rhythmic component in the locomotor drive that could be associated with this synchronization. These results resemble findings obtained during human treadmill walking and imply that the spinal interneurones participating in the generation of the locomotor rhythm are themselves weakly synchronized. The restricted synchronization within the locomotor drive to motoneuronal pools may be a feature of the locomotor generating networks that is related to the ability of these networks to produce highly adaptive patterns of muscle activity during locomotion.

  4. Caterpillar locomotion-inspired valveless pneumatic micropump using a single teardrop-shaped elastomeric membrane

    KAUST Repository

    So, Hongyun; Pisano, Albert P.; Seo, Young Ho

    2014-01-01

    This paper presents a microfluidic pump operated by an asymmetrically deformed membrane, which was inspired by caterpillar locomotion. Almost all mechanical micropumps consist of two major components of fluid halting and fluid pushing parts, whereas the proposed caterpillar locomotion-inspired micropump has only a single, bilaterally symmetric membrane-like teardrop shape. A teardrop-shaped elastomeric membrane was asymmetrically deformed and then consecutively touched down to the bottom of the chamber in response to pneumatic pressure, thus achieving fluid pushing. Consecutive touchdown motions of the teardrop-shaped membrane mimicked the propagation of a caterpillar's hump during its locomotory gait. The initial touchdown motion of the teardrop-shaped membrane at the centroid worked as a valve that blocked the inlet channel, and then, the consecutive touchdown motions pushed fluid in the chamber toward the tail of the chamber connected to the outlet channel. The propagation of the touchdown motion of the teardrop-shaped membrane was investigated using computational analysis as well as experimental studies. This caterpillar locomotion-inspired micropump composed of only a single membrane can provide new opportunities for simple integration of microfluidic systems. © the Partner Organisations 2014.

  5. Locomotion of bacteria in liquid flow and the boundary layer effect on bacterial attachment

    International Nuclear Information System (INIS)

    Zhang, Chao; Liao, Qiang; Chen, Rong; Zhu, Xun

    2015-01-01

    The formation of biofilm greatly affects the performance of biological reactors, which highly depends on bacterial swimming and attachment that usually takes place in liquid flow. Therefore, bacterial swimming and attachment on flat and circular surfaces with the consideration of flow was studied experimentally. Besides, a mathematical model comprehensively combining bacterial swimming and motion with flow is proposed for the simulation of bacterial locomotion and attachment in flow. Both experimental and theoretical results revealed that attached bacteria density increases with decreasing boundary layer thickness on both flat and circular surfaces, the consequence of which is inherently related to the competition between bacterial swimming and the non-slip motion with flow evaluated by the Péclet number. In the boundary layer, where the Péclet number is relatively higher, bacterial locomotion mainly depends on bacterial swimming. Thinner boundary layer promotes bacterial swimming towards the surface, leading to higher attachment density. To enhance the performance of biofilm reactors, it is effective to reduce the boundary layer thickness on desired surfaces. - Highlights: • Study of bacterial locomotion in flow as an early stage in biofilm formation. • Mathematical model combining bacterial swimming and the motion with flow. • Boundary layer plays a key role in bacterial attachment under flow condition. • The competition between bacterial swimming and the motion with flow is evaluated

  6. Influence of AC system design on the realisation of tractive efforts by high adhesion locomotives

    Science.gov (United States)

    Spiryagin, Maksym; Wolfs, Peter; Cole, Colin; Stichel, Sebastian; Berg, Mats; Manfred, Plöchl

    2017-08-01

    The main task for heavy haul railway operators is to reduce the cost of exported minerals and enhance the long-term viability of rail transport operations through increasing productivity by running longer and heavier trains. The common opinion is that this is achievable by means of implementation of high adhesion locomotives with advanced AC traction technologies. Modern AC high adhesion locomotives are very complex mechatronic systems and can be designed with two alternative traction topologies of either bogie or individual axle controls. This paper describes a modelling approach for these two types of AC traction systems with the application of an advanced co-simulation methodology, where an electrical system and a traction algorithm are modelled in Matlab/Simulink, and a mechanical system is modelled in a multibody software package. Although the paper concentrates on the analysis of the functioning for these two types of traction control systems, the choice of reference slip values also has an influence on the performance of both systems. All these design variations and issues have been simulated for various adhesion conditions at the wheel-rail interface and their influence on the high traction performance of a locomotive equipped with two three-axle bogies has been discussed.

