WorldWideScience

Sample records for displacer driving mechanism

  1. Analysis of the dynamics of a nutating body. [numerical analysis of displacement, velocity, and acceleration of point on mechanical drives

    Science.gov (United States)

    Anderson, W. J.

    1974-01-01

    The equations for the displacement, velocity, and acceleration of a point in a nutating body are developed. These are used to derive equations for the inertial moment developed by a nutating body of arbitrary shape. Calculations made for a previously designed nutating plate transmission indicate that that device is severely speed limited because of the very high magnitude inertial moment.

  2. Turbulent current drive mechanisms

    Science.gov (United States)

    McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

    2017-08-01

    Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm's law and hence provide an ideal means for driving deviations from neoclassical predictions.

  3. Split-Stirling-cycle displacer linear-electric drive

    Science.gov (United States)

    Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

    1983-01-01

    The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

  4. Rod drive and latching mechanism

    International Nuclear Information System (INIS)

    Veronesi, L.; Sherwood, D.G.

    1982-01-01

    Hydraulic drive and latching mechanisms for driving reactivity control mechanisms in nuclear reactors are described. Preferably, the pressurized reactor coolant is utilized to raise the drive rod into contact with and to pivot the latching mechanism so as to allow the drive rod to pass the latching mechanism. The pressure in the housing may then be equalized which allows the drive rod to move downwardly into contact with the latching mechanism but to hold the shaft in a raised position with respect to the reactor core. Once again, the reactor coolant pressure may be utilized to raise the drive rod and thus pivot the latching mechanism so that the drive rod passes above the latching mechanism. Again, the mechanism pressure can be equalized which allows the drive rod to fall and pass by the latching mechanism so that the drive rod approaches the reactor core. (author)

  5. Failure analysis and structure optimization of the connecting thread of driving shaft in positive displacement motor

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhu

    2016-05-01

    Full Text Available Due to high efficiency in helping breaking rocks, positive displacement motor has a widespread application in the field of oil and gas drilling engineering. However, service life of positive displacement motor becomes shorter resulting from failure of the driving shaft thread. The three-dimensional simulation model of driving shaft’s connecting thread has been developed based on the principle of virtual work, Von Mises yield criterion, and contact nonlinear theory. This article has put forward the plan to optimize structure of driving shaft with straight thread based on the design principle of double-shouldered thread; besides, fatigue life of driving shaft with straight thread before and after optimization has been assessed by resorting to the multiaxial fatigue principle and Brown–Miller critical plane rule. In line with research results, mechanical properties of driving shaft with straight thread are superior to those of driving shaft with taper thread. Under the load of axial drill pressure with fluctuation and alternating torque, fatigue life of driving shaft with straight thread after optimization is greatly improved. This article has not only provided basis for optimizing connecting thread of driving shaft but also boasts of high engineering value for improving service life of positive displacement motor.

  6. Control rod driving mechanisms

    International Nuclear Information System (INIS)

    Maejima, Yoshinori.

    1986-01-01

    Purpose: To conduct reactor scram by an external signal and, also by a signal for the abnormal temperature from a temperature detector in the nuclear reactor. Constitution: Control rod driving mechanisms magnetically coupling the extension pipe with the elevating mechanism above the reactor core and the holding magnet, and retains a control rod to the lower portion of the extension pipe by way of a latch mechanism. The temperature detector is immersed in reactor coolants. If the temperature of the coolants rises abnormally, bimetal contacts of the temperature detector are opened to interrupt the current supply to the holding electromagnet. Then, the extension pipe released from the magnetic coupling is lowered and the control rod free from latch is rapidly dropped and inserted into the reactor core. Since this procedure is carried out for all of the control rods, the reactor scram can be attained. The feature of this invention resides in that the reactor scram can be attained also by the signal of the reactor core itself even if the signal system for the external signals should be failed. (Horiuchi, T.)

  7. Borehole tool outrigger arm displacement control mechanism

    International Nuclear Information System (INIS)

    Lee, A.G.

    1985-01-01

    As the outrigger arms of a borehole logging tool are flexed inwardly and outwardly according to the diameter of the borehole opening through which they pass, the corresponding axial displacements of the ends of the arms are controlled to determine the axial positions of the arms relative to the tool. Specifically, as the arm ends move, they are caused to rotate by a cam mechanism. The stiffness of the arms causes the arm ends to rotate in unison, and the exact positions of the arms on the tool are then controlled by the differential movements of the arm ends in the cams

  8. Drive mechanism nuclear reactor control rod

    International Nuclear Information System (INIS)

    Brooks, J.G. Jr.; Maure, D.R.; Meijer, C.H.

    1978-01-01

    An improved method and apparatus for operating magnetic stepping-type mechanisms. The current flowing in the coils of magnetic stepping-type mechanisms of the kind, for instance, that are used in control-element drive mechanisms is sensed and used to monitor operation of the mechanism. Current waveforms that characterize the motion of the mechanism are used to trigger changes in drive voltage and to verify that the drive mechanism is operating properly. In addition, incipient failures are detected through the observation of differences between the observed waveform and waveforms that characterize proper operation

  9. Influence of stability of polymer surfactant on oil displacement mechanism

    Science.gov (United States)

    Liu, Li; Li, Chengliang; Pi, Yanming; Wu, Di; He, Ying; Geng, Liang

    2018-02-01

    At present, most of the oilfields of China have entered the late stage of high water-cut development, and three oil recovery technique has become the leading technology for improving oil recovery. With the improvement of three oil recovery techniques, the polymer surfactant flooding technology has been widely promoted in oil fields in recent years. But in the actual field experiment, it has been found that the polymer surfactant has chromatographic separation at the extraction end, which indicates that the property of the polymer surfactant has changed during the displacement process. At present, there was few literature about how the stability of polymer surfactant affects the oil displacement mechanism. This paper used HuaDing-I polymer surfactant to conduct a micro photolithography glass flooding experiment, and then compared the oil displacement law of polymer surfactant before and after static setting. Finally, the influence law of stability of polymer surfactant on the oil displacement mechanism is obtained by comprehensive analysis.

  10. General mechanism for helium blistering involving displaced atom transport

    Energy Technology Data Exchange (ETDEWEB)

    McDonell, W.R.

    1979-01-01

    A mechanism developed to account for formation of vertically elongated blisters in high displacement environments produced by /sup 252/Cf alpha particles and fission fragments has been extended to formation of done-shaped blisters in the low displacement environments produced by simple helium ion beams. In this mechanism, transport of displaced atoms to relieve compressive stresses in the helium-implanted layer allows interconnections of small, subsurface bubbles to form the blister cavity. The same transport may cause thickening of the blister caps at low implantation energies. The transition from dome-shaped to vertically elongated blistering occurs between the 300 and 3000 displacements per helium atom produced by simple helium ions and /sup 252/Cf radiations respectively.

  11. Competition drives trait evolution and character displacement between Mimulus species along an environmental gradient.

    Science.gov (United States)

    Kooyers, Nicholas J; James, Brooke; Blackman, Benjamin K

    2017-05-01

    Closely related species may evolve to coexist stably in sympatry through niche differentiation driven by in situ competition, a process termed character displacement. Alternatively, past evolution in allopatry may have already sufficiently reduced niche overlap to permit establishment in sympatry, a process called ecological sorting. The relative importance of each process to niche differentiation is contentious even though they are not mutually exclusive and are both mediated via multivariate trait evolution. We explore how competition has impacted niche differentiation in two monkeyflowers, Mimulus alsinoides and M. guttatus, which often co-occur. Through field observations, common gardens, and competition experiments, we demonstrate that M. alsinoides is restricted to marginal habitats in sympatry and that the impacts of character displacement on niche differentiation are complex. Competition with M. guttatus alters selection gradients and has favored taller M. alsinoides with earlier seasonal flowering at low elevation and floral shape divergence at high elevation. However, no trait exhibits the pattern typically associated with character displacement, higher divergence between species in sympatry than allopatry. Thus, although character displacement was unlikely the process driving initial divergence along niche axes necessary for coexistence, we conclude that competition in sympatry has likely driven trait evolution along additional niche axes. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  12. Blow molding electric drives of Mechanical Engineering

    Science.gov (United States)

    Bukhanov, S. S.; Ramazanov, M. A.; Tsirkunenko, A. T.

    2018-03-01

    The article considers the questions about the analysis of new possibilities, which gives the use of adjustable electric drives for blowing mechanisms of plastic production. Thus, the use of new semiconductor converters makes it possible not only to compensate the instability of the supply network by using special dynamic voltage regulators, but to improve (correct) the power factor. The calculation of economic efficiency in controlled electric drives of blowing mechanisms is given. On the basis of statistical analysis, the calculation of the reliability parameters of the regulated electric drives’ elements under consideration is given. It is shown that an increase in the reliability of adjustable electric drives is possible both due to overestimation of the electric drive’s installed power, and in simpler schemes with pulse-vector control.

  13. Displacement effects of pile driving during offshore wind farm construction on harbour porpoises (Phocoena Phocoena)

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Miriam; Diederichs, Ansgar; Wollheim, Laura; Betke, Klaus; Nehls, Georg

    2011-07-01

    Full text: Noise emissions from pile driving during offshore wind farm construction may injure marine mammals in the vicinity and cause large-scale disturbance and habitat displacement. So far little is known about the responses of marine mammals to such noise emissions making it difficult to predict possible impacts on their population and conservation status. We investigated spatial and temporal responses of harbour porpoises to pile driving during construction of 92 mono-pile foundations in the Danish North Sea in 2008 and of 6 tripod and 6 jacket foundations in the German North Sea in 2009. We used passive acoustic monitoring devices that record harbour porpoise echolocation clicks (T-PODs), which were deployed at different distances from the construction site. Noise levels during pile driving were measured at various distances. We found a clear impact of pile driving on the recordings of harbour porpoises, which stayed below average normal levels for up to 72 hours after pile driving in the near vicinity. A negative impact could be detected out to a distance of about 18 km, while at 22 km no negative effect was found. Here porpoise recordings temporarily increased. This shows that effects of wind farm construction reach over considerable distances and last much longer than previously assumed. We further found some differences between the effects of the different types of construction, possibly linked to the varying pile driving durations that were necessary. These results should be considered for future spatial and temporal planning of offshore wind farm constructions. Suitable mitigation measures should be adopted to reduce such far and long reaching effects on harbour porpoises and possibly other marine mammals. (Author)

  14. Mechanism of chimera formation during the Multiple Displacement Amplification reaction

    Directory of Open Access Journals (Sweden)

    Stockwell Timothy B

    2007-04-01

    Full Text Available Abstract Background Multiple Displacement Amplification (MDA is a method used for amplifying limiting DNA sources. The high molecular weight amplified DNA is ideal for DNA library construction. While this has enabled genomic sequencing from one or a few cells of unculturable microorganisms, the process is complicated by the tendency of MDA to generate chimeric DNA rearrangements in the amplified DNA. Determining the source of the DNA rearrangements would be an important step towards reducing or eliminating them. Results Here, we characterize the major types of chimeras formed by carrying out an MDA whole genome amplification from a single E. coli cell and sequencing by the 454 Life Sciences method. Analysis of 475 chimeras revealed the predominant reaction mechanisms that create the DNA rearrangements. The highly branched DNA synthesized in MDA can assume many alternative secondary structures. DNA strands extended on an initial template can be displaced becoming available to prime on a second template creating the chimeras. Evidence supports a model in which branch migration can displace 3'-ends freeing them to prime on the new templates. More than 85% of the resulting DNA rearrangements were inverted sequences with intervening deletions that the model predicts. Intramolecular rearrangements were favored, with displaced 3'-ends reannealing to single stranded 5'-strands contained within the same branched DNA molecule. In over 70% of the chimeric junctions, the 3' termini had initiated priming at complimentary sequences of 2–21 nucleotides (nts in the new templates. Conclusion Formation of chimeras is an important limitation to the MDA method, particularly for whole genome sequencing. Identification of the mechanism for chimera formation provides new insight into the MDA reaction and suggests methods to reduce chimeras. The 454 sequencing approach used here will provide a rapid method to assess the utility of reaction modifications.

  15. Motion laws synthesis for cam mechanisms with multiple follower displacement

    Science.gov (United States)

    Podgornyj, Yu I.; Skeeba, V. Yu; Kirillov, A. V.; Martynova, T. G.; Skeeba, P. Yu

    2018-03-01

    The research discusses the cam mechanisms design. The analysis of specialized literature indicates that the synthesis of the cam mechanisms laws of motion is currently done mainly by a standard set of acceleration curves. In some cases, the designer needs to synthesize a new acceleration law which should be task-specific and enforce a certain production step. The values of the technological loads and inertia forces loads generated by the mechanism are calculated to analyze the slay mechanism behavior in the production of closely woven fabrics. Mathematical packages MathCad and SolidWorks are used in calculations. As a result of the research, the authors propose the methodology for synthesizing the slay mechanism with multiple follower displacements for the point of contact between the reed and the fabric edge. Theoretical studies have been tested on a specific machine model (STB loom). The authors have synthesized the motion law of the filling threads beat-up mechanism for the production of strong fabrics. New basic and closing cam profiles are proposed. The results are designed to enhance the possibilities of the looms and to recommend the most efficient equipment operation modes for the producers.

  16. Maintenance of BWR control rod drive mechanisms

    International Nuclear Information System (INIS)

    Greene, R.H.

    1991-01-01

    Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper

  17. A thermodynamic approach to compare the performance of rhombic-drive and crank-drive mechanisms for a beta-type Stirling engine

    International Nuclear Information System (INIS)

    Aksoy, F.; Solmaz, H.; Karabulut, H.; Cinar, C.; Ozgoren, Y.O.; Polat, Seyfi

    2016-01-01

    Highlights: • Rhombic drive and crank drive mechanisms of a beta type engine were compared. • Nodal analysis method was used to compare engines having different drive mechanism. • Maximum specific power was 1410 W/L for rhombic-drive engine. • Heat transfer coefficient was determined as 475 W/m 2 K for rhombic-drive engine. • Rhombic drive provided higher efficiency because of its better kinematic behaviours. - Abstract: In this study, the effect of rhombic drive and crank drive mechanisms on the performance of a beta-type Stirling engine was investigated by nodal analysis. Kinematic and thermodynamic relations for both drive mechanisms were introduced and a Fortran code was written for the solution. Piston strokes, cylinder and displacer diameters, hot and cold end temperatures, regenerator volumes and heat transfer surface areas were taken equal for both engines with two different drive mechanisms. In the analysis, air was used as the working gas. Engine power and efficiency were compared for different charge pressure values, working gas mass values, heat transfer coefficients and hot end temperatures. Maximum specific engine power was 1410 W/L for the engine with rhombic drive mechanism and 1200 W/L for the engine with crank drive mechanism at 4 bars of charge pressure and 500 W/m 2 K heat transfer coefficient. Rhombic drive mechanism was relatively advantageous at low working gas mass values and high hot end temperatures. In comparison with the engine having rhombic drive mechanism, the relatively poor kinematic behaviour of the engine having crank drive mechanism caused lower engine efficiency and performance. Heat transfer coefficient was also predicted by using an experimental pressure trace.

  18. Physical Mechanisms Driving Cell Sorting in Hydra.

    Science.gov (United States)

    Cochet-Escartin, Olivier; Locke, Tiffany T; Shi, Winnie H; Steele, Robert E; Collins, Eva-Maria S

    2017-12-19

    Cell sorting, whereby a heterogeneous cell mixture organizes into distinct tissues, is a fundamental patterning process in development. Hydra is a powerful model system for carrying out studies of cell sorting in three dimensions, because of its unique ability to regenerate after complete dissociation into individual cells. The physicists Alfred Gierer and Hans Meinhardt recognized Hydra's self-organizing properties more than 40 years ago. However, what drives cell sorting during regeneration of Hydra from cell aggregates is still debated. Differential motility and differential adhesion have been proposed as driving mechanisms, but the available experimental data are insufficient to distinguish between these two. Here, we answer this longstanding question by using transgenic Hydra expressing fluorescent proteins and a multiscale experimental and numerical approach. By quantifying the kinematics of single cell and whole aggregate behaviors, we show that no differences in cell motility exist among cell types and that sorting dynamics follow a power law with an exponent of ∼0.5. Additionally, we measure the physical properties of separated tissues and quantify their viscosities and surface tensions. Based on our experimental results and numerical simulations, we conclude that tissue interfacial tensions are sufficient to explain cell sorting in aggregates of Hydra cells. Furthermore, we demonstrate that the aggregate's geometry during sorting is key to understanding the sorting dynamics and explains the exponent of the power law behavior. Our results answer the long standing question of the physical mechanisms driving cell sorting in Hydra cell aggregates. In addition, they demonstrate how powerful this organism is for biophysical studies of self-organization and pattern formation. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  19. Research on the porous flow of the mechanism of viscous-elastic fluids displacing residual oil droplets in micro pores

    Science.gov (United States)

    Dong, Guanyu

    2018-03-01

    In order to analyze the microscopic stress field acting on residual oil droplets in micro pores, calculate its deformation, and explore the hydrodynamic mechanism of viscous-elastic fluids displacing oil droplets, the viscous-elastic fluid flow equations in micro pores are established by choosing the Upper Convected Maxwell constitutive equation; the numerical solutions of the flow field are obtained by volume control and Alternate Direction Implicit methods. From the above, the velocity field and microscopic stress field; the forces acting on residual oil droplets; the deformations of residual oil droplets by various viscous-elastic displacing fluids and at various Wiesenberg numbers are calculated and analyzed. The result demonstrated that both the normal stress and horizontal force acting on the residual oil droplets by viscous-elastic fluids are much larger compared to that of inelastic fluid; the distribution of normal stress changes abruptly; under the condition of the same pressure gradient in the system under investigation, the ratio of the horizontal forces acting on the residual oil droplets by different displacing fluids is about 1:8:20, which means that under the above conditions, the driving force on a oil droplet is 20 times higher for a viscous-elastic fluid compared to that of a Newtonian Fluid. The conclusions are supportive of the mechanism that viscous-elastic driving fluids can increase the Displacement Efficiency. This should be of help in designing new chemicals and selecting Enhanced Oil Recovery systems.

  20. Design of the pulse rod drive mechanism for pulsed reactor

    International Nuclear Information System (INIS)

    You Keyi

    1988-07-01

    The pulse rod drive mechanism is a critical movable device for a pulsed reactor. It is an executor under pulse operations, and it may be used in a shim rod under steady-state operations. The pneumatic-electromechanical driving method is taken in the designing. The structure, operating, calculation of parameters and designing methods of the pulse rod drive mechanism are briefly described in this paper. The testing results of the prototypical mechanism are also presented

  1. Do environmental changes or juvenile competition act as mechanisms of species displacement in crayfishes?

    Science.gov (United States)

    Westhoff, Jacob T.; DiStefano, R.J.; Magoulick, D.D.

    2012-01-01

    The Big Creek Crayfish, Orconectes peruncus, is native to the St. Francis River drainage in Missouri, USA and is often absent where the introduced Woodland Crayfish, Orconectes hylas, has established. We performed a field experiment to determine whether effects of current abiotic conditions and interspecific competition with O. hylas were responsible for displacement of O. peruncus from parts of their former range. We examined growth and survival of juvenile male O. peruncus exposed to juvenile male O. hylas in enclosures at two sites in the former range of O. peruncus. Enclosures contained 8 (low density) or 16 individuals (high density) and had O. peruncus only (control) or both species (interspecific treatment). Juvenile O. peruncus were able to survive and grow in portions of their former range, implicating biotic versus abiotic factors in the displacement of O. peruncus. Survival rates of O. peruncus did not differ among treatments at either site. Orconectes peruncus showed significant growth in all treatments and interspecific effects were not greater than intraspecific effects on O. peruncus growth rates. High-density treatments showed significantly reduced O. peruncus growth rates compared to low-density treatments, except in Carver Creek interspecific treatments. When considered in the context of previous studies examining the effects of O. hylas on O. peruncus, results suggest that neither direct competition between juvenile males of the two species or abiotic change are responsible for the decreased range of O. peruncus. Additional research is required to determine the mechanism(s) driving the displacement of O. peruncus. ?? 2011 Springer Science+Business Media B.V.

  2. Static Analysis of High-Performance Fixed Fluid Power Drive with a Single Positive-Displacement Hydraulic Motor

    Directory of Open Access Journals (Sweden)

    O. F. Nikitin

    2015-01-01

    Full Text Available The article deals with the static calculations in designing a high-performance fixed fluid power drive with a single positive-displacement hydraulic motor. Designing is aimed at using a drive that is under development and yet unavailable to find and record the minimum of calculations and maximum of existing hydraulic units that enable clear and unambiguous performance, taking into consideration an available assortment of hydraulic units of hydraulic drives, to have the best efficiency.The specified power (power, moment and kinematics (linear velocity or angular velocity of rotation parameters of the output element of hydraulic motor determine the main output parameters of the hydraulic drive and the useful power of the hydraulic drive under development. The value of the overall efficiency of the hydraulic drive enables us to judge the efficiency of high-performance fixed fluid power drive.The energy analysis of a diagram of the high-performance fixed fluid power drive shows that its high efficiency is achieved when the flow rate of fluid flowing into each cylinder and the magnitude of the feed pump unit (pump are as nearly as possible.The paper considers the ways of determining the geometric parameters of working hydromotors (effective working area or working volume, which allow a selection of the pumping unit parameters. It discusses the ways to improve hydraulic drive efficiency. Using the principle of holding constant conductivity allows us to specify the values of the pressure losses in the hydraulic units used in noncatalog modes. In case of no exact matching between the parameters of existing hydraulic power modes and a proposed characteristics of the pump unit, the nearest to the expected characteristics is taken as a working version.All of the steps allow us to create the high-performance fixed fluid power drive capable of operating at the required power and kinematic parameters with high efficiency.

  3. Mechanisms of Social Movement Success: Conversation, Displacement and Disruption

    Directory of Open Access Journals (Sweden)

    Fishman, Robert M.

    2016-12-01

    Full Text Available A great deal of social movement scholarship tends to assume – and in some cases explicitly argues – that disruption is the primary mechanism through which protest movements win major concessions from the holders of power. Nonetheless, some studies and much empirical evidence provide a strong basis to argue that other paths to social movement success also exist. The importance of discourse and framing has also been highlighted in a number of studies but we argue that the full contribution of talk itself to movement success is best captured through the concept of “conversation” and an examination of the preconditions for its viability. The successful displacement of power-holders by protest movements, although a less common pathway to success than disruption and conversation, also deserves conceptual and empirical attention. In this paper we make this set of distinctions conceptually explicit, differentiating analytically between these three mechanisms of movement success and delineating the conditions required for each mechanism to prove viable and ‘useful’. We rely on extensive examples drawn from movements and protest events in the United States, Spain and Portugal, using this empirical material, as well as the existing theoretical literature, as our basis for constructing a conceptual argument on the ideal typical distinction between these three mechanisms and the conditions that allow them to operate. We also take up the questions of whether, and when, movement actors can successfully combine these mechanisms or – alternatively – find themselves pressed to pursue one or another of these pathways to success in a relatively ‘pure’ form.Buena parte de la investigación en movimientos sociales tiende a asumir - y en algunos casos argumenta de manera explícita - que la disrupción es el principal mecanismo a través del cual los movimientos de protesta obtienen importantes concesiones por parte de quienes detentan el poder. No

  4. Method of inspecting control rod drive mechanism

    International Nuclear Information System (INIS)

    Sato, Tomomi; Tatemichi, Shin-ichiro; Hasegawa, Hidenobu.

    1988-01-01

    Purpose: To conduct inspection for control rod drives and fuel handling operations in parallel without taking out the entire fuel, while maintaining the reactor in a subcritical state. Method: Control rod drives are inspected through the release of connection between control rods and control rod drives, detachment and dismantling of control rod drives, etc. In this case, structural materials having neutron absorbing power equal to or greater than the control rods are inserted into the gap after taking out fuels. Since the structural materials have neutron absorbing portion, subcriticality is maintained by the neutron absorbing effect. Accordingly, there is no requirement for taking out all of the fuels, thereby enabling to check the control rod drives and conduct handling for the fuels in parallel. As a result, the number of days required for the inspection can be shortened and it is possible to improve the working efficiency for the decomposition, inspection, etc. of the control rod drives and, thus, improve the operation efficiency of the nuclear power plant thereby attaining the predetermined purpose. (Kawakami, Y.)

  5. Generating Sub-nanometer Displacement Using Reduction Mechanism Consisting of Torsional Leaf Spring Hinges

    Directory of Open Access Journals (Sweden)

    Fukuda Makoto

    2014-02-01

    Full Text Available Recent demand on the measurement resolution of precise positioning comes up to tens of picometers. Some distinguished researches have been performed to measure the displacement in picometer order, however, few of them can verify the measurement performance as available tools in industry. This is not only because the picometer displacement is not yet required for industrial use, but also due to the lack of standard tools to verify such precise displacement. We proposed a displacement reduction mechanism for generating precise displacement using torsional leaf spring hinges (TLSHs that consist of four leaf springs arranged radially. It has been demonstrated that a prototype of the reduction mechanism was able to provide one-nanometer displacement with 1/1000 reduction rate by a piezoelectric actuator. In order to clarify the potential of the reduction mechanism, a displacement reduction table that can be mounted on AFM stage was newly developed using TLSHs. This paper describes the design of the reduction mechanism and the sub-nanometer displacement performance of the table obtained from its dynamic and static characteristics measured by displacement sensors and from the AFM images

  6. Investigation of New Servo Drive Concept Utilizing Two Fixed Displacement Units

    DEFF Research Database (Denmark)

    Pedersen, Henrik Clemmensen; Schmidt, Lasse; Andersen, Torben O.

    2015-01-01

    Traditional valve controlled hydraulic drives have an inherent power loss, due to the throttling over the valves, which limits the maximum system efficiency. Pump controlled direct drives do not have this inherent limitation, but are limited when it comes to controlling asymmetric cylinders, why ...

  7. Competition and predation as mechanisms for displacement of greenback cutthroat trout by brook trout

    Science.gov (United States)

    C. C. McGrath; W. M. Lewis

    2007-01-01

    Cutthroat trout Oncorhynchus clarkii frequently are displaced by nonnative brook trout Salvelinus fontinalis, but the ecological mechanisms of displacement are not understood. Competition for food and predation between greenback cutthroat trout O. c. stomias and brook trout were investigated in montane streams of...

  8. A linear chromatic mechanism drives the pupillary response.

    Science.gov (United States)

    Tsujimura, S; Wolffsohn, J S; Gilmartin, B

    2001-11-07

    Previous studies have shown that a chromatic mechanism can drive pupil responses. The aim of this research was to clarify whether a linear or nonlinear chromatic mechanism drives pupillary responses by using test stimuli of various colours that are defined in cone contrast space. The pupil and accommodation responses evoked by these test stimuli were continuously and simultaneously objectively measured by photorefraction. The results with isochromatic and isoluminant stimuli showed that the accommodative level remained approximately constant (linear chromatic mechanism, whereby a signal from the long wavelength cone is subtracted from that of the middle wavelength cone and vice versa, drives pupillary responses.

  9. Cam Drive Step Mechanism of a Quadruped Robot

    Directory of Open Access Journals (Sweden)

    Qun Sun

    2014-01-01

    Full Text Available Bionic quadruped robots received considerable worldwide research attention. For a quadruped robot walking with steady paces on a flat terrain, using a cam drive control mechanism instead of servomotors provides theoretical and practical benefits as it reduces the system weight, cost, and control complexities; thus it may be more cost beneficial for some recreational or household applications. This study explores the robot step mechanism including the leg and cam drive control systems based on studying the bone structure and the kinematic step sequences of dog. The design requirements for the cam drive robot legs have been raised, and the mechanical principles of the leg operating mechanism as well as the control parameters have been analyzed. A cam drive control system was constructed using three cams to control each leg. Finally, a four-leg demo robot was manufactured for experiments and it showed stable walking patterns on a flat floor.

  10. Normal temperature ventilating homogenity test of control rod drive mechanism

    International Nuclear Information System (INIS)

    Zhu Longxing.

    1987-01-01

    This paper describes the cooling for the control rod drive mechanism. It emphatically introduces some problems which must be considered in the test on ventilating homogenity under normal temperature for the control rod drive mechanism at the top of a reactor such as the selection of cooling shroud assemblies, installed position of ducts, volume of the static pressure container, etc. The test data of blowing-in and induced draft are compared and analysed

  11. Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems

    Directory of Open Access Journals (Sweden)

    Xavier Arouette

    2010-03-01

    Full Text Available We have developed a hydraulic displacement amplification mechanism (HDAM and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.

  12. Multi-function magnetic jack control drive mechanism

    International Nuclear Information System (INIS)

    Bollinger, L.R.; Crawford, D.C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism is described for controlling a nuclear reactor comprising: an elongate pressure housing; closely-spaced drive rods located in the pressure housing, the drive rod being connected to a reactor rod which is insertable in a reactor core; electrochemical stationary latch means which are selectively actuatable for holding a respective one of the drive rods stationary with respect to the pressure housing, the plurality of stationary latch means including at least one coil located about the pressure housing; longitudinally spaced electromechanical movable latch means, individually associated with one of the drive rods and each including a base for the drive rod associated therewith, for, when actuated, holding the associated drive rod stationary with respect to the base associated therewith, the movable latch means including an associated coil located about the pressure housing; and longitudinally spaced electromechanical lift means, individually associated with the base, for, when actuated, moving an associated base longitudinally along the pressure housing from a first position to a second position to thereby enable movement of one or more of the other drive rods longitudinally independently of the other drive rods in response to sequential and repeated operation of the electromechanical means, the lift means including an associated coil located about the pressure housing

  13. Driving Force Filtering and Driving Mechanism Analysis of Urban Agricultural Development in Weifang County, China

    Directory of Open Access Journals (Sweden)

    SUI Fei-fei

    2016-03-01

    Full Text Available As an agricultural nation, the agricultural landscape is the basic appearance and existence in China, but the common existence often be neglected and contempted. As a new type of design and ideology, the development of urban agricultural landscape will greatly affect the texture and structure of the urban space. According to the urban agricultural production data and the socio-economic data of Weifang County, a set of evaluation index system that could analyze quantitatively the driving force of urban agricultural production changes and the internal drive mechanism was built. The original driving force indicators of economy, society, resources and environment from the time-series were chosen, and then 15 driving forces from the original driving forces by correlation analysis and principal component analysis were selected. The degree of influence was analyzed and the driving forces model by means of partial least squares(PLS was built. The results demonstrated that the factors greatly influenced the increase of urban agricultural output value in Weifang County were per capita net income of rural residents, agricultural machinery total power, effective irrigation area, centralized treatment rate of urban sewage, with the driving exponents 0.2509, 0.1019, 0.1655, 0.1332, respectively. The negative influence factor was the use amount of agricultural plastic film and the driving exponent was-0.2146. The research provides a reference for the development of urban agriculture, as well as a reference for the related study.

  14. Contact-type displacement measuring mechanism for fuel assembly in reactor

    International Nuclear Information System (INIS)

    Yokota, Yoshio; Ko, Kuniaki.

    1995-01-01

    The measuring mechanism of the present invention, which is used in a lmfbr type reactor, is suspended by a gripper of a fuel handing machine, and it comprises a combination of a displacement amount measuring jig allowed to be inserted into a handling head of a fuel assembly and a displacement amount measuring ring disposed at the lower portion in the handling head. The displacement amount measuring jig has a structure comprising a releasable handle and a columnar or cylindrical measuring portion allowable to be inserted into the handling head formed at the lower portion of the handle, which are connected with each other. When an interference (contact) occurred between the displacement amount measuring jig and the stepwise displacement amount measuring ring during the measurement, change of load and a phenomenon that the fuel handing machine can not be lowered are recognized, so that core displacement amount can be recognized based on the stroke of the gripper portion. Then, remote measurement is possible for displacement and deformation of the fuel assembly in the reactor container, and the measurement can be conducted by the same procedures and in the same period of time as in a case of ordinary fuel exchange operation. A flow channel for coolants passing through the fuel assembly can be ensured, thereby enabling to measure the amount of core displacement which is closer to an actual value in the reactor. (N.H.)

  15. A comparison of drive mechanisms for precision motion controlled stages

    Energy Technology Data Exchange (ETDEWEB)

    Buice, E S; Yang, H; Otten, D; Smith, S T; Hocken, R J; Trumper, D L; Seugling, R M

    2006-03-22

    This abstract presents a comparison of two drive mechanisms, a Rohlix{reg_sign} drive and a polymer nut drive, for precision motion controlled stages. A single-axis long-range stage with a 50 mm traverse combined with a short-range stage with a 16 {micro}m traverse at a operational bandwidth of 2.2 kHz were developed to evaluate the performance of the drives. The polymer nut and Rohlix{reg_sign} drives showed 4 nm RMS and 7 nm RMS positioning capabilities respectively, with traverses of 5 mm at a maximum velocity of 0.15 mm{sup -}s{sup -1} with the short range stage operating at a 2.2 kHz bandwidth. Further results will be presented in the subsequent sections.

  16. Improvements in or relating to rotary drive mechanisms

    International Nuclear Information System (INIS)

    Lodge, J.A.

    1981-01-01

    The invention relates to rotary drive mechanisms and relates especially, though not exclusively, to such mechanisms for use in rotating a source of penetrating radiation, such as X-radiation, in steps around a body, in the course of a computerised tomographic (CAT) examination of the body. (author)

  17. Robust design of large-displacement compliant mechanisms

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Schevenels, M.; Sigmund, Ole

    2011-01-01

    The aim of this article is to introduce a new topology optimisation formulation for optimal robust design of Micro Electro Mechanical Systems. Mesh independence in topology optimisation is most often ensured by using filtering techniques, which result in transition grey regions difficult...... in nearly black and white mechanism designs, robust with respect to uncertainties in the production process, i.e. without any hinges or small details which can create manufacturing difficulties....... to interpret in practical realisations. This problem has been alleviated recently by projection techniques, but these destroy the mesh independence introduced by the filters and result in single node connected hinges. Such features in the design are undesirable as they are not robust with respect to geometric...

  18. Multiple evolutionary mechanisms drive papillomavirus diversification.

    Science.gov (United States)

    Gottschling, Marc; Stamatakis, Alexandros; Nindl, Ingo; Stockfleth, Eggert; Alonso, Angel; Bravo, Ignacio G

    2007-05-01

    The circular, double-stranded 8-kb DNA genome of papillomaviruses (PVes) consists mainly of 4 large genes, E1, E2, L2, and L1. Approximately 150 papillomavirus genomes have been sequenced to date. We analyzed a representative sample of 53 PVes genomes using maximum likelihood, Bayesian inference, maximum parsimony, and distance-based methods both on nucleotide (nt) and on amino acid (aa) alignments. When the 4 genes were analyzed separately, aa-inferred phylogenies contradicted each other less than nt-inferred trees (judged by partition homogeneity tests). In particular, gene combinations including the L2 gene generated significant incongruence (P artifacts and insufficient taxon sampling, may contribute to the incomplete resolution of deep phylogenetic nodes. The molecular data globally supports a complex evolutionary scenario for PVes, which is driven by multiple mechanisms but not exclusively by coevolution with corresponding hosts.

  19. Design and Analysis of a Novel Articulated Drive Mechanism for Multifunctional NOTES Robot.

    Science.gov (United States)

    Shen, Tao; Nelson, Carl A; Warburton, Kevin; Oleynikov, Dmitry

    2015-02-01

    This paper presents a novel articulated drive mechanism (ADM) for a multifunctional natural orifice transluminal endoscopic surgery (NOTES) robotic manipulator. It consists mainly of three major components including a snakelike linkage, motor housing, and an arm connector. The ADM can articulate into complex shapes for improved access to surgical targets. A connector provides an efficient and convenient modularity for insertion and removal of the robot. Four DC motors guide eight cables to steer the robot. The workspace, cable displacement and force transmission relationships are derived. Experimental results give preliminary validation of the feasibility and capability of the ADM system.

  20. Novel Spherical Robot with Hybrid Pendulum Driving Mechanism

    Directory of Open Access Journals (Sweden)

    Sung-Su Ahn

    2014-11-01

    Full Text Available As regards omnidirectional driving, conventional one- and two-pendulum spherical robots have a limited capability due to a limited pendulum motion range. In particular, such robots cannot move from a stationary state in a parallel direction to the center horizontal axis to which the pendulums are attached. Thus, to overcome the limited driving capability of one- and two-pendulum driven spherical robots, a passive version of a spherical robot, called KisBot II, was developed with a curved two-pendulum driving mechanism operated by a joystick. However, this paper presents an active upgraded version of KisBot II that includes a DSP-based control system and Task-based software architecture for driving control and data communication, respectively. A dynamic model for two-pendulum driving is derived using the Lagrange equation method, and a feedback controller for linear driving using two pendulums is then constructed based on the dynamic model. Experiments with several motions verify the driving efficiency of the proposed novel spherical robot.

  1. Control rod drive mechanism with shock absorber for nuclear reactor

    International Nuclear Information System (INIS)

    Chevereau, G.

    1989-01-01

    The mechanism usable in a PWR has a shaft carrying the bar vertically displaceable in the reactor internals and a dash pot with a hydraulic cylinder and a piston. The cylinder has a large diameter perforated upper section to the cylinder, a small diameter lower section, a piston traversed by the control rod sized to fit into the upper section and forced downwards when the control descends. The shock absorbing chamber is defined between the piston and the upper section [fr

  2. Enhanced Oil Recovery Using Micron-Size Polyacrylamide Elastic Microspheres (MPEMs): Underlying Mechanisms and Displacement Experiments

    KAUST Repository

    Yao, Chuanjin

    2015-10-12

    Micron-size polyacrylamide elastic microsphere (MPEM) is a newly developed profile control and oil displacement agent for enhanced oil recovery in heterogeneous reservoirs. In this study, laboratory experiments were performed to characterize the viscoelastic properties of MPEMs in brine water. A transparent sandpack micromodel was used to observe the microscopic flow and displacement mechanisms, and parallel-sandpack models were used to investigate the profile control and oil displacement performance using MPEMs in heterogeneous reservoirs. The results indicate that MPEMs almost do not increase the viscosity of injection water and can be conveniently injected using the original water injection pipelines. The microscopic profile control and oil displacement mechanisms of MPEMs in porous media mainly behave as selective-plugging in large pores, fluid diversion after MPEMs plugging, oil drainage caused by MPEMs breakthrough, and the mechanism of oil droplets converging into oil flow. MPEMs have a high plugging strength, which can tolerate a long-term water flushing. MPEMs can selectively enter and plug the large pores and pore-throats in high permeability sandpack, but almost do not damage the low permeability sandpack. MPEMs can effectively divert the water flow from the high permeability sandpack to the low permeability sandpack and improve the sweep efficiency of low permeability sandpack and low permeability area in the high permeability sandpack. The results also confirm the dynamic process of profile control and oil displacement using MPEMs in heterogeneous reservoirs.

  3. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    Directory of Open Access Journals (Sweden)

    A. I. Safonov

    2009-01-01

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

  4. Electromagnetic design calculation of the control rod drive mechanism

    International Nuclear Information System (INIS)

    Zhu Qirong; Zhu Jingchang

    1991-01-01

    Electromagnetic design calculation of the step-by-step magnetic jacking control rod drive mechanism includes magnetic field force calculation and design calculation of magnetomotive force for three electromagnetic iron and their coilds. The basic principle and method of electromagnetic design calculation had been expounded to take the lift magnet and lift coil for example

  5. Arcsecond grating drive mechanism for operation at 4 K

    Science.gov (United States)

    Downey, C. H.; Kubitschek, M. J.; Tarde, R. W.; Houck, J. R.

    1991-12-01

    A grating drive mechanism that achieves arcsecond positional control at both room temperature and 4 K is described. The mechanism accommodates eight equally spaced facets on a 360-deg drum, with each facet having arcsecond control over an angular range of +/-3 deg. The cryogenic portion consists of dry lubricated angular contact bearings, a dc brushless torque motor, and a compact magnetic position sensor capable of less than 1 arcsec rms resolution. Test results demonstrate angular repeatability of less than 2 arcsec rms at 4 K and static power dissipation to the helium bath of less than 100 microW.

  6. Exact solution for stresses/displacements in a multilayered hollow cylinder under thermo-mechanical loading

    International Nuclear Information System (INIS)

    Yeo, W.H.; Purbolaksono, J.; Aliabadi, M.H.; Ramesh, S.; Liew, H.L.

    2017-01-01

    In this study, a new analytical solution by the recursive method for evaluating stresses/displacements in multilayered hollow cylinder under thermo-mechanical loading was developed. The results for temperature distribution, displacements and stresses obtained by using the proposed solution were shown to be in good agreement with the FEM results. The proposed analytical solution was also found to produce more accurate results than those by the analytical solution reported in literature. - Highlights: • A new analytical solution for evaluating stresses in multilayered hollow cylinder under thermo-mechanical loading. • A simple computational procedure using a recursive method. • A promising technique for evaluating the operating axial and hoop stresses in pressurized composite vessels.

  7. PWM Carrier Displacement in Multi-N-Phase Drives: An Additional Degree of Freedom to Reduce the DC-Link Stress

    Directory of Open Access Journals (Sweden)

    Michela Diana

    2018-02-01

    Full Text Available The paper presents a particular Pulse Width Modulation (PWM strategy to reduce the (Direct Current DC-link capacitor stress for multi-n-phase drives. A multi-n-phase drive is composed of multiple independent systems of n inverter supplying a multi-n-phase electric machine. The paper focused on the investigation of the best phase shifting between carriers for a triple-3-phase drive compared to the 3-phase counterpart in order to reduce the capacitor bench design point. Simulation and experimental results show as the control technique proposed is able to reduce the value of the DC-link capacitor current in any operating condition including fault case. In this sense, the PWM carrier displacement appears like an additional degree of freedom that can be exploited in multi-n-phase drives but also in multi-motor application.

  8. Label-free histamine detection with nanofluidic diodes through metal ion displacement mechanism

    OpenAIRE

    Ali, Mubarak; Ramirez Hoyos, Patricio; Duznovic, Ivana; Nasir, Saima; Mafe, Salvador; Ensinger, Wolfgang

    2017-01-01

    [EN] We design and characterize a nanofluidic device for the label-free specific detection of histamine neurotransmitter based on a metal ion displacement mechanism. The sensor consists of an asymmetric polymer nanopore fabricated via ion track-etching technique. The nanopore sensor surface having metal-nitrilotriacetic (NTA-Ni2+) chelates is obtained by covalent coupling of native carboxylic acid groups with N-alpha,N-alpha-bis(carboxymethyl)-L-lysine (BCML), followed by exposure to Ni2+ ion...

  9. Shell Tectonics: A Mechanical Model for Strike-slip Displacement on Europa

    Science.gov (United States)

    Rhoden, Alyssa Rose; Wurman, Gilead; Huff, Eric M.; Manga, Michael; Hurford, Terry A.

    2012-01-01

    We introduce a new mechanical model for producing tidally-driven strike-slip displacement along preexisting faults on Europa, which we call shell tectonics. This model differs from previous models of strike-slip on icy satellites by incorporating a Coulomb failure criterion, approximating a viscoelastic rheology, determining the slip direction based on the gradient of the tidal shear stress rather than its sign, and quantitatively determining the net offset over many orbits. This model allows us to predict the direction of net displacement along faults and determine relative accumulation rate of displacement. To test the shell tectonics model, we generate global predictions of slip direction and compare them with the observed global pattern of strike-slip displacement on Europa in which left-lateral faults dominate far north of the equator, right-lateral faults dominate in the far south, and near-equatorial regions display a mixture of both types of faults. The shell tectonics model reproduces this global pattern. Incorporating a small obliquity into calculations of tidal stresses, which are used as inputs to the shell tectonics model, can also explain regional differences in strike-slip fault populations. We also discuss implications for fault azimuths, fault depth, and Europa's tectonic history.

  10. A calibration mechanism based on worm drive for space telescope

    Science.gov (United States)

    Chong, Yaqin; Li, Chuang; Xia, Siyu; Zhong, Peifeng; Lei, Wang

    2017-08-01

    In this paper, a new type of calibration mechanism based on worm drive is presented for a space telescope. This calibration mechanism based on worm drive has the advantages of compact size and self-lock. The mechanism mainly consists of thirty-six LEDs as the light source for flat calibration, a diffuse plate, a step motor, a worm gear reducer and a potentiometer. As the main part of the diffuse plate, a PTFE tablet is mounted in an aluminum alloy frame. The frame is fixed on the shaft of the worm gear, which is driven by the step motor through the worm. The shaft of the potentiometer is connected to that of the worm gear to measure the rotation angle of the diffuse plate through a flexible coupler. Firstly, the calibration mechanism is designed, which includes the LEDs assembly design, the worm gear reducer design and the diffuse plate assembly design. The counterweight blocks and two end stops are also designed for the diffuse plate assembly. Then a modal analysis with finite element method for the diffuse plate assembly is completed.

  11. Force Displacement Model of Compliant Mechanisms Using Assur Sub-Chains

    DEFF Research Database (Denmark)

    Durango, Sebastian; Correa, Jorge; Aristizabal, Mauricio

    2011-01-01

    This article develops a modular procedure to perform force-displacement modeling of planar flexurebased Compliant Mechanisms (CMs). The procedure is mostly suitable for planar lumped CMs. To achieve the position analysis of CMs requires: (i) to implement the kinematic analysis as in the case...... of ordinary mechanisms, (ii) to solve the equilibrium problem by means of a static analysis and (iii) to model the flexures behavior through a deflection analysis. The novel contribution of this article relies on the fact that a division strategy of the CM into Assur sub-chains is implemented, so that any CM...

  12. Conceptual Design of Bottom-mounted Control Rod Drive Mechanism

    International Nuclear Information System (INIS)

    Lee, Jin Haeng; Kim, Sanghaun; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Dongmin; Kim, Jong In

    2013-01-01

    The arrangement of the BMCRDMs and irradiation holes in the core is therefore easier than that of the top-mounted CRDM. Hence, many foreign research reactors, such as JRR-3M, JMTR, OPAL, and CARR, have adopted the BMCRDM concept. The purpose of this paper is to introduce the basic design concept on the BMCRDM. The major differences of the CRDMs between HANARO and KJRR are compared, and the design features and individual system of the BMCRDM for the KJRR are described. The Control Rod Drive Mechanism (CRDM) is a device to regulate the reactor power by changing the position of a Control Absorber Rod (CAR) and to shut down the reactor by fully inserting the CAR into the core within a specified time. The Bottom-Mounted CRDM (BMCRDM) for the KiJang Research Reactor (KJRR) is a quite different design concept compared to the top-mounted CRDM such as HANARO and JRTR. The main drive mechanism of the BMCRDM is located in a Reactivity Control Mechanism (RCM) room under the reactor pool bottom, which makes the interference with equipment in the reactor pool reduced

  13. Speed Controlled Belt Conveyors: Drives and Mechanical Considerations

    Directory of Open Access Journals (Sweden)

    BEBIC, M. Z.

    2018-02-01

    Full Text Available The paper presents variable speed belt conveyor system where the reference speed is changed in order to achieve improved energy efficiency of operation. The recorded measurements show that belt tension varies within the same limits as under constant speed operation. These results introduce a new insight of the present state of the art in variable speed belt conveyor drives. The system is realized with remote control from the control center on an open pit mine. The structure of the multi-motor drive system of a single conveyor, as well as of the network-based control system distributed among belt conveyor stations and the control center are shown. Speed control of a belt conveyor system is organized to provide better utilization of the available material cross section on the belt and reduced electrical energy consumption of the drive. The experimental results obtained on the system prove that, under existing constraints, the applied algorithm has not introduced additional stress to the belt or mechanical assemblies during acceleration and deceleration processes, while providing higher energy efficiency of operation.

  14. The driving mechanism of roAp stars

    Energy Technology Data Exchange (ETDEWEB)

    Dupret, M-A [Observatoire de Paris, LESIA, CNRS UMR 8109, 5 place J. Janssen, 92195 Meudon (France); Theado, S; Noels, A [Institut d' Astrophysique et Geophysique, Universite de Liege (Belgium)], E-mail: MA.dupret@obspm.fr

    2008-10-15

    We analyse in detail the driving mechanism of roAp stars and present the theoretical instability strip predicted by our models with solar metallicity. A particular attention is given to the interpretation of the role played by the different eigenfunctions in the stabilization of the modes at the red edge of the instability strip. The gradient of temperature in the H{sub I} opacity bump appears to play a major role in this context. We also consider the particular and complex role played by the shape of the eigenfunctions (location of the nodes, ...)

  15. Control rod drive mechanism stator loss of coolant test

    International Nuclear Information System (INIS)

    Besel, L.; Ibatuan, R.

    1977-04-01

    This report documents the stator loss of coolant test conducted at HEDL on the lead unit Control Rod Drive Mechanism (CRDM) in February, 1977. The purpose of the test was to demonstrate scram capability of the CRDM with an uncooled stator and to obtain a time versus temperature curve of an uncooled stator under power. Brief descriptions of the test, hardware used, and results obtained are presented in the report. The test demonstrated that the CRDM could be successfully scrammed with no anomalies in both the two-phase and three-phase stator winding hold conditions after the respective equilibrium stator temperatures had been obtained with no stator coolant

  16. Label-free histamine detection with nanofluidic diodes through metal ion displacement mechanism.

    Science.gov (United States)

    Ali, Mubarak; Ramirez, Patricio; Duznovic, Ivana; Nasir, Saima; Mafe, Salvador; Ensinger, Wolfgang

    2017-02-01

    We design and characterize a nanofluidic device for the label-free specific detection of histamine neurotransmitter based on a metal ion displacement mechanism. The sensor consists of an asymmetric polymer nanopore fabricated via ion track-etching technique. The nanopore sensor surface having metal-nitrilotriacetic (NTA-Ni 2+ ) chelates is obtained by covalent coupling of native carboxylic acid groups with N α ,N α -bis(carboxymethyl)-l-lysine (BCML), followed by exposure to Ni 2+ ion solution. The BCML immobilization and subsequent Ni 2+ ion complexation with NTA moieties change the surface charge concentration, which has a significant impact on the current-voltage (I-V) curve after chemical modification of the nanopore. The sensing mechanism is based on the displacement of the metal ion from the NTA-Ni 2+ chelates. When the modified pore is exposed to histamine solution, the Ni 2+ ion in NTA-Ni 2+ chelate recognizes histamine through a metal ion coordination displacement process and formation of stable Ni-histamine complexes, leading to the regeneration of metal-free NTA groups on the pore surface, as shown in the current-voltage characteristics. Nanomolar concentrations of the histamine in the working electrolyte can be detected. On the contrary, other neurotransmitters such as glycine, serotonin, gamma-aminobutyric acid, and dopamine do not provoke significant changes in the nanopore electronic signal due to their inability to displace the metal ion and form a stable complex with Ni 2+ ion. The nanofluidic sensor exhibits high sensitivity, specificity and reusability towards histamine detection and can then be used to monitor the concentration of biological important neurotransmitters. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Driving Performance and User's Evaluation of Self-Balancing Personal Mobility Vehicle with a Pedal Driving Mechanism

    Directory of Open Access Journals (Sweden)

    Seonghee Jeong

    2015-07-01

    Full Text Available In this paper, we propose a self-balancing personal mobility vehicle with a hybrid driving mechanism, called as Wi-PMP, and discuss its features from the perspectives of its power-assist driving performance and a rider's evaluation. The mobility vehicle consists of a wheeled inverted pendulum type mobile platform, and a hybrid driving mechanism that can use human and motor power together for driving. By performing a bump driving, a slope driving, and a outdoor driving experiment, we confirm that the proposed hybrid mechanism is valid for the integration of human and motor power, and is effective to increase the driving power and reduce electrical load on motors and batteries. We conducted several experiments to investigate the rider's evaluation on a sit-riding method compared to a stand-riding one. The questionnaire results showed that a rider felt more comfortable in the case of the sit-riding method when getting on and off, and when driving the mobility vehicle. This implies that riding-type self-balancing vehicles such as Wi-PMP have the potential to become familiar personal mobility vehicles in daily life.

  18. Mechanical Design Engineering Enabler Project wheel and wheel drives

    Science.gov (United States)

    Nutt, Richard E.; Couch, Britt K.; Holley, John L., Jr.; Garris, Eric S.; Staut, Paul V.

    1992-01-01

    Our group was assigned the responsibility of designing the wheel and wheel drive system for a proof-of-concept model of the lunar-based ENABLER. ENABLER is a multi-purpose, six wheeled vehicle designed to lift and transport heavy objects associated with the construction of a lunar base. The resulting design was based on the performance criteria of the ENABLER. The drive system was designed to enable the vehicle to achieve a speed of 7 mph on a level surface, climb a 30 percent grade, and surpass a one meter high object and one meter wide crevice. The wheel assemblies were designed to support the entire weight of the vehicle on two wheels. The wheels were designed to serve as the main component of the vehicle's suspension and will provide suitable traction for lunar-type surfaces. The expected performance of the drive system for the ENABLER was influenced by many mechanical factors. The expected top speed on a level sandy surface is 4 mph instead of the desired 7 mph. This is due to a lack of necessary power at the wheels. The lack of power resulted from dimension considerations that allowed only an eight horsepower engine and also from mechanical inefficiencies of the hydraulic system. However, the vehicle will be able to climb a 30 percent grade, surpass a one meter high object and one meter wide crevice. The wheel assemblies will be able to support the entire weight of the vehicle on two wheels. The wheels will also provide adequate suspension for the vehicle and sufficient traction for lunar-type surfaces.

  19. Electromagnetic analysis of control element drive mechanism for KSNP

    International Nuclear Information System (INIS)

    Kim, H. M.; Kim, I. G.; Kim, I. Y.

    2002-01-01

    The magnetic jack type Control Element Drive Mechanism (CEDM) for Korean Standard Nuclear Power Plant (KSNP) is an electromechanical device which provides controlled linear motion to the Control Element Assembly (CEA) through the Extension Shaft Assembly (ESA) in response to operational signals received from the Control Element Drive Mechanism Control System (CEDMCS). The CEDM is operated by applying localized magnetic flux fields to movable latch and lift magnets, which are in the coolant pressure boundary. The CEDM design had been developed through electromechanical testing of the system including the magnetic force lifting the ESA. But it will be inefficient if parametric studies should be performed to improve the CEDM by test due to the consumption of high cost and long duration. So it becomes necessary to develop a computational model to simulate the electromagnetic characteristics of the CEDM to improve the CEDM design efficiently. In this paper, the electromagnetic analysis using a 2D finite element model has been carried out to simulate magnetic force of the lift magnet of the CEDM, to provide effective evaluation between leakage flux and lift force and to compare with test results. Analysis results show the lift force satisfied the test results and design requirement and the lift force depend on the shape of the components, leakage flux and B-H curve

  20. Study on dynamic lifting characteristics of control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao

    2012-01-01

    Based on the equations of the electric circuit and the magnetic circuit and analysis of the dynamic lifting process for the control rod drive mechanism (CRDM), coupled magnetic-electric-mechanical equations both for the static status and the dynamic status are derived. The analytical method is utilized to obtain the current and the time when the lift starts. The numerical simulation method of dynamic analysis recommended by ASME Code is utilized to simulate the dynamic lifting process of CRDM, and the dynamic features of the system with different design gaps are studied. Conclusions are drawn as: (1) the lifting-start time increases with the design gap, and the time for the lifting process is longer with larger gaps; (2) the lifting velocity increases with time; (3) the lifting acceleration increases with time, and with smaller gaps, the impact acceleration is larger. (author)

  1. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Wilson, J.F.; Sherwood, D.G.

    1982-01-01

    A mechanical spectral shift reactor comprises a reactive core having fuel assemblies accommodating both water displacer elements and neutron absorbing control rods for selectively changing the volume of water-moderator in the core. The fuel assemblies with displacer and control rods are arranged in alternating fashion so that one displacer element drive mechanism may move displacer elements in more than one fuel assembly without interfering with the movement of control rods of a corresponding control rod drive mechanisms. (author)

  2. A superconducting linear motor drive for a positive displacement bellows pump for use in the g-2 cryogenics system

    International Nuclear Information System (INIS)

    Green, M.A.

