WorldWideScience

Sample records for forced displacement characteristics

  1. Force transmissibility versus displacement transmissibility

    Science.gov (United States)

    Lage, Y. E.; Neves, M. M.; Maia, N. M. M.; Tcherniak, D.

    2014-10-01

    It is well-known that when a single-degree-of-freedom (sdof) system is excited by a continuous motion of the foundation, the force transmissibility, relating the force transmitted to the foundation to the applied force, equals the displacement transmissibility. Recent developments in the generalization of the transmissibility to multiple-degree-of-freedom (mdof) systems have shown that similar simple and direct relations between both types of transmissibility do not appear naturally from the definitions, as happens in the sdof case. In this paper, the authors present their studies on the conditions under which it is possible to establish a relation between force transmissibility and displacement transmissibility for mdof systems. As far as the authors are aware, such a relation is not currently found in the literature, which is justified by being based on recent developments in the transmissibility concept for mdof systems. Indeed, it does not appear naturally, but the authors observed that the needed link is present when the displacement transmissibility is obtained between the same coordinates where the applied and reaction forces are considered in the force transmissibility case; this implies that the boundary conditions are not exactly the same and instead follow some rules. This work presents a formal derivation of the explicit relation between the force and displacement transmissibilities for mdof systems, and discusses its potential and limitations. The authors show that it is possible to obtain the displacement transmissibility from measured forces, and the force transmissibility from measured displacements, opening new perspectives, for example, in the identification of applied or transmitted forces. With this novel relation, it becomes possible, for example, to estimate the force transmissibility matrix with the structure off its supports, in free boundary conditions, and without measuring the forces. As far as force identification is concerned, this

  2. Hydrodynamic Excitation Forces on Floating Structures with Finite Displacements

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt; Nielsen, Søren R. K.

    2015-01-01

    excitation force is solely a function of time, hence the body is fixed in reference to the wave field. In this paper, the instantaneous position of the body is included in the calculation of the excitation force. Even though the displacement of the structure relative to a characteristic wavelength...

  3. Serial forced displacement in American cities, 1916-2010.

    Science.gov (United States)

    Fullilove, Mindy Thompson; Wallace, Rodrick

    2011-06-01

    Serial forced displacement has been defined as the repetitive, coercive upheaval of groups. In this essay, we examine the history of serial forced displacement in American cities due to federal, state, and local government policies. We propose that serial forced displacement sets up a dynamic process that includes an increase in interpersonal and structural violence, an inability to react in a timely fashion to patterns of threat or opportunity, and a cycle of fragmentation as a result of the first two. We present the history of the policies as they affected one urban neighborhood, Pittsburgh's Hill District. We conclude by examining ways in which this problematic process might be addressed.

  4. The Right to Inhabit. Reflection on Forced Displacement and Social Movements.

    Directory of Open Access Journals (Sweden)

    Reyna Sánchez Estévez

    2016-12-01

    Full Text Available This paper exposes initial data from an investigation into the protests and social struggles against forced displacement of people from Mexico, it is given to know the places where protests are developed, the reasons which originate them and the characteristics of the participant subjects, a first analysis of the resistance objectives is also done and some elements of their repertoires of protest are offered. A reflection on the damage caused by these displacements in human beings and on the notions of risk and vulnerability is made.Keywords: Social movements, evictions, vulnerability

  5. Displacement and force coupling control design for automotive active front steering system

    Science.gov (United States)

    Zhao, Wanzhong; Zhang, Han; Li, Yijun

    2018-06-01

    A displacement and force coupling control design for active front steering (AFS) system of vehicle is proposed in this paper. In order to investigate the displacement and force characteristics of the AFS system of the vehicle, the models of AFS system, vehicle, tire as well as the driver model are introduced. Then, considering the nonlinear characteristics of the tire force and external disturbance, a robust yaw rate control method is designed by applying a steering motor to generate an active steering angle to adjust the yaw stability of the vehicle. Based on mixed H2/H∞ control, the system robustness and yaw rate tracking performance are enforced by H∞ norm constraint and the control effort is captured through H2 norm. In addition, based on the AFS system, a planetary gear set and an assist motor are both added to realize the road feeling control in this paper to dismiss the influence of extra steering angle through a compensating method. Evaluation of the overall system is accomplished by simulations and experiments under various driving condition. The simulation and experiment results show the proposed control system has excellent tracking performance and road feeling performance, which can improve the cornering stability and maneuverability of vehicle.

  6. Flow Characteristics and Sizing of Annular Seat Valves for Digital Displacement Machines

    Directory of Open Access Journals (Sweden)

    Christian Nørgård

    2018-01-01

    Full Text Available This paper investigates the steady-state flow characteristics and power losses of annular seat valves for digital displacement machines. Annular seat valves are promising candidates for active check-valves used in digital displacement fluid power machinery which excels in efficiency in a broad operating range. To achieve high machine efficiency, the valve flow losses and the required electrical power needed for valve switching should be low. The annular valve plunger geometry, of a valve prototype developed for digital displacement machines, is parametrized by three parameters: stroke length, seat radius and seat width. The steady-state flow characteristics are analyzed using static axi-symmetric computational fluid dynamics. The pressure drops and flow forces are mapped in the valve design space for several different flow rates. The simulated results are compared against measurements using a valve prototype. Using the simulated maps to estimate the flow power losses and a simple generic model to estimate the electric power losses, both during digital displacement operation, optimal designs of annular seat valves, with respect to valve power losses, are derived under several different operating conditions.

  7. Internal Displacement and Forced Migration within Zimbabwe: An ...

    African Journals Online (AJOL)

    This paper argues that, contrary to the picture portrayed by the government of Zimbabwe, internal displacement, as one form of (forced) migration within a country's borders, is more prevalent in the country than is at first discernable. The paper offers an overview of the current scholarship on the forced mobility of particular ...

  8. War, forced displacement and growth in Laotian adults.

    Science.gov (United States)

    Clarkin, Patrick F

    2012-01-01

    Evidence from several populations suggests that war negatively impacts civilian nutrition, physical growth and overall health. This effect is often enduring or permanent, particularly if experienced early in life. To assess whether the number of lifetime displacement experiences and being displaced in infancy were associated with adult height, sitting height, leg length and the sitting height ratio. Retrospective questionnaires on displacement and resettlement experiences and anthropometric data were collected from a sample of Laotian adult refugees (ethnic Hmong and Lao; n = 365). All were born in Laos or Thailand and had resettled in French Guiana or the US. Many had been displaced several times by military conflict in Laos. In bivariate analyses, being displaced in infancy and the number of lifetime displacement experiences one had were negatively associated with final adult height and leg length in both sexes. The association was stronger in females, particularly Hmong females. There was no significant association between total displacement experiences and the sitting height ratio. In multiple regression analyses, linear growth in males was negatively associated with being displaced in infancy; in females, the number of lifetime displacement experiences was a significant predictor. Forced displacement from war appears to have a lasting effect on final adult height, sitting height and leg length, although not necessarily on the sitting height ratio in this sample.

  9. Modelling magnetic forces during asymmetric vertical displacement events at JET

    International Nuclear Information System (INIS)

    Riccardo, V.; Walker, S.; Noll, P.

    2000-01-01

    Asymmetric vertical disruption events (AVDEs) are fortunately rare, but can induce large lateral forces which can cause significant mechanical damage to tokamaks. In this paper we present a simple model which allows the lateral forces generated during such a disruption to be estimated as a function of relatively easily obtained electromagnetic parameters: the asymmetries in the vertical current moment. This model is validated by using it to predict the displacement history of the JET tokamak caused by a number of major AVDEs. It is shown that the predicted forces and displacements agree well with quantities measured during these disruptions. One conclusion from the model is that the maximum sideways displacement scales with the product of the plasma current and the toroidal field, and this recipe is now used at JET to assess a priori the hazards of performing high current and high field pulses when they are known to be likely to disrupt. (author)

  10. Displacement of organelles in plant gravireceptor cells by vibrational forces and ultrasound.

    Science.gov (United States)

    Kuznetsov, O.; Nechitailo, G.; Kuznetsov, A.

    Plant gravity perception can be studied by displacing statoliths inside receptor cells by forces other than gravity. Due to mechanical heterogeneity of statocytes various ponderomotive forces can be used for this purpose. In a plant subjected to non- symmetric vibrations statoliths experience inertial force proportional to the difference between their density and that of cytoplasm and to the instantaneous acceleration of the cell. This force causes cyclic motion of statoliths relative to cytoplasm and, depending on the profile of oscillations, can result in a net displacement of them (due to complex rheology of the cell interior), similar to sedimentation. This can be described as "vibrational" ponderomotive force acting on the statoliths. Vertically growing Arabidopsis seedlings, subjected to horizontal, sawtooth shaped oscillations (250 Hz, 1.5 mm amplitude), showed 17+/-2o root curvature toward and shoot curvature of 11+/-3o against the stronger acceleration. When the polarity of the oscillations was reversed, the direction of curvature of shoots and roots was also reversed. Control experiments with starchless mutants (TC7) produced no net curvature, which indicates that dense starch-filled amyloplasts are needed for the effect. These control experiments also eliminate touch-induced reactions or other side-effects as the cause of the curvature. Linum roots curved 25+/-7o . Ceratodon protonemata subjected to the same oscillations have shown displacement of plastids and curvature consistent with the pattern observed during graviresponse: positively gravitropic wwr mutant curved in the direction of the plastid displacement, WT curved in the opposite direction. Acoustic ponderomotive forces, originating from transfer of a sonic beam momentum to the medium due to sound scattering and attenuation in a mechanically heterogeneous system, also can displace statoliths. Vertical flax seedlings curved away from the ultrasonic source (800 kHz, 0.1 W/cm2 ) presumably as a

  11. 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.

  12. 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

  13. 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%.

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

    International Nuclear Information System (INIS)

    Muralidhara; Rao, Rathnamala

    2015-01-01

    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%.

  15. [Stigma and Mental Health in Victims of Colombia's Internal Armed Conflict in Situation of Forced Displacement].

    Science.gov (United States)

    Campo-Arias, Adalberto; Herazo, Edwin

    2014-01-01

    The prolonged sociopolitical phenomenon of Colombian violence generated a high number of victims, many of whom suffered a continual process of internal displacement and stigma-discrimination complex. To postulate possible mechanisms by which victims of Colombia's internal armed conflict in a situation of forced displacement were stigmatized and discriminated. Stigma affects mental health, not only because it represents a major stressor for discriminated individuals and groups, but also because it accounts for inequalities and inequities in health. Initially, as the victims of the internal armed conflict in situation of forced displacement were not considered as such, but as responsible for the situation. Thus, they had to cope with the social and economic inequalities, explained partially by low categorization or status that they received, possibly due to poor construction of social capital in the country. Also, victims of the internal armed conflict suffer from intersectional stigma and discrimination due to other characteristics such as gender, sexual orientation, ethnic-racial origin, or meeting criteria for a mental disorder. An active process of inclusive social development is required for the displaced victims of the armed conflict,in order to reduce multiple stigma and ensure their mental health. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  16. Forced migration and mental health: prolonged internal displacement, return migration and resilience.

    Science.gov (United States)

    Siriwardhana, Chesmal; Stewart, Robert

    2013-03-01

    Forced internal displacement has been rising steadily, mainly due to conflict. Many internally displaced people (IDP) experience prolonged displacement. Global research evidence suggests that many of these IDP are at high risk for developing mental disorders, adding weight to the global burden of disease. However, individual and community resilience may act as protective factors. Return migration may be an option for some IDP populations, especially when conflicts end, although return migration may itself be associated with worse mental health. Limited evidence is available on effects of resettlement or return migration following prolonged forced internal displacement on mental health. Also, the role of resilience factors remains to be clarified following situations of prolonged displacement. The public health impact of internal displacement is not clearly understood. Epidemiological and interventional research in IDP mental health needs to look beyond medicalised models and encompass broader social and cultural aspects. The resilience factor should be integrated and explored more in mental health research among IDP and a clearly focused multidisciplinary approach is advocated.

  17. Study on the development of passive MR damper with displacement-dependent damping characteristics

    International Nuclear Information System (INIS)

    Murakami, Takahiro; Sakai, Michiya; Nakano, Masami

    2010-01-01

    In this paper, we propose a new concept of a magneto-rheological (MR) fluid damper, which is a passive MR fluid damper. The passive MR damper has no electrical devices, such as a sensor, power supply and controller, and hence, it has an advantage in reliability and cost compared with semi-active MR dampers. Moreover, the proposed MR damper can be designed to have a variable damping force in response to its displacement. In this paper, the dynamic performance of the passive MR damper is experimentally demonstrated. The prototype of the proposed damper has been manufactured in order to verify the dynamic performance. The displacement excitation test result of the damper demonstrates that the damping characteristics depend on its displacement amplitude, that is, the damper behaves as a linear viscous damper under small vibrations and develops much higher damping performance under large vibrations. (author)

  18. Biomechanical characteristics of self-ligating brackets in a vertically displaced canine model: a finite element analysis.

    Science.gov (United States)

    Kim, S-J; Kwon, Y-H; Hwang, C-J

    2016-05-01

    The objective of this study was to compare the biomechanical characteristics between two types of self-ligating brackets and conventional metal brackets using finite element analysis of a vertically displaced canine model focusing on the desired force on the canine and undesirable forces on adjacent teeth. Three-dimensional finite element models of the maxillary dentition with 1-mm, 2-mm, and 3-mm vertically displaced canines were constructed. Two different self-ligating brackets (In-Ovation C and Smart clip) and a conventional metal bracket (Micro-arch) were modeled. After a 0.016-inch NiTi (0.40 mm, round) wire was engaged, the displacement of each tooth was calculated using x-, y-, and z-coordinates, and the tensile and compressive stresses were calculated. The extrusion and maximal tensile stress of the canine differed little between the three brackets, but the intrusion and minimal compressive stress values of the adjacent teeth differed considerably and were highest in the Smart clip and least in the In-Ovation C. The extrusion and maximal tensile stress of the canine in the 3-mm displacement model was less than that in the 2-mm displacement model, and the intrusion and minimal compressive stress of the adjacent teeth increased with the degree of displacement. Self-ligating brackets were not superior to conventional brackets in leveling a vertically displaced canine. A continuous arch wire may not be recommended for leveling of severely displaced canines whether using self-ligating or conventional brackets. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Simple force balance accelerometer/seismometer based on a tuning fork displacement sensor

    International Nuclear Information System (INIS)

    Stuart-Watson, D.; Tapson, J.

    2004-01-01

    Seismometers and microelectromechanical system accelerometers use the force-balance principle to obtain measurements. In these instruments the displacement of a mass object by an unknown force is sensed using a very high-resolution displacement sensor. The position of the object is then stabilized by applying an equal and opposite force to it. The magnitude of the stabilizing force is easily measured, and is assumed to be equivalent to the unknown force. These systems are critically dependent on the displacement sensor. In this article we use a resonant quartz tuning fork as the sensor. The tuning fork is operated so that its oscillation is lightly damped by the proximity of the movable mass object. Changes in the position of the mass object cause changes in the phase of the fork's resonance; this is used as the feedback variable in controlling the mass position. We have developed an acceleration sensor using this principle. The mass object is a piezoelectric bimorph diaphragm which is anchored around its perimeter, allowing direct electronic control of the displacement of its center. The tuning fork is brought very close to the diaphragm center, and is connected into a self-oscillating feedback circuit which has phase and amplitude as outputs. The diaphragm position is adjusted by a feedback loop, using phase as the feedback variable, to keep it in a constant position with respect to the tuning fork. The measured noise for this sensor is approximately 10.0 mg in a bandwidth of 100 Hz, which is substantially better than commercial systems of equivalent cost and size

  20. Urban IDPs and Poverty: Analysis of the Effect of Mass Forced Displacement on Urban Poverty in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Nermin Oruc

    2015-06-01

    Full Text Available This paper analyzes the effect of mass forced displacement on urban poverty in Bosnia and Herzegovina. The process of displacement in Bosnia and Herzegovina involved “forced evictions”, implying no choice in displacement decision, meaning that this type of rural-urban migration was not a rational decision driven by economic motives. Consequently, this can possibly lead to a larger incidence of poverty among displaced people. The paper starts with a discussion of the specific features of the process of forced displacement and their possibly different effect on urban poverty compared to voluntary migration, based on qualitative evidence collected through interviews with people who experienced forced displacement during the conflict in the 1990s. Then, the probit model of determinants of poverty, based on the Living Standards Measurement Survey data, was estimated in order to provide empirical evidence of the effect of mass forced displacement on urban poverty, as well as the difference in the poverty incidence among displaced people compared to voluntary migrants. The results suggest that consumption is significantly lower among displaced households, while incidence of poverty is not affected by displacement status. The evidence also contributes to the migration literature by providing specific results about the relationship between mass forced displacement and urban poverty.

  1. Force-displacement measurements of earlywood bordered pits using a mesomechanical tester.

    Science.gov (United States)

    Zelinka, Samuel L; Bourne, Keith J; Hermanson, John C; Glass, Samuel V; Costa, Adriana; Wiedenhoeft, Alex C

    2015-10-01

    The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms, and pit aspiration plays a large role in wood technological applications such as wood drying and preservative treatment. Here we present force-displacement measurements for pit membranes of circular bordered pits, collected on a mesomechanical testing system. The system consists of a quartz microprobe attached to a microforce sensor that is positioned and advanced with a micromanipulator mounted on an inverted microscope. Membrane displacement is measured from digital image analysis. Unaspirated pits from earlywood of never-dried wood of Larix and Pinus and aspirated pits from earlywood of dried wood of Larix were tested to generate force-displacement curves up to the point of membrane failure. Two failure modes were observed: rupture or tearing of the pit membrane by the microprobe tip, and the stretching of the pit membrane until the torus was forced out of the pit chamber through the pit aperture without rupture, a condition we refer to as torus prolapse. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  2. The everyday violence of forced displacement : community, memory and identity politics among Kurdish internal forced migrants in Turkey

    NARCIS (Netherlands)

    Geerse, M.T.

    2011-01-01

    Kurds in Turkey: the everyday violence of their forced displacement. Roughly fifteen years ago, more than one million Kurds were forcibly displaced from their villages in Southeast Turkey, mostly by Turkish security troops, who were engaged in a violent struggle with the PKK, an armed organization

  3. 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.

  4. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    International Nuclear Information System (INIS)

    Qin Yujie; Hou Xiaojing

    2011-01-01

    Research highlights: → The relaxation properties of maglev forces have been investigated simultaneously. → Influence of relaxation on forces of HTSC subjected to different LDs above PMG is different. → The influence is explained based on motion of flux lines, re/demagnetization of HTSC during LD. → The work provide a scientific analysis for the practical application of the bulk HTSC. - Abstract: This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  5. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Qin Yujie, E-mail: qyjswjtu@vip.sohu.co [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China); Hou Xiaojing [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China)

    2011-02-15

    Research highlights: {yields} The relaxation properties of maglev forces have been investigated simultaneously. {yields} Influence of relaxation on forces of HTSC subjected to different LDs above PMG is different. {yields} The influence is explained based on motion of flux lines, re/demagnetization of HTSC during LD. {yields} The work provide a scientific analysis for the practical application of the bulk HTSC. - Abstract: This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  6. Force sensing using 3D displacement measurements in linear elastic bodies

    Science.gov (United States)

    Feng, Xinzeng; Hui, Chung-Yuen

    2016-07-01

    In cell traction microscopy, the mechanical forces exerted by a cell on its environment is usually determined from experimentally measured displacement by solving an inverse problem in elasticity. In this paper, an innovative numerical method is proposed which finds the "optimal" traction to the inverse problem. When sufficient regularization is applied, we demonstrate that the proposed method significantly improves the widely used approach using Green's functions. Motivated by real cell experiments, the equilibrium condition of a slowly migrating cell is imposed as a set of equality constraints on the unknown traction. Our validation benchmarks demonstrate that the numeric solution to the constrained inverse problem well recovers the actual traction when the optimal regularization parameter is used. The proposed method can thus be applied to study general force sensing problems, which utilize displacement measurements to sense inaccessible forces in linear elastic bodies with a priori constraints.

  7. The Force-Displacement Relationship in Commonly Used Resuscitation Manikins: Not Very Human

    DEFF Research Database (Denmark)

    Thomsen, Jakob E; Stærk, Mathilde; Løfgren, Bo

    2017-01-01

    Introduction: Manikins are widely used for CPR training and designed to simulate a human in cardiac arrest. Previous studies show a non-linear force-displacement relationship in the human chest. This may not be the case for resuscitation manikins. The aim of this study was to investigate the force......-displacement relationship in commonly used resuscitation manikins.Methods: Commonly used infant and adult manikins for resuscitation training were included in the study. Manikins were tested by placing them in a material testing machine (ProLine Z050, Zwick/Roell, Ulm, Germany). A piston was placed on lower half...... (Laerdal) and CPR Anytime® Infant (inflatable; American Heart Association) and five adult manikins: Mini Anne (inflatable), Little Anne®, Resusci Anne, Resusci Anne Advanced(Laerdal) and Ambu® Man (Ambu). Infant manikins required a force of 57 N and 34 N to compress the chest 3 cm. The force required...

  8. ERDBEBEN, Structure Displacements and Forces Under Earthquake Conditions

    International Nuclear Information System (INIS)

    Brandhuber, F.

    1977-01-01

    1 - Nature of physical problem solved: ERDBEBEN calculates the displacements and forces of a structure, excited by an earthquake. 2 - Method of solution: The mathematical method is the 'response spectrum modal analysis'. Before calculation, the user of ERDBEBEN has to idealize the structure with finite elements and to calculate its eigenfrequencies with the program NASTRAN (level 15). The superposition of the Eigen-forms will be done by the 'root mean square method'. 3 - Restrictions on the complexity of the problem: The length of the arrays can be variable (parameter card). Only the number of the different types of finite elements cannot be more than 5. The program calculates the element forces only for beam and spring elements

  9. Characterizing absolute piezoelectric microelectromechanical system displacement using an atomic force microscope

    International Nuclear Information System (INIS)

    Evans, J.; Chapman, S.

    2014-01-01

    Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided

  10. Characterizing absolute piezoelectric microelectromechanical system displacement using an atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J., E-mail: radiant@ferrodevices.com; Chapman, S., E-mail: radiant@ferrodevices.com [Radiant Technologies, Inc., 2835C Pan American Fwy NE, Albuquerque, New Mexico 87107 (United States)

    2014-08-14

    Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided.

  11. Internally displaced "victims of armed conflict" in Colombia: the trajectory and trauma signature of forced migration.

    Science.gov (United States)

    Shultz, James M; Garfin, Dana Rose; Espinel, Zelde; Araya, Ricardo; Oquendo, Maria A; Wainberg, Milton L; Chaskel, Roberto; Gaviria, Silvia L; Ordóñez, Anna E; Espinola, Maria; Wilson, Fiona E; Muñoz García, Natalia; Gómez Ceballos, Angela Milena; Garcia-Barcena, Yanira; Verdeli, Helen; Neria, Yuval

    2014-10-01

    While conflict-induced forced migration is a global phenomenon, the situation in Colombia, South America, is distinctive. Colombia has ranked either first or second in the number of internally displaced persons for 10 years, a consequence of decades of armed conflict compounded by high prevalence of drug trafficking. The displacement trajectory for displaced persons in Colombia proceeds through a sequence of stages: (1) pre-expulsion threats and vulnerability, (2) expulsion, (3) migration, (4) initial adaptation to relocation, (5) protracted resettlement (the end point for most forced migrants), and, rarely, (6) return to the community of origin. Trauma signature analysis, an evidence-based method that elucidates the physical and psychological consequences associated with exposures to harm and loss during disasters and complex emergencies, was used to identify the psychological risk factors and potentially traumatic events experienced by conflict-displaced persons in Colombia, stratified across the phases of displacement. Trauma and loss are experienced differentially throughout the pathway of displacement.

  12. Internally Displaced “Victims of Armed Conflict” in Colombia: The Trajectory and Trauma Signature of Forced Migration

    Science.gov (United States)

    Shultz, James M.; Garfin, Dana Rose; Espinel, Zelde; Araya, Ricardo; Oquendo, Maria A.; Wainberg, Milton L.; Chaskel, Roberto; Gaviria, Silvia L.; Ordóñez, Anna E.; Espinola, Maria; Wilson, Fiona E.; García, Natalia Muñoz; Ceballos, Ángela Milena Gómez; Garcia-Barcena, Yanira; Verdeli, Helen; Neria, Yuval

    2016-01-01

    While conflict-induced forced migration is a global phenomenon, the situation in Colombia, South America, is distinctive. Colombia has ranked either first or second in the number of internally displaced persons for 10 years, a consequence of decades of armed conflict compounded by high prevalence of drug trafficking. The displacement trajectory for displaced persons in Colombia proceeds through a sequence of stages: (1) pre-expulsion threats and vulnerability, (2) expulsion, (3) migration, (4) initial adaptation to relocation, (5) protracted resettlement (the end point for most forced migrants), and, rarely, (6) return to the community of origin. Trauma signature analysis, an evidence-based method that elucidates the physical and psychological consequences associated with exposures to harm and loss during disasters and complex emergencies, was used to identify the psychological risk factors and potentially traumatic events experienced by conflict-displaced persons in Colombia, stratified across the phases of displacement. Trauma and loss are experienced differentially throughout the pathway of displacement. PMID:25135775

  13. Atomic force microscope cantilever as an encoding sensor for real-time displacement measurement

    International Nuclear Information System (INIS)

    Chen, Xiaomei; Koenders, Ludger; Wolff, Helmut; Haertig, Frank; Schilling, Meinhard

    2010-01-01

    A tuning fork-based atomic force microscope cantilever has been investigated for application as an encoding sensor for real-time displacement measurement. The algorithm used to encode the displacement is based on the direct count of the integer pitches of a known grating, and the calculation of the fractional parts of a pitch at the beginning and during displacement. A cross-correlation technique has been adopted and applied to the real-time signal filtering process for the determination of the pitch during scanning by using a half sinusoidal waveform template. For the first investigation, a 1D sinusoidal grating with the pitch of 300 nm is used. The repeatability of displacement measurements over a distance of 70 µm is better than 2.2 nm. As the first application, the real-time displacement of a scanning stage is measured by the new encoding principle as it is moved in an open-loop mode and closed-loop mode based on its built-in capacitance sensor

  14. Forces produced by different nonconventional bracket or ligature systems during alignment of apically displaced teeth.

    Science.gov (United States)

    Baccetti, Tiziano; Franchi, Lorenzo; Camporesi, Matteo; Defraia, Efisio; Barbato, Ersilia

    2009-05-01

    To analyze the forces released by four types of passive stainless steel self-ligating brackets (SLBs), and by two nonconventional elastomeric ligature-bracket systems when compared with conventional elastomeric ligatures on conventional stainless steel brackets during the alignment of apically displaced teeth at the maxillary arch. An experimental model consisting of five brackets was used to assess the forces released by the seven different ligature-bracket systems with 0.012'' or 0.014'' superelastic nickel titanium wire in the presence of different amounts of apical displacement of the canine (ranging from 1.5 mm to 6 mm). Comparisons between the different types of bracket/wire/ ligature systems were carried out by means of ANOVA on ranks with Dunnett's post hoc test (P < .05). When correction of a misalignment greater than 3 mm is attempted, a noticeable amount of force for alignment is generated by passive SLBs and nonconventional elastomeric ligature-bracket systems, and a null amount of force is released in the presence of conventional elastomeric ligatures on conventional brackets. When minimal apical displacement is needed (1.5 mm), the differences in performance between low-friction and conventional systems are minimal. These differences become significant when correction of a misalignment of greater than 3.0 mm is attempted.

  15. Force-displacement measurements of earlywood bordered pits using a mesomechanical tester

    Science.gov (United States)

    Samuel L. Zelinka; Keith J. Bourne; John C. Hermanson; Samuel V. Glass; Adriana Costa; Alex C. Wiedenhoeft

    2015-01-01

    The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms, and pit aspiration plays a large role in wood technological applications such as wood drying and preservative treatment. Here we present force–displacement measurements for pit membranes of circular bordered pits, collected on a...

  16. An accurate tangential force-displacement model for granular-flow simulations: Contacting spheres with plastic deformation, force-driven formulation

    International Nuclear Information System (INIS)

    Vu-Quoc, L.; Lesburg, L.; Zhang, X.

    2004-01-01

    An elasto-plastic frictional tangential force-displacement (TFD) model for spheres in contact for accurate and efficient granular-flow simulations is presented in this paper; the present TFD is consistent with the elasto-plastic normal force-displacement (NFD) model presented in [ASME Journal of Applied Mechanics 67 (2) (2000) 363; Proceedings of the Royal Society of London, Series A 455 (1991) (1999) 4013]. The proposed elasto-plastic frictional TFD model is accurate, and is validated against non-linear finite-element analyses involving plastic flows under both loading and unloading conditions. The novelty of the present TFD model lies in (i) the additive decomposition of the elasto-plastic contact area radius into an elastic part and a plastic part, (ii) the correction of the particles' radii at the contact point, and (iii) the correction of the particles' elastic moduli. The correction of the contact-area radius represents an effect of plastic deformation in colliding particles; the correction of the radius of curvature represents a permanent indentation after impact; the correction of the elastic moduli represents a softening of the material due to plastic flow. The construction of both the present elasto-plastic frictional TFD model and its consistent companion, the elasto-plastic NFD model, parallels the formalism of the continuum theory of elasto-plasticity. Both NFD and TFD models form a coherent set of force-displacement (FD) models not available hitherto for granular-flow simulations, and are consistent with the Hertz, Cattaneo, Mindlin, Deresiewicz contact mechanics theory. Together, these FD models will allow for efficient simulations of granular flows (or granular gases) involving a large number of particles

  17. Development of a CMOS MEMS pressure sensor with a mechanical force-displacement transduction structure

    International Nuclear Information System (INIS)

    Cheng, Chao-Lin; Chang, Heng-Chung; Fang, Weileun; Chang, Chun-I

    2015-01-01

    This study presents a capacitive pressure sensor with a mechanical force-displacement transduction structure based on the commercially available standard CMOS process (the TSMC 0.18 μm 1P6M CMOS process). The pressure sensor has a deformable diaphragm to support a movable plate with an embedded sensing electrode. As the diaphragm is deformed by the ambient pressure, the movable plate and its embedded sensing electrode are displaced. Thus, the pressure is detected from the capacitance change between the movable and fixed electrodes. The undeformed movable electrode will increase the effective sensing area between the sensing electrodes, thereby improving the sensitivity. Experimental results show that the proposed pressure sensor with a force-displacement transducer will increase the sensitivity by 126% within the 20 kPa–300 kPa absolute pressure range. Moreover, this study extends the design to add pillars inside the pressure sensor to further increase its sensing area as well as sensitivity. A sensitivity improvement of 117% is also demonstrated for a pressure sensor with an enlarged sensing electrode (the overlap area is increased two fold). (paper)

  18. A curved electrode electrostatic actuator designed for large displacement and force in an underwater environment

    International Nuclear Information System (INIS)

    Preetham, B S; Lake, Melinda A; Hoelzle, David J

    2017-01-01

    There is a need for the development of large displacement ( O (10 −6 ) m) and force ( O (10 −6 ) N) electrostatic actuators with low actuation voltages (<  ±8 V) for underwater bio- MEMS applications. In this paper, we present the design, fabrication, and characterization of a curved electrode electrostatic actuator in a clamped–clamped beam configuration meant to operate in an underwater environment. Our curved electrode actuator is unique in that it operates in a stable manner past the pull-in instability. Models based on the Rayleigh–Ritz method accurately predict the onset of static instability and the displacement versus voltage function, as validated by quasistatic experiments. We demonstrate that the actuator is capable of achieving a large peak-to-peak displacement of 19.5 µ m and force of 43 µ N for a low actuation voltage of less than  ±8 V and is thus appropriate for underwater bio -MEMS applications. (paper)

  19. Characteristics of children with hip displacement in cerebral palsy

    Directory of Open Access Journals (Sweden)

    Wagner Philippe

    2007-10-01

    Full Text Available Abstract Background Hip dislocation in children with cerebral palsy (CP is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme. Methods In a total population of children with CP a standardised clinical and radiological follow-up of the hips was carried out as a part of a hip prevention programme. The present study is based on 212 children followed until 9–16 years of age. Results Of the 212 children, 38 (18% developed displacement with Migration Percentage (MP >40% and further 19 (9% MP between 33 and 39%. Mean age at first registration of hip displacement was 4 years, but some hips showed MP > 40% already at two years of age. The passive range of hip motion at the time of first registration of hip displacement did not differ significantly from the findings in hips without displacement. The risk of hip displacement varied according to CP-subtype, from 0% in children with pure ataxia to 79% in children with spastic tetraplegia. The risk of displacement (MP > 40% was directly related to the level of gross motor function, classified according to the gross motor function classification system, GMFCS, from 0% in children in GMFCS level I to 64% in GMFCS level V. Conclusion Hip displacement in CP often occurs already at 2–3 years of age. Range of motion is a poor indicator of hips at risk. Thus early identification and early radiographic examination of children at risk is of great importance. The risk of hip displacement varies according to both CP-subtype and GMFCS. It is sometimes not possible to determine subtype before 4 years of age, and at present several definitions and classification systems are used. GMFCS is valid and reliable from 2 years of age, and it is internationally accepted. We recommend a hip

  20. Internal displacement in Colombia: Fifteen distinguishing features.

    Science.gov (United States)

    Shultz, James M; Ceballos, Ángela Milena Gómez; Espinel, Zelde; Oliveros, Sofia Rios; Fonseca, Maria Fernanda; Florez, Luis Jorge Hernandez

    2014-01-01

    This commentary aims to delineate the distinguishing features of conflict-induced internal displacement in the nation of Colombia, South America. Even as Colombia is currently implementing a spectrum of legal, social, economic, and health programs for "victims of armed conflict," with particular focus on internally displaced persons (IDPs), the dynamics of forced migration on a mass scale within this country are little known beyond national borders.   The authors of this commentary are embarking on a global mental health research program in Bogota, Colombia to define best practices for reaching the displaced population and implementing sustainable, evidence-based screening and intervention for common mental disorders. Presenting the defining characteristics of internal displacement in Colombia provides the context for our work and, more importantly, conveys the compelling and complex nature of this humanitarian crisis. We attempt to demonstrate Colombia's unique position within the global patterning of internal displacement.

  1. Force and stiffness characteristics of superconducting bearing prototype

    International Nuclear Information System (INIS)

    Matveev, V.; Nizhelskiy, N.; Poluschenko, O.