  7. A survey report for the biped locomotion model under external force

    International Nuclear Information System (INIS)

    Kato, Ichiro; Takanishi, Atsuo; Kume, Etsuo.

    1993-10-01

    A mechanical design study of biped locomotion robots is being performed at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. We have developed the simulation software which has capability of obtaining several types of stable motions for straight walking in terms of design tools. In addition, we are studying more complex walking patterns such as turning. However, in order to realize the robustness of walking, it is also necessary for the robot to have a capability of walking under external force as a disturbance which is caused by touching an object and so on. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report for the biped locomotion model under external force: the WL-12RIII/IV designed and developed at Waseda University. This report includes the machine model, control system, control method and results of walking experiments. (author)

  8. Highlighting the harmonic regime generated by electric locomotives equipped with DC motors

    Science.gov (United States)

    Baciu, I.; Cunţan, C. D.

    2018-01-01

    The paper presents the results of measurements made using the C.A. 8334 power quality analyzer on an electric locomotive equipped with DC motors. We carried out determinations of the current-voltage regime using a locomotive motor. The harmonic regime of the other motors being identical to the analysed one, we could easily deduce the effects caused by the entire locomotive. The data measured with the analyzer were firstly transferred into a computer system using the Qualistar software, followed by data processing in Excel, enabling therefore a graphical representation of the characteristic parameters of power quality. Based on the acquired data, we determined the power factor, as well as the active, reactive and apparent power. The measurements revealed high values of the current harmonics, fact that required some measures to be taken for reducing the values of these harmonics. For this, we ran a simulation using the PSCAD/EMTDC software, by introducing LC filters in tune with the harmonic frequencies. The result was a significant reduction in the harmonic regime, either in the harmonics values or the power factor and reactive power.

  9. Caterpillar locomotion-inspired valveless pneumatic micropump using a single teardrop-shaped elastomeric membrane

    KAUST Repository

    So, Hongyun

    2014-01-01

    This paper presents a microfluidic pump operated by an asymmetrically deformed membrane, which was inspired by caterpillar locomotion. Almost all mechanical micropumps consist of two major components of fluid halting and fluid pushing parts, whereas the proposed caterpillar locomotion-inspired micropump has only a single, bilaterally symmetric membrane-like teardrop shape. A teardrop-shaped elastomeric membrane was asymmetrically deformed and then consecutively touched down to the bottom of the chamber in response to pneumatic pressure, thus achieving fluid pushing. Consecutive touchdown motions of the teardrop-shaped membrane mimicked the propagation of a caterpillar\\'s hump during its locomotory gait. The initial touchdown motion of the teardrop-shaped membrane at the centroid worked as a valve that blocked the inlet channel, and then, the consecutive touchdown motions pushed fluid in the chamber toward the tail of the chamber connected to the outlet channel. The propagation of the touchdown motion of the teardrop-shaped membrane was investigated using computational analysis as well as experimental studies. This caterpillar locomotion-inspired micropump composed of only a single membrane can provide new opportunities for simple integration of microfluidic systems. © the Partner Organisations 2014.

  10. Minimally Actuated Walking: Identifying Core Challenges to Economical Legged Locomotion Reveals Novel Solutions

    Directory of Open Access Journals (Sweden)

    Ryan T Schroeder

    2018-05-01

    Full Text Available Terrestrial organisms adept at locomotion employ strut-like legs for economical and robust movement across the substrate. Although it is relatively easy to observe and analyze details of the solutions these organic systems have arrived at, it is not as easy to identify the problems these movement strategies have solved. As such, it is useful to investigate fundamental challenges that effective legged locomotion overcomes in order to understand why the mechanisms employed by biological systems provide viable solutions to these challenges. Such insight can inform the design and development of legged robots that may eventually match or exceed animal performance. In the context of human walking, we apply control optimization as a design strategy for simple bipedal walking machines with minimal actuation. This approach is used to discuss key facilitators of energetically efficient locomotion in simple bipedal walkers. Furthermore, we extrapolate the approach to a novel application—a theoretical exoskeleton attached to the trunk of a human walker—to demonstrate how coordinated efforts between bipedal actuation and a machine oscillator can potentially alleviate a meaningful portion of energetic exertion associated with leg function during human walking.