    1994-10-01

    Forced two-phase cooling of indirectly cooled magnets requires circulation of liquid helium through the magnet cooling channel. A bellows helium pump is one possible way of providing helium flow to a magnet cooling system. Since the bellows type of helium pump is immersed in liquid helium, a superconducting linear motor drive appears to be an attractive option. This report describes a linear motor drive that employs oriented permanent magnet materials such as samarium-cobalt as the stator magnet system and a superconducting loud speaker voice coil type of drive as the armature of the linear motor. This report examines drive motor requirements for a helium pump

  3. Mechanisms of defect production and atomic mixing in high energy displacement cascades: A molecular dynamics study

    International Nuclear Information System (INIS)

    Diaz de la Rubia, T.; Guinan, M.W.

    1991-01-01

    We have performed molecular dynamics computer simulation studies of displacement cascades in Cu at low temperature. For 25 keV recoils we observe the splitting of a cascade into subcascades and show that cascades in Cu may lead to the formation of vacancy and interstitial dislocation loops. We discuss a new mechanism of defect production based on the observation of interstitial prismatic dislocation loop punching from cascades at 10 K. We also show that below the subcascade threshold, atomic mixing in the cascade is recoil-energy dependent and obtain a mixing efficiency that scales as the square root of the primary recoil energy. 44 refs., 12 figs

  4. Fluorescent sensors for selective detection of thiols: expanding the intramolecular displacement based mechanism to new chromophores.

    Science.gov (United States)

    Niu, Li-Ya; Zheng, Hai-Rong; Chen, Yu-Zhe; Wu, Li-Zhu; Tung, Chen-Ho; Yang, Qing-Zheng

    2014-03-21

    Biological thiols, including cysteine (Cys), homocystein (Hcy) and glutathione (GSH), play crucial roles in maintaining the appropriate redox status of biological systems. An abnormal level of biothiols is associated with different diseases, therefore, the discrimination between them is of great importance. Herein, we present two fluorescent sensors for selective detection of biothiols based on our recently reported intramolecular displacement mechanism. We expanded this mechanism to commercially available chromophores, 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and heptamethine cyanine dye IR-780. The sensors operate by undergoing displacement of chloride by thiolate. The amino groups of Cys/Hcy further replace the thiolate to form amino-substituted products, which exhibit dramatically different photophysical properties compared to sulfur-substituted products from the reaction with GSH. NBD-Cl is highly selective towards Cys/Hcy and exhibits significant fluorescence enhancement. IR-780 showed a variation in its fluorescence ratio towards Cys over other thiols. Both of the sensors can be used for live-cell imaging of Cys. The wide applicability of the mechanism may provide a powerful tool for developing novel fluorescent sensors for selective detection of biothiols.

  5. Fast-Response electric drives of Mechanical Engineering objects

    Science.gov (United States)

    Doykina, L. A.; Bukhanov, S. S.; Gryzlov, A. A.

    2018-03-01

    The article gives a solution to the problem of increasing the speed in the electrical drives of machine-building enterprises due to the application of a structure with ISC control. In this case, it is possible to get rid of the speed sensors. It is noted that in this case no circulating pulsations are applied to the input of the control system, caused by a non-identical interface between the sensor and the shaft of the operating mechanism. For detailed modeling, a mathematical model of an electric drive with distributed parameters was proposed. The calculation of such system was carried out by the finite element method. Taking into account the distributed characteristic of the system parameters allowed one to take into account the discrete nature of the electric machine’s work. The simulation results showed that the response time in the control circuit is estimated at a time constant of 0.0015, which is about twice as fast as in traditional vector control schemes.

  6. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section...

  7. Performance of a seeder according to the displacement velocity and furrowing mechanism for fertilizer deposition

    Directory of Open Access Journals (Sweden)

    Viviane C. dos Santos

    2016-03-01

    Full Text Available ABSTRACT Agribusiness daily increases the demand for machinery with better efficiency, seeking to reduce operating costs and improve the quality of the sowing process. The objective of present study was to evaluate the quality of the longitudinal seed distribution and the operating performance of a seeder-fertilizer according to displacement velocity and furrowing mechanism for fertilizer deposition. The assay was conducted in the experimental area of the Department of Agricultural Engineering of the Federal University of Ceará. The experimental design was randomized blocks, in a 2 x 3 factorial, with four replicates with two furrowing mechanisms for fertilizer deposition (double disc and shank and three displacement velocities (4.7, 6.3 and 8.2 km h-1. The results demonstrate that for the quality of seed distribution, the best performance was obtained with the use of the shank at velocity of 6.3 km h-1. The tractor-seeder set provided better operating performance using the disc, which promoted the lowest specific consumption at the velocity of 4.7 km h-1.

  8. Micropillar displacements by cell traction forces are mechanically correlated with nuclear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qingsen; Makhija, Ekta; Hameed, F.M. [Mechanobiology Institute, National University of Singapore (Singapore); Shivashankar, G.V., E-mail: shiva.gvs@gmail.com [Mechanobiology Institute, National University of Singapore (Singapore); Department of Biological Sciences, National University of Singapore (Singapore)

    2015-05-29

    Cells sense physical cues at the level of focal adhesions and transduce them to the nucleus by biochemical and mechanical pathways. While the molecular intermediates in the mechanical links have been well studied, their dynamic coupling is poorly understood. In this study, fibroblast cells were adhered to micropillar arrays to probe correlations in the physical coupling between focal adhesions and nucleus. For this, we used novel imaging setup to simultaneously visualize micropillar deflections and EGFP labeled chromatin structure at high spatial and temporal resolution. We observed that micropillar deflections, depending on their relative positions, were positively or negatively correlated to nuclear and heterochromatin movements. Our results measuring the time scales between micropillar deflections and nucleus centroid displacement are suggestive of a strong elastic coupling that mediates differential force transmission to the nucleus. - Highlights: • Correlation between focal adhesions and nucleus studied using novel imaging setup. • Micropillar and nuclear displacements were measured at high resolution. • Correlation timescales show strong elastic coupling between cell edge and nucleus.

  9. Mechanisms of the negative synergy effect between electron cyclotron current drive and lower hybrid current drive in tokamak

    International Nuclear Information System (INIS)

    Chen Shaoyong; Hong Binbin; Tang Changjian; Yang Wen; Zhang Xinjun

    2013-01-01

    The synergy current drive by combining electron cyclotron wave (ECW) with lower hybrid wave (LHW) can be used to either increase the noninductive current drive efficiency or shape the plasma current profile. In this paper, the synergy current drive by ECW and LHW is studied with numerical simulation. The nonlinear relationship between the wave powers and the synergy current of ECW and LHW is revealed. When the LHW power is small, the synergy current reduces as the ECW power increases, and the synergy current is even reduced to lower than zero, which is referred as negative synergy in the this context. Research shows that the mechanism of the negative synergy is the peaking effect of LHW power profile and the trapped electrons effect. The present research is helpful for understanding the physics of synergy between electron cyclotron current drive and lower hybrid current drive, it can also instruct the design of experiments. (authors)

  10. Preliminary aseismic analysis on bolts of driving mechanism in absorption sphere shutdown system

    International Nuclear Information System (INIS)

    Chen Feng; Li Tianjin; Zhang Zhengming; Huang Zhiyong; Bo Hanliang

    2012-01-01

    The absorption sphere shutdown system performs an important role in reactivity regulating and control. Driving mechanism is a set of key mechanical moving parts which is used to control falling of absorption spheres in absorption sphere shutdown system. It is about 5 m for driving mechanism with the slim structure, which is connected with the upper supported plate of metal reactor internals through storage vessel with bolts. Both the storage vessel and driving mechanism are equipment of seismic classification I. It is significant to calculate and check the bolts strength of driving mechanism. In this paper, complicate structure of driving mechanism was simplified to three variable cross sections and statically indeterminate problem was solved. The bolts at the bottom and on the top of the storage vessel were calculated and checked. The preliminary results indicate that the bolts strength is reliable and safe, and the supporting force at the most weak point of driving mechanism is as well obtained. (authors)

  11. Flat Optical Fiber Daylighting System with Lateral Displacement Sun-Tracking Mechanism for Indoor Lighting

    Directory of Open Access Journals (Sweden)

    Ngoc Hai Vu

    2017-10-01

    Full Text Available An essential impact which can improve the indoor environment and save on power consumption for artificial lighting is utilization of daylight. Optical fiber daylighting technology offers a way to use direct daylight for remote spaces in a building. However, the existing paradigm based on the precise orientation of sunlight concentrator toward the Sun is very costly and difficult to install on the roof of buildings. Here, we explore an alternative approach using mirror-coated lens array and planar waveguide to develop a flat optical fiber daylighting system (optical fiber daylighting panel with lateral displacement Sun-tracking mechanism. Sunlight collected and reflected by each mirror-coated lens in a rectangular lens array is coupled into a planar waveguide using cone prisms placed at each lens focus. This geometry yields a thin, flat profile for Sunlight concentrator. Our proposed concentrating panel can be achieved with 35 mm thickness while the concentrator’s width and length are 500 mm × 500 mm. The commercial optical simulation tool (LightToolsTM was used to develop the simulation models and analyze the system performance. Simulation results based on the designed system demonstrated an optical efficiency of 51.4% at a concentration ratio of 125. The system can support utilizing a lateral displacement Sun-tracking system, which allows for replacing bulky and robust conventional rotational Sun-tracking systems. This study shows a feasibility of a compact and inexpensive optical fiber daylighting system to be installed on the roof of buildings.

  12. Clays causing adhesion with tool surfaces during mechanical tunnel driving

    Science.gov (United States)

    Spagnoli, G.; Fernández-Steeger, T.; Stanjek, H.; Feinendegen, M.; Post, C.; Azzam, R.

    2009-04-01

    During mechanical excavation with a tunnel boring machine (TBM) it is possible that clays stick to the cutting wheel and to other metal parts. The resulting delays in the progress of construction work, cause great economic damage and often disputes between the public awarding authorities and executing companies. One of the most important factors to reduce successfully the clay adhesion is the use of special polymers and foams. But why does the clay stick to the metal parts? A first step is to recognize which kind of clay mineralogy shows serious adhesion problems. The mechanical properties of clay and clay suspensions are primarily determined by surface chemistry and charge distribution at the interfaces, which in turn affect the arrangement of the clay structure. As we know, clay is a multi-phase material and its behaviour depends on numerous parameters such as: clay mineralogy, clay fraction, silt fraction, sand fraction, water content, water saturation, Atterberg limits, sticky limit, activity, cation exchange capacity, degree of consolidation and stress state. It is therefore likely that adhesion of clay on steel is also affected by these clay parameters. Samples of clay formations, which caused problems during tunnel driving, will be analyzed in laboratory. Mineralogical analyses (diffractometry, etc.) will be carried out to observe which minerals are responsible for adherence problems. To manipulate the physical properties, batch tests will be carried out in order to eliminate or reduce the adhesion on tool surfaces through variation of the zeta potential. Second step is the performance of vane shear tests on clay samples. Different pore fluid (distilled water, pure NaCl solution, ethanol and methanol) will be used to study the variation of the mechanical behaviour of clay depending on the dielectric constant of the fluids. This project is funded by the German Federal Ministry of Education and Research (BMBF) and the DFG (German Research Foundation) in the

  13. The thermohaline driving mechanism of oceanic jet streams

    Science.gov (United States)

    Csanady, G. T.

    1982-01-01

    In a series of publications dealing with the circulation of the North Atlantic, Worthington (1959, 1972, 1976, 1977) has challenged the widely accepted notion that the Gulf Stream system is entirely wind-driven. He was able to demonstrate that the Gulf Stream over its most intense portion south of New England generally intensifies in winter. Worthington postulates that strong surface cooling in winter is the cause of Gulf Stream intensification, i.e., he believes that a thermal mechanism is partially responsible for driving the Gulf Stream. Worthington speaks of 'anticyclogenesis' and of a 'fresh charge of energy' which the Gulf Stream receives at the end of each (severe) winter. A pattern of thermoline circulation arising in the upper layers of the Stream could play a role similar to that of the Hadley circulation in the atmosphere, which derives the subtropical jet stream. The present investigation is concerned with the examination of such a possibility, taking into account the employment of a two-layer model.

  14. Wheelchair ergonomic hand drive mechanism use improves wrist mechanics associated with carpal tunnel syndrome

    OpenAIRE

    Lisa A. Zukowski, MA; Jaimie A. Roper, MS; Orit Shechtman, PhD, OTR/L; Dana M. Otzel, PhD; Patty W. Hovis, MSESS; Mark D. Tillman, PhD

    2015-01-01

    Among conventional manual wheelchair (CMW) users, 49% to 63% experience carpal tunnel syndrome (CTS) that is likely induced by large forces transmitted through the wrist and extreme wrist orientations. The ergonomic hand drive mechanism (EHDM) tested in this study has been shown to utilize a more neutral wrist orientation. This study evaluates the use of an EHDM in terms of wrist orientations that may predispose individuals to CTS. Eleven adult full-time CMW users with spinal cord injury part...

  15. Working principle and structure characteristics analysis of the reactivity control drive mechanism

    International Nuclear Information System (INIS)

    Zhao Tianyu; Huang Zhiyong; Chen Feng; He Xuedong

    2010-01-01

    The startup, power regulation and safety shutdown of the nuclear reactor are operated by the reactivity control devices. Reactivity control drive mechanism is a key mechanical transmission component, which directly control the location of the neutron absorber in the core. Its working condition is complex, and its service life should be long., which requires high reliability. PWR as well as newly developed different type of reactors have different control devices drive mechanism. This paper mainly do analysis and comparison about the working environment, mechanical transmission principle, structure, performance, service life and other aspects of PWR, HTR control devices drive mechanism. In addition, this paper is also based on the working principles of reactive control devices drive mechanism, also consider the trends of its design and test verification by the international countries, and discussed the method and feasibility of improving and perfecting the structure and function of drive mechanism. (authors)

  16. Three-dimensional linear fracture mechanics analysis by a displacement-hybrid finite-element model

    International Nuclear Information System (INIS)

    Atluri, S.N.; Kathiresan, K.; Kobayashi, A.S.

    1975-01-01

    This paper deals with a finite-element procedures for the calculation of modes I, II and III stress intensity factors, which vary, along an arbitrarily curved three-dimensional crack front in a structural component. The finite-element model is based on a modified variational principle of potential energy with relaxed continuity requirements for displacements at the inter-element boundary. The variational principle is a three-field principle, with the arbitrary interior displacements for the element, interelement boundary displacements, and element boundary tractions as variables. The unknowns in the final algebraic system of equations, in the present displacement hybrid finite element model, are the nodal displacements and the three elastic stress intensity factors. Special elements, which contain proper square root and inverse square root crack front variations in displacements and stresses, respectively, are used in a fixed region near the crack front. Interelement displacement compatibility is satisfied by assuming an independent interelement boundary displacement field, and using a Lagrange multiplier technique to enforce such interelement compatibility. These Lagrangean multipliers, which are physically the boundary tractions, are assumed from an equilibrated stress field derived from three-dimensional Beltrami (or Maxwell-Morera) stress functions that are complete. However, considerable care should be exercised in the use of these stress functions such that the stresses produced by any of these stress function components are not linearly dependent

  17. Nutrients and Hydrology Indicate the Driving Mechanisms of Peatland Surface Patterning

    NARCIS (Netherlands)

    Eppinga, M.B.; Ruiter, de P.C.; Wassen, M.J.; Rietkerk, M.

    2009-01-01

    Peatland surface patterning motivates studies that identify underlying structuring mechanisms. Theoretical studies so far suggest that different mechanisms may drive similar types of patterning. The long time span associated with peatland surface pattern formation, however, limits possibilities for

  18. Determination of The Mechanical Power in Belt Conveyor's Drive System in Industrial Conditions

    Science.gov (United States)

    Król, Robert; Kaszuba, Damian; Kisielewski, Waldemar

    2016-10-01

    Mechanical power is a value which carries a significant amount of information on the properties of the operating status of the machine analysed. The value of mechanical power reflects the degree of load of the drive system and of the entire machine. It is essential to determine the actual efficiency of the drive system η [%], which is the key parameter of the energy efficiency of the drive system. In the case of a single drive of a belt conveyor the actual efficiency is expressed as the ratio of mechanical output power Pm [W] at the drive pulley shaft to active electrical power drawn by the motor Pe [W]. Furthermore, the knowledge about the mechanical power from all drives of the multiple driven belt conveyor allows for the analysis of load distribution between the drives. In case of belt conveyor, the mechanical power Pm [W] generated by the drive at the drive pulley's shaft is equal to its angular velocity ω [rad / s] multiplied by the torque T [Nm]. The measurement of angular velocity is relatively easy and can be realized with the use of a tachometer or can be determined on the basis of linear velocity of the conveyor belt during belt conveyor's steady state operation. Significantly more difficult to perform in industrial conditions is the measurement of the torque. This is due to the operational conditions of belt conveyors (e.g. dustiness, high humidity, high temperature) and tight assembly of the drive components without the possibility of their disassembly. It makes it difficult or even impossible to measure the torque using a number of the techniques available, causing an individual approach to each object of research. The paper proposes a measurement methodology allowing to determine the mechanical power in belt conveyors drives which are commonly used in underground and surface mining. The paper presents result of the research into mechanical power in belt conveyor's drive carried out in underground mine conditions.

  19. Optical Mass Displacement Tracking: A simplified field calibration method for the electro-mechanical seismometer.

    Science.gov (United States)

    Burk, D. R.; Mackey, K. G.; Hartse, H. E.

    2016-12-01

    We have developed a simplified field calibration method for use in seismic networks that still employ the classical electro-mechanical seismometer. Smaller networks may not always have the financial capability to purchase and operate modern, state of the art equipment. Therefore these networks generally operate a modern, low-cost digitizer that is paired to an existing electro-mechanical seismometer. These systems are typically poorly calibrated. Calibration of the station is difficult to estimate because coil loading, digitizer input impedance, and amplifier gain differences vary by station and digitizer model. Therefore, it is necessary to calibrate the station channel as a complete system to take into account all components from instrument, to amplifier, to even the digitizer. Routine calibrations at the smaller networks are not always consistent, because existing calibration techniques require either specialized equipment or significant technical expertise. To improve station data quality at the small network, we developed a calibration method that utilizes open source software and a commonly available laser position sensor. Using a signal generator and a small excitation coil, we force the mass of the instrument to oscillate at various frequencies across its operating range. We then compare the channel voltage output to the laser-measured mass displacement to determine the instrument voltage sensitivity at each frequency point. Using the standard equations of forced motion, a representation of the calibration curve as a function of voltage per unit of ground velocity is calculated. A computer algorithm optimizes the curve and then translates the instrument response into a Seismic Analysis Code (SAC) poles & zeros format. Results have been demonstrated to fall within a few percent of a standard laboratory calibration. This method is an effective and affordable option for networks that employ electro-mechanical seismometers, and it is currently being deployed in

  20. Physical mechanisms of gas and perfluoron retinopexy and sub-retinal fluid displacement

    International Nuclear Information System (INIS)

    Foster, William J; Chou, Tom

    2004-01-01

    Injection of gas into the eye, followed by face-down positioning, is a common protocol for the reseating of the retina in posterior and superior retinal tears and breaks. The physical mechanism by which injected gas helps reattach retinal flaps is often ascribed to the 'buoyancy' force of the injected gas bubble. The various forces at play in this system (surface tension and buoyancy) were calculated and compared. The results are extended to the case in which the retina is intact (pneumatic displacement of blood) and to the use of intraocular perfluoron (n-perfluorooctane). We show that buoyancy forces are applicable only for gas or n-perfluorooctane bubbles that are smaller than the detached retina and that do not invade underneath the retina. For larger bubbles, as is normally used in reattachment protocols, we show that it is the interfacial tension that reattaches the retina. The range of angles within which patients can position, and still maintain a gas-vitreous interface along a tear is calculated as a function of the volume of injected gas and size of the tear. The maximum retinal flap size that can be reattached using surface tension forces is also estimated

  1. A Data Acquisition System Based on DSP for Mechanical Nanoscale Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Yong Yu

    2012-01-01

    Full Text Available This paper presents a data acquisition system based on DSP for a mechanical nanoscale displacement sensor where normal strain gauges are utilized. The key challenge of the data acquisition system is that the original signal is very weak. So the data acquisition system should provide large enough amplification ratio and good noise control capability. We use three strategies to solve above problems. First, two devices, an instrumentation amplifier and an analog to digital converter, are used to construct two stage amplification to provide enough amplification ratio. Second, an analog filter and a digital filter are used to eliminate noise. Third, we carefully choose high precision devices in the system. To test the system, we present a series of experiments. The experimental results validate that the system has good performance at weak signal detection. Furthermore, the system has advantages of large amplification ratio, good noise control capability, and good repeatability. Above all, the whole system can achieve the resolution of 3 nm.

  2. Roller-chain Drives Mechanics using Multibody Dynamics Tools

    DEFF Research Database (Denmark)

    Ambrosio, Jorge A. C.; Hansen, John Michael

    1999-01-01

    An integrated model for the simulation of roller-chain drives based on a multibody dynamics methodology is presented here in order to describeits complex dynamic behavior. The chain is modeled by masses lumped at the roller locations and connected by translational spring-damper elements in order...

  3. Evidence for competitive displacement of Ceratitis cosyra by the invasive fruit fly Bactrocera invadens (Diptera: Tephritidae) on mango and mechanisms contributing to the displacement.

    Science.gov (United States)

    Ekesi, Sunday; Billah, Maxwell K; Nderitu, Peterson W; Lux, Slawomir A; Rwomushana, Ivan

    2009-06-01

    Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) invaded Kenya in 2003. Before the arrival of B. invadens, the indigenous fruit fly species Ceratitis cosyra (Walker) was the predominant fruit fly pest of mango (Mangifera indica L.). Within 4 yr of invasion, B. invadens has displaced C. cosyra and has become the predominant fruit fly pest of mango, constituting 98 and 88% of the total population in traps and mango fruit at Nguruman, respectively. We tested two possible mechanisms responsible for the displacement namely; resource competition by larvae within mango fruit and aggression between adult flies. Under interspecific competition, larval duration in B. invadens was significantly shorter (6.2 +/- 0.6-7.3 +/- 0.3 d) compared with C. cosyra (8.0 +/- 1.2-9.4 +/- 0.4 d). Pupal mass in C. cosyra was affected by competition and was significantly reduced (7.4 +/- 0.3-9.6 +/- 0.6 mg) under competitive interaction compared with the controls (12.1 +/- 1.5-12.8 +/- 1.1 mg). Interspecific competition also had a significant adverse effect on C. cosyra eclosion, with fewer adults emerging under co-infestation compared with the controls. Interference competition through aggressive behavior showed that fewer C. cosyra (3.1 +/- 0.8) landed on mango dome compared with the controls (14.2 +/- 1.5) when adults were mixed with B. invadens adults in Plexiglas cages. Similarly the number of times C. cosyra was observed ovipositing was significantly lower (0.2 +/- 0.2) under competitive interaction compared with the controls (6.1 +/- 1.8). Aggressive encounters in the form of lunging/ head-butting and chasing off other species from the mango dome was higher for B. invadens compared with C. cosyra. Our results suggest that exploitative competition through larval scrambling for resources and interference competition through aggressive behaviors of the invader are important mechanisms contributing to the displacement of C. cosyra by B. invadens in mango agroecosystems.

  4. The seating mechanics of head-neck modular tapers in vitro: Load-displacement measurements, moisture, and rate effects.

    Science.gov (United States)

    Ouellette, Eric S; Shenoy, Aarti A; Gilbert, Jeremy L

    2017-09-08

    The mechanically assisted crevice corrosion performance of head-neck modular tapers is a significant concern in orthopedic biomaterials. Fretting crevice corrosion processes in modular tapers are thought to be influenced by a wide array of factors including seating mechanics of the junction, hence there is a need for in vitro test methods that can assess their performance. This study presented a test method to directly measure the load-displacement seating mechanics of modular tapers and used this method to compare the seating mechanics for different tapers, moisture, seating loads and seating rates. Seating mechanics were explored whereby the instantaneous load-displacement behavior of the head seating onto the neck is captured and used to define the mechanics of seating. Two distinct taper design/material combinations were assembled wet or dry using axially applied loads (500, 1,000, 2,000, and 4,000 N) at two loading rates of 100 and 10 4  N/s (n = 5 for each condition) using a servohydraulic test frame. The results showed that pull-off strength scaled with seating load and ranged between 43% and 68% of seating load depending on sample and wetness. Tapers seated wet had higher pull-off strengths (2,200 ± 300 N) than those seated dry (1,800 ± 200 N, p mechanics (load-displacement plots) varied due to sample type and due to wetness with differences in seating energy, seating stiffness, and seating displacement. These results show the detailed mechanics of seating during assembly and provide significant insight into the complex interplay of factors associated with even "ideal" seating (axial, quasistatic) loading. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-9, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  5. Speed Controlled Belt Conveyors: Drives and Mechanical Considerations

    OpenAIRE

    BEBIC, M. Z.; RISTIC, L. B.

    2018-01-01

    The paper presents variable speed belt conveyor system where the reference speed is changed in order to achieve improved energy efficiency of operation. The recorded measurements show that belt tension varies within the same limits as under constant speed operation. These results introduce a new insight of the present state of the art in variable speed belt conveyor drives. The system is realized with remote control from the control center on an open pit mine. The structure of...

  6. Anomalous Scaling Behaviors in a Rice-Pile Model with Two Different Driving Mechanisms

    International Nuclear Information System (INIS)

    Zhang Duanming; Sun Hongzhang; Li Zhihua; Pan Guijun; Yu Boming; Li Rui; Yin Yanping

    2005-01-01

    The moment analysis is applied to perform large scale simulations of the rice-pile model. We find that this model shows different scaling behavior depending on the driving mechanism used. With the noisy driving, the rice-pile model violates the finite-size scaling hypothesis, whereas, with fixed driving, it shows well defined avalanche exponents and displays good finite size scaling behavior for the avalanche size and time duration distributions.

  7. Seismic appraisal test of control rod drive mechanism of China experiment fast reactor

    International Nuclear Information System (INIS)

    Song Qing; Yang Hongyi; Jing Yueqing; Wen Jing; Liu Guijuan; Sun Lei

    2008-01-01

    The structure of the control rod drive mechanism in pool type sodium-cooled fast reactor is the characterized by long, thin, and geometric nonlinearity, and the seismic load is multiple activation. The anti-seismic evaluation is always paid great attention by the countries developing the technology worldwide. This article introduces the seismic appraisal test of the control rod drive mechanism of China Experimental Fast Reactor (CEFR) performed on a seismic platform which is vertical shaft style and multiple activation. The result of the test shows the structural integrity and the function of the control rod drive mechanism could meet the design requirements of the earthquake intensity. (authors)

  8. 14 CFR 29.923 - Rotor drive system and control mechanism tests.

    Science.gov (United States)

    2010-01-01

    ..., assuming that speed and torque limiting devices, if any, function properly. (i) Endurance tests; rotor....923 Rotor drive system and control mechanism tests. (a) Endurance tests, general. Each rotor drive... rotorcraft. (3) The test torque and rotational speed must be— (i) Determined by the powerplant limitations...

  9. Determination of the mechanical parameters of rock mass based on a GSI system and displacement back analysis

    Science.gov (United States)

    Kang, Kwang-Song; Hu, Nai-Lian; Sin, Chung-Sik; Rim, Song-Ho; Han, Eun-Cheol; Kim, Chol-Nam

    2017-08-01

    It is very important to obtain the mechanical paramerters of rock mass for excavation design, support design, slope design and stability analysis of the underground structure. In order to estimate the mechanical parameters of rock mass exactly, a new method of combining a geological strength index (GSI) system with intelligent displacment back analysis is proposed in this paper. Firstly, average spacing of joints (d) and rock mass block rating (RBR, a new quantitative factor), surface condition rating (SCR) and joint condition factor (J c) are obtained on in situ rock masses using the scanline method, and the GSI values of rock masses are obtained from a new quantitative GSI chart. A correction method of GSI value is newly introduced by considering the influence of joint orientation and groundwater on rock mass mechanical properties, and then value ranges of rock mass mechanical parameters are chosen by the Hoek-Brown failure criterion. Secondly, on the basis of the measurement result of vault settlements and horizontal convergence displacements of an in situ tunnel, optimal parameters are estimated by combination of genetic algorithm (GA) and numerical simulation analysis using FLAC3D. This method has been applied in a lead-zinc mine. By utilizing the improved GSI quantization, correction method and displacement back analysis, the mechanical parameters of the ore body, hanging wall and footwall rock mass were determined, so that reliable foundations were provided for mining design and stability analysis.

  10. Experimental research on microscopic displacement mechanism of CO2-water alternative flooding in low permeability reservoir

    Science.gov (United States)

    Han, Hongyan; Zhu, Weiyao; Long, Yunqian; Song, Hongqing; Huang, Kun

    2018-02-01

    This paper provides an experimental method to deal with the problems of low oil recovery ratio faced with water flooding utilizing the CO2/water alternate displacement technology. A series of CO2/water alternate flooding experiments were carried out under 60°C and 18.4MPa using high temperature / pressure microscopic visualization simulation system. Then, we used the image processing technique and software to analyze the proportion of remaining oil in the displacement process. The results show that CO2 can extract the lighter chemical components in the crude oil and make it easier to form miscible phase, which can reduce the viscosity and favorable mobility ratio of oil. What’s more, the displacement reduces the impact of gas channeling, which can achieve an enlarged sweeping efficiency to improve filtration ability. In addition, the CO2 dissolved in oil and water can greatly reduce the interfacial tension, which can increase the oil displacement efficiency in a large extent. Generally speaking, the recovery rate of residual oil in the micro - model can be elevated up to 15.89% ∼ 16.48% under formation condition by alternate displacement.

  11. DYNAMIC ANALYSIS OF HYDRAULIC DRIVE OF TILTING PLATFORM MECHANISM OF DUMP TRUCK

    Directory of Open Access Journals (Sweden)

    P. Kishkevich

    2011-01-01

    Full Text Available Object of research – hydraulic drive of tilting platform mechanism of dump truck. We pro-pose a dynamic model of the hydraulic system. The model takes into account the cyclic operation (lifting, lowering the platform.

  12. DYNAMIC ANALYSIS OF HYDRAULIC DRIVE OF TILTING PLATFORM MECHANISM OF DUMP TRUCK

    OpenAIRE

    P. Kishkevich; A. Safonau; I. Selivonchik; P. Bartosh

    2011-01-01

    Object of research – hydraulic drive of tilting platform mechanism of dump truck. We pro-pose a dynamic model of the hydraulic system. The model takes into account the cyclic operation (lifting, lowering the platform).

  13. Mechanisms underlying center of pressure displacements in obese subjects during quiet stance

    Directory of Open Access Journals (Sweden)

    Priano Lorenzo

    2011-04-01

    Full Text Available Abstract Objective the aim of this study was to assess whether reduced balance capacity in obese subjects is secondary to altered sensory information. Design cross sectional study. Subjects 44 obese (BMI = 40.6 ± 4.6 kg/m2 , age = 34.2 ± 10.8 years, body weight: 114,0 ± 16,0 Kg, body height 167,5 ± 9,8 cm and 20 healthy controls (10 females, 10 males, BMI: 21.6 ± 2.2 kg/m2, age: 30.5 ± 5.5 years, body weight: 62,9 ± 9,3 Kg, body height 170,1 ± 5,8 cm were enrolled. Measurements center of pressure (CoP displacements were evaluated during quiet stance on a force platform with eyes open (EO and closed (EC. The Romberg quotient (EC/EO was computed and compared between groups. Results we found statistically significant differences between obese and controls in CoP displacements (p 0.08. Conclusion the increased CoP displacements in obese subjects do not need an hypothesis about altered sensory information. The integration of different sensory inputs appears similar in controls and obese. In the latter, the increased mass, ankle torque and muscle activity may probably account for the higher CoP displacements.

  14. Development of an innovative reflector drive mechanism using magnetic repulsion force for 4S reactor

    International Nuclear Information System (INIS)

    Tsuji, K.; Watanabe, M.; Inagaki, H.; Nishikawa, A.; Takahashi, H.; Wakamatsu, M.; Matsumiya, H.; Nishiguchi, Y.

    2001-01-01

    A small sized fast reactor 4S: (Super Safe Small and Simple) which has a core of 10 - 30 years life time is controlled by reflectors. The reflector is required to be risen at very low speed to make up for the reactivity swing during operation. This report shows the development of an innovative reflector drive mechanism using magnetic repulsion force that can move at a several micrometer per one step. This drive mechanism has a passive shut down capability, and can eliminate reflector drive line. (author)

  15. Mortality and pulmonary mechanics in relation to respiratory system and transpulmonary driving pressures in ARDS.

    Science.gov (United States)

    Baedorf Kassis, Elias; Loring, Stephen H; Talmor, Daniel

    2016-08-01

    The driving pressure of the respiratory system has been shown to strongly correlate with mortality in a recent large retrospective ARDSnet study. Respiratory system driving pressure [plateau pressure-positive end-expiratory pressure (PEEP)] does not account for variable chest wall compliance. Esophageal manometry can be utilized to determine transpulmonary driving pressure. We have examined the relationships between respiratory system and transpulmonary driving pressure, pulmonary mechanics and 28-day mortality. Fifty-six patients from a previous study were analyzed to compare PEEP titration to maintain positive transpulmonary end-expiratory pressure to a control protocol. Respiratory system and transpulmonary driving pressures and pulmonary mechanics were examined at baseline, 5 min and 24 h. Analysis of variance and linear regression were used to compare 28 day survivors versus non-survivors and the intervention group versus the control group, respectively. At baseline and 5 min there was no difference in respiratory system or transpulmonary driving pressure. By 24 h, survivors had lower respiratory system and transpulmonary driving pressures. Similarly, by 24 h the intervention group had lower transpulmonary driving pressure. This decrease was explained by improved elastance and increased PEEP. The results suggest that utilizing PEEP titration to target positive transpulmonary pressure via esophageal manometry causes both improved elastance and driving pressures. Treatment strategies leading to decreased respiratory system and transpulmonary driving pressure at 24 h may be associated with improved 28 day mortality. Studies to clarify the role of respiratory system and transpulmonary driving pressures as a prognosticator and bedside ventilator target are warranted.

  16. Simulation of coupled flow and mechanical deformation using IMplicit Pressure-Displacement Explicit Saturation (IMPDES) scheme

    KAUST Repository

    El-Amin, Mohamed

    2012-01-01

    The problem of coupled structural deformation with two-phase flow in porous media is solved numerically using cellcentered finite difference (CCFD) method. In order to solve the system of governed partial differential equations, the implicit pressure explicit saturation (IMPES) scheme that governs flow equations is combined with the the implicit displacement scheme. The combined scheme may be called IMplicit Pressure-Displacement Explicit Saturation (IMPDES). The pressure distribution for each cell along the entire domain is given by the implicit difference equation. Also, the deformation equations are discretized implicitly. Using the obtained pressure, velocity is evaluated explicitly, while, using the upwind scheme, the saturation is obtained explicitly. Moreover, the stability analysis of the present scheme has been introduced and the stability condition is determined.

  17. On the Optimally Controlled Hydrostatic Mechanical Drive in Case of Flywheel Acceleration

    Directory of Open Access Journals (Sweden)

    V. A. Korsunskii

    2016-01-01

    Full Text Available An improving dynamic quality of vehicles and enhanced fuel efficiency are gained thanks to the combined power system (CPS, comprising a main energy source - internal combustion engine (ICE with an attained level of the power source - and an auxiliary energy source, i.e. an energy storage device (a flywheel.To solve this problem was developed a mathematical model of CPS comprising internal combustion engine and flywheel energy storage (FES with stepless drive.The stepless drive of the flywheel is made to be hydrostatic mechanical to raise the system efficiency. To reduce the drive weight and simplify the control system in the hydraulic part of the flywheel drive is used only one hydraulic unit being controlled.The paper presents a kinematic diagram of the track-type vehicle equipped with the CPS that has a hydrostatic mechanical drive of the flywheel and a mechanical transmission.A mathematical model of the system comprising an ICE, hydrostatic mechanical drive, and FES with stepless drive has been developed. This mathematical model was used to study the influence of ICE and flywheel drive parameters on the dynamic characteristics of the system.The paper estimates the impact of flywheel energy consumption, pressure in the hydraulic system, and control parameter of hydrostatic mechanical drive on the charging time of FES.The obtained piecewise linear law to control the regulation parameter of the hydraulic unit allows us to minimize the charging time of the flywheel at the short-term stops and in the parking area of a tracked vehicle equipped with a CPS.The causes affecting the performance of ‘ICE – drive – flywheel’ system in the course of the flywheel acceleration are a restricted maximum power of the engine, as well as a limited generating capacity, and a maximum flywheel drive hydro-system pressure.The obtained results allow us to determine rational parameters of the flywheel and the laws of drive control to provide their further

  18. Immunogenetic mechanisms driving norovirus GII.4 antigenic variation.

    Directory of Open Access Journals (Sweden)

    Lisa C Lindesmith

    epitopes and consequently, antibody-driven receptor switching; thus, protective herd immunity is a driving force in norovirus molecular evolution.

  19. Mass loss as a driving mechanism of tectonics of Enceladus

    Science.gov (United States)

    Czechowski, Leszek

    2015-04-01

    Summary We suggest that the mass loss from South Polar Terrain (SPT) is the main driving force of the following tectonic processes on Enceladus: subsidence of SPT, flow in the mantle and motion of plates. 1. Introduction Enceladus, a satellite of Saturn, is the smallest celestial body in the Solar System where volcanic activity is observed. Every second, the mass of ~200 kg is ejected into space from the South Polar Terrain (SPT) - [1, 2, 3]. The loss of matter from the body's interior should lead to global compression of the crust. Typical effects of compression are: thrust faults, folding and subduction. However, such forms are not dominant on Enceladus. We propose here special tectonic model that could explain this paradox. 2. Subsidence of SPT and tectonics The volatiles escape from the hot region through the fractures forming plumes in the space. The loss of the volatiles results in a void, an instability, and motion of solid matter into the hot region to fill the void. The motion includes : Subsidence of the 'lithosphere' of SPT. Flow of the matter in the mantle. Motion of plates adjacent to SPT towards the active region. If emerging void is being filled by the subsidence of SPT only, then the velocity of subsidence is ~0.05 mm-yr-1. However, all three types of motion are probably important, so the subsidence is slower but mantle flow and plates' motion also play a role in filling the void. Note that in our model the reduction of the crust area is not a result of compression but it is a result of the plate sinking. Therefore the compressional surface features do not have to be dominant. 3. Models of subsidence The numerical model of suggested process of subsidence is developed. It is based on the typical set of equation: Navier-Stokes equation for incompressible viscous liquid, equation of continuity and equation of heat conduction. The Newtonian and non-Newtonian rheologies are used. The preliminary results of the model indicate that the subsidence rate of

  20. Design of a Gear-Shifting Control Mechanism for 8-Speed Bicycle Drive Hub

    Directory of Open Access Journals (Sweden)

    Li-An Chen

    2013-12-01

    Full Text Available The multi-speed drive hub stored on the rear wheel of a bicycle is an important speed-changing device to adjust the pedaling force and driving speed. This paper proposes a feasible gear-shifting control mechanism of an 8-speed distributed-flow-type transmission mechanism. A transmission mechanism consisting of two parallel-connected transmission units and one differential unit is introduced first. Then, based on the clutching sequence table, the embodiment design of a gear-shifting control mechanism is presented to selectively control the engagement of pawl-and-ratchet clutches and slot-with-block clutches as well as govern the power-flow path. The power-flow path at each speed-stage of this 8-speed drive hub is analyzed to verify the feasibility of the proposed design.

  1. Diffusive, Displacive Deformations and Local Phase Transformation Govern the Mechanics of Layered Crystals: The Case Study of Tobermorite.

    Science.gov (United States)

    Tao, Lei; Shahsavari, Rouzbeh

    2017-07-19

    Understanding the deformation mechanisms underlying the mechanical behavior of materials is the key to fundamental and engineering advances in materials' performance. Herein, we focus on crystalline calcium-silicate-hydrates (C-S-H) as a model system with applications in cementitious materials, bone-tissue engineering, drug delivery and refractory materials, and use molecular dynamics simulation to investigate its loading geometry dependent mechanical properties. By comparing various conventional (e.g. shear, compression and tension) and nano-indentation loading geometries, our findings demonstrate that the former loading leads to size-independent mechanical properties while the latter results in size-dependent mechanical properties at the nanometer scales. We found three key mechanisms govern the deformation and thus mechanics of the layered C-S-H: diffusive-controlled and displacive-controlled deformation mechanisms, and strain gradient with local phase transformations. Together, these elaborately classified mechanisms provide deep fundamental understanding and new insights on the relationship between the macro-scale mechanical properties and underlying molecular deformations, providing new opportunities to control and tune the mechanics of layered crystals and other complex materials such as glassy C-S-H, natural composite structures, and manmade laminated structures.

  2. Coupling device of the control rod and of the drive mechanism

    International Nuclear Information System (INIS)

    Savary, F.

    1986-01-01

    The invention proposes a coupling device removable in which the connection between the upper head of the control rod and the drive mechanism is a real rigid fixing, in the mechanical sense of the term, suppressing longitudinal play and allowing to restrict the momenta occurring when locating the control rods [fr

  3. A Possible Mechanism for Driving Oscillations in Hot Giant Planets

    Energy Technology Data Exchange (ETDEWEB)

    Dederick, Ethan; Jackiewicz, Jason, E-mail: dederiej@nmsu.edu, E-mail: jasonj@nmsu.edu [New Mexico State University, Las Cruces, NM (United States)

    2017-03-10

    The κ -mechanism has been successful in explaining the origin of observed oscillations of many types of “classical” pulsating variable stars. Here we examine quantitatively if that same process is prominent enough to excite the potential global oscillations within Jupiter, whose energy flux is powered by gravitational collapse rather than nuclear fusion. Additionally, we examine whether external radiative forcing, i.e., starlight, could be a driver for global oscillations in hot Jupiters orbiting various main-sequence stars at defined orbital semimajor axes. Using planetary models generated by the Modules for Experiments in Stellar Astrophysics and nonadiabatic oscillation calculations, we confirm that Jovian oscillations cannot be driven via the κ -mechanism. However, we do show that, in hot Jupiters, oscillations can likely be excited via the suppression of radiative cooling due to external radiation given a large enough stellar flux and the absence of a significant oscillatory damping zone within the planet. This trend does not seem to be dependent on the planetary mass. In future observations, we can thus expect that such planets may be pulsating, thereby giving greater insight into the internal structure of these bodies.

  4. Andreas Acrivos Dissertation Award: Onset of Dynamic Wetting Failure - The Mechanics of High-Speed Fluid Displacement

    Science.gov (United States)

    Vandre, Eric

    2014-11-01

    Dynamic wetting is crucial to processes where a liquid displaces another fluid along a solid surface, such as the deposition of a coating liquid onto a moving substrate. Dynamic wetting fails when process speed exceeds some critical value, leading to incomplete fluid displacement and transient phenomena that impact a variety of applications, such as microfluidic devices, oil-recovery systems, and splashing droplets. Liquid coating processes are particularly sensitive to wetting failure, which can induce air entrainment and other catastrophic coating defects. Despite the industrial incentives for careful control of wetting behavior, the hydrodynamic factors that influence the transition to wetting failure remain poorly understood from empirical and theoretical perspectives. This work investigates the fundamentals of wetting failure in a variety of systems that are relevant to industrial coating flows. A hydrodynamic model is developed where an advancing fluid displaces a receding fluid along a smooth, moving substrate. Numerical solutions predict the onset of wetting failure at a critical substrate speed, which coincides with a turning point in the steady-state solution path for a given set of system parameters. Flow-field analysis reveals a physical mechanism where wetting failure results when capillary forces can no longer support the pressure gradients necessary to steadily displace the receding fluid. Novel experimental systems are used to measure the substrate speeds and meniscus shapes associated with the onset of air entrainment during wetting failure. Using high-speed visualization techniques, air entrainment is identified by the elongation of triangular air films with system-dependent size. Air films become unstable to thickness perturbations and ultimately rupture, leading to the entrainment of air bubbles. Meniscus confinement in a narrow gap between the substrate and a stationary plate is shown to delay air entrainment to higher speeds for a variety of

  5. THE DRIVING MECHANISM OF STARBURSTS IN GALAXY MERGERS

    International Nuclear Information System (INIS)

    Teyssier, Romain; Chapon, Damien; Bournaud, Frederic

    2010-01-01

    We present hydrodynamic simulations of a major merger of disk galaxies, and study the interstellar medium (ISM) dynamics and star formation (SF) properties. High spatial and mass resolutions of 12 pc and 4 x 10 4 M sun allow us to resolve cold and turbulent gas clouds embedded in a warmer diffuse phase. We compare lower-resolution models, where the multiphase ISM is not resolved and is modeled as a relatively homogeneous and stable medium. While merger-driven bursts of SF are generally attributed to large-scale gas inflows toward the nuclear regions, we show that once a realistic ISM is resolved, the dominant process is actually gas fragmentation into massive and dense clouds and rapid SF therein. As a consequence, SF is more efficient by a factor of up to ∼10 and is also somewhat more extended, while the gas density probability distribution function rapidly evolves toward very high densities. We thus propose that the actual mechanism of starburst triggering in galaxy collisions can only be captured at high spatial resolution and when the cooling of gas is modeled down to less than 10 3 K. Not only does our model reproduce the properties of the Antennae system, but it also explains the 'starburst mode' recently revealed in high-redshift mergers compared to quiescent disks.

  6. Qualification tests for PWR control element drive mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Yong; Jin, Choon Eon; Choi Suhn [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-01-01

    It is necessary to perform the qualification test for the magnetic jack type CEDM to show the design compatibility because the CEDM is composed of many mechanical and electrical components complicatedly. ABB-CE performed various qualification tests during the development of the System80 CEDM to which Korea Standard Nuclear Plant (KSNP) CEDM referred. The qualification test for the CEDM is classified into the performance test and the dynamic test. The performance test is to verify operability of the CEDM, and the dynamic test is to find dynamic characteristics and to verify the structural integrity if the CEDM for the seismic accidents. Described in this report are the test requirements, the test facilities and the test methods for the performance and the dynamic qualification tests of the PWR magnetic jack type CEDM. The impacts of the design changes in the Korea Next Generation Reactor (KNGR) on the KSNP CEDM were analyzed to present the necessity for the tests. This report also proposes the facilities to perform the tests in KAERI including reasonable schedule for the tests. Attached to this report is the summary of qualification tests of System 80 CEDM performed by ABB-CE. 20 figs., 16 tabs., 21 refs. (Author) .new.

  7. Control rod driving mechanism of reactor, control device and operation method therefor

    International Nuclear Information System (INIS)

    Ariyoshi, Masahiko; Matsumoto, Fujio; Matsumoto, Koji; Kinugasa, Kunihiko; Nara, Yoshihiko; Otama, Kiyomaro; Mikami, Takao

    1998-01-01

    The present invention provides a device for and a method of directly driving control rods of an FBR type reactor linearly by a cylinder type linear motor while having a driving shaft as an electric conductor. Namely, a linear induction motor drives a driving shaft connected with a control rod and vertically moving the control rod by electromagnetic force as an electric conductor. The position of the control rod is detected by a position detector. The driving shaft is hung by a wire by way of an electromagnet which is attachably/detachably held. With such a constitution, the driving shaft connected with the control rod can be vertically moved linearly, stopped or kept. Since they can be driven smoothly at a wide range speed, the responsibility and reliability of the reactor operation can be improved. In addition, since responsibility of the control rod operation is high, scram can be conducted by the linear motor. Since the driving mechanism can be simplified, maintenance and inspection operation can be mitigated. (I.S.)

  8. Growth, Segregation and Displacement Mechanisms in the Peri-urban of Quito

    Directory of Open Access Journals (Sweden)

    Gustavo Durán

    2016-09-01

    Full Text Available This paper seeks a qualitative approach to the urban periphery of Quito with the purpose of investigating, in the context of the expansion process of the city, the possible effects of real-estate actions in the socio-spatial transformations of the traditional inhabitants of those areas where the urbanizing process intensified. Through the ethnographic method, sample contextualization techniques, passive observation processes and key actor interviews were used. From identifying the transformations in the urban landscapes and the characterization of the most relevant processes and actors within these transformations, it was possible to build empirical evidence on displacement processes and generation of conflicts as a result of urban development in the periphery in Quito.

  9. Probing the Type I Seesaw mechanism with displaced vertices at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gago, Alberto M. [Pontificia Universidad Catolica del Peru, Seccion Fisica, Departamento de Ciencias, Lima (Peru); Hernandez, Pilar [CSIC-Universitat de Valencia, Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Jones-Perez, Joel [Pontificia Universidad Catolica del Peru, Seccion Fisica, Departamento de Ciencias, Lima (Peru); CSIC-Universitat de Valencia, Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Losada, Marta; Moreno Briceno, Alexander [Universidad Antonio Narino, Centro de Investigaciones en Ciencias Basicas y Aplicadas, Bogota, D. C. (Colombia)

    2015-10-15

    The observation of Higgs decays into heavy neutrinos would be strong evidence for new physics associated to neutrino masses. In this work we propose a search for such decays within the Type I Seesaw model in the few-GeV mass range via displaced vertices. Using 300 fb{sup -1} of integrated luminosity, at 13 TeV, we explore the region of parameter space where such decays are measurable. We show that, after imposing pseudorapidity cuts, there still exists a region where the number of events is larger than O(10). We also find that conventional triggers can greatly limit the sensitivity of our signal, so we display several relevant kinematical distributions which might aid in the optimization of a dedicated trigger selection. (orig.)

  10. Conceptual Design on Primary Control Rod Drive Mechanism of a Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Koo, Gyeong Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    This paper describes the key concept of the drive mechanism, and suggests a required motor power and reducer gears to meet the functional design requirements, and a seismic response analysis of CRDM housing is performed to check its structural integrity. An AC servo motor is selected as a CRA driving power because it uses permanent magnets and is brushless type while DC motor needs a brush and a coil rotates. The control shim motor size is constrained by a housing diameter of 250mm. The driving system has several design requirements. To calculate the motor power, the drive shaft torque is needed. One part of the drive shaft has a lead screw, driving by a ball-nut. The ball screw driver torque (Tr) is calculated by some equations as follow; A servo motor with a nominal power of 100W, a nominal torque of 0.32 N-m (max. 0.48N-m) is selected considering a safety margin. Its diameter is about 50mm. The fast drive-in motor needs a strong power to insert enforcedly the stuck CRA into core within a required time. The motor sizes are calculated by the same procedure. The diameters are in the range of 80mm to 110mm by the insertion time (10 ∼ 24 seconds). The prototype Gen-IV SFR (sodium-cooled Fast Reactor) is of 150MWe capacity. The reactor has six primary control rod assemblies(CRAs). The primary control rod is used for power control, burn-up compensation and reactor shutdown in response to demands from the plant control or protection systems. The control rod drive mechanism (CRDM) consists of the drive motor assembly, the driveline, and its housing. The driveline consists of three concentric members of a drive shaft, a tension tube, and a position indicator rod, and it connects the drive motor assembly to the CRA. Main issue is that these many driving parts shall be enclosed within a limited housing diameter because the available pitch of CRDMs is limited by 300mm.

  11. Finite element analysis of ROPS for mechanical driving dump truck cab

    Science.gov (United States)

    Wang, Yong; Xie, Heping; Fang, Yuanbin; Feng, Handui; Dong, Lei

    2018-02-01

    For roll-over protective structures (ROPS) in a mechanical driving dump truck cab, it simulates the lateral, vertical and longitudinal loads of ROPS. It obtains stress and deformation of the cab that occurs to roll. For the relative weak position of ROPS in the cab, the structure of the cab is improved and verified according to the ISO 3164: 1995. The results show that the established finite element model can effectively predict the deformation and stress distribution of ROPS, and optimize the weak structure of the cab, which has important guiding significance for structural design of the cab and ROPS optimization of the mechanical driving dump truck cab.

  12. Electromagnetic device of linear displacement

    International Nuclear Information System (INIS)

    Savary, F.; Le Saulnier, G.

    1986-01-01

    The device moves a rod integral with a nuclear reactor control element. It has a grab for the rod operated by a mobil pole drive by a coil carried by a surrounding sealed casing, a second grab with fixed and mobile poles with facing surfaces shaped to limit the variation of magnetic force with distance between them, and a plunger driven by a coil to bear against another mobile pole moved by a coil. The invention proposes a device ensuring a displacement while the impact forces at the different level of the mechanism are reduced [fr

  13. On current drive by Ohkawa mechanism of electron cyclotron wave in large inverse aspect ratio tokamaks

    Science.gov (United States)

    Zheng, Pingwei; Gong, Xueyu; Lu, Xingqiang; He, Lihua; Cao, Jingjia; Huang, Qianhong; Deng, Sheng

    2018-03-01

    A localized and efficient current drive method in the outer-half region of the tokamak with a large inverse aspect ratio is proposed via the Ohkawa mechanism of electron cyclotron (EC) waves. Further off-axis Ohkawa current drive (OKCD) via EC waves was investigated in high electron beta β e HL-2M-like tokamaks with a large inverse aspect ratio, and in EAST-like tokamaks with a low inverse aspect ratio. OKCD can be driven efficiently, and the driven current profile is spatially localized in the radial region, ranging from 0.62 to 0.85, where the large fraction of trapped electrons provides an excellent advantage for OKCD. Furthermore, the current drive efficiency increases with an increase in minor radius, and then drops when the minor radius beyond a certain value. The effect of trapped electrons greatly enhances the current driving capability of the OKCD mechanism. The highest current drive efficiency can reach 0.183 by adjusting the steering mirror to change the toroidal and poloidal incident angle, and the total driven current by OKCD can reach 20–32 kA MW‑1 in HL-2M-like tokamaks. The current drive is less efficient for the EAST-like scenario due to the lower inverse aspect ratio. The results show that OKCD may be a valuable alternative current drive method in large inverse aspect ratio tokamaks, and the potential capabilities of OKCD can be used to suppress some important magnetohydrodynamics instabilities in the far off-axis region.

  14. The effect of rigid taping with tension on mechanical displacement of the skin and change in pain perception.

    Science.gov (United States)

    Chen, Shu-Mei; Lo, Sing Kai; Cook, Jill

    2018-04-01

    To investigate the effect of rigid taping that induces mechanical displacement of the skin on pain perception. Single group experiment design with repeated measures. Twenty-three active healthy volunteers (12 men and 11 women) participated in the study. All participants received three different taping procedures: no tape, taping with tension, and taping without tension. The order of three taping conditions was randomised. Skin displacement was measured during taping with tension. A pressure algometer was used to measure the level of pain perception once before taping, and again after each taping condition, in one testing session. The participants were blind to the values of their pressure pain threshold (PPT) during the experimental period. The mean±SD skin displacement in the condition of taping with tension was 2.58±0.49cm. There were significant differences in PPT between taping with tension and taping without tension (mean difference (mean diff)±standard error (SE) 36.43±4.22kPa, p=0.000) and no tape (mean diff±SE 44.31±3.13kPa, p=0.000). No significant difference in PPT between no tape and taping without tension was found (mean diff±SE 7.88±2.83kPa, p=0.067). Taping with tension increases the threshold of pressure pain perception. Therefore, stretch and compression caused by rigid taping with tension could disturb the nociceptive signal transmission and alter pain perception. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. Nitrous acid (HONO) nocturnal surface deposition and daytime acid displacement: An alternative mechanism contributing to the unknown daytime HONO source

    Science.gov (United States)

    Murphy, J. G.; VandenBoer, T. C.; Roberts, J. M.; Young, C. J.; Brown, S. S.; Markovic, M. Z.; Talukdar, R. K.