    2004-01-01

    The radial-axial superconducting bearing prototype was designed, fabricated and tested. The YBaCuO high-temperature superconducting (HTS) monodomain disks diameter 28 mm and thickness of h = 4; 6; 8; 10 mm, capable to trap magnetic field 1 T, were fabricated to be employed in bearing prototype. Force interaction of single field cooled HTS disks with NdFeB magnets depending on disk thickness under 1 mm magnet air gap was studied. It was found that the increase in disk thickness results in reducing radial stiffness and in growing axial one. The results obtained were used for optimization of HTS-PM arrangement, and for developing the bearing design. The designed bearing incorporates a rotor with 7 HTS disks of 4 mm thickness, total mass 90 g, and stator with two pairs of permanent annular magnets of NdFeB. It is established that the force-displacement dependencies of the bearing have three zones: non-hysteresis (elastic) zone with high stiffness up to 560 N/mm; zone of elastic interaction with stiffness 190 N/mm; hysteretic zone with stiffness 150 N/mm in which a rotor residual displacement being observed after unloading. The outer bearing diameter is 130 mm, thickness 30 mm, and mass 1.8 kg. The maximal radial load capacity of the bearing is 190 N at the rotor displacement of 1.3 mm, and the maximal axial load capacity is 85 N at the displacement of 1 mm

  2. Flow Characteristics and Sizing of Annular Seat Valves for Digital Displacement Machines

    DEFF Research Database (Denmark)

    Nørgård, Christian; Bech, Michael Møller; Andersen, Torben O.

    2018-01-01

    operating range. To achieve high machine efficiency, the valve flow losses and the required electrical power needed for valve switching should be low. The annular valve plunger geometry, of a valve prototype developed for digital displacement machines, is parametrized by three parameters: stroke length......This paper investigates the steady-state flow characteristics and power losses of annular seat valves for digital displacement machines. Annular seat valves are promising candidates for active check-valves used in digital displacement fluid power machinery which excels in efficiency in a broad...... a valve prototype. Using the simulated maps to estimate the flow power losses and a simple generic model to estimate the electric power losses, both during digital displacement operation, optimal designs of annular seat valves, with respect to valve power losses, are derived under several different...

  3. KWISP: an ultra-sensitive force sensor for the Dark Energy sector

    CERN Document Server

    Karuza, M; Gardikiotis, A; Hoffmann, D H H; Semertzidis, Y K; Zioutas, K

    2016-01-01

    An ultra-sensitive opto-mechanical force sensor has been built and tested in the optics laboratory at INFN Trieste. Its application to experiments in the Dark Energy sector, such as those for Chameleon-type WISPs, is particularly attractive, as it enables a search for their direct coupling to matter. We present here the main characteristics and the absolute force calibration of the KWISP (Kinetic WISP detection) sensor. It is based on a thin Si3N4 micro-membrane placed inside a Fabry-Perot optical cavity. By monitoring the cavity characteristic frequencies it is possible to detect the tiny membrane displacements caused by an applied force. Far from the mechanical resonant frequency of the membrane, the measured force sensitivity is 5.0e-14 N/sqrt(Hz), corresponding to a displacement sensitivity of 2.5e-15 m/sqrt(Hz), while near resonance the sensitivity is 1.5e-14 N/sqrt(Hz), reaching the estimated thermal limit, or, in terms of displacement, 7.5e-16 N/sqrt(Hz). These displacement sensitivities are comparable...

  4. Low volume, large force (>1mN) and nanometer resolution, electrostatic microactuator for low displacement applications

    NARCIS (Netherlands)

    Sarajlic, Edin; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

    2003-01-01

    A compact electrostatic microactuator suitable for low displacement applications is proposed. The actuator employs a large number of basic units working in parallel together with a built-in mechanical transformation to generate large force. Influence of distinct design parameters on actuator

  5. Tragedia humanitaria del desplazamiento forzado en Colombia The Humanitarian Tragedy of Forced Displacement in Colombia

    Directory of Open Access Journals (Sweden)

    Luis Jorge Garay Salamanca

    2009-07-01

    Full Text Available El artículo presenta un diagnóstico de la situación de la población desplazada en Colombia, a partir de los resultados de la II Encuesta Nacional de Verificación de la Comisión de Seguimiento a la Política Pública sobre Desplazamiento Forzado, realizada en 2008. Factores de vulnerabilidad en materia de salud, educación, seguridad alimentaria, vivienda, informalidad laboral, generación de ingresos, entre otros, revelan una situación de extrema precariedad que está lejos todavía del goce efectivo de derechos por parte de la población en situación de desplazamiento, la cual sintetiza la gravedad de la crisis humanitaria que padece el país.This article presents a diagnosis of the situation of the population of displaced persons in Colombia, from the results of the Second National Verification Survey of the Monitoring Commission of Public Policies on Forced Displacement carried out in 2008. Factors of vulnerability in the areas of health, education, food security, housing, informal labor, generation of incomes, among others, reveal a situation of extreme precariousness that is still far away from the effective enjoyment of rights on the part of populations in situations of forced displacement, which synthesizes the gravity of the humanitarian crisis from which the country suffers.

  6. Analysis of Handling Qualities Design Criteria for Active Inceptor Force-Feel Characteristics

    Science.gov (United States)

    Malpica, Carlos A.; Lusardi, Jeff A.

    2013-01-01

    The force-feel system characteristics of the cyclic inceptors of most helicopters are set based on the characteristics of the mechanical components in the control system (mass, springs, friction dampers, etc.). For these helicopters, the force-feel characteristics typically remain constant over the entire flight envelope, with perhaps a trim release to minimize control forces while maneuvering. With the advent of fly-by-wire control systems and active inceptors in helicopters, the force-feel characteristics are now determined by the closed-loop response of the active inceptor itself as defined by the inertia, force/displacement gradient, damping, breakout force and detent shape configuration parameters in the inceptor control laws. These systems give the flexibility to dynamically prescribe different feel characteristics for different control modes or flight conditions, and the ability to provide tactile cueing to the pilot through the actively controlled side-stick or center-stick cyclic inceptor. For rotorcraft, a few studies have been conducted to assess the effects of cyclic force-feel characteristics on handling qualities in flight. An early study provided valuable insight into the static force-deflection characteristics (force gradient) and the number of axes controlled by the side-stick controller for the U.S. Army's Advanced Digital/Optical Control System (ADOCS) demonstrator aircraft [1]. The first of a series of studies providing insight on the inceptor dynamic force-feel characteristics was conducted on the NASA/Army CH-47B variable-stability helicopter [2]. This work led to a proposed requirement that set boundaries based on the cyclic natural frequency and inertia, with the stipulation of a lower damping ratio limit of 0.3 [3]. A second study was conducted by the Canadian Institute for Aerospace Research using their variable-stability Bell 205A helicopter [4]. This research suggested boundaries for stick dynamics based on natural frequency and damping

  7. 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.

  8. Forces and torques on rigid inclusions in an elastic environment: Resulting matrix-mediated interactions, displacements, and rotations

    Science.gov (United States)

    Puljiz, Mate; Menzel, Andreas M.

    2017-05-01

    Embedding rigid inclusions into elastic matrix materials is a procedure of high practical relevance, for instance, for the fabrication of elastic composite materials. We theoretically analyze the following situation. Rigid spherical inclusions are enclosed by a homogeneous elastic medium under stick boundary conditions. Forces and torques are directly imposed from outside onto the inclusions or are externally induced between them. The inclusions respond to these forces and torques by translations and rotations against the surrounding elastic matrix. This leads to elastic matrix deformations, and in turn results in mutual long-ranged matrix-mediated interactions between the inclusions. Adapting a well-known approach from low-Reynolds-number hydrodynamics, we explicitly calculate the displacements and rotations of the inclusions from the externally imposed or induced forces and torques. Analytical expressions are presented as a function of the inclusion configuration in terms of displaceability and rotateability matrices. The role of the elastic environment is implicitly included in these relations. That is, the resulting expressions allow a calculation of the induced displacements and rotations directly from the inclusion configuration, without having to explicitly determine the deformations of the elastic environment. In contrast to the hydrodynamic case, compressibility of the surrounding medium is readily taken into account. We present the complete derivation based on the underlying equations of linear elasticity theory. In the future, the method will, for example, be helpful to characterize the behavior of externally tunable elastic composite materials, to accelerate numerical approaches, as well as to improve the quantitative interpretation of microrheological results.

  9. Land Restitution and Prevention of Forced Displacement in Colombia

    Directory of Open Access Journals (Sweden)

    Felipe Gómez-Isa

    2010-11-01

    Full Text Available The armed conflict in Colombia, which has generated over three million internally displaced persons, has dramatic humanitarian consequences and raises serious issues regarding the protection of displaced peoples’ rights. The underlying reasons for the displacement often lie in the dynamics associated with territorial control and land seizures undertaken for strategic, military or purely economic purposes. Domestic and international legal provisions have established the victims’ right to the restitution of their homes and property as the “preferred remedy” in cases of displacement. However, policies dealing with displacement, both those of the Colombian government and of several international institutions, fail to take this sufficiently into account. A comprehensive reparation policy for victims must necessarily entail the reversion of lands, territories and goods seized in Colombia under the pretext of the internal armed conflict.

  10. La familia y su reconfiguración a partir del desplazamiento forzado The family and its configuration starting from the forced displacement

    Directory of Open Access Journals (Sweden)

    Gloria Marcela Gómez Builes

    2007-03-01

    Full Text Available Las familias que han llegado a Medellín en situación de desplazamiento forzado por la violencia, constituyen un colectivo humano con características y necesidades particulares. Objetivo: Describir las condiciones de vida de la población en situación de desplazamiento forzado del asentamiento El Palomar, del barrio Bello Oriente, de Medellín, Colombia, en los meses comprendidos entre mayo de 2004 y diciembre de 2005 y las transformaciones de la familia antes y a partir del desplazamiento Metodología: El presente estudio fue realizado desde un enfoque cualitativo, desde la perspectiva de la etnografía focalizada. Resultados: Se destacan los procesos de transformación que sufre la familia en relación con su dinámica y estructura, explicitando los cambios en cuanto a roles, funciones, contextos, posibilidades y limitaciones que se dan a partir del desplazamiento forzado. Conclusiones: La situación de desplazamiento implica la interacción de estas familias con el mundo urbano, que siendo ajeno a sus costumbres y formas de comprender el mundo, se impone y condiciona las posibilidades de desarrollo y realización de las familias y sus integrantes y aumenta la situación de vulnerabilidad, exclusión social y económica, concretándose en la violación del derecho a la familia.The families who have arrived to Medellín under a situation of displacement forced by the violence, constitutes a human group which expresses particular characteristics and needs. Objective: to describe life conditions of the population in forced situation displacement settled in "El palomar", in the district "Bello Oriente" of Medellín between May of 2004-December of 2005, and the changes in the family before and after the displacement. Methodology: The present study was made from a qualitative approach, under the view of focused ethnography. Results: they stand out the process of transformation in the family, according to their dynamic and structures, specifying

  11. [The responsiveness of males having suffered forced displacement regarding their risk of contracting sexually-transmitted infection].

    Science.gov (United States)

    Vásquez-Salazar, Edwin A; Ochoa-Marín, Sandra C; Duarte, María B

    2012-10-01

    Describing displaced males' responsiveness regarding issues concerning sexual and reproductive health, particularly contracting STI/HIV/AIDS. An ethnographic study concerning displaced males who were living in shelters was carried out in Medellín, Colombia, from March to November 2010; observation and semi-structured interview techniques were used. Nineteen men(with and without a partner) aged 18 to 60 years old were interviewed; they had been suffering the effects of forced displacement for less than 1 year. The results were analyzed following grounded theory guidelines. Three main categories were analyzed: having been forcibly displaced and such impact on their daily life, issues related to their sexuality and their ability to respond. Despite forcibly displaced male shaving information about condo muse and perceiving the risk posed by STI/HIV/AIDS, they did not take preventative measures when engaging in their sexual practices and most assumed various risky behavior patterns. Living conditions in the hostel, few job opportunities and the culture regarding machismo increased the risk of acquiring an STI and decreased their responsiveness to them. Responsiveness to STI/HIV/AID Sin males who had been experiencing the hardships of having been recently displaced was seen to have become reduced because of the material and psychosocial conditions which they had to face. Policies and programs addressing this group's specific needs are required which are aimed at improving information regarding sexual and reproductive health, access to services and opportunities for decent work.

  12. Women's rights in the context of forced displacement in Colombia

    Directory of Open Access Journals (Sweden)

    Claudia Lorena Sánchez Lucumí

    2016-03-01

    Full Text Available Throughout this document will explain the significance of displacement and the impact of this on women, since, although it affects more people, this by their vulnerability takes an important role in the war-movement context . Similarly, analyzing the situation through jurisprudence, which consists mainly of sentences guardianship and the remainder in court records, will be mentioned Human Rights that are violated by the active agents of the conflict, and measures will be explained affirmative action has been taken based on this circumstance. Among the important ideas is the fact of social exclusion experienced to get to a place where to put it somehow "belong" and in the second instance, the armed conflict in Colombia is one of the main reasons why they are forced to leave their homes for the purpose of being for themselves and for their children.

  13. Displacement in urban areas: new challenges, new partnerships.

    Science.gov (United States)

    Crisp, Jeff; Morris, Tim; Refstie, Hilde

    2012-07-01

    Rapid urbanisation is a key characteristic of the modern world, interacting with and reinforcing other global mega trends, including armed conflict, climate change, crime, environmental degradation, financial and economic instability, food shortages, underemployment, volatile commodity prices, and weak governance. Displaced people also are affected by and engaged in the process of urbanisation. Increasingly, refugees, returnees, and internally displaced persons (IDPs) are to be found not in camps or among host communities in rural areas, but in the towns and cities of developing and middle-income countries. The arrival and long-term settlement of displaced populations in urban areas needs to be better anticipated, understood, and planned for, with a particular emphasis on the establishment of new partnerships. Humanitarian actors can no longer liaise only with national governments; they must also develop urgently closer working relationships with mayors and municipal authorities, service providers, urban police forces, and, most importantly, the representatives of both displaced and resident communities. This requires linking up with those development actors that have established such partnerships already. © 2012 The Author(s). Journal compilation © Overseas Development Institute, 2012.

  14. Remagnetization effects due to lateral displacement above a PMG on bulk HTS magnet

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Ma, G. T.; Zheng, J.; Ren, J. F.; Li, L. L.; Yang, X. F.; Ye, C. Q.; Wang, S. Y.

    2012-12-01

    For a high-Tc superconducting (HTS) maglev system with large force requirements, the use of magnetized bulk high-Tc superconductor magnets (MBSCMs) is a good candidate because of its strong flux pinning ability and corresponding high trapped flux. Different from the rare-earth permanent magnet (PM), the trapped flux of a MBSCM is sustained by the supercurrent produced by a magnetizing process, so the trapped flux is sensitive to variations of the supercurrent. The lateral displacement of a MBSCM above a PM guideway (PMG) will provide disturbance of the applied field and then alter the supercurrent as a process of remagnetization. Different magnetization histories will bring different remagnetization characteristics and consequently diverse levitation performances for a MBSCM during the lateral displacements. When the MBSCMs are applied into the HTS maglev system, the influence of lateral displacements on levitation performance should be taken into consideration. This article investigates the remagnetization characteristics of a MBSCM when it is subject to the lateral displacements above a PMG with different trapped magnetic flux and opposite magnetization polarities. Relevant analyses about the internal supercurrent configuration based on the critical state model are also included to better understand the remagnetization characteristic of a MBSCM.

  15. A wormlike chain model of forced desorption of a polymer adsorbed on an attractive wall

    International Nuclear Information System (INIS)

    Lam, Pui-Man; Zhen, Yi

    2014-01-01

    Forced desorption of a semiflexible polymer chain on a solid substrate is theoretically investigated. The pulling force versus displacement is studied for varying adsorption energy ε and persistence length P. It is found that the relationships between pulling force and cantilever displacement show a series of characteristic force spikes at different persistence lengths P. These force spikes become more pronounced but the average magnitude of this force decreases as P grows. Our results are of relevance to the forced desorption of DNA on an attractive wall in single-molecule pulling experiments. (paper)

  16. Measurement of the force–displacement response of in vivo human skin under a rich set of deformations

    KAUST Repository

    Flynn, Cormac; Taberner, Andrew; Nielsen, Poul

    2011-01-01

    The non-linear, anisotropic, and viscoelastic properties of human skin vary according to location on the body, age, and individual. The measurement of skin's mechanical properties is important in several fields including medicine, cosmetics, and forensics. In this study, a novel force-sensitive micro-robot applied a rich set of three-dimensional deformations to the skin surface of different areas of the arms of 20 volunteers. The force-displacement response of each area in different directions was measured. All tested areas exhibited a non-linear, viscoelastic, and anisotropic force-displacement response. There was a wide quantitative variation in the stiffness of the response. For the right anterior forearm, the ratio of the maximum probe reaction force to maximum probe displacement ranged from 0.44Nmm-1 to 1.45Nmm-1. All volunteers exhibited similar qualitative anisotropic characteristics. For the anterior right forearm, the stiffest force-displacement response was when the probe displaced along the longitudinal axis of the forearm. The response of the anterior left forearm was stiffest in a direction 20° to the longitudinal axis of the forearm. The posterior upper arm was stiffest in a direction 90° to the longitudinal axis of the arm. The averaged posterior upper arm response was less stiff than the averaged anterior forearm response. The maximum probe force at 1.3mm probe displacement was 0.69N for the posterior upper arm and 1.1N for the right anterior forearm. The average energy loss during the loading-unloading cycle ranged from 11.9% to 34.2%. This data will be very useful for studying the non-linear, anisotropic, and viscoelastic behaviour of skin and also for generating material parameters for appropriate constitutive models. © 2011 IPEM.

  17. Measurement of the force–displacement response of in vivo human skin under a rich set of deformations

    KAUST Repository

    Flynn, Cormac

    2011-06-01

    The non-linear, anisotropic, and viscoelastic properties of human skin vary according to location on the body, age, and individual. The measurement of skin\\'s mechanical properties is important in several fields including medicine, cosmetics, and forensics. In this study, a novel force-sensitive micro-robot applied a rich set of three-dimensional deformations to the skin surface of different areas of the arms of 20 volunteers. The force-displacement response of each area in different directions was measured. All tested areas exhibited a non-linear, viscoelastic, and anisotropic force-displacement response. There was a wide quantitative variation in the stiffness of the response. For the right anterior forearm, the ratio of the maximum probe reaction force to maximum probe displacement ranged from 0.44Nmm-1 to 1.45Nmm-1. All volunteers exhibited similar qualitative anisotropic characteristics. For the anterior right forearm, the stiffest force-displacement response was when the probe displaced along the longitudinal axis of the forearm. The response of the anterior left forearm was stiffest in a direction 20° to the longitudinal axis of the forearm. The posterior upper arm was stiffest in a direction 90° to the longitudinal axis of the arm. The averaged posterior upper arm response was less stiff than the averaged anterior forearm response. The maximum probe force at 1.3mm probe displacement was 0.69N for the posterior upper arm and 1.1N for the right anterior forearm. The average energy loss during the loading-unloading cycle ranged from 11.9% to 34.2%. This data will be very useful for studying the non-linear, anisotropic, and viscoelastic behaviour of skin and also for generating material parameters for appropriate constitutive models. © 2011 IPEM.

  18. Relationships between Isometric Force-Time Characteristics and Dynamic Performance

    Directory of Open Access Journals (Sweden)

    Thomas Dos’Santos

    2017-09-01

    Full Text Available The purpose of this study was to explore the relationships between isometric mid-thigh pull (IMTP force-time characteristics (peak force and time-specific force vales (100–250 ms and dynamic performance and compare dynamic performance between stronger and weaker athletes. Forty-three athletes from different sports (rowing, soccer, bicycle motocross, and hockey performed three trials of the squat jump (SJ, countermovement jump (CMJ, and IMTP, and performed a one repetition maximum power clean (PC. Reactive strength index modified (RSImod was also calculated from the CMJ. Statistically significant large correlations between IMTP force-time characteristics and PC (ρ = 0.569–0.674, p < 0.001, and moderate correlations between IMTP force-time characteristics (excluding force at 100 ms and RSImod (ρ = 0.389–0.449, p = 0.013–0.050 were observed. Only force at 250 ms demonstrated a statistically significant moderate correlation with CMJ height (ρ = 0.346, p = 0.016 and no statistically significant associations were observed between IMTP force-time characteristics and SJ height. Stronger athletes (top 10 demonstrated statistically significantly greater CMJ heights, RSImods, and PCs (p ≤ 0.004, g = 1.32–1.89 compared to weaker (bottom 10 athletes, but no differences in SJ height were observed (p = 0.871, g = 0.06. These findings highlight that the ability to apply rapidly high levels of force in short time intervals is integral for PC, CMJ height, and reactive strength.

  19. 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.

  20. Development of a High Precision Displacement Measurement System by Fusing a Low Cost RTK-GPS Sensor and a Force Feedback Accelerometer for Infrastructure Monitoring.

    Science.gov (United States)

    Koo, Gunhee; Kim, Kiyoung; Chung, Jun Yeon; Choi, Jaemook; Kwon, Nam-Yeol; Kang, Doo-Young; Sohn, Hoon

    2017-11-28

    A displacement measurement system fusing a low cost real-time kinematic global positioning system (RTK-GPS) receiver and a force feedback accelerometer is proposed for infrastructure monitoring. The proposed system is composed of a sensor module, a base module and a computation module. The sensor module consists of a RTK-GPS rover and a force feedback accelerometer, and is installed on a target structure like conventional RTK-GPS sensors. The base module is placed on a rigid ground away from the target structure similar to conventional RTK-GPS bases, and transmits observation messages to the sensor module. Then, the initial acceleration, velocity and displacement responses measured by the sensor module are transmitted to the computation module located at a central monitoring facility. Finally, high precision and high sampling rate displacement, velocity, and acceleration are estimated by fusing the acceleration from the accelerometer, the velocity from the GPS rover, and the displacement from RTK-GPS. Note that the proposed displacement measurement system can measure 3-axis acceleration, velocity as well as displacement in real time. In terms of displacement, the proposed measurement system can estimate dynamic and pseudo-static displacement with a root-mean-square error of 2 mm and a sampling rate of up to 100 Hz. The performance of the proposed system is validated under sinusoidal, random and steady-state vibrations. Field tests were performed on the Yeongjong Grand Bridge and Yi Sun-sin Bridge in Korea, and the Xihoumen Bridge in China to compare the performance of the proposed system with a commercial RTK-GPS sensor and other data fusion techniques.

  1. 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.

  2. Force-Deformation Response of a SMA-Based Actuator Considering the Electric Current Intensity as Step-Input

    Directory of Open Access Journals (Sweden)

    Ion-Cornel Mituletu

    2015-06-01

    Full Text Available The goal of the paper is to accomplish the response regarding the force-displacement characteristic evolution, of a Shape Memory Alloy (SMA actuator element. This reveals the first research stage in controlling the SMA behavior, providing important information about the heating-cooling time intervals. Step excitation of the SMA is performed by few values of electric current intensity, which produces the heating of SMA element up to 90-95 oC. To meet the testing requirements, an adequate test stand has been set up, consisting of sensors for force, displacement and temperature. The analog values provided by sensors were acquired and afterwards analyzed. The values of temperature, displacement and force were achieved, and their characteristic evolution has been performed. Thus, the time intervals are resulted and some other important aspects have been observed, regarding the delay between parameters and the temperature overshoot

  3. Development of a High Precision Displacement Measurement System by Fusing a Low Cost RTK-GPS Sensor and a Force Feedback Accelerometer for Infrastructure Monitoring

    Directory of Open Access Journals (Sweden)

    Gunhee Koo

    2017-11-01

    Full Text Available A displacement measurement system fusing a low cost real-time kinematic global positioning system (RTK-GPS receiver and a force feedback accelerometer is proposed for infrastructure monitoring. The proposed system is composed of a sensor module, a base module and a computation module. The sensor module consists of a RTK-GPS rover and a force feedback accelerometer, and is installed on a target structure like conventional RTK-GPS sensors. The base module is placed on a rigid ground away from the target structure similar to conventional RTK-GPS bases, and transmits observation messages to the sensor module. Then, the initial acceleration, velocity and displacement responses measured by the sensor module are transmitted to the computation module located at a central monitoring facility. Finally, high precision and high sampling rate displacement, velocity, and acceleration are estimated by fusing the acceleration from the accelerometer, the velocity from the GPS rover, and the displacement from RTK-GPS. Note that the proposed displacement measurement system can measure 3-axis acceleration, velocity as well as displacement in real time. In terms of displacement, the proposed measurement system can estimate dynamic and pseudo-static displacement with a root-mean-square error of 2 mm and a sampling rate of up to 100 Hz. The performance of the proposed system is validated under sinusoidal, random and steady-state vibrations. Field tests were performed on the Yeongjong Grand Bridge and Yi Sun-sin Bridge in Korea, and the Xihoumen Bridge in China to compare the performance of the proposed system with a commercial RTK-GPS sensor and other data fusion techniques.

  4. Force characteristics of solenoid electromagnet with ferromagnetic disc in the coil

    International Nuclear Information System (INIS)

    Gueorgiev, Vultchan; Yatchev, Ivan; Alexandrov, Alexander

    2002-01-01

    The paper presents the construction and characteristics of a solenoid electromagnet with ferromagnetic disc placed in the coil. The presence if the disc leads to change of the force characteristic compared with conventional solenoid electromagnets - increasing the force at large air gaps and decreasing the force at small air gaps. This could be very useful for some actuators. It has been studied how the force characteristic depend on disc size, position and material. Finite element method has been used for field and force calculations of the electromagnet. (Author)

  5. Acoustic radiation force control: Pulsating spherical carriers.

    Science.gov (United States)

    Rajabi, Majid; Mojahed, Alireza

    2018-02-01

    The interaction between harmonic plane progressive acoustic beams and a pulsating spherical radiator is studied. The acoustic radiation force function exerted on the spherical body is derived as a function of the incident wave pressure and the monopole vibration characteristics (i.e., amplitude and phase) of the body. Two distinct strategies are presented in order to alter the radiation force effects (i.e., pushing and pulling states) by changing its magnitude and direction. In the first strategy, an incident wave field with known amplitude and phase is considered. It is analytically shown that the zero- radiation force state (i.e., radiation force function cancellation) is achievable for specific pulsation characteristics belong to a frequency-dependent straight line equation in the plane of real-imaginary components (i.e., Nyquist Plane) of prescribed surface displacement. It is illustrated that these characteristic lines divide the mentioned displacement plane into two regions of positive (i.e., pushing) and negative (i.e., pulling) radiation forces. In the second strategy, the zero, negative and positive states of radiation force are obtained through adjusting the incident wave field characteristics (i.e., amplitude and phase) which insonifies the radiator with prescribed pulsation characteristics. It is proved that zero radiation force state occurs for incident wave pressure characteristics belong to specific frequency-dependent circles in Nyquist plane of incident wave pressure. These characteristic circles divide the Nyquist plane into two distinct regions corresponding to positive (out of circles) and negative (in the circles) values of radiation force function. It is analytically shown that the maximum amplitude of negative radiation force is exactly equal to the amplitude of the (positive) radiation force exerted upon the sphere in the passive state, by the same incident field. The developed concepts are much more deepened by considering the required

  6. Predicting the holistic force-displacement relation of the periodontal ligament: in-vitro experiments and finite element analysis

    OpenAIRE

    Chang, Chih-Han; Lei, Yao-Ning; Ho, Yi-Hung; Sung, Yu-Hsing; Lin, Ting-Sheng

    2014-01-01

    Background The biomechanical property of the periodontal ligament (PDL) is important in orthodontics and prosthodontics. The objective of this study was to evaluate the feasibility of measuring the biomechanical behavior of the periodontal ligament using micro-computed tomography (micro-CT). Methods A custom-made apparatus measured the force and displacement of a porcine PDL specimen within the micro-CT environment. Synchronized computed tomography (CT) images were used to obtain the deformat...

  7. The influence of oil leak in modern vehicle shock absorber on its dumping characteristics

    Directory of Open Access Journals (Sweden)

    Rafał BURDZIK

    2009-01-01

    Full Text Available This paper presents results of the modern vehicle shock absorbers’ researches on indicator test stand. On this stand can be determined the diagrams of force versus displacement and force versus velocity. These diagrams can be determined for changeable strokes and constant velocities or the opposite way round. In researches the modern hydraulic twin-tube vehicle shock absorber was modificated and the changes of oil volume were possible. There was determined the influence of oil volume changes on force versus displacement and force versus velocity diagrams. On the basis of force versus velocity diagrams, the dumping characteristics were determined (value of force for maximum velocity on this diagram. The influence of oil volume changes on dumping characteristics was determined too. The results of this investigation can be used in simulation researches of vehicle suspension dynamic.

  8. Effect of two Backpack Designs on Cop Displacement and Plantar Force Distribution in Children during Upright Stance

    Directory of Open Access Journals (Sweden)

    Mastalerz Andrzej

    2016-09-01

    Full Text Available Introduction. Many studies have compared different backpack designs and their influence on the carrier; however, no data referring to school students aged 7-8 years are currently available. Therefore, the aim of the research was to assess the influence of backpack design on centre of pressure (COP displacement and plantar force distribution in children during an upright stance. Material and methods. Nineteen school students (9 males and 10 females volunteered for the study. Two Polish backpacks intended for school use were evaluated: backpack A, which had two main compartments, and backpack B, which had one main compartment. The backpack load was composed of books, binders, and regular school equipment. During the measurements, the subjects were asked to look ahead with the head straight and arms at the sides in a comfortable position and to stand barefoot on the F-Scan® sensors (Tekscan, F-Scan® attached to the force platform (Kistler, carrying a load corresponding to 10% of their body mass. Results. The study found insignificant differences between the two backpack designs. Moreover, COP parameters increased significantly during an upright stance while carrying backpack B in comparison to the empty backpack condition. Additionally, we observed significantly higher values of plantar force distribution in the heel region for the condition without load and insignificantly higher ones for carrying backpack A. Conclusions. The results of the current study suggest that the differences between the two backpack designs are too marginal to be detected through COP displacement. Disturbances in plantar force distribution suggest a lack of posture control and a lower stability of the standing position with a backpack, but these disturbances were significant only when the backpack with one main compartment was used.

  9. Transient Characteristics of Free Piston Vuilleurnier Cycle Heat Pumps

    Science.gov (United States)

    Matsue, Junji; Fujimoto, Norioki; Shirai, Hiroyuki

    A dynamic analysis of a free piston Vuilleumier cycle heat pump was performed using a time-stepping integration method to investigate transient characteristics under power controlling. The nonlinear relationship between displacement and force for pistons was taken into account for the motion of reciprocating components. The force for pistons is mainly caused by the pressure change of working gas varying with piston displacements; moreover nonlinear viscous dissipative force due to the oscillating flow of working gas in heat exchangers and discontinuous damping force caused by solid friction at piston seals and rod seals are included. The displacements of pistons and pressure changes in the Vuilleumier cycle heat pump were integrated by an ideal isothermal thermodynamic relationship. It was assumed that the flow friction was proportional to the kinematic pressure of working gas, and that the solid friction at the seals was due to the functions of the working gas pressure and the tension of seal springs. In order to investigate the transient characteristics of a proposed free piston Vuilleumier cycle heat pump machine when hot-side working gas temperatures and alternate force were changed, some calculations were performed and discussed. These calculation results make clear transient characteristics at starting and power controlling. It was further found that only a small amount of starter power is required in particular conditions. During controlling, the machine becomes unstable when there is ar elatively large reduction in cooling or heating power. Therefore, an auxiliary device is additionally needed to obtain stable operation, such as al inear motor.

  10. The Three Gorges: the unexamined toll of development-induced displacement

    Directory of Open Access Journals (Sweden)

    Martin Stein

    1998-04-01

    Full Text Available In China, the context of forced displacement in its broadest sense centres on four issues: (1 coercive displacement for development; (2 political persecution resulting in controlled displacement; (3 massive labour dislocations; and (4 disaster-induced displacement. This article looks at the role of the state in displacement, focusing on the first of these issues: development-induced displacement.

  11. Force-based and displacement-based reliability assessment approaches for highway bridges under multiple hazard actions

    Directory of Open Access Journals (Sweden)

    Chao Huang

    2015-08-01

    Full Text Available The strength limit state of American Association of State Highway and Transportation Officials (AASHTO Load and Resistance Factor Design (LRFD Bridge Design Specifications is developed based on the failure probabilities of the combination of non-extreme loads. The proposed design limit state equation (DLSE has been fully calibrated for dead load and live load by using the reliability-based approach. On the other hand, most of DLSEs in other limit states, including the extreme events Ⅰ and Ⅱ, have not been developed and calibrated though taking certain probability-based concepts into account. This paper presents an assessment procedure of highway bridge reliabilities under the limit state of extreme event Ⅰ, i. e., the combination of dead load, live load and earthquake load. A force-based approach and a displacement-based approach are proposed and implemented on a set of nine simplified bridge models. Results show that the displacement-based approach comes up with more convergent and accurate reliabilities for selected models, which can be applied to other hazards.

  12. Analysis of the Single Toggle Jaw Crusher Force Transmission Characteristics

    Directory of Open Access Journals (Sweden)

    Moses Frank Oduori

    2016-01-01

    Full Text Available This paper sets out to perform a static force analysis of the single toggle jaw crusher mechanism and to obtain the force transmission characteristics of the mechanism. In order to obtain force transmission metrics that are characteristic of the structure of the mechanism, such influences as friction, dead weight, and inertia are considered to be extraneous and neglected. Equations are obtained by considering the balance of forces at the moving joints and appropriately relating these to the input torque and the output torque. A mechanical advantage, the corresponding transmitted torque, and the variations thereof, during the cycle of motion of the mechanism, are obtained. The mechanical advantage that characterizes the mechanism is calculated as the mean value over the active crushing stroke of the mechanism. The force transmission characteristics can be used as criteria for the comparison of different jaw crusher mechanism designs in order to select the most suitable design for a given application. The equations obtained can also be used in estimating the forces sustained by the components of the mechanism.

  13. A novel platform for in vitro analysis of torque, forces, and three-dimensional file displacements during root canal preparations: application to ProTaper rotary files.