  11. Mutually opposing forces during locomotion can eliminate the tradeoff between maneuverability and stability

    Science.gov (United States)

    Cowan, Noah; Sefati, Shahin; Neveln, Izaak; Roth, Eatai; Mitchell, Terence; Snyder, James; Maciver, Malcolm; Fortune, Eric

    A surprising feature of animal locomotion is that organisms typically produce substantial forces in directions other than what is necessary to move the animal through its environment, such as perpendicular to, or counter to, the direction of travel. The effect of these forces has been difficult to observe because they are often mutually opposing and therefore cancel out. Using a combination of robotic physical modeling, computational modeling, and biological experiments, we discovered that these forces serve an important role: to simplify and enhance the control of locomotion. Specifically, we examined a well-suited model system, the glass knifefish Eigenmannia virescens, which produces mutually opposing forces during a hovering behavior. By systematically varying the locomotor parameters of our biomimetic robot, and measuring the resulting forces and kinematics, we demonstrated that the production and differential control of mutually opposing forces is a strategy that generates passive stabilization while simultaneously enhancing maneuverability. Mutually opposing forces during locomotion are widespread across animal taxa, and these results indicate that such forces can eliminate the tradeoff between stability and maneuverability, thereby simplifying robotic and neural control.

  12. Cellullar insights into cerebral cortical development: focusing on the locomotion mode of neuronal migration

    Directory of Open Access Journals (Sweden)

    Takeshi eKawauchi

    2015-10-01

    Full Text Available The mammalian brain consists of numerous compartments that are closely connected with each other via neural networks, comprising the basis of higher order brain functions. The highly specialized structure originates from simple pseudostratified neuroepithelium-derived neural progenitors located near the ventricle. A long journey by neurons from the ventricular side is essential for the formation of a sophisticated brain structure, including a mammalian-specific six-layered cerebral cortex. Neuronal migration consists of several contiguous steps, but the locomotion mode comprises a large part of the migration. The locomoting neurons exhibit unique features; a radial glial fiber-dependent migration requiring the endocytic recycling of N-cadherin and a neuron-specific migration mode with dilation/swelling formation that requires the actin and microtubule organization possibly regulated by cyclin-dependent kinase 5 (Cdk5, Dcx, p27kip1, Rac1 and POSH. Here I will introduce the roles of various cellular events, such as cytoskeletal organization, cell adhesion and membrane trafficking, in the regulation of the neuronal migration, with particular focus on the locomotion mode.

  13. The Relationship between Locomotive Syndrome and Depression in Community-Dwelling Elderly People

    Directory of Open Access Journals (Sweden)

    Misa Nakamura

    2017-01-01

    Full Text Available Locomotive syndrome (LS is a concept that refers to the condition of people requiring healthcare services because of problems associated with locomotion. Depression is a major psychiatric disease among the elderly, in addition to dementia. The purpose of this study was to determine the association between LS and depression. The study participants were 224 healthy elderly volunteers living in a rural area in Japan. LS was defined as scores ≥ 16 on the 25-question Geriatric Locomotive Function Scale (GLFS-25. Depression was defined as scores ≥ 5 on the 15-item Geriatric Depression Scale (GDS-15. Height and body weight were measured. The prevalence of LS and depression was 13.9% and 24.2%, respectively. Compared with the non-LS group, the LS group was older, was shorter, had a higher BMI, and had higher GDS-15 scores. Logistic regression analysis showed that participants with GDS-15 scores ≥ 6 had higher odds for LS than those with GDS-15 scores < 6 (odds ratio [OR] = 4.22. Conversely, the depression group had higher GLFS-25 scores than the nondepression group. Participants with GLFS-25 scores ≥ 5 had higher odds for depression than those with GLFS-25 scores < 5 (OR = 4.53. These findings suggest that there is a close relationship between LS and depression.