    2012-12-01

    Measurements of HONO were made during two intensive field campaigns: NACHTT 2011 in Erie, CO and CalNex 2010 in Bakersfield, CA. These field data and results from a flow tube study provide a new perspective on the interactions of HONO with ground surfaces. Integrated atmospheric column measurements of HONO and NO2 during NACHTT provided clear evidence that the ground surface dominates HONO production and loss at night. Simultaneous measurements of the gas and particle phases made by an Ambient Ion Monitor - Ion Chromatography (AIM-IC) system during CalNex demonstrated the potential for reactive uptake of HONO on mineral dust/soil as a nocturnal sink. Similarly, the potential for nitrite salts to react with strong acids, displacing HONO during the day was suggested by this dataset. Lab study results confirmed that HONO reacts irreversibly with carbonate salts and real soil extracts. Relative humidity-dependent reactive uptake coefficients were derived. Subsequent release of HONO by displacement reactions with HNO3 and HCl was also demonstrated. Together, these field and lab studies contribute to a new picture of HONO surface interactions by providing i) a more explicit description of the nocturnal HONO sink that also is a surface reservoir and ii) a new mechanism for daytime HONO formation that does not require NO2.

  16. Aging considerations for PWR [pressurized water reactor] control rod drive mechanisms and reactor internals

    International Nuclear Information System (INIS)

    Ware, A.G.

    1988-01-01

    This paper describes age-related degradation mechanisms affecting life extension of pressurized water reactor control rod drive mechanisms and reactor internals. The major sources of age-related degradation for control rod drive mechanisms are thermal transients such as plant heatups and cooldowns, latchings and unlatchings, long-term aging effects on electrical insulation, and the high temperature corrosive environment. Flow induced loads, the high-temperature corrosive environment, radiation exposure, and high tensile stresses in bolts all contribute to aging related degradation of reactor internals. Another problem has been wear and fretting of instrument guide tubes. The paper also discusses age-related failures that have occurred to date in pressurized water reactors

  17. Holographic velocimetry using object-conjugate reconstruction (OCR): a new approach for simultaneous, 3D displacement measurement in fluid and solid mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Barnhart, D.H.; Halliwell, N.A.; Coupland, J.M. [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Chan, V.S.S. [Department of Mechanical and Manufacturing Engineering, Trinity College, Dublin 2 (Ireland)

    2002-12-01

    This paper reports on a new form of holographic metrology that enables displacement measurement in both fluid and solid mechanics simultaneously. In such instances, existing holographic methods for displacement measurement would require the application of multiple techniques in a hybrid fashion. Known as object-conjugate reconstruction (OCR), our new approach unifies the disciplines of holographic velocimetry and holographic interferometry. Using complex correlation processing, it provides a sub-wavelength resolution for all three components of displacement and enables automated data extraction at selected points throughout a volume in space. (orig.)

  18. A displacement-based finite element formulation for incompressible and nearly-incompressible cardiac mechanics.

    Science.gov (United States)

    Hadjicharalambous, Myrianthi; Lee, Jack; Smith, Nicolas P; Nordsletten, David A

    2014-06-01

    The Lagrange Multiplier (LM) and penalty methods are commonly used to enforce incompressibility and compressibility in models of cardiac mechanics. In this paper we show how both formulations may be equivalently thought of as a weakly penalized system derived from the statically condensed Perturbed Lagrangian formulation, which may be directly discretized maintaining the simplicity of penalty formulations with the convergence characteristics of LM techniques. A modified Shamanskii-Newton-Raphson scheme is introduced to enhance the nonlinear convergence of the weakly penalized system and, exploiting its equivalence, modifications are developed for the penalty form. Focusing on accuracy, we proceed to study the convergence behavior of these approaches using different interpolation schemes for both a simple test problem and more complex models of cardiac mechanics. Our results illustrate the well-known influence of locking phenomena on the penalty approach (particularly for lower order schemes) and its effect on accuracy for whole-cycle mechanics. Additionally, we verify that direct discretization of the weakly penalized form produces similar convergence behavior to mixed formulations while avoiding the use of an additional variable. Combining a simple structure which allows the solution of computationally challenging problems with good convergence characteristics, the weakly penalized form provides an accurate and efficient alternative to incompressibility and compressibility in cardiac mechanics.

  19. Method of controlling moving-coil type control rod driving mechanisms

    International Nuclear Information System (INIS)

    Hosoya, Kazuya; Kanazawa, Takashi; Matsuzaki, Tokunori.

    1986-01-01

    Purpose: To enable solenoid plungers to sufficiently follow after abrupt changes of moving speed of moving-coils in nuclear reactors. Method: In a control circuit for moving-coil type control rod driving mechanisms of nuclear reactors, the velocity of a driving device for the moving-coils is detected by a velocity detector to control the velocity change of exciting currents in the coils depending on a velocity instruction signal. Since the velocity change of the coil exciting current varies depending on the change in the velocity instruction signal, the solenoid plunger can smoothly follow after the moving coils electromagnetically coupled therewith, and the deviation between the moving-coils and the solenoid plunger, that is, the driving axis can be minimized. Accordingly, smooth reactor control can be attained. (Takahashi, M.)

  20. Gravity-Off-loading System for Large-Displacement Ground Testing of Spacecraft Mechanisms

    Science.gov (United States)

    Han, Olyvia; Kienholz, David; Janzen, Paul; Kidney, Scott

    2010-01-01

    Gravity-off-loading of deployable spacecraft mechanisms during ground testing is a long-standing problem. Deployable structures which are usually too weak to support their own weight under gravity require a means of gravity-off-loading as they unfurl. Conventional solutions to this problem have been helium-filled balloons or mechanical pulley/counterweight systems. These approaches, however, suffer from the deleterious effects of added inertia or friction forces. The changing form factor of the deployable structure itself and the need to track the trajectory of the center of gravity also pose a challenge to these conventional technologies. This paper presents a novel testing apparatus for high-fidelity zero-gravity simulation for special application to deployable space structures such as solar arrays, magnetometer booms, and robotic arms in class 100,000 clean room environments

  1. Accessing thermo-mechanical properties of semiconductors using a pump-probe surface displacement method

    Science.gov (United States)

    González-Borrero, P. P.; Lukasievicz, G. V. B.; Zanuto, V. S.; Astrath, N. G. C.; Malacarne, L. C.

    2017-05-01

    Description of the physical mechanism leading to laser induced thermal and electronic effects in semiconductors is crucial in both basic research and technological applications. In this paper, we present a thermal mirror technique to study the thermo-mechanical properties of semiconductors. A detailed theoretical investigation is presented, and the dominant effects are described in terms of the physical properties of the material. The effect of heat coupling between the sample and the surrounding fluid was taken into account and considerations on the time and spatial approximations to the photogenerated carriers profile were used to simplify the theoretical model. These approximations were then compared to numerical models and the results hold for high recombination rate semiconductors. Experiments were performed to validate the theoretical model, and the thermal diffusivity and photogenerated heat in the sample were determined. The values obtained for these properties were found to be in good agreement with literature.

  2. Mechanical characterization and force-displacement hysteretic curves from in-plane cyclic tests on strong masonry infills

    Directory of Open Access Journals (Sweden)

    Paolo Morandi

    2018-02-01

    Full Text Available This article contains information related to a recent study “Performance-based interpretation of in-plane cyclic tests on RC frames with strong masonry infills” (Morandi et al., 2017 [1]. Motivated by the necessity to improve the knowledge of the in-plane seismic response of rigid strong masonry infills, a wide experimental campaign based on in-plane cyclic tests on full-scale RC infilled frame specimens, supplemented with a complete characterization of the materials, has been conducted at the laboratory of the Department of Civil Engineering and Architecture of the University of Pavia. The masonry is constituted by vertically perforated 35 cm thick clay units with tongue and groove and dry head-joints and general-purpose mortar bed-joints. The paper reports the results of the mechanical characterization and of the force-displacement hysteretic curves from the in-plane cyclic tests.

  3. Mechanical characterization and force-displacement hysteretic curves from in-plane cyclic tests on strong masonry infills.

    Science.gov (United States)

    Morandi, Paolo; Hak, Sanja; Magenes, Guido

    2018-02-01

    This article contains information related to a recent study "Performance-based interpretation of in-plane cyclic tests on RC frames with strong masonry infills" (Morandi et al., 2017 [1]). Motivated by the necessity to improve the knowledge of the in-plane seismic response of rigid strong masonry infills, a wide experimental campaign based on in-plane cyclic tests on full-scale RC infilled frame specimens, supplemented with a complete characterization of the materials, has been conducted at the laboratory of the Department of Civil Engineering and Architecture of the University of Pavia. The masonry is constituted by vertically perforated 35 cm thick clay units with tongue and groove and dry head-joints and general-purpose mortar bed-joints. The paper reports the results of the mechanical characterization and of the force-displacement hysteretic curves from the in-plane cyclic tests.

  4. Detection and suppression for mechanical resonance in hard disk drives with built-in piezoelectric sensors

    Science.gov (United States)

    Gao, Peng; Lou, Yaolong; Okada, Kanzo

    2002-07-01

    Many components in hard disk drives (HDDs), when in operation, are subjected to vibration due to out of balance of rotating components, inertial impacts under servo driving and dynamic interactions between components. These vibrations have been found to have significant effect upon the servo performance of drive systems. In order to improve the servo performance by reducing the effect of mechanical resonance in HDDs, this paper seeks to detect and suppress mechanical resonance of the head actuator using smart sensors and multi-sensing control techniques. In this regard, sensitive and miniature piezoelectric elements from the polymer-based piezoelectric materials PVDF (polyvinylindin fluoride) or the ceramic-based piezoelectric materials PZT 9lead zircornate titanate) are built in the head actuator for sensing the mechanical vibration. In the experiment, the multi-sensing signals by the piezoelectric sensors and the laser Doppler vibrometer (LDV) are transferred into a voice coil motor (VCM) through a feedback controller so as to actively suppress structural resonance. Numerical simulation and experimental results indicate that the piezoelectric sensors provide an effective way in monitoring the HDD actuator resonance, and the active vibration control strategy is capable of suppressing main mechanical resonance in the head actuator effectively.

  5. Driving mechanism and sources of groundwater nitrate contamination in the rapidly urbanized region of south China

    Science.gov (United States)

    Zhang, Qianqian; Sun, Jichao; Liu, Jingtao; Huang, Guanxing; Lu, Chuan; Zhang, Yuxi

    2015-11-01

    Nitrate contamination of groundwater has become an environmental problem of widespread concern in China. We collected 899 groundwater samples from a rapidly urbanized area, in order to identify the main sources and driving mechanisms of groundwater nitrate contamination. The results showed that the land use has a significant effect on groundwater nitrate concentration (P population growth. This study revealed that domestic wastewater and industrial wastewater were the main sources of groundwater nitrate pollution. Therefore, the priority method for relieving groundwater nitrate contamination is to control the random discharge of domestic and industrial wastewater in regions undergoing rapid urbanization. Capsule abstract. The main driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth.

  6. ANALYSIS OF THE MECHANICAL STRENGTH OF A DRIVING MECHANISM CALLED SHOCK

    Directory of Open Access Journals (Sweden)

    Dan ILINCIOIU

    2015-05-01

    Full Text Available It evaluates the maximum static and dynamic stresses produced in the elements of a quadrilateral mechanism transporting a vehicle in the storage in an urban park. Determine multiplier shock hazard if the mechanism freezes and increases mechanical stress.

  7. Design of diverse safety rod and its drive mechanism of PFBR

    International Nuclear Information System (INIS)

    Vijayashree, R.; Govindarajan, S.; Chetal, S.C.

    1997-01-01

    In Prototype Fast Breeder Reactor (PFBR), there are two types of absorber rods for control and shutdown of the reactor in the event of any abnormal event. They are: (i) Control and Safety Rod (CSR) and (ii) the Diverse Safety Rod (DSR). Of these, the former (CSR) caters to the control function of the reactor during normal operating conditions and to the shutdown during abnormal situations. The DSR, on the other hand is meant essentially for the reactor shutdown to take care of any abnormal transient. It is rather important to note that functionally the DSR is independent of CSR in the sense, that it can bring the reactor to a cold shutdown state and maintain it even under the hypothetical condition of the failure of CSR. From the design point of view, this stipulates a failure probability of less than 10 -4 per demand. The DSR is normally parked above the core by the Diverse Safety Rod Drive Mechanism (DSRDM). On receiving a scram signal it gets released from the holding electromagnet and falls under the gravity into the core. Diverse features are incorporated both in the absorber rods and in the drive mechanisms to avoid common mode failures. This paper discusses the salient features of DSR and DSRDM. A brief account of detailed design, analysis and development of two important subassemblies viz. electromagnet and sodium dash pot is also presented. In addition, a brief comparison between CSR and DSR including their drive mechanisms is also provided. (author)

  8. Holonomic planar motion from non-holonomic driving mechanisms: the front-point method

    Science.gov (United States)

    Temizer, Selim; Pack Kaelbling, Leslie

    2002-02-01

    There are many methods that address navigation and path planning for mobile robots with non-holonomic motion constraints using clever techniques and exploiting application-specific data, but it is always better not to have any such constraints at all. In this document we re-examine the capabilities of some popular driving mechanisms from a different perspective and describe a method to obtain holonomic motion using those mechanisms. The main idea is to not concentrate on the center of the driving mechanism (which is the usual choice) as the reference point for our calculations, but to select another point whose motion in the x-y plane is not constrained in any direction, and which is also a logical and useful substitute for the center. In addition to the derivation of the forward and inverse kinematics equations for the new reference point, we also explain how to further simplify the design of a controller which uses the described method to compute motion commands for the robot. In order to illustrate the ideas, we present graphs that were plotted using the actual parameter values for a synchronous-drive research robot.

  9. In situ characterization of wettability alteration and displacement mechanisms governing recovery enhancement due to low-salinity waterflooding

    Science.gov (United States)

    Khishvand, M.; Alizadeh, A. H.; Oraki Kohshour, I.; Piri, M.; Prasad, R. S.

    2017-05-01

    A series of micro-scale core-flooding experiments were performed on reservoir core samples at elevated temperature and pressure conditions to develop better insights into wettability alteration and pore-scale displacement mechanisms taking place during low-salinity waterflooding (LSWF). Two individual miniature core samples were cut from a preserved reservoir whole core, saturated to establish initial reservoir fluid saturation conditions, and subsequently waterflooded with low-salinity and high-salinity brines. A third miniature sister core sample was also cut, solvent-cleaned, and subjected to a dynamic wettability restoration process (to reestablish native state wettability) and then a low-salinity waterflood. All samples were imaged during the experiments using a micro-CT scanner to obtain fluid occupancy maps and measure in situ oil-water contact angles. The results of the experiments performed on the preserved core samples show a significantly improved performance of low-salinity waterflooding compared to that of high-salinity waterflooding (HSWF). Pore-scale contact angle measurements provide direct evidence of wettability alteration from weakly oil-wet toward weakly water-wet conditions during LSWF, whereas contact angles measured during HSWF remain unchanged. We believe that the reduction in oil-water contact angles toward increased water-wetness lowers the threshold water pressure needed to displace oil from some medium-sized pore elements. Contact angles measured during the dynamic wettability restoration process show an equilibrium wettability state very similar to the initial one observed in the preserved samples. This indicates that drilling fluid contaminants had a negligible effect on the reservoir rock wettability. The experimental results also reveal similarities between saturation trends for the preserved-LSWF and restored-LSWF tests.

  10. Dynamic Simulation Research on Chain Drive Mechanism of Corn Seeder Based on ADAMS

    Science.gov (United States)

    Wang, Y. B.; Jia, H. P.

    2017-12-01

    In order to reduce the damage to the chain and improve the seeding quality of the seeding machine, the corn seeder has the characteristics of the seeding quality and some technical indexes in the work of the corn seeding machine. The dynamic analysis of the chain drive mechanism is carried out by using the dynamic virtual prototype. In this paper, the speed of the corn planter is 5km/h, and the speed of the simulated knuckle is 0.1~0.9s. The velocity is 0.12m/s, which is equal to the chain speed when the seeder is running normally. Of the dynamic simulation of the movement and the actual situation is basically consistent with the apparent speed of the drive wheel has changed the acceleration and additional dynamic load, the chain drive has a very serious damage, and the maximum load value of 47.28N, in order to reduce the damage to the chain, As far as possible so that the sowing machine in the work to maintain a reasonable uniform speed, to avoid a greater acceleration, the corn sowing machine drive the design of a certain reference.

  11. Development of a 3-D simulation analysis system for PWR control rod drive mechanism

    International Nuclear Information System (INIS)

    Tanaka, Akio; Futahashi, Kensuke; Takanabe, Kiyoshi; Kurimura, Chikara; Kato, Jungo; Hara, Hidekiyo

    2008-01-01

    A 3-D virtual analysis system to analyze the motion of control rod drive mechanism (CRDM) was developed. The analysis system consists of a 3-D model established as per the actual dimensions and interfaces of CRDM parts and a routine to calculate the forces acting on the mechanism, and was verified by mock-up test using the same equipment as the actual product. The analysis system is useful for functional evaluation in maintenance or to factor out root causes in the case of malfunction of CRDM

  12. The atomistic mechanism for Sb segregation and As displacement of Sb in InSb(001) surfaces

    Science.gov (United States)

    Anderson, Evan M.; Millunchick, Joanna M.

    2018-01-01

    Interfacial broadening occurs in mixed-anion alloy heterostructures such as InAs/InAsSb due to both Sb-segregation and As-for-Sb exchange. In order to determine the atomistic mechanisms for these processes, we conduct ab initio calculations coupled with a cluster expansion formalism to determine the surface reconstructions of the pure and As-exposed InSb(001) surfaces. This approach provides a predicted phase diagram for pure InSb that is in better agreement with experiments. Namely, the α2(2 × 4) and α3c(4 × 4) structures are ultimately stable at 0K, but the α(4 × 3) and α2c(2 × 6) are within 1 meV/Å2. Exposure of the InSb(001) surface to As results in the As atoms infiltrating into the crystal and displacing subsurface Sb, thus providing the atomistic mechanisms for experimental observations of the As-for-Sb exchange reaction and Sb segregation. Experiments show that the widely reported A-(1 × 3) reconstruction is actually comprised of multiple reconstructions, which is consistent with the prediction of several nearly stable possible reconstructions.

  13. Displacement ventilation

    DEFF Research Database (Denmark)

    Kosonen, Risto; Melikov, Arsen Krikor; Mundt, Elisabeth

    The aim of this Guidebook is to give the state-of-the art knowledge of the displacement ventilation technology, and to simplify and improve the practical design procedure. The Guidebook discusses methods of total volume ventilation by mixing ventilation and displacement ventilation and it gives...... insights of the performance of the displacement ventilation. It also shows practical case studies in some typical applications and the latest research findings to create good local micro-climatic conditions....

  14. Drive mechanism for the shuttle orbiter/external tank propellant disconnect

    Science.gov (United States)

    Thomas, E.; Wilders, R.; Ulanovsky, J.

    1981-01-01

    The space shuttle design required development of a large, 0.43 m nominal diameter separable disconnect for the liquid hydrogen and liquid oxygen propellant lines at the orbiter to external tank interface. The disconnect provides for shutoff of the propellant flow area by simultaneous action of two rotary flapper valves (orbiter and external tank) prior to disconnect separation. In the case of pneumatic system failure, the rotary flapper valves are closed automatically through mechanical interlocking linkage during disconnect separation. The mechanism must meet requirements while accommodating changes in bearing clearances and linkage geometry over a wide temperature range from ambient to 20.37 K. The mechanical design of the separable disconnect, kinematics of the drive mechanism, and the analysis and test methods used to verify proper operation and qualification for the space shuttle dynamic environments are presented.

  15. Mechanical stability of a locked step-plate versus single compression screw fixation for medial displacement calcaneal osteotomy.

    Science.gov (United States)

    Konan, Sujith; Meswania, Jay; Blunn, Gordon W; Madhav, Rohit T; Oddy, Michael J

    2012-08-01

    Reconstruction of a flatfoot commonly involves a calcaneal Medial Displacement Osteotomy (MDO) to correct hindfoot valgus in combination with soft tissue procedures. We compared fixation of an MDO using either a single, large cannulated screw versus a locking step-plate in load to failure in a cadaveric model. Eight matched pairs of cadaveric limbs were loaded using a mechanical testing rig. Two pairs served as non-operated controls. The remaining paired limbs underwent a 10-mm MDO stabilized either with a single 7-mm screw or a step-plate with four locking screws. One pair was used as a pilot study and the remaining five pairs were loaded up to 4500 N to failure. In the five pairs loaded to failure, the median (with 95% CI) maximum force were 1779 N (1099-2312) and 826 N (288-1607) for the plate and screw, respectively (p = 0.043). With single screw fixation, the tuberosity fragment consistently failed by rotation and angulation into varus. With plate fixation, failure occurred as the screws cut through the internal surfaces of the tuberosity and body with no failure at the screw-plate interface. In this cadaveric model, a locked step-plate supported a significantly higher maximum force than a single large cannulated screw. The magnitude of the load supported by the locking step-plate suggests that allowing early weightbearing post-operation may be safe in clinical practice before union of the osteotomy.

  16. Simultaneous electrical and mechanical resonance drive for large signal amplification of micro resonators

    KAUST Repository

    Hasan, M. H.

    2018-01-12

    Achieving large signal-noise ratio using low levels of excitation signal is key requirement for practical applications of micro and nano electromechanical resonators. In this work, we introduce the double electromechanical resonance drive concept to achieve an order-of-magnitude dynamic signal amplification in micro resonators. The concept relies on simultaneously activating the micro-resonator mechanical and electrical resonance frequencies. We report an input voltage amplification up to 15 times for a micro-resonator when its electrical resonance is tuned to match the mechanical resonance that leads to dynamic signal amplification in air (Quality factor enhancement). Furthermore, using a multi-frequency excitation technique, input voltage and vibrational amplification of up to 30 times were shown for the same micro-resonator while relaxing the need to match its mechanical and electrical resonances.

  17. Stress and fatigue analysis for lower joint of control rod drive mechanisms seal house

    International Nuclear Information System (INIS)

    Shao Xuejiao; Zhang Liping; Du Juan; Xie Hai

    2013-01-01

    Two kinds of seal houses for control rod drive mechanisms which have different thickness of the lower seal ring was analyzed for its stress and fatigue by finite element method. In the fatigue computation, all the transitions were grouped into several groups, and then the elastoplastic strain correction factor was modified by analyzing thermal and mechanical load separately referring the rules of RCC-M 2002. The results show that the structure with thicker seal ring behaves more safely than the other one except in the second condition. Meanwhile, the amplify of the primary and secondary stress as well as fatigue usage factor can be reduced by regrouping the transients. The precision of fatigue usage factor can be elevated using modified K e when the amplify of the primary and secondary stress is large to some extent produced by both thermal and mechanical loads. (authors)

  18. Intramolecular energy transfer and the driving mechanisms for large-amplitude collective motions of clusters

    Science.gov (United States)

    Yanao, Tomohiro; Koon, Wang Sang; Marsden, Jerrold E.

    2009-04-01

    This paper uncovers novel and specific dynamical mechanisms that initiate large-amplitude collective motions in polyatomic molecules. These mechanisms are understood in terms of intramolecular energy transfer between modes and driving forces. Structural transition dynamics of a six-atom cluster between a symmetric and an elongated isomer is highlighted as an illustrative example of what is a general message. First, we introduce a general method of hyperspherical mode analysis to analyze the energy transfer among internal modes of polyatomic molecules. In this method, the (3n-6) internal modes of an n-atom molecule are classified generally into three coarse level gyration-radius modes, three fine level twisting modes, and (3n-12) fine level shearing modes. We show that a large amount of kinetic energy flows into the gyration-radius modes when the cluster undergoes structural transitions by changing its mass distribution. Based on this fact, we construct a reactive mode as a linear combination of the three gyration-radius modes. It is shown that before the reactive mode acquires a large amount of kinetic energy, activation or inactivation of the twisting modes, depending on the geometry of the isomer, plays crucial roles for the onset of a structural transition. Specifically, in a symmetric isomer with a spherical mass distribution, activation of specific twisting modes drives the structural transition into an elongated isomer by inducing a strong internal centrifugal force, which has the effect of elongating the mass distribution of the system. On the other hand, in an elongated isomer, inactivation of specific twisting modes initiates the structural transition into a symmetric isomer with lower potential energy by suppressing the elongation effect of the internal centrifugal force and making the effects of the potential force dominant. This driving mechanism for reactions as well as the present method of hyperspherical mode analysis should be widely applicable to

  19. Nonlinear Dynamics Response of a Planar Mechanism with Two Driving Links and Prismatic Pair Clearance

    Directory of Open Access Journals (Sweden)

    Lijuan Wu

    2017-01-01

    Full Text Available The influence of the joint clearance on the dynamic response of a planar mechanism with two driving links and prismatic pair clearance is investigated under variable input speeds of the system. The simulation model was built with a nonlinear impact model. The normal contact force is characterized by Hertz contact theory and an energy dissipation term. A tangential friction force is involved in the simulation model based on Coulomb’s friction law. The simulation results indicate that the largest Lyapunov exponents are dependent on the clearance size and the input speed.

  20. Driving and damping mechanisms in hybrid pressure-gravity modes pulsators

    Energy Technology Data Exchange (ETDEWEB)

    Dupret, M A [Observatoire de Paris, LESIA, CNRS UMR 8109, 5 place J. Janssen, 92195 Meudon (France); Miglio, A; Montalban, J; Noels, A [Institut d' Astrophysique et Geophysique, Universite de Liege (Belgium); Grigahcene, A [CRAAG - Algiers Observatory BP 63 Bouzareah 16340, Algiers (Algeria)], E-mail: MA.dupret@obspm.fr

    2008-10-15

    We study the energetic aspects of hybrid pressure-gravity modes pulsations. The case of hybrid {beta} Cephei-SPB pulsators is considered with special attention. In addition to the already known sensitivity of the driving mechanism to the heavy elements mixture (mainly the iron abundance), we show that the characteristics of the propagation and evanescent regions play also a major role, determining the extension of the stable gap in the frequency domain between the unstable low order pressure and high order gravity modes. Finally, we consider the case of hybrid {delta} Sct-{gamma} Dor pulsators.

  1. The construction design of ball bearings used in the control rod driving mechanisms of PWRs

    International Nuclear Information System (INIS)

    Leng Chengmu; Huang Chongming; Chen Jianting.

    1986-01-01

    According to the operation conditions of ball bearings used in the control rod driving mechanisms of PWRs, this paper has analysed and discussed the problems that must be taken into account in the construction design of this ball bearing. It includes: a discussion about the reasonable selection of construction parameters of the bearing, deduction of the relationship between bearing clearance and contact angle, and the emphasis on the significance of assembling accuracy and torque measurement in the assurance of operational performance of the bearings. These experiences may be somewhat valuable for the design and application of this kind of ball bearing

  2. Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    Displacement ventilation is an interesting new type of air distribution principle which should be considered in connection with design of comfort ventilation in both smal1 and large spaces. Research activities on displacement ventilation are large all over the world and new knowledge of design...... methods appears continuously. This book gives an easy introduction to the basis of displacement ventilation and the chapters are written in the order which is used in a design procedure. The main text is extended by five appendices which show some of the new research activities taking place at Aalborg...

  3. Displacement regularity of the coal ribs by both sides of a fully mechanized coal face with caving in gently inclined extra thick seam

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z.; Cao, S.; Li, H.; Liu, S. (China University of Mining and Technology (China))

    1993-09-01

    Based on field observations, the displacement regularly of coal ribs by both sides of a fully mechanized coal face with top coal caving in gently inclined extra thick seam and its effective factors are analyzed. The displacement is viewed to be affected by the process of coal extraction, supports shifting, top coal caving and roof movement. Along with the advancement of face, the displacement of coal ribs may be divided into multiple stages. The maximum displacement rate of both ribs near the top coal caving line is up to 12-20 mm/d, while the average in the gob is 10-14 mm/d. For the horizontal displacement rate of the top coal along the dip, there is a dividing line at 4m on the uphill side of the lower gateway. In front of face the horizontal displacement rate of top coal is higher by the gateway side than by the face side, while behind the face line, it is higher by the gob side than by the rob side. The displacement by the uphill side is larger than that by the downhill side. Along the dip, the caving angles of the top coal by both uphill and downhill sides are respectively 66[degree] and 64[degree]. They are so small that it is unfavourable for top coal caving. If a roadway was to be driven in the previous gob, it should be done till the surrounding rocks have stopped moving and the stress distribution is steady, and the roadway should be located in the stress relief zone. 6 figs., 3 tabs.

  4. INVESTIGATION OF MECHANICAL STRESSES IN THE DRIVE SHAFT OF MV VACUUM CIRCUIT BREAKER

    Directory of Open Access Journals (Sweden)

    E. I. Baida

    2017-03-01

    Full Text Available Introduction. In the last 10-15 years a dominant position in the market of medium voltage circuit breakers, vacuum circuit breakers have taken in which as an actuator mono- or bistable actuators with permanent magnets are used. Such circuit breakers are characterized by simplicity of design, high reliability, require preventive maintenance for many years. Development, research and improvement of vacuum circuit breakers are carried out at the Department for Electrical Apparatus, National Technical University «Kharkiv Polytechnic Institute». While working on the circuit breakers, developers have to deal with two related objectives – electrical and mechanical. This paper considers the solution of one of these problems – calculation of mechanical forces in the drive shaft of the vacuum circuit breaker in static and dynamic modes. This work was preceded by the failure of the results of measurements of the prototype circuit breakers’ contacts. Measurements have shown that these values do not match the expected values (there were less than the value of 0.8 to 1 mm. The assumption about the reasons for this discrepancy needed to be detailed checked. The results of the work done are presented in this paper. Purpose. Investigation of static and dynamic mechanical stresses and strains in the drive shaft of the vacuum circuit breaker mechanism to determine its characteristics and material selection. Methods. The investigation of mechanical processes is performed by the finite element method in the COMSOL software package. Results. We obtain the static and dynamic characteristics of the circuit breaker drive shaft: deformations, reaction forces, stresses. These characteristics made it possible to determine the actual course of the contacts, select shaft material and calculate the forces acting on the bearings. Conclusions. It is shown that the contact velocity and contact pressure are different from the theoretical value due to the deformation of the

  5. Standard guide for mechanical drive systems for remote operation in hot cell facilities

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 Intent: 1.1.1 The intent of this standard is to provide general guidelines for the design, selection, quality assurance, installation, operation, and maintenance of mechanical drive systems used in remote hot cell environments. The term mechanical drive systems used herein, encompasses all individual components used for imparting motion to equipment systems, subsystems, assemblies, and other components. It also includes complete positioning systems and individual units that provide motive power and any position indicators necessary to monitor the motion. 1.2 Applicability: 1.2.1 This standard is intended to be applicable to equipment used under one or more of the following conditions: 1.2.1.1 The materials handled or processed constitute a significant radiation hazard to man or to the environment. 1.2.1.2 The equipment will generally be used over a long-term life cycle (for example, in excess of two years), but equipment intended for use over a shorter life cycle is not excluded. 1.2.1.3 The ...

  6. Cellular and Molecular Mechanisms of REM Sleep Homeostatic Drive: A Plausible Component for Behavioral Plasticity

    Directory of Open Access Journals (Sweden)

    Subimal Datta

    2017-09-01

    Full Text Available Homeostatic regulation of REM sleep drive, as measured by an increase in the number of REM sleep transitions, plays a key role in neuronal and behavioral plasticity (i.e., learning and memory. Deficits in REM sleep homeostatic drive (RSHD are implicated in the development of many neuropsychiatric disorders. Yet, the cellular and molecular mechanisms underlying this RSHD remain to be incomplete. To further our understanding of this mechanism, the current study was performed on freely moving rats to test a hypothesis that a positive interaction between extracellular-signal-regulated kinase 1 and 2 (ERK1/2 activity and brain-derived neurotrophic factor (BDNF signaling in the pedunculopontine tegmentum (PPT is a causal factor for the development of RSHD. Behavioral results of this study demonstrated that a short period (<90 min of selective REM sleep restriction (RSR exhibited a strong RSHD. Molecular analyses revealed that this increased RSHD increased phosphorylation and activation of ERK1/2 and BDNF expression in the PPT. Additionally, pharmacological results demonstrated that the application of the ERK1/2 activation inhibitor U0126 into the PPT prevented RSHD and suppressed BDNF expression in the PPT. These results, for the first time, suggest that the positive interaction between ERK1/2 and BDNF in the PPT is a casual factor for the development of RSHD. These findings provide a novel direction in understanding how RSHD-associated specific molecular changes can facilitate neuronal plasticity and memory processing.

  7. Conceptual Design Study on Electromagnets of Control Rod Drive Mechanism of a SFR

    International Nuclear Information System (INIS)

    Lee, Jaehan; Koo, Gyeonghoi

    2013-01-01

    The prototype SFR has six primary control rod assemblies(CRAs) and three secondary shutdown assemblies. The primary control system is used for power control, burnup compensation and reactor shutdown in response to demands from the plant control or protection systems. This paper describes the design concept of primary control rod drive mechanism shortly, and performs the parametric design studies for the electromagnet device of the drive mechanism to maximize CRA gripping force. The electromagnetic core usually confines and guides the magnetic field. The major parameters influenced on the electromagnetic force are the geometry and arrangement of the electromagnet and armature for a given coil specification. A typical equation calculating the electromagnetic force for a solenoid type is represented in equation. The first one is the increasing of the flux cross section area (Α c , Α g ) in magnetic field connecting of air gap, armature and electromagnets. Secondly, the reducing of the path lengths (l c , l g ) of the armature and electromagnet makes the magnetic flux (Β) resistance to be low. An electromagnet field analyses are performed for the initial design values of the electromagnet device. The gripping force is about 3 times of CRA weight when one coil is power on. The parametric studies on air gap, core sizes configuring of the electromagnet cores are performed to maximize the electromagnetic force

  8. Summary of the control-drive-mechanism design and performance for LWBR (LWBR Development Program)

    International Nuclear Information System (INIS)

    Yarnall, F.

    1983-01-01

    Control Drive Mechanisms (CDM) are used in the Light Water Breeder reactor to position Movable Fuel Assemblies weighing in excess of one ton each for purposes of reactivity control. These mechanisms are the first of a kind designed for loads of that magnitude. This report presents a summary of the design and performance of the CDM and includes discussions of the principles of operation, unique design features, and fabrication methods of this large, high load capacity CDM. The extensive design acceptance test program and the Shippingport plant periodic testing are summrized as are lessons learned during assembly of the CDM's to the reactor. These CDM's operated successfully to control the light water breeder core at the Shippingport Station from initial criticality in August 1977 to the final shutdown in October 1982. All test and operative data were within expected bands

  9. Design of Seismic Test Rig for Control Rod Drive Mechanism of Jordan Research and Training Reactor

    International Nuclear Information System (INIS)

    Sun, Jongoh; Kim, Gyeongho; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Jong In

    2014-01-01

    The reactor assembly is submerged in a reactor pool filled with water and its reactivity is controlled by locations of four control absorber rods(CARs) inside the reactor assembly. Each CAR is driven by a stepping motor installed at the top of the reactor pool and they are connected to each other by a tie rod and an electromagnet. The CARs scram the reactor by de-energizing the electromagnet in the event of a safe shutdown earthquake(SSE). Therefore, the safety function of the control rod drive mechanism(CRDM) which consists of a drive assembly, tie rod and CARs is to drop the CAR into the core within an appropriate time in case of the SSE. As well known, the operability for complex equipment such as the CRDM during an earthquake is very hard to be demonstrated by analysis and should be verified through tests. One of them simulates the reactor assembly and the guide tube of the CAR, and the other one does the pool wall where the drive assembly is installed. In this paper, design of the latter test rig and how the test is performed are presented. Initial design of the seismic test rig and excitation table had its first natural frequency at 16.3Hz and could not represent the environment where the CRDM was installed. Therefore, experimental modal analyses were performed and an FE model for the test rig and table was obtained and tuned based on the experimental results. Using the FE model, the design of the test rig and table was modified in order to have higher natural frequency than the cutoff frequency. The goal was achieved by changing its center of gravity and the stiffness of its sliding bearings

  10. Piecewise nonlinear dynamic characteristics study of the control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao; Wang Feng

    2011-01-01

    Piecewise nonlinear dynamics of the control rod mechanism (CRDM), one of the critical components in PWR nuclear power plants, are studied for its lifting process in this paper. Firstly, equations of the electric circuit and the magnetic circuit are set up. Then based on the dynamic lifting process analysis of CRDM, its motion procedure is divided into three stages, and the coupled magnetic-electric-mechanical equation for each stage is derived. By combining the analytical solution method and the numerical simulation method, the piecewise nonlinear governing equations are solved. Finally, parameters which can illustrate the dynamic characteristics of CRDM, such as the magnetic force, the coil current, the armature displacement, the armature velocity and the acceleration are obtained and corresponding curves with the time are drawn and analyzed. The analysis results are confirmed by the test which proves the validity of our method. Work in this paper can be used for design and analysis as well as the site fault diagnosis of CRDM. (author)

  11. The evolution of mechanisms driving the stomatal response to vapor pressure deficit.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J

    2015-03-01

    Stomatal responses to vapor pressure deficit (VPD) are a principal means by which vascular land plants regulate daytime transpiration. While much work has focused on characterizing and modeling this response, there remains no consensus as to the mechanism that drives it. Explanations range from passive regulation by leaf hydration to biochemical regulation by the phytohormone abscisic acid (ABA). We monitored ABA levels, leaf gas exchange, and water status in a diversity of vascular land plants exposed to a symmetrical, mild transition in VPD. The stomata in basal lineages of vascular plants, including gymnosperms, appeared to respond passively to changes in leaf water status induced by VPD perturbation, with minimal changes in foliar ABA levels and no hysteresis in stomatal action. In contrast, foliar ABA appeared to drive the stomatal response to VPD in our angiosperm samples. Increased foliar ABA level at high VPD in angiosperm species resulted in hysteresis in the recovery of stomatal conductance; this was most pronounced in herbaceous species. Increased levels of ABA in the leaf epidermis were found to originate from sites of synthesis in other parts of the leaf rather than from the guard cells themselves. The transition from a passive regulation to ABA regulation of the stomatal response to VPD in the earliest angiosperms is likely to have had critical implications for the ecological success of this lineage. © 2015 American Society of Plant Biologists. All Rights Reserved.

  12. The Evolution of Mechanisms Driving the Stomatal Response to Vapor Pressure Deficit1[OPEN

    Science.gov (United States)

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2015-01-01

    Stomatal responses to vapor pressure deficit (VPD) are a principal means by which vascular land plants regulate daytime transpiration. While much work has focused on characterizing and modeling this response, there remains no consensus as to the mechanism that drives it. Explanations range from passive regulation by leaf hydration to biochemical regulation by the phytohormone abscisic acid (ABA). We monitored ABA levels, leaf gas exchange, and water status in a diversity of vascular land plants exposed to a symmetrical, mild transition in VPD. The stomata in basal lineages of vascular plants, including gymnosperms, appeared to respond passively to changes in leaf water status induced by VPD perturbation, with minimal changes in foliar ABA levels and no hysteresis in stomatal action. In contrast, foliar ABA appeared to drive the stomatal response to VPD in our angiosperm samples. Increased foliar ABA level at high VPD in angiosperm species resulted in hysteresis in the recovery of stomatal conductance; this was most pronounced in herbaceous species. Increased levels of ABA in the leaf epidermis were found to originate from sites of synthesis in other parts of the leaf rather than from the guard cells themselves. The transition from a passive regulation to ABA regulation of the stomatal response to VPD in the earliest angiosperms is likely to have had critical implications for the ecological success of this lineage. PMID:25637454

  13. Research on the electromagnetic structure of movable coil electromagnet drive mechanism for reactor control rod

    International Nuclear Information System (INIS)

    Zhang Jige; Yian Huijie; Wu Yuanqiang; Wu Xinxin; Yu Suyuan; He Shuyan

    2007-01-01

    The movable coil electromagnet drive mechanism (MCEDM) is a new drive scheme for the reactor control rod, and it has a simple structure, good security and reliability property, etc. MCEDM with an air cooled structure has been used in the land research reactor. In order to apply MCEDM to the mobile reactor, experimental and theoretical study on the electromagnet with an oil-water cooled structure and a single magnetic flux circuit (called the type A electro-magnet) has been completed. It is proven by the experiment and theory that the oil-water cooled structure is an excellent measure to increase the coil current of MCEDM. Moreover, a type B electromagnet with an oil-water cooled structure and double magnetic flux circuits is designed to further increase the magnetic force of MCEDM. The analysis of finite element method shows that the type B electromagnet could double the saturation current of type A electro-magnet and the magnetic force of type B electromagnet is greater than that of the type A electromagnet. Moreover, it is proven that the dynamic property of type B electromagnet is better than type A electromagnet. (author)

  14. An Optimal Design of Driving Mechanism in a 1 Degree of Freedom (d.o.f. Anthropomorphic Finger

    Directory of Open Access Journals (Sweden)

    M. Ceccarelli

    2005-01-01

    Full Text Available Mechanisms can be used in finger design to obtain suitable actuation systems and to give stiff robust behavior in grasping tasks. The design of driving mechanisms for fingers has been attached at LARM in Cassino with the aim to obtain one degree of freedom actuation for an anthropomorphic finger. The dimensional design of a finger-driving mechanism has been formulated as a multi-objective optimization problem by using evaluation criteria for fundamental characteristics regarding with finger motion, grasping equilibrium and force transmission. The feasibility of the herein proposed optimum design procedure for a finger-driving mechanism has been tested by numerical examples that have been also used to enhance a prototype previously built at LARM in Cassino.

  15. Design of control and safety rod and its drive mechanism of PFBR

    International Nuclear Information System (INIS)

    Rajan Babu, V.; Govindarajan, S.; Chetal, S.C.

    1997-01-01

    Control and Safety Rod (CSR) is one of the two types of absorber rods in shutdown systems of PFBR. Control and Safety Rod Drive Mechanism (CSRDM) actuates CSR to have vertical translatory motion in reactor core. The dual responsibilities entrusted on CSR to control reactor power during normal operating condition and to shutdown the reactor by scram action during abnormal condition, necessitate highly reliable design, analysis, testing and surveillance of CSR and CSRDM. The paper discusses on the salient features of CSR and CSRDM and design and analysis of individual sub-assemblies, viz., gripper, scram-release electromagnet, hydraulic dash pot, seals. Also it discusses on the developmental activities proposed and surveillance test requirements. (author)

  16. MECHANICAL PROPERTIES OF THIN GDP SHELLS USED AS CRYOGENIC DIRECT DRIVE TARGETS AT OMEGA

    International Nuclear Information System (INIS)

    NIKROO, A.; CZECHOWICZ, D.; CHEN, K.C.; DICKEN, M.; MORRIS, C.; ANDREWS, R.; GREENWOOD, A.L; CASTILLO, E.

    2003-09-01

    OAK-B135 Thin glow discharge polymer (GDP) shells are currently used as the targets for cryogenic direct drive laser fusion experiments. These shells need to be filled with nearly 1000 atm of D 2 and cooled to cryogenic temperatures without failing due to buckling and bursting pressures they experience in this process. Therefore, the mechanical and permeation properties of these shells are of utmost importance in successful and rapid filling with D 2 . In this paper, they present an overview of buckle and burst pressures of several different types of GDP shells. These include those made using traditional GDP deposition parameters (standard GDP) using a high deposition pressure and using modified parameters (strong GDP) of low deposition pressure that leads to more robust shells

  17. A Review of Tribological Coatings for Control Drive Mechanisms in Space Reactors

    International Nuclear Information System (INIS)

    CJ Larkin; JD Edington; BJ Close

    2006-01-01

    Tribological coatings must provide lubrication for moving components of the control drive mechanism for a space reactor and prevent seizing due to friction or diffusion welding to provide highly reliable and precise control of reflector position over the mission lifetime. Several coatings were evaluated based on tribological performance at elevated temperatures and in ultrahigh vacuum environments. Candidates with proven performance in the anticipated environment are limited primarily to disulfide materials. Irradiation data for these coatings is nonexistent. Compatibility issues between coating materials and structural components may require the use of barrier layers between the solid lubricant and structural components to prevent deleterious interactions. It would be advisable to consider possible lubricant interactions prior to down-selection of structural materials. A battery of tests was proposed to provide the necessary data for eventual solid lubricant/coating selection

  18. Polymide composite evaluated as a candidate for a traction drive mechanism for space use

    Science.gov (United States)

    Sato, Tomoyuki; Nishimura, Makoto; Mizumoto, Muneo; Koseki, Humio; Ezawa, Naoya; Umemoto, Noboru

    To investigate the possibility of applying polymers in a traction drive mechanism for use in space, 16 polyimide composites were evaluated in vacuum and the results compared with similar results for two types of steel. A rolling-sliding friction apparatus with two cylindrical rollers was used in these experiments. Three combinations of materials were tested: polyimide/stainless steel (SUS440C), stainless steel (SUS440C)/stainless steel (SUS440C), and nitriding steel (SACM645)/nitriding steel (SACM645). While there was variation in the wearing rates of the polyimides, the maximum traction coefficients were all 0.15 or less. These results show that the polyimide/steel combination can be used for transmitting rotation, but not for transmitting power.

  19. The test for electromagnet of control element drive mechanism for SMART

    International Nuclear Information System (INIS)

    Cho, D. H.; Jeong, K. S.; Kim, J. H.; Hur, H.; Kim, J. I.

    2001-01-01

    The electromagnet installed in the ball-screw type control element drive mechanism for SMART is the necessary parts for quick insertion of the control element into the core on scram state. The electromagnet is the state holding on to the moving parts by electromagnet force during normal operation, but on the scram situation, the moving parts are quickly inserted by gravity force by turning off the power supplied to the electromagnet. In this paper, by the pre-making part test of the electromagnet the electromagnet thrust forces by the air gap between anchors, the size of current density supplied and the circumferential fluid temperature are obtained. The results by this test are compared with those by the finite element analysis. The test results can be used as a reference data for electromagnet design

  20. Study on electromagnetism force of CARR control rod drive mechanism experimental machine

    International Nuclear Information System (INIS)

    Zhu Xuewei; Zhen Jianxiao; Wang Yulin; Jia Yueguang; Yang Kun; Yin Haozhe

    2015-01-01

    With the aim of acquiring electromagnetic force and electromagnetic field distributions of control rod drive mechanism (CRDM) in China Advanced Research Reactor (CARR), the force analysis on the CRDM was taken. Manufacturing the experimental machine, the electromagnetic force experiment was taken on it. The electromagnetic field and electromagnetic force simulation analyses of experimental machine were taken, working out distribution data of electromagnetic force and magnetic induction intensity distribution curve, and the effects of permanent magnetic field on electromagnetic field and structure parameters on electromagnetic force. The simulation value is accord with experiment value, the research results provide a reference to electromagnetic force study on CRDM in CARR, and also provide a reference to design of the same type CRDM. (authors)

  1. Electromagnetic and thermal analysis of electromagnet for SMART control element drive mechanism

    International Nuclear Information System (INIS)

    Huh, H.; Kim, J. H.; Park, J. S.; Kim, Y. W.; Kim, J. I.

    1999-01-01

    A numerical electromagnetic and thermal analysis was performed for the electromagnet which is installed in the control element drive mechanism(CEDM) of the integral reactor SMART. A model for the electromagnetic analysis of the electromagnet was developed and theoretical bases for the model were established. Design parameters related to thrust force were identified, and the optimum design point was determined by analyzing the trend of the magnetic saturation with finite element method. Also It is important that the temperature of the electomagnet windings be maintained within the allowable limit of the insulation, since the electromagnet of CEDM is always supplied with current during the reactor operation. So the thermal analysis of the winding insulation which is composed of polyimide and air were performed by finite element method. The electromagnetic and thermal properties obtained here will be used as input for the optimization analysis of the electromagnet

  2. A Review of Tribological Coatings for Control Drive Mechanisms in Space Reactors

    Energy Technology Data Exchange (ETDEWEB)

    CJ Larkin; JD Edington; BJ Close

    2006-02-21

    Tribological coatings must provide lubrication for moving components of the control drive mechanism for a space reactor and prevent seizing due to friction or diffusion welding to provide highly reliable and precise control of reflector position over the mission lifetime. Several coatings were evaluated based on tribological performance at elevated temperatures and in ultrahigh vacuum environments. Candidates with proven performance in the anticipated environment are limited primarily to disulfide materials. Irradiation data for these coatings is nonexistent. Compatibility issues between coating materials and structural components may require the use of barrier layers between the solid lubricant and structural components to prevent deleterious interactions. It would be advisable to consider possible lubricant interactions prior to down-selection of structural materials. A battery of tests was proposed to provide the necessary data for eventual solid lubricant/coating selection.

  3. Optical Method for Detecting Displacements and Strains at Ultra-High Temperatures During Thermo-Mechanical Testing

    Science.gov (United States)

    Smith, Russell W. (Inventor); Rivers, H. Kevin (Inventor); Sikora, Joseph G. (Inventor); Roth, Mark C. (Inventor); Johnston, William M. (Inventor)

    2016-01-01

    An ultra-high temperature optical method incorporates speckle optics for sensing displacement and strain measurements well above conventional measurement techniques. High temperature pattern materials are used which can endure experimental high temperature environments while simultaneously having a minimum optical aberration. A purge medium is used to reduce or eliminate optical distortions and to reduce, and/or eliminate oxidation of the target specimen.

  4. Development of linear pulse motor type control element drive mechanism for smart

    International Nuclear Information System (INIS)

    Je-Yong, Yu; Jong-in, Kim; Ji-ho, Kim; Hyung, Huh; Moon-Hee, Chang

    2001-01-01

    The system-integrated modular advanced reactor (SMART) currently under development at the Korea Atomic Energy Research Institute is being designed with soluble boron free operation and the use of nuclear heating for reactor start-up. These design features require a Control Element Drive Mechanism(CEDM) for SMART to have fine-step movement capability as well as high reliability for fine reactivity control. In this paper, the design characteristics of a new concept CEDM driven by a Linear Pulse Motor (LPM) which meets the design requirements of the integral reactor SMART are introduced. The primary dimensions of the linear pulse motor are determined by electro-magnetic analysis and the results are also presented. In parallel with the electro-magnetic analysis, the conceptual design of the CEDM is visualized and checked for interferences among parts by assembling three dimensional (3D) models on computer. A prototype of the LPM with double air-gaps for the CEDM sub-assemblies to lift 100 kg is designed, analysed, manufactured and tested to confirm the validity of the CEDM design concept. A converter and test facility are manufactured to verify the dynamic performance of the LPM. The mover of the LPM is welded with ferromagnetic material and non-ferromagnetic material to get the magnetic flux path between the inner stator and outer stator. The thrust forces of LPM predicted by the analytic model have shown good agreement with experimental results from the prototype LPM. It is found that the LPM type CEDM has high force density and a simple drive mechanism to reduce volume and satisfy reactor operating circumstances with high pressure and temperature. (authors)

  5. Linear pulse motor type control element drive mechanism for the integral reactor

    International Nuclear Information System (INIS)

    Yu, J. Y.; Choi, S.; Kim, J. H.; Huh, H.; Park, K. B.

    2007-01-01

    The integral reactor SMART currently under development at Korea Atomic Energy Research Institute is designed with soluble boron free operation and use of nuclear heating for reactor startup. These design features require the Control Element Drive Mechanism (CEDM) for SMART to have fine-step movement capability as well as high reliability for the fine reactivity control. In this paper, design characteristics of a new concept CEDM driven by the Linear Pulse Motor (LPM) which meets the design requirements of the integral reactor SMART are introduced. The primary dimensions of the linear pulse motor are determined by the electro-magnetic analysis and the results are also presented. In parallel with the electro-magnetic analysis, the conceptual design of the CEDM is visualized and checked for interferences among parts by assembling three dimensional (3D) models on the computer. Prototype of LPM with double air-gaps for the CEDM sub-assemblies to lift 100 kg is designed, analysed, manufactured and tested to confirm the validity of the CEDM design concept. A converter and a test facility are manufactured to verify the dynamic performance of the LPM. The mover of the LPM is welded with ferromagnetic material and non-ferromagnetic material to get the magnetic flux path between inner stator and outer stator. The thrust forces of LPM predicted by analytic model have shown good agreement with experimental results from the prototype LPM. It is found that the LPM type CEDM has high force density and simple drive mechanism to reduce volume and satisfy the reactor operating circumstances with high pressure and temperature

  6. Development and design of control rod drive mechanisms for pressurized water reactors

    International Nuclear Information System (INIS)

    Leme, Francisco Louzano

    2003-01-01

    The Control Rod Drive Mechanisms (CRDM) for a Pressurized Water Reactor (PWR) are equipment, integrated to the reactor pressure vessel, incorporating mechanical and electrical components designed to move and position the control rods to guarantee the control of power and shutdown of the nuclear reactor, during normal operation, either in emergency or accidental situations. The type of CRDM used in PWR reactors, whose detailed individual description will be presented in this monograph are the Roller-Nut and Magnetic-Jack. The environment, where the CRDM performs its above presented operational functions, includes direct contact with the fluid used as coolant peculiar to the interior of the reactor, and its associated chemical characteristics, the radiation field next to the reactor core, and also the temperature and pressure in the reactor pressure vessel. So the importance of the CRDM design requirements related to its safety functions are emphasized. Finally, some aspects related to the mechanical and structural design of CRDM of a case study, considering the CRDM for a PWR from the experimental nuclear plant to be applied by CTMSP (Centro Tecnologico da Marinha em Sao Paulo), are pointed out. The design and development of these equipment (author)

  7. Determination on Damage Mechanism of the Planet Gear of Heavy Vehicle Final Drive

    Science.gov (United States)

    Ramdan, RD; Setiawan, R.; Sasmita, F.; Suratman, R.; Taufiqulloh

    2018-02-01

    The works focus on the investigation of damage mechanism of fractured in the form of spalling of the planet gears from the final drive assembly of 160-ton heavy vehicles. The objective of this work is to clearly understand the mechanism of damage. The work is the first stage of the on-going research on the remaining life estimation of such gears. The understanding of the damage mechanism is critical in order to provide accurate estimate of the gear’s remaining life with observed initial damage. The analysis was performed based on the metallurgy laboratory works, including visual observation, macro-micro fractography by optical stereo and optical microscope and micro-vickers hardness test. From visual observation it was observed pitting that form lining defect at common position, which is at gear flank position. From spalling sample it was observed ratchet mark at the boundary between macro pitting and the edge of fractured parts. Further observation on the cross-section of the samples by optical microscope confirm that initial micro pitting occur without spalling of the case hardened surface. Spalling occur when pitting achieve certain critical size, and occur at multiple initiation site of crack propagation. From the present research it was concluded that pitting was resulted due to repeated contact fatigue. In addition, development of micro to macro pitting as well as spalling occur at certain direction towards the top of the gear teeth.

  8. Damped Least-Square Method Based on Chaos Anti-Control for Solving Forward Displacement of General 6-6-Type Parallel Mechanism

    Directory of Open Access Journals (Sweden)

    Youxin Luo

    2013-04-01

    Full Text Available Machine tools based on a Stewart platform are considered the machine tools of the 21st century. Difficult problems exist in the design philosophy, of which forward displacement analysis is the most fundamental. Its mathematical model is a kind of strongly nonlinear multivariable equation set with unique characteristics and a high level of difficulty. Different variable numbers and different solving speeds can be obtained through using different methods to establish the model of forward displacement analysis. The damped least-square method based on chaos anti-control for solving displacement analysis of the general 6-6-type parallel mechanism was built up through the rotation transformation matrix R, translation vector P and the constraint conditions of the rod length. The Euler equations describing the rotational dynamics of a rigid body with principle axes at the centre of mass were converted to a chaotic system by using chaos anti-control, and chaotic sequences were produced using the chaos system. Combining the characteristics of the chaotic sequence with the damped least-square method, all real solutions of forward displacement in nonlinear equations were found. A numerical example shows that the new method has some interesting features, such as fast convergence and the capability of acquiring all real solutions, and comparisons with other methods prove its effectiveness and validity.

  9. Displacing use

    DEFF Research Database (Denmark)

    Kelly, Janet; Matthews, Ben

    2014-01-01

    This paper critically discusses the concept of use in design, suggesting that relevant relationships other than use are sometimes obscured by the usercentredness of design processes. We present a design case from the medical device domain that displaced the concept of use from the centre of a human...