    Science.gov (United States)

    Diop, Amadou; Maurel, Nathalie; Oiknine, Michel; Patoor, Etienne; Machtou, Pierre

    2009-04-01

    We proposed a new testing setup and in vitro experimental procedure allowing the analysis of the forces, torque, and file displacements during the preparation of root canals using nickel-titanium rotary endodontic files. We applied it to the preparation of 20 fresh frozen cadaveric teeth using ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland), according to a clinically used sequence. During the preparations, a clinical hand motion was performed by an endodontist, and we measured the applied torque around the file axis and also the involved three-dimensional forces and 3-dimensional file displacements. Such a biomechanical procedure is useful to better understand the working conditions of the files in terms of loads and displacements. It could be used to analyze the effects of various mechanical and geometric parameters on the files' behavior and to get data for modelling purposes. Finally, it could contribute to studies aiming to improve files design in order to reduce the risks of file fractures.

  14. load-displacement and stability characteristics of tidn-walled beams

    African Journals Online (AJOL)

    construction. Such structural ... The finite displacement formulation is used for load- displacement .... The other stress term, which is the incremental linear stress term a/ is .... formulation, only two out of the four general governing ..... 119, Paper. No. 2700 ... Deformations Spatial Buckling of Thin-Walled Beams and Frames ...

  15. Relationship between friction force and orthodontic force at the leveling stage using a coated wire.

    Science.gov (United States)

    Murayama, Masaki; Namura, Yasuhiro; Tamura, Takahiko; Iwai, Hiroaki; Shimizu, Noriyoshi

    2013-01-01

    The relationship between orthodontic force and friction produced from an archwire and brackets affects the sliding of the wire in the leveling stage. The purpose of this study was to evaluate the relationship between force and friction in a small esthetic nickel-titanium (Ni-Ti) wire. Five esthetic wires (three coated and two plated) and two small, plain Ni-Ti wires (0.012 and 0.014 inches) were used. We performed a three-point bending test according to ISO 15841 and the drawing test with a dental arch model designed with upper linguoversion of the lateral incisor in the arch (displacements of 0.5, 1.0, 2.0 and 3.0 mm), and evaluated the relationship between them. Unloading bending forces of all wires at displacements of less than 1.0 mm were larger than friction forces, but all friction forces at displacements exceeding 2.0 mm were larger than unloading bending forces. The arch likely expands when displacement from the proximal brackets exceeds 1.0 mm. The friction force of a martensite 0.014-inch Ni-Ti wire was significantly greater than those of the other esthetic and austenitic wires. A wire with the smallest possible friction force should be used in cases with more than 1.0 mm displacement.

  16. Characteristics Analysis and Testing of SMA Spring Actuator

    Directory of Open Access Journals (Sweden)

    Jianzuo Ma

    2013-01-01

    Full Text Available The biasing form two-way shape memory alloy (SMA actuator composed of SMA spring and steel spring is analyzed. Based on the force equilibrium equation, the relationship between load capacity of SMA spring and geometric parameters is established. In order to obtain the characteristics of SMA spring actuator, the output force and output displacement of SMA spring under different temperatures are analyzed by the theoretical model and the experimental method. Based on the shape memory effect of SMA, the relationship of the SMA spring actuator's output displacement with the temperature, the stress and strain, the material parameters, and the size parameters is established. The results indicate that the trend of theoretical results is basically consistent with the experimental data. The output displacement of SMA spring actuator is increased with the increasing temperature.

  17. Concurrent Validity of a Portable Force Plate Using Vertical Jump Force-Time Characteristics.

    Science.gov (United States)

    Lake, Jason; Mundy, Peter; Comfort, Paul; McMahon, John J; Suchomel, Timothy J; Carden, Patrick

    2018-05-29

    This study examined concurrent validity of countermovement vertical jump (CMJ) reactive strength index modified and force-time characteristics recorded using a one dimensional portable and laboratory force plate system. Twenty-eight men performed bilateral CMJs on two portable force plates placed on top of two in-ground force plates, both recording vertical ground reaction force at 1000 Hz. Time to take-off, jump height, reactive strength index modified, braking and propulsion impulse, mean net force, and duration were calculated from the vertical force from both force plate systems. Results from both systems were highly correlated (r≥.99). There were small (dbraking impulse, braking mean net force, propulsion impulse, and propulsion mean net force (psystem (95% CL: .9% to 2.5%), indicating very good agreement across all of the dependent variables. The largest limits of agreement belonged to jump height (2.1%), time to take-off (3.4%), and reactive strength index modified (3.8%). The portable force plate system provides a valid method of obtaining reactive strength measures, and several underpinning force-time variables, from unloaded CMJ and practitioners can use both force plates interchangeably.

  18. Characteristics of electromagnetic forces of a single winding EDS MAGLEV system

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Soon Heum [Korea High Speed Rail Construction Authority (Korea, Republic of); Cha, Guee Soo [Seoul National University (Korea, Republic of); Hahn, Song Yop [Soonchunhyang University (Korea, Republic of)

    1995-07-01

    This paper describes the characteristics of electromagnetic forces of Combined superconducting maglev system. Generation of the levitation, the propulsion and the guidance force by a single coil is proved by the phasor analysis. It is also shown that double-layered configuration has better characteristics in efficiency, pulsation of the forces and drag ration than single-layered configuration. (author). 3 refs., 7 figs., 1 tab.

  19. Effect of force tightening on cable tension and displacement in greater trochanter reattachment.

    Science.gov (United States)

    Canet, Fanny; Duke, Kajsa; Bourgeois, Yan; Laflamme, G-Yves; Brailovski, Vladimir; Petit, Yvan

    2011-01-01

    The purpose of this study was to evaluate cable tension during installation, and during loading similar to walking in a cable grip type greater trochanter (GT), reattachment system. A 4th generation Sawbones composite femur with osteotomised GT was reattached with four Cable-Ready® systems (Zimmer, Warsaw, IN). Cables were tightened at 3 different target installation forces (178, 356 and 534 N) and retightened once as recommended by the manufacturer. Cables tension was continuously monitored using in-situ load cells. To simulate walking, a custom frame was used to apply quasi static load on the head of a femoral stem implant (2340 N) and abductor pull (667 N) on the GT. GT displacement (gap and sliding) relative to the femur was measured using a 3D camera system. During installation, a drop in cable tension was observed when tightening subsequent cables: an average 40+12.2% and 11 ± 5.9% tension loss was measured in the first and second cable. Therefore, retightening the cables, as recommended by the manufacturer, is important. During simulated walking, the second cable additionally lost up to 12.2+3.6% of tension. No difference was observed between the GT-femur gaps measured with cables tightened at different installation forces (p=0.32). The GT sliding however was significantly greater (0.9 ± 0.3 mm) when target installation force was set to only 178 N compared to 356 N (0.2 ± 0.1 mm); pcable tightening force should be as close as possible to that recommended by the manufacturer, because reducing it compromises the stability of the GT fragment, whereas increasing it does not improve this stability, but could lead to cable breakage.

  20. Sex Differences in Countermovement Jump Phase Characteristics

    Directory of Open Access Journals (Sweden)

    John J. McMahon

    2017-01-01

    Full Text Available The countermovement jump (CMJ is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH, reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79. Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power, 47%–54% (start of eccentric phase and 85%–100% (latter half of concentric phase, and 65%–87% (bottom of countermovement and initial concentric phase of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off.

  1. 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

  2. Feasibility of novel four degrees of freedom capacitive force sensor for skin interface force

    Directory of Open Access Journals (Sweden)

    Murakami Chisato

    2012-11-01

    Full Text Available Abstract Background The objective of our study was to develop a novel capacitive force sensor that enables simultaneous measurements of yaw torque around the pressure axis and normal force and shear forces at a single point for the purpose of elucidating pressure ulcer pathogenesis and establishing criteria for selection of cushions and mattresses. Methods Two newly developed sensors (approximately 10 mm×10 mm×5 mm (10 and 20 mm×20 mm×5 mm (20 were constructed from silicone gel and four upper and lower electrodes. The upper and lower electrodes had sixteen combinations that had the function as capacitors of parallel plate type. The full scale (FS ranges of force/torque were defined as 0–1.5 N, –0.5-0.5 N and −1.5-1.5 N mm (10 and 0–8.7 N, –2.9-2.9 N and −16.8-16.8 N mm (20 in normal force, shear forces and yaw torque, respectively. The capacitances of sixteen capacitors were measured by an LCR meter (AC1V, 100 kHz when displacements corresponding to four degrees of freedom (DOF forces within FS ranges were applied to the sensor. The measurement was repeated three times in each displacement condition (10 only. Force/torque were calculated by corrected capacitance and were evaluated by comparison to theoretical values and standard normal force measured by an universal tester. Results In measurements of capacitance, the coefficient of variation was 3.23% (10. The Maximum FS errors of estimated force/torque were less than or equal to 10.1 (10 and 16.4% (20, respectively. The standard normal forces were approximately 1.5 (10 and 9.4 N (20 when pressure displacements were 3 (10 and 2 mm (20, respectively. The estimated normal forces were approximately 1.5 (10 and 8.6 N (10 in the same condition. Conclusions In this study, we developed a new four DOF force sensor for measurement of force/torque that occur between the skin and a mattress. In measurement of capacitance, the repeatability was good and it was confirmed that the sensor had

  3. Relationship between friction force and orthodontic force at the leveling stage using a coated wire

    Directory of Open Access Journals (Sweden)

    Masaki MURAYAMA

    2013-12-01

    Full Text Available The relationship between orthodontic force and friction produced from an archwire and brackets affects the sliding of the wire in the leveling stage. Objective: The purpose of this study was to evaluate the relationship between force and friction in a small esthetic nickel-titanium (Ni-Ti wire. Material and Methods: Five esthetic wires (three coated and two plated and two small, plain Ni-Ti wires (0.012 and 0.014 inches were used. We performed a three-point bending test according to ISO 15841 and the drawing test with a dental arch model designed with upper linguoversion of the lateral incisor in the arch (displacements of 0.5, 1.0, 2.0 and 3.0 mm, and evaluated the relationship between them. Results: Unloading bending forces of all wires at displacements of less than 1.0 mm were larger than friction forces, but all friction forces at displacements exceeding 2.0 mm were larger than unloading bending forces. The arch likely expands when displacement from the proximal brackets exceeds 1.0 mm. The friction force of a martensite 0.014-inch Ni-Ti wire was significantly greater than those of the other esthetic and austenitic wires. Conclusions: A wire with the smallest possible friction force should be used in cases with more than 1.0 mm displacement.

  4. 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.

  5. MR imaging characteristics and clinical symptoms related to displaced meniscal flap tears

    Energy Technology Data Exchange (ETDEWEB)

    Lance, Valentin; Heilmeier, Ursula R.; Joseph, Gabby B.; Steinbach, Lynne; Link, Thomas M. [University of California, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Ma, Benjamin [University of California, Department of Orthopedic Surgery and Sports Medicine, San Francisco (United States)

    2014-11-16

    The purpose of our study was (1) to analyze the flap tear location, direction of displacement and size on magnetic resonance (MR) imaging, (2) to describe associated knee abnormalities including presence of effusion, synovitis, bone marrow edema pattern or ligamentous tear, and (3) to assess clinical findings found with flap tears, including the pain score, and determine differences between operative and nonoperative groups. A retrospective radiology database search over the last 3 years identified 238 patients with flap tears, of which ultimately 58 with isolated flap tears were included after exclusion of patients with other significant knee internal derangement, severe degenerative change or prior surgery. MR studies of the knee were analyzed by two radiologists. Imaging characteristics were correlated with associated knee abnormalities and clinical findings. Statistical analysis employed linear and logistic regression models. Inter- and intrareader reliability was calculated. The medial meniscus was the most common site of flap tears (52/60, 87 %), with inferior displacement (47/60, 78 %). The degree of tibial cartilage loss had a positive correlation with the visual analog pain scale (p = 0.03). Patients who underwent arthroscopy were younger than those who did not (p = 0.01) and more likely to have a positive clinical McMurray test (p = 0.01). Medially and inferiorly displaced flap tears are the most common tear pattern. Those undergoing arthroscopy are more likely to have positive meniscal signs on clinical examination. A greater degree of cartilage loss involving the tibia on MR imaging was associated with increasing visual analog pain scores. (orig.)

  6. MR imaging characteristics and clinical symptoms related to displaced meniscal flap tears

    International Nuclear Information System (INIS)

    Lance, Valentin; Heilmeier, Ursula R.; Joseph, Gabby B.; Steinbach, Lynne; Link, Thomas M.; Ma, Benjamin

    2015-01-01

    The purpose of our study was (1) to analyze the flap tear location, direction of displacement and size on magnetic resonance (MR) imaging, (2) to describe associated knee abnormalities including presence of effusion, synovitis, bone marrow edema pattern or ligamentous tear, and (3) to assess clinical findings found with flap tears, including the pain score, and determine differences between operative and nonoperative groups. A retrospective radiology database search over the last 3 years identified 238 patients with flap tears, of which ultimately 58 with isolated flap tears were included after exclusion of patients with other significant knee internal derangement, severe degenerative change or prior surgery. MR studies of the knee were analyzed by two radiologists. Imaging characteristics were correlated with associated knee abnormalities and clinical findings. Statistical analysis employed linear and logistic regression models. Inter- and intrareader reliability was calculated. The medial meniscus was the most common site of flap tears (52/60, 87 %), with inferior displacement (47/60, 78 %). The degree of tibial cartilage loss had a positive correlation with the visual analog pain scale (p = 0.03). Patients who underwent arthroscopy were younger than those who did not (p = 0.01) and more likely to have a positive clinical McMurray test (p = 0.01). Medially and inferiorly displaced flap tears are the most common tear pattern. Those undergoing arthroscopy are more likely to have positive meniscal signs on clinical examination. A greater degree of cartilage loss involving the tibia on MR imaging was associated with increasing visual analog pain scores. (orig.)

  7. Experimental validation of a numerical model of two-phase displacement in porous medium

    International Nuclear Information System (INIS)

    Genty, A.

    1996-01-01

    Burial in geological layers appears to be an interesting solution to dispose of radioactive wastes. This thesis analyzes and simulates the behaviour of gas produced by waste barrels corrosion. The released contaminated gas drains the water initially present in the host rock and yields a water-gas two phase flow. A literature survey of two phase flow shows that fluid interfaces may display instabilities for definite flow characteristics. When the displacement is stable a smooth interface proceeds through the porous medium. When the interface shows fingering, the displacement is said to be 'viscous-unstable', and when the front is jagged the displacement is called 'capillary' displacement. A dimensional analysis of classical equations governing two phase flow in porous media is combined with a classification of dominant forces to define an original map of flow regimes that includes gravitational forces. The map is based on three dimensionless numbers and predicts a priori the flow type. For typical data describing a radioactive waste repository a 'viscous-unstable' displacement is predicted by the map. We simulate water-gas displacement with a numerical model previously developed; this code, based on the Muskat model, uses the mixed-hybrid finite elements technique and is therefore well adapted for tracking moving interfaces. Fluxes are well conserved, however instabilities cannot be simulated. We assume that there is always a scale to be found where instabilities can be averaged and we try to validate the model with experimental two phase flows. We performed laboratory water-gas flow experiments for a variety of flow conditions. The observed displacement types are consistent with the map of flow regimes. Good agreement with numerical simulations is obtained when precise parameters of the displacements are available, in particular relative permeability curves. We conclude that our model allows a first approach of migration of gas near a radioactive waste repository

  8. Forced population displacement | CRDI - Centre de recherches pour ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    28 oct. 2015 ... Increase land and housing tenure for the poor and help displaced communities rebuild the social fabric in their new neighbourhoods. ... The urban poor in Zimbabwe live in extreme stress and anxiety because they are unable to buy or rent property, or meet government requirements to develop their land.

  9. The relationship between the TMJ internal derangement state including rotational displacement and perforation and the clinical characteristics

    International Nuclear Information System (INIS)

    Jeong, Hwan Seok; You Dong Soo

    1998-01-01

    This study was designed to reveal the correlationship between the internal derangement state of TMJ and clinical characteristics including pain and mandibular dysfuntion. One hundred and twenty five subjects with TMJ signs and symptoms were chosen for two years. The level of pain and mandibular dysfuntion were evaluated by Visual Analog Scale (VAS) and Craniomandibular Index (CMI). The diagnostic categories of TMJ internal derangement were determined by arthrography and they included normal disc position, anterior disc displacement with reduction (ADDR), rotational disc displacement with reduction (RDDR), andterior disc displacement without reduction (ADDNR), and rotational disc displacement without reduction (RDDNR). Also disc perforation was used as a criteria to divide the diagnostic subgroups. The obtained results were as follows ; 1. The patient distribution of each group was 5 in normal disc position (4%), 40 in ADDR (32%), 30 in RDDR (24%), 34 in ADDNR (27%), and 16 in RDDNR (13%). 2. Perforation was observed in 8% of ADDR, 10% of RDDR, 32% of ADDNR, and 19% of RDDNR. 3. CMI of perforation group was higher than that of reduction or normal group(p 0.05).

  10. The Displacement of Regimes of Action in the Armed Forces

    DEFF Research Database (Denmark)

    Holsting, Vilhelm Stefan

    The aim of this paper is to explore how one might approach the profession of military command using the concepts of regimes of justification by Luc Boltanski and Laurent Thévenot in an analysis of the contemporary disputes and tensions between political and professional actors and in a time where...... of their contemporary role, responsibility and challenges) and an analysis of the displacement of military regimes in the light of economic and security changes at the societal level. I am arguing that the entrance of new regimes of justification are challenging and displacing the traditional professional justificatory...

  11. The social implications of population displacement and resettlement in the Middle East. Conference report.

    Science.gov (United States)

    Shami, S; Mccann, L

    1993-01-01

    The focus was on a conference on population displacement and resettlement in the Middle East and on brief summaries of 8 papers in the first study group and 9 papers in the second study group. The conference was held at the Institute of Archaeology and Anthropology at the Yarmouk University in Ibid, Jordan, on February 21-24, 1990, and on July 29-31, 1991. Scholars from diverse disciplines gathered to fill a gap in the literature on displacement in the Middle East and to develop a regional theoretical and comparative framework for the study of population movement. A concluding definition of displacement and/or resettlement was determined. The first study group determined that labor or seasonal migration and displacement were both on a continuum with intersecting characteristics, and not divergent. Research should account for the nature, the forcing agents, the underlying causes, the implications, and the outcome of the displacement. The second study group had a more empirical agenda and included the first study group as discussants. The first study group began with a presentation by Dr. Seteney Shami, which reviewed existing literature, outlined unique characteristics for displacement in the Middle East, and discussed the literature on the Nubians, Palestinians, and Bedouins. Other topics included the official settlement of peasants in Iraq and the impact on women and work, the political and economic roles of class among the Palestinian coastal bourgeoisie and other classes, migratory cycles of the Bedouin and disruption by the oil exploration, and historical displacement in Turkey. The second study group focused on migration to the Khartoum area in Sudan among nine unplanned settlements, the two-stage displacement of low-income households from rent-controlled buildings in Cairo and its impact on community structure and employment and social supports, migration from the Suez Canal to Zagazig City in Egypt, displacement due to the Gulf crisis (a case study, the

  12. Athermalization in atomic force microscope based force spectroscopy using matched microstructure coupling.

    Science.gov (United States)

    Torun, H; Finkler, O; Degertekin, F L

    2009-07-01

    The authors describe a method for athermalization in atomic force microscope (AFM) based force spectroscopy applications using microstructures that thermomechanically match the AFM probes. The method uses a setup where the AFM probe is coupled with the matched structure and the displacements of both structures are read out simultaneously. The matched structure displaces with the AFM probe as temperature changes, thus the force applied to the sample can be kept constant without the need for a separate feedback loop for thermal drift compensation, and the differential signal can be used to cancel the shift in zero-force level of the AFM.

  13. Emittance growth rates for displaced beams

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1993-05-01

    Emittance growth rates have been previously analyzed for nonuniform beams in linear channels and for initially uniform mismatched beams in nonlinear channels. These studies were for centered beams. Additional emittance growth can arise in cases where the beam is initially displaced. The purpose of this study is to obtain growth rates for displaced beams. This work differs from studies involving random displacement of electrodes. Our analysis assumes instead that the focusing system is perfectly aligned but that the beam is initially displaced with respect to the equilibrium axis. If the focusing force is slightly nonlinear, we find a gradual transfer of the potential energy of beam displacement into kinetic energy associated with emittance growth. We present explicit results for the emittance growth distance as a function of the nonlinearity of the channel. These results will have practical importance for designers of accelerators and transport systems when setting realistic tolerances for initial beam alignment. These tolerances will depend on the nonlinearity and the length of the system

  14. Atomic displacements in dilute alloys of Cr, Nb and Mo

    Indian Academy of Sciences (India)

    physics pp. 497–514. Atomic displacements in dilute alloys of Cr, Nb and Mo ... used to calculate dynamical matrix and the impurity-induced forces up to second nearest ... origin, the lattice is strained, and the host atoms get displaced to new ...

  15. Displacement and force distribution of splinted and tilted mandibular anterior teeth under occlusal loads: an in silico 3D finite element analysis

    Directory of Open Access Journals (Sweden)

    Allahyar Gerami

    2016-06-01

    Full Text Available Abstract Background Fixed orthodontic retainers have numerous advantages, but it is not known whether they can exert pathological forces on supporting tissues around the splinted teeth. The purpose of this study was to investigate how the inclination of the lower anterior teeth can affect dental displacement and also change the direction of occlusal loads exerted to dental and its supporting tissues. Methods Four three-dimensional finite element models of the anterior part of the mandible were designed. All the models contained the incisors and canines, their periodontal ligament layers (PDLs, the supporting bone (both spongy and cortical, and a pentaflex splinting wire placed in the lingual side of the teeth. Teeth inclination was considered to be 80° (model 1, 90° (model 2, 100° (model 3, and 110° (model 4 to the horizontal plane. The lower incisors were loaded with a 187-N vertical force. Their displacement patterns and the stress in their PDLs were evaluated. Results In incisors with 80° of inclination, less than a 0.1-mm lingual displacement was seen on the incisal edge and a similar distance of displacement towards the labial was seen on their root apices. However, in models with 90°–110° of inclination, the incisal edge displaced labially between about 0.01 and 0.45 mm, while root apices displaced lingually instead. By increasing the angle of the teeth, the strain in the periodontal ligament increased from about 37 to 58 mJ. The von Mises stresses around the cervical and apical areas differed for each tooth and each model, without a similar pattern. Increasing the angle of the teeth resulted in much higher cervical stresses in the incisors, but not in the canines. In the lateral incisor, cervical stress increased until 100° of inclination but reduced to about half by increasing the angle to 110°. Apical stress increased rather consistently in the incisor and lateral incisors, by increasing the inclination. However, in the

  16. Theory of nonaxisymmetric vertical displacement events in tokamaks

    International Nuclear Information System (INIS)

    Fitzpatrick, R.

    2011-01-01

    A semi-analytic sharp-boundary model of a nonaxisymmetric vertical displacement event (VDE) in a large aspect-ratio, high-beta (i.e. β ∼ ε), vertically elongated tokamak plasma is developed. The model is used to simulate nonaxisymmetric VDEs with a wide range of different plasma equilibrium and vacuum vessel parameters. These simulations yield poloidal halo current fractions and toroidal peaking factors whose magnitudes are similar to those seen in experiments, and also reproduce the characteristic inverse scaling between the halo current fraction and the toroidal peaking factor. Moreover, the peak poloidal halo current density in the vacuum vessel is found to correlate strongly with the reciprocal of the minimum edge safety factor attained during the VDE. In addition, under certain circumstances, the ratio of the net sideways force acting on the vacuum vessel to the net vertical force is observed to approach unity. Finally, the peak vertical force per unit area acting on the vessel is found to have a strong correlation with the equilibrium toroidal plasma current at the start of the VDE, but is also found to increase with increasing vacuum vessel resistivity relative to the scrape-off layer plasma.

  17. Evaluation of thermal displacement behavior of high temperature piping system in power-up test of HTTR. No. 1 results up to 20 MW operation

    International Nuclear Information System (INIS)

    Hanawa, Satoshi; Kojima, Takao; Sumita, Junya; Tachibana, Yukio

    2002-03-01

    Temperature of the primary cooling system of the High Temperature Engineering Test Reactor, HTTR, becomes very high because the coolant temperature at the reactor outlet reaches 950degC, and 400degC at inlet of the reactor. Therefore, it is important to confirm the thermal displacement behavior of the high temperature piping system in the primary cooling system from the viewpoint of the structural integrity. Moreover, newly designed 3-dimensional floating support system is adopted to the cooling system, it is meaningful to verify the thermal displacement behavior of the piping system applied the 3-dimensional floating support system. In the power-up test (up to 20 MW operation), thermal displacement behavior of the high temperature piping system was measured. This paper describes the experimental and analytical results of thermal displacement characteristics of the high temperature piping system. The results showed that the resistance force induced from the supporting system effects to the thermal displacement behavior of cooling system, and the analytical results have a good agreement with the experimental results by optimizing the resistant force of the floating support system. Additionally, structural integrity at the 30 MW operation was confirmed by the analysis. (author)

  18. Mechanism of vertical displacement events in JT-60U disruptive discharges

    International Nuclear Information System (INIS)

    Nakamura, Y.; Yoshino, R.; Neyatani, Y.; Tsunematsu, T.; Azumi, M.; Pomphrey, N.; Jardin, S.C.

    1996-01-01

    Enhanced vertical displacement events (VDEs), which are frequently observed in JT-60U disruptive discharges, are investigated using the Tokamak Simulation Code (TSC). The rapid plasma current quench can accelerate the vertical displacement, owing to both the up/down asymmetry of the eddy current distribution arising from the asymmetric geometry of the JT-60U vacuum vessel and the degradation of magnetic field decay index n, leading to high growth rates of positional instability. For a slightly elongated configuration (n = -0.9), the asymmetry of attractive forces on the toroidal plasma plays a dominant role in the VDE mechanism. For a more elongated configuration (n = -1.7), the degradation of field decay index n plays an important role on VDEs, in addition to the effect of asymmetric attractive forces. It is shown that the VDE characteristics of a highly elongated configuration with a rapid plasma current quench can be dominated by the field decay index degradation. It is also pointed out that both the softening of current quenches as was experimentally developed in the JT-60U tokamak, and the optimization of the allowable elongation of the plasma cross-section are critical issues in the development of a general control strategy of discharge termination. (author). 21 refs, 10 figs

  19. Pneumatic tool torque reaction: reaction forces, displacement, muscle activity and discomfort in the hand-arm system.

    Science.gov (United States)

    Kihlberg, S; Kjellberg, A; Lindbeck, L

    1993-06-01

    Reaction forces, hand-arm displacement, muscle activity and discomfort ratings were studied during the securing of threaded fasteners with three angle nutrunners with different shut-off mechanisms, but with the same spindle torque (72-74 Nm). The three tools were tested according to the method specified in ISO 6544. One of the tools had an almost instantaneous shut-off. Another had a more slowly declining torque curve. For the third tool the maximum torque was maintained for a while before shut-off. Twelve male subjects participated in the study. A force platform measured the reaction force between the subject and the floor. The option of the hand-arm system and the shoulder was measured with an optoelectronic measuring system. The muscle activity (EMG) in six muscles in the arm and shoulder was measured with surface electrodes. Significant differences in the arm movements and ground reaction forces were found between the three tools. The smallest values were found with the fast shut-off tool while the delayed shut-off tool caused the largest values. The EMG measures gave inconsistent response patterns. Discomfort ratings were highly correlated with the time for which the tool torque exceeded 90% of peak preset torque, but the time for which the tool torque exceeded 90% of peak calculated by the method specified in ISO 6544. Nutrunners with a shut-off mechanism that causes a slowly decreasing torque or a torque that is maintained for a while before shut-off should be avoided. If no substitutes are available, then a torque reaction bar should be mounted on the tool.

  20. Distal displacement of the maxilla and the upper first molar.

    Science.gov (United States)

    Baumrind, S; Molthen, R; West, E E; Miller, D M

    1979-06-01

    Data from a sample of 198 Class II cases treated with various appliances which deliver distally directed forces to the maxilla were examined to determine the frequency of absolute distal displacement of the upper first molar and of the maxilla. Analysis revealed that such distal displacement is possible and that it is, in fact, a frequent finding following treatment. Long-range stability of distal displacement was not assessed.

  1. Piezoresistive cantilever force-clamp system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Goodman, Miriam B. [Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305 (United States)

    2011-04-15

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  2. In vitro force delivery of nickel-titanium superelastic archwires in vertical displacement

    Directory of Open Access Journals (Sweden)

    Aisha de Souza Gomes Stumpf

    2012-12-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the force delivered by different superlastic nickel-titanium wires during vertical displacement, in order to determine whether their stress release meets the criteria for constant and light forces that are usually accredited to these archwires. METHOD: Ten samples of 6 brands of 0.016-in archwires (Ormco, GAC, Morelli, TP, American Orthodontics e Rocky Mountain were tested in a complete metal model using Dynalock brackets (3M Unitek™. In the canine position, there was a sliding bracket connected to a pole. This set was related to a load cell of 0.5 kg attached to a universal testing machine (Autograph AG-199kNG, Shimadzu. The crosshead speed was 0.5 mm/min and the maximum displacement was 1.0 mm. The model was submerged in temperature-controlled water. The results were analyzed by ANOVA (p OBJETIVO: o objetivo deste estudo foi avaliar a força liberada por diferentes fios de níquel-titânio (NiTi superelástico em deslocamento vertical, a fim de determinar se a liberação de estresse por esses satisfaz o critério de forças suaves e constantes, geralmente atribuído a tais arcos. MÉTODOS: dez amostras de seis arcos de NiTi superelástico 0,016” de marcas comerciais diferentes (Ormco, GAC, Morelli, TP, American Orthodontics e Rocky Mountain foram testados em um modelo metálico usando braquetes Dynalock (3M Unitek. Na região do canino, havia um braquete móvel conectado a uma haste, a qual estava relacionada com uma célula de carga de 0,5kg de uma máquina universal de ensaios (Autograph AG-199kNG, Shimadzu. O deslocamento do conjunto na região do canino foi realizado a uma velocidade constante de 0,5mm/min e o deslocamento máximo foi de 1,0mm. O conjunto foi submerso em água com temperatura controlada a 37ºC. RESULTADOS: os resultados obtidos foram avaliados por ANOVA (p <0,05, usando o software SAS System 8.02, Cry, NC, EUA. O arco da TP apresentou a menor força durante todo o

  3. 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

  4. Resonant forcing of multidimensional chaotic map dynamics.

    Science.gov (United States)

    Foster, Glenn; Hübler, Alfred W; Dahmen, Karin

    2007-03-01

    We study resonances of chaotic map dynamics. We use the calculus of variations to determine the additive forcing function that induces the largest response. We find that resonant forcing functions complement the separation of nearby trajectories, in that the product of the displacement of nearby trajectories and the resonant forcing is a conserved quantity. As a consequence, the resonant function will have the same periodicity as the displacement dynamics, and if the displacement dynamics is irregular, then the resonant forcing function will be irregular as well. Furthermore, we show that resonant forcing functions of chaotic systems decrease exponentially, where the rate equals the negative of the largest Lyapunov exponent of the unperturbed system. We compare the response to optimal forcing with random forcing and find that the optimal forcing is particularly effective if the largest Lyapunov exponent is significantly larger than the other Lyapunov exponents. However, if the largest Lyapunov exponent is much larger than unity, then the optimal forcing decreases rapidly and is only as effective as a single-push forcing.

  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. Spinomotive force induced by a transverse displacement current in a thin metal or doped-semiconductor sheet: Classical and quantum views.

    Science.gov (United States)

    Hu, Chia-Ren

    2004-03-01

    We present classical macroscopic, microscopic, and quantum mechanical arguments to show that in a metallic or electron/hole-doped semiconducting sheet thinner than the screening length, a displacement current applied normal to it can induce a spinomotive force along it. The magnitude is weak but clearly detectable. The classical arguments are purely electromagnetic. The quantum argument, based on the Dirac equation, shows that the predicted effect originates from the spin-orbit interaction, but not of the usual kind. That is, it relies on an external electric field, whereas the usual S-O interaction involves the electric field generated by the ions. Because the Dirac equation incorporatesThomas precession, which is due to relativistic kinematics, the quantum prediction is a factor of two smaller than the classical prediction. Replacing the displacement current by a charge current, and one obtains a new source for the spin-Hall effect. Classical macroscopic argument also predicts its existence, but the other two views are controversial.

  7. X-ray diffraction from ideal mosaic crystals in external fields of certain types. I. Atomic displacements and the corresponding diffraction patterns

    International Nuclear Information System (INIS)

    Treushnikov, E.N.

    2000-01-01

    The problem of the theoretical description of X-ray diffraction from ideal mosaic crystals under the effect of various external fields has been formulated. Electric, magnetic, electromagnetic, and acoustic perturbations are considered. The atomic displacements in crystals under the effect of external fields and the types of the corresponding diffraction patterns are analyzed for various types of perturbations. The crystal classes are determined in which atomic displacements can be recorded experimentally. Diffraction patterns formed under the effect of various external factors are considered on the basis of the derived dependence of the structure factor on the characteristics of an applied force field

  8. Anharmonic 1D actuator model including electrostatic and Casimir forces with fractional damping perturbed by an external force

    Science.gov (United States)

    Mansoori Kermani, Maryam; Dehestani, Maryam

    2018-06-01

    We modeled a one-dimensional actuator including the Casimir and electrostatic forces perturbed by an external force with fractional damping. The movable electrode was assumed to oscillate by an anharmonic elastic force originated from Murrell-Mottram or Lippincott potential. The nonlinear equations have been solved via the Adomian decomposition method. The behavior of the displacement of the electrode from equilibrium position, its velocity and acceleration were described versus time. Also, the changes of the displacement have been investigated according to the frequency of the external force and the voltage of the electrostatic force. The convergence of the Adomian method and the effect of the orders of expansion on the displacement versus time, frequency, and voltage were discussed. The pull-in parameter was obtained and compared with the other models in the literature. This parameter was described versus the equilibrium position and anharmonicity constant.

  9. Anharmonic 1D actuator model including electrostatic and Casimir forces with fractional damping perturbed by an external force

    Science.gov (United States)

    Mansoori Kermani, Maryam; Dehestani, Maryam

    2018-03-01

    We modeled a one-dimensional actuator including the Casimir and electrostatic forces perturbed by an external force with fractional damping. The movable electrode was assumed to oscillate by an anharmonic elastic force originated from Murrell-Mottram or Lippincott potential. The nonlinear equations have been solved via the Adomian decomposition method. The behavior of the displacement of the electrode from equilibrium position, its velocity and acceleration were described versus time. Also, the changes of the displacement have been investigated according to the frequency of the external force and the voltage of the electrostatic force. The convergence of the Adomian method and the effect of the orders of expansion on the displacement versus time, frequency, and voltage were discussed. The pull-in parameter was obtained and compared with the other models in the literature. This parameter was described versus the equilibrium position and anharmonicity constant.