  14. Sustained Treatment with Insulin Detemir in Mice Alters Brain Activity and Locomotion.

    Directory of Open Access Journals (Sweden)

    Tina Sartorius

    Full Text Available Recent studies have identified unique brain effects of insulin detemir (Levemir®. Due to its pharmacologic properties, insulin detemir may reach higher concentrations in the brain than regular insulin. This might explain the observed increased brain stimulation after acute insulin detemir application but it remained unclear whether chronic insulin detemir treatment causes alterations in brain activity as a consequence of overstimulation.In mice, we examined insulin detemir's prolonged brain exposure by continuous subcutaneous (s.c. application using either micro-osmotic pumps or daily s.c. injections and performed continuous radiotelemetric electrocorticography and locomotion recordings.Acute intracerebroventricular injection of insulin detemir activated cortical and locomotor activity significantly more than regular insulin in equimolar doses (0.94 and 5.63 mU in total, suggesting an enhanced acute impact on brain networks. However, given continuously s.c., insulin detemir significantly reduced cortical activity (theta: 21.3±6.1% vs. 73.0±8.1%, P<0.001 and failed to maintain locomotion, while regular insulin resulted in an increase of both parameters.The data suggest that permanently-increased insulin detemir levels in the brain convert its hyperstimulatory effects and finally mediate impairments in brain activity and locomotion. This observation might be considered when human studies with insulin detemir are designed to target the brain in order to optimize treatment regimens.

  15. Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats

    Directory of Open Access Journals (Sweden)

    Braniff de la Torre Valdovinos

    2016-01-01

    Full Text Available We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI, in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD of the pendulum-like movements (PLM during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats.

  16. Geckos significantly alter foot orientation to facilitate adhesion during downhill locomotion.

    Science.gov (United States)

    Birn-Jeffery, Aleksandra V; Higham, Timothy E

    2014-10-01

    Geckos employ their adhesive system when moving up an incline, but the directionality of the system may limit function on downhill surfaces. Here, we use a generalist gecko to test whether limb modulation occurs on downhill slopes to allow geckos to take advantage of their adhesive system. We examined three-dimensional limb kinematics for geckos moving up and down a 45° slope. Remarkably, the hind limbs were rotated posteriorly on declines, resulting in digit III of the pes facing a more posterior direction (opposite to the direction of travel). No significant changes in limb orientation were found in any other condition. This pes rotation leads to a dramatic shift in foot function that facilitates the use of the adhesive system as a brake/stabilizer during downhill locomotion and, although this rotation is not unique to geckos, it is significant for the deployment of adhesion. Adhesion is not just advantageous for uphill locomotion but can be employed to help deal with the effects of gravity during downhill locomotion, highlighting the incredible multi-functionality of this key innovation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit has a light emitting diode which supplies light to a photo-transistor, the light being interrupted from time to time. When the photo-transistor is illuminated, current builds up and when this current reaches a predetermined value, a trigger circuit changes state. The peak output of the photo-transistor is measured and the trigger circuit is arranged to change state when the output of the device is a set proportion of the peak output, so as to allow for aging of the components. The circuit is designed to control the ignition system in an automobile engine.

  18. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit includes a light emitting diode which from time to time illuminates a photo-transistor, the photo-transistor serving when its output reaches a predetermined value to operate a trigger circuit. In order to allow for aging of the components, the current flow through the diode is increased when the output from the transistor falls below a known level. Conveniently, this is achieved by having a transistor in parallel with the diode, and turning the transistor off when the output from the phototransistor becomes too low. The circuit is designed to control the ignition system in an automobile engine.

  19. Manual and automatic locomotion scoring systems in dairy cows: a review.

    Science.gov (United States)

    Schlageter-Tello, Andrés; Bokkers, Eddie A M; Koerkamp, Peter W G Groot; Van Hertem, Tom; Viazzi, Stefano; Romanini, Carlos E B; Halachmi, Ilan; Bahr, Claudia; Berckmans, Daniël; Lokhorst, Kees