  10. Displacement Ventilation

    DEFF Research Database (Denmark)

    Bjørn, Erik; Mattsson, Magnus; Sandberg, Mats

    Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment...

  11. Development of in-vessel type control rod drive mechanism for a innovative small reactor (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Yoritsune, Tsutomu; Ishida, Toshihisa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Although the control rod drive mechanism of an existing large scale light water reactor is generally installed outside the reactor vessel, an in-vessel type control rod drive mechanism (INV-CRDM) is installed inside the reactor vessel. The INV-CRDM contributes to compactness and simplicity of the reactor system, and it can eliminate the possibility of a rod ejection accident. Therefore, INV-CRDM is an important technology adopted in an innovative small reactor. Japan Atomic Energy Research Institute (JAERI) has developed this type of CRDM driven by an electric motor, which can work under high temperature and high pressure water for the advanced marine reactor. On the basis of this research result, a driving motor coil and a bearing were developed to be used under the high temperature steam, severe condition for an innovative small reactor. About the driving motor, we manufactured the driving motor available for high temperature steam and carried out performance test under room temperature atmosphere to confirm the electric characteristic and coolability of the driving coil. With these test results and the past test results under high temperature water, we analyzed and evaluated the electric performance and coolability of the driving coil under high temperature steam. Concerning bearing, we manufactured the test pieces using some candidate material for material characteristic test and carried out the rolling wear test under high temperature steam to select the material. Consequently, we confirmed that performance of the driving coil for the advanced type driving motor, is enough to be used under high temperature steam. And, we evaluated the performance of the bearing and selected the material of the bearing, which can be used under high temperature steam. From these results, we have obtained the prospect that the INV-CRDM can be used for an innovative small reactor under steam atmosphere could be developed. (author)

  12. Testing and qualification of Control and Safety Rod and its drive mechanism of Fast Breeder Reactor

    International Nuclear Information System (INIS)

    Rajan Babu, V.; Veerasamy, R.; Patri, Sudheer; Ignatius Sundar Raj, S.; Kumar Krovvidi, S.C.S.P.; Dash, S.K.; Meikandamurthy, C.; Rajan, K.K.; Puthiyavinayagam, P.; Chellapandi, P.; Vaidyanathan, G.; Chetal, S.C.

    2010-01-01

    Prototype Fast Breeder Reactor (PFBR) has two independent fast acting diverse shutdown systems. The absorber rod of the first system is called Control and Safety Rod (CSR). CSR and its Drive Mechanism (CSRDM) are used for reactor control and for safe shutdown of the reactor by scram action. In view of the safety role, the qualification of CSRDM is one of the important requirements. CSR and CSRDM were qualified in two stages by extensive testing. In the first stage, the critical subassemblies of the mechanism, such as scram release electromagnet, hydraulic dashpot and dynamic seals and CSR subassembly, were tested and qualified individually simulating the operating conditions of the reactor. Experiments were also carried out on sodium vapour deposition in the annular gaps between the stationary and mobile parts of the mechanism. In the second stage, full-scale CSRDM and CSR were subjected to all the integrated functional tests in air, hot argon and subsequently in sodium simulating the operating conditions of the reactor and finally subjected to endurance tests. Since the damage occurring in CSRDM and CSR is mainly due to fatigue cycles during scram actions, the number of test cycles was decided based on the guidelines given in ASME, Section III, Div. 1. The results show that the performance of CSRDM and CSR is satisfactory. Subsequent to the testing in sodium, the assemblies having contact with liquid sodium/sodium vapour were cleaned using CO 2 process and the total cleaning process has been established, so that the mechanism can be reused in sodium. The various stages of qualification programmes have raised the confidence level on the performance of the system as a whole for the intended and reliable operation in the reactor.

  13. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  14. Mechanisms driving local breast cancer recurrence in a model of breast-conserving surgery.

    LENUS (Irish Health Repository)

    Smith, Myles J

    2012-02-03

    OBJECTIVE: We aimed to identify mechanisms driving local recurrence in a model of breast-conserving surgery (BCS) for breast cancer. BACKGROUND: Breast cancer recurrence after BCS remains a clinically significant, but poorly understood problem. We have previously reported that recurrent colorectal tumours demonstrate altered growth dynamics, increased metastatic burden and resistance to apoptosis, mediated by upregulation of phosphoinositide-3-kinase\\/Akt (PI3K\\/Akt). We investigated whether similar characteristics were evident in a model of locally recurrent breast cancer. METHODS: Tumours were generated by orthotopic inoculation of 4T1 cells in two groups of female Balb\\/c mice and cytoreductive surgery performed when mean tumour size was above 150 mm(3). Local recurrence was observed and gene expression was examined using Affymetrix GeneChips in primary and recurrent tumours. Differential expression was confirmed with quantitative real-time polymerase chain reaction (qRT-PCR). Phosphorylation of Akt was assessed using Western immunoblotting. An ex vivo heat shock protein (HSP)-loaded dendritic cell vaccine was administered in the perioperative period. RESULTS: We observed a significant difference in the recurrent 4T1 tumour volume and growth rate (p < 0.05). Gene expression studies suggested roles for the PI3K\\/Akt system and local immunosuppression driving the altered growth kinetics. We demonstrated that perioperative vaccination with an ex vivo HSP-loaded dendritic cell vaccine abrogated recurrent tumour growth in vivo (p = 0.003 at day 15). CONCLUSION: Investigating therapies which target tumour survival pathways such as PI3K\\/Akt and boost immune surveillance in the perioperative period may be useful adjuncts to contemporary breast cancer treatment.

  15. Transcriptomic profile reveals gender-specific molecular mechanisms driving multiple sclerosis progression.

    Directory of Open Access Journals (Sweden)

    Haritz Irizar

    Full Text Available BACKGROUND: Although the most common clinical presentation of multiple sclerosis (MS is the so called Relapsing-Remitting MS (RRMS, the molecular mechanisms responsible for its progression are currently unknown. To tackle this problem, a whole-genome gene expression analysis has been performed on RRMS patients. RESULTS: The comparative analysis of the Affymetrix Human Gene 1.0 ST microarray data from peripheral blood leucocytes obtained from 25 patients in remission and relapse and 25 healthy subjects has revealed 174 genes altered in both remission and relapse, a high proportion of them showing what we have called "mirror pattern": they are upregulated in remission and downregulated in relapse or vice versa. The coexpression analysis of these genes has shown that they are organized in three female-specific and one male-specific modules. CONCLUSIONS: The interpretation of the modules of the coexpression network suggests that Epstein-Barr virus (EBV reactivation of B cells happens in MS relapses; however, qPCR expression data of the viral genes supports that hypothesis only in female patients, reinforcing the notion that different molecular processes drive disease progression in females and males. Besides, we propose that the "primed" state showed by neutrophils in women is an endogenous control mechanism triggered to keep EBV reactivation under control through vitamin B12 physiology. Finally, our results also point towards an important sex-specific role of non-coding RNA in MS.

  16. Fuzzy Diagnostic System for Oleo-Pneumatic Drive Mechanism of High-Voltage Circuit Breakers

    Directory of Open Access Journals (Sweden)

    Viorel Nicolau

    2013-01-01

    Full Text Available Many oil-based high-voltage circuit breakers are still in use in national power networks of developing countries, like those in Eastern Europe. Changing these breakers with new more reliable ones is not an easy task, due to their implementing costs. The acting device, called oleo-pneumatic mechanism (MOP, presents the highest fault rate from all components of circuit breaker. Therefore, online predictive diagnosis and early detection of the MOP fault tendencies are very important for their good functioning state. In this paper, fuzzy logic approach is used for the diagnosis of MOP-type drive mechanisms. Expert rules are generated to estimate the MOP functioning state, and a fuzzy system is proposed for predictive diagnosis. The fuzzy inputs give information about the number of starts and time of functioning per hour, in terms of short-term components, and their mean values. Several fuzzy systems were generated, using different sets of membership functions and rule bases, and their output performances are studied. Simulation results are presented based on an input data set, which contains hourly records of operating points for a time horizon of five years. The fuzzy systems work well, making an early detection of the MOP fault tendencies.

  17. Dynamic simulation of a beta-type Stirling engine with cam-drive mechanism via the combination of the thermodynamic and dynamic models

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chin-Hsiang; Yu, Ying-Ju [Department of Aeronautics and Astronautics, National Cheng Kung University, No. 1, Ta-Shieh Road, Tainan, Taiwan (China)

    2011-02-15

    Dynamic simulation of a beta-type Stirling engine with cam-drive mechanism used in concentrating solar power system has been performed. A dynamic model of the mechanism is developed and then incorporated with the thermodynamic model so as to predict the transient behavior of the engine in the hot-start period. In this study, the engine is started from an initial rotational speed. The torques exerted by the flywheel of the engine at any time instant can be calculated by the dynamic model as long as the gas pressures in the chambers, the mass inertia, the friction force, and the external load have been evaluated. The instantaneous rotation speed of the engine is then determined by integration of the equation of rotational motion with respect to time, which in return affects the instantaneous variations in pressure and other thermodynamic properties of the gas inside the chambers. Therefore, the transient variations in gas properties inside the engine chambers and the dynamic behavior of the engine mechanism should be handled simultaneously via the coupling of the thermodynamic and dynamic models. An extensive parametric study of the effects of different operating and geometrical parameters has been performed, and results regarding the effects of mass moment of inertia of the flywheel, initial rotational speed, initial charged pressure, heat source temperature, phase angle, gap size, displacer length, and piston stroke on the engine transient behavior are investigated. (author)

  18. Mechanisms driving the seasonality of catchment scale nitrate export: Evidence for riparian ecohydrologic controls

    Science.gov (United States)

    Duncan, Jonathan M.; Band, Lawrence E.; Groffman, Peter M.; Bernhardt, Emily S.

    2015-06-01

    Considerable variability in the seasonal patterns of stream water nitrate (NO3-) has been observed in forested watersheds throughout the world. While many forested headwater catchments exhibit winter and early spring peaks in NO3- concentrations, several watersheds have peak concentrations during the summer months. Pond Branch, a headwater catchment in Maryland monitored for over 10 years, exhibits recurrent and broad summer peaks in both NO3- concentrations and watershed export. Higher NO3- export from June to September is particularly surprising, given that these summer months typically have the year's lowest discharge. A key challenge is identifying the source(s) of NO3- and the mechanism(s) by which it is transported to the watershed outlet during the summer. In this study, we assessed multiple hypotheses (not mutually exclusive) that could account for the seasonal trend including proximal controls of groundwater-surface water interactions, instream processes, and riparian groundwater-N cycling interactions, as well as two distal controls: geochemical weathering and senescence of riparian vegetation. A combination of long-term weekly and limited duration high-frequency sensor data reveals the importance of riparian ecohydrologic processes during base flow. In this watershed, patterns of seasonal stream water NO3- concentrations and fluxes depend fundamentally on interactions between groundwater dynamics and nitrogen (N) cycling in the riparian zone. Groundwater tables control nitrification-denitrification dynamics as well as hydrologic transport. Our results suggest that in many watersheds, a more sophisticated exploration of NO3- production and NO3- transport mechanisms is required to identify critical points in the landscape and over time that disproportionately drive patterns of watershed NO3- export.

  19. Mechanisms driving carbon allocation in tropical rainforests: allometric constraints and environmental responses

    Science.gov (United States)

    Hofhansl, Florian; Schnecker, Jörg; Singer, Gabriel; Wanek, Wolfgang

    2014-05-01

    Tropical forest ecosystems play a major role in global water and carbon cycles. However, mechanisms of C allocation in tropical forests and their response to environmental variation are largely unresolved as, due to the scarcity of data, they are underrepresented in global syntheses of forest C allocation. Allocation of gross primary production to wood production exerts a key control on forest C residence time and biomass C turnover, and therefore is of special interest for terrestrial ecosystem research and earth system science. Here, we synthesize pantropical data from 105 old-growth rainforests to investigate relationships between climate (mean annual precipitation, mean annual temperature, dry season length and cloud cover), soil nutrient relations (soil N:P) and the partitioning of aboveground net primary production (ANPP) to wood production (WPart) using structural equation modelling. Our results show a strong increase of WPart with ANPP, pointing towards allometric scaling controls on WPart, with increasing light competition in more productive forests triggering greater ANPP allocation to wood production. ANPP itself was positively affected by mean annual temperature and soil N:P. Beyond these allometric controls on WPart we found direct environmental controls. WPart increased with dry season length in tropical montane rainforests and with mean annual precipitation in lowland tropical rainforests. We discuss different trade-offs between plant traits, such as community-wide changes along the wood economics spectrum, the leaf economics spectrum and the plant resource economics spectrum, as underlying mechanisms for direct climatic controls on WPart. We thereby provide new insights into mechanisms driving carbon allocation to WPart in tropical rainforests and show that low and high productive tropical rainforests may respond differently to projected global changes.

  20. Potential Mechanisms Driving Population Variation in Spatial Memory and the Hippocampus in Food-caching Chickadees.

    Science.gov (United States)

    Croston, Rebecca; Branch, Carrie L; Kozlovsky, Dovid Y; Roth, Timothy C; LaDage, Lara D; Freas, Cody A; Pravosudov, Vladimir V

    2015-09-01

    Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the

  1. On The Plausibility of The Gravitational Collapse As Driving Mechanism For Tectonic Extension

    Science.gov (United States)

    Viti, M.; Mantovani, E.; Albarello, D.

    The possibility that gravitational collapse of a thickened zone induces tensional failure in the lithosphere has quantitatively been investigated by comparing driving forces and lithospheric strength. The force induced by a lateral variation of crustal thickness has been estimated by the difference of gravitational potential energy stored in unit-area lithospheric columns, set in the thickened and reference domains. This force quadrati- cally depends on the thickness ratio and on the thickness of the reference lithosphere. The tensional strength of the thickened belt is obtained by its strength envelope, ten- tatively reconstructed by taking into account the gross petrological composition, the thermal state and the mechanical properties of the crust-mantle system. The effects of normal and hot geotherms (corresponding to a superficial heat flow density of 55 and 70 mW m-2, respectively) have also been investigated. Thickening of both oceanic and continental crust is considered. In the case of oceanic crust, the spreading force, obtained by increasing the crustal thickness up to 4 times the 5-km reference value, is considerably lower than the lithospheric strength, even when the tensional resis- tance is reduced by thermal weakening. Thus, the gravitational collapse of thickened oceanic zones appears to be unlikely. For continental domains, the effect of crustal thickening, up to 60 km, has been investigated. In this kind of structures, lithospheric strength rapidly decreases with the increase of crustal thickness. By assuming a nor- mal geotherm, the spreading force of a thickened (h>40 km) chain facing a 40 km thick foreland is always lower than the lithospheric strength. When a hot geotherm is assumed, the same orogenic belt may collapse when the thickness difference between the chain and the foreland exceeds 10 km. The collapse of an orogenic zone (h>20 km) surrounded by a 20 km-thick foreland occurs when the thickness difference is greater than 30 km, with a

  2. Combining displacement field and grip force information to determine mechanical properties of planar tissue with complicated geometry.

    Science.gov (United States)

    Nagel, Tina M; Hadi, Mohammad F; Claeson, Amy A; Nuckley, David J; Barocas, Victor H

    2014-11-01

    Performing planar biaxial testing and using nominal stress-strain curves for soft-tissue characterization is most suitable when (1) the test produces homogeneous strain fields, (2) fibers are aligned with the coordinate axes, and (3) strains are measured far from boundaries. Some tissue types [such as lamellae of the annulus fibrosus (AF)] may not allow for these conditions to be met due to their natural geometry and constitution. The objective of this work was to develop and test a method utilizing a surface displacement field, grip force-stretch data, and finite-element (FE) modeling to facilitate analysis of such complex samples. We evaluated the method by regressing a simple structural model to simulated and experimental data. Three different tissues with different characteristics were used: Superficial pectoralis major (SPM) (anisotropic, aligned with axes), facet capsular ligament (FCL) (anisotropic, aligned with axes, bone attached), and a lamella from the AF (anisotropic, aligned off-axis, bone attached). We found that the surface displacement field or the grip force-stretch data information alone is insufficient to determine a unique parameter set. Utilizing both data types provided tight confidence regions (CRs) of the regressed parameters and low parameter sensitivity to initial guess. This combined fitting approach provided robust characterization of tissues with varying fiber orientations and boundaries and is applicable to tissues that are poorly suited to standard biaxial testing. The structural model, a set of C++ finite-element routines, and a Matlab routine to do the fitting based on a set of force/displacement data is provided in the on-line supplementary material.

  3. The axolotl limb blastema: cellular and molecular mechanisms driving blastema formation and limb regeneration in tetrapods

    Science.gov (United States)

    McCusker, Catherine; Bryant, Susan V.

    2015-01-01

    Abstract The axolotl is one of the few tetrapods that are capable of regenerating complicated biological structures, such as complete limbs, throughout adulthood. Upon injury the axolotl generates a population of regeneration‐competent limb progenitor cells known as the blastema, which will grow, establish pattern, and differentiate into the missing limb structures. In this review we focus on the crucial early events that occur during wound healing, the neural−epithelial interactions that drive the formation of the early blastema, and how these mechanisms differ from those of other species that have restricted regenerative potential, such as humans. We also discuss how the presence of cells from the different axes of the limb is required for the continued growth and establishment of pattern in the blastema as described in the polar coordinate model, and how this positional information is reprogrammed in blastema cells during regeneration. Multiple cell types from the mature limb stump contribute to the blastema at different stages of regeneration, and we discuss the contribution of these types to the regenerate with reference to whether they are “pattern‐forming” or “pattern‐following” cells. Lastly, we explain how an engineering approach will help resolve unanswered questions in limb regeneration, with the goal of translating these concepts to developing better human regenerative therapies. PMID:27499868

  4. Electroacoustics: A New Mechanism for Driving Individually Addressable Jetting and Other Microfluidic Manipulations in Multiwell Arrays

    Science.gov (United States)

    Yeo, Leslie; Rezk, Amgad

    2017-11-01

    The low take-up of microfluidic technology at the laboratory bench despite 25 years of advances can be attributed to the reluctance of practitioners to adopt new and sophisticated technology, which requires substantial retraining, as well as the large investments that have already been made in the vast array of existing laboratory equipment. A way to circumvent this is to design microfluidic technology to retrofit existing laboratory technology such as microscope stages, microplate readers, etc. This is however not without challenge as existing microfluidic devices themselves often require large ancillary equipment to drive fluidic actuation/detection, which are not always amenable to integration into these existing laboratory formats. We have developed a low-cost and scalable modular plug-and-play microplatform that facilitates individual addressability of each well in a microarray plate for sample dispensing, mixing and preconcentration, as well as its ejection via jetting/nebulisation for subsequent analysis. As this cannot be achieved using standard acoustofluidics, we have developed a new electroacoustic mechanism that allows the transmission of high frequency sound waves into each well while uniquely confining the electric field off the piezoelectric chip.

  5. On a Small-scale EUV Wave: The Driving Mechanism and the Associated Oscillating Filament

    Science.gov (United States)

    Shen, Yuandeng; Liu, Yu; Tian, Zhanjun; Qu, Zhining

    2017-12-01

    We present observations of a small-scale extreme-ultraviolet (EUV) wave that was associated with a mini-filament eruption and a GOES B1.9 micro-flare in the quiet-Sun region. The initiation of the event was due to the photospheric magnetic emergence and cancellation in the eruption source region, which first caused the ejection of a small plasma ejecta, then the ejecta impacted a nearby mini-filament and thereby led to the filament’s eruption and the associated flare. During the filament eruption, an EUV wave at a speed of 182{--}317 {km} {{{s}}}-1 was formed ahead of an expanding coronal loop, which propagated faster than the expanding loop and showed obvious deceleration and reflection during the propagation. In addition, the EUV wave further resulted in the transverse oscillation of a remote filament whose period and damping time are 15 and 60 minutes, respectively. Based on the observational results, we propose that the small-scale EUV wave should be a fast-mode magnetosonic wave that was driven by the expanding coronal loop. Moreover, with the application of filament seismology, it is estimated that the radial magnetic field strength is about 7 Gauss. The observations also suggest that small-scale EUV waves associated with miniature solar eruptions share similar driving mechanisms and observational characteristics with their large-scale counterparts.

  6. Analytical Kinematics and Coupled Vibrations Analysis of Mechanical System Operated by Solar Array Drive Assembly

    Science.gov (United States)

    Sattar, M.; Wei, C.; Jalali, A.; Sattar, R.

    2017-07-01

    To address the impact of solar array (SA) anomalies and vibrations on performance of precision space-based operations, it is important to complete its accurate jitter analysis. This work provides mathematical modelling scheme to approximate kinematics and coupled micro disturbance dynamics of rigid load supported and operated by solar array drive assembly (SADA). SADA employed in analysis provides a step wave excitation torque to activate the system. Analytical investigations into kinematics is accomplished by using generalized linear and Euler angle coordinates, applying multi-body dynamics concepts and transformations principles. Theoretical model is extended, to develop equations of motion (EoM), through energy method (Lagrange equation). The main emphasis is to research coupled frequency response by determining energies dissipated and observing dynamic behaviour of internal vibratory systems of SADA. The disturbance model captures discrete active harmonics of SADA, natural modes and vibration amplifications caused by interactions between active harmonics and structural modes of mechanical assembly. The proposed methodology can help to predict true micro disturbance nature of SADA operating rigid load. Moreover, performance outputs may be compared against actual mission requirements to assess precise spacecraft controller design to meet next space generation stringent accuracy goals.

  7. Magnetic Actuation Connector Between Extension Shaft and Armature for Bottom Mounted Control Rod Drive Mechanism

    International Nuclear Information System (INIS)

    Huh, Hyung; Cho, Yeong Garp; Kim, Jong In

    2013-01-01

    The electromagnet and armature inside the guide tube interact and produce magnetism, thus making the armature, connecting extension shaft and control rod move up and down to control the power of reactor. During the overhaul, the control absorber rod (CAR), extension shaft, and armature of BMCRDM are lifted together for closing a seal valve. But total length of CAR assembly is so long that it cannot be lifted due to exposure above the water level of pool which is strictly controlled. In addition to this, it is difficult to calibrate a position indicator and lifting force of electromagnet without armature assembly as a seal valve is closed. For this reason, it is necessary to install a disconnecting system between armature and extension shaft. Therefore, KAERI has developed magnetic actuation connector using plunger between armature and extension shaft for the bottom mounted control rod drive mechanism in research reactor. The results of a FEM and the experiments in this work lead to the following conclusions: The FEM result for the design of the magnetic actuation connector is compared with the measured lifting force of prototype production. As a result, it is shown that the lifting force of the prototype connector has a good agreement with the result of the FEM. A newly developed technique of prototype magnetic actuation connector which is designed by FEM analysis result is proposed

  8. Driving mechanism of SOL plasma flow an effects on the divertor performance in JT-60U

    International Nuclear Information System (INIS)

    Asakura, Nobuyuki; Takenaga, H.; Sakurai, S.

    2003-01-01

    The measurements of the scrape-off layer(SOL) flow and plasma profiles both at the high-field-side (HFS) and low-field-side (LFS), for the first time, identified the SOL flow pattern and its driving mechanism. 'Flow reversal' was found near the HFS and LFS separatrix of the main plasma for the ion ∇B drift direction towards the divertor, Radial profiles of the SOL flow were similar to those calculated numerically using the UEDGE code with the plasma drifts included although Mach numbers in measurements were greater than those obtained numerically. Particle fluxes towards the HFS and LFS divertors produced by the parallel SOL flow and E r xB drift flow were evaluated. The particle flux for the case of intense gas puff and divertor pump (puff and pump) was investigated, and it was found that both the Mach number and collisionality were enhanced, in particular, at HFS. Drift flux in the private flux region was also evaluated, and important physics issues for the divertor design and operation, such as in-out asymmetries of the heat and particle fluxes, and control of impurity ions were investigated. (author)

  9. Driving mechanism of SOL plasma flow and effects on the divertor performance in JT-60U

    International Nuclear Information System (INIS)

    Asakura, N.; Takenaga, H.; Sakurai, S.

    2003-01-01

    The measurements of the SOL flow and plasma profiles both at the high-field-side (HFS) and low field- side (LFS), for the first time, identified the SOL flow pattern and its driving mechanism. 'Flow reversal' was found near the HFS and LFS separatrix of the main plasma for the ion ∇β drift direction towards the divertor. Radial profiles of the SOL flow were similar to those calculated numerically using the UEDGE code with the plasma drifts included although Mach numbers in measurements were greater than those obtained numerically. Particle fluxes towards the HFS and LFS divertors produced by the parallel SOL flow and E r xB drift flow were evaluated. The particle flux for the case of intense gas puff and divertor pump (puff and pump) was investigated, and it was found that both the Mach number and collisionality were enhanced, in particular, at HFS. Drift flux in the private flux region was also evaluated, and important physics issues for the divertor design and operation, such as in-out asymmetries of the heat and particle fluxes, and control of impurity ions were investigated. (author)

  10. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

    Science.gov (United States)

    Hagman, Arne; Piškur, Jure

    2015-01-01

    Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that were semi-anaerobic.

  11. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

    Directory of Open Access Journals (Sweden)

    Arne Hagman

    Full Text Available Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that

  12. Current understanding of the driving mechanisms for spatiotemporal variations of atmospheric speciated mercury: a review

    Directory of Open Access Journals (Sweden)

    H. Mao

    2016-10-01

    Full Text Available Atmospheric mercury (Hg is a global pollutant and thought to be the main source of mercury in oceanic and remote terrestrial systems, where it becomes methylated and bioavailable; hence, atmospheric mercury pollution has global consequences for both human and ecosystem health. Understanding of spatial and temporal variations of atmospheric speciated mercury can advance our knowledge of mercury cycling in various environments. This review summarized spatiotemporal variations of total gaseous mercury or gaseous elemental mercury (TGM/GEM, gaseous oxidized mercury (GOM, and particulate-bound mercury (PBM in various environments including oceans, continents, high elevation, the free troposphere, and low to high latitudes. In the marine boundary layer (MBL, the oxidation of GEM was generally thought to drive the diurnal and seasonal variations of TGM/GEM and GOM in most oceanic regions, leading to lower GEM and higher GOM from noon to afternoon and higher GEM during winter and higher GOM during spring–summer. At continental sites, the driving mechanisms of TGM/GEM diurnal patterns included surface and local emissions, boundary layer dynamics, GEM oxidation, and for high-elevation sites mountain–valley winds, while oxidation of GEM and entrainment of free tropospheric air appeared to control the diurnal patterns of GOM. No pronounced diurnal variation was found for Tekran measured PBM at MBL and continental sites. Seasonal variations in TGM/GEM at continental sites were attributed to increased winter combustion and summertime surface emissions, and monsoons in Asia, while those in GOM were controlled by GEM oxidation, free tropospheric transport, anthropogenic emissions, and wet deposition. Increased PBM at continental sites during winter was primarily due to local/regional coal and wood combustion emissions. Long-term TGM measurements from the MBL and continental sites indicated an overall declining trend. Limited measurements suggested TGM

  13. Development of a solar array drive mechanism for micro-satellite platforms

    Science.gov (United States)

    Galatis, Giorgos; Guo, Jian; Buursink, Jeroen

    2017-10-01

    Photovoltaic solar array (PVSA) systems are the most widely used method for spacecraft power generation. However, in many satellite missions, the optimum orientation of the PVSA system is not always compatible with that of the payload orientation. Many methods, have been examined in the past to overcome this problem. Up to date, the most widely used active method for large costly satellites is the Solar Array Drive Mechanism (SADM). The SADM serves as the interface between the satellite body and the PVSA subsystem, enabling the decoupling of their spatial orientation. Nonetheless, there exists a research and development gap for such systems regarding low cost micro-satellites. During the literature study of this paper, individual orbital parameters of various micro-satellites have been extracted and compared to the rotational freedom of the corresponding SADMs used. The findings demonstrated that the implemented SADMs are over designed. It is therefore concluded that these components are not tailored made for each spacecraft mission individually, but rather, exhibit a generic design to full fill a majority of mission profiles and requirements. Motivated by the above analysis, the cardinal objective of the current research is to develop a low cost mechanism that will be precisely tailored for the use of a low Earth orbit (LEO) micro-satellite platform orbiting in altitudes of 500 - 1000km . The design of the mechanism may vary from the existing miniaturized SADMs. For example, the preliminary analysis of the current research suggests, that the conventional use of the slip ring system as the electronic transfer unit can be replaced by a seMI Orientation Unit (MIOU). Systems engineering tools for concept generation and selection have been used. In addition, simulation and mathematical modelling have been implemented on component and system level, to accurately predict the behaviour of the system under various modes of operation. The production and system testing of

  14. Maintenance of working capacity of movement mechanism of load trolley with linear traction electric drive of bridge type crane.

    Science.gov (United States)

    Goncharov, K. A.; Denisov, I. A.

    2017-10-01

    The article considers the influence of the air gap size between the linear motor elements on the stability of the traction drive of the movement mechanism of the trolley of the bridge type crane. The main factors affecting the air gap size and the causes of their occurrence are described. The technique of calculating the magnitude of air gap variation is described in relation to the general deformation of the crane metal structure. Recommendations on the need for installation of additional equipment for load trolleys of various designs are given. The optimal values of the length of the trolley base are proposed. Observance of these values ensures normal operation of the traction drive.

  15. Reversible Gene Drive Mechanism Utilizing Trana Inactivating Paramutatlons In Insects (paramutale 0.9)

    Energy Technology Data Exchange (ETDEWEB)

    2017-09-06

    The paramutate software package Is a tool to calculate the genotyplc and phenotyplc propagation of a gene drive that can be silenced with a homologuus trans-Inactivating panmutatlon, ln dlptera or other species with a slmUar-acttng pl RNA system/Plwi pathway. Method of SolaUon: paramutate uses rults of Mendelian, gene drive (I.e.. stimulated conversion), and maternal Inheritance to compute the propaptlon of a notional gene drive construct and Its trans-lnactlvat1n1 paramutatlon, throu1b a panmlctlc, fixed-size population reproducing In synchronous generations.

  16. Driving mechanism of low salinity flooding in carbonate rocks (SPE-174300-MS)

    NARCIS (Netherlands)

    Mahani, Hassan; Berg, Steffen; Keya, Arsene; Bartels, W.; Nasralla, Ramez; Rossen, William

    2015-01-01

    Several studies conducted mainly on the laboratory scale indicate that in carbonate rocks oil displacement can be influenced by the ionic composition of the brine, providing an opportunity to improve recovery by optimizing the brine mixture used in secondary or tertiary recovery. In industry this

  17. Digital displacements

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co...... digital reforms in Denmark and shows how citizen service is transformed from service to support. The frontline employee’s classical tasks such as casework are being displaced into educational and support-oriented tasks with less professional content. Thus an unintended effect of digitisation is blurred......In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...

  18. NDE of Possible Service-Induced PWSCC in Control Rod Drive Mechanism Housings Removed from Service

    International Nuclear Information System (INIS)

    Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.; Harris, Robert V.; Crawford, Susan L.

    2006-01-01

    Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are being performed to assess the effectiveness of nondestructive examination (NDE) techniques on removed-from-service control rod drive mechanism (CRDM) nozzles and the associated J-groove attachment welds. This work is being performed to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE techniques such as ultrasonic testing (UT), eddy current testing (ET), and visual testing (VT) as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. The basic NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on the J-groove weld and buttering. This paper describes the NDE measurements that were employed on the two CRDMs to detect and characterize the indications and the analysis of these indications. The two CRDM assemblies were removed from service from the North Anna 2 vessel head, including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material. One nozzle contains suspected PWSCC, based on in-service inspection data; the second contains evidence suggesting through-wall leakage, although this was unconfirmed. A destructive test plan is being developed to directly characterize the indications found using nondestructive testing. The results of this destructive testing will be included when the destructive testing is completed.

  19. Displacement measurement system for linear array detector

    International Nuclear Information System (INIS)

    Zhang Pengchong; Chen Ziyu; Shen Ji

    2011-01-01

    It presents a set of linear displacement measurement system based on encoder. The system includes displacement encoders, optical lens and read out circuit. Displacement read out unit includes linear CCD and its drive circuit, two amplifier circuits, second order Butterworth low-pass filter and the binarization circuit. The coding way is introduced, and various parts of the experimental signal waveforms are given, and finally a linear experimental test results are given. The experimental results are satisfactory. (authors)

  20. Design optimization of dual-axis driving mechanism for satellite antenna with two planar revolute clearance joints

    Science.gov (United States)

    Bai, Zheng Feng; Zhao, Ji Jun; Chen, Jun; Zhao, Yang

    2018-03-01

    In the dynamic analysis of satellite antenna dual-axis driving mechanism, it is usually assumed that the joints are ideal or perfect without clearances. However, in reality, clearances in joints are unavoidable due to assemblage, manufacturing errors and wear. When clearance is introduced to the mechanism, it will lead to poor dynamic performances and undesirable vibrations due to impact forces in clearance joint. In this paper, a design optimization method is presented to reduce the undesirable vibrations of satellite antenna considering clearance joints in dual-axis driving mechanism. The contact force model in clearance joint is established using a nonlinear spring-damper model and the friction effect is considered using a modified Coulomb friction model. Firstly, the effects of clearances on dynamic responses of satellite antenna are investigated. Then the optimization method for dynamic design of the dual-axis driving mechanism with clearance is presented. The objective of the optimization is to minimize the maximum absolute vibration peak of antenna acceleration by reducing the impact forces in clearance joint. The main consideration here is to optimize the contact parameters of the joint elements. The contact stiffness coefficient, damping coefficient and the dynamic friction coefficient for clearance joint elements are taken as the optimization variables. A Generalized Reduced Gradient (GRG) algorithm is used to solve this highly nonlinear optimization problem for dual-axis driving mechanism with clearance joints. The results show that the acceleration peaks of satellite antenna and contact forces in clearance joints are reduced obviously after design optimization, which contributes to a better performance of the satellite antenna. Also, the application and limitation of the proposed optimization method are discussed.

  1. Study on fundamental mechanism of nuclear advanced robot. Some consideration of driving mechanism on remotely operated and submerged vehicle using the maintenance for nuclear power plant

    International Nuclear Information System (INIS)

    Ohki, Arahiko; Hirano, Sigeo; Oogihara, Hirotugu

    1998-01-01

    A propulsion system of fish was studied as a research of the driving mechanism of robot for nuclear maintenance in water. Fish sailing with higher speed than a constant value can sail by an Ostraciform type swimming method. Fish can advance by a winding actuation. The movement of fishes trunk and caudal at the stationary movement was studied in this paper. The hypothetical formulae of movement were constructed on the basis of the movements of trunk and caudal. The elements related to the driving force were analysed and evaluated. Then, a model for reproducing the movement was designed. The movement of model was tested. The theoretical formula proved that the driving forces were consisted of the force vectors in the forward direction to be generated by the phase differences of each points of trunk and caudal in their cyclic movements. (S.Y.)

  2. Two-step mechanism for modifier of transcription 1 (Mot1) enzyme-catalyzed displacement of TATA-binding protein (TBP) from DNA.

    Science.gov (United States)

    Moyle-Heyrman, Georgette; Viswanathan, Ramya; Widom, Jonathan; Auble, David T

    2012-03-16

    The TATA box binding protein (TBP) is a central component of the transcription preinitiation complex, and its occupancy at a promoter is correlated with transcription levels. The TBP-promoter DNA complex contains sharply bent DNA and its interaction lifetime is limited by the ATP-dependent TBP displacement activity of the Snf2/Swi2 ATPase Mot1. Several mechanisms for Mot1 action have been proposed, but how it catalyzes TBP removal from DNA is unknown. To better understand the Mot1 mechanism, native gel electrophoresis and FRET were used to determine how Mot1 affects the trajectory of DNA in the TBP-DNA complex. Strikingly, in the absence of ATP, Mot1 acts to unbend DNA, whereas TBP remains closely associated with the DNA in a stable Mot1-TBP-DNA ternary complex. Interestingly, and in contrast to full-length Mot1, the isolated Mot1 ATPase domain binds DNA, and its affinity for DNA is nucleotide-dependent, suggesting parallels between the Mot1 mechanism and DNA translocation-based mechanisms of chromatin remodeling enzymes. Based on these findings, a model is presented for Mot1 that links a DNA conformational change with ATP-induced DNA translocation.

  3. Emotional dysregulation and anxiety control in the psychopathological mechanism underlying drive for thinness

    Directory of Open Access Journals (Sweden)

    Francesca eFiore

    2014-04-01

    Full Text Available Emotional dysregulation is a process which consists in mitigating, intensifying or maintaining a given emotion and is the trigger for some psychological disorders. Research has shown that a anxiety control plays an important role in emotional expression and regulation and, in addition, for anorexia nervosa and, more in general, in drive for thinness. Scientific literature suggests that in anorexia nervosa there is a core of emotional dysregulation and anxiety control. The aim of this study is to explore the roles of emotional dysregulation and anxiety control as independent or third variables in a mediational regression model related to drive for thinness. 154 clinical individuals with anorexia participated in the study and all completed a set of self-report questionnaires: eating disorders inventory version 3 (EDI-3, DERS, and the anxiety control questionnaire (ACQ. The data confirmed a mediational model in which the relation between emotional dysregulation and drive for thinness is mediated by anxiety control. The current study partially supports a clinical model in which emotional dysregulation is a distal factor in eating disorders while the mediator variable anxiety control is a proximal factor in the psychopathological process underlying it.

  4. An analysis of the mechanism of a reactivated basaltic landslide site under varying rate of displacement in Mauritius, Offshore Africa

    Science.gov (United States)

    Dabycharun, Bhoopendra; Kuwano, Takeshi; Ichikawa, Kensuke; Fukuoka, Hiroshi

    2017-04-01

    During the past 20 years, the continuous weathering of the soil on sloping areas has greatly contributed to landslide-prone geo-environment in Mauritius. Consequently, the landslide areas became a matter of interest for the government of Mauritius. This research has been focused on an existing landslide area namely Chitrakoot in Mauritius which is 1.8 km2 and was monitored by JICA (Japan International Cooperation Agency) and Ministry of Public Infrastructure and Land Transport of Government of Mauritius from 2012 to 2015. In 2005, 54 houses and infrastructures were affected with the activation of the landslide and which further reactivated in 2006 damaging another 14 houses. During the investigation conducted by JICA's Experts, a landslide block of 300 m by 150 m in a highly populated zone was found to be unstable. To monitor the behaviour of the landslide, two extensometers were installed together with piezometers. The extensometers revealed that the unstable block kept moving after the event with accelerating movement during and after a heavy rainfall and cyclonic conditions. Moreover, the piezometers concluded that the groundwater rises above the ground surface in the rainy season. To examine the mechanism of the reactivated landslide, disturbed samples were taken from the shear zone and were tested in the laboratories of Niigata University, Japan. The borehole core logging data obtained from 6 boreholes showed that possible sliding surface was observed in the colluvium layer consisting of gravels and stiff silty-clays, at depths from 6 to 10 m below the ground surface. Atterberg limits test for the soil showed that the soil had a liquid limit of 67.0%, plastic limit of 27.4 % and plasticity index of 39.26. The soil being of low plasticity possesses few inter-particle contact points and hence low shear stresses. Ring shear test was conducted under dry condition, fully saturated drained and undrained condition to examine the shear behaviour of the soil. Under the

  5. Mathematical modelling of performance of safety rod and its drive mechanism in sodium cooled fast reactor during scram action

    International Nuclear Information System (INIS)

    Rajan Babu, V.; Thanigaiyarasu, G.; Chellapandi, P.

    2014-01-01

    Highlights: • Mathematical modelling of dynamic behaviour of safety rod during scram action in fast reactor. • Effects of hydraulics, structural interaction and geometry on drop time of safety rod are understood. • Using simplified model, drop time can be assessed replacing detailed CFD analysis. • Sensitivities of the related parameters on drop time are understood. • Experimental validation qualifies the modelling and computer software developed. - Abstract: Performance of safety rod and its drive mechanism which are parts of shutdown systems in sodium cooled fast reactor (SFR) plays a major role in ensuring safe operation of the plant during all the design basis events. The safety rods are to be inserted into the core within a stipulated time during off-normal conditions of the reactor. Mathematical modelling of dynamic behaviour of a safety rod and its drive mechanism in a typical 500 MWe SFR during scram action is considered in the present study. A full-scale prototype system has undergone qualification tests in air, water and in sodium simulating the operating conditions in the reactor. In this paper, the salient features of the safety rod and its mechanism, details related to mathematical modelling and sensitivity of the parameters having influence on drop time are presented. The outcomes of the numerical analysis are compared with the experimental results. In this process, the mathematical model and the computer software developed are validated

  6. PLZT Ceramic Driving Rotary Micro-mirror Based on Photoelectric-electrostatic Mechanism

    Science.gov (United States)

    Tang, Yujuan; Yang, Zhong; Chen, Yusong; Wang, Xinjie

    2017-12-01

    Based on the anomalous photovoltaic effect of PLZT, a rotary micro-mirror driven by hybrid photoelectric-electrostatic actuation of PLZT ceramic is proposed. Firstly, the mathematical modelling of coupled multi-physics fields of PLZT ceramic is established during illumination and light off phases. Then, the relationship between the rotation angle and the photovoltage of PLZT ceramics is established. In addition, the feasibility of rotary micro-mirror with hybrid photoelectric-electrostatic driving is verified via closed-loop control for photo-induced voltage of PLZT ceramic. The experimental results show that the photo-induced voltage of PLZT ceramics has good dynamic control precision using on-off closed-loop control method.

  7. The driving mechanisms of particle precipitation during the moderate geomagnetic storm of 7 January 2005

    Directory of Open Access Journals (Sweden)

    N. Longden

    2007-10-01

    Full Text Available The arrival of an interplanetary coronal mass ejection (ICME triggered a sudden storm commencement (SSC at ~09:22 UT on the 7 January 2005. The ICME followed a quiet period in the solar wind and interplanetary magnetic field (IMF. We present global scale observations of energetic electron precipitation during the moderate geomagnetic storm driven by the ICME. Energetic electron precipitation is inferred from increases in cosmic noise absorption (CNA recorded by stations in the Global Riometer Array (GLORIA. No evidence of CNA was observed during the first four hours of passage of the ICME or following the sudden commencement (SC of the storm. This is consistent with the findings of Osepian and Kirkwood (2004 that SCs will only trigger precipitation during periods of geomagnetic activity or when the magnetic perturbation in the magnetosphere is substantial. CNA was only observed following enhanced coupling between the IMF and the magnetosphere, resulting from southward oriented IMF. Precipitation was observed due to substorm activity, as a result of the initial injection and particles drifting from the injection region. During the recovery phase of the storm, when substorm activity diminished, precipitation due to density driven increases in the solar wind dynamic pressure (Pdyn were identified. A number of increases in Pdyn were shown to drive sudden impulses (SIs in the geomagnetic field. While many of these SIs appear coincident with CNA, SIs without CNA were also observed. During this period, the threshold of geomagnetic activity required for SC driven precipitation was exceeded. This implies that solar wind density driven SIs occurring during storm recovery can drive a different response in particle precipitation to typical SCs.

  8. Robust design of microelectronics assemblies against mechanical shock, temperature and moisture effects of temperature, moisture and mechanical driving forces

    CERN Document Server

    Wong, E-H

    2015-01-01

    Robust Design of Microelectronics Assemblies Against Mechanical Shock, Temperature and Moisture discusses how the reliability of packaging components is a prime concern to electronics manufacturers. The text presents a thorough review of this important field of research, providing users with a practical guide that discusses theoretical aspects, experimental results, and modeling techniques. The authors use their extensive experience to produce detailed chapters covering temperature, moisture, and mechanical shock induced failure, adhesive interconnects, and viscoelasticity. Useful progr

  9. Displaced patella fractures.

    Science.gov (United States)

    Della Rocca, Gregory J

    2013-10-01

    Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  10. Design and manufacture of an ultrasonic inspection device for the friction welds in reactor vessel control rod drive mechanism housings

    International Nuclear Information System (INIS)

    Cieslav, C.; Peteuil, M.

    1985-01-01

    The control rod drive mechanism housings of a PWR reactor vessel consist of a stainless steel flange and a Ni-Cr-Fe alloy tube, assembled by friction welding. The properties of the interface and the nature of the adjacent materials require the development of a specific ultrasonic inspection technique which could be easily automated, considering the number of parts involved (77 parts per 1300 MWe reactor vessel). The part has the general shape of a tube (inside diameter: 70 mm, outside diameter: 103 mm). The transition between both forged parent materials (stainless steel/Ni-Cr-Fe alloy) is obtained by a very thin interface, whose general orientation is normal to the tube centerline. The heat affected zone has generally a coarser and more irregular structure than that observed in the parent materials. The design and development were carried out using a prototype machine on test-pieces representative of a control rod drive mechanism housing, and containing the following artificial reflectors: notches obtained by electro-discharge machining on the inside and outside surfaces, on each side of the interface; planar artificial defects, parallel to the interface. These defects, obtained from 2 flat bottomed holes, drilled into the mock-up constituent parts, were conveyed to the interface during friction welding

  11. Hydraulic Circuit of Mechanical Pruner Drive for Hops on Low Trellises

    Directory of Open Access Journals (Sweden)

    Hoffmann David

    2015-09-01

    Full Text Available A mechanical pruner serves for pruning new hopvine shoots in spring. The later yield depends on the right timing and quality of pruning. That is why hop pruning is one of the most important agrotechnical procedures. A double-disc mechanical pruner used on high trellises cannot be used on low trellises due to its large size. Abroad, for pruning hops on low trellises a specially adapted sprinkler is used (chemical pruning. With regard to the effort to minimize the chemical environmental burden, we opted for the design of the mechanical pruner. Firstly, the low trellis, mechanical pruner, and also elements used in the design of hydraulic circuit are described. Next part of the paper is devoted to the input requirements for both the hydraulic circuit and the mechanical pruner designs. Then a description of an adapted inter-axle carrier used for the experimental model of the hop mechanical pruner and of the effected field measurement follows, along with interpretation of the measured data. These data are depicted in clearly arranged graphs showing the dependency of pressure and hydraulic oil flow on the cutting disc rotational frequency.

  12. Aging mechanisms in the Westinghouse PWR [Pressurized Water Reactor] Control Rod Drive system

    International Nuclear Information System (INIS)

    Gunther, W.; Sullivan, K.

    1991-01-01

    An aging assessment of the Westinghouse Pressurized Water Reactor (PWR) Control Rod System (CRD) has been completed as part of the US NRC's Nuclear Plant Aging Research, (NPAR) Program. This study examined the design, construction, maintenance, and operation of the system to determine its potential for degradation as the plant ages. Selected results from this study are presented in this paper. The operating experience data were evaluated to identify the predominant failure modes, causes, and effects. From our evaluation of the data, coupled with an assessment of the materials of construction and the operating environment, we conclude that the Westinghouse CRD system is subject to degradation which, if unchecked, could affect its safety function as a plant ages. Ways to detect and mitigate the effects of aging are included in this paper. The current maintenance for the control rod drive system at fifteen Westinghouse PWRs was obtained through a survey conducted in cooperation with EPRI and NUMARC. The results of the survey indicate that some plants have modified the system, replaced components, or expanded preventive maintenance. Several of these activities have effectively addressed the aging issue. 2 refs., 2 figs., 2 tabs

  13. Smac mimetics and oncolytic viruses synergize in driving anticancer T-cell responses through complementary mechanisms.

    Science.gov (United States)

    Kim, Dae-Sun; Dastidar, Himika; Zhang, Chunfen; Zemp, Franz J; Lau, Keith; Ernst, Matthias; Rakic, Andrea; Sikdar, Saif; Rajwani, Jahanara; Naumenko, Victor; Balce, Dale R; Ewanchuk, Ben W; Taylor, Pankaj; Yates, Robin M; Jenne, Craig; Gafuik, Chris; Mahoney, Douglas J

    2017-08-24

    Second mitochondrial activator of caspase (Smac)-mimetic compounds and oncolytic viruses were developed to kill cancer cells directly. However, Smac-mimetic compound and oncolytic virus therapies also modulate host immune responses in ways we hypothesized would complement one another in promoting anticancer T-cell immunity. We show that Smac-mimetic compound and oncolytic virus therapies synergize in driving CD8 + T-cell responses toward tumors through distinct activities. Smac-mimetic compound treatment with LCL161 reinvigorates exhausted CD8 + T cells within immunosuppressed tumors by targeting tumor-associated macrophages for M1-like polarization. Oncolytic virus treatment with vesicular stomatitis virus (VSV ΔM51 ) promotes CD8 + T-cell accumulation within tumors and CD8 + T-cell activation within the tumor-draining lymph node. When combined, LCL161 and VSV ΔM51 therapy engenders CD8 + T-cell-mediated tumor control in several aggressive mouse models of cancer. Smac-mimetic compound and oncolytic virus therapies are both in clinical development and their combination therapy represents a promising approach for promoting anticancer T-cell immunity.Oncolytic viruses (OV) and second mitochondrial activator of caspase (Smac)-mimetic compounds (SMC) synergistically kill cancer cells directly. Here, the authors show that SMC and OV therapies combination also synergize in vivo by promoting anticancer immunity through an increase in CD8 + T-cell response.

  14. Converging Mechanisms of p53 Activation Drive Motor Neuron Degeneration in Spinal Muscular Atrophy.

    Science.gov (United States)

    Simon, Christian M; Dai, Ya; Van Alstyne, Meaghan; Koutsioumpa, Charalampia; Pagiazitis, John G; Chalif, Joshua I; Wang, Xiaojian; Rabinowitz, Joseph E; Henderson, Christopher E; Pellizzoni, Livio; Mentis, George Z

    2017-12-26

    The hallmark of spinal muscular atrophy (SMA), an inherited disease caused by ubiquitous deficiency in the SMN protein, is the selective degeneration of subsets of spinal motor neurons. Here, we show that cell-autonomous activation of p53 occurs in vulnerable but not resistant motor neurons of SMA mice at pre-symptomatic stages. Moreover, pharmacological or genetic inhibition of p53 prevents motor neuron death, demonstrating that induction of p53 signaling drives neurodegeneration. At late disease stages, however, nuclear accumulation of p53 extends to resistant motor neurons and spinal interneurons but is not associated with cell death. Importantly, we identify phosphorylation of serine 18 as a specific post-translational modification of p53 that exclusively marks vulnerable SMA motor neurons and provide evidence that amino-terminal phosphorylation of p53 is required for the neurodegenerative process. Our findings indicate that distinct events induced by SMN deficiency converge on p53 to trigger selective death of vulnerable SMA motor neurons. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  15. Epigenetic Mechanisms in Bone Biology and Osteoporosis: Can They Drive Therapeutic Choices?

    Science.gov (United States)

    Marini, Francesca; Cianferotti, Luisella; Brandi, Maria Luisa

    2016-08-12

    Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2), the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs). Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine's principles.

  16. Evidence of two distinct mechanisms driving photoinduced matter motion in thin films containing azobenzene derivatives.

    Science.gov (United States)

    Fabbri, F; Garrot, D; Lahlil, K; Boilot, J P; Lassailly, Y; Peretti, J

    2011-02-17

    Photoinduced matter motion in thin films containing azobenzene derivatives grafted to a polymer backbone is investigated by means of near-field probe microscopy. We evidence the existence of two different photomechanical processes which produce mass transport. One is governed by the light intensity pattern and the other by the light polarization pattern. The intensity-driven mechanism is found to critically depend on the polymer matrix while the polarization-driven mechanism occurs with almost the same efficiency in different materials. Depending on the relationship between the polarization and intensity patterns, the two processes may either compete or cooperate giving rise to a nontrivial directional mass transport process.

  17. Modeling of primary water stress corrosion cracking at control rod drive mechanism nozzles of pressurized water reactors

    International Nuclear Information System (INIS)

    Aly, Omar Fernandes

    2006-01-01

    One of the main failure mechanisms that cause risks to pressurized water reactors is the primary water stress corrosion cracking (PWSCC) occurring in alloys. It can occurs, besides another places, at the control reactor displacement mechanism nozzles. It is caused by the joint effect of tensile stress, temperature, susceptible metallurgical microstructure and environmental conditions of the primary water. These cracks can cause accidents that reduce nuclear safety by blocking the rod's displacement and may cause leakage of primary water, reducing the reactor's life. In this work it is proposed a study of the existing models and a modeling proposal to primary water stress corrosion cracking in these nozzles in a nickel based Alloy 600. It is been superposed electrochemical and fracture mechanics models, and validated using experimental and literature data. The experimental data were obtained at CDTN-Brazilian Nuclear Technology Development Center, in a recent installed slow strain rate testing equipment. In the literature it is found a diagram that indicates a thermodynamic condition for the occurrence of some PWSCC sub modes in Alloy 600: it was used potential x pH diagrams (Pourbaix diagrams), for Alloy 600 in high temperature primary water (300 deg C till 350 deg C). Over it, were located the PWSCC sub modes, using experimental data. It was added a third parameter called 'stress corrosion strength fraction'. However, it is possible to superpose to this diagram, other parameters expressing PWSCC initiation or growth kinetics from other models. Here is the proposition of the original contribution of this work: from an original experimental condition of potential versus pH, it was superposed, an empiric-comparative, a semi-empiric-probabilistic, an initiation time, and a strain rate damage models, to quantify respectively the PWSCC susceptibility, the failure time, and in the two lasts, the initiation time of stress corrosion cracking. It was modeling from our

  18. A literature review of empirical studies of philanthropy : eight mechanisms that drive charitable giving.

    NARCIS (Netherlands)

    Bekkers, René; Wiepking, Pamala

    2010-01-01

    The authors present an overview of the academic literature on charitable giving based on a literature review of more than 500 articles. They structure their review around the central question of why people donate money to charitable organizations. We identify eight mechanisms as the most important

  19. Physiological mechanisms of dyspnea during exercise with external thoracic restriction: Role of increased neural respiratory drive

    Science.gov (United States)

    Mendonca, Cassandra T.; Schaeffer, Michele R.; Riley, Patrick

    2013-01-01

    We tested the hypothesis that neuromechanical uncoupling of the respiratory system forms the mechanistic basis of dyspnea during exercise in the setting of “abnormal” restrictive constraints on ventilation (VE). To this end, we examined the effect of chest wall strapping (CWS) sufficient to mimic a “mild” restrictive lung deficit on the interrelationships between VE, breathing pattern, dynamic operating lung volumes, esophageal electrode-balloon catheter-derived measures of the diaphragm electromyogram (EMGdi) and the transdiaphragmatic pressure time product (PTPdi), and sensory intensity and unpleasantness ratings of dyspnea during exercise. Twenty healthy men aged 25.7 ± 1.1 years (means ± SE) completed symptom-limited incremental cycle exercise tests under two randomized conditions: unrestricted control and CWS to reduce vital capacity (VC) by 21.6 ± 0.5%. Compared with control, exercise with CWS was associated with 1) an exaggerated EMGdi and PTPdi response; 2) no change in the relationship between EMGdi and each of tidal volume (expressed as a percentage of VC), inspiratory reserve volume, and PTPdi, thus indicating relative preservation of neuromechanical coupling; 3) increased sensory intensity and unpleasantness ratings of dyspnea; and 4) no change in the relationship between increasing EMGdi and each of the intensity and unpleasantness of dyspnea. In conclusion, the increased intensity and unpleasantness of dyspnea during exercise with CWS could not be readily explained by increased neuromechanical uncoupling but likely reflected the awareness of increased neural respiratory drive (EMGdi) needed to achieve any given VE during exercise in the setting of “abnormal” restrictive constraints on tidal volume expansion. PMID:24356524

  20. Epigenetic Mechanisms in Bone Biology and Osteoporosis: Can They Drive Therapeutic Choices?

    Directory of Open Access Journals (Sweden)

    Francesca Marini

    2016-08-01

    Full Text Available Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2, the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs. Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine’s principles.

  1. Sex ratio meiotic drive as a plausible evolutionary mechanism for hybrid male sterility.

    Directory of Open Access Journals (Sweden)

    Linbin Zhang

    2015-03-01

    Full Text Available Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome--two patterns widely observed across animals.