  10. How much vertical displacement of the symphysis indicates instability after pelvic injury?

    Science.gov (United States)

    Golden, Robert D; Kim, Hyunchul; Watson, Jeffrey D; Oliphant, Bryant W; Doro, Christopher; Hsieh, Adam H; Osgood, Greg M; O'Toole, Robert V

    2013-02-01

    Measures of pubic symphyseal widening are used by at least two classification systems as determinants of injury grade. Recent work has challenged the commonly used parameter of 2.5 cm of pubic symphysis as an accurate marker of pelvic injury grade and has suggested a role of rotation in the flexion-extension plane as a determinant of pelvic stability. We investigated pelvic stability in the flexion-extension plane to determine a threshold of rotational displacement of the hemipelvis above which the potential for instability exists. Cadaveric specimens were mounted onto a servohydraulic biaxial testing machine and subjected to a vertically directed flexion moment. Position of hemipelvis was recorded using a three-dimensional motion capture system and video recording. Displacement of the pubic symphysis and changes in length and position of the sacrospinous and sacrotuberous ligaments were recorded. Amount of force applied was measured and recorded. A yield point was determined as the first point at which the force plot exhibited a decrease in force and was correlated to the corresponding displacement. The mean vertical displacement of the pubic symphysis at the yield point was 16 mm (95% confidence interval, 11-22 mm). Mean sacrospinous ligament strain at yield point was 4% (range, 1.0-9.5%). Pelves with vertical rotational symphyseal displacement of less than 11 mm can reasonably be expected to have rotational stability in the flexion-extension plane. Those with displacement of greater than 22 mm can be expected to have lost some integrity regarding resistance to pelvic flexion. These values may allow clinicians to infer pelvic stability from amount of vertical symphyseal displacement.

  11. Large Out-of-Plane Displacement Bistable Electromagnetic Microswitch on a Single Wafer.

    Science.gov (United States)

    Miao, Xiaodan; Dai, Xuhan; Huang, Yi; Ding, Guifu; Zhao, Xiaolin

    2016-05-05

    This paper presents a bistable microswitch fully batch-fabricated on a single glass wafer, comprising of a microactuator, a signal transformer, a microspring and a permanent magnet. The bistable mechanism of the microswitch with large displacement of 160 μm depends on the balance of the magnetic force and elastic force. Both the magnetic force and elastic force were optimized by finite-element simulation to predict the reliable of the device. The prototype was fabricated and characterized. By utilizing thick laminated photoresist sacrificial layer, the large displacement was obtained to ensure the insulation of the microswitch. The testing results show that the microswitch realized the bistable mechanism at a 3-5 V input voltage and closed in 0.96 ms, which verified the simulation.

  12. Disposable soft 3 axis force sensor for biomedical applications.

    Science.gov (United States)

    Chathuranga, Damith Suresh; Zhongkui Wang; Yohan Noh; Nanayakkara, Thrishantha; Hirai, Shinichi

    2015-08-01

    This paper proposes a new disposable soft 3D force sensor that can be used to calculate either force or displacement and vibrations. It uses three Hall Effect sensors orthogonally placed around a cylindrical beam made of silicon rubber. A niobium permanent magnet is inside the silicon. When a force is applied to the end of the cylinder, it is compressed and bent to the opposite side of the force displacing the magnet. This displacement causes change in the magnetic flux around the ratiomatric linear sensors (Hall Effect sensors). By analysing these changes, we calculate the force or displacement in three directions using a lookup table. This sensor can be used in minimal invasive surgery and haptic feedback applications. The cheap construction, bio-compatibility and ease of miniaturization are few advantages of this sensor. The sensor design, and its characterization are presented in this work.

  13. Force characteristics in continuous path controlled crankpin grinding

    Science.gov (United States)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  14. FOREIGN AFFAIRS: Internally Displaced Persons Lack Effective Protection

    National Research Council Canada - National Science Library

    2001-01-01

    Internally displaced persons--those forced to flee their homes because of armed conflict and persecution but who remain within their own country are among the most at-risk, vulnerable populations in the world...

  15. 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

  16. Application of the model of stress postraumático in the study of the impact of the violence on the health mental in displaced population

    Directory of Open Access Journals (Sweden)

    Edgar Gerardo Alejo

    2005-05-01

    Full Text Available The following document pretends to describe the mentalhealth problematic on displaced people, presenting the modelof Post-Traumatic Stress Disorder (PTSD as a possiblediagnose . It includes the characteristics of the experiencesrelated to forced displacement, the previous studies relatedto the assessment of the impact of the stressful experiencesand the need to identify the existing problem in relation tothe psychological impact of the violence presented in thispeople. Thesis in favour and against the application of thePTSD model are discussed and its implications on the studyof the mental health in this population.

  17. Studies on displacement behavior between hydrogen and deuterium in hydride column

    International Nuclear Information System (INIS)

    Lu Guangda; Li Gan; Jiang Guoqiang

    2001-01-01

    A series displacement experiments between hydrogen and deuterium in ZrCo, LaNi 5 , LaNi 4.7 Al 0.3 and Pd hydride column had been conducted at room temperature about. Results indicate that displacement characteristics related to factors such as temperature, gas flow rate, ratio surface area of solid phase and hydrogen isotope separation factor of the metal-hydrogen system. The palladium hydride have the best displacement characteristics, and LaNi 5 , LaNi 4.7 Al 0.3 and ZrCo are in the next places. Theoretical study reveals that the rule of the exchange reaction of hydrogen isotopes in gas-solid interface determines the displacement behavior and the displacing efficiency depends on exchange rate. The ideal stage mode could be used to describe the displacement breakthrough curve. The height equivalent to theoretical place (HETP) indicates the displacing effects. Also, the separation factor has a serious influence to HETP under the same condition

  18. 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.

  19. Development of a Phasor Diagram Creator to Visualize the Piston and Displacer Forces in an Advanced Stirling Convertor

    Science.gov (United States)

    Saha, Dipanjan; Lewandowski, Edward J.

    2013-01-01

    The steady-state, nearly sinusoidal behavior of the components in a free-piston Stirling engine allows for visualization of the forces in the system using phasor diagrams. Based on Newton's second law, F = ma, any phasor diagrams modeling a given component in a system should close if all of the acting forces have been considered. Since the Advanced Stirling Radioisotope Generator (ASRG), currently being developed for future NASA deep space missions, is made up of such nearly sinusoidally oscillating components, its phasor diagrams would also be expected to close. A graphical user interface (GUI) has been written in MATLAB (MathWorks), which takes user input data, passes it to Sage (Gedeon Associates), a one-dimensional thermodynamic modeling program used to model the Stirling convertor, runs Sage, and then automatically plots the phasor diagrams. Using this software tool, the effect of varying different Sage inputs on the phasor diagrams was determined. The parameters varied were piston amplitude, hot-end temperature, cold-end temperature, operating frequency, and displacer spring constant. These phasor diagrams offer useful insight into convertor operation and performance.

  20. 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.

  1. Mixing Characteristics of Strongly-Forced Jet Flames in Crossflow

    Science.gov (United States)

    Marr, Kevin; Clemens, Noel; Ezekoye, Ofodike

    2008-11-01

    The effects of high frequency, large-amplitude forcing on the characteristics of a non-premixed jet flame in crossflow (JFICF) at mean Reynolds numbers of 3,200 and 4,850 are studied experimentally. Harmonic forcing of the jet fuel results in a drastic decrease in flame length and complete suppression of soot luminosity. Visualization by planar laser Mie scattering shows that forced JFICF, similar to forced free or coflow jet flames, are characterized by ejection of high-momentum, deeply penetrating vortical structures. These structures rapidly breakdown and promote intense turbulent mixing in the near region of the jet. The rapid mixing resembles a ``one-step'' process going from a fuel rich state far in the nozzle to a well-mixed, but significantly diluted, state just a few diameters from the jet exit plane. Exhaust gas emissions measurements indicate a decrease in NOx, but increases in CO and unburned hydrocarbons with increasing forcing amplitude. Acetone PLIF measurements are used to investigate the effect of partial-premixing on these emissions findings.

  2. 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...

  3. Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.

    Science.gov (United States)

    Zea, Maria Cecilia; Reisen, Carol A; Bianchi, Fernanda T; Gonzales, Felisa A; Betancourt, Fabián; Aguilar, Marcela; Poppen, Paul J

    2013-01-01

    Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogotá, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogotá. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied.

  4. Displacer Diameter Effect in Displacer Pulse Tube Refrigerator

    Science.gov (United States)

    Zhu, Shaowei

    2017-12-01

    Gas driving displacer pulse tube refrigerators are one of the work recovery type of pulse tube refrigerators whose theoretical efficiency is the same as Stirling refrigerators'. Its cooling power is from the displacement of the displacer. Displace diameter, rod diameter and pressure drop of the regenerator influence the displacement, which are investigated by numerical simulation. It is shown that the displacement ratio of the displacer over the piston is almost not affected by the displacer diameter at the same rod diameter ratio, or displacer with different diameters almost has the same performance.

  5. Optimization of Moving Coil Actuators for Digital Displacement Machines

    DEFF Research Database (Denmark)

    Nørgård, Christian; Bech, Michael Møller; Roemer, Daniel Beck

    2016-01-01

    This paper focuses on deriving an optimal moving coil actuator design, used as force pro-ducing element in hydraulic on/off valves for Digital Displacement machines. Different moving coil actuator geometry topologies (permanent magnet placement and magnetiza-tion direction) are optimized for actu......This paper focuses on deriving an optimal moving coil actuator design, used as force pro-ducing element in hydraulic on/off valves for Digital Displacement machines. Different moving coil actuator geometry topologies (permanent magnet placement and magnetiza-tion direction) are optimized...... for actuating annular seat valves in a digital displacement machine. The optimization objectives are to the minimize the actuator power, the valve flow losses and the height of the actuator. Evaluation of the objective function involves static finite element simulation and simulation of an entire operation...... designs requires approximately 20 W on average and may be realized in 20 mm × Ø 22.5 mm (height × diameter) for a 20 kW pressure chamber. The optimization is carried out using the multi-objective Generalized Differential Evolu-tion optimization algorithm GDE3 which successfully handles constrained multi-objective...

  6. Novel characteristics of traction force in biliary self-expandable metallic stents.

    Science.gov (United States)

    Hori, Yasuki; Hayashi, Kazuki; Yoshida, Michihiro; Naitoh, Itaru; Ban, Tesshin; Miyabe, Katsuyuki; Kondo, Hiromu; Nishi, Yuji; Umemura, Shuichiro; Fujita, Yasuaki; Natsume, Makoto; Kato, Akihisa; Ohara, Hirotaka; Joh, Takashi

    2017-05-01

    In recent years, knowledge concerning the mechanical properties of self-expandable metallic stents (SEMS) has increased. In a previous study, we defined traction force and traction momentum and reported that these characteristics are important for optimal stent deployment. However, traction force and traction momentum were represented as relative values and were not evaluated in various conditions. The purpose of the present study was to measure traction force in various situations assumed during SEMS placement. Traction force and traction momentum were measured in non-stricture, stricture, and angled stricture models using in-house equipment. Stricture and angled stricture models had significantly higher traction force and traction momentum than those of the non-stricture model (stricture vs non-stricture: traction force, 7.2 N vs 1.4 N, P stent influenced the traction force. Clinicians should be aware of the transition of the traction force and should schedule X-ray imaging during SEMS placement. © 2017 Japan Gastroenterological Endoscopy Society.

  7. Single- and multi-frequency detection of surface displacements via scanning probe microscopy.

    Science.gov (United States)

    Romanyuk, Konstantin; Luchkin, Sergey Yu; Ivanov, Maxim; Kalinin, Arseny; Kholkin, Andrei L

    2015-02-01

    Piezoresponse force microscopy (PFM) provides a novel opportunity to detect picometer-level displacements induced by an electric field applied through a conducting tip of an atomic force microscope (AFM). Recently, it was discovered that superb vertical sensitivity provided by PFM is high enough to monitor electric-field-induced ionic displacements in solids, the technique being referred to as electrochemical strain microscopy (ESM). ESM has been implemented only in multi-frequency detection modes such as dual AC resonance tracking (DART) and band excitation, where the response is recorded within a finite frequency range, typically around the first contact resonance. In this paper, we analyze and compare signal-to-noise ratios of the conventional single-frequency method with multi-frequency regimes of measuring surface displacements. Single-frequency detection ESM is demonstrated using a commercial AFM.

  8. 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.

  9. Recent Advances in the Method of Forces: Integrated Force Method of Structural Analysis

    Science.gov (United States)

    Patnaik, Surya N.; Coroneos, Rula M.; Hopkins, Dale A.

    1998-01-01

    Stress that can be induced in an elastic continuum can be determined directly through the simultaneous application of the equilibrium equations and the compatibility conditions. In the literature, this direct stress formulation is referred to as the integrated force method. This method, which uses forces as the primary unknowns, complements the popular equilibrium-based stiffness method, which considers displacements as the unknowns. The integrated force method produces accurate stress, displacement, and frequency results even for modest finite element models. This version of the force method should be developed as an alternative to the stiffness method because the latter method, which has been researched for the past several decades, may have entered its developmental plateau. Stress plays a primary role in the development of aerospace and other products, and its analysis is difficult. Therefore, it is advisable to use both methods to calculate stress and eliminate errors through comparison. This paper examines the role of the integrated force method in analysis, animation and design.

  10. Understanding interferometry for micro-cantilever displacement detection

    Directory of Open Access Journals (Sweden)

    Alexander von Schmidsfeld

    2016-06-01

    Full Text Available Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM operated in ultra-high vacuum is demonstrated for the Michelson and Fabry–Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber–cantilever configurations. In the Fabry–Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz0.5 under optimum conditions.

  11. Opinión de las mujeres desplazadas sobre la repercusión en su salud del desplazamiento forzado Displaced women’s opinion of the impact of forced displacement on their health

    Directory of Open Access Journals (Sweden)

    Amparo Susana Mogollón Pérez

    2006-08-01

    study was carried out by means of semi-structured individual interviews with a maximum variation sample of 25 internally displaced women. A narrative content analysis was conducted with mixed generation of categories and data segmentation by age and themes. The area under study consisted of five localities in the city of Bogotá (Colombia. Results: According to the interviewed women's discourses, their adaptation to city life depended on the new socioeconomic and environmental conditions and the psychosocial impact of displacement on the family. Precarious economic conditions forced them to live in an unhealthy environment and, occasionally, to adopt the role of head of household. In this role, many of these women, particularly young women, faced great difficulties in ensuring that the family's needs were met. Young women and teenagers reported behavioral changes due to displacement, including reproduction of violence in the home. The main self-perceived health problems among displaced women were mental health, access to food, infections and gynecological alterations. Displaced women identified the main factors hindering their access to health services as their economic situation and home responsibilities. Conclusions: Displaced women face new environmental and family challenges that negatively affect their health and access to healthcare. Specific interventions aimed at displaced women are required to foster better health through access to work and long -term socioeconomic stability.

  12. Gender-based violence in conflict and displacement: qualitative findings from displaced women in Colombia.

    Science.gov (United States)

    Wirtz, Andrea L; Pham, Kiemanh; Glass, Nancy; Loochkartt, Saskia; Kidane, Teemar; Cuspoca, Decssy; Rubenstein, Leonard S; Singh, Sonal; Vu, Alexander

    2014-01-01

    Gender-based violence (GBV) is prevalent among, though not specific to, conflict affected populations and related to multifarious levels of vulnerability of conflict and displacement. Colombia has been marked with decades of conflict, with an estimated 5.2 million internally displaced persons (IDPs) and ongoing violence. We conducted qualitative research to understand the contexts of conflict, displacement and dynamics with GBV. This as part of a multi-phase, mixed method study, in collaboration with UNHCR, to develop a screening tool to confidentially identify cases of GBV for referral among IDP women who were survivors of GBV. Qualitative research was used to identify the range of GBV, perpetrators, contexts in conflict and displacement, barriers to reporting and service uptake, as well as to understand experiences of service providers. Thirty-five female IDPs, aged 18 years and older, who self-identified as survivors of GBV were enrolled for in-depth interviews in San Jose de Guaviare and Quibdo, Colombia in June 2012. Thirty-one service providers participated in six focus group discussions and four interviews across these sites. Survivors described a range of GBV across conflict and displacement settings. Armed actors in conflict settings perpetrated threats of violence and harm to family members, child recruitment, and, to a lesser degree, rape and forced abortion. Opportunistic violence, including abduction, rape, and few accounts of trafficking were more commonly reported to occur in the displacement setting, often perpetrated by unknown individuals. Intrafamilial violence, intimate partner violence, including physical and sexual violence and reproductive control were salient across settings and may be exacerbated by conflict and displacement. Barriers to reporting and services seeking were reported by survivors and providers alike. Findings highlight the need for early identification of GBV cases, with emphasis on confidential approaches and active

  13. Blaming the Environment: Ethnic Violence and the Political Economy of Displacement in Kenya

    OpenAIRE

    Kagwanja, Peter

    2002-01-01

    Within the context of historical and political economy, this paper examines the link between environmental stress and the contemporary problems of ethnic violence and forced migrations, specifically internal displacement in Kenya. It examines the various theoretical links to political and ethnic persecution which cause displacement and environmental stress. Examining the historical antecedents of the phenomenon of displacement in Kenya, the paper argues that environmental stress per se cannot...

  14. Forced vibration of nonlinear system with symmetrical piecewise-linear characteristics

    International Nuclear Information System (INIS)

    Watanabe, Takeshi

    1983-01-01

    It is fairly difficult to treat exactly the analysis of a vibrating system including some play because it is accompanied by a strong nonlinear phenomenon of collision. The author attempted the theoretical analysis by the exact solution using series solution and the approximate solution, treating the forced vibration of a system having some play as the forced vibration of a continuous system with nonlinear boundary condition or the colliding vibration of a continuum. In this report, the problem of such system with play is treated as a nonlinear system having the symmetrical, piecewise linear characteristics of one degree of freedom. That is, it is considered that at the time of collision due to play, the collided body causes the deformation accompanied by triangular hystersis elastically and plastically, and the spring characteristics of restitution force change piecewise by the collision. The exact solution using series solution and the approximate solution are performed, and the effectiveness of these theoretical solutions is confirmed by comparing with the solution using an analog computer. The relation between the accuracy of two analysis methods and nonlinear parameters is shown by the examples of numerical calculation. (Kako, I.)

  15. Transformer sound level caused by core magnetostriction and winding stress displacement variation

    Directory of Open Access Journals (Sweden)

    Chang-Hung Hsu

    2017-05-01

    Full Text Available Magnetostriction caused by the exciting variation of the magnetic core and the current conducted by the winding wired to the core has a significant result impact on a power transformer. This paper presents the sound of a factory transformer before on-site delivery for no-load tests. This paper also discusses the winding characteristics from the transformer full-load tests. The simulation and the measurement for several transformers with capacities ranging from 15 to 60 MVA and high voltage 132kV to low voltage 33 kV are performed. This study compares the sound levels for transformers by no-load test (core/magnetostriction and full-load test (winding/displacement ε. The difference between the simulated and the measured sound levels is about 3dB. The results show that the sound level depends on several parameters, including winding displacement, capacity, mass of the core and windings. Comparative results of magnetic induction of cores and the electromagnetic force of windings for no-load and full-load conditions are examined.

  16. Development of a Phasor Diagram Creator to Visualize the Piston and Displacer Forces in an Advanced Stirling Convertor

    Science.gov (United States)

    Saha, Dipanjan; Lewandowski, Edward J.

    2013-01-01

    The steady state, nearly sinusoidal behavior of the components in a Free Piston Stirling Engine allows for visualization of the forces in the system using phasor diagrams. Based on Newton's second law, F=ma, any phasor diagrams modeling a given component in a system should close if all of the acting forces have been considered. Since the Advanced Stirling Radioisotope Generator (ASRG), currently being developed for future NASA deep space missions, is made up of such nearly sinusoidally oscillating components, its phasor diagrams would also be expected to close. A graphical user interface (GUI) has been written in MATLAB by taking user input data, passing it to Sage, a 1-D thermodynamic modeling program used to model the Stirling convertor, running Sage and then automatically plotting the phasor diagrams. Using this software tool, the effect of varying different Sage inputs on the phasor diagrams was determined. The parameters varied were piston amplitude, hot end temperature, cold end temperature, operating frequency, and displacer spring constant. By using these phasor diagrams, better insight can be gained as to why the convertor operates the way that it does.

  17. The analysis of dynamic characteristics and wind-induced displacement response of space Beam String Structure

    Directory of Open Access Journals (Sweden)

    Chen Yong Jian

    2018-01-01

    Full Text Available The Beam String Structure structural system, also called BSS, has the advantages of lighter dead weight and greater flexibility. The wind load is the main design control factor. The dynamic characteristics and wind-induced displacement response of BSS are studied by the finite element method. The roof structure of the stadium roof of the Fuzhou Olympic Sports Center is the engineering background. 1The numerical model was built by ANSYS, by shape finding, determine the initial stress state of structural members such as external cables; 2From the analysis of dynamic characteristics, the main mode of vibration is the vibration of cables; 3The wind speed spectrum of MATLAB generation structure is obtained by AR method, the structural response of the structure under static wind load and fluctuating wind load is calculated. From the analysis result, considering the equivalent static wind load of BSS , the design of adverse wind is not safe, and the fluctuating wind load should be taken into account.

  18. load-displacement and stability characteristics of tidn-walled beams

    African Journals Online (AJOL)

    the mast common of these are the I-shapes, Z-shapes, and the channels. While the I-shaped cross-section beams had received extensive coverage m experimental ... centroid C along the x-axis, while v, and w, represent the displacements of the shear center S in the y- and z- directions, respectively. Also, represents the.

  19. Una mirada empírica a los determinantes del desplazamiento forzado en Colombia An empirical look of tha determinants of forced displacement in Colombia

    Directory of Open Access Journals (Sweden)

    Pérez Murcia Luis Eduardo

    2001-12-01

    Full Text Available Esta investigacion propone un modelo empirico que falsea las distintas hipotesis explicativas sobre los determinantes del desplazamiento forzado. Segun los resultados empiricos no se puede argumentar que los desplazamientos se presentan en los municipios ricos o pobres, pero si se puede argumentar que se producen en zonas con alto potencial economico en donde por la existencia de fuertes mecanismos concentradores del ingreso, baja participacion politica y altos niveles de impunidad, las comunidades viven en condiciones de vulnerabilidad, que van mas alla de la pobreza; el conflicto armado.This research tries to pose an empirical model that denies the
    different alternative hypothesis about the determinants of forced
    displacement in Colombia. According to the empirical results it
    is not correct to state that displacements take place in rich or
    poor counties, but it is correct to argue that displacements take
    place in areas of great economic potential in which, given the
    existence of strong income concentration mechanisms, scarce political participation and high impunity levels, the communities
    live under vulnerable conditions that go beyond poverty; armed conflict.

  20. Flow and Displacement of Non-Newtonian Fluid(Power-Law Model) by Surface Tension and Gravity Force in Inclined Circular Tube

    International Nuclear Information System (INIS)

    Moh, Jeong Hah; Cho, Y. I.

    2014-01-01

    This paper presents the theoretical analysis of a flow driven by surface tension and gravity in an inclined circular tube. A governing equation is developed for describing the displacement of a non-Newtonian fluid(Power-law model) that continuously flows into a circular tube owing to surface tension, which represents a second-order, nonlinear, non-homogeneous, and ordinary differential form. It was found that quantitatively, the theoretical predictions of the governing equation were in excellent agreement with the solutions of the equation for horizontal tubes and the past experimental data. In addition, the predictions compared very well with the results of the force balance equation for steady

  1. Constant Cutting Force Control for CNC Machining Using Dynamic Characteristic-Based Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Hengli Liu

    2015-01-01

    Full Text Available This paper presents a dynamic characteristic-based fuzzy adaptive control algorithm (DCbFACA to avoid the influence of cutting force changing rapidly on the machining stability and precision. The cutting force is indirectly obtained in real time by monitoring and extraction of the motorized spindle current, the feed speed is fuzzy adjusted online, and the current was used as a feedback to control cutting force and maintain the machining process stable. Different from the traditional fuzzy control methods using the experience-based control rules, and according to the complex nonlinear characteristics of CNC machining, the power bond graph method is implemented to describe the dynamic characteristics of process, and then the appropriate variation relations are achieved between current and feed speed, and the control rules are optimized and established based on it. The numerical results indicated that DCbFACA can make the CNC machining process more stable and improve the machining precision.

  2. A simulation technique for 3D MR-guided acoustic radiation force imaging

    International Nuclear Information System (INIS)

    Payne, Allison; Bever, Josh de; Farrer, Alexis; Coats, Brittany; Parker, Dennis L.; Christensen, Douglas A.

    2015-01-01

    Purpose: In magnetic resonance-guided focused ultrasound (MRgFUS) therapies, the in situ characterization of the focal spot location and quality is critical. MR acoustic radiation force imaging (MR-ARFI) is a technique that measures the tissue displacement caused by the radiation force exerted by the ultrasound beam. This work presents a new technique to model the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model. Methods: When a steady-state point-source force acts internally in an infinite homogeneous medium, the displacement of the material in all directions is given by the Somigliana elastostatic tensor. The radiation force field, which is caused by absorption and reflection of the incident ultrasound intensity pattern, will be spatially distributed, and the tensor formulation takes the form of a convolution of a 3D Green’s function with the force field. The dynamic accumulation of MR phase during the ultrasound pulse can be theoretically accounted for through a time-of-arrival weighting of the Green’s function. This theoretical model was evaluated experimentally in gelatin phantoms of varied stiffness (125-, 175-, and 250-bloom). The acoustic and mechanical properties of the phantoms used as parameters of the model were measured using independent techniques. Displacements at focal depths of 30- and 45-mm in the phantoms were measured by a 3D spin echo MR-ARFI segmented-EPI sequence. Results: The simulated displacements agreed with the MR-ARFI measured displacements for all bloom values and focal depths with a normalized RMS difference of 0.055 (range 0.028–0.12). The displacement magnitude decreased and the displacement pattern broadened with increased bloom value for both focal depths, as predicted by the theory. Conclusions: A new technique that models the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model theory has been rigorously validated through comparison

  3. Quantitative measurements of shear displacement using atomic force microscopy

    International Nuclear Information System (INIS)

    Wang, Wenbo; Wu, Weida; Sun, Ying; Zhao, Yonggang

    2016-01-01

    We report a method to quantitatively measure local shear deformation with high sensitivity using atomic force microscopy. The key point is to simultaneously detect both torsional and buckling motions of atomic force microscopy (AFM) cantilevers induced by the lateral piezoelectric response of the sample. This requires the quantitative calibration of torsional and buckling response of AFM. This method is validated by measuring the angular dependence of the in-plane piezoelectric response of a piece of piezoelectric α-quartz. The accurate determination of the amplitude and orientation of the in-plane piezoelectric response, without rotation, would greatly enhance the efficiency of lateral piezoelectric force microscopy.

  4. Displacement in new economy labor markets: Post-displacement wage loss in high tech versus low tech cities.

    Science.gov (United States)

    Davis, Daniel J; Rubin, Beth A

    2016-11-01

    While scholars and politicians tout education as the salve to employment disruptions, we argue that the geography of the new economy, and the social closure mechanisms that geography creates, may be just as important as individuals' characteristics for predicting post-displacement wage loss (or gain). We use data from the 2012 Displaced Workers ement of the Current Population Survey and from the 2010 United States Census to test hypotheses linking local labor markets in different industrial contexts to post-displacement wage loss. Our results point to age as a closure mechanism, and to the partially protective effect of education in high-tech versus low-tech economic sectors. This study is the first to use national level data to examine how employment in high-tech cities influences post-displacement wages. These findings are relevant both for theorizing about the new economy and for public policy. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Prolonged internal displacement and common mental disorders in Sri Lanka: the COMRAID study.

    Science.gov (United States)

    Siriwardhana, Chesmal; Adikari, Anushka; Pannala, Gayani; Siribaddana, Sisira; Abas, Melanie; Sumathipala, Athula; Stewart, Robert

    2013-01-01

    Evidence is lacking on the mental health issues of internally displaced persons, particularly where displacement is prolonged. The COMRAID study was carried out in year 2011 as a comprehensive evaluation of Muslims in North-Western Sri Lanka who had been displaced since 1990 due to conflict, to investigate the prevalence and correlates of common mental disorders. A cross-sectional survey was carried out among a randomly selected sample of internally displaced people who had migrated within last 20 years or were born in displacement. The total sample consisted of 450 adults aged 18-65 years selected from 141 settlements. Common mental disorders (CMDs) and post-traumatic stress disorder (PTSD) prevalences were measured using the Patient Health Questionnaire and CIDI sub-scale respectively. The prevalence of any CMD was 18.8%, and prevalence for subtypes was as follows: somatoform disorder 14.0%, anxiety disorder 1.3%, major depression 5.1%, other depressive syndromes 7.3%. PTSD prevalence was 2.4%. The following factors were significantly associated with CMDs: unemployment (odds ratio 2.8, 95% confidence interval 1.6-4.9), widowed or divorced status (4.9, 2.3-10.1) and food insecurity (1.7, 1.0-2.9). This is the first study investigating the mental health impact of prolonged forced displacement in post-conflict Sri Lanka. Findings add new insight in to mental health issues faced by internally displaced persons in Sri Lanka and globally, highlighting the need to explore broader mental health issues of vulnerable populations affected by forced displacement.

  6. Emotional, physical, and social needs among 0-5-year-old children displaced by the 2010 Chilean earthquake: associated characteristics and exposures.

    Science.gov (United States)

    Arbour, MaryCatherine; Murray, Kara A; Yoshikawa, Hirokazu; Arriet, Felipe; Moraga, Cecilia; Vega, Miguel Angel Cordero

    2017-04-01

    An 8.8-magnitude earthquake occurred off the coast of Chile on 27 February 2010, displacing nearly 2,000 children aged less than five years to emergency housing camps. Nine months later, this study assessed the needs of 140 displaced 0-5-year-old children in six domains: caregiver stability and protection; health; housing; nutrition; psychosocial situation; and stimulation. Multivariate regression was applied to examine the degree to which emotional, physical, and social needs were associated with baseline characteristics and exposure to the earthquake, to stressful events, and to ongoing risks in the proximal post-earthquake context. In each domain, 20 per cent or fewer children had unmet needs. Of all children in the sample, 20 per cent had unmet needs in multiple domains. Children's emotional, physical, and social needs were associated with ongoing exposures amenable to intervention, more than with baseline characteristics or epicentre proximity. Relief efforts should address multiple interrelated domains of child well-being and ongoing risks in post-disaster settings. © 2017 The Author(s). Disasters © Overseas Development Institute, 2017.

  7. Theoretical Design and Characteristics Analysis of a Quasi-Zero Stiffness Isolator Using a Disk Spring as Negative Stiffness Element

    Directory of Open Access Journals (Sweden)

    Lingshuai Meng

    2015-01-01

    Full Text Available This paper presents a novel quasi-zero stiffness (QZS isolator designed by combining a disk spring with a vertical linear spring. The static characteristics of the disk spring and the QZS isolator are investigated. The optimal combination of the configurative parameters is derived to achieve a wide displacement range around the equilibrium position in which the stiffness has a low value and changes slightly. By considering the overloaded or underloaded conditions, the dynamic equations are established for both force and displacement excitations. The frequency response curves (FRCs are obtained by using the harmonic balance method (HBM and confirmed by the numerical simulation. The stability of the steady-state solution is analyzed by applying Floquet theory. The force, absolute displacement, and acceleration transmissibility are defined to evaluate the isolation performance. Effects of the offset displacement, excitation amplitude, and damping ratio on the QZS isolator and the equivalent system (ELS are studied. The results demonstrate that the QZS isolator for overloaded or underloaded can exhibit different stiffness characteristics with changing excitation amplitude. If loaded with an appropriate mass, excited by not too large amplitude, and owned a larger damper, the QZS isolator can possess better isolation performance than its ELS in low frequency range.

  8. Active design method for the static characteristics of a piezoelectric six-axis force/torque sensor.

    Science.gov (United States)

    Liu, Jun; Li, Min; Qin, Lan; Liu, Jingcheng

    2014-01-02

    To address the bottleneck issues of an elastic-style six-axis force/torque sensor (six-axis force sensor), this work proposes a no-elastic piezoelectric six-axis force sensor. The operating principle of the piezoelectric six-axis force sensor is analyzed, and a structural model is constructed. The static-active design theory of the piezoelectric six-axis force sensor is established, including a static analytical/mathematical model and numerical simulation model (finite element model). A piezoelectric six-axis force sensor experimental prototype is developed according to the analytical mathematical model and numerical simulation model, and selected static characteristic parameters (including sensitivity, isotropic degree and cross-coupling) are tested using this model with three approaches. The measured results are in agreement with the analytical results from the static-active design method. Therefore, this study has successfully established a foundation for further research into the piezoelectric multi-axis force sensor and an overall design approach based on static characteristics.

  9. Large scale intender test program to measure sub gouge displacements

    Energy Technology Data Exchange (ETDEWEB)

    Been, Ken; Lopez, Juan [Golder Associates Inc, Houston, TX (United States); Sancio, Rodolfo [MMI Engineering Inc., Houston, TX (United States)

    2011-07-01

    The production of submarine pipelines in an offshore environment covered with ice is very challenging. Several precautions must be taken such as burying the pipelines to protect them from ice movement caused by gouging. The estimation of the subgouge displacements is a key factor in pipeline design for ice gouged environments. This paper investigated a method to measure subgouge displacements. An experimental program was implemented in an open field to produce large scale idealized gouges on engineered soil beds (sand and clay). The horizontal force required to produce the gouge, the subgouge displacements in the soil and the strain imposed by these displacements were monitored on a buried model pipeline. The results showed that for a given keel, the gouge depth was inversely proportional to undrained shear strength in clay. The subgouge displacements measured did not show a relationship with the gouge depth, width or soil density in sand and clay tests.

  10. Lateral restoring force on a magnet levitated above a superconductor

    International Nuclear Information System (INIS)

    Davis, L.C.

    1990-01-01

    The lateral restoring force on a magnet levitated above a superconductor is calculated as a function of displacement from its original position at rest using Bean's critical-state model to describe flux pinning. The force is linear for small displacements and saturates at large displacements. In the absence of edge effects the force always attracts the magnet to its original position. Thus it is a restoring force that contributes to the stability of the levitated magnet. In the case of a thick superconductor slab, the origin of the force is a magnetic dipole layer consisting of positive and negative supercurrents induced on the trailing side of the magnet. The qualitative behavior is consistent with experiments reported to date. Effects due to the finite thickness of the superconductor slab and the granular nature of high-T c materials are also considered

  11. Rapid sampling of stochastic displacements in Brownian dynamics simulations with stresslet constraints

    Science.gov (United States)

    Fiore, Andrew M.; Swan, James W.