    2014-09-01

    The objective of this review was to describe, compare and evaluate agreement, reliability, and validity of manual and automatic locomotion scoring systems (MLSSs and ALSSs, respectively) used in dairy cattle lameness research. There are many different types of MLSSs and ALSSs. Twenty-five MLSSs were found in 244 articles. MLSSs use different types of scale (ordinal or continuous) and different gait and posture traits need to be observed. The most used MLSS (used in 28% of the references) is based on asymmetric gait, reluctance to bear weight, and arched back, and is scored on a five-level scale. Fifteen ALSSs were found that could be categorized according to three approaches: (a) the kinetic approach measures forces involved in locomotion, (b) the kinematic approach measures time and distance of variables associated to limb movement and some specific posture variables, and (c) the indirect approach uses behavioural variables or production variables as indicators for impaired locomotion. Agreement and reliability estimates were scarcely reported in articles related to MLSSs. When reported, inappropriate statistical methods such as PABAK and Pearson and Spearman correlation coefficients were commonly used. Some of the most frequently used MLSSs were poorly evaluated for agreement and reliability. Agreement and reliability estimates for the original four-, five- or nine-level MLSS, expressed in percentage of agreement, kappa and weighted kappa, showed large ranges among and sometimes also within articles. After the transformation into a two-level scale, agreement and reliability estimates showed acceptable estimates (percentage of agreement ≥ 75%; kappa and weighted kappa ≥ 0.6), but still estimates showed a large variation between articles. Agreement and reliability estimates for ALSSs were not reported in any article. Several ALSSs use MLSSs as a reference for model calibration and validation. However, varying agreement and reliability estimates of MLSSs make a

  20. Cognitive impairment associated with locomotive syndrome in community-dwelling elderly women in Japan

    Directory of Open Access Journals (Sweden)

    Nakamura M

    2017-09-01

    Full Text Available Misa Nakamura,1 Fumie Tazaki,1 Kazuki Nomura,1 Taeko Takano,1 Masashi Hashimoto,1 Hiroshi Hashizume,2 Ichiro Kamei1 1Department of Rehabilitation, Osaka Kawasaki Rehabilitation University, Kaizuka, Osaka, Japan; 2Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, Japan Abstract: In our worldwide aging society, elderly people should maintain cognitive and physical function to help avoid health problems. Dementia is a major brain disease among elderly people, and is caused by cognitive impairment. The locomotive syndrome (LS refers to a condition in which people require healthcare services because of problems associated with locomotion. The purpose of this study was to determine the association between cognitive impairment and LS. Study participants were 142 healthy elderly female volunteers living in a rural area in Japan. Cognitive function was assessed using the Mini-Mental State Examination (MMSE. A score of ≤26 points on the MMSE was used to indicate categorically defined poor cognitive performance (cognitive impairment. The LS was defined by a score ≥16 points, and non-LS as <16 points, on the 25-question Geriatric Locomotive Function Scale (GLFS-25. Twenty-one participants (14.8% had an MMSE score ≤26, and 19.0% were found to have LS. Compared with the MMSE >26 group, the ≤26 group was significantly older, had a higher percentage of body fat, and a higher GLFS-25 score. Those with LS were significantly older, had a higher body mass index, a higher percentage of body fat, and a lower MMSE score. Participants in the LS group had higher odds of cognitive impairment than those without LS [odds ratio (OR =3.08] by logistic regression analysis adjusted for age. Furthermore, participants with GLFS-25 scores ≥6 had higher odds of cognitive impairment than those with a GLFS-25 score <6 by logistic regression analysis adjusted for both age (OR =4.44, and age and percent body fat (OR =4.12. These findings

  1. Know-How on design of switching regulator

    International Nuclear Information System (INIS)

    1985-08-01

    This book introduces switching regulator from base to application, which deals with fundamentals of switching regulator such as the reason of boom about switching regulator, understanding simple circuit without electric transformer and decision of circuit type with input voltage and output voltage, configuration and characteristic of switching regulator, a concrete design of switching regulator, pulse width control circuit and protection circuit, concrete circuit examples of switching power and the point of switching regulator.

  2. Stateless multicast switching in software defined networks

    OpenAIRE

    Reed, Martin J.; Al-Naday, Mays; Thomos, Nikolaos; Trossen, Dirk; Petropoulos, George; Spirou, Spiros

    2016-01-01

    Multicast data delivery can significantly reduce traffic in operators' networks, but has been limited in deployment due to concerns such as the scalability of state management. This paper shows how multicast can be implemented in contemporary software defined networking (SDN) switches, with less state than existing unicast switching strategies, by utilising a Bloom Filter (BF) based switching technique. Furthermore, the proposed mechanism uses only proactive rule insertion, and thus, is not l...