  2. METHOD OF THE DRIVE POWER DETERMINATION OF THE MECHANISMS OF THE BRIDGE CRANE MOVEMENT CONSIDERING THE ROLLING FRICTION

    Directory of Open Access Journals (Sweden)

    V. M. Bohomaz

    2015-08-01

    were built. Practical value. The application of the proposed method of determining the driving power of the crane allows determining its value more precisely, taking into account the impedance of the rolling friction of the wheels on the rails with a flanged on the rails. This approach enables better selection of elements of the mechanism of the bridge crane movement.

  3. Job Displacement and Crime

    DEFF Research Database (Denmark)

    Bennett, Patrick; Ouazad, Amine

    This paper matches a comprehensive Danish employer-employee data set with individual crime information (timing of offenses, charges, convictions, and prison terms by crime type) to estimate the impact of job displacement on an individual’s propensity to commit crime. We focus on displaced...... no significantly increasing trend prior to displacement; and the crime rate of workers who will be displaced is not significantly higher than the crime rate of workers who will not be displaced. In contrast, displaced workers’ probability to commit any crime increases by 0.52 percentage points in the year of job...

  4. The role of turbulent pressure as a coherent pulsational driving mechanism: the case of the δ Scuti star HD 187547

    Energy Technology Data Exchange (ETDEWEB)

    Antoci, V.; Houdek, G.; Kjeldsen, H.; Trampedach, R.; Arentoft, T. [Stellar Astrophysics Centre, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Cunha, M. [Centro de Astrofísca e Faculdade de Ciências, Universidade do Porto, Rua das Estrelas 4150-762 (Portugal); Handler, G. [Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland); Lüftinger, T. [Institute for Astronomy, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria); Murphy, S., E-mail: antoci@phys.au.dk [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

    2014-12-01

    HD 187547 was the first candidate that led to the suggestion that solar-like oscillations are present in δ Scuti stars. Longer observations, however, show that the modes interpreted as solar-like oscillations have either very long mode lifetimes, longer than 960 days, or are coherent. These results are incompatible with the nature of 'pure' stochastic excitation as observed in solar-like stars. Nonetheless, one point is certain: the opacity mechanism alone cannot explain the oscillation spectrum of HD 187547. Here we present new theoretical investigations showing that convection dynamics can intrinsically excite coherent pulsations in the chemically peculiar δ Scuti star HD 187547. More precisely, it is the perturbations of the mean Reynold stresses (turbulent pressure) that drives the pulsations and the excitation takes place predominantly in the hydrogen ionization zone.

  5. Current drive drift waves as a possible mechanism for dynamo effect and transport in reversed field pinches

    International Nuclear Information System (INIS)

    Briguglio, S.; Romanelli, F.; Vlad, G.

    1986-01-01

    The possibility that a current driven drift wave turbulence may be responsible for the outward ion flux observed in Reversed Field Pinches (RFPs) is investigated; the latter flux was recently proposed as the driving mechanism of the dynamo sustaining the poloidal current in the external region of an RFP discharge. It is shown that this possibility can be supported by the linear theory of current driven drift waves. Finally, on the assumption that the transport is dominated by these instabilities, a scaling law for the temperature in RFPs is derived, which shows an approximately linear dependence on the current and a weak dependence on the size of the machine, in agreement with the experimental results. (author)

  6. [Shifting path of industrial pollution gravity centers and its driving mechanism in Pan-Yangtze River Delta].

    Science.gov (United States)

    Zhao, Hai-Xia; Jiang, Xiao-Wei; Cui, Jian-Xin

    2014-11-01

    Shifting path of industrial pollution gravity centers is the response of environmental special formation during the industry transfer process, in order to prove the responding of industrial pollution gravity centers to industry transfer in economically developed areas, this paper calculates the gravity centers of industrial wastewater, gas and solid patterns and reveals the shifting path and its driving mechanism, using the data of industrial pollution in the Pan-Yangtze River Delta from 2000 to 2010. The results show that the gravity center of the industrial waste in Pan-Yangtze River Delta shifts for sure in the last 10 years, and gravity center of solid waste shifts the maximum distance within the three wastes, which was 180.18 km, and shifting distances for waste gas and waste water were 109.51 km and 85.92 km respectively. Moreover, the gravity center of the industrial waste in Pan-Yangtze River Delta shifts westwards, and gravity centers of waste water, gas and solid shift for 0.40 degrees, 0.17 degrees and 0.03 degrees respectively. The shifting of industrial pollution gravity centers is driven by many factors. The rapid development of the heavy industry in Anhui and Jiangxi provinces results in the westward shifting of the pollutions. The optimization and adjustment of industrial structures in Yangtze River Delta region benefit to alleviating industrial pollution, and high-polluting industries shifted to Anhui and Jiangxi provinces promotes pollution gravity center shifting to west. While the development of massive clean enterprise, strong environmental management efforts and better environmental monitoring system slow the shifting trend of industrial pollution to the east in Yangtze River Delta. The study of industrial pollution gravity shift and its driving mechanism provides a new angle of view to analyze the relationship between economic development and environmental pollution, and also provides academic basis for synthetical management and control of

  7. Customizing the coefficients of urban domestic pollutant discharge and their driving mechanisms: Evidence from the Taihu Basin, China.

    Science.gov (United States)

    Zhao, Haixia; Cui, Jianxin; Wang, Shufen; Lindley, Sarah

    2018-05-01

    Discharge of urban domestic pollution has risen sharply during China's extensive urbanization. Together with understanding the complexity of influencing factors underpinning this rise, it has become a pressing issue to estimate total discharge and illustrate its driving mechanism scientifically. This paper reports on the monitoring of discharge from 36 sampling sites in selected residential districts in the heavily polluted Taihu Basin, China. The data were used to estimate the total amount of discharge, to develop corresponding urban domestic pollutant discharge coefficients and to analyse associated spatial patterns. Data from a questionnaire survey of over 1000 households in downtown, suburb and market town areas were then used to apply an econometric model in order to distinguish driving mechanisms. The urban domestic pollutant discharge coefficients developed in this paper are generally smaller than those reported nationally for China, based on more generalised data, decaying from city centres to the urban periphery. This study quantifies the amount of discharge and also demonstrates that urban domestic pollutant discharge is driven by multiple factors. For example, urban domestic pollution discharge rates were positively correlated with income and female-dominated households also tend to discharge more wastewater. Other factors were found to have negative correlations, such as sewage treatment rates, awareness of environmental protection, age and degree of education. As well as providing new and refined data on urban pollution discharge characteristics, the research in this paper also demonstrates the utility of combining household questionnaire and sample monitoring data in order to yield greater insights into the causes of typical polluting behaviour in Chinese neighbourhoods. Copyright © 2017. Published by Elsevier Ltd.

  8. Traditional medicines as a mechanism for driving research innovation in Africa

    Directory of Open Access Journals (Sweden)

    Holtel Andreas

    2011-03-01

    Full Text Available Abstract The outcomes from recent high profile deliberations concerning African health research and economic development all point towards the need for a mechanism to support health innovation on the continent. The mission of the African Network for Drugs and Diagnostics Innovation (ANDI, is to promote and sustain African-led health product innovation to address African public health needs through the assembly of research networks, and building of capacity to support human and economic development. ANDI is widely viewed as the vehicle to implementing some of these recommendations. There is tremendous opportunity for Africa, to leverage the expertise in natural products and traditional medicines in support of this objective to kick-start innovation. This report highlights key recommendations that have emerged through expert forums convened by ANDI on the challenges, opportunities and prospects for investing in this important area of research.

  9. Functional composition drives ecosystem function through multiple mechanisms in a broadleaved subtropical forest.

    Science.gov (United States)

    Chiang, Jyh-Min; Spasojevic, Marko J; Muller-Landau, Helene C; Sun, I-Fang; Lin, Yiching; Su, Sheng-Hsin; Chen, Zueng-Sang; Chen, Chien-Teh; Swenson, Nathan G; McEwan, Ryan W

    2016-11-01

    Understanding the role of biodiversity (B) in maintaining ecosystem function (EF) is a foundational scientific goal with applications for resource management and conservation. Two main hypotheses have emerged that address B-EF relationships: niche complementarity (NC) and the mass-ratio (MR) effect. We tested the relative importance of these hypotheses in a subtropical old-growth forest on the island nation of Taiwan for two EFs: aboveground biomass (ABG) and coarse woody productivity (CWP). Functional dispersion (FDis) of eight plant functional traits was used to evaluate complementarity of resource use. Under the NC hypothesis, EF will be positively correlated with FDis. Under the MR hypothesis, EF will be negatively correlated with FDis and will be significantly influenced by community-weighted mean (CWM) trait values. We used path analysis to assess how these two processes (NC and MR) directly influence EF and may contribute indirectly to EF via their influence on canopy packing (stem density). Our results indicate that decreasing functional diversity and a significant influence of CWM traits were linked to increasing AGB for all eight traits in this forest supporting the MR hypothesis. Interestingly, CWP was primarily influenced by NC and MR indirectly via their influence on canopy packing. Maximum height explained more of the variation in both AGB and CWP than any of the other plant functional traits. Together, our results suggest that multiple mechanisms operate simultaneously to influence EF, and understanding their relative importance will help to elucidate the role of biodiversity in maintaining ecosystem function.

  10. Synoptic-scale analysis of mechanisms driving surface chlorophyll dynamics in the North Atlantic

    Directory of Open Access Journals (Sweden)

    A. S. A. Ferreira

    2015-06-01

    Full Text Available Several hypotheses have been proposed for the onset of the spring phytoplankton bloom in the North Atlantic. Our main objective is to examine which bottom-up processes can best predict the annual increase in surface phytoplankton concentration in the North Atlantic by applying novel phenology algorithms to ocean colour data. We construct indicator fields and time series which, in various combinations, provide models consistent with the principle dynamics previously proposed. Using a multimodel inference approach, we investigate the evidence supporting these models and how it varies in space. We show that, in terms of bottom-up processes alone, there is a dominant physical mechanism, namely mixed-layer shoaling, that best predicts the interannual variation in the initial increase in surface chlorophyll across large sectors of the North Atlantic. We further show that different regions are governed by different physical phenomena and that wind-driven mixing is a common component, with either heat flux or light as triggers. We believe these findings to be relevant to the ongoing discussion on North Atlantic bloom onset.

  11. Is mitochondrial dysfunction a driving mechanism linking COPD to nonsmall cell lung carcinoma?

    Directory of Open Access Journals (Sweden)

    Francois Ng Kee Kwong

    2017-10-01

    Full Text Available Chronic obstructive pulmonary disease (COPD patients are at increased risk of developing nonsmall cell lung carcinoma, irrespective of their smoking history. Although the mechanisms behind this observation are not clear, established drivers of carcinogenesis in COPD include oxidative stress and sustained chronic inflammation. Mitochondria are critical in these two processes and recent evidence links increased oxidative stress in COPD patients to mitochondrial damage. We therefore postulate that mitochondrial damage in COPD patients leads to increased oxidative stress and chronic inflammation, thereby increasing the risk of carcinogenesis. The functional state of the mitochondrion is dependent on the balance between its biogenesis and degradation (mitophagy. Dysfunctional mitochondria are a source of oxidative stress and inflammasome activation. In COPD, there is impaired translocation of the ubiquitin-related degradation molecule Parkin following activation of the Pink1 mitophagy pathway, resulting in excessive dysfunctional mitochondria. We hypothesise that deranged pathways in mitochondrial biogenesis and mitophagy in COPD can account for the increased risk in carcinogenesis. To test this hypothesis, animal models exposed to cigarette smoke and developing emphysema and lung cancer should be developed. In the future, the use of mitochondria-based antioxidants should be studied as an adjunct with the aim of reducing the risk of COPD-associated cancer.

  12. Displacement characteristics of a piezoactuator-based prototype microactuator with a hydraulic displacement amplification system

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhara [NMAMIT, Nitte (India); Rao, Rathnamala [NITK, Surathkal (India)

    2015-11-15

    In this study, a new piezoactuator-based prototype microactuator is proposed with a hydraulic displacement amplification system. A piezoactuator is used to deflect a diaphragm which displaces a certain volume of hydraulic fluid into a smaller-diameter piston chamber, thereby amplifying the displacement at the other end of the piston. An electro-mechanical model is implemented to estimate the displacement of a multilayer piezoelectric actuator for the applied input voltage considering the hysteresis behavior. The displacement characteristics of the proposed microactuator are studied for triangular actuation voltage signal. Results of the experiments and simulation of the displacement behavior of the stacked piezoactuator and the amplified displacement of the prototype actuator were compared. Experimental results suggest that the mathematical model developed for the new piezoactuator-based prototype actuator is capable of estimating its displacement behavior accurately, within an error of 1.2%.

  13. Melanoregulin regulates a shedding mechanism that drives melanosome transfer from melanocytes to keratinocytes.

    Science.gov (United States)

    Wu, Xufeng S; Masedunskas, Andreas; Weigert, Roberto; Copeland, Neal G; Jenkins, Nancy A; Hammer, John A

    2012-07-31

    Mammalian pigmentation is driven by the intercellular transfer of pigment-containing melanosomes from the tips of melanocyte dendrites to surrounding keratinocytes. Tip accumulation of melanosomes requires myosin Va, because melanosomes concentrate in the center of melanocytes from myosin Va-null (dilute) mice. This distribution defect results in inefficient melanosome transfer and a dilution of coat color. Dilute mice that simultaneously lack melanoregulin, the product of the dilute suppressor locus, exhibit a nearly complete restoration of coat color, but, surprisingly, melanosomes remain concentrated in the center of their melanocytes. Here we show that dilute/dsu melanocytes, but not dilute melanocytes, readily transfer the melanosomes concentrated in their center to surrounding keratinocytes in situ. Using time-lapse imaging of WT melanocyte/keratinocyte cocultures in which the plasma membranes of the two cells are marked with different colors, we define an intercellular melanosome transfer pathway that involves the shedding by the melanocyte of melanosome-rich packages, which subsequently are phagocytosed by the keratinocyte. Shedding, which occurs primarily at dendritic tips but also from more central regions, involves adhesion to the keratinocyte, thinning behind the forming package, and apparent self-abscission. Finally, we show that shedding from the cell center is sixfold more frequent in cultured dilute/dsu melanocytes than in dilute melanocytes, consistent with the in situ data. Together, these results explain how dsu restores the coat color of dilute mice without restoring intracellular melanosome distribution, indicate that melanoregulin is a negative regulator of melanosome transfer, and provide insight into the mechanism of intercellular melanosome transfer.

  14. A Modified Model Reference Adaptive Control for a Single Motor of Latch Type Control Element Drive Mechanism

    International Nuclear Information System (INIS)

    Park, Bae Jeong

    2016-01-01

    A modified Model Reference Adaptive Control (MRAC) for a single motor of latch type Control Element Drive Mechanism (CEDM) is described herein. The CEDM has complicated dynamic characteristics including electrical, mechanical, and magnetic effects. The previous control system has utilized a Proportional-Integral (PI) controller, and the control performance is limited according to nonlinear dynamic characteristics and environmental conditions. The modified MRAC using system identification (ID) technique improves the control performance in the operating condition such as model parameter variation and environmental condition change. The modified MRAC using the identified reference model with feed-forward gain and 180Hz noise reduction filter presents better performance under normal and/or abnormal condition. The simplified reference model can make H/W implementation more practical on the viewpoint of less computation and good performance. Actually, the CEDM controller shall be capable of controlling 101 control element assemblies (CEAs) individually in the nuclear power plant. Because the load conditions and the environmental condition around the 101 CEAs are all different minutely, the proposed modified MRAC can be a good practice. The modified MRAC controller will be applied in the real nuclear power plant later and this will overcome some weak point of PI controller

  15. Design, Fabrication, and Characteristic Experiment of a Hybrid Electromagnet for Bottom-mounted Control Rod Drive Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Hyung; Lee, Jin-Haeng; Yoo, Yeon-Sik; Cho, Yeong-Garp; Ryu, Jeong-Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    A control rod drive mechanism (CRDM) is located in the reactor pool top (Top-mounted) or a reactivity control mechanism room under the reactor pool bottom (Bottom-mounted). The function of the CRDM is to insert, withdraw, or maintain neutron absorbing material at any required position in the reactor core in order to keep reactivity control of the core. There are so many kinds of CRDMs, such as magnetic-jack type, hydraulic type, rack and pinion type, chain type, and linear or rotary step motor and so on. As a part of a new project, we have completed the design, fabrication, and characteristic experiment of the prototype bottom-mounted CRDM (BMCRDM). The measured carrying capacity of proto-type hybrid electromagnet is approximately 2.8 (kgf) larger than that of 3D-FEM result. The major reasons of the disagreement between the measured and calculated results are as follows. A. B-H Curve differences of ferromagnetic materials B. Fabrication tolerance and the measured maximum temperature at the center of winding for proto-type hybrid electromagnet, 106 .deg. C, appeared to be 5 .deg. C higher than the analytical result. The major reasons of the disagreement between the measured and calculated results are as follows. A. Difficult for exact modeling of winding including impregnated epoxy, coil insulator, and isolator.

  16. METHOD FOR CALCULATION OF DISPLACEMENT FIELDS AND STRESSES IN SYSTEM OF PARALLEL LENTICULAR MECHANICAL TWINS OCCURRING IN MARTENSITIC PHASE OF Ni2MnGa-MAGNETIC ALLOY HAVING PROPERTY OF SHAPE MEMORY

    Directory of Open Access Journals (Sweden)

    E. V. Shmatok

    2015-01-01

    Full Text Available Nowadays mathematical modeling of peculiar features of a stress-strain state is considered as a perspective direction of research. In this regard the aim of this paper has been to make calculations of the stress-strain state initiated by a system of parallel lenticular residual mechanical twins that occur due to local surface deformation of  Ni2MnGa single crystal martensitic phase.The method is applied while using a superposition principle of fields and approximation of a continuous distribution of twinning dislocations on twin boundaries in a continuous elastic medium.The calculations have made it possible to obtain distribution graphs of displacement fields and stresses and point out the fact that a configuration of displacement component distribution uy is significantly different from the displacement of components ux and uz having a displacement distribution similar to each other. The highest value of displacement occurs in the component uy in twins peaks.The paper also presents results of calculations for six components of a stress field the tensor. The obtained results have revealed similarity in stress distribution character of the components  sxz and szz, but they differ numerically from each other about in two times. The largest value of the stresses occurring in the lenticular twins has been observed in components sxx, sxz, syy, syz and it has been focused mainly at the borders and peaks  of twins.A common feature of the obtained components of displacement and stresses in a lenticular twins system is symmetry with regard to OY. In addition, the stress distribution of all obtained tensor components has been mainly localized at the borders and at the tops of twins where the highest values of stresses capable of exerting a significant impact on dislocation and diffusion processes are generally concentrated.

  17. Modeling and analysis of hydraulic dashpot for impact free operation in a shut-off rod drive mechanism

    Directory of Open Access Journals (Sweden)

    Narendra K. Singh

    2016-09-01

    Full Text Available Rotary hydraulic dashpot used for shut-off rod drive mechanism application of a nuclear reactor has been studied in this paper for impact free operation. The rotary hydraulic dashpot has been modeled as a system with 1 degree of freedom (DOF and the simulation results are experimentally validated. The dashpot is modeled as a hinge joint with moving and fixed vanes as rigid bodies. Shut-off rods are used to shut-down a nuclear reactor and hydraulic dashpot absorbs the energy of freely falling shut-off rod at the end of rod travel. With the increase in the environmental temperature the dashpot becomes underdamped at a point because of reduction in the viscosity of oil and results into impact on mechanism components. Hydraulic dashpot designs are finalized with an optimum combination of dashpot clearances and oil viscosity to meet the drop time criterion and impact free operation at room temperature as well as at elevated temperature. Also with the change in mechanical loads the dashpot becomes underdamped. So the study is further extended to see the effects of various parameters such as moment of inertia, constraint angle and applied moment on the dashpot. Study is focused on obtaining dashpot responses in terms of relative rotation, relative angular velocity and relative angular acceleration at various environmental temperatures. Finite element commercial code COMSOL Multiphysics 5.1 has been used for numerical simulations. Equations for both rigid body dynamics and heat transfer in solids are solved simultaneously. Thus, energy absorbed and local temperature rise in the dashpot operation is also obtained. Both simulation and experimental results at wide range of environmental temperature are presented and compared in this paper. This study forms a good tool to design a hydraulic dashpot, which gives impact free operation in a shut-off rod free fall.

  18. Modal space three-state feedback control for electro-hydraulic servo plane redundant driving mechanism with eccentric load decoupling.

    Science.gov (United States)

    Zhao, Jinsong; Wang, Zhipeng; Zhang, Chuanbi; Yang, Chifu; Bai, Wenjie; Zhao, Zining

    2018-04-13

    The shaking table based on electro-hydraulic servo parallel mechanism has the advantage of strong carrying capacity. However, the strong coupling caused by the eccentric load not only affects the degree of freedom space control precision, but also brings trouble to the system control. A novel decoupling control strategy is proposed, which is based on modal space to solve the coupling problem for parallel mechanism with eccentric load. The phenomenon of strong dynamic coupling among degree of freedom space is described by experiments, and its influence on control design is discussed. Considering the particularity of plane motion, the dynamic model is built by Lagrangian method to avoid complex calculations. The dynamic equations of the coupling physical space are transformed into the dynamic equations of the decoupling modal space by using the weighted orthogonality of the modal main mode with respect to mass matrix and stiffness matrix. In the modal space, the adjustments of the modal channels are independent of each other. Moreover, the paper discusses identical closed-loop dynamic characteristics of modal channels, which will realize decoupling for degree of freedom space, thus a modal space three-state feedback control is proposed to expand the frequency bandwidth of each modal channel for ensuring their near-identical responses in a larger frequency range. Experimental results show that the concept of modal space three-state feedback control proposed in this paper can effectively reduce the strong coupling problem of degree of freedom space channels, which verify the effectiveness of the proposed model space state feedback control strategy for improving the control performance of the electro-hydraulic servo plane redundant driving mechanism. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Host Acceptance and Larval Competition between the Invasive Banded and European Elm Bark Beetles, Scolytus schevyrewi and S. multistriatus (Coleoptera: Scolytidae): Potential Mechanisms for Competitive Displacement

    Science.gov (United States)

    A recent survey revealed that the newly invasive banded elm bark beetle, Scolytus schevyrewi, was much more abundant than the long-established European elm bark beetle, S. multistriatus, in areas of Colorado and Wyoming, USA. This study sought to determine whether competitive displacement of S. mul...

  20. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  1. Modeling Displacement Measurement using Vibration Transducers

    Directory of Open Access Journals (Sweden)

    AGOSTON Katalin

    2014-05-01

    Full Text Available This paper presents some aspects regarding to small displacement measurement using vibration transducers. Mechanical faults, usages, slackness’s, cause different noises and vibrations with different amplitude and frequency against the normal sound and movement of the equipment. The vibration transducers, accelerometers and microphone are used for noise and/or sound and vibration detection with fault detection purpose. The output signal of the vibration transducers or accelerometers is an acceleration signal and can be converted to either velocity or displacement, depending on the preferred measurement parameter. Displacement characteristics are used to indicate when the machine condition has changed. There are many problems using accelerometers to measure position or displacement. It is important to determine displacement over time. To determinate the movement from acceleration a double integration is needed. A transfer function and Simulink model was determinate for accelerometers with capacitive sensing element. Using these models the displacement was reproduced by low frequency input.

  2. Balanced Motions Realization for a Mechanical Regulators Free and Front-Wheel Drive Bicycle Robot Under Zero Forward Speed

    Directory of Open Access Journals (Sweden)

    Yonghua Huang

    2013-08-01

    Full Text Available This paper focuses on a mechanical regulator free and front- wheel drive bicycle robot. We present a scheme to achieve the robot's track-stand motion and circular motion under zero forward speed. In a situation where the robot's front-bar is locked at 90 degrees, a kinetic constraint about the rotating rate of the front-wheel and the yawing rate of the frame is derived. Using the constraint as a basis, we developed a simplified model of two independent velocities for the robot. The model suggests there is an under-actuated rolling angle in the system. Our control strategy originates from the under- actuated characteristics of the robot system. Concretely, we linearize the rolling angle of the frame and set the bicycle robot to regulate its tilting by rotating the front-wheel. In the track-stand motion, we control the position and the rotational rate of the front-wheel; but in the circular motion, only the rotational rate of the front-wheel is strictly regulated. Both simulations and physical experiments results show that our strategy is effective for achieving these two motions.

  3. Laser Ultrasonic System for Surface Crack Visualization in Dissimilar Welds of Control Rod Drive Mechanism Assembly of Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Yun-Shil Choi

    2014-01-01

    Full Text Available In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI technology. A full-scale control rod drive mechanism (CRDM assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the crack were possible by ultrasonic wave propagation imaging. Furthermore, ultrasonic spectral imaging unveiled frequency components of damage-induced waves, while wavelet-transformed ultrasonic propagation imaging enhanced damage visibility by generating a wave propagation video focused on the frequency component of the damage-induced waves. Dual-directional anomalous wave propagation imaging with adjacent wave subtraction was also developed to enhance the crack visibility regardless of crack orientation and wave propagation direction. In conclusion, the full-scale specimen test demonstrated that the multiple damage visualization tools are very effective in the visualization of J-groove dissimilar weld cracks.

  4. Mechanical characteristics of a double-fed machine in asynchronous mode and prospects of its application in the electric drive of mining machines

    Science.gov (United States)

    Ostrovlyanchik, V. Yu; Popolzin, I. Yu; Kubarev, V. A.; Marshev, D. A.

    2017-09-01

    The concept of a double-fed machine as an asynchronous motor with a phase rotor and a source of additional voltage is defined. Based on the analysis of a circuit replacing the double-fed machine, an expression is derived relating the moment, slip, amplitude and phase of additional voltage across the rotor. The conditions maximizing the moment with respect to amplitude and phase of additional voltage in the rotor circuit are also obtained, the phase surface of function of machine electromagnetic moment is constructed. The analysis of basic equation of electric drive motion in relation to electric drive of mine hoisting installations and the conclusion about the necessity of work in all four quadrants of coordinate plane “moment-slip” are made. Family of mechanical characteristics is constructed for a double-fed machine and its achievable speed control range in asynchronous mode is determined. Based on the type of mechanical characteristics and the calculated range of speed control, the conclusion is made about the suitability of using a dual-fed asynchronous machine for driving mine mechanisms with a small required speed control range and the need for organizing a combined operating mode for driving mine hoisting installations and other mechanisms with a large speed control range.

  5. High speed control of electro-mechanical transduction Advanced Drive Techniques for Optimized Step-and-Settle Response of MEMS Micromirrors

    OpenAIRE

    Imboden, Matthias; Chang, Jackson; Pollock, Corey; Lowell, Evan; Akbulut, Mehmet; Morrison, Jessica; Stark, Thomas; Bifano, Thomas G.; Bishop, David J.

    2015-01-01

    Micro/Nano Electro Mechanical Systems (MEMS/NEMS) provide the engineer with a powerful set of solutions to a wide variety of technical challenges. However, because they are mechanical systems, response times can be a limitation. In some situations, advanced engineered drive techniques can improve response times by as much as a thousand, significantly opening up the application space for MEMS/NEMS solutions.

  6. Impact of Different Ventilation Strategies on Driving Pressure, Mechanical Power, and Biological Markers During Open Abdominal Surgery in Rats.

    Science.gov (United States)

    Maia, Lígia de A; Samary, Cynthia S; Oliveira, Milena V; Santos, Cintia L; Huhle, Robert; Capelozzi, Vera L; Morales, Marcelo M; Schultz, Marcus J; Abreu, Marcelo G; Pelosi, Paolo; Silva, Pedro L; Rocco, Patricia Rieken Macedo

    2017-10-01

    Intraoperative mechanical ventilation may yield lung injury. To date, there is no consensus regarding the best ventilator strategy for abdominal surgery. We aimed to investigate the impact of the mechanical ventilation strategies used in 2 recent trials (Intraoperative Protective Ventilation [IMPROVE] trial and Protective Ventilation using High versus Low PEEP [PROVHILO] trial) on driving pressure (ΔPRS), mechanical power, and lung damage in a model of open abdominal surgery. Thirty-five Wistar rats were used, of which 28 were anesthetized, and a laparotomy was performed with standardized bowel manipulation. Postoperatively, animals (n = 7/group) were randomly assigned to 4 hours of ventilation with: (1) tidal volume (VT) = 7 mL/kg and positive end-expiratory pressure (PEEP) = 1 cm H2O without recruitment maneuvers (RMs) (low VT/low PEEP/RM-), mimicking the low-VT/low-PEEP strategy of PROVHILO; (2) VT = 7 mL/kg and PEEP = 3 cm H2O with RMs before laparotomy and hourly thereafter (low VT/moderate PEEP/4 RM+), mimicking the protective ventilation strategy of IMPROVE; (3) VT = 7 mL/kg and PEEP = 6 cm H2O with RMs only before laparotomy (low VT/high PEEP/1 RM+), mimicking the strategy used after intubation and before extubation in PROVHILO; or (4) VT = 14 mL/kg and PEEP = 1 cm H2O without RMs (high VT/low PEEP/RM-), mimicking conventional ventilation used in IMPROVE. Seven rats were not tracheotomized, operated, or mechanically ventilated, and constituted the healthy nonoperated and nonventilated controls. Low VT/moderate PEEP/4 RM+ and low VT/high PEEP/1 RM+, compared to low VT/low PEEP/RM- and high VT/low PEEP/RM-, resulted in lower ΔPRS (7.1 ± 0.8 and 10.2 ± 2.1 cm H2O vs 13.9 ± 0.9 and 16.9 ± 0.8 cm H2O, respectively; Pmechanical power (63 ± 7 and 79 ± 20 J/min vs 110 ± 10 and 120 ± 20 J/min, respectively; P = .007). Low VT/high PEEP/1 RM+ was associated with less alveolar collapse than low VT/low PEEP/RM- (P = .03). E-cadherin expression was higher in

  7. Displacement data assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, W. Steven [Pacific Northwest Laboratory, Richland, WA 99354 (United States); Venkataramani, Shankar [Department of Mathematics and Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721 (United States); Mariano, Arthur J. [Rosenstiel School of Marine & Atmospheric Science, University of Miami, Miami, FL 33149 (United States); Restrepo, Juan M., E-mail: restrepo@math.oregonstate.edu [Department of Mathematics, Oregon State University, Corvallis, OR 97331 (United States)

    2017-02-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information is important. While the displacement transformation is generic, here we implement it within an ensemble Kalman Filter framework and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  8. Mechanisms Driving Galling Success in a Fragmented Landscape: Synergy of Habitat and Top-Down Factors along Temperate Forest Edges.

    Directory of Open Access Journals (Sweden)

    Nina-S Kelch

    Full Text Available Edge effects play key roles in the anthropogenic transformation of forested ecosystems and their biota, and are therefore a prime field of contemporary fragmentation research. We present the first empirical study to address edge effects on the population level of a widespread galling herbivore in a temperate deciduous forest. By analyzing edge effects on abundance and trophic interactions of beech gall midge (Mikiola fagi Htg., we found 30% higher gall abundance in the edge habitat as well as lower mortality rates due to decreased top-down control, especially by parasitoids. Two GLM models with similar explanatory power (58% identified habitat specific traits (such as canopy closure and altitude and parasitism as the best predictors of gall abundance. Further analyses revealed a crucial influence of light exposure (46% on top-down control by the parasitoid complex. Guided by a conceptual framework synthesizing the key factors driving gall density, we conclude that forest edge proliferation of M. fagi is due to a complex interplay of abiotic changes and trophic control mechanisms. Most prominently, it is caused by the microclimatic regime in forest edges, acting alone or in synergistic concert with top-down pressure by parasitoids. Contrary to the prevailing notion that specialists are edge-sensitive, this turns M. fagi into a winner species in fragmented temperate beech forests. In view of the increasing proportion of edge habitats and the documented benefits from edge microclimate, we call for investigations exploring the pest status of this galling insect and the modulators of its biological control.

  9. Dementia & Driving

    Science.gov (United States)

    ... find the loss of driving privileges and the inherent loss of independence upsetting. Encourage the individual with ... to modify their driving. This can reduce the risk of an accident if the individual’s driving skills ...

  10. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  11. Actuators Using Piezoelectric Stacks and Displacement Enhancers

    Science.gov (United States)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Lee, Hyeong Jae; Walkenmeyer, Phillip; Lih, Shyh-Shiuh

    2015-01-01

    Actuators are used to drive all active mechanisms including machines, robots, and manipulators to name a few. The actuators are responsible for moving, manipulating, displacing, pushing and executing any action that is needed by the mechanism. There are many types and principles of actuation that are responsible for these movements ranging from electromagnetic, electroactive, thermo-mechanic, piezoelectric, electrostrictive etc. Actuators are readily available from commercial producers but there is a great need for reducing their size, increasing their efficiency and reducing their weight. Studies at JPL’s Non Destructive Evaluation and Advanced Actuators (NDEAA) Laboratory have been focused on the use of piezoelectric stacks and novel designs taking advantage of piezoelectric’s potential to provide high torque/force density actuation and high electromechanical conversion efficiency. The actuators/motors that have been developed and reviewed in this paper are operated by various horn configurations as well as the use of pre-stress flexures that make them thermally stable and increases their coupling efficiency. The use of monolithic designs that pre-stress the piezoelectric stack eliminates the use of compression stress bolt. These designs enable the embedding of developed solid-state motors/actuators in any structure with the only macroscopically moving parts are the rotor or the linear translator. Finite element modeling and design tools were used to determine the requirements and operation parameters and the results were used to simulate, design and fabricate novel actuators/motors. The developed actuators and performance will be described and discussed in this paper.

  12. A test research on ventilative well-distributivity under normal temperature for a control rod drive mechanism (Continuous article)

    International Nuclear Information System (INIS)

    Zhu Longxing

    1989-01-01

    A test for cooling of the control rod drive mechnism under normal temperature is described. The relationship between the unbalanced cofficient and the frictional resistance and wind velocity is found by comparing the ventilation in plate top structure of reactor with that in global top structure of reactor

  13. Research on Conflict Decision between Shift Schedule and Multienergy Management for PHEV with Automatic Mechanical Transmission under Special Driving Cycles

    Directory of Open Access Journals (Sweden)

    JunQiang Xi

    2013-01-01

    Full Text Available In order to satisfy the character of parallel hybrid electric vehicle (PHEV in some special driving cycles, a collision decision problem between the shift decision and power split ratio is proposed. Based on a large amount of experimental data the optimal decisions are determined with evidential reasoning theory. The proposed decision strategy has been verified through real road test of Chongqing public transportation line 818 and the fuel economic improvement has also been achieved.

  14. Water displacement mercury pump

    Science.gov (United States)

    Nielsen, M.G.

    1984-04-20

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  15. Internally displaced persons.

    Science.gov (United States)

    Leus, X; Wallace, J; Loretti, A

    2001-01-01

    There were estimated to be over 20 million internally displaced persons (IDPs) at the end of 1999, a number that surpasses global estimates of refugees. Displacement exposes IDPs to new hazards and accrued vulnerability. These dynamics result in greater risk for the development of illness and death. Often, access of IDPs to health care and humanitarian assistance is excluded deliberately by conflicting parties. Furthermore, the arrival of IDPs into another community or region strains local health systems, and the host population ends up sharing the sufferings of the internally displaced. Health outcomes are dismaying. From a health perspective, the best option is to avoid human displacement. WHO contributes to the prevention of displacement by working for sustainable development. Placing health high on the political agenda helps maintain stability, and thereby, reduce the likelihood for displacement. Primary responsibility for assisting IDPs, irrespective of the cause, rests with the national government. However, where the government is unwilling or unable to provide the necessary aid, the international humanitarian community must step in, with WHO playing a major role in the health sector. There is consensus among the partners of the World Health Organization (WHO) that, in emergencies, the WHO must: 1) take the lead in rapid health assessment, epidemiological and nutritional surveillance, epidemic preparedness, essential drugs management, control of communicable diseases, and physical and psychosocial rehabilitation; and 2) provide guidelines and advice on nutritional requirements and rehabilitation, immunisation, medical relief items, and reproductive health. If the vital health needs of IDPs--security, food, water, shelter, sanitation and household items--are not satisfied, the provision of health services alone cannot save lives. Community participation is essential, and community participation implies bolstering the assets and capacities of the beneficiaries.

  16. Supersymmetric Displaced Number States

    Directory of Open Access Journals (Sweden)

    Fredy R. Zypman

    2015-06-01

    Full Text Available We introduce, generate and study a family of supersymmetric displaced number states (SDNS that can be considered generalized coherent states of the supersymmetric harmonic oscillator. The family is created from the seminal supersymmetric boson-fermion entangling annihilation operator introduced by Aragone and Zypman and later expanded by Kornbluth and Zypman. Using the momentum representation, the states are obtained analytically in compact form as displaced supersymmetric number states. We study their position-momentum uncertainties, and their bunchiness by classifying them according to their Mandel Q-parameter in phase space. We were also able to find closed form analytical representations in the space and number basis.

  17. Experimental study on imbibition displacement mechanisms of two-phase fluid using micromodel: Fracture network, distribution of pore size, and matrix construction

    Science.gov (United States)

    Jafari, Iman; Masihi, Mohsen; Nasiri Zarandi, Masoud

    2017-12-01

    In this study, the effect of different parameters on the fluid transport in a fractured micromodel has been investigated. All experiments in this study have been conducted in a glass micromodel. Since the state of wetting is important in the micromodel, the wetting experiments have been conducted to determine the state of wetting in the micromodel. The used micromodel was wet by water and non-wet regarding normal decane. The fracture network, distribution of pore size, matrix construction, and injection rate are the most important parameters affecting the process. Therefore, the influence of these parameters was studied using five different patterns (A to E). The obtained results from pattern A showed that increasing water injection the flow rate results in both higher rate of imbibition and higher ultimate recovery. Pattern B, which was characterized with higher porosity and permeability, was employed to study the effect of matrix pore size distribution on the imbibition process. Compared to pattern A, a higher normal decane production was observed in this pattern. Patterns C and D were designed to understand the impact of lateral fractures on the displacement process. Higher ultimate recoveries were obtained in these patterns. A system of matrix-fracture was designed (pattern E) to evaluate water injection performance in a multi-block system. Injection of water with the flow rate of 0.01 cc/min could produce 15% of the oil available in the system. While in the test with the flow rate of 0.1 cc/min, a normal decane recovery of 0.28 was achieved.

  18. CONTROL ROD DRIVE

    Science.gov (United States)

    Chapellier, R.A.

    1960-05-24

    BS>A drive mechanism was invented for the control rod of a nuclear reactor. Power is provided by an electric motor and an outside source of fluid pressure is utilized in conjunction with the fluid pressure within the reactor to balance the loadings on the motor. The force exerted on the drive mechanism in the direction of scramming the rod is derived from the reactor fluid pressure so that failure of the outside pressure source will cause prompt scramming of the rod.

  19. Impact of Different Ventilation Strategies on Driving Pressure, Mechanical Power, and Biological Markers During Open Abdominal Surgery in Rats

    NARCIS (Netherlands)

    Maia, Lígia de A.; Samary, Cynthia S.; Oliveira, Milena V.; Santos, Cintia L.; Huhle, Robert; Capelozzi, Vera L.; Morales, Marcelo M.; Schultz, Marcus J.; Abreu, Marcelo G.; Pelosi, Paolo; Silva, Pedro L.; Rocco, Patricia Rieken Macedo

    2017-01-01

    Intraoperative mechanical ventilation may yield lung injury. To date, there is no consensus regarding the best ventilator strategy for abdominal surgery. We aimed to investigate the impact of the mechanical ventilation strategies used in 2 recent trials (Intraoperative Protective Ventilation

  20. Job Displacement and Crime

    DEFF Research Database (Denmark)

    Bennett, Patrick; Ouazad, Amine

    We use a detailed employer-employee data set matched with detailed crime information (timing of crime, fines, convictions, crime type) to estimate the impact of job loss on an individual's probability to commit crime. We focus on job losses due to displacement, i.e. job losses in firms losing...

  1. Development of ball bearing in high temperature water for in-vessel type control rod drive mechanism of advanced marine reactor

    International Nuclear Information System (INIS)

    Nunokawa, Hiroshi; Yoritsune, Tsutomu; Imayoshi, Shou; Ochiai, Masa-aki; Ishida, Toshihisa

    2001-06-01

    An advanced marine reactor MRX designed by Japan Atomic Energy Research Institute (JAERI) adopts an in-vessel type control rod drive mechanism, which is installed inside the reactor vessel. Since the in-vessel type control rod drive mechanism should work at a severe condition of a high temperature and high pressure water - 310degC and 12 MPa -, the JAERI has developed the components, a ball bearing of which especially is one of key technologies for realization of this type mechanism. The present report describes the development of the ball bearing containing a survey of materials, material screening tests on oxidation in an autoclave and rolling wear by a small facility, a trial fabrication of the full size ball bearing, and endurance test of it in the high temperature water. As a result, it was found from the development that the materials of cobalt alloy for both of the inner and outer races, cermet for the ball, and graphite for the retainer can satisfy the design condition of the ball bearing. (author)

  2. Temporal evolution and alternation of mechanisms of electric-field-induced patterns at ultralow-frequency driving.

    Science.gov (United States)

    Éber, Nándor; Palomares, Laura O; Salamon, Péter; Krekhov, Alexei; Buka, Ágnes

    2012-08-01

    The temporal evolution of patterns within the driving period of the ac voltage was studied in the 10-mHz-250-Hz frequency range. It was shown that the stationary electroconvection pattern of the conductive regime transforms into a flashing one at ultralow frequencies, existing only in narrow time windows within the period. Furthermore a transition between electroconvection and flexoelectric domains was detected which is repeating in each half period. The two patterns are well separated in time and in Fourier space. Simultaneous current measurements uncovered that the electric properties of the polyimide orienting layers influence the redistribution of the applied voltage. The experimental findings are in good qualitative agreement with the theoretical predictions based on an extended standard model including flexoelectricity.

  3. The photoelectric displacement converter

    Science.gov (United States)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  4. MODELING CONTROLLED ASYNCHRONOUS ELECTRIC DRIVES WITH MATCHING REDUCERS AND TRANSFORMERS

    Directory of Open Access Journals (Sweden)

    V. S. Petrushin

    2015-04-01

    Full Text Available Purpose. Working out of mathematical models of the speed-controlled induction electric drives ensuring joint consideration of transformers, motors and loadings, and also matching reducers and transformers, both in static, and in dynamic regimes for the analysis of their operating characteristics. Methodology. At mathematical modelling are considered functional, mass, dimensional and cost indexes of reducers and transformers that allows observing engineering and economic aspects of speed-controlled induction electric drives. The mathematical models used for examination of the transitive electromagnetic and electromechanical processes, are grounded on systems of nonlinear differential equations with nonlinear coefficients (parameters of equivalent circuits of motors, varying in each operating point, including owing to appearances of saturation of magnetic system and current displacement in a winding of a rotor of an induction motor. For the purpose of raise of level of adequacy of models a magnetic circuit iron, additional and mechanical losses are considered. Results. Modelling of the several speed-controlled induction electric drives, different by components, but working on a loading equal on character, magnitude and a demanded control range is executed. At use of characteristic families including mechanical, at various parameters of regulating on which performances of the load mechanism are superimposed, the adjusting characteristics representing dependences of a modification of electrical, energy and thermal magnitudes from an angular speed of motors are gained. Originality. The offered complex models of speed-controlled induction electric drives with matching reducers and transformers, give the chance to realize well-founded sampling of components of drives. They also can be used as the design models by working out of speed-controlled induction motors. Practical value. Operating characteristics of various speed-controlled induction electric

  5. Linear step drive

    International Nuclear Information System (INIS)

    Haniger, L.; Elger, R.; Kocandrle, L.; Zdebor, J.

    1986-01-01

    A linear step drive is described developed in Czechoslovak-Soviet cooperation and intended for driving WWER-1000 control rods. The functional principle is explained of the motor and the mechanical and electrical parts of the drive, power control, and the indicator of position are described. The motor has latches situated in the reactor at a distance of 3 m from magnetic armatures, it has a low structural height above the reactor cover, which suggests its suitability for seismic localities. Its magnetic circuits use counterpoles; the mechanical shocks at the completion of each step are damped using special design features. The position indicator is of a special design and evaluates motor position within ±1% of total travel. A drive diagram and the flow chart of both the control electronics and the position indicator are presented. (author) 4 figs

  6. Effect of Mechanical Heterogeneity on the Crack Driving Force of a Reactor Pressure Vessel Outlet Nozzle DMW Joint

    Science.gov (United States)

    Lingyan, Zhao; Yinghao, Cui; He, Xue

    2017-12-01

    The welding mechanical heterogeneity, load complexity, material and geometrical structure makes it very difficult to assess the structural integrity of dissimilar metal weld (DMW) joints. Based on a numerical simulated approach of the continuous change of material mechanical property in the buttering layer, a reactor pressure vessel (RPV) outlet nozzle DMW joint with service loads is studied, effect of mechanical heterogeneity on the stress-strain field and stress triaxiality at the semi-elliptical surface crack front are discussed. The analyses show that once the crack extends into the high hardness zone of Alloy 182 buttering, the strain decreases sharply, the strain gradient increases and the crack propagation slows down. The influence of strength mismatch on the stress triaxiality at the shallow crack front is greater than that at the deep crack front. The interaction between strength mismatch and crack depth directly affects the crack growth direction.

  7. Is competition needed for ecological character displacement? Does displacement decrease competition?

    Science.gov (United States)

    Abrams, Peter A; Cortez, Michael H

    2015-12-01

    Interspecific competition for resources is generally considered to be the selective force driving ecological character displacement, and displacement is assumed to reduce competition. Skeptics of the prevalence of character displacement often cite lack of evidence of competition. The present article uses a simple model to examine whether competition is needed for character displacement and whether displacement reduces competition. It treats systems with competing resources, and considers cases when only one consumer evolves. It quantifies competition using several different measures. The analysis shows that selection for divergence of consumers occurs regardless of the level of between-resource competition or whether the indirect interaction between the consumers is competition (-,-), mutualism (+,+), or contramensalism (+,-). Also, divergent evolution always decreases the equilibrium population size of the evolving consumer. Whether divergence of one consumer reduces or increases the impact of a subsequent perturbation of the other consumer depends on the parameters and the method chosen for measuring competition. Divergence in mutualistic interactions may reduce beneficial effects of subsequent increases in the other consumer's population. The evolutionary response is driven by an increase in the relative abundance of the resource the consumer catches more rapidly. Such an increase can occur under several types of interaction. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

  8. Nanomechanical displacement sensing using a quantum point contact

    International Nuclear Information System (INIS)

    Cleland, A.N.; Aldridge, J.S.; Driscoll, D.C.; Gossard, A. C.

    2002-01-01

    We describe a radio frequency mechanical resonator that includes a quantum point contact, defined using electrostatic top gates. We can mechanically actuate the resonator using either electrostatic or magnetomotive forces. We demonstrate the use of the quantum point contact as a displacement sensor, operating as a radio frequency mixer at the mechanical resonance frequency of 1.5 MHz. We calculate a displacement sensitivity of about 3x10 -12 m/Hz 1/2 . This device will potentially permit quantum-limited displacement sensing of nanometer-scale resonators, allowing the quantum entanglement of the electronic and mechanical degrees of freedom of a nanoscale system

  9. Laser microspeckle technique in displacement measurement near a crack tip

    Science.gov (United States)

    Tang, Z. Q.; Wu, K. C.; Cheng, C. H.; Chern, S. S.; Hsiao, C. C.

    1983-01-01

    The laser speckle method has been found quite useful in obtaining in-plane displacement measurements. It is especially useful if the displacement field in a small region can be effectively determined. By obtaining directly the speckle patterns at higher magnifications, a better distinction of the displacements in the vicinity of a crack tip is possible. In this short report some results are obtained and compared with those calculated from linear fracture mechanics and the finite element method for an aluminum crack.

  10. Myeloid cells expressing VEGF and arginase-1 following uptake of damaged retinal pigment epithelium suggests potential mechanism that drives the onset of choroidal angiogenesis in mice.

    Directory of Open Access Journals (Sweden)

    Jian Liu

    Full Text Available Whilst data recognise both myeloid cell accumulation during choroidal neovascularisation (CNV as well as complement activation, none of the data has presented a clear explanation for the angiogenic drive that promotes pathological angiogenesis. One possibility that is a pre-eminent drive is a specific and early conditioning and activation of the myeloid cell infiltrate. Using a laser-induced CNV murine model, we have identified that disruption of retinal pigment epithelium (RPE and Bruch's membrane resulted in an early recruitment of macrophages derived from monocytes and microglia, prior to angiogenesis and contemporaneous with lesional complement activation. Early recruited CD11b(+ cells expressed a definitive gene signature of selective inflammatory mediators particularly a pronounced Arg-1 expression. Accumulating macrophages from retina and peripheral blood were activated at the site of injury, displaying enhanced VEGF expression, and notably prior to exaggerated VEGF expression from RPE, or earliest stages of angiogenesis. All of these initial events, including distinct VEGF (+ Arg-1(+ myeloid cells, subsided when CNV was established and at the time RPE-VEGF expression was maximal. Depletion of inflammatory CCR2-positive monocytes confirmed origin of infiltrating monocyte Arg-1 expression, as following depletion Arg-1 signal was lost and CNV suppressed. Furthermore, our in vitro data supported a myeloid cell uptake of damaged RPE or its derivatives as a mechanism generating VEGF (+ Arg-1(+ phenotype in vivo. Our results reveal a potential early driver initiating angiogenesis via myeloid-derived VEGF drive following uptake of damaged RPE and deliver an explanation of why CNV develops during any of the stages of macular degeneration and can be explored further for therapeutic gain.

  11. Pore-Scale Imaging and Analysis of Phase Topologies and Displacement Mechanisms for CO2-Brine Two-Phase Flow in Unconsolidated Sand Packs

    Science.gov (United States)

    Lv, Pengfei; Song, Yongchen; Liu, Yu; Wang, Bin; Jiang, Lanlan; Wu, Bohao; Liu, Shuyang; Chen, Junlin

    2017-11-01

    CO2 storage in saline aquifers is considered a potential solution for CO2 mitigation, owing to its significant capacity and worldwide distribution capability. It is therefore becoming more important to understand the underground CO2/brine flow mechanisms. CO2 migration is primarily controlled by the pore-scale subsurface flows in different saline aquifer sites with variable reservoir formation compositions and reservoir conditions. Variations occur in the state of CO2 phase (gas versus supercritical), brine salinity, and rock wettability, under different reservoir conditions, and may result in different subsurface CO2/brine migration phenomena. In this study, we investigate the drainage and imbibition procedures of CO2 and brine by injecting fluids into unconsolidated sand packs under different conditions of CO2 phase states, brine salinity, and wettability of sand packs. The pore-scale fluid distribution is visualized using micro X-ray computed tomography (micro-CT). It is found that the phase states of CO2, brine salinity, and wettability have low impacts on CO2 distribution during drainage. However, the increase in brine salinity significantly damages the connectedness of the water phase in pore structures and further decreases the CO2-brine interfacial areas. In addition, a pore-scale event called the droplet fragmentation of nonwetting phase is found to occur in the imbibition procedure, which is considered to be beneficial to the dissolution trapping in CO2 geological storages. It is experimentally demonstrated that the pore structure of rock cores is a factor that significantly contributes to droplet fragmentation.

  12. Control rod displacement

    International Nuclear Information System (INIS)

    Nakazato, S.

    1987-01-01

    This patent describes a nuclear reactor including a core, cylindrical control rods, a single support means supporting the control rods from their upper ends in spaced apart positions and movable for displacing the control rods in their longitudinal direction between a first end position in which the control rods are fully inserted into the core and a second end position in which the control rods are retracted from the core, and guide means contacting discrete regions of the outer surface of each control rod at least when the control rods are in the vicinity of the second end position. The control rods are supported by the support means for longitudinal movement without rotation into and out of the core relative to the guide means to thereby cause the outer surface of the control rods to experience wear as a result of sliding contact with the guide means. The support means are so arranged with respect to the core and the guide means that it is incapable of rotation relative to the guide means. The improvement comprises displacement means being operatively coupled to a respective one of the control rods for periodically rotating the control rod in a single angular direction through an angle selected to change the locations on the outer surfaces of the control rods at which the control rods are contacted by the guide means during subsequent longitudinal movement of the control rods

  13. Study of the dynamics of the lower hybrid wave during current drive in tokamaks and of the Weyl-Wigner in quantum mechanics

    International Nuclear Information System (INIS)

    Bizarro, J.P.

    1993-10-01

    A comprehensive and detailed investigation is presented on the dynamics of the lower hybrid wave during current drive in tokamaks in situations where toroidally induced ray stochasticity is important and on the Weyl-Wigner formalism for rotation angle and angular momentum variables in quantum mechanics. It is shown that ray-tracing and Fokker-Planck codes are reliable tools for modelling the physics of lower-hybrid current drive provided a large number of rays is used when stochastic effects are important, and, in particular, that such codes are capable of reproducing the experimentally observed features of the hard X-ray emission. The balance between the wave damping and the stochastic divergence of nearby ray trajectories appears to be of great importance in governing the dynamics of the launched power spectrum and in establishing the characteristics of the deposition patterns. The implications of rotational periodicity and of angular momentum quantization for the Weyl-Wigner formalism are analyzed. Particular attention is paid to discreteness and its consequences: importance of evenness and oddness, use of two difference operators instead of one differential operator. 24 refs

  14. Identification of the mechanisms that drive the toxicity of TiO2 particulates: the contribution of physicochemical characteristics

    Directory of Open Access Journals (Sweden)

    Peters Sheona

    2009-12-01

    Full Text Available Abstract This review focuses on outlining the toxicity of titanium dioxide (TiO2 particulates in vitro and in vivo, in order to understand their ability to detrimentally impact on human health. Evaluating the hazards associated with TiO2 particles is vital as it enables risk assessments to be conducted, by combining this information with knowledge on the likely exposure levels of humans. This review has concentrated on the toxicity of TiO2, due to the fact that the greatest number of studies by far have evaluated the toxicity of TiO2, in comparison to other metal oxide particulates. This derives from historical reasons (whereby the size dependency of particulate toxicity was first realised for TiO2 and due to its widespread application within consumer products (such as sunscreens. The pulmonary and dermal hazards of TiO2 have been a particular focus of the available studies, due to the past use of TiO2 as a (negative control when assessing the pulmonary toxicity of particulates, and due to its incorporation within consumer products such as sunscreens. Mechanistic processes that are critical to TiO2 particulate toxicity will also be discussed and it is apparent that, in the main, the oxidant driven inflammatory, genotoxic and cytotoxic consequences associated with TiO2 exposure, are inherently linked, and are evident both in vivo and in vitro. The attributes of TiO2 that have been identified as being most likely to drive the observed toxicity include particle size (and therefore surface area, crystallinity (and photocatalytic activity, surface chemistry, and particle aggregation/agglomeration tendency. The experimental set up also influences toxicological outcomes, so that the species (or model used, route of exposure, experiment duration, particle concentration and light conditions are all able to influence the findings of investigations. In addition, the applicability of the observed findings for particular TiO2 forms, to TiO2 particulates in

  15. Drowsy Driving

    Science.gov (United States)

    ... at least 8 hours. 8-9 Develop good sleeping habits such as sticking to a sleep schedule. If ... K, Howard ME. Cognitive components of simulated driving performance: sleep loss effects and predictors. Accid Anal Prev. 2012; ...

  16. Distracted Driving

    Science.gov (United States)

    ... Communities Toolkit Best Practices Guide Publications Motorcycle Safety Bicycle Safety Publications Global Road Safety Get Email Updates ... study. The Insurance Institute for Highway Safety keeps track of distracted driving laws. 7 As of June ...

  17. The Role of Turbulent Pressure as a Coherent Pulsational Driving Mechanism: The Case of the δ Scuti Star HD 187547

    DEFF Research Database (Denmark)

    Antoci, V.; Cunha, M.; Houdek, G.