    2018-01-01

    Brownian Dynamics simulations are an important tool for modeling the dynamics of soft matter. However, accurate and rapid computations of the hydrodynamic interactions between suspended, microscopic components in a soft material are a significant computational challenge. Here, we present a new method for Brownian dynamics simulations of suspended colloidal scale particles such as colloids, polymers, surfactants, and proteins subject to a particular and important class of hydrodynamic constraints. The total computational cost of the algorithm is practically linear with the number of particles modeled and can be further optimized when the characteristic mass fractal dimension of the suspended particles is known. Specifically, we consider the so-called "stresslet" constraint for which suspended particles resist local deformation. This acts to produce a symmetric force dipole in the fluid and imparts rigidity to the particles. The presented method is an extension of the recently reported positively split formulation for Ewald summation of the Rotne-Prager-Yamakawa mobility tensor to higher order terms in the hydrodynamic scattering series accounting for force dipoles [A. M. Fiore et al., J. Chem. Phys. 146(12), 124116 (2017)]. The hydrodynamic mobility tensor, which is proportional to the covariance of particle Brownian displacements, is constructed as an Ewald sum in a novel way which guarantees that the real-space and wave-space contributions to the sum are independently symmetric and positive-definite for all possible particle configurations. This property of the Ewald sum is leveraged to rapidly sample the Brownian displacements from a superposition of statistically independent processes with the wave-space and real-space contributions as respective covariances. The cost of computing the Brownian displacements in this way is comparable to the cost of computing the deterministic displacements. The addition of a stresslet constraint to the over-damped particle

  12. Effects of constrained arm swing on vertical center of mass displacement during walking.

    Science.gov (United States)

    Yang, Hyung Suk; Atkins, Lee T; Jensen, Daniel B; James, C Roger

    2015-10-01

    The purpose of this study was to determine the effects of constraining arm swing on the vertical displacement of the body's center of mass (COM) during treadmill walking and examine several common gait variables that may account for or mask differences in the body's COM motion with and without arm swing. Participants included 20 healthy individuals (10 male, 10 female; age: 27.8 ± 6.8 years). The body's COM displacement, first and second peak vertical ground reaction forces (VGRFs), and lowest VGRF during mid-stance, peak summed bilateral VGRF, lower extremity sagittal joint angles, stride length, and foot contact time were measured with and without arm swing during walking at 1.34 m/s. The body's COM displacement was greater with the arms constrained (arm swing: 4.1 ± 1.2 cm, arm constrained: 4.9 ± 1.2 cm, p reaction force data indicated that the COM displacement increased in both double limb and single limb stance. However, kinematic patterns visually appeared similar between conditions. Shortened stride length and foot contact time also were observed, although these do not seem to account for the increased COM displacement. However, a change in arm COM acceleration might have contributed to the difference. These findings indicate that a change in arm swing causes differences in vertical COM displacement, which could increase energy expenditure. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. 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 ...

  14. The UN Security Council and prevention of displacement

    Directory of Open Access Journals (Sweden)

    Sanjula Weerasinghe

    2012-12-01

    Full Text Available Respecting the prohibitions against forced and arbitrary displacementcould significantly reduce the risk of, or prevent, displacement insituations of armed conflict, as could insisting on accountabilityfor violations of these prohibitions that amount to war crimes orcrimes against humanity. The UN Security Council has only partiallyaddressed these issues.

  15. Sociodemographic characteristics of the elderly forced migrants in Serbia

    Directory of Open Access Journals (Sweden)

    Lukić Vesna

    2015-01-01

    Full Text Available In the context of the needs and rights of older migrants, migration history is particularly important where the elderly forced migrants are twice as vulnerable. Bearing in mind the intense process of population aging in Serbia which holds the attention of scientists and experts, and the large number of refugees who immigrated in the 90-ies from the former Yugoslav republics, selected sociodemographic structures of the elderly forced migrants in Serbia were analyzed as well as the relevant legal and strategic framework. The aim was to contribute to increasing knowledge of the demographic challenges of this subpopulation of forced migrants, as well as the differences relative to the domicile aging population. The data used in this study included a contingent of forced migrants aged 65 and over, on the basis of additionally processed Census data from 2011, based on questions about the place of birth of the person, year of arrival, the country in which the person lived and the reasons for migration. Hence, the category which is the subject of research, is not defined on the basis of formal refugee status. A comparison of selected sociodemographic characteristics was made in relation to the domicile population, which in the paper means the population of Serbia without forced migrants. The research results indicate that older forced migrants in Serbia have characteristics of the general population of older people in Serbia. Their age gender and marital structures are relatively similar. Most older women are widows who are heads of households, while a significant number are persons with disabilities as well. However, the process of aging of the elderly, present within the local population has not affected forced migrants yet, so this population is to some extent more vital. Data on the economic activity of the elderly forced migrants in Serbia point out to the lack of income as the main problem they are faced with. Older forced migrants are

  16. Torquing an upper central incisor with aligners--acting forces and biomechanical principles.

    Science.gov (United States)

    Hahn, Wolfram; Zapf, Antonia; Dathe, Henning; Fialka-Fricke, Julia; Fricke-Zech, Susanne; Gruber, Rudolf; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

    2010-12-01

    The forces delivered by aligners during torquing have still not been investigated. The purpose of this study was to measure the forces delivered to an upper central incisor during torquing with three different materials of the same thickness, and to describe the biomechanical principles of torquing with aligners. Five identical appliances were manufactured from each of three materials, all with a thickness of 1.0 mm (Ideal Clear®, Erkodur®, and Biolon®). An upper central incisor, as part of the measuring device, was torqued in defined steps in the vestibular and palatal directions with the respective appliance in place. For statistical analysis, the resulting forces, Fx (forces acting in the palatal and facial directions) and Fz (intrusive force as a side-effect) at a displacement of ±0.15 and ±0.8 mm from the tooth at the gingival margin were calculated. The mean Fx forces for ±0.15 mm displacement ranged from -1.89 N [standard deviation (SD) 0.48] to 0.11 N (SD 0.1). The mean Fz forces were between -0.97 N (SD 0.57) and -0.07 N (SD 0.22). The highest intrusive forces were measured during palatal displacement of the measuring tooth. An influence of direction of displacement on the levels of force was observed, especially for Fz at the greater displacement of ±0.8 mm. In relation to the intended amount of root movement during torquing, aligners tend to 'lift up' and therefore no effective force couple can be established for further root control. The force delivery properties are also influenced by the material used and the shape of the tooth.

  17. Biomechanical analysis of the anterior displacement of Tibial tuberosity (Maquet operation: A computer model study

    Directory of Open Access Journals (Sweden)

    Farahmand F

    2000-08-01

    Full Text Available Computer model of the patellofemoral joint was developed and the effects on the anterior displacement of the tibial tuberosity were investigated. The input geometrical and verification data for the model were obtained form an experimental study on a cadaver knee, mounted in an instron machine. The computer program found the configuration of the patellofemoral joint which satified both the geometrical and force equilibrium conditions, simultaneously, using a trial graphical approach.verification of the model was achieved by determining the patellar sagittal plane motion and patellofemoral contact locations and comparing the results with the experimental results of the same specimen and published data. Simulation of the anterior displacement of the tibial tuberosity by the model showed that the location of contact area migrates distally on the femur and proximally on the patella following operation. The contact force of the patellofemoral joint decreased significantly by 70% at full extension, 30% at 30 degrees flexion and around 15% at higher flexion angles for a 1 cm anterior displacement of the tibial tuberosity and nearly doubled for a 2cm anterior displacement. The change of the effective moment are of the quadriceps was not considerable. The results suggest that the major effect of the Maquet operation on the contact force appears in extension and mid-flexion rather than deep flexion amgles. Further displacement of the tuberosity enhances the reduction of the contact force, however, the total reduction is less than what was predicted by Maquet. The change of the contact location relieves pain in short term but causes hyperpressure in the proximal retropatellar surface which might be detrimental in long term

  18. Ouverture mécanique de la molécule d'ADN par micro-manipulation et mesure de force

    Science.gov (United States)

    Bockelmann, Ulrich; Essevaz-Roulet, B.; Thomen, Philippe; Heslot, François

    In this paper we summarize part of our work on the mechanical unzipping of DNA. We have prepared molecular constructions which allow us to attach the two complementary strands of one end of a single DNA molecule of the bacteriophage λ separately to a glass microscope slide and a microscopic bead. In a first series of experiments, a soft microneedle acting as a force sensor is attached to the bead and its deflection is measured with an optical microscope. In a second series, we use an optical trapping interferometer to capture the bead and to measure its displacement to nm resolution. The sample is slowly displaced with respect to the force measurement device, leading to a progressive opening of the double helix. The force measured during this mechanical opening shows a characteristic variation which is related to the base pair sequence of the DNA molecule. To cite this article: U. Bockelmann et al., C. R. Physique 3 (2002) 585-594.

  19. Force and Motion Characteristics of Contamination Particles near the High Voltage End of UHVDC Insulator

    Directory of Open Access Journals (Sweden)

    Lei Lan

    2017-07-01

    Full Text Available It is important to reveal the relations of physical factors to deposition of contaminants on insulator. In this paper, the simulation model of high voltage end of insulator was established to study the force and motion characteristics of particles affected by electric force and airflow drag force near the ultra-high voltage direct current (UHVDC insulator. By finite element method, the electric field was set specially to be similar to the one near practical insulator, the steady fluid field was simulated. The electric force and air drag force were loaded on the uniformly charged particles. The characteristics of the two forces on particles, the relationship between quantity of electric charge on particles and probability of particles contacting the insulator were analyzed. It was found that, near the sheds, airflow drag force on particles is significantly greater than electric force with less electric charge. As the charge multiplies, electric force increases linearly, airflow drag force grows more slowly. There is a trend that the magnitude of electric force and drag force is going to similar. Meanwhile, the probability of particles contacting the insulator is increased too. However, at a certain level of charge which has different value with different airflow velocity, the contact probability has extremum here. After exceeding the value, as the charge increasing, the contact probability decreases gradually.

  20. Lumped impulses, discrete displacements and a moving load analysis

    NARCIS (Netherlands)

    Kok, A.W.M.

    1997-01-01

    Finite element models are usually presented as relations between lumped forces and discrete displacements. Mostly finite element models are found by the elaboration of the method of the virtual work - which is a special case of the Galerkin's variational principle -. By application of Galerkin's

  1. Levitation force of melt-textured YBCO superconductors under non-quasi-static situation

    Science.gov (United States)

    Zhao, Z. M.; Xu, J. M.; Yuan, X. Y.; Zhang, C. P.

    2018-06-01

    The superconducting levitation force of a simple superconductor-magnet system under non-quasi-static situation is investigated experimentally. Two yttrium barium copper oxide (YBCO) samples with different performances are chosen from two small batches of samples prepared by the top-seeded melt-textured growth process. The residual carbon content of the precursor powders of the two batches is different due to different heat treatment processes. During the experimental process for measuring the levitation force, the value of the relative speed between the YBCO sample and the permanent magnet is higher than that in conventional studies. The variation characteristics of the superconducting levitation force are analyzed and a crossing phenomenon in the force-displacement hysteresis curves is observed. The results indicate that the superconducting levitation force is different due to the different residual carbon contents. As residual carbon contents reduce, the crossing phenomenon is more obvious accordingly.

  2. Prosthetic finger phalanges with lifelike skin compliance for low-force social touching interactions

    Directory of Open Access Journals (Sweden)

    Ge Shuzhi

    2011-03-01

    Full Text Available Abstract Background Prosthetic arms and hands that can be controlled by the user's electromyography (EMG signals are emerging. Eventually, these advanced prosthetic devices will be expected to touch and be touched by other people. As realistic as they may look, the currently available prosthetic hands have physical properties that are still far from the characteristics of human skins because they are much stiffer. In this paper, different configurations of synthetic finger phalanges have been investigated for their skin compliance behaviour and have been compared with the phalanges of the human fingers and a phalanx from a commercially available prosthetic hand. Methods Handshake tests were performed to identify which areas on the human hand experience high contact forces. After these areas were determined, experiments were done on selected areas using an indenting probe to obtain the force-displacement curves. Finite element simulations were used to compare the force-displacement results of the synthetic finger phalanx designs with that of the experimental results from the human and prosthetic finger phalanges. The simulation models were used to investigate the effects of (a varying the internal topology of the finger phalanx and (b varying different materials for the internal and external layers. Results and Conclusions During handshake, the high magnitudes of contact forces were observed at the areas where the full grasping enclosure of the other person's hand can be achieved. From these areas, the middle phalanges of the (a little, (b ring, and (c middle fingers were selected. The indentation experiments on these areas showed that a 2 N force corresponds to skin tissue displacements of more than 2 mm. The results from the simulation model show that introducing an open pocket with 2 mm height on the internal structure of synthetic finger phalanges increased the skin compliance of the silicone material to 235% and the polyurethane material to

  3. Determination of electrostatic force and its characteristics based on phase difference by amplitude modulation atomic force microscopy

    Science.gov (United States)

    Wang, Kesheng; Cheng, Jia; Yao, Shiji; Lu, Yijia; Ji, Linhong; Xu, Dengfeng

    2016-12-01

    Electrostatic force measurement at the micro/nano scale is of great significance in science and engineering. In this paper, a reasonable way of applying voltage is put forward by taking an electrostatic chuck in a real integrated circuit manufacturing process as a sample, applying voltage in the probe and the sample electrode, respectively, and comparing the measurement effect of the probe oscillation phase difference by amplitude modulation atomic force microscopy. Based on the phase difference obtained from the experiment, the quantitative dependence of the absolute magnitude of the electrostatic force on the tip-sample distance and applied voltage is established by means of theoretical analysis and numerical simulation. The results show that the varying characteristics of the electrostatic force with the distance and voltage at the micro/nano scale are similar to those at the macroscopic scale. Electrostatic force gradually decays with increasing distance. Electrostatic force is basically proportional to the square of applied voltage. Meanwhile, the applicable conditions of the above laws are discussed. In addition, a comparison of the results in this paper with the results of the energy dissipation method shows the two are consistent in general. The error decreases with increasing distance, and the effect of voltage on the error is small.

  4. Neutron diffraction determination of atomic mean-square displacements in cubic compounds of Ni-Al and Ni-Al-Cu systems

    International Nuclear Information System (INIS)

    Khidirov, I.; Mukhtarova, N.N.

    2002-01-01

    The atomic mean-square displacements (AMSD) are some of important characteristics of the solid and can be the main information for determination of a number of other characteristics of substances. In the work AMSD is determined for a number of cubic compounds of Ni-Al, Ni-Al-Cu systems immediately from intensities of neutron diffraction maxima. It is shown by the offered method that in all NiAl x and NiAlCu x compounds with the CsCl - type structure AMSD are near each other and they are practically constant. Therefore it is possible to assume that within the homogeneity region of these compounds the interatomic bond forces are changed insignificantly

  5. Job Displacement and First Birth Over the Business Cycle.

    Science.gov (United States)

    Hofmann, Barbara; Kreyenfeld, Michaela; Uhlendorff, Arne

    2017-06-01

    In this article, we investigate the impact of job displacement on women's first-birth rates as well as the variation in this effect over the business cycle. We use mass layoffs to estimate the causal effects of involuntary job loss on fertility in the short and medium term, up to five years after displacement. Our analysis is based on rich administrative data from Germany, with an observation period spanning more than 20 years. We apply inverse probability weighting (IPW) to flexibly control for the observed differences between women who were and were not displaced. To account for the differences in the composition of the women who were displaced in a downturn and the women who were displaced in an upswing, we use a double weighting estimator. Results show that the extent to which job displacement has adverse effects on fertility depends on the business cycle. The first-birth rates were much lower for women who were displaced in an economic downturn than for those who lost a job in an economic upturn. This result cannot be explained by changes in the observed characteristics of the displaced women over the business cycle.

  6. Monitoring Method of Cutting Force by Using Additional Spindle Sensors

    Science.gov (United States)

    Sarhan, Ahmed Aly Diaa; Matsubara, Atsushi; Sugihara, Motoyuki; Saraie, Hidenori; Ibaraki, Soichi; Kakino, Yoshiaki

    This paper describes a monitoring method of cutting forces for end milling process by using displacement sensors. Four eddy-current displacement sensors are installed on the spindle housing of a machining center so that they can detect the radial motion of the rotating spindle. Thermocouples are also attached to the spindle structure in order to examine the thermal effect in the displacement sensing. The change in the spindle stiffness due to the spindle temperature and the speed is investigated as well. Finally, the estimation performance of cutting forces using the spindle displacement sensors is experimentally investigated by machining tests on carbon steel in end milling operations under different cutting conditions. It is found that the monitoring errors are attributable to the thermal displacement of the spindle, the time lag of the sensing system, and the modeling error of the spindle stiffness. It is also shown that the root mean square errors between estimated and measured amplitudes of cutting forces are reduced to be less than 20N with proper selection of the linear stiffness.

  7. Forced displacement and adaptation in the destination context: The case of Barranquilla

    Directory of Open Access Journals (Sweden)

    Ignacio Ramos Vidal

    2017-11-01

    Full Text Available In this article we analyze the impact that displacement could generate on: a the displaced’ social support network structure; b employment, and c community involvement variables. A comparative study in which are interviewed 62 people living in two low-income areas in Barranquilla city (Colombia is developed. Half of respondents are displaced. Egocentric network analysis evidenced that people who have a job presents networks geographically diversified. The population interviewed has dense networks in which there is a high overlapping degree. Regarding community involvement indicators, is observed that time of residence is a key factor facilitating the process of identification with the community, and the involvement on participatory activities. Cluster analysis is used to identify two different groups according to 1 the income level, 2 the time who haveresided in the destination community and 3 the number of family members with whom they live.

  8. A CMOS-MEMS clamped–clamped beam displacement amplifier for resonant switch applications

    Science.gov (United States)

    Liu, Jia-Ren; Lu, Shih-Chuan; Tsai, Chun-Pu; Li, Wei-Chang

    2018-06-01

    This paper presents a micromechanical clamped–clamped beam (CC-beam) displacement amplifier based on a CMOS-MEMS fabrication process platform. In particular, a 2.0 MHz resonant displacement amplifier composed of two identical CC-beams coupled by a mechanical beam at locations where the two beams have mismatched velocities exhibits a larger displacement, up to 9.96×, on one beam than that of the other. The displacement amplification prevents unwanted input impacting—the structure switches only to the output but not the input—required by resonant switch-based mechanical circuits (Kim et al 2009 22nd IEEE Int. Conf. on Micro Electro Mechanical Systems; Lin et al 2009 15th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’09) Li et al 2013 17th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’13)). Compared to a single CC-beam displacement amplifier, theory predicts that the displacement amplifying CC-beam array yields a larger overall output displacement for displacement gain beyond 1.13 thanks to the preserved input driving force. A complete analytical model predicts the resultant stiffness and displacement gain of the coupled CC-beam displacement amplifier that match well with finite element analysis (FEA) prediction and measured results.

  9. Characteristics of Bone Injuries Resulting from Knife Wounds Incised with Different Forces.

    Science.gov (United States)

    Humphrey, Caitlin; Kumaratilake, Jaliya; Henneberg, Maciej

    2017-11-01

    The aim of this research was to experimentally determine the characteristics of incised bone wounds, which are commonly found in defense injuries. A specially constructed pivoting arm device was used to inflict wounds with controlled forces and direction. Five knives were selected to inflict the wounds on porcine forelimbs. Eight incised wounds were made per knife per force. A larger knife and a greater force caused longer and wider bone wounds. Comparisons of individual knives at the two forces produced varying results in the bone wounds. A correlation was seen between the force and the length (r = 0.69), width (r = 0.63), and depth (r = 0.57) of bone wounds. Serrated-edge and nonserrated knives can be distinguished from the appearance of the wound. The outcomes may be applicable in forensic investigations to ascertain the forces associated with incised wounds and identify the specific knife used. © 2017 American Academy of Forensic Sciences.

  10. Levitation and lateral forces between a point magnetic dipole and a superconducting sphere

    International Nuclear Information System (INIS)

    Al-Khateeb, H M; Alqadi, M K; Alzoubi, F Y; Albiss, B; Hasan, M K; Ayoub, N Y

    2016-01-01

    The dipole–dipole interaction model is employed to investigate the angular dependence of the levitation and lateral forces acting on a small magnet in an anti-symmetric magnet/superconducting sphere system. Breaking the symmetry of the system enables us to study the lateral force which is important in the stability of the magnet above a superconducting sphere in the Meissner state. Under the assumption that the lateral displacement of the magnet is small compared to the physical dimensions of our proposed system, analytical expressions are obtained for the levitation and lateral forces as a function of the geometrical parameters of the superconductor as well as the height, the lateral displacement, and the orientation of the magnetic moment of the magnet. The dependence of the levitation force on the height of the levitating magnet is similar to that in the symmetric magnet/superconducting sphere system within the range of proposed lateral displacements. It is found that the levitation force is linearly dependent on the lateral displacement whereas the lateral force is independent of this displacement. A sinusoidal variation of both forces as a function of the polar and azimuthal angles specifying the orientation of the magnetic moment is observed. The relationship between the stability and the orientation of the magnetic moment is discussed for different orientations. (paper)

  11. Current Density and Plasma Displacement Near Perturbed Rational Surface

    International Nuclear Information System (INIS)

    Boozer, A.H.; Pomphrey, N.

    2010-01-01

    The current density in the vicinity of a rational surface of a force-free magnetic field subjected to an ideal perturbation is shown to be the sum of both a smooth and a delta-function distribution, which give comparable currents. The maximum perturbation to the smooth current density is comparable to a typical equilibrium current density and the width of the layer in which the current flows is shown to be proportional to the perturbation amplitude. In the standard linearized theory, the plasma displacement has an unphysical jump across the rational surface, but the full theory gives a continuous displacement.

  12. Achilles tendinopathy modulates force frequency characteristics of eccentric exercise.

    Science.gov (United States)

    Grigg, Nicole L; Wearing, Scott C; O'Toole, John M; Smeathers, James E

    2013-03-01

    Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.

  13. Normal dynamic deformation characteristics of non-consecutive jointed rock masses under impact loads

    Science.gov (United States)

    Zeng, Sheng; Jiang, Bowei; Sun, Bing

    2017-08-01

    In order to study deformation characteristics of non-consecutive single jointed rock masses under impact loads, we used the cement mortar materials to make simulative jointed rock mass samples, and tested the samples under impact loads by the drop hammer. Through analyzing the time-history signal of the force and the displacement, first we find that the dynamic compression displacement of the jointed rock mass is significantly larger than that of the intact jointless rock mass, the compression displacement is positively correlated with the joint length and the impact height. Secondly, the vertical compressive displacement of the jointed rock mass is mainly due to the closure of opening joints under small impact loads. Finally, the peak intensity of the intact rock mass is larger than that of the non-consecutive jointed rock mass and negatively correlated with the joint length under the same impact energy.

  14. Fabrication and characterization of wide band AE sensors for quantitative detection of displacement and velocity

    International Nuclear Information System (INIS)

    Kim, Byung G.; Kim, Young Hwan

    1992-01-01

    Acoustic emission sensors to show a flat response for displacement and velocity of a specimen surface in a wide frequency were fabricated. The sensors were conical sensors employing conical type piezoelectric elements and a PVDF sensor employing PVDF piezoelctric polymer. The transient outputs of the sensors due to step-like forces and their sensitivity spectrum were measured. The results were compared with the theoretical displacement and velocity signals calculated using Green's function and a simulated ramp force. The sensor outputs and the theoretical signals were consistent with each other. The sensors showed flat sensitivity spectra in the wide frequency range. The present work showed that conical PZT sensors are suited for the direct measurement of vertical displacement, and PVDF sensors for that of the vertical velocity of a plate surface.

  15. Robust approach to maximize the range and accuracy of force application in atomic force microscopes with nonlinear position-sensitive detectors

    International Nuclear Information System (INIS)

    Silva, E C C M; Vliet, K J van

    2006-01-01

    The atomic force microscope is used increasingly to investigate the mechanical properties of materials via sample displacement under an applied force. However, both the extent of forces attainable and the accuracy of those forces measurements are significantly limited by the optical lever configuration that is commonly used to infer nanoscale deflection of the cantilever. We present a robust and general approach to characterize and compensate for the nonlinearity of the position-sensitive optical device via data processing, requiring no modification of existing instrumentation. We demonstrate that application of this approach reduced the maximum systematic error on the gradient of a force-displacement response from 50% to 5%, and doubled the calibrated force application range. Finally, we outline an experimental protocol that optimizes the use of the quasi-linear range of the most commonly available optical feedback configurations and also accounts for the residual systematic error, allowing the user to benefit from the full detection range of these indirect force sensors

  16. Displacive stability of a void in a void lattice

    International Nuclear Information System (INIS)

    Brailsford, A.D.

    1977-01-01

    It has recently been suggested that the stability of the void-lattice structure in irradiated metals may be attributed to the effect of the overlapping of the point-defect diffusion fields associated with each void. It is shown here, however, that the effect is much too weak. When one void is displaced from its lattice site, the displacement is shown to relax to zero as proposed, but a conservative estimate indicates that the characteristic time is equivalent to an irradiation dose of the order of 300 displacements per atom which is generally much greater than the dose necessary for void-lattice formation

  17. Cervical spine mobilisation forces applied by physiotherapy students.

    Science.gov (United States)

    Snodgrass, Suzanne J; Rivett, Darren A; Robertson, Val J; Stojanovski, Elizabeth

    2010-06-01

    Postero-anterior (PA) mobilisation is commonly used in cervical spine treatment and included in physiotherapy curricula. The manual forces that students apply while learning cervical mobilisation are not known. Quantifying these forces informs the development of strategies for learning to apply cervical mobilisation effectively and safely. This study describes the mechanical properties of cervical PA mobilisation techniques applied by students, and investigates factors associated with force application. Physiotherapy students (n=120) mobilised one of 32 asymptomatic subjects. Students applied Grades I to IV central and unilateral PA mobilisation to C2 and C7 of one asymptomatic subject. Manual forces were measured in three directions using an instrumented treatment table. Spinal stiffness of mobilised subjects was measured at C2 and C7 using a device that applied a standard oscillating force while measuring this force and its concurrent displacement. Analysis of variance was used to determine differences between techniques and grades, intraclass correlation coefficients (ICC) were used to calculate the inter- and intrastudent repeatability of forces, and linear regression was used to determine the associations between applied forces and characteristics of students and mobilised subjects. Mobilisation forces increased from Grades I to IV (highest mean peak force, Grade IV C7 central PA technique: 63.7N). Interstudent reliability was poor [ICC(2,1)=0.23, 95% confidence interval (CI) 0.14 to 0.43], but intrastudent repeatability of forces was somewhat better (0.83, 95% CI 0.81 to 0.86). Higher applied force was associated with greater C7 stiffness, increased frequency of thumb pain, male gender of the student or mobilised subject, and a student being earlier in their learning process. Lower forces were associated with greater C2 stiffness. This study describes the cervical mobilisation forces applied by students, and the characteristics of the student and mobilised

  18. WOMEN AND CHILDRENS, THE MAIN VICTIMS OF FORCED DISPLACEMENT

    Directory of Open Access Journals (Sweden)

    José Alonso Andrade Salazar

    2010-07-01

    Full Text Available This paper aims to shows the particular manner as in Colombia, women and children areparticularly vulnerable by armed groups that attack their dignity and privacy affect their family, ideological and sexual. The preparation of the article involved an extensive literature review. In Colombia and adolescent girls constitute 53% of the displaced population, of which at least 17% were mobilized as a result of harassment, assault and sexual violence. The vital risk factors and vulnerability are directly proportional to the armed conflict, therefore the war dissociates the family unit, and alters the elements of group cohesion. Often children carry their emotional state through aggressive or playful - in conflicting attitudes, and recharges in women full weight of family reconstitution, which hinders its adaptation process.

  19. Oil Stiction in Fast Switching Annular Seat Valves for Digital Displacement Fluid Power Machines

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.

    2014-01-01

    Digital Displacement (DD) fluid power machines utilizes electronically controlled seat valves connected to pressure chambers to obtain variable displacement with high operational efficiency and high bandwidth. To achieve high efficiency, fast valve switching is essential and all aspects related...... to the dynamic behaviour of the seat valves must be considered to optimize the machine efficiency. A significant effect influencing the valves switching performance is the presence of oil stiction when separating the contact surfaces in valve opening movement. This oil stiction force is limited by cavitation...... for low pressure levels, e.g. valves connected to the low pressure manifold, however for valves operated at higher pressure levels, the oil stiction force is dominating when the separating surfaces are close to contact. This paper presents an analytic solution to the oil stiction force for annular seat...

  20. 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...

  1. Refugiados y desplazados forzados: Categorías de la migración forzada creadas como medidas de contención a las migraciones no deseadas Refugees and Displaced Persons: Categories of Forced Migration Created as Means to Contain Unwanted Migration

    Directory of Open Access Journals (Sweden)

    Paola Andrea Posada

    2009-07-01

    Full Text Available En este artículo se pretende exponer el modo en que los refugiados y los desplazados forzados surgen como categorías jurídicas, a partir de intereses de la comunidad internacional por controlar las migraciones no deseadas. Para ello se hace un desarrollo analítico a partir del Sistema global de las migraciones propuesto por Vidal (2005, en el cual se relacionan las categorías de migración forzada, refugio y desplazamiento forzado. Se intenta, además, mostrar que la categoría de refugiado incide de manera restrictiva en los intereses de los migrantes forzados y entre ellos los desplazados forzados.This article aims to present the way in which the legal categories of "refugees" and "displaced persons" arise from the interest of the international community to control unwanted migration. In order to do so, an analytical argument is used based on the global system of migration proposed by Vidal (2005, in which the categories of forced migration, refugee and forced displacement are related. The article also tries to show that the category of refugee impacts in a restrictive way the interests of forced migrants, including displaced persons.

  2. Coulomb displacement energies of the T=1, J=0 states of A=42 nuclei

    International Nuclear Information System (INIS)

    Sato, H.

    1978-01-01

    Coulomb displacement energies of the T=1, J=0 + and 6 1 + states of A=42 nuclei are analyzed with previously known charge dependent forces and effects, and with the available Hartree-Fock single-particle wave functions. From the study of the Coulomb displacement energies of the 6 1 + states it is found that the present knowledge on the charge dependence, including a phenomenological charge symmetry breaking force previously introduced so as to help explain the Nolen-Schiffer anomaly, gives a sufficient and consistent explanation for both single-particle and two-particle systems. From the study of the 0 + states, it is found that the Coulomb displacement energies of the second 0 2 + states can be explained with a compensation between the smaller Coulomb energies of the second lowest two-particle state and larger ones of the deformed 4p-2h state. (Auth.)

  3. Displaced Sense: Displacement, Religion and Sense-making

    OpenAIRE

    Naidu, Maheshvari

    2016-01-01

    Whether formally categorized as refugees or not, displaced migrants experience varying degrees of vulnerability in relation to where they find themselves displaced. The internally displaced furthermore squat invisibly and outside the boundaries of the legal framework and incentive structures accorded to those classified as 'refugee'. They are thus arguably, by and large, left to source sustaining solutions for themselves. This article works through the theoretical prism of sense-making theory...

  4. Sleep quality among internally displaced Georgian adolescents and population-based controls.

    Science.gov (United States)

    Sakhelashvili, Irine; Eliozishvili, Marine; Lortkipanidze, Nani; Oniani, Nikoloz; Cervena, Katerina; Darchia, Nato

    2016-09-01

    Sleep problems in children and adolescents are a significant public health concern and may be linked to a variety of psychoemotional difficulties. This study aimed to evaluate sleep quality and associated factors in conflict-affected Georgian adolescents after 9 months of forced displacement. Thirty-three internally displaced adolescents (mean age 11.4 years) and 33 adolescents (mean age 10.8 years) from the general population completed the Epworth Sleepiness Scale and the Children's Depression Inventory (CDI). Parents completed the Children's Sleep-Wake Scale and provided information on their socioeconomic status (SES) and the adolescents' sleep behavior, academic performance, and peer social relationships. The groups differed significantly in sleep quality, peer relationships, SES, and CDI scores. In the internally displaced group, the only significant predictor of sleep quality was SES, which increased the predictive capacity of the model (demographic and psychosocial variables) by 20% in the hierarchical analyses. The most significant predictor in the non-internally displaced group was CDI. This research indicates that displacement may affect sleep quality and psychosocial functioning. The importance of family SES as a contributing factor to displaced adolescents' poor sleep quality is highlighted. An integrated approach designed to improve the psychosocial environment of internally displaced adolescents is needed for their protection. © The Author(s) 2015.

  5. Fiber interferometer combining sub-nm displacement resolution with miniaturized sensor head

    NARCIS (Netherlands)

    Cheng, L.K.; Hagen, R.A.J.; Schriek, L.N.; Toet, P.M.; Togt, O.E. van der

    2017-01-01

    The presented interferometer concept enables high-accuracy target displacement measurement in difficult accessible locations and the development of small fiber optic sensor to measure other physical parameters e.g. pressure, vibration, gravity force, etc.. Furthermore, this configuration is

  6. A force transmission system based on a tulip-shaped electrostatic clutch for haptic display devices

    Science.gov (United States)

    Sasaki, Hikaru; Shikida, Mitsuhiro; Sato, Kazuo

    2006-12-01

    This paper describes a novel type of force transmission system for haptic display devices. The system consists of an array of end-effecter elements, a force/displacement transmitter and a single actuator producing a large force/displacement. It has tulip-shaped electrostatic clutch devices to distribute the force/displacement from the actuator among the individual end effecters. The specifications of three components were determined to stimulate touched human fingers. The components were fabricated by using micro-electromechanical systems and conventional machining technologies, and finally they were assembled by hand. The performance of the assembled transmission system was experimentally examined and it was confirmed that each projection in the arrayed end effecters could be moved individually. The actuator in a system whose total size was only 3.0 cm × 3.0 cm × 4.0 cm produced a 600 mN force and displaced individual array elements by 18 µm.