  3. Monitoring Mellanox Infiniband SX6036 switches

    CERN Document Server

    Agapiou, Marinos

    2017-01-01

    The SX6036 switches addressed by my project, are part of a fully non-blocking fat-tree cluster consisting of 72 servers and 6 Mellanox SX6036 Infiniband switches. My project is about retrieving the appropriate metrics from the Infiniband switch cluster, ingesting the data to Collectd and after my data are being transfered to CERN Database, they are being visualized via Grafana Dashboards.

  4. Optical switches based on surface plasmons

    International Nuclear Information System (INIS)

    Chen Cong; Wang Pei; Yuan Guanghui; Wang Xiaolei; Min Changjun; Deng Yan; Lu Yonghua; Ming Hai

    2008-01-01

    Great attention is being paid to surface plasmons (SPs) because of their potential applications in sensors, data storage and bio-photonics. Recently, more and more optical switches based on surface plasmon effects have been demonstrated either by simulation or experimentally. This article describes the principles, advantages and disadvantages of various types of optical switches based on SPs, in particular the all-optical switches. (authors)

  5. A new switched power linac structure

    International Nuclear Information System (INIS)

    Villa, F.

    1989-03-01

    A new pulse power structure has been described that utilizes an easily accessible rectilinear switch. The new structure is more ''forgiving'' (as far as risetime is concerned) than the radial line transformer, and contains fewer switching structures/unit length. The combination of the new structure with the switch proposed seems to offer interesting possibilities for a future linear collider. 13 refs., 6 figs., 2 tabs

  6. Switching induced oscillations in the logistic map

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Makisha P.S. [Department of Chemistry, Williams College, Williamstown, MA 01267 (United States); Peacock-Lopez, Enrique, E-mail: epeacock@williams.ed [Department of Chemistry, Williams College, Williamstown, MA 01267 (United States)

    2010-02-08

    In ecological modeling, seasonality can be represented as a switching between different environmental conditions. This switching strategy can be related to the so-called Parrondian games, where the alternation of two losing games yield a winning game. Hence we can consider two dynamics that, by themselves, yield undesirable behaviors, but when alternated yield a desirable oscillatory behavior. In this case, we also consider a noisy switching strategy and find that the desirable oscillatory behavior prevails.

  7. Ultrafast pulse generation in photoconductive switches

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Dykaar, D. R.

    1996-01-01

    Carrier and field dynamics in photoconductive switches are investigated by electrooptic sampling and voltage-dependent reflectivity measurements. We show that the nonuniform field distribution due to the two-dimensional nature of coplanar photoconductive switches, in combination with the large di...... difference in the mobilities of holes and electrons, determine the pronounced polarity dependence. Our measurements indicate that the pulse generation mechanism is a rapid voltage breakdown across the photoconductive switch and not a local field breakdown...

  8. A magnetically switched kicker for proton extraction

    International Nuclear Information System (INIS)

    Dinkel, J.; Biggs, J.

    1989-03-01

    The application of magnetic current amplification and switching techniques to the generation of precise high current pulses for switching magnets is described. The square loop characteristic of Metglas tape wound cores at high excitation levels provides excellent switching characteristics for microsecond pulses. The rugged and passive nature of this type pulser makes it possible to locate the final stages of amplification at the load for maximum efficiency. 12 refs., 8 figs

  9. Environmental and cow-related factors affect cow locomotion and can cause misclassification in lameness detection systems.

    Science.gov (United States)

    Van Nuffel, A; Van De Gucht, T; Saeys, W; Sonck, B; Opsomer, G; Vangeyte, J; Mertens, K C; De Ketelaere, B; Van Weyenberg, S