    2014-01-01

    HD 187547 was the first candidate that led to the suggestion that solar-like oscillations are present in δ Scuti stars. Longer observations, however, show that the modes interpreted as solar-like oscillations have either very long mode lifetimes, longer than 960 days, or are coherent. These results...... are incompatible with the nature of "pure" stochastic excitation as observed in solar-like stars. Nonetheless, one point is certain: the opacity mechanism alone cannot explain the oscillation spectrum of HD 187547. Here we present new theoretical investigations showing that convection dynamics can intrinsically...... excite coherent pulsations in the chemically peculiar δ Scuti star HD 187547. More precisely, it is the perturbations of the mean Reynold stresses (turbulent pressure) that drives the pulsations and the excitation takes place predominantly in the hydrogen ionization zone....

  18. Displacement operators: the classical face of their quantum phase

    Science.gov (United States)

    Vutha, Amar C.; Bohr, Eliot A.; Ransford, Anthony; Campbell, Wesley C.; Hamilton, Paul

    2018-03-01

    In quantum mechanics, the operator representing the displacement of a system in position or momentum is always accompanied by a path-dependent phase factor. In particular, two non-parallel displacements in phase space do not compose together in a simple way, and the order of these displacements leads to different displacement composition phase factors. These phase factors are often attributed to the nonzero commutator between quantum position and momentum operators, but such a mathematical explanation might be unsatisfactory to students who are after more physical insight. We present a couple of simple demonstrations, using classical wave mechanics and classical particle mechanics, that provide some physical intuition for the phase associated with displacement operators.

  19. Interspecies Chemical Signals Released into the Environment May Create Xenohormetic, Hormetic and Cytostatic Selective Forces that Drive the Ecosystemic Evolution of Longevity Regulation Mechanisms.

    Science.gov (United States)

    Burstein, Michelle T; Beach, Adam; Richard, Vincent R; Koupaki, Olivia; Gomez-Perez, Alejandra; Goldberg, Alexander A; Kyryakov, Pavlo; Bourque, Simon D; Glebov, Anastasia; Titorenko, Vladimir I

    2012-01-01

    Various organisms (i.e., bacteria, fungi, plants and animals) within an ecosystem can synthesize and release into the environment certain longevity-extending small molecules. Here we hypothesize that these interspecies chemical signals can create xenohormetic, hormetic and cytostatic selective forces driving the ecosystemic evolution of longevity regulation mechanisms. In our hypothesis, following their release into the environment by one species of the organisms composing an ecosystem, such small molecules can activate anti-aging processes and/or inhibit pro-aging processes in other species within the ecosystem. The organisms that possess the most effective (as compared to their counterparts of the same species) mechanisms for sensing the chemical signals produced and released by other species and for responding to such signals by undergoing certain hormetic and/or cytostatic life-extending changes to their metabolism and physiology are expected to live longer then their counterparts within the ecosystem. Thus, the ability of a species of the organisms composing an ecosystem to undergo life-extending metabolic or physiological changes in response to hormetic or cytostatic chemical compounds released to the ecosystem by other species: 1) increases its chances of survival; 2) creates selective forces aimed at maintaining such ability; and 3) enables the evolution of longevity regulation mechanisms.

  20. Displacing the Patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    as an affective care recipient, as a citizen with rights and as an individual need-oriented user on the one hand. On the other hand, the goal of patient satisfaction also deploys market perceptions of patients as homogeneous target groups to which information can be standardised. In the latter (market orientation......The analysis is based on an empirical study of a hospital’s communication strategy entitled: 'The Perspective of the Patient'. The paper asks how the strategy organizes communication work as situated displacements of the patient. Based on methodological elements from situational analysis (Clarke......), the patient is also a resource for organizational development and a customer with consumer behavior. Overall, the strategy presents an information-pursuing patient figure making it possible to streamline the organization's care orientation on market conditions. In contrast to Annemarie Mol’s dichotomy of care...

  1. Displacing the patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    a care-oriented approach to the patient and also deploys market perceptions of patients as homogeneous target groups to which information can be standardized. In the latter approach (market orientation), the patient is also a resource for organizational development. Overall, the strategy presents......This analysis is based on an empirical study of a Danish hospital‟s communication programme entitled: 'The Perspective of the Patient'. The paper explores how strategic documents of the programme organize the communication work through situated displacements of the patient. Based on methodological...... an information-pursuing patient figure making it possible to streamline the organization's care orientation on market conditions. In contrast to a dichotomy of care and market as mutually exclusive (Mol 2008), care and market appear to be intertwined in political patient figures through which the organization...

  2. Displacing the Patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    as an affective care recipient, as a citizen with rights and as an individual need-oriented user on the one hand. On the other hand, the goal of patient satisfaction also deploys market perceptions of patients as homogeneous target groups to which information can be standardised. In the latter (market orientation......), the patient is also a resource for organizational development and a customer with consumer behavior. Overall, the strategy presents an information-pursuing patient figure making it possible to streamline the organization's care orientation on market conditions. In contrast to Annemarie Mol’s dichotomy of care......The analysis is based on an empirical study of a hospital’s communication strategy entitled: 'The Perspective of the Patient'. The paper asks how the strategy organizes communication work as situated displacements of the patient. Based on methodological elements from situational analysis (Clarke...

  3. Feature displacement interpolation

    DEFF Research Database (Denmark)

    Nielsen, Mads; Andresen, Per Rønsholt

    1998-01-01

    Given a sparse set of feature matches, we want to compute an interpolated dense displacement map. The application may be stereo disparity computation, flow computation, or non-rigid medical registration. Also estimation of missing image data, may be phrased in this framework. Since the features...... often are very sparse, the interpolation model becomes crucial. We show that a maximum likelihood estimation based on the covariance properties (Kriging) show properties more expedient than methods such as Gaussian interpolation or Tikhonov regularizations, also including scale......-selection. The computational complexities are identical. We apply the maximum likelihood interpolation to growth analysis of the mandibular bone. Here, the features used are the crest-lines of the object surface....

  4. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    OpenAIRE

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic el...

  5. Passive temperature compensation in hydraulic dashpot used for the shut-off rod drive mechanism of a nuclear reactor

    International Nuclear Information System (INIS)

    Singh, Narendra K.; Badodkar, Deepak N.

    2015-01-01

    Highlights: • Passive temperature compensation in hydraulic dashpot has been studied numerically as well as experimentally. • Temperature compensation is achieved by reducing the clearances in the hydraulic dashpot at elevated temperature to compensate for the viscosity reduction. • Temperature compensation effects due to difference in thermal expansion of common engineering materials and use of bimetallic strips have been analyzed. • Design of a novel passive temperature compensating hydraulic dashpot is presented, which can be used for wide range of temperature variations. - Abstract: Passive temperature compensating hydraulic dashpot has been studied numerically as well as experimentally in this paper. Study is focused on reducing the clearances of the hydraulic dashpot at elevated temperature which intern compensates for the reduction in viscosity of damping oil and the dashpot gives uniform performance for wide range of temperature variation. Temperature compensation effects are mainly due to difference in the thermal expansion of materials. Different combinations of materials are used to reduce the dashpot clearances at elevated temperature. Finite element commercial code COMSOL Multiphysics 5.1 has been used for numerical analysis. Fluid-structure analysis has been carried-out to study the thermal expansion and pressure generated in the hydraulic dashpot. Multiphysics study with solid mechanics, laminar flow and moving mesh interfaces has been carried-out. Thermal expansion results of study-1 (solid mechanics) are further extended in to study-2 (laminar flow and moving mesh) and dashpot pressure is estimated. These results show that bimetallic strip improves the dashpot performance at 55 °C but do not fully compensate beyond that and less severe impacts occurs. Specific combinations of design and materials have been presented in this paper for obtaining maximum temperature compensation. A novel passive temperature compensating hydraulic dashpot

  6. Linear micromechanical stepping drive for pinhole array positioning

    International Nuclear Information System (INIS)

    Endrödy, Csaba; Mehner, Hannes; Hoffmann, Martin; Grewe, Adrian

    2015-01-01

    A compact linear micromechanical stepping drive for positioning a 7 × 5.5 mm 2 optical pinhole array is presented. The system features a step size of 13.2 µm and a full displacement range of 200 µm. The electrostatic inch-worm stepping mechanism shows a compact design capable of positioning a payload 50% of its own weight. The stepping drive movement, step sizes and position accuracy are characterized. The actuated pinhole array is integrated in a confocal chromatic hyperspectral imaging system, where coverage of the object plane, and therefore the useful picture data, can be multiplied by 14 in contrast to a non-actuated array. (paper)

  7. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    Science.gov (United States)

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-05-22

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

  8. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Nanying Shentu

    2014-05-01

    Full Text Available Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA. Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

  9. Retinol and ascorbate drive erasure of epigenetic memory and enhance reprogramming to naïve pluripotency by complementary mechanisms.

    Science.gov (United States)

    Hore, Timothy Alexander; von Meyenn, Ferdinand; Ravichandran, Mirunalini; Bachman, Martin; Ficz, Gabriella; Oxley, David; Santos, Fátima; Balasubramanian, Shankar; Jurkowski, Tomasz P; Reik, Wolf

    2016-10-25

    Epigenetic memory, in particular DNA methylation, is established during development in differentiating cells and must be erased to create naïve (induced) pluripotent stem cells. The ten-eleven translocation (TET) enzymes can catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and further oxidized derivatives, thereby actively removing this memory. Nevertheless, the mechanism by which the TET enzymes are regulated, and the extent to which they can be manipulated, are poorly understood. Here we report that retinoic acid (RA) or retinol (vitamin A) and ascorbate (vitamin C) act as modulators of TET levels and activity. RA or retinol enhances 5hmC production in naïve embryonic stem cells by activation of TET2 and TET3 transcription, whereas ascorbate potentiates TET activity and 5hmC production through enhanced Fe 2+ recycling, and not as a cofactor as reported previously. We find that both ascorbate and RA or retinol promote the derivation of induced pluripotent stem cells synergistically and enhance the erasure of epigenetic memory. This mechanistic insight has significance for the development of cell treatments for regenenerative medicine, and enhances our understanding of how intrinsic and extrinsic signals shape the epigenome.

  10. Kinematics of the 2015 San Ramon, California earthquake swarm: Implications for fault zone structure and driving mechanisms

    Science.gov (United States)

    Xue, Lian; Bürgmann, Roland; Shelly, David R.; Johnson, Christopher W.; Taira, Taka'aki

    2018-05-01

    Earthquake swarms represent a sudden increase in seismicity that may indicate a heterogeneous fault-zone, the involvement of crustal fluids and/or slow fault slip. Swarms sometimes precede major earthquake ruptures. An earthquake swarm occurred in October 2015 near San Ramon, California in an extensional right step-over region between the northern Calaveras Fault and the Concord-Mt. Diablo fault zone, which has hosted ten major swarms since 1970. The 2015 San Ramon swarm is examined here from 11 October through 18 November using template matching analysis. The relocated seismicity catalog contains ∼4000 events with magnitudes between - 0.2 swarm illuminated three sub-parallel, southwest striking and northwest dipping fault segments of km-scale dimension and thickness of up to 200 m. The segments contain coexisting populations of different focal-mechanisms, suggesting a complex fault zone structure with several sets of en échelon fault orientations. The migration of events along the three planar structures indicates a complex fluid and faulting interaction processes. We searched for correlations between seismic activity and tidal stresses and found some suggestive features, but nothing that we can be confident is statistically significant.

  11. Flow pathways and nutrient transport mechanisms drive hydrochemical sensitivity to climate change across catchments with different geology and topography

    Science.gov (United States)

    Crossman, J.; Futter, M. N.; Whitehead, P. G.; Stainsby, E.; Baulch, H. M.; Jin, L.; Oni, S. K.; Wilby, R. L.; Dillon, P. J.

    2014-12-01

    Hydrological processes determine the transport of nutrients and passage of diffuse pollution. Consequently, catchments are likely to exhibit individual hydrochemical responses (sensitivities) to climate change, which are expected to alter the timing and amount of runoff, and to impact in-stream water quality. In developing robust catchment management strategies and quantifying plausible future hydrochemical conditions it is therefore equally important to consider the potential for spatial variability in, and causal factors of, catchment sensitivity, as it is to explore future changes in climatic pressures. This study seeks to identify those factors which influence hydrochemical sensitivity to climate change. A perturbed physics ensemble (PPE), derived from a series of global climate model (GCM) variants with specific climate sensitivities was used to project future climate change and uncertainty. Using the INtegrated CAtchment model of Phosphorus dynamics (INCA-P), we quantified potential hydrochemical responses in four neighbouring catchments (with similar land use but varying topographic and geological characteristics) in southern Ontario, Canada. Responses were assessed by comparing a 30 year baseline (1968-1997) to two future periods: 2020-2049 and 2060-2089. Although projected climate change and uncertainties were similar across these catchments, hydrochemical responses (sensitivities) were highly varied. Sensitivity was governed by quaternary geology (influencing flow pathways) and nutrient transport mechanisms. Clay-rich catchments were most sensitive, with total phosphorus (TP) being rapidly transported to rivers via overland flow. In these catchments large annual reductions in TP loads were projected. Sensitivity in the other two catchments, dominated by sandy loams, was lower due to a larger proportion of soil matrix flow, longer soil water residence times and seasonal variability in soil-P saturation. Here smaller changes in TP loads, predominantly

  12. Point Coupled Displacement Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Real-time displacement measurement techniques are needed to acquire aerodynamic and structural system characteristics in flight. This proposal describes the...

  13. MRI of displaced meniscal fragments

    International Nuclear Information System (INIS)

    Dunoski, Brian; Zbojniewicz, Andrew M.; Laor, Tal

    2012-01-01

    A torn meniscus frequently requires surgical fixation or debridement as definitive treatment. Meniscal tears with associated fragment displacement, such as bucket handle and flap tears, can be difficult to recognize and accurately describe on MRI, and displaced fragments can be challenging to identify at surgery. A displaced meniscal fragment can be obscured by synovium or be in a location not usually evaluated at arthroscopy. We present a pictorial essay of meniscal tears with displaced fragments in patients referred to a pediatric hospital in order to increase recognition and accurate interpretation by the radiologist, who in turn can help assist the surgeon in planning appropriate therapy. (orig.)

  14. Driving things

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2015-01-01

    . pp.155 ((http://www.infrastructure.gov.au/roads/safety/publications/2010/pdf/rsgr_2010001.pdf)) Nevile, M., Haddington, P., Heinemann, T., Rauniomaa, M. (Eds.) Interacting with objects: Language, materiality, and social activity. Amsterdam/Philadelphia: John Benjamins. Redshaw, S. (2008....... Interaction with objects reflects the car’s role beyond mere transport as a site of personal, social, and work life (Featherstone et al. 2005; Redshaw 2008). Studies of interaction examine this role as it is actually enacted, understood, and accomplished, in situ through participants’ practices (e.g. Laurier...... of in-car distractions, and how they impact driving activities (Nevile & Haddington 2010). Data are video recordings of ordinary journeys, capturing drivers and passengers in real-world real-time driving situations (27 hours, 90 journeys). For driving and road safety, research and experience has...

  15. Community Drive

    DEFF Research Database (Denmark)

    Magnussen, Rikke

    2018-01-01

    opportunity to break boundaries between research institutions and surrounding communities through the involvement of new types of actors, knowledge forms and institutions (OECD, 2011). This paper presents the project Community Drive a three year cross disciplinary community-driven game– and data-based project....... In the paper we present how the project Community Drive initiated in May 2018 is based on results from pilot projects conducted from 2014 – 2017. Overall these studies showed that it is a strong motivational factor for students to be given the task to change their living conditions through redesign...... of living in the area. The paper discusses potentials and pitfalls of designing community-driven science gaming environments and how results from previous studies can form the project Community Drive....

  16. Back-arc Extension: Critical Analisys of Subduction-related and Non Subduction-related Driving Mechanisms

    Science.gov (United States)

    Mantovani, E.; Viti, M.; Babbucci, D.; Tamburelli, C.; Albarello, D.

    It is argued that the opening of back arc basins can hardly be explained as an effect of subduction related forces, since this kind of interpretation has not yet provided plausible explanations for several major features of such processes in the world. In particular, it is not clear why back arc extension occurs in some subduction zones and not in others, why extension ceased in zones where subduction has remained active, why the arcs associated with back arc basins are often characterized by a strongly curved shape, why arc-trench-back arc systems do not develop along the entire length of consuming borders and why no significant correlation can be recognized between any parameter of subduction processes and the occurrence of back arc extension. In addition, modelling experiments indicate that the magnitude of the tensional stress induced in the overriding plate by subduction-related forces is significantly lower than the lithospheric strength. These problems are discussed, in particular, for three subduction-related interpretations, the "slab-pull", the "corner flow" and the "sea an- chor" models, which seem to be the most quoted in literature. It is then argued that possible solutions of the above problems may be provided by the extrusion model, which postulates that back arc basins are generated by the forced separation of the arc from the overriding plate, along a sector of the consuming border. This separa- tion is generally caused by the oblique indentation of strong and buoyant structures against the accretionary belt. In this view, subduction and back arc extension are not causally linked one to the other, but rather represent simultaneous effects of the lateral migration of the arc, driven by plate convergence. It is pointed out that the conditions required for the occurrence of this kind of mechanism may be recognized in the tec- tonic contexts where back arc basins developed in the wake of arc-trench migrating systems. On the other hand, in the zones

  17. Near-term hybrid vehicle program, phase 1. Appendix B: Design trade-off studies. [various hybrid/electric power train configurations and electrical and mechanical drive-line components

    Science.gov (United States)

    1979-01-01

    The relative attractiveness of various hybrid/electric power train configurations and electrical and mechanical drive-line components was studied. The initial screening was concerned primarily with total vehicle weight and economic factors and identified the hybrid power train combinations which warranted detailed evaluation over various driving cycles. This was done using a second-by-second vehicle simulation program which permitted the calculations of fuel economy, electricity usage, and emissions as a function of distance traveled in urban and highway driving. Power train arrangement possibilities were examined in terms of their effect on vehicle handling, safety, serviceability, and passenger comfort. A dc electric drive system utilizing a separately excited motor with field control and battery switching was selected for the near term hybrid vehicle. Hybrid vehicle simulations showed that for the first 30 mi (the electric range of the vehicle) in urban driving, the fuel economy was 80 mpg using a gasoline engine and 100 mpg using a diesel engine. In urban driving the hybrid would save about 75% of the fuel used by the conventional vehicle and in combined urban/highway driving the fuel saving is about 50%.

  18. Self-driving carsickness.

    Science.gov (United States)

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  19. An APC:WNT counter-current-like mechanism regulates cell division along the colonic crypt axis: a mechanism that explains how APC mutations induce proliferative abnormalities that drive colon cancer development.

    Directory of Open Access Journals (Sweden)

    Bruce M Boman

    2013-11-01

    Full Text Available APC normally down-regulates WNT signaling in human colon, and APC mutations cause proliferative abnormalities in premalignant crypts leading to colon cancer, but the mechanisms are unclear at the level of spatial and functional organization of the crypt. Accordingly, we postulated a counter-current-like mechanism based on gradients of factors (APC;WNT that regulate colonocyte proliferation along the crypt axis. During crypt renewal, stem cells (SCs at the crypt bottom generate non-SC daughter cells that proliferate and differentiate while migrating upwards. The APC concentration is low at the crypt bottom and high at the top (where differentiated cells reside. WNT signaling, in contrast, is high at the bottom (where SCs reside and low at the top. Given that WNT and APC gradients are counter to one another, we hypothesized that a counter-current-like mechanism exists. Since both APC and WNT signaling components (e.g. survivin are required for mitosis, this mechanism establishes a zone in the lower crypt where conditions are optimal for maximal cell division and mitosis orientation (symmetric versus asymmetric. APC haploinsufficiency diminishes the APC gradient, shifts the proliferative zone upwards, and increases symmetric division, which causes SC overpopulation. In homozygote mutant crypts, these changes are exacerbated. Thus, APC-mutation-induced changes in the counter-current-like mechanism cause expansion of proliferative populations (SCs, rapidly-proliferating cells during tumorigenesis. We propose this mechanism also drives crypt fission, functions in the crypt cycle, and underlies adenoma development. Novel chemoprevention approaches designed to normalize the two gradients and readjust the proliferative zone downwards, might thwart progression of these premalignant changes.

  20. A computationally efficient model to capture the inertia of the piezoelectric stack in impact drive mechanism in the case of the in-pipe inspection application

    Directory of Open Access Journals (Sweden)

    J. Li

    2016-03-01

    Full Text Available This paper presents a new model for the piezoelectric actuator (PA in the context of in the impact drive mechanism (IDM for the in-pipe inspection application. The feature of the model is capturing the inertia of PA stack in a distributed manner as opposed to the lumped manner in literature. The benefit arising from this feature is a balanced trade-off between computational efficiency and model accuracy. The study presented in this paper included both theoretical development (i.e. the model of the piezoelectric actuator and the model of the entire IDM which includes the actuator and experimental verification of the model. The study has shown that (1 the inertia of the PA in such a robot will significantly affect the accuracy of the entire model of IDM and (2 the simulation of the dynamic behavior with the proposed model is sufficiently accurate by comparing with the experiment. It is thus recommended that the inertia of the PA be considered in the entire model of the IDM robot. The model is an analytical type, which has a high potential to be used for the model-based control of the IDM robot and optimization of its design for a much improved performance of the IDM system.

  1. Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Susan L.; Cinson, Anthony D.; MacFarlan, Paul J.; Hanson, Brady D.; Mathews, Royce

    2012-08-01

    The objective of this investigation was to evaluate the efficacy of ultrasonic testing (UT) for primary water leak path assessments of reactor pressure vessel (RPV) upper head penetrations. Operating reactors have experienced leakage when stress corrosion cracking of nickel-based alloy penetrations allowed primary water into the annulus of the interference fit between the penetration and the low-alloy steel RPV head. In this investigation, UT leak path data were acquired for an Alloy 600 control rod drive mechanism nozzle penetration, referred to as Nozzle 63, which was removed from the North Anna Unit 2 reactor when the RPV head was replaced in 2002. In-service inspection prior to the head replacement indicated that Nozzle 63 had a probable leakage path through the interference fit region. Nozzle 63 was examined using a phased-array UT probe with a 5.0-MHz, eight-element annular array. Immersion data were acquired from the nozzle inner diameter surface. The UT data were interpreted by comparing to responses measured on a mockup penetration with known features. Following acquisition of the UT data, Nozzle 63 was destructively examined to determine if the features identified in the UT examination, including leakage paths and crystalline boric acid deposits, could be visually confirmed. Additional measurements of boric acid deposit thickness and low-alloy steel wastage were made to assess how these factors affect the UT response. The implications of these findings for interpreting UT leak path data are described.

  2. On the continuous functioning of an internal mechanism that drives the Eastern Mediterranean thermohaline circulation: The recent activation of the Aegean Sea as a dense water source area

    Science.gov (United States)

    Krokos, George; Velaoras, Dimitris; Korres, Gerasimos; Perivoliotis, Leonidas; Theocharis, Alexander

    2014-01-01

    The scientific interest in Eastern Mediterranean (EMed) processes of major importance has been revived in recent years due to the predominance of internal variability manifested in a decadal time scale leading to the alternating activation of the two dense water sources (i.e. the Adriatic and Aegean Seas). Analysis of available hydrographic data during the 2003-2012 period reveals an anticorrelated almost decadal oscillation in the thermohaline properties of the upper and intermediate water masses in both the Ionian and the Levantine/Aegean Seas. This event is the manifestation of an ongoing internal mechanism initially introduced by Theocharis et al. (in press) which periodically disturbs the upper thermohaline EMed conveyor belt and changes the respective water mass pathways, thus driving the alternating activation of the two dense water sources through salinity preconditioning. Since 2004-2005, the salinity of the upper/intermediate layer in the eastern part of the EMed gradually increased up to 2010, while at the same time it decreased in the North Ionian Sea. During the same period we observed the activation of the Aegean Sea as a Dense Water Formation area even though the atmospheric forcing conditions were not favorable. After 2010 the salinity trend reversed in both regions. This suggests that in the near future the salinity preconditioning of the Adriatic Sea will be favored again following the respective water mass pathway changes.

  3. The Displaced ‘Dispositif’

    Directory of Open Access Journals (Sweden)

    Guy Edmonds

    2017-11-01

    Full Text Available “Dispositif” is a term used in film studies since the 1970s to describe the entire system of mechanical and human factors which together bring about the cinema experience. It therefore refers to (amongst other things the space of the auditorium, the screen, the projection technology and the physiology of the spectator. Many of its qualifying components are masked from the view of participants in the system. The dispositif’s purpose is to set up the conditions for a specific type of cognitive experience, one which mirrors and extends (and in some readings, controls the experience of its participants. The Displaced Dispositif is a performance designed for the space of a cinema theatre, but featuring the projection of fragments of early silent cinema on a coeval (1910s film projector from the auditorium. The film fragments are live-scored by the sound artist, Shaun Lewin, using a combination of closely mic’d sources on the projector itself, luminance data from the projected image and EEG brainwave data recorded from participants during previous projections of the film. Displacing elements in the dispositif in this way, by shifting modalities, situating in parallel, feeding back and layering, draws attention to its hidden existence and creates the potential for a more knowing and informed participation in the cinema experience. It also serves to demonstrate the degree to which dispositifs of modern cinema spectatorship, which have morphed and proliferated since the widespread digitization of film heritage, have radically altered both the technological and experiential qualities of the medium. By integrating EEG data, the performance adds the dimension of electrophysiological experience to the long tradition within experimental cinema of artists calling attention to Cinema’s hidden structures. As well as challenging the dominance of the worldview propagated by the film industry, the performance also signals a means of re-engaging with the

  4. Performance comparison of a novel configuration of beta-type Stirling engines with rhombic drive engine

    International Nuclear Information System (INIS)

    Solmaz, Hamit; Karabulut, Halit

    2014-01-01

    Highlights: • The paper describes a novel arrangement of a beta-type Stirling engine. • Its performance was compared with rhombic drive engine. • The power output of the engine was found to be greater than rhombic drive. • Efficiency was found to be higher than rhombic drive at the same working fluid mass. • Efficiency was found to be lower than rhombic drive at the same charge pressure. - Abstract: This study presents a beta type Stirling engine mechanism and its performance analysis. The displacer motion of the engine is performed by a lever mechanism. The performance of the engine was investigated via comparing with a rhombic-drive engine possessing an equal sided rhombic. Comparison was made for kinematic behaviors, power and thermal efficiency. For comparison; the piston swept volume, the inner heat transfer area, the hot and cold end temperatures, the inner heat transfer coefficient, charge pressure and dead volumes were kept equal for both engines. As working fluid the helium was used. Thermodynamic treatments of engines were performed via the nodal analysis. The power of the lever driven engine was found to be greater than the power of the rhombic drive engine. Under the equal charge pressure, the thermal efficiency of the lever driven engine was found to be lower than the efficiency of the rhombic drive engine however, under the equal working fluid mass the thermal efficiency of the lever driven engine was found to be greater than that of the rhombic drive engine. The external volume and mass of the lever driven engine is lower than the rhombic drive engine

  5. Control rod drives

    International Nuclear Information System (INIS)

    Oonuki, Koji.

    1981-01-01

    Purpose: To increase the driving speed of control rods at rapid insertion with an elongate control rod and an extension pipe while ensuring sufficient buffering performance in a short buffering distance, by providing a plurality of buffers to an extension pipe between a control rod drive source and a control rod in LMFBR type reactor. Constitution: First, second and third buffers are respectively provided to an acceleration piston, an extension pipe and a control rod respectively and the insertion positions for each of the buffers are displaced orderly from above to below. Upon disconnection of energizing current for an electromagnet, the acceleration piston, the extension pipe and the control rod are rapidly inserted in one body. The first, second and third buffers are respectively actuated at each of their falling strokes upon rapid insertion respectively, and the acceleration piston, the extension pipe and the control rod receive the deceleration effect in the order correspondingly. Although the compression force is applied to the control rod only near the stroke end, it does not cause deformation. (Kawakami, Y.)

  6. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    rity, 2NN and 3NN contract towards the impurity, 4NN displacement is anisotropic and beyond this the displacements are oscillatory in nature. However, the number of atoms which displace towards the impurity are more than those which displace away from the impurity. The characteristics of displacements due to Mn impu-.

  7. The chain effects of property-led redevelopment in Shenzhen : Price-shadowing and indirect displacement

    NARCIS (Netherlands)

    Liu, Ying; Tang, Shuangshuang; Geertman, Stan; Lin, Yanliu; van Oort, Frank

    2017-01-01

    Many Chinese cities are undergoing large-scale property-led redevelopment, which can result in both direct and indirect residential displacement. Although a number of studies on direct displacement have been carried out, insights into the mechanisms underlying indirect displacement are lacking. The

  8. Improving Broadband Displacement Detection with Quantum Correlations

    Science.gov (United States)

    Kampel, N. S.; Peterson, R. W.; Fischer, R.; Yu, P.-L.; Cicak, K.; Simmonds, R. W.; Lehnert, K. W.; Regal, C. A.

    2017-04-01

    Interferometers enable ultrasensitive measurement in a wide array of applications from gravitational wave searches to force microscopes. The role of quantum mechanics in the metrological limits of interferometers has a rich history, and a large number of techniques to surpass conventional limits have been proposed. In a typical measurement configuration, the trade-off between the probe's shot noise (imprecision) and its quantum backaction results in what is known as the standard quantum limit (SQL). In this work, we investigate how quantum correlations accessed by modifying the readout of the interferometer can access physics beyond the SQL and improve displacement sensitivity. Specifically, we use an optical cavity to probe the motion of a silicon nitride membrane off mechanical resonance, as one would do in a broadband displacement or force measurement, and observe sensitivity better than the SQL dictates for our quantum efficiency. Our measurement illustrates the core idea behind a technique known as variational readout, in which the optical readout quadrature is changed as a function of frequency to improve broadband displacement detection. And, more generally, our result is a salient example of how correlations can aid sensing in the presence of backaction.

  9. Internal displacement in eastern Burma

    Directory of Open Access Journals (Sweden)

    Heather Rae

    2007-07-01

    Full Text Available The history of post-independent Burma is characterisedby numerous conflicts in this extraordinarily heterogeneous country. Since military rule began in 196 2 Burmahas witnessed gross human rights abuses andmassive displacement.

  10. Displacement sensing system and method

    Science.gov (United States)

    VunKannon, Jr., Robert S

    2006-08-08

    A displacement sensing system and method addresses demanding requirements for high precision sensing of displacement of a shaft, for use typically in a linear electro-dynamic machine, having low failure rates over multi-year unattended operation in hostile environments. Applications include outer space travel by spacecraft having high-temperature, sealed environments without opportunity for servicing over many years of operation. The displacement sensing system uses a three coil sensor configuration, including a reference and sense coils, to provide a pair of ratio-metric signals, which are inputted into a synchronous comparison circuit, which is synchronously processed for a resultant displacement determination. The pair of ratio-metric signals are similarly affected by environmental conditions so that the comparison circuit is able to subtract or nullify environmental conditions that would otherwise cause changes in accuracy to occur.

  11. Transient digitizer with displacement current samplers

    Science.gov (United States)

    McEwan, Thomas E.

    1996-01-01

    A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board.

  12. Shifted axis angular positioning mechanisms – unconventional use of exact constraint design

    Directory of Open Access Journals (Sweden)

    Szykiedans Ksawery

    2018-01-01

    Full Text Available Paper presents some remarks about designing angular positioners having significant angular displacement and shifted axis of rotation. Those driving mechanism are useful in specific applications where mechanism wraps around other object or there is a need of rotation around virtual axis. Examples of those applications like orthotic robots or gimbals for panoramic motions where developed at Faculty of Mechatronics WUT. Usage of exact constraint method was described including its influence to a kinematic structure of designed mechanism.

  13. Sensing Property Modeling for the Novel Horizontal-vertical Composite Underground Displacement Sensor

    OpenAIRE

    Nanying Shentu; Guohua Qiu; Xiong Li; Renyuan Tong; Qing Li

    2014-01-01

    Due to invisibility and complexity of the underground displacement monitoring, there exit few practical monitoring sensors capable of monitoring the underground horizontal and vertical displacements simultaneously. A novel electromagnetic underground displacement sensor able to monitor both the horizontal and the vertical displacements was proposed in our previous studies and abbreviated as the H-V type sensor. Through comprehensive application of Hall sensing mechanism analysis, 3D magnetic ...

  14. Maternal and fetal mechanisms of B cell regulation during pregnancy: human Chorionic Gonadotropin stimulates B cells to produce IL-10 while alpha-fetoprotein drives them into apoptosis

    Directory of Open Access Journals (Sweden)

    Franziska Fettke

    2016-12-01

    Full Text Available Maternal immune tolerance towards the fetus is an essential requisite for pregnancy. While T cell functions are well documented, little is known about the participation of B cells. We have previously suggested that IL-10 producing B cells are involved in pregnancy tolerance in mice and humans. By employing murine and human systems, we report now that fetal trophoblasts positively regulate the generation of IL-10 producing B cells. We next studied the participation of hormones produced by the placenta as well as the fetal protein alpha-fetoprotein (AFP in B cell modulation. Human Chorionic Gonadotropin (hCG, but not progesterone, estrogen or a combination of both, was able to promote changes in B cell phenotype and boost their IL-10 production, which was abolished after blocking hCG. The hCG-induced B cell phenotype was not associated with augmented galactosylation, sialylation or fucosylation of IgG subclasses in their Fc. In vitro, hCG induced the synthesis of asymmetrically glycosylated antibodies in their Fab region. Interestingly, AFP had dual effects depending on the concentration. At concentrations corresponding to maternal serum levels, it did not modify the phenotype or IL-10 secretion of B cells. At fetal concentrations, however, AFP was able to drive B cells into apoptosis, which may indicate a protective mechanism to avoid maternal B cells to reach the fetus.Our data suggests that the fetus secrete factors that promote a pregnancy-friendly B cell phenotype, unraveling interesting aspects of B cell function and modulation by pregnancy hormones and fetal proteins.

  15. Effect of friction time on mechanical and metallurgical properties of continuous drive friction welded Ti6Al4V/SUS321 joints

    International Nuclear Information System (INIS)

    Li, Peng; Li, Jinglong; Salman, Muhammad; Liang, Li; Xiong, Jiangtao; Zhang, Fusheng

    2014-01-01

    Highlights: • The effect of friction time on the microstructure and joint strength was studied. • The fit of burn-off lengths at different times yields a simple equation. • The longer friction time leads to oversized flash in Ti6Al4V side and overgrown IMCs. • An IMZ with width less than 3 μm is beneficial to make a strong metallurgical bond. • The average strength of 560 MPa is obtained and higher than ever reported results. - Abstract: Dissimilar joint of Ti6Al4V titanium alloy and SUS321 stainless steel was fabricated by continuous drive friction welding. The effect of friction time on the mechanical properties was evaluated by hardness measurement and tensile test, while the interfacial microstructure and fracture morphologies were analyzed by scanning electron microscope, energy dispersive spectroscope and X-ray Diffraction. The results show that the tensile strength increases with friction time under the experimental conditions. And the maximum average strength 560 MPa, which is 90.3% of the SUS321 base metal, is achieved at a friction time of 4 s. For all samples, studied fracture occurred along the joint interface, where intermetallic compounds like FeTi, Fe 2 Ti, Ni 3 (Al, Ti) and Fe 3 Ti 3 O and many other phases were formed among elements from the two base metals. The width of intermetallic compounds zone increases with friction time up to 3 μm, below which it is beneficial to make a strong metallurgical bond. However, the longer friction time leads to oversized flash on the Ti6Al4V side and overgrown intermetallic compounds. Finally the optimized friction time was discussed to be in the range of 2–4 s, under which the sound joint with good reproducibility can be expected

  16. Chemical Shift Imaging (CSI) by precise object displacement

    OpenAIRE

    Leclerc, Sebastien; Trausch, Gregory; Cordier, Benoit; Grandclaude, Denis; Retournard, Alain; Fraissard, Jacques; Canet, Daniel

    2006-01-01

    International audience; A mechanical device (NMR lift) has been built for displacing vertically an object (typically a NMR sample tube) inside the NMR probe with an accuracy of 1 Μm. A series of single pulse experiments are performed for incremented vertical positions of the sample. With a sufficiently spatially selective rf field, one obtains chemical shift information along the displacement direction (one dimensional Chemical Shift Imaging – CSI). Knowing the vertical radio-frequency (rf) f...

  17. Dispersive effects of transverse displacements of SLC Arc magnets

    International Nuclear Information System (INIS)

    Murray, J.J.; Fieguth, T.; Kheifets, S.

    1986-01-01

    The SLC Arc magnets are subject to random displacements and field errors resulting in unpredictable transverse displacement of the central trajectory from that of the design. The chosen method of correcting this perturbed trajectory in the SLC Arcs utilizes mechanical movement of the combined function magnets which compose the Arc transport lines. Here we present the results of a recent investigation substantiating the earlier results which led to the adoption of this method

  18. Noninductive current drive in tokamaks

    International Nuclear Information System (INIS)

    Uckan, N.A.

    1985-01-01

    Various current drive mechanisms may be grouped into four classes: (1) injection of energetic particle beams; (2) launching of rf waves; (3) hybrid schemes, which are combinations of various rf schemes (rf plus beams, rf and/or beam plus ohmic heating, etc.); and (4) other schemes, some of which are specific to reactor plasma conditions requiring the presence of alpha particle or intense synchrotron radiation. Particle injection schemes include current drive by neutral beams and relativistic electron beams. The rf schemes include current drive by the lower hybrid (LH) waves, the electron waves, the waves in the ion cyclotron range of frequencies, etc. Only a few of these approaches, however, have been tested experimentally, with the broadest data base available for LH waves. Included in this report are (1) efficiency criteria for current drive, (2) current drive by neutral beam injection, (3) LH current drive, (4) electron cyclotron current drive, (5) current drive by ion cyclotron waves - minority species heating, and (6) current drive by other schemes (such as hybrids and low frequency waves)

  19. Is Fibular Fracture Displacement Consistent with Tibiotalar Displacement?

    NARCIS (Netherlands)

    van den Bekerom, Michel P. J.; van Dijk, C. Niek

    2010-01-01

    We believed open reduction with internal fixation is required for supination-external rotation ankle fractures located at the level of the distal tibiofibular syndesmosis (Lauge-Hanssen SER II and Weber B) with 2 mm or more fibular fracture displacement. The rationale for surgery for these ankle

  20. On virtual displacement and virtual work in Lagrangian dynamics

    International Nuclear Information System (INIS)

    Ray, Subhankar; Shamanna, J

    2006-01-01

    The confusion and ambiguity encountered by students in understanding virtual displacement and virtual work is discussed in this paper. A definition of virtual displacement is presented that allows one to express them explicitly for holonomic (velocity independent), non-holonomic (velocity dependent), scleronomous (time independent) and rheonomous (time dependent) constraints. It is observed that for holonomic, scleronomous constraints, the virtual displacements are the displacements allowed by the constraints. However, this is not so for a general class of constraints. For simple physical systems, it is shown that the work done by the constraint forces on virtual displacements is zero. This motivates Lagrange's extension of d'Alembert's principle to a system of particles in constrained motion. However, a similar zero work principle does not hold for the allowed displacements. It is also demonstrated that d'Alembert's principle of zero virtual work is necessary for the solvability of a constrained mechanical problem. We identify this special class of constraints, physically realized and solvable, as the ideal constraints. The concept of virtual displacement and the principle of zero virtual work by constraint forces are central to both Lagrange's method of undetermined multipliers and Lagrange's equations in generalized coordinates

  1. Project-induced displacement, secondary stressors, and health.

    Science.gov (United States)

    Cao, Yue; Hwang, Sean-Shong; Xi, Juan

    2012-04-01

    It has been estimated that about 15 million people are displaced by development projects around the world each year. Despite the magnitude of people affected, research on the health and other impacts of project-induced displacement is rare. This study extends existing knowledge by exploring the short-term health impact of a large scale population displacement resulting from China's Three Gorges Dam Project. The study is theoretically guided by the stress process model, but we supplement it with Cernea's impoverishment risks and reconstruction (IRR) model widely used in displacement literature. Our panel analysis indicates that the displacement is associated positively with relocatees' depression level, and negatively with their self-rated health measured against a control group. In addition, a path analysis suggests that displacement also affects depression and self-rated health indirectly by changing social integration, socioeconomic status, and community resources. The importance of social integration as a protective mechanism, a factor that has been overlooked in past studies of population displacement, is highlighted in this study. Published by Elsevier Ltd.

  2. Particle displacement tracking for PIV

    Science.gov (United States)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  3. The morphological development of newly inundated intertidal areas: the mechanisms driving the early evolution of an estuarine environment designed and constructed by humans

    Science.gov (United States)

    Dale, Jonathan; Burgess, Heidi; Cundy, Andrew

    2017-04-01

    Intertidal saltmarsh and mudflat habitats are of global importance due to the ecosystem, economic and cultural services they provide. These services include wildlife habitat provision and species diversity, immobilisation of pollutants and protection from coastal flooding. Saltmarsh and mudflat environments are, however, being lost and degraded due to erosion caused by rising sea levels and increased storminess. These losses are exacerbated by anthropogenic influences including land reclamation, increased coastal development and the construction of coastal flood defences which prevent the landwards migration of saltmarsh and mudflat environments, resulting in coastal squeeze. To compensate for saltmarsh and mudflat losses areas of the coastal hinterland are being inundated by breaching defences and constructing new defences inland, thus extending or constructing new estuarine environments; a processes known as de-embankment or managed realignment. Morphological engineering and landscaping within managed realignment sites prior to site inundation varies depending on the aims of the scheme. However, there is a shortage of data on the morphological evolution within these sites post site inundation impeding the ability of coastal engineers to effectively design and construct future sites. To date there has been a focus on the colonisation of marine macro fauna and flora within newly inundated managed realignment sites, which can be relatively rapid and easily quantified. Little is known of the morphological evolution in response to altered sedimentary processes, its driving mechanisms and therefore the success and ecological sustainability of these sites. This study evaluates the post-inundation morphological development of the largest open coast managed realignment site in Europe, at Medmerry on the south coast of the United Kingdom. Inundated in September 2013, the Medmerry Managed Realignment Site consists of a mosaic of former agricultural land and areas of lower

  4. New Electromagnetic Force-Displacement Sensor

    OpenAIRE

    Benabdellah, Amine; Abbassi, Zakarya; Nakheli, Abdelrhani

    2016-01-01

    A new electromagnetic force-displacement sensor is presented. Its operating principle is based on the fundamental laws of electromagnetism (Faraday-Lenz law) and the mechanical properties of a spring. The active elements are two coils made by a wire of 60 µm in diameter. Using different wire diameters or different number of wire turns in the coil modify the intensity of the magnetic field and the sensor response. The average accuracy of the sensor is about ∆d=1µm, and as a force sensor is abo...

  5. Development of a XYθz 3-DOF nanopositioning stage with linear displacement amplification device

    Directory of Open Access Journals (Sweden)

    Chu Chih-Liang

    2017-01-01

    Full Text Available The main purpose of this study is to develop a XYθZ 3-DOF nanopositioning stage with linear displacement amplification device. This stage is used by three groups of linear displacement amplification device to composition, and thus achieves precise XYθZ 3-DOF movement. The linear displacement amplification device makes use of a symmetrical layer mechanism, toggle amplification mechanism and parallel guiding spring to composition, and with amplification capability. Then it uses an equilateral triangle way to set the three groups of linear displacement amplification device. Overall design uses the finite element software ANSYS 12.0 to analysis the displacement, stress and dynamic response of nanopositioning stage. Experiment demonstrated takes the laser interferometer as the standard of displacement measurement. The result of experiment measurement shows that the maximum XY axis displacement and θZ rotational angle travel of the stage is 36.5 μm, 32 μm and 265 arc sec.

  6. Character displacement in the fighting colours of Hetaerina damselflies.

    Science.gov (United States)

    Anderson, Christopher N; Grether, Gregory F

    2010-12-07

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated.

  7. Reliability of a MEMS Actuator Improved by Spring Corner Designs and Reshaped Driving Waveforms

    Directory of Open Access Journals (Sweden)

    Guo-Dung John Su

    2007-09-01

    Full Text Available In this paper, we report spring corner designs and driving waveforms to improve the reliability for a MEMS (Micro-Electro-Mechanical System actuator. In order to prevent the stiction problems, no stopper or damping absorber is adopted. Therefore, an actuator could travel long distance by electromagnetic force without any object in moving path to absorb excess momentum. Due to long displacement and large mass, springs of MEMS actuators tend to crack from weak points with high stress concentration and this situation degrades reliability performance. Stress distribution over different spring designs were simulated and a serpentine spring with circular and wide corner design was chosen due to its low stress concentration. This design has smaller stress concentration versus displacement. Furthermore, the resonant frequencies are removed from the driving waveform based on the analysis of discrete Fourier transfer function. The reshaped waveform not only shortens actuator switching time, but also ensures that the spring is in a small displacement region without overshooting so that the maximum stress is kept below 200 MPa. The experimental results show that the MEMS device designed by theses principles can survive 500 g (gravity acceleration shock test and pass 150 million switching cycles without failure.

  8. Reliability of a MEMS Actuator Improved by Spring Corner Designs and Reshaped Driving Waveforms.

    Science.gov (United States)

    Hsieh, Hsin-Ta; Su, Guo-Dung John

    2007-09-03

    In this paper, we report spring corner designs and driving waveforms to improve the reliability for a MEMS (Micro-Electro-Mechanical System) actuator. In order to prevent the stiction problems, no stopper or damping absorber is adopted. Therefore, an actuator could travel long distance by electromagnetic force without any object in moving path to absorb excess momentum. Due to long displacement and large mass, springs of MEMS actuators tend to crack from weak points with high stress concentration and this situation degrades reliability performance. Stress distribution over different spring designs were simulated and a serpentine spring with circular and wide corner design was chosen due to its low stress concentration. This design has smaller stress concentration versus displacement. Furthermore, the resonant frequencies are removed from the driving waveform based on the analysis of discrete Fourier transfer function. The reshaped waveform not only shortens actuator switching time, but also ensures that the spring is in a small displacement region without overshooting so that the maximum stress is kept below 200 MPa. The experimental results show that the MEMS device designed by theses principles can survive 500 g (gravity acceleration) shock test and pass 150 million switching cycles without failure.

  9. Dissipation and displacement of hotspots in reaction-diffusion models of crime.

    Science.gov (United States)

    Short, Martin B; Brantingham, P Jeffrey; Bertozzi, Andrea L; Tita, George E

    2010-03-02

    The mechanisms driving the nucleation, spread, and dissipation of crime hotspots are poorly understood. As a consequence, the ability of law enforcement agencies to use mapped crime patterns to design crime prevention strategies is severely hampered. We also lack robust expectations about how different policing interventions should impact crime. Here we present a mathematical framework based on reaction-diffusion partial differential equations for studying the dynamics of crime hotspots. The system of equations is based on empirical evidence for how offenders move and mix with potential victims or targets. Analysis shows that crime hotspots form when the enhanced risk of repeat crimes diffuses locally, but not so far as to bind distant crime together. Crime hotspots may form as either supercritical or subcritical bifurcations, the latter the result of large spikes in crime that override linearly stable, uniform crime distributions. Our mathematical methods show that subcritical crime hotspots may be permanently eradicated with police suppression, whereas supercritical hotspots are displaced following a characteristic spatial pattern. Our results thus provide a mechanistic explanation for recent failures to observe crime displacement in experimental field tests of hotspot policing.

  10. Linear Back-Drive Differentials

    Science.gov (United States)

    Waydo, Peter

    2003-01-01

    Linear back-drive differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-drive differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-drive differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-drive differentials would operate according to established principles of power ball screws and linear-motion drives, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-drive differentials is the possibility of designing them to drive or back-drive with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can drive a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-drive differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-drive differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would drive the nut in linear motion. The nut, in turn, would back-drive the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.

  11. How to avoid simulation sickness in virtual environments during user displacement

    Science.gov (United States)

    Kemeny, A.; Colombet, F.; Denoual, T.

    2015-03-01

    Driving simulation (DS) and Virtual Reality (VR) share the same technologies for visualization and 3D vision and may use the same technics for head movement tracking. They experience also similar difficulties when rendering the displacements of the observer in virtual environments, especially when these displacements are carried out using driver commands, including steering wheels, joysticks and nomad devices. High values for transport delay, the time lag between the action and the corresponding rendering cues and/or visual-vestibular conflict, due to the discrepancies perceived by the human visual and vestibular systems when driving or displacing using a control device, induces the so-called simulation sickness. While the visual transport delay can be efficiently reduced using high frequency frame rate, the visual-vestibular conflict is inherent to VR, when not using motion platforms. In order to study the impact of displacements on simulation sickness, we have tested various driving scenarios in Renault's 5-sided ultra-high resolution CAVE. First results indicate that low speed displacements with longitudinal and lateral accelerations under a given perception thresholds are well accepted by a large number of users and relatively high values are only accepted by experienced users and induce VR induced symptoms and effects (VRISE) for novice users, with a worst case scenario corresponding to rotational displacements. These results will be used for optimization technics at Arts et Métiers ParisTech for motion sickness reduction in virtual environments for industrial, research, educational or gaming applications.

  12. Shifted axis angular positioning mechanisms – unconventional use of exact constraint design

    OpenAIRE

    Szykiedans Ksawery; Bujwan Maciej

    2018-01-01

    Paper presents some remarks about designing angular positioners having significant angular displacement and shifted axis of rotation. Those driving mechanism are useful in specific applications where mechanism wraps around other object or there is a need of rotation around virtual axis. Examples of those applications like orthotic robots or gimbals for panoramic motions where developed at Faculty of Mechatronics WUT. Usage of exact constraint method was described including its influence to a ...

  13. Control rod drive

    International Nuclear Information System (INIS)

    Watando, Kosaku; Tanaka, Yuzo; Mizumura, Yasuhiro; Hosono, Kazuya.

    1975-01-01

    Object: To provide a simple and compact construction of an apparatus for driving a drive shaft inside with a magnetic force from the outside of the primary system water side. Structure: The weight of a plunger provided with an attraction plate is supported by a plunger lift spring means so as to provide a buffer action at the time of momentary movement while also permitting the load on lift coil to be constituted solely by the load on the drive shaft. In addition, by arranging the attraction plate and lift coil so that they face each other with a small gap there-between, it is made possible to reduce the size and permit efficient utilization of the attracting force. Because of the small size, cooling can be simply carried out. Further, since there is no mechanical penetration portion, there is no possibility of leakage of the primary system water. Furthermore, concentration of load on a latch pin is prevented by arranging so that with a structure the load of the control rod to be directly beared through the scrum latch. (Kamimura, M.)

  14. Safe driving for teens

    Science.gov (United States)

    Driving and teenagers; Teens and safe driving; Automobile safety - teenage drivers ... MAKE A COMMITTMENT TO SAFETY Teens also need to commit to being safe and responsible drivers in order to improve the odds in their favor. Reckless driving ...

  15. A thermal modelling of displacement cascades in uranium dioxide

    Science.gov (United States)

    Martin, G.; Garcia, P.; Sabathier, C.; Devynck, F.; Krack, M.; Maillard, S.

    2014-05-01

    The space and time dependent temperature distribution was studied in uranium dioxide during displacement cascades simulated by classical molecular dynamics (MD). The energy for each simulated radiation event ranged between 0.2 keV and 20 keV in cells at initial temperatures of 700 K or 1400 K. Spheres into which atomic velocities were rescaled (thermal spikes) have also been simulated by MD to simulate the thermal excitation induced by displacement cascades. Equipartition of energy was shown to occur in displacement cascades, half of the kinetic energy of the primary knock-on atom being converted after a few tenths of picoseconds into potential energy. The kinetic and potential parts of the system energy are however subjected to little variations during dedicated thermal spike simulations. This is probably due to the velocity rescaling process, which impacts a large number of atoms in this case and would drive the system away from a dynamical equilibrium. This result makes questionable MD simulations of thermal spikes carried out up to now (early 2014). The thermal history of cascades was compared to the heat equation solution of a punctual thermal excitation in UO2. The maximum volume brought to a temperature above the melting temperature during the simulated cascade events is well reproduced by this simple model. This volume eventually constitutes a relevant estimate of the volume affected by a displacement cascade in UO2. This definition of the cascade volume could also make sense in other materials, like iron.

  16. Tendon displacements during voluntary and involuntary finger movements.

    Science.gov (United States)

    van Beek, Nathalie; Gijsbertse, Kaj; Selles, Ruud W; de Korte, Chris L; Veeger, DirkJan H E J; Stegeman, Dick F; Maas, Huub

    2018-01-23

    In the human hand, independent movement control of individual fingers is limited. One potential cause for this is mechanical connections between the tendons and muscle bellies corresponding to the different fingers. The aim of this study was to determine the tendon displacement of the flexor digitorum superficialis (FDS) of both the instructed and the neighboring, non-instructed fingers during single finger flexion movements. In nine healthy subjects (age 22-29 years), instructed and non-instructed FDS finger tendon displacement of the index, middle and ring finger was measured using 2D ultrasound analyzed with speckle tracking software in two conditions: active flexion of all finger joints with all fingers free to move and active flexion while the non-instructed fingers were restricted. Our results of the free movement protocol showed an average tendon displacement of 27 mm for index finger flexion, 21 mm for middle finger flexion and 17 mm for ring finger flexion. Displacements of the non-instructed finger tendons (≈12 mm) were higher than expected based of the amount of non-instructed finger movement. In the restricted protocol, we found that, despite minimal joint movements, substantial non-instructed finger tendon displacement (≈9 mm) was still observed, which was interpreted as a result of tendon strain. When this strain component was subtracted from the tendon displacement of the non-instructed fingers during the free movement condition, the relationship between finger movement and tendon displacement of the instructed and non-instructed finger became comparable. Thus, when studying non-instructed finger tendon displacement it is important to take tendon strain into consideration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Dynamic protein assembly by programmable DNA strand displacement

    Science.gov (United States)

    Chen, Rebecca P.; Blackstock, Daniel; Sun, Qing; Chen, Wilfred

    2018-03-01

    Inspired by the remarkable ability of natural protein switches to sense and respond to a wide range of environmental queues, here we report a strategy to engineer synthetic protein switches by using DNA strand displacement to dynamically organize proteins with highly diverse and complex logic gate architectures. We show that DNA strand displacement can be used to dynamically control the spatial proximity and the corresponding fluorescence resonance energy transfer between two fluorescent proteins. Performing Boolean logic operations enabled the explicit control of protein proximity using multi-input, reversible and amplification architectures. We further demonstrate the power of this technology beyond sensing by achieving dynamic control of an enzyme cascade. Finally, we establish the utility of the approach as a synthetic computing platform that drives the dynamic reconstitution of a split enzyme for targeted prodrug activation based on the sensing of cancer-specific miRNAs.

  18. Magnetic driving energy of the tearing mode

    International Nuclear Information System (INIS)

    Adler, E.A.; Kulsrud, R.M.; White, R.B.

    1979-10-01

    The change in the magnetic energy density produced by a tearing mode is calculated exactly. The driving energy for the mode is found to come entirely from the region inside the tearing layer, although there is also a displacement of energy in the outer region which integrates to zero. The total change in magnetic energy is exactly equal to the change in a quadratic form related to a variational principle for the full resistive equations

  19. Colombia: durable solutions for the forcibly displaced

    Directory of Open Access Journals (Sweden)

    Amaya Valcárcel

    2017-10-01

    Full Text Available Colombia has a sophisticated body of law and a wealth of experience in the development of policies for the forcibly displaced. However, numerous obstacles stand in the way of attaining permanent solutions to displacement.

  20. Branching random walks with displacements coming from a power law

    Indian Academy of Sciences (India)

    Parthanil Roy Joint work with Ayan Bhattacharya and Rajat Subhra Hazra

    2015-07-04

    Jul 4, 2015 ... Branching Random Walk: Description in Words. Parthanil Roy (I.S.I.). Branching random walk. July 04, 2015. 6 / 14 ... independent of each other. This gives rise to the Generation 1. The displacements are (positive and) independent of the branching mechanism. Parthanil Roy (I.S.I.). Branching random walk.