  7. Numerical studies on the force characteristic of superconducting linear synchronous motor with HTS bulk magnet

    Science.gov (United States)

    Tang, Junjie; Li, Jing; Li, Xiang; Han, Le

    2018-03-01

    High temperature superconductor (HTS) bulks have significant potential use in linear motor application act as quasi-permanent magnet to replace traditional magnets. Force characteristic between HTS bulk magnet and traveling magnetic field was investigated with numerical simulation and experimental measurement in this paper. Influences of bulk height and number on the force characteristic were studied by the finite element model considering the nonlinear E-J relationship. Study was also made on addition of a back iron plate to the bulk magnet. Besides, force characteristic of bulk was compared with the permanent magnet results. The small initial decrease of the thrust could be explained by inside superconducting current redistribution. It was found that efficiency of linear motor did not increase by adding more bulk magnets. The bulk magnet will be remagnetized instead of erasing trapped field with the increase of the traveling magnetic field strength. The conclusions are helpful in prediction and design the linear motor with HTS bulk magnet.

  8. Childhood Migrants: Territories, Journeys and Displacements, in Cronwell Jara’s Montacerdos

    Directory of Open Access Journals (Sweden)

    Natalia Andrea Alzate

    2017-11-01

    Full Text Available This article analyzes the writing of forced displacement in the novel Montacerdos (1981, by the Peruvian author Cronwell Jara. The narration gives an insight in the mobile universe of migrant children and suggests a cultural construction of childhood that, in contrast to the hegemonic vision, validates its existence in the displacement. The marks of migration that shape the childhood of the principal characters are narrated through the memory of a female voice. The body and the house appear as topoi of violence and marginality.

  9. The distinct element analysis for swelling pressure test of bentonite. Discussion on the effects of wall friction force and aspect ratio of specimen

    International Nuclear Information System (INIS)

    Shimizu, Hiroyuki; Kikuchi, Hirohito; Fujita, Tomoo; Tanai, Kenji

    2011-10-01

    For geological isolation systems for radioactive waste, bentonite based material is assumed to be used as a buffer material. The swelling characteristics of the bentonite based material are expected to fill up the void space around the radioactive wastes by swelling. In general, swelling characteristics and properties of bentonite are evaluated by the laboratory tests. However, due to the lack of standardization of testing method for bentonite, the accuracy and reproducibility of the testing results are not sufficiently proved. In this study, bentonite swelling pressure test were simulated by newly developed Distinct Element Method (DEM) code, and the effects of wall friction force and aspect ratio of bentonite specimen were discussed. As a result, the followings were found. In the beginning of the swelling pressure test, since swelling occurs only around the fluid injection side of the specimen, wall friction force acts only in the swelling area and the specimen moves to opposite side from fluid injection side. However, when the entire specimen started swelling, displacement of the specimen prevented by the wall friction force, and the specimen is pressed against the pressure measurement side. Then, the swelling pressure measured on the pressure measurement side increases. Such displacement in the specimen is significantly affected by the decreasing of mechanical properties and the difference of saturation in the bentonite specimen during the fluid infiltration. Moreover, when the aspect ratio of the specimen is large, the displacement of the particle in the specimen becomes large and the area on which the wall frictional force acts is also large. Therefore, measured swelling pressure increases more greatly as the aspect ratio of the specimen increases. To contributes to the standardization of laboratory test methods for bentonite, these effects of wall friction force revealed by the DEM simulation should be verified through laboratory experiments. (author)

  10. White Collar Displacement: Job Erosion in the Service Sector.

    Science.gov (United States)

    Golden, Lonnie; Danann, Sharon

    The National Commission for Employment Policy estimates that 19 million workers--17 percent of the work force--are in jobs directly threatened by office automation, and the consequences of the displacement of clerical workers due to increasing office computerization are as serious as those from manufacturing job loss. Between 1983 and 1988, almost…

  11. Unsteady force characteristics on foils undergoing pitching motion

    International Nuclear Information System (INIS)

    Yang, Chang Jo

    2006-01-01

    In the present study the unsteady forces acting on the pitching foils such as a flat plate, NACA0010, NACA0020, NACA65-0910 and BTE have been measured by using a six-axis sensor in a circulating water tunnel at a low Reynolds number region. The unsteady characteristics of the dynamic drag and lift have been compared to the quasi-steady ones which are measured under the stationary condition. The pitching motion is available for keeping the lift higher after the separation occurs. Especially, the characteristics of the dynamic lift are quite different from the quasi-steady one at high pitching frequency regions. As the pitching frequency deceases, the amplitude of the dynamic lift becomes closer to the quasi-steady one. However, the phase remains different between the steady and unsteady conditions even at low pitching frequencies. On the other hand, the dynamic drag is governed strongly by the angle of attack

  12. Initial studies on the variations of load-displacement curves of in vivo human healthy heel pads

    DEFF Research Database (Denmark)

    Matteoli, Sara; Wilhjelm, Jens E.; Virga, Antonio

    2011-01-01

    The aim of this study was to quantify on the measurement variation of in vivo load-displacement curves by using a group of human healthy heel pads. The recordings were done with a compression device measuring force and displacement. Twenty three heel pads, one from each of 23 subjects aged 20...

  13. Nonlinear structural analysis using integrated force method

    Indian Academy of Sciences (India)

    A new formulation termed the Integrated Force Method (IFM) was proposed by Patnaik ... nated ``Structure (nY m)'' where (nY m) are the force and displacement degrees of ..... Patnaik S N, Yadagiri S 1976 Frequency analysis of structures.

  14. An experimental and numerical investigation of crossflow effects in two-phase displacements

    DEFF Research Database (Denmark)

    Cinar, Y.; Jessen, Kristian; Berenblyum, Roman

    2006-01-01

    In this paper, we present flow visualization experiments and numerical simulations that demonstrate the combined effects of viscous and capillary forces and gravity segregation on crossflow that occurs in two-phase displacements in layered porous media. We report results of a series of immiscible...... flooding experiments in 2D, two-layered glass bead models. Favorable mobility-ratio imbibition and unfavorable mobility-ratio drainage experiments were performed. We used pre-equilibrated immiscible phases from a ternary isooctane/isopropanol/water system, which allowed control of the interfacial tension....... The experiments also illustrate the complex interplay of capillary, gravity, and viscous forces that controls crossflow. The experimental results confirm that the transition ranges of scaling groups suggested by Zhou et al. (1994) are appropriate/valid. We report also results of simulations of the displacement...

  15. Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

    Science.gov (United States)

    Hsu, Chao-Jung; Kim, Janis; Tang, Rongnian; Roth, Elliot J; Rymer, William Z; Wu, Ming

    2017-10-01

    To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  16. Restoring force characteristics of the steel frames of nuclear power station buildings, (1)

    International Nuclear Information System (INIS)

    Nakamura, N.; Tomura, H.; Takahashi, Y.; Saeki, T.; Tanaka, N.; Inada, Y.; Hirotani, T.

    1991-01-01

    In this paper, by using data obtained in experiments on reduced scale specimens of actual size of X type braces and by analyzing data previously obtained from K type brace experiments, we will propose simple and practical restoring force characteristics models of both types of the braces in the steel framed buildings. X and K type braces are the principal earthquake resistant elements in the steel frames of nuclear power station buildings. Therefore the results of past research and experiments were examined, and 11 reduced scale models simulating actual X type braced frames were subjected to static lateral loading tests. The simple and practical restoring force characteristics models were proposed for the design of the X and K braces. (J.P.N.)

  17. Displacement of the hip center of rotation after arthroplasty of Crowe III and IV dysplasia: a radiological and biomechanical study.

    Science.gov (United States)

    Abolghasemian, Mansour; Samiezadeh, Saeid; Jafari, Davood; Bougherara, Habiba; Gross, Allan E; Ghazavi, Mohammad T

    2013-06-01

    To study the direction and biomechanical consequences of hip center of rotation (HCOR) migration in Crowe type III and VI hips after total hip arthroplasty, post-operative radiographs and CT scans of several unilaterally affected hips were evaluated. Using a three-dimensional model of the human hip, the HCOR was moved in all directions, and joint reaction force (JRF) and abductor muscle force (AMF) were calculated for single-leg stance configuration. Comparing to the normal side, HCOR had displaced medially and inferiorly by an average of 23.4% and 20.8%, respectively, of the normal femoral head diameter. Significant decreases in JRF (13%) and AMF (46.13%) were observed in a presumptive case with that amount of displacement. Isolated inferior displacement had a small, increasing effect on these forces. In Crowe type III and IV hips, the HCOR migrates inferiorly and medially after THA, resulting in a decrease in JRF, AMF, and abductor muscle contraction force. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Two-Phase Gas-Liquid Flow Structure Characteristics under Periodic Cross Forces Action

    Directory of Open Access Journals (Sweden)

    V. V. Perevezentsev

    2015-01-01

    Full Text Available The article presents a study of two-phase gas-liquid flow under the action of periodic cross forces. The work objective is to obtain experimental data for further analysis and have structure characteristics of the two-phase flow movement. For research, to obtain data without disturbing effect on the flow were used optic PIV (Particle Image Visualization methods because of their noninvasiveness. The cross forces influence was provided by an experimental stand design to change the angular amplitudes and the periods of channel movement cycle with two-phase flow. In the range of volume gas rates was shown a water flow rate versus the inclination angle of immovable riser section and the characteristic angular amplitudes and periods of riser section inclination cycle under periodic cross forces. Data on distribution of average water velocity in twophase flow in abovementioned cases were also obtained. These data allowed us to draw a conclusion that a velocity distribution depends on the angular amplitude and on the period of the riser section roll cycle. This article belongs to publications, which study two-phase flows with no disturbing effect on them. Obtained data give an insight into understanding a pattern of twophase gas-liquid flow under the action of periodic cross forces and can be used to verify the mathematical models of the CFD thermo-hydraulic codes. In the future, the work development expects taking measurements with more frequent interval in the ranges of angular amplitudes and periods of the channel movement cycle and create a mathematical model to show the action of periodic cross forces on two-phase gas-liquid flow.

  19. Simultaneous measurement of dynamic force and spatial thin film thickness between deformable and solid surfaces by integrated thin liquid film force apparatus.

    Science.gov (United States)

    Zhang, Xurui; Tchoukov, Plamen; Manica, Rogerio; Wang, Louxiang; Liu, Qingxia; Xu, Zhenghe

    2016-11-09

    Interactions involving deformable surfaces reveal a number of distinguishing physicochemical characteristics that do not exist in interactions between rigid solid surfaces. A unique fully custom-designed instrument, referred to as integrated thin liquid film force apparatus (ITLFFA), was developed to study the interactions between one deformable and one solid surface in liquid. Incorporating a bimorph force sensor with interferometry, this device allows for the simultaneous measurement of the time-dependent interaction force and the corresponding spatiotemporal film thickness of the intervening liquid film. The ITLFFA possesses the specific feature of conducting measurement under a wide range of hydrodynamic conditions, with a displacement velocity of deformable surfaces ranging from 2 μm s -1 to 50 mm s -1 . Equipped with a high speed camera, the results of a bubble interacting with hydrophilic and partially hydrophobic surfaces in aqueous solutions indicated that ITLFFA can provide information on interaction forces and thin liquid film drainage dynamics not only in a stable film but also in films of the quick rupture process. The weak interaction force was extracted from a measured film profile. Because of its well-characterized experimental conditions, ITLFFA permits the accurate and quantitative comparison/validation between measured and calculated interaction forces and temporal film profiles.

  20. Evaluation of the Perceptual Characteristics of a Force Induced by Asymmetric Vibrations.

    Science.gov (United States)

    Tanabe, Takeshi; Yano, Hiroaki; Iwata, Hiroo

    2017-08-29

    This paper describes the properties of proprioceptive sensations induced by asymmetric vibration using a vibration speaker-type non-grounded haptic interface. We confirm that the vibration speaker generates a perceived force that pulls or pushes a user's hand in a particular direction when an asymmetric amplitude signal that is generated by inverting a part of a sine wave is input. In this paper, to verify the system with respect to various factors of force perception caused by asymmetric vibration, we conducted six experiments and the following results were obtained. (1) The force vector can be controlled by reversing the asymmetric waves. (2) By investigating the physical characteristics of the vibration, asymmetric vibration was confirmed. (3) The presentation of vibration in the shear direction on the finger pad is effective. (4) The point of subjective equality of the perceived force can be controlled by up to 0.43 N by changing the amplitude voltage of the input signals. (5) The minimum stimulation time required for force perception is 66.7 ms. (6) When the vibration is continuously presented for 40 to 50 s, the perceived force decreases because of adaptation. Hence, we confirmed that we can control both the direction and magnitude of the reaction force by changing the input signal of the vibration speaker.

  1. Ground reaction force characteristics of Tai Chi push hand.

    Science.gov (United States)

    Chang, Yao-Ting; Chang, Jia-Hao; Huang, Chen-Fu

    2014-01-01

    Push Hand is an advanced training technique for the Yang-style old frame 108 forms Tai Chi Chuan. It is performed by two practitioners. To clarify how people use forces during Push Hand training, it is important to review the ground reaction force (GRF). Here, we quantify the characteristics of the GRF during Push Hand training. Kinematic data and GRF data from 10 Tai Chi Chuan practitioners (29.9 ± 7.87 years) were synchronously recorded using a three-dimensional motion analysis system (200 frames · s(-1)) and three-dimensional force plates (1000 Hz). The resultant GRF for both feet for the 0%, 50% and 100% phases of attack and defence were compared to body weight using a paired-samples t-test. The differences in the resultant GRF between the 0%, 50% and 100% phases of attack and defence were tested by one-way repeated-measures ANOVA. The significance level was set to 0.05. The total resultant GRF was almost equal to the participant's body weight in push hand. This result was consistent throughout the entire push hand process. Our results revealed that the GRF was comparable to the body weight, implying that practitioners do not push or resist their opponents during the push hand process.

  2. Down force calibration stand test report

    International Nuclear Information System (INIS)

    BOGER, R.M.

    1999-01-01

    The Down Force Calibration Stand was developed to provide an improved means of calibrating equipment used to apply, display and record Core Sample Truck (CST) down force. Originally, four springs were used in parallel to provide a system of resistance that allowed increasing force over increasing displacement. This spring system, though originally deemed adequate, was eventually found to be unstable laterally. For this reason, it was determined that a new method for resisting down force was needed

  3. Analysis of force characteristics of a superconducting ball in a given magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jianhua, E-mail: liujianhua@mail.iee.ac.c [Institute of Electrical Engineering, Chinese Academy of Sciences, No. 6 Beiertiao, Zhongguancun, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Wang Qiuliang; Yan Luguang [Institute of Electrical Engineering, Chinese Academy of Sciences, No. 6 Beiertiao, Zhongguancun, Beijing 100190 (China)

    2009-07-01

    The electromagnetic force characteristics along Z direction of a superconducting ball levitated by spherical coils with shaping blocks are calculated based on a semi-analytical method. The calculating results from the semi-analytical method are compared with the finite element analysis (FEA) method through a calculation example. The method can be applied to further analysis of dynamic characteristics and parameter optimization in the suspension system.

  4. The Psychological Impact of Forced Displacement and Related Risk Factors on Eastern Congolese Adolescents Affected by War

    Science.gov (United States)

    Mels, Cindy; Derluyn, Ilse; Broekaert, Eric; Rosseel, Yves

    2010-01-01

    Background: While the current knowledge base on the mental health effects of displacement is mainly limited to refugees residing in industrialised countries, this paper examines the impact of war-induced displacement and related risk factors on the mental health of Eastern Congolese adolescents, and compares currently internally displaced…

  5. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    International Nuclear Information System (INIS)

    Kim, Hyo-gon; Han, Changsoo; Lee, Jong-won; Park, Sangdeok

    2015-01-01

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program

  6. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-gon; Han, Changsoo [Hanyang University, Seoul (Korea, Republic of); Lee, Jong-won [Korea University of Science and Technology, Seoul (Korea, Republic of); Park, Sangdeok [Korea Institute of Industrial Technology, Seoul (Korea, Republic of)

    2015-02-15

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

  7. Three-dimensional displacement measurement by fringe projection and speckle photography

    International Nuclear Information System (INIS)

    Barrientos, B.; Garcia-Marquez, J.; Cerca, M.; Hernandez-Bernal, C.

    2008-01-01

    3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suited for this type of studies

  8. Vibration Characteristics of a Mistuned Bladed Disk considering the Effect of Coriolis Forces

    Directory of Open Access Journals (Sweden)

    Xuanen Kan

    2016-01-01

    Full Text Available To investigate the influence of Coriolis force on vibration characteristics of mistuned bladed disk, a bladed disk with 22 blades is employed and the effects of different rotational speeds and excitation engine orders on the maximum forced response are discussed considering the effects of Coriolis forces. The results show that if there are frequency veering regions, the largest split of double natural frequencies of each modal family considering the effects of Coriolis forces appears at frequency veering region. In addition, the amplitude magnification factor considering the Coriolis effects is increased by 1.02% compared to the system without considering the Coriolis effects as the rotating speed is 3000 rpm, while the amplitude magnification factor is increased by 2.76% as the rotating speed is 10000 rpm. The results indicate that the amplitude magnification factor may be moderately enhanced with the increasing of rotating speed. Moreover, the position of the maximum forced response of bladed disk may shift from one blade to another with the increasing of the rotational speed, when the effects of Coriolis forces are considered.

  9. On the Coulomb displacement energy

    International Nuclear Information System (INIS)

    Sato, H.

    1976-01-01

    The Coulomb displacement energies of the T=1/2 mirror nuclei (A=15,17,27,29,31,33,39 and 41) are re-examined with the best available HF wave functions (the DME and the Skyrme II interaction), with the inclusion of all electromagnetic corrections. The results are compared with the experimental s.p. charge dependent energies extracted from the experimental data taking into account admixtures of core-excitation corrections with the help of present shell-model and co-existence model calculations. Although the so-called Nolen-Schiffer anomaly is not removed by these improvements, it is found that the remaining observed anomalies in the ground states of s.p. and s.h. systems can be resolved with the introduction of a simple, phenomenological charge symmetry breaking nucleon-nucleon force. This force can also account for the observed anomalies in the higher excited s.p. states, while those of the deeper s.h. states need further explanation. (Auth.)

  10. 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.

  11. Effects of Buoyancy Forces on Immiscible Water/Oil Displacements in a Vertically Oriented Porous Medium Effets des facteurs de flottabilité sur les déplacements non-miscibles eau/huile dans un milieu poreux vertical

    Directory of Open Access Journals (Sweden)

    Thirunavu S. R.

    2006-11-01

    Full Text Available The effects of buoyancy forces on liquid-liquid displacement processes occurring in porous media are important in a variety of practical situations, in particular during the displacement of oil from partially-depleted underground reservoirs by means of aqueous solutions. Most previous studies involving the visualization of water/oil displacements in porous media have been undertaken in horizontal two-dimensional porous medium cells. The objective of the present work was to determine the effects of buoyancy forces; on the fingering pattern and oil recovery by conducting immiscible displacement experiments in two-dimensional consolidated porous medium cells aligned in the vertical plane. In order to obtain a clear understanding of the favourable and unfavourable effects of buoyancy forces, experiments were carried out in three different flow modes, namely horizontal, vertical upward, and vertical downward. As the effects of buoyancy forces are negligible for two-dimensional porous media in the horizontal flow mode, the recoveries obtained in this mode were used as a reference for comparison with those obtained in the two vertical modes. Displacements using five different density ratios were studied. The breakthrough time and percentage oil recovery were measured in each case. The effects of buoyancy forces, viscous forces, and capillary forces, as well as the injection flow rate, were also recorded. The results obtained indicate that the effects of buoyancy forces are very pronounced at low flow rates and low oil/water density ratios, and that even a slight increase in the flow rate causes the buoyancy forces to rapidly become less significant. Les facteurs de flottabilité exercent un effet important sur les déplacements liquide/liquide en milieu poreux dans toute une gamme de situations pratiques, en particulier lorsqu'on veut déplacer l'huile de roches réservoirs partiellement épuisées à l'aide de solutions aqueuses. La plupart des

  12. Computational fluid dynamics modelling of displacement natural ventilation.

    OpenAIRE

    Ji, Yingchun

    2005-01-01

    Natural ventilation is widely recognised as contributing towards low-energy building design. The requirement to reduce energy usage in new buildings has rejuvenated interest in natural ventilation. This thesis deals with computer modelling of natural displacement ventilation driven either by buoyancy or buoyancy combined with wind forces. Two benchmarks have been developed using computational fluid dynamics (CFD) in order to evaluate the accuracy with which CFD is able to mo...

  13. Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time.

    Science.gov (United States)

    Barker, Leland A; Harry, John R; Mercer, John A

    2018-01-01

    Barker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI). Twenty-six, Division-I, male, soccer players performed 3 maximum effort countermovement jumps (CMJs) on a dual-force platform system that measured 3-dimensional kinetic data. The trial producing peak jump height was used for analysis. Vertical GRF (Fz) variables were divided into unloading, eccentric, amortization, and concentric phases and correlated with jump height, RSI (RSI = jump height/jump time), and jump time (from start to takeoff). Significant correlations were observed between jump height and RSI, concentric kinetic energy, peak power, concentric work, and concentric displacement. Significant correlations were observed between RSI and jump time, peak power, unload Fz, eccentric work, eccentric rate of force development (RFD), amortization Fz, amortization time, second Fz peak, average concentric Fz, and concentric displacement. Significant correlations were observed between jump time and unload Fz, eccentric work, eccentric RFD, amortization Fz, amortization time, average concentric Fz, and concentric work. In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance.

  14. Sideways wall force produced during tokamak disruptions

    Science.gov (United States)

    Strauss, H.; Paccagnella, R.; Breslau, J.; Sugiyama, L.; Jardin, S.

    2013-07-01

    A critical issue for ITER is to evaluate the forces produced on the surrounding conducting structures during plasma disruptions. We calculate the non-axisymmetric ‘sideways’ wall force Fx, produced in disruptions. Simulations were carried out of disruptions produced by destabilization of n = 1 modes by a vertical displacement event (VDE). The force depends strongly on γτwall, where γ is the mode growth rate and τwall is the wall penetration time, and is largest for γτwall = constant, which depends on initial conditions. Simulations of disruptions caused by a model of massive gas injection were also performed. It was found that the wall force increases approximately offset linearly with the displacement from the magnetic axis produced by a VDE. These results are also obtained with an analytical model. Disruptions are accompanied by toroidal variation of the plasma current Iφ. This is caused by toroidal variation of the halo current, as verified computationally and analytically.

  15. Uranium mining and milling work force characteristics in the western US

    International Nuclear Information System (INIS)

    Rapp, D.A.

    1980-12-01

    This report presents the results of a survey of the socioeconomic characteristics associated with 11 uranium mine and mill operations in 5 Western States. Comparisons are made with the socioeconomic characteristics of construction and operating crews for coal mines and utility plants in eight Western States. Worker productivity also is compared with that in similar types of coal and uranium mining operations. We found that there existed no significant differences between the socioeconomic characteristics of construction and operating crews and the secondary employment impacts associated with uranium mines and mills when compared with those associated with coal mines and utility plants requiring similar skills at comparable locations. In addition, our survey includes a comparison of several characteristics associated with the households of basic and nonbasic work forces and concludes that significant changes have occurred in the last 5 yr. Accordingly, we recommend additional monitoring and updating of data used in several economic forecasting models to avoid unwarranted delays in achieving national energy goals

  16. The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

    Directory of Open Access Journals (Sweden)

    Mingying Huo

    2017-01-01

    Full Text Available Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

  17. Force control of a magnetorheological damper using an elementary hysteresis model-based feedforward neural network

    International Nuclear Information System (INIS)

    Ekkachai, Kittipong; Nilkhamhang, Itthisek; Tungpimolrut, Kanokvate

    2013-01-01

    An inverse controller is proposed for a magnetorheological (MR) damper that consists of a hysteresis model and a voltage controller. The force characteristics of the MR damper caused by excitation signals are represented by a feedforward neural network (FNN) with an elementary hysteresis model (EHM). The voltage controller is constructed using another FNN to calculate a suitable input signal that will allow the MR damper to produce the desired damping force. The performance of the proposed EHM-based FNN controller is experimentally compared to existing control methodologies, such as clipped-optimal control, signum function control, conventional FNN, and recurrent neural network with displacement or velocity inputs. The results show that the proposed controller, which does not require force feedback to implement, provides excellent accuracy, fast response time, and lower energy consumption. (paper)

  18. Theory and computation of general force balance in non-axisymmetric tokamak equilibria

    Science.gov (United States)

    Park, Jong-Kyu; Logan, Nikolas; Wang, Zhirui; Kim, Kimin; Boozer, Allen; Liu, Yueqiang; Menard, Jonathan

    2014-10-01

    Non-axisymmetric equilibria in tokamaks can be effectively described by linearized force balance. In addition to the conventional isotropic pressure force, there are three important components that can strongly contribute to the force balance; rotational, anisotropic tensor pressure, and externally given forces, i.e. ∇ --> p + ρv-> . ∇ --> v-> + ∇ --> . Π + f-> = j-> × B-> , especially in, but not limited to, high β and rotating plasmas. Within the assumption of nested flux surfaces, Maxwell equations and energy minimization lead to the modified-generalized Newcomb equation for radial displacements with simple algebraic relations for perpendicular and parallel displacements, including an inhomogeneous term if any of the forces are not explicitly dependent on displacements. The general perturbed equilibrium code (GPEC) solves this force balance consistent with energy and torque given by external perturbations. Local and global behaviors of solutions will be discussed when ∇ --> . Π is solved by the semi-analytic code PENT and will be compared with MARS-K. Any first-principle transport code calculating ∇ --> . Π or f-> , e.g. POCA, can also be incorporated without demanding iterations. This work was supported by DOE Contract DE-AC02-09CH11466.

  19. The effect of adhesion on the contact radius in atomic force microscopy indentation

    International Nuclear Information System (INIS)

    Sirghi, L; Rossi, F

    2009-01-01

    The effect of adhesion on nanoscale indentation experiments makes the interpretation of force-displacement curves acquired in these experiments very difficult. The indentation force results from the addition of adhesive and elastic forces at the indenter-sample contact. The evolution of the two forces during the indentation is determined by the variation of the indenter-sample contact radius. In the present work the variation of contact radius during atomic force microscopy (AFM) indentation of elastic and adhesive samples with conical indenters (AFM tips) is indirectly determined by measurements of the contact dynamic stiffness. For weak sample deformations, the contact radius is determined mainly by the adhesion force and indenter apex radius. For strong sample deformations, the contact radius increases linearly with the increase of the indenter displacement, the slope of this linear dependence being in agreement with Sneddon's theory of indentation (Sneddon 1965 Int. J. Eng. Sci. 3 47). Based on these results, a theoretical expression of indentation force dependence on displacement is found. This expression allows for determination of the thermodynamic work of adhesion at the indenter-sample interface and the sample elasticity modulus.

  20. 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....

  1. Electrostatic characteristics of nanostructures investigated using electric force microscopy

    International Nuclear Information System (INIS)

    Qiu, X.H.; Qi, G.C.; Yang, Y.L.; Wang, C.

    2008-01-01

    Nanosized materials possess many interesting physical and chemical properties that differ significantly from their macroscopic counterparts. Understanding the size- and shape-dependent properties of nanostructures are of great value to rational design of nanomaterials with desired functionality. Electric force microscopy (EFM) and its variations offer unique opportunities to deepen our insights into the electrical characteristics of nanostructures. In this paper, we review recent progress of this versatile technique and its applications in studying the electrical properties of nanosized materials. A variety of important issues in EFM experimentation and theoretical modeling are discussed, with an emphasis on the ongoing efforts to improve the precision in quantitative measurements of charge density and dielectric properties of nanostructures. - Graphical abstract: We review recent progress of electric force microscopy (EFM) and its applications in studying the electrical properties of nanostructures. A variety of important issues in EFM experimentation and theoretical modeling are discussed, with an emphasis on the ongoing efforts to improve the precision in quantitative measurements of charge density and dielectric properties of nanostructures

  2. Muscle specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

    DEFF Research Database (Denmark)

    Olesen, Annesofie Thorup; Jensen, Bente Rona; Uhlendorf, Toni L

    2014-01-01

    length, passive stiffness and passive force of spastic GA were decreased whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However......, the extent of this interaction was not different in the spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes seen for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate......The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO) and plantaris (PL) were assessed in anesthetized spastic...

  3. 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.

  4. Comparison Between Elite and Subelite Swimmers on Dry Land and Tumble Turn Leg Extensor Force-Time Characteristics.

    Science.gov (United States)

    Jones, Julian V; Pyne, David B; Haff, G Greg; Newton, Robert U

    2018-06-01

    Jones, JV, Pyne, DB, Haff, GG, and Newton, RU. Comparison between elite and subelite swimmers on dry land and tumble turn leg extensor force-time characteristics. J Strength Cond Res 32(6): 1762-1769, 2018-Elite swimmers demonstrate faster swimming turn times that are potentially a result of having better strength-power characteristics than subelite swimmers. We quantified differences between dry-land and swimming turn force-time characteristics in elite swimmers and subelite swimmers. Subelite (11 males: 17.4 ± 0.6 years; 10 females: 17.1 ± 0.6 years) and elite swimmers (15 male: 23.2 ± 2.3 years; 7 female: 21.6 ± 2.5 years) were tested in a cross-sectional design. All swimmers performed a body weight and loaded (20 kg females, 30 kg males) squat jump (SJ) on a portable force platform. On the same day, all swimmers completed swimming turn analyses using a force platform fixed within the pool wall. The magnitude of difference between groups was estimated using a standardized mean difference (effect size statistic). Elite male and female swimmers had superior swimming turn and dry-land force-time characteristics to subelite swimmers in all tests. The standardized mean differences between groups ranged from small to very large. The largest differences were SJ peak velocity unloaded (3.07 ± 1.0 m·s males, 3.49 ± 2.29 m·s females; standardized mean difference ± 90% confidence limits) and SJ peak power unloaded (2.59 ± 0.79 w male, 2.80 ± 1.64 w female) with elite male and female swimmers having a ∼25-50% higher performance than the subelites in both characteristics. Elite swimmers exhibit superior strength and power characteristics for the swimming turn compared with younger and less experienced swimmers. A well-planned and executed strength and conditioning program is needed for emerging swimmers to develop these qualities, as they transition to senior levels.

  5. Analysis of dynamic cantilever behavior in tapping mode atomic force microscopy.

    Science.gov (United States)

    Deng, Wenqi; Zhang, Guang-Ming; Murphy, Mark F; Lilley, Francis; Harvey, David M; Burton, David R

    2015-10-01

    Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplitude images. Although the behavior of tapping mode AFM has been investigated using mathematical modeling, comprehensive understanding of the behavior of tapping mode AFM still poses a significant challenge to the AFM community, involving issues such as the correct interpretation of the phase images. In this paper, the cantilever's dynamic behavior in tapping mode AFM is studied through a three dimensional finite element method. The cantilever's dynamic displacement responses are firstly obtained via simulation under different tip-sample separations, and for different tip-sample interaction forces, such as elastic force, adhesion force, viscosity force, and the van der Waals force, which correspond to the cantilever's action upon various different representative computer-generated test samples. Simulated results show that the dynamic cantilever displacement response can be divided into three zones: a free vibration zone, a transition zone, and a contact vibration zone. Phase trajectory, phase shift, transition time, pseudo stable amplitude, and frequency changes are then analyzed from the dynamic displacement responses that are obtained. Finally, experiments are carried out on a real AFM system to support the findings of the simulations. © 2015 Wiley Periodicals, Inc.

  6. Is automation labor-displacing? : Productivity growth, employment, and the labor share

    NARCIS (Netherlands)

    Autor, David; Salomons, A.M.|info:eu-repo/dai/nl/338041575

    2018-01-01

    Is automation a labor-displacing force? This possibility is both an age-old concern and at the heart of a new theoretical literature considering how labor immiseration may result from a wave of “brilliant machines,” which is in part motivated by declining labor shares in many developed countries.

  7. The Paradox of Local Participation in Forced Displacement and Resettlement Caused by the Development Process

    Directory of Open Access Journals (Sweden)

    INGA-LILL ARONSSON

    2009-02-01

    Full Text Available This article is an investigation of the theoretical and empirical concept of local participation, as it is used in the field of development-induced forced displacement and relocation (in short, DFDR. Local participation has repeatedly proved to be relevant with respect to the decrease of the negative impacts caused by DFDR on the people involved. Paradoxically, people who contribute to this process with their very culture and means of existence - including their land - often end up in chronic poverty, despite their participation in local decision-making. It appears that this concept, which was developed precisely in order to protect persons affected by poverty and supporting them in their attempt to overcome this poverty, contributes nevertheless to the destruction of their local culture, which shows signs of "inside cracking".Hence the necessity to answer two questions: is the concept of local participation deceitful or is it used erroneously? Do we need to reinterpret and rethink the way the project is conceived, planned and executed, taking into account its crucial elements with respect to risks and compensations? This approach seems to me to constitute a way to overcome blockages and avoid considering negotiations as an inflexible, univocal, hierarchical relation between two parties blocked into anasymmetrical power game without any possibility to escape from it. I have used the example of the hydroelectric dam project in Zimapán, Mexico, as a starting point for an ethnographic discussion of local participation2.

  8. Modeling of IPMC cantilever’s displacements and blocking forces

    Czech Academy of Sciences Publication Activity Database

    Vokoun, David; He, Q.; Heller, Luděk; Yu, M.; Dai, Z.

    2015-01-01

    Roč. 12, č. 1 (2015), s. 142-151 ISSN 1672-6529 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:68378271 Keywords : ionic polymer metal composite * actuator * blocking force * finite element method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.466, year: 2015

  9. Surface texture generation during cylindrical milling in the aspect of cutting force variations

    International Nuclear Information System (INIS)

    Wojciechowski, S; Twardowski, P; Pelic, M

    2014-01-01

    The work presented here concentrates on surface texture analysis, after cylindrical milling of hardened steel. Cutting force variations occurring in the machining process have direct influence on the cutter displacements and thus on the generated surface texture. Therefore, in these experiments, the influence of active number of teeth (z c ) on the cutting force variations was investigated. Cutting forces and cutter displacements were measured during machining process (online) using, namely piezoelectric force dynamometer and 3D laser vibrometer. Surface roughness parameters were measured using stylus surface profiler. The surface roughness model including cutting parameters (f z , D) and cutting force variations was also developed. The research revealed that in cylindrical milling process, cutting force variations have immediate influence on surface texture generation

  10. Development of Displacement Gages Exposed to Solid Rocket Motor Internal Environments

    Science.gov (United States)

    Bolton, D. E.; Cook, D. J.