    2016-09-01

    To tackle the high prevalence of lameness, techniques to monitor cow locomotion are being developed in order to detect changes in cows' locomotion due to lameness. Obviously, in such lameness detection systems, alerts should only respond to locomotion changes that are related to lameness. However, other environmental or cow factors can contribute to locomotion changes not related to lameness and hence, might cause false alerts. In this study the effects of wet surfaces, dark environment, age, production level, lactation and gestation stage on cow locomotion were investigated. Data was collected at Institute for Agricultural and Fisheries Research research farm (Melle, Belgium) during a 5-month period. The gait variables of 30 non-lame and healthy Holstein cows were automatically measured every day. In dark environments and on wet walking surfaces cows took shorter, more asymmetrical strides with less step overlap. In general, older cows had a more asymmetrical gait and they walked slower with more abduction. Lactation stage or gestation stage also showed significant association with asymmetrical and shorter gait and less step overlap probably due to the heavy calf in the uterus. Next, two lameness detection algorithms were developed to investigate the added value of environmental and cow data into detection models. One algorithm solely used locomotion variables and a second algorithm used the same locomotion variables and additional environmental and cow data. In the latter algorithm only age and lactation stage together with the locomotion variables were withheld during model building. When comparing the sensitivity for the detection of non-lame cows, sensitivity increased by 10% when the cow data was added in the algorithm (sensitivity was 70% and 80% for the first and second algorithm, respectively). Hence, the number of false alerts for lame cows that were actually non-lame, decreased. This pilot study shows that using knowledge on influencing factors on cow

  10. Atomic battery with beam switching

    International Nuclear Information System (INIS)

    Edling, E.A.; McKenna, R.P.; Peterick, E.Th. Jr.; Trexler, F.D.

    1984-01-01

    An electric power generating apparatus that is powered primarily by the emission of electrically charged particles from radio-active materials enclosed in an evacuated vessel of glass or the like. An arrangement of reflecting electrodes causes a beam of particles to switch back and forth at a high frequency between two collecting electrodes that are connected to a resonating tuned primary circuit consisting of an inductor with resonating capacitor. The reflecting electrodes are energized in the proper phase relationship to the collecting electrodes to insure sustained oscillation by means of a secondary winding coupled inductively to the primary winding and connected to the reflecting electrodes. Power may be drawn from the circuit at a stepped down voltage from a power take-off winding that is coupled to the primary winding. The disclosure also describes a collecting electrode arrangement consisting of multiple spatially separated electrodes which together serve to capture a maximum of the available particle energy. A self-starting arrangement for start of oscillations is described. A specially adapted version of the invention utilizes two complementary beams of oppositely charged particles which are switched alternatingly between the collecting electrodes

  11. Atomic crystals resistive switching memory

    International Nuclear Information System (INIS)

    Liu Chunsen; Zhang David Wei; Zhou Peng

    2017-01-01

    Facing the growing data storage and computing demands, a high accessing speed memory with low power and non-volatile character is urgently needed. Resistive access random memory with 4F 2 cell size, switching in sub-nanosecond, cycling endurances of over 10 12 cycles, and information retention exceeding 10 years, is considered as promising next-generation non-volatile memory. However, the energy per bit is still too high to compete against static random access memory and dynamic random access memory. The sneak leakage path and metal film sheet resistance issues hinder the further scaling down. The variation of resistance between different devices and even various cycles in the same device, hold resistive access random memory back from commercialization. The emerging of atomic crystals, possessing fine interface without dangling bonds in low dimension, can provide atomic level solutions for the obsessional issues. Moreover, the unique properties of atomic crystals also enable new type resistive switching memories, which provide a brand-new direction for the resistive access random memory. (topical reviews)

  12. Heat switch technology for cryogenic thermal management

    Science.gov (United States)

    Shu, Q. S.; Demko, J. A.; E Fesmire, J.

    2017-12-01

    Systematic review is given of development of novel heat switches at cryogenic temperatures that alternatively provide high thermal connection or ideal thermal isolation to the cold mass. These cryogenic heat switches are widely applied in a variety of unique superconducting systems and critical space applications. The following types of heat switch devices are discussed: 1) magnetic levitation suspension, 2) shape memory alloys, 3) differential thermal expansion, 4) helium or hydrogen gap-gap, 5) superconducting, 6) piezoelectric, 7) cryogenic diode, 8) magneto-resistive, and 9) mechanical demountable connections. Advantages and limitations of different cryogenic heat switches are examined along with the outlook for future thermal management solutions in materials and cryogenic designs.

  13. Stochastic multistep polarization switching in ferroelectrics

    Science.gov (United States)

    Genenko, Y. A.; Khachaturyan, R.; Schultheiß, J.; Ossipov, A.; Daniels, J. E.; Koruza, J.