  1. Analytical expression for an optimised link bar mechanism for a beta-type Stirling engine

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Bovin, Jonas Kabell

    2007-01-01

    The design of a mechanism for kinematic beta-type Stirling engines, where the displacer piston and the working piston share the same cylinder, is complicated. A well-known solution is the rhombic drive, but this solution depends on oil lubrication because of the gear wheels connecting the two...... counter rotating crank shafts. In a hermetically sealed Stirling engine it is an advantage to avoid oil in the crank case, making the application of the rhombic drive difficult. In this paper, another crank mechanism is presented, which has been developed for a 9 kW single cylinder engine. The new crank...... mechanism is a further development of the mechanism in a previous 9 kW engine. The crank mechanism for the beta-type Stirling engine is based on two four-link straight line mechanisms pointing up and down, respectively. The mechanism pointing upwards is connected to the working piston, while the mechanism...

  2. A fibre optic displacement sensor

    OpenAIRE

    Sohlström, Hans; Holm, Ulf

    1982-01-01

    Fibre optics is beginning to find use for sensing purposes. Fibre optic sensors have many interesting features, e.g., their immunity to interference from electromagnetic fields. The paper briefly discusses different sensor principles. A displacement sensor using multimode, step index fibres is desccribed. Measurement data showing a resolution of 0.05 nm/sqrt(Hz) in a 150 µm linear range is given. In this sensor, the light coupling between two fibre ends varies with the position of a movable ...

  3. Time varying behavior of the loudspeaker suspension: Displacement level dependency

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Pedersen, Bo Rohde

    2009-01-01

    The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly...... by how much the suspension has been stretched, i.e. the maximum displacement, is investigated. For this purpose the changes in compliance are measured when exposing the speaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal excitation...

  4. A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

    Science.gov (United States)

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  5. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2011-12-01

    Full Text Available Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  6. On the analysis of competitive displacement in dengue disease transmission

    Science.gov (United States)

    Wijaya, Karunia P.; Nuraini, Nuning; Soewono, Edy; Handayani, Dewi

    2014-03-01

    We study a host-vector model involving the interplay of competitive displacement mechanism in a specific DENV serotype, both in human blood and mosquito blood. Using phylogenetic analysis, world virologists investigate the severe manifestations of dengue fever caused by the displacements within weakly virulent pathogens (native strains) by more virulent pathogens (invasive strains) in one serotype. We construct SIR model for human and SI model for mosquito to explore the key determinants of those displacements. Analysis of nonnegativity and boundedness of the solution as well as the basic reproduction number (R0) are taken into account for verifying the model into biological meaningfulness. To generate predictions of the outcomes of control strategies, we derive an optimal control model which involves two control apparatus: fluid infusion (for human) and fumigation (for vector). Numerical results show the dynamics of host-vector in an observation period, both under control and without control.

  7. Hurried driving: Relationship to distress tolerance, driver anger, aggressive and risky driving in college students.

    Science.gov (United States)

    Beck, Kenneth H; Daughters, Stacey B; Ali, Bina

    2013-03-01

    Being a hurried driver is associated with a variety of risky driving behaviors, yet the mechanisms underlying this behavior remain unknown. Distress tolerance, defined as an individual's capability to experience and endure negative emotional states, was examined as a predictor of hurried driving among 769 college students. Results indicate that after controlling for age, gender, race, ethnicity, the student's year in school, their grade point average, driving frequency, angry driving, aggressive driving as well as other forms of self-reported risky driving; hurried driving was significantly associated with lower levels of distress tolerance. Hurried drivers also reported greater levels of frustration and impatience with other drivers, suggesting that they have difficulty in withstanding or coping with negative psychological states when driving. Traditional traffic safety campaigns that emphasize enforcement may be less successful with these drivers. The need to develop campaigns that address the affective coping abilities that contribute to this behavioral pattern is discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Overhead Transmission Lines Deicing under Different Incentive Displacement

    Directory of Open Access Journals (Sweden)

    Qing He

    2014-01-01

    Full Text Available Overhead transmission line icing is one of the main factors affecting safety and reliability of power grid. This paper proposed an excitation deicing method of iced wire and theoretically revealed the ice removal mechanism under displacement excitation conditions, by taking the LGJ-70/10 glaze icing wire as the 3D model and analyzing and studying its dynamic response under the effect of displacement excitation. The simulation results show that the stress of wire icing area is enlarged with the increase of excitation displacement and frequency. Through the comparison of the compression strength experimental results on a series of different iced wires in low temperature environment, the authors found out that the stress generated from the wire icing area is greater than the crushing strength of the ice within the scope of the calculation parameters, which proved the validity and the feasibility of the method, and finally the suitable excitation displacement is determined. Following studies show that, as far as possible, it is necessary to reduce the incentive displacement and also to select the appropriate constraint length in order to avoid the line jumping that may be caused by large span ice shedding.

  9. Predicting target displacements using ultrasound elastography and finite element modeling.

    Science.gov (United States)

    op den Buijs, Jorn; Hansen, Hendrik H G; Lopata, Richard G P; de Korte, Chris L; Misra, Sarthak

    2011-11-01

    Soft tissue displacements during minimally invasive surgical procedures may cause target motion and subsequent misplacement of the surgical tool. A technique is presented to predict target displacements using a combination of ultrasound elastography and finite element (FE) modeling. A cubic gelatin/agar phantom with stiff targets was manufactured to obtain pre- and post-loading ultrasound radio frequency (RF) data from a linear array transducer. The RF data were used to compute displacement and strain images, from which the distribution of elasticity was reconstructed using an inverse FE-based approach. The FE model was subsequently used to predict target displacements upon application of different boundary and loading conditions to the phantom. The influence of geometry was investigated by application of the technique to a breast-shaped phantom. The distribution of elasticity in the phantoms as determined from the strain distribution agreed well with results from mechanical testing. Upon application of different boundary and loading conditions to the cubic phantom, the FE model-predicted target motion were consistent with ultrasound measurements. The FE-based approach could also accurately predict the displacement of the target upon compression and indentation of the breast-shaped phantom. This study provides experimental evidence that organ geometry and boundary conditions surrounding the organ are important factors influencing target motion. In future work, the technique presented in this paper could be used for preoperative planning of minimally invasive surgical interventions.

  10. Characterization of the elastic displacement demand: Case study - Sofia city

    International Nuclear Information System (INIS)

    Paskaleva, I.; Kouteva, M.; Vaccari, F.; Panza, G.F.

    2008-02-01

    The results of the study on the seismic site response in a part of the metropolitan Sofia are discussed. The neo-deterministic seismic hazard assessment procedure has been used to compute realistic synthetic waveforms considering four earthquake scenarios, with magnitudes M = 3.7, M = 6.3 and M = 7.0. Source and site specific ground motion time histories are computed along three investigated cross sections, making use of the hybrid approach, combining the modal summation technique and the finite differences scheme. Displacement and acceleration response spectra are considered. These results are validated against the design elastic displacement response spectra and displacement demand, recommended in Eurocode 8. The elastic response design spectrum from the standard pseudo-acceleration, versus natural period, Tn, format is converted to the Sa - Sd format. The elastic displacement response spectra and displacement demand are discussed with respect to the earthquake magnitude, the seismic source-to-site distance, seismic source mechanism, and the local geological site conditions. (author)

  11. Modeling and Positioning of a PZT Precision Drive System

    OpenAIRE

    Liu, Che; Guo, Yanling

    2017-01-01

    The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circu...

  12. Displacement of the pelvis during human walking : experimental data and model predictions

    NARCIS (Netherlands)

    Zijlstra, W; Hof, AL

    1997-01-01

    Displacements of the pelvis during treadmill walking were studied in dependence of walking speed, stride frequency and stride length. Displacement curves per stride cycle were described by means of harmonic analysis. Simple mechanical, or geometrical models of the body's center of mass (COM)

  13. DISPLACEMENT BASED SEISMIC DESIGN CRITERIA

    Energy Technology Data Exchange (ETDEWEB)

    HOFMAYER,C.H.

    1999-03-29

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

  14. Shore line displacement in Oeregrundsgrepen

    International Nuclear Information System (INIS)

    Brydsten, Lars

    1999-12-01

    This report is a part of the SKB project 'SAFE' (Safety Assessment of the Final Repository of Radioactive Operational Waste). The aim of project SAFE is to update the previous safety analysis of SFR-1. The analysis is to be presented to the Swedish authorities not later than the end of 2000. SFR-1 is a facility for disposal of low and intermediate level radioactive waste and is situated in bedrock beneath the Baltic Sea, 1 km off the coast near the Forsmark nuclear power plant in Northern Uppland. The shore displacement in the Oeregrundsgrepen area is at present approximately 60 cm per 100 years and is slowly decreasing, but will still be substantial for many thousands of years. Since Oeregrundsgrepen is a relatively shallow part of the Bothnian Sea, the positive shore displacement will greatly effect the proportions of land and sea in the future. Within 2000 years (4000 AD) half of the current water area in Oeregrundsgrepen will be land and the water volume will be decreased with two thirds. At 7000 AD, the whole Oeregrundsgrepen area will be without brackish water. The effects on the landscape evolution due to shore displacement in the Oeregrundsgrepen area are illustrated in a chronological series of digital maps in Power Point format available saved on the supplied CD-rom and entitled 'Elevation.ppt '. The bedrock tectonics in the area are in two dominating directions: one northern that can be seen in the west shoreline of the island Graesoe and one in a north-westerly direction seen in the shoreline of the mainland. Many of the large basins that will be established in the area due to the shore displacement will be elongated in one of these directions. Some of the basins are relatively shallow and therefore probably will be totally filled with organic rich sediments and will form peat or bogs. Other basins, especially Graesoeraennan (the deep channel on the west side of Graesoe) are deep basins and will form a long chain of deep lakes. One of the deeper basins

  15. Primary shield displacement and bowing

    International Nuclear Information System (INIS)

    Scott, K.V.

    1978-01-01

    The reactor primary shield is constructed of high density concrete and surrounds the reactor core. The inlet, outlet and side primary shields were constructed in-place using 2.54 cm (1 in) thick steel plates as the forms. The plates remained as an integral part of the shields. The elongation of the pressure tubes due to thermal expansion and pressurization is not moving through the inlet nozzle hardware as designed but is accommodated by outward displacement and bowing of the inlet and outlet shields. Excessive distortion of the shields may result in gas seal failures, intolerable helium gas leaks, increased argon-41 emissions, and shield cooling tube failures. The shield surveillance and testing results are presented

  16. Displacement Based Seismic Design Criteria

    International Nuclear Information System (INIS)

    Costello, J.F.; Hofmayer, C.; Park, Y.J.

    1999-01-01

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration

  17. Possible displacement of mercury's dipole

    International Nuclear Information System (INIS)

    Ng, K.H.; Beard, D.B.

    1979-01-01

    Earlier attempts to model the Hermean magnetospheric field based on a planet-centered magnetic multipole field have required the addition of a quadrupole moment to obtain a good fit to space vehicle observations. In this work we obtain an equally satisfactory fit by assuming a null quadrupole moment and least squares fitting of the displacement of the planetary dipole from the center of the planet. We find a best fit for a dipole displacement from the planet center of 0.033 R/sub m/ away from the solar direction, 0.025 R/sub m/ toward dawn in the magnetic equatorial plane, and 0.189 R/sub m/ northward along the magnetic dipole axis, where R/sub m/ is the planet radius. Therefore the presence of a magnetic quadrupole moment is not ruled out. The compressed dipole field more completely represents the field in the present work than in previous work where the intrinsic quadrupole field was not included in the magnetopause surface and field calculations. Moreover, we have corrected a programing error in previous work in the computation of dipole tilt lambda away from the sun. We find a slight increase for the planet dipole moment of 190γR/sub m/ 3 and a dipole tilt angle lambda away from the sun. We find a slight increase for the planet moment of 190γR/sub m/ 3 and a dipole tilt angle lambda of only 1.2 0 away from the sun. All other parameters are essentially unchanged

  18. Distracted driving due to visual working memory load.

    Science.gov (United States)

    2014-07-01

    In an attempt to understand the : specific mechanism by which distractions (such as cell : - : phone use) can interfere with : driving, this work tested the idea that driving performance depends on available space within visual short : - : term memor...

  19. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    OpenAIRE

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2011-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both h...

  20. Extended displacement discontinuity method for analysis of cracks in 2D thermal piezoelectric semiconductors

    Science.gov (United States)

    Zhao, MingHao; Pan, YiBo; Fan, CuiYing; Xu, GuangTao

    2017-08-01

    The extended displacement discontinuities method has previously been used for crack analysis of elastic materials, piezoelectric media, magneto-electro-elastic media and piezoelectric semiconductors. Here, this method is extended to study cracks in two-dimensional n-type thermal piezoelectric semiconductors. The extended displacement discontinuities include the conventional displacement discontinuity, electric potential discontinuity, carrier density discontinuity, as well as temperature discontinuity across crack faces; correspondingly, the extended stresses represent conventional stress, electric displacement, electric current, and heat flux. Employing a Fourier transform, the fundamental solutions for a line crack under uniformly distributed extended displacement discontinuities on the crack faces are derived under mechanical, electrical, and heat loading. Based on the obtained fundamental solutions, an extended displacement discontinuity boundary element method is developed. The stress and heat flux intensity factors at the crack tip are calculated under different combined loadings.

  1. Earthquake related displacement fields near underground facilities

    International Nuclear Information System (INIS)

    Pratt, H.R.; Zandt, G.; Bouchon, M.

    1979-04-01

    Relative displacements of rock masses are evaluated in terms of geological evidence, seismological evidence, data from simulation experiments, and analytical predictive models. Numerical models have been developed to determine displacement fields as a function of depth, distance, and azimuth from an earthquake source. Computer calculations for several types of faults indicate that displacements decrease rapidly with distance from the fault, but that displacements can either increase or decrease as a function of depth depending on the type and geometry of the fault. For long shallow vertical strike-slip faults the displacement decreases markedly with depth. For square strike slip faults and for dip slip faults displacement does not decrease as markedly with depth. Geologic structure, material properties, and depth affect the seismic source spectrum. Amplification of the high frequencies of shear waves is larger by a factor of about 2 for layered geologic models than for an elastic half space

  2. Dementia and driving

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000028.htm Dementia and driving To use the sharing features on ... please enable JavaScript. If your loved one has dementia , deciding when they can no longer drive may ...

  3. Control rod drives

    International Nuclear Information System (INIS)

    Shimano, Kunio; Nakamura, Akira; Mizuguchi, Koji; Sakai, Kazuhito; Mitsui, Hisayasu.

    1994-01-01

    The present invention concerns upper-built-in type control rod drives of a BWR type reactor. Namely, high temperature linear motor driving type control rod drives are disposed in an upper space of the reactor pressure vessel, which generates electromagnetic power. In usual driving of control rods, driving shafts connected with control rods by a high temperature linear motor driving system comprising a driving shaft having an iron core inserted therein and electromagnetic coils is vertically moved to insert/withdraw the control rods to and from the reactor core. Upon occurrence of reactor scram, electric power source is interrupted, and the control rods are rapidly inserted to the reactor core. According to the present invention, since the control rod drives are disposed in the space above the reactor pressure vessel, pipelines or equipments passing through the bottom of the reactor pressure vessel can be saved. As a result, operation for maintenance and inspection is facilitated. (I.S.)

  4. Some Stars are Totally Metal: A New Mechanism Driving Dust across Star-forming Clouds, and Consequences for Planets, Stars, and Galaxies

    Science.gov (United States)

    Hopkins, Philip F.

    2014-12-01

    Dust grains in neutral gas behave as aerodynamic particles, so they can develop large local density fluctuations entirely independent of gas density fluctuations. Specifically, gas turbulence can drive order-of-magnitude "resonant" fluctuations in the dust density on scales where the gas stopping/drag timescale is comparable to the turbulent eddy turnover time. Here we show that for large grains (size >~ 0.1 μm, containing most grain mass) in sufficiently large molecular clouds (radii >~ 1-10 pc, masses >~ 104 M ⊙), this scale becomes larger than the characteristic sizes of prestellar cores (the sonic length), so large fluctuations in the dust-to-gas ratio are imprinted on cores. As a result, star clusters and protostellar disks formed in large clouds should exhibit significant abundance spreads in the elements preferentially found in large grains (C, O). This naturally predicts populations of carbon-enhanced stars, certain highly unusual stellar populations observed in nearby open clusters, and may explain the "UV upturn" in early-type galaxies. It will also dramatically change planet formation in the resulting protostellar disks, by preferentially "seeding" disks with an enhancement in large carbonaceous or silicate grains. The relevant threshold for this behavior scales simply with cloud densities and temperatures, making straightforward predictions for clusters in starbursts and high-redshift galaxies. Because of the selective sorting by size, this process is not necessarily visible in extinction mapping. We also predict the shape of the abundance distribution—when these fluctuations occur, a small fraction of the cores may actually be seeded with abundances Z ~ 100 langZrang such that they are almost "totally metal" (Z ~ 1)! Assuming the cores collapse, these totally metal stars would be rare (1 in ~104 in clusters where this occurs), but represent a fundamentally new stellar evolution channel.

  5. Point Coupled Displacement Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Real-time displacement measurement techniques are needed to acquire aerodynamic and structural system characteristics in flight. This proposal describes the...

  6. Percutaneous Fixation of Displaced Calcaneal Fracture

    Directory of Open Access Journals (Sweden)

    Yeung Yip-Kan

    2011-06-01

    Conclusion: Percutaneous fixation of displaced tongue-type calcaneal fractures is an effective treatment with acceptable clinical outcome, short hospital stay, minimal skin complications, and quick recovery.

  7. Simple Driving Techniques

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    2002-01-01

    -like language. Our aim is to extract a simple notion of driving and show that even in this tamed form it has much of the power of more general notions of driving. Our driving technique may be used to simplify functional programs which use function composition and will often be able to remove intermediate data...

  8. A Sclerostin super-producer cell line derived from the human cell line SaOS-2: a new tool for the study of the molecular mechanisms driving Sclerostin expression.

    Science.gov (United States)

    Pérez-Campo, Flor M; Sañudo, Carolina; Delgado-Calle, Jesús; Arozamena, Jana; Zarrabeitia, María T; Riancho, José A

    2014-08-01

    Sclerostin, the product of the SOST gene, is a key regulator of bone homeostasis. Sclerostin interferes with the Wnt signalling pathway and, therefore, has a negative effect on bone formation. Although the importance of sclerostin in bone homeostasis is well established, many aspects of its biology are still unknown. Due to its restricted pattern of expression, in vitro studies of SOST gene regulation are technically challenging. Furthermore, a more profound investigation of the molecular mechanism controlling sclerostin expression has been hampered by the lack of a good human in vitro model. Here, we describe two cell lines derived from the human osteosarcoma cell line SaOS-2 that produce elevated levels of sclerostin. Analysis of the super-producer cell lines showed that sclerostin levels were still reduced in response to parathyroid hormone treatment or in response to mechanical loading, indicating that these regulatory mechanisms were not affected in the presented cell lines. In addition, we did not find differences between the promoter or ECR5 sequences of our clones and the SaOS-2 parental line. However, the methylation of the proximal CpG island located at the SOST promoter was lower in the super-producer clones, in agreement with a higher level of SOST transcription. Although the underlying biological causes of the elevated levels of sclerostin production in this cell line are not yet clear, we believe that it could be an extremely useful tool to study the molecular mechanisms driving sclerostin expression in humans.

  9. Rotating Drive for Electrical-Arc Machining

    Science.gov (United States)

    Fransen, C. D.

    1986-01-01

    Rotating drive improves quality of holes made by electrical-arc machining. Mechanism (Uni-tek, rotary head, or equivalent) attached to electrical-arc system. Drive rotates electrode as though it were mechanical drill, while an arc disintegrates metal in workpiece, thereby creating hole. Rotating electrode method often used in electric-discharge machining. NASA innovation is application of technique to electrical-arc machining.

  10. High performance AC drives

    CERN Document Server

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  11. Effects of Fault Displacement on Emplacement Drifts

    International Nuclear Information System (INIS)

    Duan, F.

    2000-01-01

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10 -5 adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M and O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure

  12. Indexing mechanisms

    International Nuclear Information System (INIS)

    Wood, A.G.; Parker, G.E.; Berry, R.

    1976-01-01

    It is stated that the indexing mechanism described can be used in a nuclear reactor fuel element inspection rig. It comprises a tubular body adapted to house a canister containing a number of fuel elements located longtitudinally, and has two chucks spaced apart for displacing the fuel elements longitudinally in a stepwise manner, together with a plunger mechanism for displacing them successively into the chucks. A measuring unit is located between the chucks for measuring the diameter of the fuel elements at intervals about their circumferences, and a secondary indexing mechanism is provided for rotating the measuring unit in a stepwise manner. (U.K.)

  13. Intravital imaging reveals new ancillary mechanisms co-opted by cancer cells to drive tumor progression [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Claire Vennin

    2016-05-01

    Full Text Available Intravital imaging is providing new insights into the dynamics of tumor progression in native tissues and has started to reveal the layers of complexity found in cancer. Recent advances in intravital imaging have allowed us to look deeper into cancer behavior and to dissect the interactions between tumor cells and the ancillary host niche that promote cancer development. In this review, we provide an insight into the latest advances in cancer biology achieved by intravital imaging, focusing on recently discovered mechanisms by which tumor cells manipulate normal tissue to facilitate disease progression.

  14. Mechanism

    Directory of Open Access Journals (Sweden)

    Yao Yu

    2010-01-01

    Full Text Available The kinematics analysis method of a novel 3-DOF wind tunnel mechanism based on cable-driven parallel mechanism is provided. Rodrigues' parameters are applied to express the transformation matrix of the wire-driven mechanism in the paper. The analytical forward kinematics model is described as three quadratic equations using three Rodridgues' parameters based on the fundamental theory of parallel mechanism. Elimination method is used to remove two of the variables, so that an eighth-order polynomial with one variable is derived. From the equation, the eight sets of Rodridgues' parameters and corresponding Euler angles for the forward kinematical problem can be obtained. In the end, numerical example of both forward and inverse kinematics is included to demonstrate the presented forward-kinematics solution method. The numerical results show that the method for the position analysis of this mechanism is effective.

  15. 40 CFR 205.153 - Engine displacement.

    Science.gov (United States)

    2010-07-01

    ... 205.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine..., displacement means the maximum volume of a combustion chamber between two rotor tip seals minus the minimum...

  16. Displaced Homemakers: Vo-Tech Workshop Guide.

    Science.gov (United States)

    Peltier, Wanda Jo

    Written for displaced homemaker programs in vocational-technical schools, this curriculum contains material designed so that instructors can prepare student manuals appropriate to almost any educational support situation for displaced homemakers. An overview provides information on special needs groups, curriculum use, and resources and sample…

  17. Prolonged displacement may compromise resilience in Eritrean ...

    African Journals Online (AJOL)

    Objective: to assess the impact of prolonged displacement on the resilience of Eritrean mothers. Methods: an adapted SOC scale (short form) was administered. Complementary qualitative data were gathered from study participants' spontaneous reactions to and commentaries on the SOC scale. Results: Displaced ...

  18. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and ...

  19. Seismic displacement of gravity retaining walls

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-08-01

    Full Text Available Seismic displacement of gravity walls had been studied using conventional static methods for controlled displacement design. In this study plain strain numerical analysis is performed using Plaxis dynamic program where prescribed displacement is applied at the bottom boundary of the soil to simulate the applied seismic load. Constrained absorbent side boundaries are introduced to prevent any wave reflection. The studied soil is chosen dense granular sand and modeled as elasto-plastic material according to Mohr–Column criteria while the gravity wall is assumed elastic. By comparing the resulted seismic wall displacements calculated by numerical analysis for six historical ground motions with that calculated by the pseudo-static method, it is found that numerical seismic displacements are either equal to or greater than corresponding pseudo-static values. Permissible seismic wall displacement calculated by AASHTO can be used for empirical estimation of seismic displacement. It is also found that seismic wall displacement is directly proportional with the positive angle of inclination of the back surface of the wall, soil flexibility and with the earthquake maximum ground acceleration. Seismic wall sliding is dominant and rotation is negligible for rigid walls when the ratio between the wall height and the foundation width is less than 1.4, while for greater ratios the wall becomes more flexible and rotation (rocking increases till the ratio reaches 1.8 where overturning is susceptible to take place. Cumulative seismic wall rotation increases with dynamic time and tends to be constant at the end of earthquake.

  20. Video Games, Adolescents, and the Displacement Effect

    Science.gov (United States)

    Fisher, Carla Christine

    2012-01-01

    The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

  1. Etiopathogenesis of abomasal displacement in cattle

    Directory of Open Access Journals (Sweden)

    Šamanc Horea

    2003-01-01

    Full Text Available Abomasal displacement presents topographic gastropathy, where this organ has changed its position, and there is simultaneous dilatation which can vary in intensity. The incidence of this disorder in herds of high-yield dairy cows varies to a great degree (1 to 18 %. Abomasal displacement was established in herds of East-Frisian cows in 1 to 3% animals, and in Holstein cow herds in 5 to 18 % animals. The most frequent abomasal displacement is to the left (88%. There is significant seasonal variation in the incidence of abomasal displacement. About two-thirds of cases of abomasal displacement are diagnosed from October until April. The disorder appears more frequently in cows with repeated lactations. It has been established that it appears after the first calving in 27.8% cases, after the second to fifth calving in 66.7% cases, and after the sixth and seventh calving in 5.5% of the cows. The response of endocrine pancreas B-cells for insulin secretion to hyperglycaemia caused by applying an excess-glucose test is reduced in cows with left abomasal displacement, and there is constant hyperglycaemia in cows with right abomasal displacement. The excess-glucose test indicates a disrupted function of the endocrine pancreas in diseased animals. It has been determined through examinations of Aml genotypes in Holstein cow herds in connection with the appearance of abomasal displacement, that the occurrence of this disorder cannot be attributed to a genetic predisposition.

  2. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    Abstract. We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc. (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method.

  3. Displacement and resonance behaviors of a piezoelectric diaphragm driven by a double-sided spiral electrode

    KAUST Repository

    Shen, Zhiyuan

    2012-04-03

    This paper presents the design of a lead zirconate titanate (PZT) diaphragm actuated by double-sided patterned electrodes. Au/Cr electrodes were deposited on bulk PZT wafers by sputtering while patterned by a lift-off process. SU-8 thick film was used to form the structural layer. Double-spiral electrode induced in-plane poling and piezoelectric elongation are converted to an out-of-plane displacement due to the confined boundary condition. The influence of different drive configurations and electrode parameters on deflection has been calculated by finite element methods (FEM) using a uniform field model. Impedance and quasi-static displacement spectra of the diaphragm were measured after poling. Adouble-sided patterned electrode diaphragm can be actuated by more drive configurations than a single-sided one. Compared with a single-sided electrode drive, a double-sided out-of-phase drive configuration increases the coupling coefficient of the fundamental resonance from 7.6% to 11.8%. The displacement response of the diaphragm increases from 2.6 to 8.6nmV 1. Configurations including the electric field component perpendicular to the poling direction can stimulate shear modes of the diaphragm. © 2012 IOP Publishing Ltd.

  4. Design and Preliminary Results of a Feedback Circuit for Plasma Displacement Control in IR-T1 Tokamak

    International Nuclear Information System (INIS)

    TalebiTaher, A.; Ghoranneviss, M.; Tarkeshian, R.; Salem, M. K.; Khorshid, P.

    2008-01-01

    Since displacement is very important for plasma position control, in IR-T1 tokamak a combination of two cosine coils and two saddle sine coils is used for horizontal displacement measurement. According to the multiple moment theory, the output of these coils linearly depends to radial displacement of plasma column. A new circuit for adding these signals to feedback system designed and unwanted effects of other fields in final output compensated. After compensation and calibration of the system, the output of horizontal displacement circuits applied to feedback control system. By considers the required auxiliary vertical field, a proportional amplifier and driver circuit are constructed to drive power transistors these power transistors switch the feedback bank capacitors. In the experiment, a good linear proportionality between displacement and output observed by applying an appropriate feedback field, the linger confinement time in IR-T1 tokamak obtained, applying this system to discharge increased the plasma duration and realizes repetitive discharges

  5. Explaining the mechanisms through which regional atmospheric circulation variability drives summer temperatures and glacial melt in western High Mountain Asia (HMA)

    Science.gov (United States)

    Forsythe, Nathan; Fowler, Hayley; Blenkinsop, Stephen; Li, Xiaofeng; Pritchard, David

    2017-04-01

    Comprehension of mechanisms by which atmospheric circulation influences sub-regional temperature and water resources variability in high-elevation mountainous catchments is of great scientific urgency due to the dependency of large downstream populations on the river flows these basins provide. In this work we quantify a regional atmospheric pattern, the Karakoram Zonal Shear (KZS), with a very pronounced annual cycle which we standardise into a dimensionless (seasonal) circulation metric the Karakoram Zonal Index (KZI). Going beyond previous regional circulation metrics such as the "middle-upper tropospheric temperature index" (MUTTI) or the Webster and Yang Monsoonal Index (WYMI) which have focused solely on the South Asian Summer Monsoon (June to September) season, the KZS/KZI provides an indicator which captures the influence and interactions of the westerly jet throughout the entire annual cycle. Use of the KZS and KZI have led us to identify a further regional atmospheric system, the Karakoram Vortex, which propagates "warm high" (anticyclonic postitive temperature anomaly) and "cold low" (cyclonic negative temperature anomaly) patterns across a very broad swath of Central and South Asia in winter but over a much more constrained area of western HMA in summer. The KV exerts this temperature influence through a combination of adiabatic effects and large-scale advection. Quantify KV influence, the KZI shows strong and statistically significantly near surface (2m) air temperatures both across western HMA both as observed through local meteorological stations and as estimated by an ensemble of global meteorological reanalyses. We show that this strong influence on temperature translates to important consequences for meltwater generation from highly glaciated Indus river tributaries which is logical given that previous studies have established the role of air temperature in modulating glacially-derived river flows in western HMA. By improving the understanding of

  6. Design and experimental study of joint torque balance mechanism of seed implantation articulated robot

    Directory of Open Access Journals (Sweden)

    Zhang Yongde

    2015-06-01

    Full Text Available This article discusses several new mechanisms that may be used in prostate cancer seed implant robotics. We have developed relatively simple but effective mathematical models of multi-needle puncture prostate using nonlinear spring–damper model; based on Automatic Dynamic Analysis of Mechanical Systems or dynamics module, displacement simulation for prostate is performed, and simulation results indicate that the multi-needle puncture mechanism could reduce prostate displacement in the y- or z-direction. Then aiming at the limitation of human body structure space and seed implant needle insertion path, a revolute-revolute-translational-type prostate seed implantation robot with three-dimensional transrectal ultrasound navigation is designed. It is noteworthy that drive torque fluctuation is caused by the center of gravity change of revolute-revolute tandem cantilever structure; an elastic balance mechanism is designed to realize the complete balance of cantilever weight. Based on Automatic Dynamic Analysis of Mechanical Systems or dynamics module, static drive torque simulation of 2-revolute tandem cantilever structure is performed. Finally, we manufacture the robot prototype and make verification experiment to the cantilever balancing device, and the experiment results provide evidence that elastic balance mechanism can realize the complete balance of cantilever weight, improve the fluctuation in the amplitude value of driving torque, and increase its operation stationary of seed implantation robot system.

  7. DC drive system for cine/pulse cameras

    Science.gov (United States)

    Gerlach, R. H.; Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

    1977-01-01

    Camera-drive functions are separated mechanically into two groups which are driven by two separate dc brushless motors. First motor, a 90 deg stepper, drives rotating shutter; second electronically commutated motor drives claw and film transport. Shutter is made of one piece but has two openings for slow and fast exposures.

  8. Universal Drive Train Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This vehicle drive train research facility is capable of evaluating helicopter and ground vehicle power transmission technologies in a system level environment. The...

  9. Control rod drives

    International Nuclear Information System (INIS)

    Kimura, Koichi.

    1994-01-01

    In control rod drives, differential pressure sensors are disposed at the inlet and the exit of a driving water pressure control valve disposed in a driving water supply device and, when deviation of fluctuation of the differential pressure from a set value is detected, a pressure control valve for driving water is controlled so as to make the differential pressure constant. The differential pressure sensors detect the differential pressure between the pressure of the control rod drives at the inlet and the exit of the driving water pressure control valve and a pressure in a reactor dome. A judging circuit judges whether the differential pressure between both sides of the driving water pressure control valve is deviated from a set value or not and, if it deviates from the set value, outputs of judging signal to the control device. In the control device, the opening degree of the driving water pressure control valve is controlled, so that the differential pressure between both sides of the driving water pressure control value is constant and does not deviate from the set value. There are provided advantageous effects of preventing abnormal control rod withdrawing phenomenon to improve safety and reliability for the control of the reactor operation. (N.H.)

  10. Medications and impaired driving.

    Science.gov (United States)

    Hetland, Amanda; Carr, David B

    2014-04-01

    To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded. Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed. Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

  11. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  12. Evidences of Shear Deformations and Faulting on Comet 67P/ Churyumov-Gerasimenko: a Driving Force for the Mechanical Erosion of the Nucleus?

    Science.gov (United States)

    Matonti, C.; Auger, A. T.; Groussin, O.; Jorda, L.; Attree, N.; Viseur, S.; El Maarry, M. R.

    2016-12-01

    Fractures and faults are widespread and pervasive in Earth crustal and sedimentary rocks. They result from deviatoric stresses applied on brittle materials. In various contexts, their geometry often allows one to infer the direction and sometimes the magnitude of the stress that led to their formation. The Rosetta spacecraft has orbited comet 67P for two years and has acquired images of the nucleus surface with an unprecedented spatial resolution, down to 20 cm/px. These data open the way for entirely new geological interpretations of the structures observed at the surface of cometary nuclei. In this work, we focus on the structural interpretations of the meter to hectometer scale lineaments observed on the surface from the OSIRIS-NAC images. To improve interpretations, we performed the digitalization of lineaments in selected zones. In brittle material regions (essentially Atum and Khonsu), we observed structures that nicely match fault splay, duplexes blocks and anastomosing or "en-échelon" patterns. Such structures strongly suggest the occurrence of sheared zones and "strike-slip fault" arrays, which are observed here for the first time at the surface of a comet nucleus. Despite the large differences in the gravity magnitude and nucleus material strength compared to Earth, the observation of such structures seems to confirm comparable gravity to strength ratio between 67P and the Earth (Groussin et al., 2015). Most of these shear structures are sub-parallel and located inside or near the nucleus neck regions (Hapi, Sobek and Wosret), which is consistent with an increased relative shear stress at the boundary of the two lobes (Hirabayashi et al., 2016). These results emphasize mechanisms that may have important implications on the nucleus strength estimation and how it is eroded. Indeed, considering the fault propagation laws along with multiple angles views of structures, the observed faults likely propagate inside the nucleus over several tenths to hundreds of

  13. Colombia’s displaced indigenous women

    Directory of Open Access Journals (Sweden)

    Gina Escobar Cuero

    2017-10-01

    Full Text Available Indigenous peoples are one of the most vulnerable groups within Colombia’s internally displaced population, and a lack of understanding of their culture and needs constitutes a major challenge to their protection and assistance.

  14. Bucky gel actuator displacement: experiment and model

    International Nuclear Information System (INIS)

    Ghamsari, A K; Zegeye, E; Woldesenbet, E; Jin, Y

    2013-01-01

    Bucky gel actuator (BGA) is a dry electroactive nanocomposite which is driven with a few volts. BGA’s remarkable features make this tri-layered actuator a potential candidate for morphing applications. However, most of these applications would require a better understanding of the effective parameters that influence the BGA displacement. In this study, various sets of experiments were designed to investigate the effect of several parameters on the maximum lateral displacement of BGA. Two input parameters, voltage and frequency, and three material/design parameters, carbon nanotube type, thickness, and weight fraction of constituents were selected. A new thickness ratio term was also introduced to study the role of individual layers on BGA displacement. A model was established to predict BGA maximum displacement based on the effect of these parameters. This model showed good agreement with reported results from the literature. In addition, an important factor in the design of BGA-based devices, lifetime, was investigated. (paper)

  15. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a

  16. Epitaxial growth by monolayer restricted galvanic displacement

    Directory of Open Access Journals (Sweden)

    Vasilić Rastko

    2012-01-01

    Full Text Available The development of a new method for epitaxial growth of metals in solution by galvanic displacement of layers pre-deposited by underpotential deposition (UPD was discussed and experimentally illustrated throughout the lecture. Cyclic voltammetry (CV and scanning tunneling microscopy (STM are employed to carry out and monitor a “quasi-perfect”, two-dimensional growth of Ag on Au(111, Cu on Ag(111, and Cu on Au(111 by repetitive galvanic displacement of underpotentially deposited monolayers. A comparative study emphasizes the displacement stoichiometry as an efficient tool for thickness control during the deposition process and as a key parameter that affects the deposit morphology. The excellent quality of layers deposited by monolayer-restricted galvanic displacement is manifested by a steady UPD voltammetry and ascertained by a flat and uniform surface morphology maintained during the entire growth process.

  17. The Chinese Export Displacement Effect Revisited

    DEFF Research Database (Denmark)

    Elleby, Christian; Yu, Wusheng; Yu, Qian

    China’s global export share has increased dramatically over the past decades. This development has prompted an empirical literature on whether Chinese exports displace those originated from elsewhere in various destination markets. In this paper we focus on the growth of China’s exports to the East...... African Community (EAC) countries and show how it has affected exports from the European Union (EU) to the EAC. Our main contribution to the literature on the displacement effect of Chinese exports is a set of total and relative displacement estimates based on different specifications of the gravity model...... where we control for country-year fixed effects so as to avoid the “gold medal mistake” of not accounting for time varying “multilateral resistance”. Our findings do not support the hypothesis that Chinese exports have displaced exports from other countries in general. Nor do they support the hypothesis...

  18. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV......How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV...

  19. Fundamentals of electrical drives

    CERN Document Server

    Veltman, André; De Doncker, Rik W

    2007-01-01

    Provides a comprehensive introduction to various aspects of electrical drive systems. This volume provides a presentation of dynamic generic models that cover all major electrical machine types and modulation/control components of a drive as well as dynamic and steady state analysis of transformers and electrical machines.

  20. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  1. 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 ...

  2. Self-driving carsickness.

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and

  3. Self-driving carsickness

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and

  4. Micro-vision-based displacement measurement with high accuracy

    Science.gov (United States)

    Lu, Qinghua; Zhang, Xianmin; Fan, Yanbin

    2011-12-01

    The micro-motion stages are widely used in micro/nano manufacturing technology. In this paper, an integrated approach for measuring micro-displacement of micro-motion stage that incorporates motion estimation algorithm into the computer microvision is proposed. At first, the basic principle of the computer microvision measurement is analyzed. Then, a robust multiscale motion estimation algorithm for micro-motion measurement is proposed. Finally, the microdisplacement of the micro-motion stage based on the piezoelectric ceramic actuators and the compliant mechanisms is measured using the integrated approach. The maximal bias of the proposed approach reached 13 nm. Experimental results show that the new integrated method can measure micro-displacement with nanometer accuracy.

  5. Phenomenon of displacement in Arabic language

    Directory of Open Access Journals (Sweden)

    2015-09-01

    Full Text Available Displacement is one of the characteristics of language and common phenomena in the Arabic language. Not only is this phenomenon limited to Arabic poetry and prose, but it is also broadened, so we can see examples of this in the Qur'an. Because of this phenomenon extensively in Arabic literature and also because of its essence that leads to the transmission of the elements for the first visibility to the other visibility in the sentence and sometimes had to change the grammatical role of the words, its identify helps us in a better understanding of text and the correct translation of it and protects the reader from mistakes. This paper in the descriptive analytical approach tries studying of the phenomenon of the displacement in the Arabic language and bringing its instances in Arabic poetry and prose as well as verses contained in the Holy Quran, to show that through the types and characteristics in the Arabic language and to response to several questions, including: how important is the displacement and what is its types in rhetoric, and the reasons of the displacement, and etc... Of the most important results of this study may refer to the undeniable role of the displacement as a rhetorical method to better understanding of the texts including: one of the most important reasons of the displacement in the use of language is to improve speech verbally and morally, and violation of the standard language and create a poetic atmosphere, and the recognition of the occurrence of the phenomenon of displacement in the Arabic language that uphold different interpretations remote and estimates when faced with the displacement in the text and help us to understand it and etc...

  6. Histone displacement during nucleotide excision repair

    DEFF Research Database (Denmark)

    Dinant, C.; Bartek, J.; Bekker-Jensen, S.

    2012-01-01

    , thus allowing repair proteins to efficiently access DNA. On the other hand, after completion of the repair, the chromatin must be returned to its previous undamaged state. Chromatin remodeling can refer to three separate but interconnected processes, histone post-translational modifications, insertion...... of histone variants and histone displacement (including nucleosome sliding). Here we review current knowledge, and speculate about current unknowns, regarding those chromatin remodeling activities that physically displace histones before, during and after NER....

  7. 2014 and beyond: implications for displacement

    Directory of Open Access Journals (Sweden)

    Aidan O’Leary

    2014-05-01

    Full Text Available 2014 marks a watershed for Afghanistan, with the withdrawal of the International Security Assistance Force after twelve years, and the very real risks this withdrawal poses to the capacity of the Afghan state to meet the many internal and external challenges faced by the country. These challenges have significant implications for displaced and returning Afghans and for the potential for displacement in the future.

  8. Control rod drives

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1984-01-01

    Purpose: To enable to monitor the coupling state between a control rod and a control rod drive. Constitution: After the completion of a control rod withdrawal, a coolant pressure is applied to a control rod drive being adjusted so as to raise only the control rod drive and, in a case where the coupling between the control rod drive and the control rod is detached, the former is elevated till it contacts the control rod and then stopped. The actual stopping position is detected by an actual position detection circuit and compared with a predetermined position stored in a predetermined position detection circuit. If both of the positions are not aligned with each other, it is judged by a judging circuit that the control rod and the control rod drives are not combined. (Sekiya, K.)

  9. The driving force for magnetospheric convection

    Science.gov (United States)

    Johnson, F. S.

    1978-01-01

    Viscously driven magnetospheric models, as well as a model involving interconnection between the geomagnetic field and the magnetic field in the solar wind, have been proposed to describe the driving force for magnetospheric convection. Lack of a satisfactory theory for the interconnection in the latter model and, in the case of the viscous interaction models, inadequacies in predicting the quantity of the driving force, make these two classes of models less than successful. Accordingly, a mechanically driven magnetospheric model is proposed: solar wind plasma enters the magnetosphere around the neutral points, covers the inner surface of the magnetopause and subsequently expands, driving convection as it escapes from the open tail.

  10. Snubber assembly for a control rod drive

    International Nuclear Information System (INIS)

    Matthews, J.C.

    1978-01-01

    A snubber cartridge assembly is mounted to the nozzle of a control rod drive mechanism to insure that the snubber assembly will be located within the liquid filled section of a nuclear reactor vessel whenever the control rod drive is assembled thereto. The snubber assembly includes a piston mounted proximate to the control rod connecting end of the control rod drive leadscrew to allow the piston to travel within the liquid filled snubber cartridge and controllably exhaust liquid therefrom during a ''scram'' condition. The snubber cartridge provides three separate areas of increasing resistance to piston travel to insure a speedy but safe ''scram'' of the control rod into the reactor

  11. Strain-independent fiber torsion and displacement sensor based on acoustically-induced fiber grating

    Science.gov (United States)

    Liu, Yu; Ren, Guobin; Jiang, Youchao; Mi, Yuean; Li, Haisu; Zhu, Bofeng; Yang, Yuguang; Shen, Ya; Jian, Shuisheng

    2018-02-01

    We present a strain-independent torsion and displacement fiber sensor using acoustically-induced fiber grating (AIFG) in dual-mode fiber (DMF). By tuning the radio frequency of driving signal, LP01 and LP11 modes generated by the AIFG can be exploited to measure the dynamic displacement and torsion variations, respectively. Both the twist angle and the twist direction can be monitored via image detection facility at the end of DMF. Between torsion angles of -80° and 80°, the highest twist sensitivity reaches 15 pixel/°. The average displacement sensitivity is 5 pixel/μm within the recorded two-dimensional movement of 100um × 80um. The stable property of sensor is verified when the strain is varied from 100 με to 1500 με.

  12. SOCIAL CAPITAL IN INVOLUNTARY DISPLACEMENT AND RESETTLEMENT

    Directory of Open Access Journals (Sweden)

    Melissa Quetulio-Navarra

    2013-07-01

    Full Text Available Social capital is often seen as a substitute for lack of other types of capital amongpoor people. Because of the recognized applicability of the social capital conceptand its correlation with the different dimensions of poverty, it has been used inevaluating the adaptation and integration of involuntarily displaced individualsinto their new environment. This paper presents insights based on a review of thefindings of studies that looked into the role of social capital in conflict- anddevelopment-induced displacement contexts. Althoughboth types of displace-ments are involuntary or forced in nature, they differ in terms of the role of socialcapital regarding its main sources, the formation pattern and its determinants.Social capital studies in forced resettlement appear to be relatively small innumber and are heavily concentrated on first worldcountries and conflict- anddevelopment-induced displacements. The conduct of similar studies in developingcountries and in a disaster-induced resettlement context, the third type ofinvoluntary displacement, should generate new and relevant findings regardingthe role of social capital in resettlement communities.

  13. Granular gases under extreme driving

    Science.gov (United States)

    Kang, W.; Machta, J.; Ben-Naim, E.

    2010-08-01

    We study inelastic gases in two dimensions using event-driven molecular-dynamics simulations. Our focus is the nature of the stationary state attained by rare injection of large amounts of energy to balance the dissipation due to collisions. We find that under such extreme driving, with the injection rate much smaller than the collision rate, the velocity distribution has a power-law high-energy tail. The numerically measured exponent characterizing this tail is in excellent agreement with predictions of kinetic theory over a wide range of system parameters. We conclude that driving by rare but powerful energy injection leads to a well-mixed gas and constitutes an alternative mechanism for agitating granular matter. In this distinct nonequilibrium steady state, energy cascades from large to small scales. Our simulations also show that when the injection rate is comparable with the collision rate, the velocity distribution has a stretched exponential tail.

  14. Reasonable Width of Narrow Coal Pillar of Gob-side Entry Driving in Large Mining Height

    Science.gov (United States)

    Ming, Zhao; Shuai, Zhang; Yong, Chen

    2017-03-01

    To determine the reasonable width of the gob-side entry driving coal pillar in Xieqiao Mine, firstly, the theoretical analysis method was applied to construct the mechanical model for limit equilibrium area of coal seam edge, and the distance obtained via analysis between the bearing pressure extremum and the coal edge was 3.34 m. Secondly, the numerical simulation method was applied to analyze the roadway rock mechanics with different coal pillar widths, and it is concluded that the width of the coal pillar was staying in a chaos area which was not conducive to the stability of the system when the peak stress position of the roof changed suddenly and the reasonable width was determined at 5 m. Finally, the high-strength, high pre-stressed bolt and cable anchor supporting test was carried out in the roadway, with 60 mm of roof subsidence, 207 mm of two sides displacement, 305 mm of floor heave, 135 mm of lateral displacement of coal pillar, 7 d duration of strong roadway rock deformation in pressure, in which the deformation meet the safety production of mine and increased the technical and economic benefit remarkably.

  15. Static and Dynamic Experiment Evaluations of a Displacement Differential Self-Induced Magnetorheological Damper

    Directory of Open Access Journals (Sweden)

    Guoliang Hu

    2015-01-01

    Full Text Available This paper presents the development of a novel magnetorheological damper (MRD which has a self-induced ability. In this study, a linear variable differential sensor (LVDS based on the electromagnetic induction mechanism was integrated with a conventional MRD. The structure of the displacement differential self-induced magnetorheological damper (DDSMRD was developed, and the theory of displacement differential self-induced performance was deduced. The static experiments of the DDSMRD under different displacement positions were carried out by applying sine excitation signals to the excitation coils, and the experimental results show that the self-induced voltage is proportional to the damper piston displacement. Meanwhile, the dynamic experiments were also carried out using the fatigue test machine to investigate the change of the self-induced voltage under the typical direct current inputs and the different piston rod displacements; the experimental results also show that the self-induced voltage is proportional to the damper piston displacements. Additionally, the dynamic mechanical performance of the DDSMRD was evaluated. The theory deduction and the experimental results indicate that the proposed DDSMRD has the ability of the integrated displacement sensor in addition to the output controllable damping force.

  16. Fiber-optic displacement sensors on the Hunters Trophy UGT impulse gauge experiments

    Energy Technology Data Exchange (ETDEWEB)

    Green, R.E.L.; Poutiatine, A.I.

    1995-03-01

    As part of a program to develop gauges for measurement of various mechanical properties in hostile environments, the authors fielded purely optical displacement sensors at the ends of long fiber-optic cables as supplements to the regular displacement sensors of four impulse gauges fielded as part of a materials study on the Hunters Trophy underground effects test at the Nevada Test Site. These fiber-optic sensor systems and their performance on the Hunters Trophy test are described in this report.

  17. Identifying Method of Drunk Driving Based on Driving Behavior

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhao

    2011-05-01

    Full Text Available Drunk driving is one of the leading causes contributing to traffic crashes. There are numerous issues that need to be resolved with the current method of identifying drunk driving. Driving behavior, with the characteristic of real-time, was extensively researched to identify impaired driving behaviors. In this paper, the drives with BACs above 0.05% were defined as drunk driving state. A detailed comparison was made between normal driving and drunk driving. The experiment in driving simulator was designed to collect the driving performance data of the groups. According to the characteristics analysis for the effect of alcohol on driving performance, seven significant indicators were extracted and the drunk driving was identified by the Fisher Discriminant Method. The discriminant function demonstrated a high accuracy of classification. The optimal critical score to differentiate normal from drinking state was found to be 0. The evaluation result verifies the accuracy of classification method.

  18. Modeling and Positioning of a PZT Precision Drive System.

    Science.gov (United States)

    Liu, Che; Guo, Yanling

    2017-11-08

    The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied.

  19. Modeling and Positioning of a PZT Precision Drive System

    Directory of Open Access Journals (Sweden)

    Che Liu

    2017-11-01

    Full Text Available The fact that piezoelectric ceramic transducer (PZT precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied.

  20. Synthesis of mechanisms with prescribed elastic load-displacement characteristics

    NARCIS (Netherlands)

    Radaelli, G.

    2017-01-01

    In this dissertation a collection of concepts to synthesise nonlinear springs is presented. Such springs can be useful in various application domains where, e.g., multi-stability or static balancing is desired. These behaviors are often sought to alleviate the effort required for actuation. The

  1. Electromagnetic drive of the control and protection system of a nuclear reactor

    International Nuclear Information System (INIS)

    Zav'yalova, G.I.

    1983-01-01

    The design and operating principle of an electromagnetic drive with a linear synchronous reaction motor are described. At the present time, electromagnetic control mechanisms using linear electric motors are finding increasingly widespread application as drives for the control and protection system of nuclear reactors. In these drives there is a functional mergence of the electromagnetic mechanism with the final control element; these drives, therefore, have advantages over electromechanical drives

  2. Tractor Mechanics. Maintaining and Servicing the Power Train, Learning Activity Packages 49-53; Maintaining and Servicing the Clutch, Learning Activity Packages 54-59; Maintaining and Servicing the Transmission and Differential, Learning Activity Packages 60-68; Maintaining and Servicing the Final Drive, Learning Activity Packages 69-77.

    Science.gov (United States)

    Clemson Univ., SC. Vocational Education Media Center.

    This series of learning activity packages focuses on four areas of tractor mechanics: (1) maintaining and servicing the power train, (2) maintaining and servicing the clutch, (3) maintaining and servicing the transmission and differential, and (4) maintaining and servicing the final drive. Each of the twenty-nine illustrated learning activity…

  3. Uncovering deformation processes from surface displacements

    Science.gov (United States)

    Stramondo, Salvatore

    2013-04-01

    The aim of this talk is to provide an overview about the most recent outcomes in Earth Sciences, describe the role of satellite remote sensing, together with GPS, ground measurement and further data, for geophysical parameter retrieval in well known case studies where the combined approach dealing with the use of two or more techniques/datasets have demonstrated their effectiveness. The Earth Sciences have today a wide availability of instruments and sensors able to provide scientists with an unprecedented capability to study the physical processes driving earthquakes, volcanic eruptions, landslides, and other dynamic Earth systems. Indeed measurements from satellites allow systematic observation of the Earth surface covering large areas, over a long time period and characterized by growing sample intervals. Interferometric Synthetic Aperture Radar (InSAR) technique has demonstrated its effectiveness to investigate processes responsible for crustal faulting stemming from the detection of surface deformation patterns. Indeed using satellite data along ascending and descending orbits, as well as different incident angles, it is possible in principle to retrieve the full 3D character of the ground motion. To such aim the use of GPS stations providing 3D displacement components is a reliable complementary instrument. Finally, offset tracking techniques and Multiple Aperture Interferometry (MAI) may provide a contribution to the analysis of horizontal and NS deformation vectors. The estimation of geophysical parameters using InSAR has been widely discussed in seismology and volcanology, and also applied to deformation associated with groundwater and other subsurface fluids. These applications often involve the solution of an inverse problem, which means the retrieval of optimal source parameters at depth for volcanoes and earthquakes, from the knowledge of surface deformation from InSAR. In recent years, InSAR measurements combined with traditional seismological and

  4. High-displacement spiral piezoelectric actuators

    Science.gov (United States)

    Mohammadi, F.; Kholkin, A. L.; Jadidian, B.; Safari, A.

    1999-10-01

    A high-displacement piezoelectric actuator, employing spiral geometry of a curved piezoelectric strip is described. The monolithic actuators are fabricated using a layered manufacturing technique, fused deposition of ceramics, which is capable of prototyping electroceramic components with complex shapes. The spiral actuators (2-3 cm in diameter) consisted of 4-5 turns of a lead zirconate titanate ceramic strip with an effective length up to 28 cm. The width was varied from 0.9 to 1.75 mm with a height of 3 mm. When driven by the electric field applied across the width of the spiral wall, the tip of the actuator was found to displace in both radial and tangential directions. The tangential displacement of the tip was about 210 μm under the field of 5 kV/cm. Both the displacement and resonant frequency of the spirals could be tailored by changing the effective length and wall width. The blocking force of the actuator in tangential direction was about 1 N under the field of 5 kV/cm. These properties are advantageous for high-displacement low-force applications where bimorph or monomorph actuators are currently employed.

  5. Drugs and driving

    NARCIS (Netherlands)

    Walsh, J. Michael; De Gier, Johan J.; Christopherson, Asbjørg S.; Verstraete, Alain G.

    The authors present a global overview on the issue of drugs and driving covering four major areas: (1) Epidemiology and Prevalence-which reviews epidemiological research, summarizes available information, discusses the methodological shortcomings of extant studies, and makes recommendations for

  6. Science of driving.

    Science.gov (United States)

    2016-08-01

    The Science of Driving project focused on developing a collaborative relationship to develop curriculum units for middle school and high school students to engage them in exciting real-world scenarios. This effort involved faculty, staff, and student...

  7. Compliant displacement-multiplying apparatus for microelectromechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Kota, Sridhar (9391 Quail Ridge Run, Brighton, MI 48114); Rodgers, M. Steven (12216 Papaya Ct., NE., Albuquerque, NM 87111); Hetrick, Joel A. (818 S. Gammon, Apartment 4, Madison, WI 53719)

    2001-01-01

    A pivotless compliant structure is disclosed that can be used to increase the geometric advantage or mechanical advantage of a microelectromechanical (MEM) actuator such as an electrostatic comb actuator, a capacitive-plate electrostatic actuator, or a thermal actuator. The compliant structure, based on a combination of interconnected flexible beams and cross-beams formed of one or more layers of polysilicon or silicon nitride, can provide a geometric advantage of from about 5:1 to about 60:1 to multiply a 0.25-3 .mu.m displacement provided by a short-stroke actuator so that such an actuator can be used to generate a displacement stroke of about 10-34 .mu.m to operate a ratchet-driven MEM device or a microengine. The compliant structure has less play than conventional displacement-multiplying devices based on lever arms and pivoting joints, and is expected to be more reliable than such devices. The compliant structure and an associated electrostatic or thermal actuator can be formed on a common substrate (e.g. silicon) using surface micromachining.