    2003-01-01

    The Space Shuttle Reusable Solid Rocket Motor (RSRM) has three non-vented segment-to-segment case field joints. These joints use an interference fit J-joint that is bonded at assembly with a Pressure Sensitive Adhesive (PSA) inboard of redundant O-ring seals. Full-scale motor and sub-scale test article experience has shown that the ability to preclude gas leakage past the J-joint is a function of PSA type, joint moisture from pre-assembly humidity exposure, and the magnitude of joint displacement during motor operation. To more accurately determine the axial displacements at the J-joints, two thermally durable displacement gages (one mechanical and one electrical) were designed and developed. The mechanical displacement gage concept was generated first as a non-electrical, self-contained gage to capture the maximum magnitude of the J-joint motion. When it became feasible, the electrical displacement gage concept was generated second as a real-time linear displacement gage. Both of these gages were refined in development testing that included hot internal solid rocket motor environments and simulated vibration environments. As a result of this gage development effort, joint motions have been measured in static fired RSRM J-joints where intentional venting was produced (Flight Support Motor #8, FSM-8) and nominal non-vented behavior occurred (FSM-9 and FSM-10). This data gives new insight into the nominal characteristics of the three case J-joint positions (forward, center and aft) and characteristics of some case J-joints that became vented during motor operation. The data supports previous structural model predictions. These gages will also be useful in evaluating J-joint motion differences in a five-segment Space Shuttle solid rocket motor.

  11. A novel magnetorheological actuator for micro-motion control: identification of actuating characteristics

    International Nuclear Information System (INIS)

    Kaluvan, Suresh; Kim, Soomin; Choi, Seung-Bok; Thirumavalavan, Vinopraba

    2015-01-01

    A novel actuator using magnetorheological (MR) fluid sandwiched between two electrode type coils is proposed in this research work. The key enabling concept of the proposed actuator is to enhance the force due to the magnetic field produced by the electrode coil using the magnetorheological fluid. The direction and amount of current input to the top and bottom electrode coils decide the characteristics such as contraction, extension and the force generated by the actuator, respectively. To obtain the required displacement and actuation force, the viscosity of the MR fluid sandwiched between the two electrode coils is precisely varied by the input current. In this work, the MR fluid is operated in one of the most powerful modes, called squeeze mode, and hence the designed magnetorheological actuator is more powerful and precise. The experimental results shown in this paper show that it has a great advantage in micron-level displacement and vibration control applications. The main contribution of this innovative magnetorheological actuator design is that it can also behave like a damper. This technology will lead to a new dimension in the design of self-actuation and damping devices. In addition, the proposed magnetorheological actuator has additional advantages such as cost effectiveness and easy implementation. (paper)

  12. Psychological After-effects of War in Displaced Women

    Directory of Open Access Journals (Sweden)

    José Alonso Andrade Salazar

    2016-07-01

    Full Text Available The psychological after-effects of violence due to the armed conflict have left traumatic memories or indelible stigma in victimized women. Females are overrepresented since they compose more than half of the victims in the Colombian warfare. (Sierra, Calle, and Vélez, 2015. Thus, we considered the following research question: What psychological after-effects of war prevail in displaced women? In this research project, we defined psychological after-effects of war as signs, symptoms and psychological disorders based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. Moreover, we defined forced migration as the movement of people, families and groups away from their homes to other places. This movement is coerced by a powerful actor or group to expel, harass and uproot a person, group or community.   We adopted a social psychological perspective to study the after-effects of war in displaced women. This is a narrative review in which we included manuscripts from academic journals, institutional reports and books. The inclusion criteria were the following: manuscripts published and indexed from 2005 to 2015, and generalizability of the results.  We selected the following academic data-bases: Academic Search Complete, Medline, Redalyc, EBSCO, Google Scholar, and Science Direct. We selected 7 out of 50 papers that fulfilled the inclusion criteria. The results showed that displaced women suffer from mood, impulse control and behavioral disorders. These disorders prevail due to the after-effects of war. Whereas fear, helplessness, anger and uprooting are equally conducive to the emotional stability that they experience. We conclude that war directly and indirectly affects the mental health of women forced to emigrate, causing mental disorders and psychological alterations.

  13. 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...... a substantial share of their workers, for workers with at least three years of tenure. Displaced workers are more likely to commit offenses leading to conviction (probation, prison terms) for property crimes and for alcohol-related traffic violations in the two years following displacement. We find no evidence...... that displaced workers' propensity to commit crime is higher than non-displaced workers before the displacement event; but it is significantly higher afterwards. Displacement impacts crime over and above what is explained by earnings losses and weeks of unemployment following displacement....

  14. Study on Flow-Shifted Region Depending on Spool Displacement in Hydraulic Servo Valve with Hybrid Lap

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hwanghun; Yun, Sonam; Lee, Sungsoo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Yang, Jooho [Pukyong Nat' l Univ., Busan (Korea, Republic of)

    2013-03-15

    This study examined the static characteristics of a spool valve with a hybrid lap between the spool land and the sleeve. The static equation for the pressure characteristics was derived from flow equations that depend on the spool displacement, and the final model was derived from q{sub a}=q{sub b}=0 because the pressure characteristics test needs to block the control port in the valve. The static equation for the flow characteristics was derived from the pressure characteristics when the control port is open (q{sub a}=q{sub b}, p{sub a}=p{sub b}). The characteristic equation in the shifted region was assumed from the proportional relationship between the pressure-flow characteristics and the spool displacement.

  15. Energy dissipation unveils atomic displacement in the noncontact atomic force microscopy imaging of Si(111 )-(7 ×7 )

    Science.gov (United States)

    Arai, Toyoko; Inamura, Ryo; Kura, Daiki; Tomitori, Masahiko

    2018-03-01

    The kinetic energy of the oscillating cantilever of noncontact atomic force microscopy (nc-AFM) at room temperature was considerably dissipated over regions between a Si adatom and its neighboring rest atom for Si(111 )-(7 ×7 ) in close proximity to a Si tip on the cantilever. However, nc-AFM topographic images showed no atomic features over those regions, which were the hollow sites of the (7 ×7 ). This energy dissipation likely originated from displacement of Si adatoms with respect to the tip over the hollow sites, leading to a lateral shift of the adatoms toward the rest atom. This interaction led to hysteresis over each cantilever oscillation cycle; when the tip was retracted, the Si adatom likely returned to its original position. To confirm the atomic processes involved in the force interactions through Si dangling bonds, the Si(111 )-(7 ×7 ) surface was partly terminated with atomic hydrogen (H) and examined by nc-AFM. When the Si adatoms and/or the rest atoms were terminated with H, the hollow sites were not bright (less dissipation) in images of the energy dissipation channels by nc-AFM. The hollow sites acted as metastable sites for Si adatoms in surface diffusion and atom manipulation; thus, the dissipation energy which is saturated on the tip likely corresponds to the difference in the potential energy between the hollow site and the Si adatom site. In this study, we demonstrated the ability of dissipation channels of nc-AFM to enable visualization of the dynamics of atoms and molecules on surfaces, which cannot be revealed by nc-AFM topographic images alone.

  16. Gamma-point lattice free energy estimates from O(1) force calculations

    DEFF Research Database (Denmark)

    Voss, Johannes; Vegge, Tejs

    2008-01-01

    We present a new method for estimating the vibrational free energy of crystal (and molecular) structures employing only a single force calculation, for a particularly displaced configuration, in addition to the calculation of the ground state configuration. This displacement vector is the sum...

  17. A quasi-static algorithm that includes effects of characteristic time scales for simulating failures in brittle materials

    KAUST Repository

    Liu, Jinxing

    2013-04-24

    When the brittle heterogeneous material is simulated via lattice models, the quasi-static failure depends on the relative magnitudes of Telem, the characteristic releasing time of the internal forces of the broken elements and Tlattice, the characteristic relaxation time of the lattice, both of which are infinitesimal compared with Tload, the characteristic loading period. The load-unload (L-U) method is used for one extreme, Telem << Tlattice, whereas the force-release (F-R) method is used for the other, Telem T lattice. For cases between the above two extremes, we develop a new algorithm by combining the L-U and the F-R trial displacement fields to construct the new trial field. As a result, our algorithm includes both L-U and F-R failure characteristics, which allows us to observe the influence of the ratio of Telem to Tlattice by adjusting their contributions in the trial displacement field. Therefore, the material dependence of the snap-back instabilities is implemented by introducing one snap-back parameter γ. Although in principle catastrophic failures can hardly be predicted accurately without knowing all microstructural information, effects of γ can be captured by numerical simulations conducted on samples with exactly the same microstructure but different γs. Such a same-specimen-based study shows how the lattice behaves along with the changing ratio of the L-U and F-R components. © 2013 The Author(s).

  18. 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

  19. Dynamic characteristics and mechatronics model for maglev blood pump

    Science.gov (United States)

    Sun, Kun; Chen, Chen

    2017-01-01

    Magnetic bearing system(MBs) has been developed in the new-generation blood pump due to its low power consumption, low blood trauma and high durability. However, MBs for a blood pump were almost influenced by a series of factors such as hemodynamics, rotation speeds and actuator response in working fluids, compared with those applied in other industrial fields. In this study, the dynamic characteristics of MBs in fluid environments, including the influence of the pumping fluid and rotation of the impeller on the radial dynamic model were investigated by measuring the frequency response to sinusoidal excitation upon coils, and the response of radial displacement during a raise in the speed. The excitation tests were conducted under conditions in which the blood pump was levitated in air and water and with or without rotation. The experimental and simulated results indicate that rotations of the impeller affected the characteristics of MBs in water apparently, and the vibration in water was decreased, compared with that in air due to the hydraulic force. During the start-up and rotation, the actuator failed to operate fully and timely, and the voltage supplied can be chosen under the consideration of the rotor displacement and consumption.

  20. 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...

  1. Traumatic corneal flap displacement after laser in situ keratomileusis (LASIK).

    Science.gov (United States)

    Tsai, Tsung-Han; Peng, Kai-Ling; Lin, Chien-Jen

    2017-01-01

    Laser in situ keratomileusis (LASIK) is the most common and popular procedure performed for the correction of refractive errors in the last two decades. We report a case of traumatic flap displacement with flap folding which occurred 3 years after LASIK was performed. Previous literature suggests that vision prognosis would be closely related to proper and prompt management of traumatic flap displacement with flap folding 3 years after LASIK. A 23-year-old female presented to our hospital who had undergone uneventful LASIK in both eyes 3 years prior. Unfortunately, she had suffered a blunt trauma in her right eye in a car accident. A late onset of corneal flap displacement was found with upper and lower portion of the flap being folded inside the corneal bed. Surgical intervention for debridement with subsequent reposition of corneal flap was performed as soon as possible in the operating room. A bandage contact lens was placed, and topical antibiotic and corticosteroids were given postoperatively. Two days after the operation, the displaced corneal flap was found to be well attached smoothly on the corneal bed without folds. The best-corrected visual acuity was 6/6 with refraction of -0.75 D to 1.0 D ×175° in her right eye 1 month later. We reviewed a total of 19 published cases of late-onset traumatic flap dislocations or displacements after LASIK with complete data from 2000 to 2014. Traumatic displacement of corneal flaps after LASIK may occur after blunt injury with specific direction of force to the flap margin, especially tangential one. According to the previous literature, late-onset traumatic flap displacement may happen at any time after LASIK and be caused by various types of injuries. Fortunately, good visual function could mostly be restored with immediate and proper management.

  2. Research on Joint Parameter Inversion for an Integrated Underground Displacement 3D Measuring Sensor

    Directory of Open Access Journals (Sweden)

    Nanying Shentu

    2015-04-01

    Full Text Available Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor.

  3. Evaluation of force degradation characteristics of orthodontic latex elastics in vitro and in vivo.

    Science.gov (United States)

    Wang, Tong; Zhou, Gang; Tan, Xianfeng; Dong, Yaojun

    2007-07-01

    To evaluate the characteristics of force degradation of latex elastics in clinical applications and in vitro studies. Samples of 3/16-inch latex elastics were investigated, and 12 students between the ages of 12 and 15 years were selected for the intermaxillary and intramaxillary tractions. The elastics in the control groups were set in artificial saliva and dry room conditions and were stretched 20 mm. The repeated-measure two-way analysis of variance and nonlinear regression analysis were used to identify statistical significance. Overall, there were statistically significant differences between the different methods and observation intervals. At 24- and 48-hour time intervals, the force decreased during in vivo testing and in artificial saliva (P .05). In intermaxillary traction the percentage of initial force remaining after 48 hours was 61%. In intramaxillary traction and in artificial saliva the percentage of initial force remaining was 71%, and in room conditions 86% of initial force remained. Force degradation of latex elastics was different according to their environmental conditions. There was significantly more force degradation in intermaxillary traction than in intramaxillary traction. The dry room condition caused the least force loss. There were some differences among groups in the different times to start wearing elastics in intermaxillary traction but no significant differences in intramaxillary traction.

  4. Framework for non-coherent interface models at finite displacement jumps and finite strains

    Science.gov (United States)

    Ottosen, Niels Saabye; Ristinmaa, Matti; Mosler, Jörn

    2016-05-01

    This paper deals with a novel constitutive framework suitable for non-coherent interfaces, such as cracks, undergoing large deformations in a geometrically exact setting. For this type of interface, the displacement field shows a jump across the interface. Within the engineering community, so-called cohesive zone models are frequently applied in order to describe non-coherent interfaces. However, for existing models to comply with the restrictions imposed by (a) thermodynamical consistency (e.g., the second law of thermodynamics), (b) balance equations (in particular, balance of angular momentum) and (c) material frame indifference, these models are essentially fiber models, i.e. models where the traction vector is collinear with the displacement jump. This constraints the ability to model shear and, in addition, anisotropic effects are excluded. A novel, extended constitutive framework which is consistent with the above mentioned fundamental physical principles is elaborated in this paper. In addition to the classical tractions associated with a cohesive zone model, the main idea is to consider additional tractions related to membrane-like forces and out-of-plane shear forces acting within the interface. For zero displacement jump, i.e. coherent interfaces, this framework degenerates to existing formulations presented in the literature. For hyperelasticity, the Helmholtz energy of the proposed novel framework depends on the displacement jump as well as on the tangent vectors of the interface with respect to the current configuration - or equivalently - the Helmholtz energy depends on the displacement jump and the surface deformation gradient. It turns out that by defining the Helmholtz energy in terms of the invariants of these variables, all above-mentioned fundamental physical principles are automatically fulfilled. Extensions of the novel framework necessary for material degradation (damage) and plasticity are also covered.

  5. Return after flight : exploring the decision making process of Sudanese war-displaced people by employing an extended version of the theory of reasoned action

    OpenAIRE

    Uffelen, van, J.G.

    2006-01-01

    Research Issues and Approach Forced displacement and the response of the international community is one of the most pressing challenges of contemporary times. Whether in dealing with refugees or internally displaced people the international system has been struggling to prevent forced migration, address its consequences and find ‘durable’ solutions (chapter 1). This study concentrates on repatriation policy and practice, which are considered to lack responsiveness to the needs, initiatives an...

  6. Effect of the walking speed to the lower limb joint angular displacements, joint moments and ground reaction forces during walking in water.

    Science.gov (United States)

    Miyoshi, Tasuku; Shirota, Takashi; Yamamoto, Shin-ichiro; Nakazawa, Kimitaka; Akai, Masami

    2004-06-17

    The purpose of this study was to compare the changes in ground reaction forces (GRF), joint angular displacements (JAD), joint moments (JM) and electromyographic (EMG) activities that occur during walking at various speeds in water and on land. Fifteen healthy adults participated in this study. In the water experiments, the water depth was adjusted so that body weight was reduced by 80%. A video-motion analysis system and waterproof force platform was used to obtain kinematics and kinetics data and to calculate the JMs. Results revealed that (1) the anterior-posterior GRF patterns differed between walking in water and walking on land, whereas the medio-lateral GRF patterns were similar, (2) the JAD patterns of the hip and ankle were similar between water- and land-walking, whereas the range of motion at the knee joint was lower in water than on land, (3) the JMs in all three joints were lower in water than on land throughout the stance phase, and (4) the hip joint extension moment and hip extensor muscle EMG activity were increased as walking speed increase during walking in water. Rehabilitative water-walking exercise could be designed to incorporate large-muscle activities, especially of the lower-limb extensor muscles, through full joint range of motion and minimization of joint moments.

  7. Characteristics of capacitance-micro-displacement for model of complex interior surface of the 3D Taiji ball and its applications

    Science.gov (United States)

    Zhu, Ruo-Gu; Jiang, Kun; Qing, Zhao-Bo; Liu, Yue-Hui; Yan, Jun

    2006-11-01

    Taiji image originated from ancient China. It is not only the Taoism emblem but also the ancient graphic presentation sign to everything origin. It either has a too far-reaching impact on traditional culture of China, or is influencing the development of current natural science. On the basis of analyzing the classical philosophic theory of two-dimensional (2-D) Taiji image, we developed it into the model of complex interior surface-three-dimensional (3-D) Taiji ball, and explored its possible applications. Combining modern mathematics and physics knowledge, we have studied on the physical meaning of 3-D Taiji ball, thus the plane change of original Taiji image is developed into space change which is more close to the real world. The change layers are obvious increased notably, and the amount of information included in this model increases correspondingly. We also realized a special paper 3-D Taiji ball whose surface is coved with metal foil by means of laser manufacture. A new experiment set-up for measuring micro displace has been designed and constituted thus the relation between capacitance and micro displacement for the 3-D Taiji ball has performed. Experimental and theoretical analyses are also finished. This models of 3-D Taiji ball for physical characteristics are the first time set up. Experimental data and fitting curves between capacitance and micro displacement for the special paper Taiji ball coved with metal foil are suggested. It is shown that the special Taiji ball has less leakage capacitance or more strengthen electric field than an ordinary half ball capacitance. Finally their potential applied values are explored.

  8. Displacement in Iraq after 2003: coerced decisions in a time of crisis

    OpenAIRE

    Ali, Ali

    2012-01-01

    This is a refugee-centred study of the decision making process of Iraqis displaced after the\\ud Anglo-American invasion of Iraq in 2003. It investigates the pressures and influences that\\ud affected their decisions as well as who was involved and consulted. In doing so it sheds light\\ud on the under-theorised issue of what it means to be forced into a migration decision. The\\ud meaning of coercion is examined and applied to a forced migration context, considering the\\ud dynamics of cumulative...

  9. Boosted performance of a compression-ignition engine with a displaced piston

    Science.gov (United States)

    Moore, Charles S; Foster, Hampton H

    1936-01-01

    Performance tests were made using a rectangular displacer arranged so that the combustion air was forced through equal passages at either end of the displacer into the vertical-disk combustion chamber of a single-cylinder, four-stroke-cycle compression-ignition test engine. After making tests to determine optimum displacer height, shape, and fuel-spray arrangement, engine-performance tests were made at 1,500 and 2,000 r.p.m. for a range of boost pressures from 0 to 20 inches of mercury and for maximum cylinder pressures up to 1,150 pounds per square inch. The engine operation for boosted conditions was very smooth, there being no combustion shock even at the highest maximum cylinder pressures. Indicated mean effective pressures of 240 pounds per square inch for fuel consumptions of 0.39 pound per horsepower-hour have been readily reproduced during routine testing at 2,000 r.p.m. at a boost pressure of 20 inches of mercury.

  10. Forced vibration analysis of a Timoshenko cracked beam using a continuous model for the crack

    OpenAIRE

    Mahdi Heydari; Alireza Ebrahimi; Mehdi Behzad

    2014-01-01

    In this paper, forced flexural vibration of a cracked beam is studied by using a continuous bilinear model for the displacement field. The effects of shear deformation and rotary inertia are considered in the model. The governing equation of motion for the beam is obtained using the Hamilton principle and based on the proposed displacement field. The equation of motion is given for a general force distribution. Then, the equation of motion has been solved for a concentrated force to present a...

  11. Investigating Efficiency of Time Domain Curve fitters Versus Filtering for Rectification of Displacement Histories Reconstructed from Acceleration Measurements

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Brincker, Rune

    2008-01-01

    Computing displacements of a structure from its measured accelerations has been major concern of some fields of engineering such as earthquake engineering. In vibration engineering also displacements are preferred to acceleration histories occasionally i.e. in the determination of forces applied...... on a structure. In brief the major problem that accompanies reconstruction of true displacement from acceleration record is the unreal drift observed in the double integrated acceleration. Purpose of the present work is to address source of the problem, introduce its treatments, show how they work and compare...

  12. Control of master-slave manipulator using virtual force

    International Nuclear Information System (INIS)

    Kosuge, Kazuhiro; Fukuda, Toshio; Itoh, Tomotaka; Sakamoto, Keizoh; Noma, Yasuo.

    1994-01-01

    We propose a control system for a master-slave manipulator system having a rate-controlled slave manipulator. In this system, the master manipulator is stiffness-controlled in the Cartesian coordinate system, and the slave manipulator is damping-controlled in the Cartesian coordinate system. The desired velocity of the slave arm is given by a displacement of the master arm from a nominal position. The operator feels virtual contact force from the environment because the contact force is proportional to the displacement when the slave arm motion is constrained by the environment. The proposed method is experimentally applied to manipulators with three degrees of freedom. The experimental results illustrate the validity of the proposed system. (author)

  13. HTR-10GT AMBs displacement sensor design

    International Nuclear Information System (INIS)

    Shi Zhengang; Zha Meisheng; Zhao Lei; Sun Zhuo

    2005-01-01

    The 10 MW high temperature gas-cooled test module reactor (HTR-10GT) with the core made of spherical fuel elements was designed and constructed by the Institute of Nuclear and New Energy Technology of Tsinghua University in China. In the HTR-10GT, turbo-compressor and generator rotors are connected by a flexible coupling. The rotors, restricted by actual instruments and working environment, must be supported without any contact and lubrication. Active magnetic bearing (AMB), known as its advantages over the conventional bearings., such as contact-free, no-lubricating and active damping vibration, is the best way to suspend and stabilize the position of rotors of HTR-10GT. Each rotor is suspended by two radial and one axial AMBs. The radial AMB's radial gap is 0.15 mm considering the gap of 0.4 mm between the compressor stator and blades in order to protect the compressor. The control system controls the rotor position to meet the required gaps between rotor and stator through windings current. All the position information concerning radial and axial AMB is generated by sensors for measuring the displacement of the levitated body. Some typical sensors, i.e. eddy current displacement sensor, capacitive displacement sensor, can provide position information, but, quite often, unsatisfactory anti-jamming, which is a key issue for AMB systems near generator and other electric devices in HTR-10GT. Therefore, a kind of new type sensor is designed to measure the radial and axial displacements and the vibration of the rotors. This paper focuses on the design characteristics of the HTR-10GT AMBs displacement sensors and introduction of the related experiments to demonstrate its performance. (authors)

  14. Control, pressure perturbations, displacements, and disruptions in highly elongated tokamak plasmas

    International Nuclear Information System (INIS)

    Marcus, F.B.; Hofmann, F.; Tonetti, G.; Jardin, S.C.; Noll, P.

    1989-06-01

    The control and evolution of highly elongated tokamak plasmas with large growth rates are simulated with the axisymmetric, resistive MHD code TSC in the geometry of the TCV tokamak. Pressure perturbations such as sawteeth and externally programmed displacements create initial velocity perturbations which may be stabilized by low power, rapid response coils inside the passively stabilizing vacuum vessel, together with slower shaping coils outside the vessel. Vertical disruption induced voltages and forces on the rapid coils and vessel are investigated, and a model is proposed for an additional vertical force due to poloidal currents. (author) 6 figs., 1 tab., 26 refs

  15. Displacement measurement using an optoelectronic oscillator with an intra-loop Michelson interferometer.

    Science.gov (United States)

    Lee, Jehyun; Park, Sooyoung; Seo, Dae Han; Yim, Sin Hyuk; Yoon, Seokchan; Cho, D

    2016-09-19

    We report on measurement of small displacements with sub-nanometer precision using an optoelectronic oscillator (OEO) with an intra-loop Michelson interferometer. In comparison with conventional homodyne and heterodyne detection methods, where displacement appears as a power change or a phase shift, respectively, in the OEO detection, the displacement produces a shift in the oscillation frequency. In comparison with typical OEO sensors, where the frequency shift is proportional to the OEO oscillation frequency in radio-frequency domain, the frequency shift in our method with an intra-loop interferometer is proportional to an optical frequency. We constructed a hybrid apparatus and compared characteristics of the OEO and heterodyne detection methods.

  16. Forced Displacement and State Council. The Judge who Had a Wide Range of Arguments but not a Broad Extent of Decisions

    Directory of Open Access Journals (Sweden)

    Miguel Andrés López Martínez

    2014-07-01

    Full Text Available People in forced displacement can receive reparations through the State liability declarations by a judge. Judgment could involve some disadvantages but it is still probably to overcome them if the judge attends experts’ recommendations. Theorists were inspired in unconstitutional statu quo showed by Constitutional Court in T-025 case in 2004. We attempt to identify the proposals that influenced the State liability area and specifically the way in which they changed the frame of administrative judge’s decisions. First, we identified 18 theoretical scape lines, as alternatives to understand in a wider sense the damage, its imputation and reparation in a judicial landscape. Second, we attempt to establish if the State Council was influenced by the theorists’ suggestions, by studying four decisions published from 2004 until 2010. The evidence has shown that the administrative judge was far from the theorists’ proposals, although his attempts to offer better conditions to the victims.

  17. Measuring vulnerability to disaster displacement

    Science.gov (United States)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    Large scale disasters can cause devastating impacts in terms of population displacement. Between 2008 and 2013, on average 27 million people were displaced annually by disasters (Yonetani 2014). After large events such as hurricane Katrina or the Port-au-Prince earthquake, images of inadequate public shelter and concerns about large scale and often inequitable migration have been broadcast around the world. Population displacement can often be one of the most devastating and visible impacts of a natural disaster. Despite the importance of population displacement in disaster events, measures to understand the socio-economic vulnerability of a community often use broad metrics to estimate the total socio-economic risk of an event rather than focusing on the specific impacts that a community faces in a disaster. Population displacement is complex and multi-causal with the physical impact of a disaster interacting with vulnerability arising from the response, environmental issues (e.g., weather), cultural concerns (e.g., expectations of adequate shelter), and many individual factors (e.g., mobility, risk perception). In addition to the complexity of the causes, population displacement is difficult to measure because of the wide variety of different terms and definitions and its multi-dimensional nature. When we speak of severe population displacement, we may refer to a large number of displaced people, an extended length of displacement or associated difficulties such as poor shelter quality, risk of violence and crime in shelter communities, discrimination in aid, a lack of access to employment or other difficulties that can be associated with large scale population displacement. We have completed a thorough review of the literature on disaster population displacement. Research has been conducted on historic events to understand the types of negative impacts associated with population displacement and also the vulnerability of different groups to these impacts. We

  18. Stress and displacement patterns in the craniofacial skeleton with rapid maxillary expansion—a finite element method study

    Directory of Open Access Journals (Sweden)

    J. Priyadarshini

    2017-07-01

    Full Text Available Abstract Background Rapid maxillary expansion (RME, indicated in the treatment of maxillary deficiency directs high forces to maxillary basal bone and to other adjacent skeletal bones. The aim of this study is to (i evaluate stress distribution along craniofacial sutures and (ii study the displacement of various craniofacial structures with rapid maxillary expansion therapy by using a Finite Element model. Methods An analytical model was developed from a dried human skull of a 12 year old male. CT scan images of the skull were taken in axial direction parallel to the F-H plane at 1 mm interval, processed using Mimics software, required portion of the skull was exported into stereo-lithography model. ANSYS software was used to solve the mathematical equation. Contour plots of the displacement and stresses were obtained from the results of the analysis performed. Results At Node 47005, maximum X-displacement was 5.073 mm corresponding to the incisal edge of the upper central incisor. At Node 3971, maximum negative Y-displacement was -0.86 mm which corresponds to the anterior zygomatic arch, indicating posterior movement of craniofacial complex. At Node 32324, maximum negative Z-displacement was -0.92 mm representing the anterior and deepest convex portion of the nasal septum; indicating downward displacement of structures medial to the area of force application. Conclusions Pyramidal displacement of maxilla was evident. Apex of pyramid faced the nasal bone and base was located on the oral side. Posterosuperior part of nasal cavity moved minimally in lateral direction and width of nasal cavity at the floor of the nose increased, there was downward and forward movement of maxilla with a tendency toward posterior rotation. Maximum von Mises stresses were found along midpalatal, pterygomaxillary, nasomaxillary and frontomaxillary sutures.

  19. Airflow and Temperature Distribution in Rooms with Displacement Ventilation

    DEFF Research Database (Denmark)

    Jacobsen, T. V.

    This thesis deals with air flow and temperature distribution in a room ventilated by the displacement principle. The characteristic features of the ventilation system are treated in the whole room but main emphasis is laid on the analysis of the stratified flow region in front of the inlet device....... After a prefatory description of the background and the fundamentals of displacement ventilation the objectives of the current study are specified. The subsequent sections describe the measurements of velocity and temperature profiles carried out in a full scale test room. Based on experimental data...... of measured data is of crucial importance. Qualitatively satisfactory results do not ensure quantitative agreement....

  20. Impact of balancing-side tooth contact on clenching induced mandibular displacements in humans.

    Science.gov (United States)

    Baba, K; Yugami, K; Yaka, T; Ai, M

    2001-08-01

    This study investigated mandibular displacements during clenching in the lateral mandibular position in relation to lateral occlusal relationships. Twelve healthy human subjects (mean=26.7 years) volunteered for this study. Acrylic occlusal devices were fabricated for the lower working-side canine, working-side second molar and balancing-side second molar in order to simulate a dominant canine guidance, working-side interference (WI), balancing-side interference (BI) and bilateral balanced occlusion (BO). Vertical displacements of the mandible were recorded by linear variable differential transformers during submaximal clenching in the right lateral position. The four experimental occlusal conditions were revealed to have a significant effect on mandibular displacement patterns (ANOVA, P experimental conditions. These results suggest that the nature of reaction forces at the temporomandibular (TM) joints caused by the elevation of the mandible varies in a predictable manner depending upon lateral occlusal relationships.

  1. Improved anchoring of SSS with vacuum barrier to avoid displacement

    CERN Document Server

    Capatina, O; Foreste, A; Parma, V; Renaglia, T; Quesnel, J

    2009-01-01

    As presented in the previous speech, the incident in sector 3-4 of the LHC caused a high pressure build-up inside the cryostat insulation vacuum resulting in high longitudinal forces acting on the insulation vacuum barriers. This resulted in braking floor and floor fixations of the SSS with vacuum barrier. The strategy of improving anchoring of SSS with vacuum barrier to avoid displacement is presented and discussed.

  2. ASSESSMENT OF THE RELEVANCE OF DISPLACEMENT BASED DESIGN METHODS/CRITERIA TO NUCLEAR PLANT STRUCTURES

    International Nuclear Information System (INIS)

    HOFMAYER, C.; MILLER, C.; WANG, Y.; COSTELLO, J.

    2001-01-01

    Revisions to the USNRC Regulatory Guides and Standard Review Plan Sections devoted to earthquake engineering practice are currently in process. The intent is to reflect changes in engineering practice that have evolved in the twenty years that have passed since those criteria were originally published. Additionally, field observations of the effects of the Northridge (1994) and Kobe (1995) earthquakes have inspired some reassessment in the technical community about certain aspects of design practice. In particular, questions have arisen about the effectiveness of basing earthquake resistant designs on resistance to seismic forces and, then evaluating tolerability of the expected displacements. Therefore, a research effort was undertaken to examine the implications for NRC's seismic practice of the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The results of the NRC sponsored research on this subject are reported in this paper. A slow trend toward the utilization of displacement based methods for design was noted. However, there is a more rapid trend toward the use of displacement based methods for seismic evaluation of existing facilities. A document known as FEMA 273, has been developed and is being used as the basis for the design of modifications to enhance the seismic capability of existing non-nuclear facilities. The research concluded that displacement based methods, such as given in FEMA 273, may be useful for seismic margin studies of existing nuclear power stations. They are unlikely to be useful for the basic design of new stations since nuclear power stations are designed to remain elastic during a seismic event. They could, however, be useful for estimating the margins associated with that design

  3. Resonant neutron-induced atomic displacements

    Energy Technology Data Exchange (ETDEWEB)

    Elmaghraby, Elsayed K., E-mail: e.m.k.elmaghraby@gmail.com

    2017-05-01

    Highlights: • Neutron induced atomic displacements was investigated based on scattering of energy of neutron. • Model for cascade function (multiplication of displacements with increasing energy transfer) was proposed and justified. • Parameterizations for the dpa induced in all elements were performed. • Table containing all necessary parameters to calculate the displacement density induced by neutron is given. • Contribution of non resonance displacement and resonant-neutron induced displacements are distinguished. - Abstract: A model for displacement cascade function was modified to account for the continuous variation of displacement density in the material in response to neutron exposure. The model is based on the Gaussian distribution of displacement energies of atoms in a material. Analytical treatment for moderated epithermal neutron field was given in which the displacement density was divided into two terms, discrete-resonance term and continuum term. Calculation are done for all isotopes using ENDF/B VII.1 data files and temperature dependent cross section library. Weighted elemental values were reported a fitting was performed to obtain energy-dependent formula of displacement density and reduce the number of parameters. Results relevant the present specification of the cascade function are tabulated for each element to enable calculation of displacement density at any value of displacement energy in the between 5 eV and 55 eV.

  4. Electrical Stimulation Frequency and Skeletal Muscle Characteristics: Effects on Force and Fatigue

    Directory of Open Access Journals (Sweden)

    Maria Vromans

    2017-12-01

    Full Text Available This investigation aimed to determine the force and muscle surface electromyography (EMG responses to different frequencies of electrical stimulation (ES in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB and vastus lateralis (VL when activated by ES at three frequencies (10, 35, and 50Hz. Ten healthy adults (mean age: 23.2 ± 3.0 years were recruited; participants signed an IRB approved consent form prior to participation. Protocols were developed to 1 identify initial ES current intensity required to generate the 25% maximal voluntary contraction (MVC at each ES frequency and 2 evaluate changes in force and EMG activity during ES-induced contraction at each frequency while progressing towards fatigue. For both muscles, stimulation at 10Hz required higher current intensity of ES to generate the initial force. There was a significant decline in force in response to ES-induced fatigue for all frequencies and for both muscles (p<0.05. However, the EMG response was not consistent between muscles. During the progression towards fatigue, the APB displayed an initial drop in force followed by an increase in EMG activity and the VL displayed a decrease in EMG activity for all frequencies. Overall, it appeared that there were some significant interactions between muscle size and fiber composition during progression towards fatigue for different ES frequencies. It could be postulated that muscle characteristics (size and fiber composition should be considered when evaluating progression towards fatigue as EMG and force responses are not consistent between muscles.