    2018-04-01

    Consecutive stochastic 90° polarization switching events, clearly resolved in recent experiments, are described by a nucleation and growth multistep model. It extends the classical Kolmogorov-Avrami-Ishibashi approach and includes possible consecutive 90°- and parallel 180° switching events. The model predicts the results of simultaneous time-resolved macroscopic measurements of polarization and strain, performed on a tetragonal Pb (Zr ,Ti ) O3 ceramic in a wide range of electric fields over a time domain of seven orders of magnitude. It allows the determination of the fractions of individual switching processes, their characteristic switching times, activation fields, and respective Avrami indices.

  14. The increased importance of sector switching

    DEFF Research Database (Denmark)

    Frederiksen, Anders; Hansen, Jesper Rosenberg

    2017-01-01

    Sector switching is an important phenomenon that casts light on public–private differences. Yet our knowledge about its prevalence and trends is limited. We study sector switching using unique Danish register-based employer–employee data covering more than 25 years. We find that sector switching...... constitutes 18.5% of all job-to-job mobility, and the trend is increasing both from public to private and from private to public. Sector switching is also generally increasing for middle managers, but for administrative professionals only the flows from private to public increase and for top managers only...... the flows from public to private increase....

  15. Wireless Nanoionic-Based Radio Frequency Switch

    Science.gov (United States)

    Nessel, James A. (Inventor); Miranda, Felix A (Inventor)

    2017-01-01

    A nanoionic switch connected to one or more rectenna modules is disclosed. The rectenna module is configured to receive a wireless signal and apply a first bias to change a state of the nanoionic switch from a first state to a second state. The rectenna module can receive a second wireless signal and apply a second bias to change the nanoionic switch from the second state back to the first state. The first bias is generally opposite of the first bias. The rectenna module accordingly permits operation of the nanoionic switch without onboard power.

  16. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  17. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  18. Simplified design of switching power supplies

    CERN Document Server

    Lenk, John

    1995-01-01

    * Describes the operation of each circuit in detail * Examines a wide selection of external components that modify the IC package characteristics * Provides hands-on, essential information for designing a switching power supply Simplified Design of Switching Power Supplies is an all-inclusive, one-stop guide to switching power-supply design. Step-by-step instructions and diagrams render this book essential for the student and the experimenter, as well as the design professional. Simplified Design of Switching Power Supplies concentrates on the use of IC regulators. All popular forms of swit

  19. Demonstration of Ultra-Fast Switching in Nano metallic Resistive Switching Memory Devices

    International Nuclear Information System (INIS)

    Yang, Y.

    2016-01-01

    Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nano metallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic RC time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nano metallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.

  20. Neural Control and Adaptive Neural Forward Models for Insect-like, Energy-Efficient, and Adaptable Locomotion of Walking Machines

    Directory of Open Access Journals (Sweden)

    Poramate eManoonpong

    2013-02-01

    Full Text Available Living creatures, like walking animals, have found fascinating solutions for the problem of locomotion control. Their movements show the impression of elegance including versatile, energy-efficient, and adaptable locomotion. During the last few decades, roboticists have tried to imitate such natural properties with artificial legged locomotion systems by using different approaches including machine learning algorithms, classical engineering control techniques, and biologically-inspired control mechanisms. However, their levels of performance are still far from the natural ones. By contrast, animal locomotion mechanisms seem to largely depend not only on central mechanisms (central pattern generators, CPGs and sensory feedback (afferent-based control but also on internal forward models (efference copies. They are used to a different degree in different animals. Generally, CPGs organize basic rhythmic motions which are shaped by sensory feedback while internal models are used for sensory prediction and state estimations. According to this concept, we present here adaptive neural locomotion control consisting of a CPG mechanism with neuromodulation and local leg control mechanisms based on sensory feedback and adaptive neural forward models with efference copies. This neural closed-loop controller enables a walking machine to perform a multitude of different walking patterns including insect-like leg movements and gaits as well as energy-efficient locomotion. In addition, the forward models allow the machine to autonomously adapt its locomotion to deal with a change of terrain, losing of ground contact during stance phase, stepping on or hitting an obstacle during swing phase, leg damage, and even to promote cockroach-like climbing behavior. Thus, the results presented here show that the employed embodied neural closed-loop system can be a powerful way for developing robust and adaptable machines.