  8. A mathematical model of the shore level displacement in Fennoscandia

    International Nuclear Information System (INIS)

    Paasse, T.

    1996-12-01

    The shore level displacement in Fennoscandia (Scandinavia and Finland) is mainly due to two cooperative vertical movements, the glacio-isostatic uplift and the eustatic sea level rise. The course of the glacio-isostatic uplift has recently been made discernible according to an investigation of the lake tilting phenomenon. This new information has made it possible to start an iteration process for detailed estimations of the uplift and the rise using empirical data of the shore level displacement. Arctan-functions have proved to be suitable tools for describing the glacio-isostatic uplift. The model indicates that there are two mechanisms involved in the glacio-isostatic uplift, one slow that can be linked to viscous flow, and one fast that might be explained by compression followed by decompression. The future development regarding the glacio-isostatic uplift, the eustasy and the shore level displacement is predicted in Fennoscandia using the results from the modeling. The predictions are based on the assumption that the crustal and eustatic developments will follow the trends that exist today. 124 refs, 98 figs

  9. Analysis of a novel double driving signal line and driving electrodes separated RF MEMS switch

    Science.gov (United States)

    Chen, Zhiqiang; Tian, Wenchao; Zhang, Xiaotong

    2017-04-01

    A novel double driving signal line and driving electrodes separated radio frequency (RF) micro-electromechanical system (MEMS) switch was proposed in this paper to overcome the problems of the high actuation voltage, small displacement, and long pull-down time of the RF MEMS switches. Dynamic equations of the micro beam were built based on the small deflection theory. Dynamic behaviors of the proposed RF MEMS switch were analyzed and calculated by the variable separation method. The effects of different driving voltages, structure parameters and materials on the RF MEMS switch performance were discussed in detail. The simulation results presented that the proposed RF MEMS switch had an actuation voltage of 26 V, a pull-down time of 31.5 μs and an actuation displacement of 3 μm. The results also showed that the pull-down time of micro beam increased as the dielectric layer thickness increased. When the beam thickness was higher than 1.1 μm, the switch could not pull down anymore. Additionally, the switch had a lowest pull down time when Al was used as micro beam material, compared to Au, Si, and SiC. The COMSOL Multiphysics finite element analysis was carried out to validate the MATLAB simulation results, and the comparison results were basically consistent with the MATLAB simulation results. Besides, the proposed switch had an insertion loss of -0.2 dB on up-state and isolation of more than -20 dB on down-state at 60 GHz derived from the electromagnetic simulation results. The actuation voltage, pull-down time, actuation displacement, and electromagnetic performances of the proposed RF MEMS switch were compared to some other switches, which were better than some existing switches.

  10. Instant Google Drive starter

    CERN Document Server

    Procopio, Mike

    2013-01-01

    This book is a Starter which teaches you how to use Google Drive practically. This book is perfect for people of all skill levels who want to enjoy the benefits of using Google Drive to safely store their files online and in the cloud. It's also great for anyone looking to learn more about cloud computing in general. Readers are expected to have an Internet connection and basic knowledge of using the internet.

  11. Belt drive construction improvement

    Directory of Open Access Journals (Sweden)

    I.Yu. Khomenko

    2012-08-01

    Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

  12. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  13. Epilepsy and driving

    Directory of Open Access Journals (Sweden)

    Moetamedi M

    2000-09-01

    Full Text Available Epilepsy is a disease with high prevalence, which interferes driving and may lead to car accident; This case-control study has been done on 100 epileptic patients and 100 persons as control group, who had history of driving. We gathered our patients with face to face interview and registering their information in special forms which were prepared for this study. There were three times more accidents among epileptic cases comparing with control group and this difference was more considerable in men and in patients under 35 years old. The cause of accident were not seizure attack in more than 60% of the patients and these ordinary accidents were also more in case group. Epileptic patients with history of car accidents during driving had poor drug compliance comparing with the epileptics without history of an accident so drug compliance may be valuable in predicting accident in these patients. We have also found poor drug compliance in whom seizure attacks caused accident for them. 58% of the epileptics had not consulted their physician about driving. 43.3% of seizures during driving were of generalized type and none of the patients had inform police about their disease during getting driving license.

  14. Dementia and driving.

    Science.gov (United States)

    O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K

    1992-04-01

    Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the driving practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to drive after the onset of dementia, and impaired driving ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop driving, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to driving ability. These findings suggest that many patients with dementia drive in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed.

  15. TREATMENT OPTIONS FOR DISPLACED FRACTURE OF THE CALCANEAL TUBEROSITY

    Directory of Open Access Journals (Sweden)

    Siva G. Prasad

    2016-12-01

    Full Text Available BACKGROUND The aim of the study is to compare the outcome following conservative or surgical treatment for displaced fracture of the medial process of the calcaneal tuberosity. MATERIALS AND METHODS 14 men and 4 women aged 20 to 44 years chose to undergo conservative (9 feet or surgical (10 feet treatment by a single surgeon for closed displaced fracture of the medial process of the calcaneal tuberosity. The injury mechanism was a fall from a height of <1.5 m; the mean time from injury to treatment was 3 (range 1-7 days. Conservative treatment comprised immobilisation in a plaster cast. Surgical treatment involved fixation with a half thread cannulated screw for large fragments (in 6 feet or a mini-plate for comminuted fragments (in 4 feet. At the final follow-up, the American Orthopaedic Foot and Ankle Society (AOFAS ankle and hind foot score was evaluated. RESULTS The conservative and surgery groups were comparable in terms of age, gender and fracture displacement. The mean follow-up duration was 20 (range, 14-24 months. All patients had bone union; none had implant loosening or breakage. One patient with surgical treatment developed skin numbness at the medial aspect of the heel that resolved following neurotrophic drug treatment for 3 months. The surgery group achieved earlier full weight bearing (5.8 vs. 7.5 weeks, p<0.001 and return to work (5.9 vs. 8.2 weeks, p=0.048, but comparable AOFAS score (89.0 vs. 88.2, p=0.4. CONCLUSION Surgery for displaced fracture of the medial process of the calcaneal tuberosity enabled earlier full weight bearing and return to work, but comparable AOFAS score.

  16. Performance of displacement ventilation in practice

    DEFF Research Database (Denmark)

    Naidenov, K.; Pitchurov, G.; Langkilde, Gunnar

    2002-01-01

    This paper presents results of a field study in offices with displacement ventilation. It comprises detailed physical measurements of the thermal environment and collection of occupants´ response at 227 workplaces. The results, both physical measurements and human response, identified draught as ...... ventilation principle. This will ensure proper and efficient operation of the system and occupants´ satisfaction.......This paper presents results of a field study in offices with displacement ventilation. It comprises detailed physical measurements of the thermal environment and collection of occupants´ response at 227 workplaces. The results, both physical measurements and human response, identified draught...... as the major local discomfort in the rooms with displacement ventilation. Twenty-three percent of the occupants were daily bothered by draught. In some buildings the maintenance personnel tried to improve occupants´ thermal comfort by raising the supply air temperature or office workers themselves blocked...

  17. Forced displacement and women's security in Colombia.

    Science.gov (United States)

    Meertens, Donny

    2010-04-01

    In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes.

  18. Overtreatment of displaced midshaft clavicle fractures

    DEFF Research Database (Denmark)

    Ban, Ilija; Nowak, Jan; Virtanen, Kaisa

    2016-01-01

    Background and purpose - The best treatment for displaced clavicle fractures has been debated for decades. Operative treatment has become more common. However, several randomized trials comparing non-operative and operative treatment have not shown any compelling evidence in favor of surgery. We...... identified the preferred treatment of displaced midshaft clavicle fractures at public hospitals in 3 countries in Scandinavia. Patients and methods - A purpose-made multiple-choice questionnaire in English was sent to all public hospitals in Denmark, Sweden, and Finland. This was addressed to the orthopedic...... surgeon responsible for treatment of clavicle fractures, and completed questionnaires were obtained from 85 of 118 hospitals. Results - In the 3 countries, 69 of the 85 hospitals that responded would treat displaced clavicle fractures operatively. Clear criteria for treatment allocation were used at 58...

  19. Sensing Property Modeling for the Novel Horizontal-vertical Composite Underground Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Nanying Shentu

    2014-08-01

    Full Text Available Due to invisibility and complexity of the underground displacement monitoring, there exit few practical monitoring sensors capable of monitoring the underground horizontal and vertical displacements simultaneously. A novel electromagnetic underground displacement sensor able to monitor both the horizontal and the vertical displacements was proposed in our previous studies and abbreviated as the H-V type sensor. Through comprehensive application of Hall sensing mechanism analysis, 3D magnetic field distribution solution to the permanent magnet, and multidimensional numerical integration method, a model called the Equivalent Magnetic Charge-Numerical Integration Model (EMC-NI is presented in this paper and serves as the H-V type sensor’s Hall voltage measurement model. This model can quantitatively evaluate the complicated relationship among the sensor’s Hall voltage output, its measuring parameters (underground horizontal displacement, vertical displacement and tilt angle at different depth within the monitored soil rock mass and morphological parameters (geometry, shape and property parameters for the sensor units. Comprehensive studies and comparisons have conducted between the experimentally measured and EMC-NI modeled Hall voltage under counterpart conditions, through which not only the model’s modeling effectiveness and calculation accuracy are objectively evaluated, but also some valuable theoretical support is provided for the sensor’ sensing properties evaluation, design optimization, and subsequent study of displacement parameter inversion approach.

  20. Kinematics and Dynamics of Roller Chain Drives

    DEFF Research Database (Denmark)

    Fuglede, Niels

    There are two main subjects of this work: Kinematic and dynamic modeling and analysis of roller chain drives. In the kinematic analysis we contribute first with a complete treatment of the roller chain drive modeled as a four-bar mechanism. This includes a general, exact and approximate analysis...... which is useful for predicting the characteristic loading of the roller chain drive. As a completely novel contribution, a kinematic model and analysis is presented which includes both spans and sprockets in a simple chain drive system. A general procedure for determination of the total wrapping length...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain...

  1. Maxillary tooth displacement in the infratemporal fossa

    Directory of Open Access Journals (Sweden)

    Korosh Roshanghias

    2016-01-01

    Full Text Available Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa.

  2. DNA fork displacement rates in human cells

    International Nuclear Information System (INIS)

    Kapp, L.N.; Painter, R.B.

    1981-01-01

    DNA fork displacement rates were measured in 20 human cell lines by a bromodeoxyuridine-313 nm photolysis technique. Cell lines included representatives of normal diploid, Fanconi's anemia, ataxia telangiectasia, xeroderma pigmentosum, trisomy-21 and several transformed lines. The average value for all the cell lines was 0.53 +- 0.08 μm/min. The average value for individual cell lines, however, displayed a 30% variation. Less than 10% of variation in the fork displacement rate appears to be due to the experimental technique; the remainder is probably due to true variation among the cell types and to culture conditions. (Auth.)

  3. Bucket Foundation Response Under Various Displacement Rates

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2016-01-01

    The present testing program aims at showing the pore pressure response around a bucket foundation skirt as well as the load and displacement change due to ten different displacement rates. Research findings are useful for a numerical model calibration focusing on the design of the upwind foundation...... in a multi-bucket foundation system. The foundation model is at a scale of approximately 1:20 prototype foundation size. The tests are performed in a pressure tank with the foundation model installed in dense sand. Based on the data, the conclusion is that the bucket foundation design in a storm case should...

  4. Passive Smoking in a Displacement Ventilated Room

    DEFF Research Database (Denmark)

    Bjørn, Erik; Nielsen, Peter V.

    The aim of this research is to see if the displacement ventilation principle can protect a person from exposure to passive tobacco smoking. This is done by full-scale experiments with two breathing thermal manikins, smoke visualisations, and tracer gas measurements. In some situations, exhaled...... smoke will stratify in a certain height due to the vertical temperature gradient. This horizontal layer of exhaled tobacco smoke may lead to exposure. In other situations, the smoke is mixed into the upper zone, and the passive smoker is protected to some extent by the displacement principle...

  5. Investigation of New Servo Drive Concept Utilizing Two Fixed Displacement Units

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Schmidt, Lasse; Andersen, Torben Ole

    2014-01-01

    first presents an analysis of the general concept, showing that both cavitation and excessive pressure build up needs to be handled by the system, after which the system is presented and modelled. Finally both simulation and experimental results are presented showing the validity of the concept....... most solutions that have tried to overcome this problem have incorporated some kind of accumulator. In the present paper a new concept is presented, modelled and analyzed, and it is shown that the concept overcomes the problem with asymmetric cylinders, without the use of an accumulator. The paper...

  6. Control of a 420 KN Discrete Displacement Cylinder Drive for the Wavestar Wave Energy Converter

    DEFF Research Database (Denmark)

    Hansen, Rico H.; Andersen, Torben Ole; Pedersen, Henrik C.

    2014-01-01

    To improve the power production of their 1 MW wave energy converter, Wavestar is developing a new transmission based on discrete hydraulics. The discrete hydraulic system allows all cylinders to supply a common accumulator storage while maintaining low-loss individual force control of the 20...... different area/pressure combinations. Currently, a 420 kN DDC prototype has been implemented and tested at the newly commissioned full size wave energy testbench at Aalborg University. The initial design and control of the DDC had poorly damped switching transients. These issues treated in this paper...

  7. Experiments and simulation of thermal behaviors of the dual-drive servo feed system

    Science.gov (United States)

    Yang, Jun; Mei, Xuesong; Feng, Bin; Zhao, Liang; Ma, Chi; Shi, Hu

    2015-01-01

    The machine tool equipped with the dual-drive servo feed system could realize high feed speed as well as sharp precision. Currently, there is no report about the thermal behaviors of the dual-drive machine, and the current research of the thermal characteristics of machines mainly focuses on steady simulation. To explore the influence of thermal characterizations on the precision of a jib boring machine assembled dual-drive feed system, the thermal equilibrium tests and the research on thermal-mechanical transient behaviors are carried out. A laser interferometer, infrared thermography and a temperature-displacement acquisition system are applied to measure the temperature distribution and thermal deformation at different feed speeds. Subsequently, the finite element method (FEM) is used to analyze the transient thermal behaviors of the boring machine. The complex boundary conditions, such as heat sources and convective heat transfer coefficient, are calculated. Finally, transient variances in temperatures and deformations are compared with the measured values, and the errors between the measurement and the simulation of the temperature and the thermal error are 2 °C and 2.5 μm, respectively. The researching results demonstrate that the FEM model can predict the thermal error and temperature distribution very well under specified operating condition. Moreover, the uneven temperature gradient is due to the asynchronous dual-drive structure that results in thermal deformation. Additionally, the positioning accuracy decreases as the measured point became further away from the motor, and the thermal error and equilibrium period both increase with feed speeds. The research proposes a systematical method to measure and simulate the boring machine transient thermal behaviors.

  8. Displaced Medial and Lateral Bucket Handle Meniscal Tears With Intact ACL and PCL.

    Science.gov (United States)

    Boody, Barrett S; Omar, Imran M; Hill, James A

    2015-08-01

    Bucket handle lesions are vertical longitudinal tears in the meniscus that may displace centrally into the respective medial or lateral compartment, frequently causing mechanical symptoms, including pain, perceived instability, and mechanical locking. Bucket handle meniscal tears are most commonly from a traumatic etiology and are frequently found with concomitant anterior cruciate ligament (ACL) injuries. Multiple imaging signs and associations have been described for the diagnosis of bucket handle meniscus tears, including coronal truncation, absent bow tie sign, double posterior cruciate ligament (PCL), double ACL, displacement of the bucket handle fragment, and disproportionate posterior horn signs. Among meniscal pathology encountered on magnetic resonance imaging or during arthroscopy, bucket handle meniscal tears are infrequent occurrences. Furthermore, the occurrence of displaced medial and lateral bucket handle tears found on imaging and during arthroscopy is very uncommon and is only sparsely reported in the literature. When displaced medial and lateral bucket handle meniscal segments are visualized within the intercondylar notch along with the ACL and PCL, the radiologic findings are referred to as the "quadruple cruciate" sign or the "Jack and Jill lesion." Of the few case reports described in the literature, only one noted displaced medial and lateral bucket handle meniscus tears with an intact ACL and PCL. The current case report outlines a similar rare case of the quadruple cruciate sign: displaced medial and lateral bucket handle meniscal tears located within the intercondylar notch and an intact ACL and PCL. Copyright 2015, SLACK Incorporated.

  9. Design of a Novel Electro-hydraulic Drive Downhole Tractor

    Science.gov (United States)

    Fang, Delei; Shang, Jianzhong; Yang, Junhong; Wang, Zhuo; Wu, Wei

    2018-02-01

    In order to improve the traction ability and the work efficiency of downhole tractor in oil field, a novel electro-hydraulic drive downhole tractor was designed. The tractor’s supporting mechanism and moving mechanism were analyzed based on the tractor mechanical structure. Through the introduction of hydraulic system, the hydraulic drive mechanism and the implementation process were researched. Based on software, analysis of tractor hydraulic drive characteristic and movement performance were simulated, which provide theoretical basis for the development of tractor prototype.

  10. Control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Hiroyasu.

    1979-01-01

    Purpose: To enable rapid control in a simple circuit by providing a motor control device having an electric capacity capable of simultaneously driving all of the control rods rapidly only in the inserting direction as well as a motor controlling device capable of fine control for the insertion and extraction at usual operation. Constitution: The control rod drives comprise a first motor control device capable of finely controlling the control rods both in inserting and extracting directions, a second motor control device capable of rapidly driving the control rods only in the inserting direction, and a first motor switching circuit and a second motor switching circuit switched by switches. Upon issue of a rapid insertion instruction for the control rods, the second motor switching circuit is closed by the switch and the second motor control circuit and driving motors are connected. Thus, each of the control rod driving motors is driven at a high speed in the inserting direction to rapidly insert all of the control rods. (Yoshino, Y.)

  11. Nocturnal Valley Cold Air Pool Displacement on a Desert Mountain Slope

    Science.gov (United States)

    Jeglum, M. E.; Hoch, S.

    2015-12-01

    The Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program collected a high-resolution observational dataset to test and improve mesoscale model performance and weather prediction in complex terrain. One of the focal points of the MATERHORN field program was a relatively uniform mountain slope where large nocturnal temperature variations due to the displacement of a valley cold air pool (CAP) up the slope have been observed. CAP displacements can significantly impact the near-surface temperature and wind but are poorly represented in mesoscale models. This work aims to identify the spatial and temporal distribution of CAP displacements and the mechanisms causing them. CAP displacements are identified using data from a transect of 4 automatic weather stations (AWS) and 5 flux towers deployed on the east slope of Granite Peak (GP) in Northwest Utah. The instrument transect spans 130 m of elevation starting on the valley floor and rising up the uniform alluvial fan at the base of GP. 116 additional AWS's in the vicinity of GP are used to diagnose the mechanisms causing the displacements. The dense grid of observations allows the tracking of coherent features in the pressure, temperature, and wind fields as they interact with the CAP and the topography of GP. Two time periods, October 2012 and May 2013, were investigated for the presence of CAP displacements and their causes. In October, a typical night exhibits an average of 5 cold-pool displacement events that are evenly distributed between 2100 and 0500 MST when valley CAPs have developed. In May, fewer displacement events are observed (3 per night) and they occur preferentially later in the night, between 0000 and 0400 MST. Displacements are frequently associated with features that can be tracked across the plain surrounding GP. These features include slope and valley flow "fronts" descending the surrounding terrain, seiching, and mesoscale boundaries. In addition to describing the spatial and

  12. Displacement Forecasting Method in Brittle Crack Surrounding Rock Under Excavation Unloading Incorporating Opening Deformation

    Science.gov (United States)

    Li, X. J.; Yang, W. M.; Wang, L. G.; Butler, I. B.

    2014-11-01

    Splitting failure, which is recognized as a special engineering geology phenomenon, occurs continually in the brittle rock mass of caverns during underground excavation. In this paper, a splitting model of linear slippage crack groups is built with fracture mechanics, energy analysis, and crack extension theories. Considering intrinsic cracks in rock mass and change of outer stress, intrinsic cracks propagate into macroscopical splitting cracks that are approximately parallel to the side wall of caverns. The splitting criterion of cavern rock mass and the method for predicting displacement in view of splitting opening displacement are proposed. In the end, the forecasting method is applied to the Jinping-I Hydropower Station, underground caverns engineering in China, the splitting failure zone and forecasting displacement are accordant with the monitoring data. The new forecasting displacement method is proven to contribute to the construction of similar underground caverns.

  13. Spring constant measurement using a MEMS force and displacement sensor utilizing paralleled piezoresistive cantilevers

    Science.gov (United States)

    Kohyama, Sumihiro; Takahashi, Hidetoshi; Yoshida, Satoru; Onoe, Hiroaki; Hirayama-Shoji, Kayoko; Tsukagoshi, Takuya; Takahata, Tomoyuki; Shimoyama, Isao

    2018-04-01

    This paper reports on a method to measure a spring constant on site using a micro electro mechanical systems (MEMS) force and displacement sensor. The proposed sensor consists of a force-sensing cantilever and a displacement-sensing cantilever. Each cantilever is composed of two beams with a piezoresistor on the sidewall for measuring the in-plane lateral directional force and displacement. The force resolution and displacement resolution of the fabricated sensor were less than 0.8 µN and 0.1 µm, respectively. We measured the spring constants of two types of hydrogel microparticles to demonstrate the effectiveness of the proposed sensor, with values of approximately 4.3 N m-1 and 15.1 N m-1 obtained. The results indicated that the proposed sensor is effective for on-site spring constant measurement.

  14. Onset of Dynamic Wetting Failure: The Influence of the Displaced Fluid

    Science.gov (United States)

    Vandre, Eric; Carvalho, Marcio; Kumar, Satish

    2012-11-01

    Dynamic wetting involves the displacement of fluid on a solid surface by an advancing liquid, and is essential to the successful operation of coating processes. In this work, we consider a model problem in order to examine the influence of the displaced fluid on the failure of dynamic wetting. Full two-dimensional (2D) calculations over a broad range of parameters are performed using the finite element method (FEM), and the results are compared to prior experiments and asymptotic analysis. This comparison motivates the development of a novel and efficient hybrid computational method that combines 2D FEM for the liquid and lubrication theory for the displaced fluid. We will discuss the limits of applicability of the hybrid approach, and its ability to describe realistic coating flows. Overall, our results highlight the significant influence of the displaced fluid on the conditions at which dynamic wetting failure occurs, along with the underlying physical mechanisms.

  15. Page | 187 DISPLACEMENT AND ENVIRONMENTAL PROTECTION

    African Journals Online (AJOL)

    Fr. Ikenga

    development remain one of the greatest concerns of human beings globally.4. This urbanization which most often result in conflicts, ethnic violence, communal rife and clashes, and incessant tussle for natural and artificial resources, has also contributed to the displacement of persons. * By Obinna MBANUGO, LLM, BL, ...

  16. Earthquake source model using strong motion displacement

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  17. Geometric interpretation of density displacements and charge ...

    Indian Academy of Sciences (India)

    Unknown

    afresh from the density perspective. This conceptual DFT development has had a uni- fying influence on the reactivity theory. It combines the so-called electron following (EF) and electron preceding (EP) descriptions of both the closed and open molecular or reactive systems. In the former the nuclear displacements or the ...

  18. Heterodyne displacement interferometer, insensitive for input polarization

    NARCIS (Netherlands)

    Meskers, A.J.H.; Spronck, J.W.; Munnig Schmidt, R.H.

    2014-01-01

    Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error

  19. Isolated Displaced Fracture of the Lesser Tuberosity

    African Journals Online (AJOL)

    publication of this report. The authors declare no competing interests. Discussion. A delay in diagnosis of a lesser tuberosity fracture may lead to significant future clinical disability (2). In one such case the patient presented with axillary nerve neuropraxia while another case reported displacement of the biceps tendon (4).

  20. Olympic scale of sport-induced displacement

    Directory of Open Access Journals (Sweden)

    Jean du Plessis

    2007-07-01

    Full Text Available The Olympic Games have displaced more than two million people in the last 20 years, disproportionately affecting particular groups such as the homeless, the poor, Roma and African-Americans. Mega-events such as the Olympic Games often leave a negative housing legacy for local populations.

  1. Environmental conditions in displaced communities of Khartoum ...

    African Journals Online (AJOL)

    USER

    descriptive, cross-sectional survey design was used for a population of 726,989 inhabitants of the. Displaced communities in ..... (446) were cooking in the kitchen (67.4%), the remaining .... Table 3. Frequency and percentage distribution of the respondents by practice of personal hygiene and life style factors in Khartoum.

  2. Displacing Media: LCD LAB Artistic Residency

    Directory of Open Access Journals (Sweden)

    Filipe Pais

    2012-12-01

    Full Text Available This review refers to an artistic residency which took place at LCD LAB -  CAAA at Guimarães, in March, exploring a strategy for media art called Media Displacement. The text introduces the strategy very briefly and describes the residency's organization, structure, processses and the results produced.

  3. The Effect of Displacement Mode of Rigid Retaining Walls on Shearing Bands by Active Earth Pressure

    Directory of Open Access Journals (Sweden)

    A. Sekkel

    2013-10-01

    Full Text Available This work treats the physical modeling of failure mechanisms by active earth pressure. This last is developed by retaining wall movement. A lot of research showed that wall displacement has a significant effect on active earth pressure. A good comprehension of active earth pressure phenomenon and its failure mechanisms help us to better conceive retaining walls. The conception of a small-scale model allowed the realization of active earth pressure tests, while displacing the mobile wall toward the outside of the massif. The studied material is that of Schneebeli; light two-dimensional material made of cylindrical plastic rollers, simulating granular non-cohesive soil. The evolution of shearing zones under continuous and discontinuous displacement modes of mobile walls by correlation pictures allows the investigation of the localization of deformations and failure mechanisms.

  4. Gears and gear drives

    CERN Document Server

    Jelaska, Damir T

    2012-01-01

    Understanding how gears are formed and how they interact or 'mesh' with each other is essential when designing equipment that uses gears or gear trains. The way in which gear teeth are formed and how they mesh is determined by their geometry and kinematics, which is the topic of this book.  Gears and Gear Drives provides the reader with comprehensive coverage of gears and gear drives. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. Cylindric

  5. Displacement of oil by gas in power production

    International Nuclear Information System (INIS)

    Sundram, S.; Seng, L.K.; Kow, P.T.A.

    1992-01-01

    After the oil crises, Malaysia unveiled its four fuel diversification policy in the late 1970s towards utilization of gas, oil, coal and hydro. This was to ensure adequate and continuous energy supply for driving economic development and to cushion itself against impact of possible future fluctuations in oil prices. The primary energy supply in 1978 was predominantly oil based, consisting of 75.5% oil. As a result of this diversification policy, the oil component was reduced to about 51.8% in 1988. Due to its inherent ability to adapt and adjust to different fuels, the power sector played a crucial role in this massive shift away from oil. For the corresponding period, the oil component in the electricity generation input mix has decreased from 86.7% oil to 47.4%. Malaysia is endowed with substantial natural gas reserves amounting to 52.5 trillion cubic feet. Gas, therefore constitutes a natural and attractive option for the power sector in diversifying into non-oil indigenous energy resources, as the country's hydro potential has its limitations and the available proven coal reserves are relatively small. The paper addresses the past and current status and issues involved in displacing oil by gas for the power sector. These include the economic, technological and pricing aspects of natural gas development and issues pertaining to power system development. Future gas utilization strategies include the conversion of existing oil-fired plants to gas-fired, and the plant-up of gas turbines and the efficient combined cycle plants to meet the load requirements. These strategies are assessed from the viability and security perspective of increased gas utilization. Oil will continue to be displaced, but the extent to which gas will increase its share in power production is dependent on numerous factors ranging from its economics to supply security

  6. The influence of age-related health difficulties and attitudes toward driving on driving self-regulation in the baby boomer and older adult generations.

    Science.gov (United States)

    Conlon, Elizabeth G; Rahaley, Nicole; Davis, Jessica

    2017-05-01

    Our study aimed to determine how age- and disease-related difficulties were associated with attitudes and beliefs about driving self-regulation in men and women in the baby boomer and older generations. Three hundred and ninety-nine men (n=204) and women (n=195) aged between 48 and 91 years participated in a cross-sectional study of Australian drivers. Demographic characteristics and measures of driving confidence, driving difficulty and driving self-regulation; perceptions of visual, physical and cognitive capacity; and attitudes and beliefs about driving were obtained. Driving self-regulation in men and women was explained by different mechanisms. For men, self-report of visual and cognitive difficulties and poor driving confidence predicted driving self-regulation. For women, negative attitudes toward driving mediated the associations found between health-related difficulties and driving self-regulation. Barriers to driving self-regulation were not associated with the driving self-regulatory practices of men or women. Regardless of generation, women reported poorer driving confidence, greater driving difficulty and more driving self-regulation than men. We concluded that age- and disease-related difficulties are related to increasing driving self-regulation in mature men and women. These results indicate that different pathways are needed in models of driving self-regulation for men and women regardless of generational cohort. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Utilization of an ultrasound beam steering angle for measurements of tissue displacement vector and lateral displacement

    Directory of Open Access Journals (Sweden)

    Chikayoshi Sumi

    2010-09-01

    Full Text Available Chikayoshi SumiDepartment of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, Tokyo, JapanAbstract: A number of ultrasonic displacement/velocity measurement methods have been extensively developed for measurements of blood flow, tissue motion, and strain. Lateral modulation (LM methods have also been reported using steered, crossed beams, and these methods permit measurements of displacement vectors. In this report, a new beam steering method for the transmission and reception of ultrasound is proposed, which can enable measurements of lateral displacements and of arbitrary displacement vectors with a very high degree of accuracy. Because this beam steering method uses only a steering angle, this method is referred to as ASTA. With ASTA, the number of available methods to obtain a displacement vector measurement is limited to previously developed block-matching methods, such as the multidimensional cross-spectrum phase gradient method, and the multidimensional autocorrelation method (MAM and the multidimensional Doppler method (MDM using a block-matching method (the methods using block matching are referred to as MAMb and MDMb, respectively. Being dependent on the measurement method, only a lateral displacement measurement can be made even if the methods are multidimensional, ie, previously developed MAM and MDM using a moving average and a mirror setting of the obtained steered beams, and one-dimensional (1D, such as an autocorrelation method. Considerations of beamforming schemes using LM and ASTA show that the simple ASTA beamforming method increases capabilities for real-time measurements and requires a small physical aperture when compared with LM. For lateral displacement measurements (eg, blood flow in a carotid artery, a lateral coordinate must correspond to the direction of the target’s lateral motion, and the steering angle used is as large as possible to increase the measurement accuracy

  8. Multi performance option in direct displacement based design

    Directory of Open Access Journals (Sweden)

    Muljati Ima

    2017-01-01

    Full Text Available Compare to traditional method, direct displacement based design (DDBD offers the more rational design choice due to its compatibility with performance based design which is controlled by the targeted displacement in design. The objectives of this study are: 1 to explore the performance of DDBD for design Level-1, -2 and -3; 2 to determine the most appropriate design level based on material efficiency and damage risk; and 3 to verify the chosen design in order to check its performance under small-, moderate- and severe earthquake. As case study, it uses regular concrete frame structures consists of fourand eight-story with typical plan, located in low- and high-risk seismicity area. The study shows that design Level-2 (repairable damage is the most appropriate choice. Nonlinear time history analysis is run for each case study in order to verify their performance based on parameter: story drift, damage indices, and plastic mechanism. It can be concluded that DDBD performed very well in predicting seismic demand of the observed structures. Design Level-2 can be chosen as the most appropriate design level. Structures are in safe plastic mechanism under all level of seismicity although some plastic hinges formed at some unexpected locations.

  9. Imaging Correlations in Heterodyne Spectra for Quantum Displacement Sensing

    Science.gov (United States)

    Pontin, A.; Lang, J. E.; Chowdhury, A.; Vezio, P.; Marino, F.; Morana, B.; Serra, E.; Marin, F.; Monteiro, T. S.

    2018-01-01

    The extraordinary sensitivity of the output field of an optical cavity to small quantum-scale displacements has led to breakthroughs such as the first detection of gravitational waves and of the motions of quantum ground-state cooled mechanical oscillators. While heterodyne detection of the output optical field of an optomechanical system exhibits asymmetries which provide a key signature that the mechanical oscillator has attained the quantum regime, important quantum correlations are lost. In turn, homodyning can detect quantum squeezing in an optical quadrature but loses the important sideband asymmetries. Here we introduce and experimentally demonstrate a new technique, subjecting the autocorrelators of the output current to filter functions, which restores the lost heterodyne correlations (whether classical or quantum), drastically augmenting the useful information accessible. The filtering even adjusts for moderate errors in the locking phase of the local oscillator. Hence we demonstrate the single-shot measurement of hundreds of different field quadratures allowing the rapid imaging of detailed features from a simple heterodyne trace. We also obtain a spectrum of hybrid homodyne-heterodyne character, with motional sidebands of combined amplitudes comparable to homodyne. Although investigated here in a thermal regime, the method's robustness and generality represents a promising new approach to sensing of quantum-scale displacements.

  10. Oscillation control system for electric motor drive

    Science.gov (United States)

    Slicker, J.M.; Sereshteh, A.

    1988-08-30

    A feedback system for controlling mechanical oscillations in the torsionally complaint drive train of an electric or other vehicle. Motor speed is converted in a processor to estimate state signals in which a plant model which are used to electronically modify the torque commands applied to the motor. 5 figs.

  11. Comparing Expert and Novice Driving Behavior in a Driving Simulator

    Directory of Open Access Journals (Sweden)

    Hiran B. Ekanayake

    2014-02-01

    Full Text Available This paper presents a study focused on comparing driving behavior of expert and novice drivers in a mid-range driving simulator with the intention of evaluating the validity of driving simulators for driver training. For the investigation, measurements of performance, psychophysiological measurements, and self-reported user experience under different conditions of driving tracks and driving sessions were analyzed. We calculated correlations between quantitative and qualitative measures to enhance the reliability of the findings. The experiment was conducted involving 14 experienced drivers and 17 novice drivers. The results indicate that driving behaviors of expert and novice drivers differ from each other in several ways but it heavily depends on the characteristics of the task. Moreover, our belief is that the analytical framework proposed in this paper can be used as a tool for selecting appropriate driving tasks as well as for evaluating driving performance in driving simulators.

  12. Gaze-controlled Driving

    DEFF Research Database (Denmark)

    Tall, Martin; Alapetite, Alexandre; San Agustin, Javier

    2009-01-01

    We investigate if the gaze (point of regard) can control a remote vehicle driving on a racing track. Five different input devices (on-screen buttons, mouse-pointing low-cost webcam eye tracker and two commercial eye tracking systems) provide heading and speed control on the scene view transmitted...

  13. Drive-Through Training

    Science.gov (United States)

    Carter, Margie

    2010-01-01

    In this article, the author discusses how the early childhood field's approach to staff training reflects the drive-through, fast-food culture. Year after year directors send their teachers to workshops to get some quick refresher techniques. The author suggests that rather than focusing professional development on topics, focus on observing…

  14. Driving While Intoxicated.

    Science.gov (United States)

    Brick, John

    Alcohol intoxication increases the risk of highway accidents, the relative risk of crash probability increasing as a function of blood alcohol content (BAC). Because alcohol use is more prevalent than use of other drugs, more is known about the relationship between alcohol use and driving. Most states presume a BAC of .10% to be evidence of drunk…

  15. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  16. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Septon, Kendall K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-11

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  17. Investigation of a novel completely-in-the-canal direct-drive hearing device: a temporal bone study.

    Science.gov (United States)

    Mahboubi, Hossein; Paulick, Peyton; Kiumehr, Saman; Merlo, Mark; Bachman, Mark; Djalilian, Hamid Reza

    2013-01-01

    Whether a prototype direct-drive hearing device (DHD) is effective in driving the tympanic membrane (TM) in a temporal bone specimen to enable it to potentially treat moderate-to-severe hearing loss. Patient satisfaction with air conduction hearing aids has been low because of sound distortion, occlusion effect, and feedback issues. Implantable hearing aids provide a higher quality sound but require surgery for placement. The DHD was designed to combine the ability of driving the ossicular chain with placement in the external auditory canal. DHD is a 3.5-mm wide device that could fit entirely into the bony ear canal and directly drive the TM rather than use a speaker. A cadaveric temporal bone was prepared. The device developed in our laboratory was coupled to the external surface of the TM and against the malleus. Frequency sweeps between 300 Hz to 12 kHz were performed in 2 different coupling methods at 104 and 120 dB, and the DHD was driven with various levels of current. Displacements of the posterior crus of the stapes were measured using a laser Doppler vibrometer. The DHD showed a linear frequency response from 300 Hz to 12 kHz. Placement against the malleus showed higher amplitudes and lower power requirements than when the device was placed on the TM. DHD is a small completely-in-the-canal device that mechanically drives the TM. This novel device has a frequency output wider than most air conduction devices. Findings of the current study demonstrated that the DHD had the potential of being incorporated into a hearing aid in the future.

  18. Lepton flavor violation with displaced vertices

    Directory of Open Access Journals (Sweden)

    Julian Heeck

    2018-01-01

    Full Text Available If light new physics with lepton-flavor-violating couplings exists, the prime discovery channel might not be ℓ→ℓ′γ but rather ℓ→ℓ′X, where the new boson X could be an axion, majoron, familon or Z′ gauge boson. The most conservative bound then comes from ℓ→ℓ′+inv, but if the on-shell X can decay back into leptons or photons, displaced-vertex searches could give much better limits. We show that only a narrow region in parameter space allows for displaced vertices in muon decays, μ→eX,X→γγ,ee, whereas tauon decays can have much more interesting signatures.

  19. Remarks about the displaced spectra techniques

    International Nuclear Information System (INIS)

    Behringer, K.; Pineyro, J.

    1989-01-01

    In a recent paper a new method, called displaced spectra techniques, was presented for distinguishing between sinusoidal components and narrowband random noise contributions in otherwise random noise data. It is based on Fourier transform techniques, and uses the power spectral density (PSD) and a newly-introduced second-order displaced power spectra density (SDPSD) function. In order to distinguish between the two peak types, a validation criterion has been established. In this note, three topics are covered: a) improved numerical data for the validation criterion are given by using the refined estimation procedure of the PSD and SDPSD functions by the Welch method; b) the validation criterion requires the subtraction of the background below the peaks. A semiautomatic procedure is described; c) it was observed that peaks in the real part of the SDPSD function can be accompanied by fine structure phenomena which are unresolved in the PSD function. A few remarks are made about this problem. (author)

  20. Charge-displacement analysis for excited states

    Science.gov (United States)

    Ronca, Enrico; Pastore, Mariachiara; Belpassi, Leonardo; De Angelis, Filippo; Angeli, Celestino; Cimiraglia, Renzo; Tarantelli, Francesco

    2014-02-01

    We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place.

  1. Charge-displacement analysis for excited states

    International Nuclear Information System (INIS)

    Ronca, Enrico; Tarantelli, Francesco; Pastore, Mariachiara; Belpassi, Leonardo; De Angelis, Filippo; Angeli, Celestino; Cimiraglia, Renzo

    2014-01-01

    We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place

  2. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    Mohapatra, K.K.; Bose, Arun

    2014-01-01

    10 B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10 B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH) 4 - ) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10 B and 11 B

  3. Neogene displacements in the Solomon Islands Arc

    Science.gov (United States)

    Ridgway, J.

    1987-02-01

    The geology and present configuration of the Solomon Island arc can be explained in terms of the Neogene displacement of a single linear chain of islands. The central part of an original arc consisting of Bougainville, Choiseul, Santa Ysabel, Guadalcanal and San Cristobal was displaced to the northeast as a consequence of the attempted subduction of the Woodlark spreading system. Malaita arose on the northeastern side of the arc as a result of interaction between the arc and the Pacific Ocean floor and the volcanic islands of the New Georgia group formed to the southwest in response to the subduction of a spreading ridge, thus giving rise to the present double chain structure of the arc.

  4. Personal Exposure in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter Vilhelm

    1996-01-01

    Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification...... height is examined by means of full-scale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone. In the case of non-passive, heated...... in the lower part of the room close to the occupant. A personal exposure model for displacement ventilated rooms is proposed. The model takes the influence of gradients and the human thermal boundary layer into account. Two new quantities describing the interaction between a person and the ventilation...

  5. Rapid sexual and genomic isolation in sympatricDrosophilawithout reproductive character displacement.

    Science.gov (United States)

    Yukilevich, Roman; Maroja, Luana S; Nguyen, Kim; Hussain, Syed; Kumaran, Preethi

    2018-03-01

    The rapid evolution of sexual isolation in sympatry has long been associated with reinforcement (i.e., selection to avoid maladaptive hybridization). However, there are many species pairs in sympatry that have evolved rapid sexual isolation without known costs to hybridization. A major unresolved question is what evolutionary processes are involved in driving rapid speciation in such cases. Here, we focus on one such system; the Drosophila athabasca species complex, which is composed of three partially sympatric and interfertile semispecies: WN, EA, and EB. To study speciation in this species complex, we assayed sexual and genomic isolation within and between these semispecies in both sympatric and allopatric populations. First, we found no evidence of reproductive character displacement (RCD) in sympatric zones compared to distant allopatry. Instead, semispecies were virtually completely sexually isolated from each other across their entire ranges. Moreover, using spatial approaches and coalescent demographic simulations, we detected either zero or only weak heterospecific gene flow in sympatry. In contrast, within each semispecies we found only random mating and little population genetic structure, except between highly geographically distant populations. Finally, we determined that speciation in this system is at least an order of magnitude older than previously assumed, with WN diverging first, around 200K years ago, and EA and EB diverging 100K years ago. In total, these results suggest that these semispecies should be given full species status and we adopt new nomenclature: WN- D. athabasca , EA- D. mahican , and EB- D. lenape . While the lack of RCD in sympatry and interfertility do not support reinforcement, we discuss what additional evidence is needed to further decipher the mechanisms that caused rapid speciation in this species complex.

  6. Mechanical scanning in intravascular ultrasound imaging: Artifacts and driving mechanisms

    NARCIS (Netherlands)

    H. ten Hoff (H.); E.J. Gussenhoven (Elma); C.M. Korbijn (Carin); F. Mastik (Frits); C.T. Lancée (Charles); N. Bom (Klaas)

    1995-01-01

    textabstractObjective: Currently, intravascular ultrasound (US) imaging catheters are developed and produced to provide a complementary diagnostic method in the treatment of blood vessel obstructive disease. Typical catheter dimensions are a diameter of 1–2.5 mm and a length of 1–1.5 m. A real-time

  7. Computer simulation of displacement cascades in copper

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1983-06-01

    More than 500 displacement cascades in copper have been generated with the computer simulation code MARLOWE over an energy range pertinent to both fission and fusion neutron spectra. Three-dimensional graphical depictions of selected cascades, as well as quantitative analysis of cascade shapes and sizes and defect densities, illustrate cascade behavior as a function of energy. With increasing energy, the transition from production of single compact damage regions to widely spaced multiple damage regions is clearly demonstrated

  8. Environmentally-induced displacement and human security

    OpenAIRE

    Terminski, Bogumil

    2012-01-01

    We can distinguish two general causes of internal displacement worldwide: 1. the impact of threats to and ensuing decline in the level of human security below that needed for normal existence in the homeland territory, 2. administrative compulsion to leave the current place of residence. Every year, at least tens of millions of people on all continents are forced to leave their places of residence. The predominant cause is the occurrence of natural disasters, creating the most dynamic categor...

  9. Nested folded-beam suspensions with low longitudinal stiffness for comb-drive actuators

    International Nuclear Information System (INIS)

    Hou, Max T; Huang, Ming-Xian; Chang, Chao-Min

    2014-01-01

    Nested folded-beam suspensions with a low longitudinal spring constant and a high lateral spring constant have been used in comb-drive actuators. In the new design, every two flexible beams and two stiff members form a parallelogram flexure, which is considered as an ‘element’ of the nested folded-beam suspension. A set of these flexures of increasing size were placed one outside another to compose a nested structure. In this way, a serial mechanical connection between adjacent parallelogram flexures was formed; thus, a longer output stroke was obtained by combining the stroke displacements of all flexures in an additive fashion. The designed suspensions were theoretically analyzed and numerically simulated. Furthermore, comb-drive actuators with conventional and new suspensions were fabricated and tested to verify the predicted function. In the testing cases, the longitudinal spring constants of suspensions with two (conventional), three and four parallelogram flexures on each side were measured as 2.77, 1.75 and 1.36 N m −1 . The ratio among these three values was approximately 6:4:3, which is consistent with the theoretical predictions and simulation results. Microfabricated folded beams in series were achieved. (paper)

  10. Evolution of resistance to satyrization through reproductive character displacement in populations of invasive dengue vectors.

    Science.gov (United States)

    Bargielowski, Irka E; Lounibos, L Philip; Carrasquilla, María Cristina

    2013-02-19

    Recently, the highly invasive Asian tiger mosquito, Aedes albopictus, rapidly displaced resident populations of the yellow fever mosquito, Aedes aegypti in the southeastern United States and in Bermuda. Although multiple mechanisms of competitive displacement have been hypothesized, recent evidence of cross-insemination between these species in nature and the sterilizing effects of male accessory gland products asymmetrically favoring A. albopictus in interspecific matings support a role for satyrization (a form of reproductive interference) to explain the rapid displacements. Because of the drastic reproductive loss of A. aegypti females satyrized by A. albopictus males, we predicted selection for prezygotic isolation in populations of A. aegypti sympatric with A. albopictus. Exposures in cages demonstrated that female A. aegypti from populations in Florida sympatric with A. albopictus for the past 20 y were significantly less likely than nearby allopatric populations to mate with heterospecific males. Cross-inseminations of A. albopictus females by A. aegypti males were significantly less common, supporting the one-way direction of displacements observed in nature. Our results indicate rapid sexual selection leading to reproductive character displacement and the potential for satyr-resistant A. aegypti to recover from competitive displacements. These results have implications for increased risks of dengue transmission where these vector species meet worldwide.

  11. A euryarchaeal histone modulates strand displacement synthesis by replicative DNA polymerases.

    Science.gov (United States)

    Sun, Fei; Huang, Li

    2016-07-01

    Euryarchaeota and Crenarchaeota, the two main lineages of the domain Archaea, encode different chromatin proteins and differ in the use of replicative DNA polymerases. Crenarchaea possess a single family B DNA polymerase (PolB), which is capable of strand displacement modulated by the chromatin proteins Cren7 and Sul7d. Euryarchaea have two distinct replicative DNA polymerases, PolB and PolD, a family D DNA polymerase. Here we characterized the strand displacement activities of PolB and PolD from the hyperthermophilic euryarchaeon Pyrococcus furiosus and investigated the influence of HPfA1, a homolog of eukaryotic histones from P. furiosus, on these activities. We showed that both PolB and PolD were efficient in strand displacement. HPfA1 inhibited DNA strand displacement by both DNA polymerases but exhibited little effect on the displacement of a RNA strand annealed to single-stranded template DNA. This is consistent with the finding that HPfA1 bound more tightly to double-stranded DNA than to a RNA:DNA hybrid. Our results suggest that, although crenarchaea and euryarchaea differ in chromosomal packaging, they share similar mechanisms in modulating strand displacement by DNA polymerases during lagging strand DNA synthesis.

  12. Comparing Teaching Approaches About Maxwell's Displacement Current

    Science.gov (United States)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  13. Overloaded CDMA Systems with Displaced Binary Signatures

    Directory of Open Access Journals (Sweden)

    Vanhaverbeke Frederik

    2004-01-01

    Full Text Available We extend three types of overloaded CDMA systems, by displacing in time the binary signature sequences of these systems: (1 random spreading (PN, (2 multiple-OCDMA (MO, and (3 PN/OCDMA (PN/O. For each of these systems, we determine the time shifts that minimize the overall multiuser interference power. The achievable channel load with coded and uncoded data is evaluated for the conventional (without displacement and improved (with displacement systems, as well as for systems based on quasi-Welch-bound-equality (QWBE sequences, by means of several types of turbo detectors. For each system, the best performing turbo detector is selected in order to compare the performance of these systems. It is found that the improved systems substantially outperform their original counterparts. With uncoded data, (improved PN/O yields the highest acceptable channel load. For coded data, MO allows for the highest acceptable channel load over all considered systems, both for the conventional and the improved systems. In the latter case, channel loads of about 280% are achievable with a low degradation as compared to a single user system.

  14. Displacement Investigation of KNN-Bitumen-Based Piezoceramics in Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Ning Tang

    2018-01-01

    Full Text Available Piezoelectric material has excellent characteristics of electromechanical coupling so that it could be widely applied in structural health monitoring field. Nondestructive testing of piezoelectric technique becomes a research focus on piezoelectric field. Asphalt concrete produces cumulative damage under the multiple repeated vehicle load and natural situation, so it is suited material and structure for nondestructive application. In this study, a test system was established by driving power of piezoceramic, laser displacement sensor, computer, and piezo-embedded asphalt concrete. Displacement, hysteresis, creeps, and dynamic behavior of KNN piezoceramic element embedded in asphalt concrete were tested. The results indicate that displacement output attained 0.4 μm to 0.7 μm when the loads were from 0 N to 150 N. The hysteresis was not obvious when the load was from 0 N to 100 N, aside from higher loads. The creep phenomenon can be divided into two parts: uptrend and balance. The more serious the asphalt binder ageing is, the larger the displacement is, when piezo-asphalt concrete has already been in serious ageing.

  15. Force-displacement response of unreinforced masonry walls for seismic design

    International Nuclear Information System (INIS)

    Petry, S.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology EPFL contributes to the improvement of the design and assessment methods for unreinforced masonry (URM) wall structures built with modern hollow core clay bricks. First, an experimental campaign on the lateral nonlinear in-plane response of URM walls is presented; secondly, an existing dataset on URM walls is extended and reanalysed. A newly developed mechanical model which describes the full force-displacement response of URM walls is described. Two series of URM walls tested under lateral in-plane loading are presented. Throughout the quasi-cyclic tests of all URM walls, the deformations were recorded using a digital photogrammetric measurement system which tracked the displacement field of the walls. Based on these findings, a new mechanical model is proposed which describes the nonlinear force-displacement response of flexural dominated URM walls up to near collapse

  16. Displacement fields from point cloud data: Application of particle imaging velocimetry to landslide geodesy

    Science.gov (United States)

    Aryal, Arjun; Brooks, Benjamin A.; Reid, Mark E.; Bawden, Gerald W.; Pawlak, Geno

    2012-01-01

    Acquiring spatially continuous ground-surface displacement fields from Terrestrial Laser Scanners (TLS) will allow better understanding of the physical processes governing landslide motion at detailed spatial and temporal scales. Problems arise, however, when estimating continuous displacement fields from TLS point-clouds because reflecting points from sequential scans of moving ground are not defined uniquely, thus repeat TLS surveys typically do not track individual reflectors. Here, we implemented the cross-correlation-based Particle Image Velocimetry (PIV) method to derive a surface deformation field using TLS point-cloud data. We estimated associated errors using the shape of the cross-correlation function and tested the method's performance with synthetic displacements applied to a TLS point cloud. We applied the method to the toe of the episodically active Cleveland Corral Landslide in northern California using TLS data acquired in June 2005–January 2007 and January–May 2010. Estimated displacements ranged from decimeters to several meters and they agreed well with independent measurements at better than 9% root mean squared (RMS) error. For each of the time periods, the method provided a smooth, nearly continuous displacement field that coincides with independently mapped boundaries of the slide and permits further kinematic and mechanical inference. For the 2010 data set, for instance, the PIV-derived displacement field identified a diffuse zone of displacement that preceded by over a month the development of a new lateral shear zone. Additionally, the upslope and downslope displacement gradients delineated by the dense PIV field elucidated the non-rigid behavior of the slide.

  17. Driving systems: innovations - trends - mechatronics; Antriebssysteme: Innovationen - Trends - Mechatronik

    Energy Technology Data Exchange (ETDEWEB)

    Binder, A. [Technische Univ. Darmstadt (Germany). Inst. fuer Elektrische Energiewandlung; Doppelbauer, M. [SEW-Eurodrive GmbH und Co.KG, Bruchsal (DE). Entwicklung und Konstruktion Motoren (EML); Gold, P.W. [RWTH Aachen (Germany). Inst. fuer Maschinenelemente und Maschinengestaltung; Hofmann, W. [Technische Univ. Chemnitz (Germany). Lehrstuhl fuer Elektrische Maschinen und Antriebe

    2007-03-15

    Short overview on this special meeting with interdisciplinary topics of connection between mechanical and electrical engineering: mechatronics. The main topics are covered by the fields motion control, simulation of drives, monitoring, gears, motors engineering/-design, converter systems, industrial applications and drives for wind turbines. (GL)

  18. Position Control of an Over‐Actuated Direct Hydraulic Cylinder Drive

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Grønkjær, Morten; Pedersen, Henrik Clemmensen

    2017-01-01

    This paper considers the analysis and control strategy for a novel direct hydraulic cylinder drive, that is overactuated in the sense that it has more inputs than sensible outputs. Efforts to overcome the inherent loss of energy due to th+rottling in valve driven hydraulic drives are many......, and various approaches have been proposed by research communities as well as the industry. Recently, a so-called Speed-variable Switched Differential Pump was proposed for direct drive of hydraulic differential cylinders. The main idea with this drive is to utilize an electric rotary drive with the shaft...... connected to three oppositely oriented fixed displacement gear pumps to actuate a differential cylinder. To ensure a high stiffness of the drive, this is constructed such that the transmission line pressures will increase for pump output flows exceeding pump leakages, and proportional valves provides...

  19. Improvements of Piezo-Actuated Stick–Slip Micro-Drives: Modeling and Driving Waveform

    Directory of Open Access Journals (Sweden)

    Xuan-Ha Nguyen

    2018-02-01

    Full Text Available Modeling and waveform optimization are important research topics for piezo-actuated stick–slip micro-drives. In this paper, the dynamics of piezo-actuated stick–slip micro-drives (PASSMDs are theoretically investigated. We introduce an extended model taking the dynamics of the piezo actuators into account. The model combines the whole macroscopic movement of the drive’s runner and actuators and the microscopic behavior of the frictional contacts in a hybrid dynamic simulation. The macroscopic movements are described via Newtonian mechanics, while the microscopic behavior is computed using the method of dimensionality reduction. Two important characteristics of the drive, the critical actuation amplitude and the force generation, are systematically analyzed. The numerical simulation results show a fine agreement with experimental data of the previously published work. The critical actuation amplitude is found to depend on the behavior of the guiding contacts, the dynamics of the actuators and their interaction. Furthermore, a novel driving waveform, which allows us to increase the operational velocity for the drive, is proposed. The waveform is derived by exploiting micro-vibration and considering the dynamic contact status. Simulation results show that the average velocity of the drive is heightened by about 15 % . The performance of the drive is therefore improved.

  20. Displacement Models for THUNDER Actuators having General Loads and Boundary Conditions

    Science.gov (United States)

    Wieman, Robert; Smith, Ralph C.; Kackley, Tyson; Ounaies, Zoubeida; Bernd, Jeff; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    This paper summarizes techniques for quantifying the displacements generated in THUNDER actuators in response to applied voltages for a variety of boundary conditions and exogenous loads. The PDE (partial differential equations) models for the actuators are constructed in two steps. In the first, previously developed theory quantifying thermal and electrostatic strains is employed to model the actuator shapes which result from the manufacturing process and subsequent repoling. Newtonian principles are then employed to develop PDE models which quantify displacements in the actuator due to voltage inputs to the piezoceramic patch. For this analysis, drive levels are assumed to be moderate so that linear piezoelectric relations can be employed. Finite element methods for discretizing the models are developed and the performance of the discretized models are illustrated through comparison with experimental data.