  5. Coulomb displacement energy of the f sub(7/2) state of the 48Ca

    International Nuclear Information System (INIS)

    Sato, Hiroshi.

    1979-11-01

    The Coulomb displacement energy of the T = 4, J = 0 state of the 48 Ca is analyzed. Modifying a previous method of the calculation of the core polarization correction, it is found that the charge symmetry breaking force, which is introduced previously so as to help explain the Nolen-Schiffer anomaly of the T = 1/2 system, is also needed in this system, while there still exists an ambituity in the type of the force. (author)

  6. Multistage Force Amplification of Piezoelectric Stacks

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)

    2015-01-01

    Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

  7. Discharge switch driving by Lorentz force and its characteristics

    International Nuclear Information System (INIS)

    Inoue, Kunikazu; Hasegawa, Mitsuo; Ueno, Isao

    1999-01-01

    Our newly developed 'Rotary-Arc mode Discharge Switch' have featured longer life expectancy and lower inductance-wise by extremely minimizing the insulation deterioration and consumable main electrode through installation of permanent magnet, simplified construction and careful attention on the demagnetization. Resultantly, highly efficient and larger capacitive discharge switch have been available at such economical cost. In addition, by having derived an experimental formula for the driving speed of the arc, the required design parameters of the discharge switch have been determined, and then it has been well noted that any affections of electro-magnetic Lorentz force toward the starting characteristics have been negligible small. All these have made it possible to materialize such discharge switch which will satisfy the required conditions. (author)

  8. Off-Axis Gaussian Beams with Random Displacement in Atmospheric Turbulence

    Directory of Open Access Journals (Sweden)

    Yahya Baykal

    2006-10-01

    Full Text Available Our recent work in which we study the propagation of the general Hermite-sinusoidal-Gaussian laser beams in wireless broadband access telecommunication systems is elaborated in this paper to cover the special case of an off-axis Gaussian beam. We mainly investigate the propagation characteristics in atmospheric turbulence of an off-axis Gaussian beam possessing Gaussian distributed random displacement parameters. Our interest is to search for different types of laser beams that will improve the performance of a wireless broadband access system when atmospheric turbulence is considered. Our formulation is based on the basic solution of the second order mutual coherence function evaluated at the receiver plane. For fixed turbulence strength, the coherence length calculated at the receiver plane is found to decrease as the variance of the random displacement is increased. It is shown that as the turbulence becomes stronger, coherence lengths due to off-axis Gaussian beams tend to approach the same value, irrespective of the variance of the random displacement. As expected, the beam spreading is found to be pronounced for larger variance of displacement parameter. Average intensity profiles when atmospheric turbulence is present are plotted for different values of the variance of the random displacement parameter of the off-axis Gaussian beam.

  9. Characteristics of strongly-forced turbulent jets and non-premixed jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarasimhan, K.; Ezekoye, O.A. [University of Texas at Austin, Department of Mechanical Engineering, Austin, TX (United States); Clemens, N.T. [University of Texas at Austin, Department of Aerospace Engineering and Engineering Mechanics, Austin, TX (United States)

    2006-10-15

    Previous researchers have demonstrated that strong pulsations of the fuel flow rate can significantly reduce the flame length and luminosity of laminar/transitional non-premixed jet flames. The physical mechanisms responsible for these changes are investigated experimentally in acoustically-forced jet flows where the peak velocity fluctuations are up to eight times the mean flow velocity. Both reacting and non-reacting flows were studied and Reynolds numbers, based on the mean flow properties, ranged from 800 to 10,000 (corresponding to peak Reynolds numbers of 1,450-23,000), and forcing frequencies ranged from 290 to 1,140 Hz. Both the first and second organ-pipe resonance modes of the fuel delivery tube were excited to obtain these frequencies. An analysis of the acoustic forcing characteristics within the resonance tube is provided in order to understand the source of the high amplitude forcing. Flow visualization of jets with first resonant forcing confirms the presence of large-scale coherent vortices and strong reverse flow near the exit of the fuel tube. With second-resonant forcing, however, vortices are not emitted from the tube as they are drawn back into the fuel tube before they can fully form. Increased fine-scale turbulence is associated with both resonant cases, but particularly at second resonance. The power spectra of the velocity fluctuations for a resonantly pulsed jet show the presence of an inertial subrange indicating that the flow becomes fully turbulent even for mean-Reynolds-number jets that are nominally laminar. It is shown that these pulsed jet flows exhibit strong similarities to synthetic jets and that the Strouhal number, based on the maximum velocity at the fuel tube exit, is the dominant parameter for scaling these flows. The Strouhal number determines the downstream location where the coherent vortices breakdown, and is found to provide better collapse of flame length data (both current and previous) than other parameters that have

  10. Researching Refugees and Forced Migration in the Eastern/Horn of Africa

    DEFF Research Database (Denmark)

    Owiso, Michael; Schmidt, Johannes Dragsbæk

    Refugees, forced migration and human displacement is growing across the globe and increasingly a growing body of scholarly literature has tried to capture the most important implications of this disturbing trend. Similarly, studies in Eastern and Horn of Africa have dramatically increased as a re...... on the region is however lacking. This paper traces the evolution of refugees and forced migration, identifies the issues and trends, the dominant conceptualizations, policy responses and uncovers the gaps which form suggestions for future studies....... as a result of the complex and dynamic nature of displacement. While this is the case, researching refugees and forced migration remains challenging as evidenced in historical, political, policy, sociological and anthropological studies. A systematic categorization of this academic literature focusing...

  11. Job Displacement and Crime

    DEFF Research Database (Denmark)

    Bennett, Patrick; Ouazad, Amine

    theory of crime. Marital dissolution is more likely post-displacement, and we find small intra-family externalities of adult displacement on younger family members’ crime. The impact of displacement on crime is stronger in municipalities with higher capital and labor income inequalities....

  12. Inertia effects on the rigid displacement approximation of tokamak plasma vertical motion

    International Nuclear Information System (INIS)

    Carrera, R.; Khayrutdinov, R.R.; Azizov, E.A.; Montalvo, E.; Dong, J.Q.

    1991-01-01

    Elongated plasmas in tokamaks are unstable to axisymmetric vertical displacements. The vacuum vessel and passive conductors can stabilize the plasma motion in the short time scale. For stabilization of the plasma movement in the long time scale an active feedback control system is required. A widely used method of plasma stability analysis uses the Rigid Displacement Model (RDM) of plasma behavior. In the RDM it is assumed that the plasma displacement is small and usually plasma inertia effects are neglected. In addition, it is considered that no changes in plasma shape, plasma current, and plasma current profile take place throughout the plasma motion. It has been demonstrated that the massless-filament approximation (instantaneous force-balance) accurately reproduces the unstable root of the passive stabilization problem. Then, on the basis that the instantaneous force-balance approximation is correct in the passive stabilization analysis, the massless approximation is utilized also in the study of the plasma vertical stabilization by active feedback. The authors show here that the RDM (without mass effects included) does not provide correct stability results for a tokamak configuration (plasma column, passive conductors, and feedback control coils). Therefore, it is concluded that inertia effects have to be retained in the RDM system of equations. It is shown analytically and numerically that stability diagrams with and without plasma-mass corrections differ significantly. When inertia effects are included, the stability region is more restricted than obtained in the massless approximation

  13. Displacement sensor for measurement of fuel rod elongation in the LOFT reactors

    International Nuclear Information System (INIS)

    Billeter, T.R.

    1979-09-01

    Qualification tests conducted for a period of 700 hours of each of three displacement measuring (LVDT) sensors confirmed applicability of the design for use in the Loss-of-Fluid-Test (LOFT) reactor. Operationally, the sensor satisfies all specified requirements for LOFT. Even for imposed temperature transients at rates up to 100 0 F/s, the indicated displacement remained within the allowed maximum error band of +- 10% of reading. The 0.6-inch O.D. by 5.5-inch long sensor exhibited a linearly related signal output variation for displacement variations of up to 1-inch range. Long term operation at temperatures of 100 0 F to 800 0 F caused no perceptible permanent change of operating characteristics

  14. Public policy for victims of forced displacement in the city of Medellín: a synthesis of interorganizational relationships from a policy network perspective

    Directory of Open Access Journals (Sweden)

    Jonathan Alejandro Murcia

    2016-11-01

    Full Text Available This article seeks to synthetise the interorganisational relationships that have developed in Public Policy in relation with victims of forced displacement in the Municipality of Medellin. Using the Public Policy Networks approach and Inter-organisational theory, it focuses on scenarios where such relationships occurred, on the attributes, positions and roles of the organisations, on the types of relationships, exchanges and resources. To achieve the objectives, Social Network Analysis as methodological strategy and qualitative strategies were used to understand the organizations’ perceptions of their relationships in the policy process. This study permitted to understand the structure and dynamics of the network, and enhanced different modalities in the participation of organizations in terms of frequency, changes in their roles, power relations, conflicting and cooperative relations, among other factors.

  15. Characteristics of U.S. Air Force Members with Stepfamily and Divorce Conditions in Substance Abuse Services

    National Research Council Canada - National Science Library

    Miller, Carl

    2002-01-01

    This study was an attempt to describe the characteristics of U.S. Air Force (USAF) members with stepfamily and divorce conditions who had received services from USAF substance abuse treatment programs...

  16. Study of electroosmosis-driven two-liquid displacement flow in a microcapillary

    International Nuclear Information System (INIS)

    Gan, H Y; Yang, C; Wan, S Y M; Lim, G C; Lam, Y C

    2006-01-01

    Multi-liquid flow, such as one liquid displacing another liquid, is frequently encountered in practice. This can be achieved by electroosmotic (EO) pumping, which has its own unique characteristics and advantages. This investigation is on EO-driven, two-liquid displacement flow in a microcapillary. A theoretical model was developed to take into consideration the axial step change of velocity flow fields at the time-dependent liquid/liquid interface, continuity requirement, and induced local pressure gradients. The electrical current monitoring method was employed to measure the flowrate and subsequently determine the capillary zeta potentials which are required for the model prediction. The nonlinear change of the electrical current with time under a constant applied voltage was observed during the displacement process. The theoretical and experimental results validated the hypothesis that the non-uniform zeta potential and electric field induce local pressure gradients in the two different liquids. Our experimental results indicated that the time of displacement, and thus the flow velocity, is found to be dependent on the displacing flow direction, which has hitherto not been reported in the literature. The underlying mechanisms were postulated, but demand further investigation

  17. Characteristics of the Gamow-Teller Force in the β- Decay of 40Zr98

    International Nuclear Information System (INIS)

    Raden Oktova

    2002-01-01

    The characteristics of the β - decay force for the Gamow-Teller transition in the p-h and the p-p channels in the heavy neutron-rich nucleus 40 Zr 98 have been studied. The ground state single-particle levels in the parent nucleus were calculated self-consistently using the Fayans energy-density functional, and from them the quasi-particle basis was obtained using the BCS model. The residual charge-changing force responsible for the β - transition was taken as having a zero-range (a delta function); in the p-h channel the spin-isospin exchange → σ 1 . → σ 2 → τ 1 . → τ 2 term in the Migdal-Larkin force was used, and that in the p-p channel was a constant. The method employed was the proton-neutron QRPA (pnQRPA). The results show that the proton-neutron pairing p-p force in the Gamow-Teller decay is negligible for the nucleus considered. The value of the p-h force obtained is g ' = 0.735, slightly larger than the standard value of g ' = 0.7 commonly used for stable nuclei. (author)

  18. Fourier-based integration of quasi-periodic gait accelerations for drift-free displacement estimation using inertial sensors.

    Science.gov (United States)

    Sabatini, Angelo Maria; Ligorio, Gabriele; Mannini, Andrea

    2015-11-23

    In biomechanical studies Optical Motion Capture Systems (OMCS) are considered the gold standard for determining the orientation and the position (pose) of an object in a global reference frame. However, the use of OMCS can be difficult, which has prompted research on alternative sensing technologies, such as body-worn inertial sensors. We developed a drift-free method to estimate the three-dimensional (3D) displacement of a body part during cyclical motions using body-worn inertial sensors. We performed the Fourier analysis of the stride-by-stride estimates of the linear acceleration, which were obtained by transposing the specific forces measured by the tri-axial accelerometer into the global frame using a quaternion-based orientation estimation algorithm and detecting when each stride began using a gait-segmentation algorithm. The time integration was performed analytically using the Fourier series coefficients; the inverse Fourier series was then taken for reconstructing the displacement over each single stride. The displacement traces were concatenated and spline-interpolated to obtain the entire trace. The method was applied to estimate the motion of the lower trunk of healthy subjects that walked on a treadmill and it was validated using OMCS reference 3D displacement data; different approaches were tested for transposing the measured specific force into the global frame, segmenting the gait and performing time integration (numerically and analytically). The width of the limits of agreements were computed between each tested method and the OMCS reference method for each anatomical direction: Medio-Lateral (ML), VerTical (VT) and Antero-Posterior (AP); using the proposed method, it was observed that the vertical component of displacement (VT) was within ±4 mm (±1.96 standard deviation) of OMCS data and each component of horizontal displacement (ML and AP) was within ±9 mm of OMCS data. Fourier harmonic analysis was applied to model stride-by-stride linear

  19. Return after flight : exploring the decision making process of Sudanese war-displaced people by employing an extended version of the theory of reasoned action

    NARCIS (Netherlands)

    Uffelen, van J.G.

    2006-01-01

    Research Issues and Approach Forced displacement and the response of the international community is one of the most pressing challenges of contemporary times. Whether in dealing with refugees or internally displaced people the international system has been struggling to prevent

  20. Rotational displacement skills in rhesus macaques (Macaca mulatta).

    Science.gov (United States)

    Hughes, Kelly D; Santos, Laurie R

    2012-11-01

    Rotational displacement tasks, in which participants must track an object at a hiding location within an array while the array rotates, exhibit a puzzling developmental pattern in humans. Human children take an unusually long time to master this task and tend to solve rotational problems through the use of nongeometric features or landmarks as opposed to other kinds of spatial cues. We investigated whether these developmental characteristics are unique to humans by testing rotational displacement skills in a monkey species, the rhesus macaque (Macaca mulatta), using a looking-time method. Monkeys first saw food hidden in two differently colored boxes within an array. The array was then rotated 180° and the boxes reopened to reveal the food in an expected or unexpected location. Our first two experiments explored the developmental time-course of performance on this rotational displacement task. We found that adult macaques looked longer at the unexpected event, but such performance was not mirrored in younger-aged macaques. In a third study, we systematically varied featural information and visible access to the array to investigate which strategies adult macaques used in solving rotational displacements. Our results show that adult macaques need both sets of information to solve the task. Taken together, these results suggest both similarities and differences in mechanisms by which human and nonhuman primates develop this spatial skill.

  1. Fall with linear drag and Wien's displacement law: approximate solution and Lambert function

    International Nuclear Information System (INIS)

    Vial, Alexandre

    2012-01-01

    We present an approximate solution for the downward time of travel in the case of a mass falling with a linear drag force. We show how a quasi-analytical solution implying the Lambert function can be found. We also show that solving the previous problem is equivalent to the search for Wien's displacement law. These results can be of interest for undergraduate students, as they show that some transcendental equations found in physics may be solved without purely numerical methods. Moreover, as will be seen in the case of Wien's displacement law, solutions based on series expansion can be very accurate even with few terms. (paper)

  2. Traumatic corneal flap displacement after laser in situ keratomileusis (LASIK

    Directory of Open Access Journals (Sweden)

    Tsai TH

    2017-04-01

    Full Text Available Tsung-Han Tsai,1 Kai-Ling Peng,1 Chien-Jen Lin2 1Department of Ophthalmology, 2Department of Radiology, Chi Mei Medical Center, Tainan, Taiwan Background: Laser in situ keratomileusis (LASIK is the most common and popular procedure performed for the correction of refractive errors in the last two decades. We report a case of traumatic flap displacement with flap folding which occurred 3 years after LASIK was performed. Previous literature suggests that vision prognosis would be closely related to proper and prompt management of traumatic flap displacement with flap folding 3 years after LASIK.Case presentation: A 23-year-old female presented to our hospital who had undergone uneventful LASIK in both eyes 3 years prior. Unfortunately, she had suffered a blunt trauma in her right eye in a car accident. A late onset of corneal flap displacement was found with upper and lower portion of the flap being folded inside the corneal bed. Surgical intervention for debridement with subsequent reposition of corneal flap was performed as soon as possible in the operating room. A bandage contact lens was placed, and topical antibiotic and corticosteroids were given postoperatively. Two days after the operation, the displaced corneal flap was found to be well attached smoothly on the corneal bed without folds. The best-corrected visual acuity was 6/6 with refraction of −0.75 D to 1.0 D ×175° in her right eye 1 month later.Literature review: We reviewed a total of 19 published cases of late-onset traumatic flap dislocations or displacements after LASIK with complete data from 2000 to 2014.Conclusion: Traumatic displacement of corneal flaps after LASIK may occur after blunt injury with specific direction of force to the flap margin, especially tangential one. According to the previous literature, late-onset traumatic flap displacement may happen at any time after LASIK and be caused by various types of injuries. Fortunately, good visual function could

  3. Predisplacement and postdisplacement factors associated with mental health of refugees and internally displaced persons: a meta-analysis.

    Science.gov (United States)

    Porter, Matthew; Haslam, Nick

    2005-08-03

    The global refugee crisis requires that researchers, policymakers, and clinicians comprehend the magnitude of the psychological consequences of forced displacement and the factors that moderate them. To date, no empirical synthesis of research on these issues has been undertaken. To meta-analytically establish the extent of compromised mental health among refugees (including internally displaced persons, asylum seekers, and stateless persons) using a worldwide study sample. Potential moderators of mental health outcomes were examined, including enduring contextual variables (eg, postdisplacement accommodation and economic opportunity) and refugee characteristics. Published studies (1959-2002) were obtained using broad searches of computerized databases (PsycINFO and PILOTS), manual searches of reference lists, and interviews with prominent authors. Studies were selected if they investigated a refugee group and at least 1 nonrefugee comparison group and reported 1 or more quantitative group comparison on measures of psychopathology. Fifty-six reports met inclusion criteria (4.4% of identified reports), yielding 59 independent comparisons and including 67,294 participants (22,221 refugees and 45,073 nonrefugees). Data on study and report characteristics, study participant characteristics, and statistical outcomes were extracted using a coding manual and subjected to blind recoding, which indicated high reliability. Methodological quality information was coded to assess potential sources of bias. Effect size estimates for the refugee-nonrefugee comparisons were averaged across psychopathology measures within studies and weighted by sample size. The weighted mean effect size was 0.41 (SD, 0.02; range, -1.36 to 2.91 [SE, 0.01]), indicating that refugees had moderately poorer outcomes. Postdisplacement conditions moderated mental health outcomes. Worse outcomes were observed for refugees living in institutional accommodation, experiencing restricted economic opportunity

  4. Mechanical design and force calibration of dual-axis micromechanical probe for friction force microscopy

    International Nuclear Information System (INIS)

    Fukuzawa, Kenji; Terada, Satoshi; Shikida, Mitsuhiro; Amakawa, Hiroaki; Zhang, Hedong; Mitsuya, Yasunaga

    2007-01-01

    A dual-axis micromechanical probe that combines a double cantilever and torsion beams is presented. This probe can reduce the mechanical cross-talk between the lateral and vertical force detections. In addition, dual-axis forces can be detected by measuring the dual-axis displacement of the probe end using the optical lever-based method used in conventional friction force microscopes (FFMs). In this paper, the mechanical design of the probe, the details of the fabrication method, FFM performance, and calibration of the friction force are discussed. The mechanical design and the microfabrication method for probes that can provide a force resolution of the order of 1 nN without mechanical cross-talk are presented. Calibration of the lateral force signal is possible by using the relationship between the lateral force and the piezodisplacement at the onset of the probe scanning. The micromechanical probe enables simultaneous and independent detection of atomic and friction forces. This leads to accurate investigation of nanotribological phenomena and visualization of the distribution of the friction properties, which helps the identification of the material properties

  5. Electric sail elliptic displaced orbits with advanced thrust model

    Science.gov (United States)

    Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

    2017-09-01

    This paper analyzes the performance of an Electric Solar Wind Sail for generating and maintaining an elliptic, heliocentric, displaced non-Keplerian orbit. In this sense, this paper extends and completes recent studies regarding the performances of an Electric Solar Wind Sail that covers a circular, heliocentric, displaced orbit of given characteristics. The paper presents the general equations that describe the elliptic orbit maintenance in terms of both spacecraft attitude and performance requirements, when a refined thrust model (recently proposed for the preliminary mission design) is taken into account. In particular, the paper also discusses some practical applications on particular mission scenarios in which an analytic solution of the governing equations has been found.

  6. A Vision-Based Approach for Estimating Contact Forces: Applications to Robot-Assisted Surgery

    Directory of Open Access Journals (Sweden)

    C. W. Kennedy

    2005-01-01

    Full Text Available The primary goal of this paper is to provide force feedback to the user using vision-based techniques. The approach presented in this paper can be used to provide force feedback to the surgeon for robot-assisted procedures. As proof of concept, we have developed a linear elastic finite element model (FEM of a rubber membrane whereby the nodal displacements of the membrane points are measured using vision. These nodal displacements are the input into our finite element model. In the first experiment, we track the deformation of the membrane in real-time through stereovision and compare it with the actual deformation computed through forward kinematics of the robot arm. On the basis of accurate deformation estimation through vision, we test the physical model of a membrane developed through finite element techniques. The FEM model accurately reflects the interaction forces on the user console when the interaction forces of the robot arm with the membrane are compared with those experienced by the surgeon on the console through the force feedback device. In the second experiment, the PHANToM haptic interface device is used to control the Mitsubishi PA-10 robot arm and interact with the membrane in real-time. Image data obtained through vision of the deformation of the membrane is used as the displacement input for the FEM model to compute the local interaction forces which are then displayed on the user console for providing force feedback and hence closing the loop.

  7. Effect of rheological characteristics and technology of application of a viscoelastic separator on its displacing ability

    Energy Technology Data Exchange (ETDEWEB)

    Gnibidin, V N

    1980-01-01

    Presented are the results of industrial tests of the displacing ability of a viscoelastic separator, obtained by mixing a clay suspension and an aqueous solution of polyacrylamide. It is established that the displacing ability of the viscoelastic separator is determined mainly by the value of the final normal stresses sigma /SUB f/ . The greatest effect from the use of this separator is achieved with sigma /SUB f/ of at least 600 dyne/cm/sup 2/ and a rate of movement of not more than 0.5 m/sec.

  8. On Newton-Raphson formulation and algorithm for displacement based structural dynamics problem with quadratic damping nonlinearity

    Directory of Open Access Journals (Sweden)

    Koh Kim Jie

    2017-01-01

    Full Text Available Quadratic damping nonlinearity is challenging for displacement based structural dynamics problem as the problem is nonlinear in time derivative of the primitive variable. For such nonlinearity, the formulation of tangent stiffness matrix is not lucid in the literature. Consequently, ambiguity related to kinematics update arises when implementing the time integration-iterative algorithm. In present work, an Euler-Bernoulli beam vibration problem with quadratic damping nonlinearity is addressed as the main source of quadratic damping nonlinearity arises from drag force estimation, which is generally valid only for slender structures. Employing Newton-Raphson formulation, tangent stiffness components associated with quadratic damping nonlinearity requires velocity input for evaluation purpose. For this reason, two mathematically equivalent algorithm structures with different kinematics arrangement are tested. Both algorithm structures result in the same accuracy and convergence characteristic of solution.

  9. Radiation-Force Assisted Targeting Facilitates Ultrasonic Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Shukui Zhao

    2004-07-01

    Full Text Available Ultrasonic molecular imaging employs contrast agents, such as microbubbles, nanoparticles, or liposomes, coated with ligands specific for receptors expressed on cells at sites of angiogenesis, inflammation, or thrombus. Concentration of these highly echogenic contrast agents at a target site enhances the ultrasound signal received from that site, promoting ultrasonic detection and analysis of disease states. In this article, we show that acoustic radiation force can be used to displace targeted contrast agents to a vessel wall, greatly increasing the number of agents binding to available surface receptors. We provide a theoretical evaluation of the magnitude of acoustic radiation force and show that it is possible to displace micron-sized agents physiologically relevant distances. Following this, we show in a series of experiments that acoustic radiation force can enhance the binding of targeted agents: The number of biotinylated microbubbles adherent to a synthetic vessel coated with avidin increases as much as 20-fold when acoustic radiation force is applied; the adhesion of contrast agents targeted to αvβ3 expressed on human umbilical vein endothelial cells increases 27-fold within a mimetic vessel when radiation force is applied; and finally, the image signal-to-noise ratio in a phantom vessel increases up to 25 dB using a combination of radiation force and a targeted contrast agent, over use of a targeted contrast agent alone.

  10. A complex social-ecological disaster: Environmentally induced forced migration.

    Science.gov (United States)

    Rechkemmer, Andreas; O'Connor, Ashley; Rai, Abha; Decker Sparks, Jessica L; Mudliar, Pranietha; Shultz, James M

    2016-01-01

    In the 21 st century, global issues are increasingly characterized by inter-connectedness and complexity. Global environmental change, and climate change in particular, has become a powerful driver and catalyst of forced migration and internal displacement of people. Environmental migrants may far outnumber any other group of displaced people and refugees in the years to come. Deeper scientific integration, especially across the social sciences, is a prerequisite to tackle this issue.

  11. Distribution characteristics of radon and its progeny in blind roadway with forced ventilation

    International Nuclear Information System (INIS)

    Ye Yongjun; Zhou Xinghuo; Li Xiangyang; Zhong Yongming; Liu Dong; Ding Dexin

    2012-01-01

    The blind roadway is not only the important workplaces, but also is important site of radon and its progeny generating and gathering, it is an important guiding significance for ventilation protection design to study distribution characteristics of radon and its progeny in blind roadway. Therefore, at first, the paper expounded the mathematical relationship between radon activity concentration with alpha potential concentration of radon progeny. Then, analyzed the sources of radon and its progeny, and established mathematical calculation model of Distribution characteristics of radon and its progeny in blind roadway with forced ventilation, respectively. Finally, using mathematical calculation models to analyze the influence law of multiple factors. (authors)

  12. A two dimensional fibre reinforced micropolar thermoelastic problem for a half-space subjected to mechanical force

    Directory of Open Access Journals (Sweden)

    Ailawalia Praveen

    2015-01-01

    Full Text Available The purpose of this paper is to study the two dimensional deformation of fibre reinforced micropolar thermoelastic medium in the context of Green-Lindsay theory of thermoelasticity. A mechanical force is applied along the interface of fluid half space and fibre reinforced micropolar thermoelastic half space. The normal mode analysis has been applied to obtain the exact expressions for displacement component, force stress, temperature distribution and tangential couple stress. The effect of anisotropy and micropolarity on the displacement component, force stress, temperature distribution and tangential couple stress has been depicted graphically.

  13. Experimental study of the pressure characteristics in the Stirling refrigerator

    International Nuclear Information System (INIS)

    Hong, Yong Ju; Park, Seong Je; Kim, Hyo Bong; Koh, Deuk Yong

    2001-01-01

    The linear compressor have been widely used for pressure wave generation in the Stirling cryocooler and Stirling type pulse tube cryocooler for tactical purpose. The linear compressor has small and compact structure, and long life due to having non-contact sealing mechanism and the pressure drop through regenerator was ver important role in the motion of displacer in the expander of the Stirling cryocooler. In this study, the characteristic of the linear compressor and the pressure drop through regenerator in the expander was experimentally investigated. The results show resonance of the compressor is very important to get maximum performance and the gas spring force in the compression space of the compressor has effect on the characteristic of resonance and the results show the pressure drop through regenerator is very small than operating pressure change

  14. Investigation on forces in frictional kinematic pairs to assess their influence on shock absorber characteristics

    Directory of Open Access Journals (Sweden)

    Janusz GARDULSKI

    2008-01-01

    Full Text Available In telescopic shock absorbers there are two kinematic pairs where dry,semi-dry or fluid friction is most likely to occur. Higher values of friction forces are noted in piston rod-slideway pair due to its sealing function and consequently worse lubricating conditions. The aim of the tests was to assess the influence of forces occurring in frictional kinematic pairs on damping characteristics of shock absorbers. The tests were performed on new and fluid-free shock absorbers for various working strokes and various extortion frequencies.

  15. Force characteristic analysis of a magnetic gravity compensator with annular magnet array for magnetic levitation positioning system

    Science.gov (United States)

    Zhou, Yiheng; Kou, Baoquan; Liu, Peng; Zhang, He; Xing, Feng; Yang, Xiaobao

    2018-05-01

    Magnetic levitation positioning system (MLPS) is considered to be the state of the art in inspection and manufacturing systems in vacuum. In this paper, a magnetic gravity compensator with annular magnet array (AMA-MGC) for MLPS is proposed. Benefiting from the double-layer annular Halbach magnet array on the stator, the proposed AMA-MGC possesses the advantages of symmetrical force, high force density and small force fluctuation. Firstly, the basic structure and operation principle of the AMA-MGC are introduced. Secondly, the basic characteristics of the AMA-MGC such as magnetic field distribution, levitation force, parasitic force and parasitic torque are analyzed by the three-dimensional finite element analysis (3-D FEA). Thirdly, the influence of structural parameters on force density and force fluctuation is investigated, which is conductive to the design and optimization of the AMA-MGC. Finally, a prototype of the AMA-MGC is constructed, and the experiment shows good agreement with the 3-D FEA results.

  16. Inductive displacement sensors with a notch filter for an active magnetic bearing system.

    Science.gov (United States)

    Chen, Seng-Chi; Le, Dinh-Kha; Nguyen, Van-Sum

    2014-07-15

    Active magnetic bearing (AMB) systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and axial movement of the suspended object. In a high-speed rotating machine equipped with an AMB, the rotor bending modes may be limited to the operating range. The natural frequencies of the rotor can cause instability. Thus, notch filters are a useful circuit for stabilizing the system. In addition, commercial displacement sensors are sometimes not suitable for AMB design, and cannot filter the noise caused by the natural frequencies of rotor. Hence, implementing displacement sensors based on the AMB structure is necessary to eliminate noises caused by natural frequency disturbances. The displacement sensor must be highly sensitive in the desired working range, and also exhibit a low interference noise, high stability, and low cost. In this study, we used the differential inductive sensor head and lock-in amplifier for synchronous demodulation. In addition, an active low-pass filter and a notch filter were used to eliminate disturbances, which caused by natural frequencies. As a consequence, the inductive displacement sensor achieved satisfactory linearity, high sensitivity, and disturbance elimination. This sensor can be easily produced for AMB applications. A prototype of these displacement sensors was built and tested.

  17. Forced Migration in the Middle East: The Palestinian and Syrian Refugee Experience

    Directory of Open Access Journals (Sweden)

    Meltem YNCE YENILMEZ

    2016-11-01

    Full Text Available Forced migration in the Middle East has a long history, going back to, at least, the early days of the 20th century. This paper looks at the experience of two populations, the Palestinian refugees, who experienced their initial displacement in the mid-20th century, and the current day growing population of Syrian refugees. This latter group constitutes the largest group of displaced people since the Second World War. This paper uses the experience of both of these groups to explore the impact that forced migration has had on the host countries and the region at large. It looks at the economic, cultural and political impact of forced migration and concludes that, in the long-term, forced migration, although extremely disruptive to all involved, has a net benefit on the host countries. It also explores lack of regional coping mechanisms, and proposes that the terms “crisis” and “guests” should be replaced when discussing forced migrations.

  18. Correlations between Energy and Displacement Demands for Performance-Based Seismic Engineering

    Science.gov (United States)

    Mollaioli, Fabrizio; Bruno, Silvia; Decanini, Luis; Saragoni, Rodolfo

    2011-01-01

    (that can be considered as parameters representative of the amplitude, frequency content and duration of earthquake ground motions) and displacement-based response measures that are well correlated to structural and non-structural damage. For the purpose of quantifying the EDPs to be related to the energy measures, for comprehensive range of ground motion and structural characteristics, both simplified and more accurate numerical models will be used in this study for the estimation of local and global displacement and energy demands. Parametric linear and nonlinear time-history analyses will be performed on elastic and inelastic SDOF and MDOF systems, in order to assume information on the seismic response of a wide range of current structures. Hysteretic models typical of frame force/displacement behavior will be assumed for the local inelastic cyclic response of the systems. A wide range of vibration periods will be taken into account so as to define displacement, interstory drift and energy spectra for MDOF systems. Various scalar measures related to the deformation demand will be used in this research. These include the spectral displacements, the peak roof drift ratio, and the peak interstory drift ratio. A total of about 900 recorded ground motions covering a broad variety of condition in terms of frequency content, duration and amplitude will be used as input in the dynamic analyses. The records are obtained from 40 earthquakes and grouped as a function of magnitude of the event, source-to-site condition and site soil condition. In addition, in the data-set of records a considerable number of near-fault signals is included, in recognition of the particular significance of pulse-like time histories in causing large seismic demands to the structures.

  19. Annual report on contractor work force restructuring, fiscal year 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This report summarizes work force restructuring and community transition activities at all sites. It outlines work force restructuring activity for FY 1997, changing separation patterns, cost savings and separation costs, program assessment, activities to mitigate restructuring impacts, community transition activities, status of displaced workers, lessons learned, and emerging issues in worker and community transition. Work force restructuring and community transition activities for defense nuclear sites are summarized, as are work force restructuring activities at non-defense sites.

  20. Forced migration and indigenous knowledge of displaced Emberá and Uitoto populations in Colombia: An ethnobotanical perspective

    Directory of Open Access Journals (Sweden)

    Victor Hugo Gonzalez Betancourt

    2012-09-01

    Full Text Available Relatively little attention has been given to documenting changes in the ethnobotanical knowledge of displaced indigenous groups in Colombia. Such information is highly valuable because it contributes to our understanding of the changes that occur during this process of displacement, cultural transformation and loss, and because it eventually could shed some light in designing social, economic, and educational policies that would facilitate their incorporation into main stream culture, through ways that validate their indigenous identity, knowledge, and traditions. Based on our on-going research, herein we summarize ethnobotanical information of two indigenous groups currently residing in the city of Florencia (capital of the Department of Caquetá in the Northwestern Amazon basin: the Emberá, originally from northwestern Colombia, and Uitoto, originally from the Colombian Amazon. By focusing in the indigenous ethnobotanical knowledge of these two displaced groups, we intend to show the revitalization of ethnobotanical knowledge, resilience, and multiple resources in form of ancestral knowledge that are brought and transmitted by these groups as they struggle for survival, in many times hostile urban environments. We hope to draw more attention to and encourage similar studies on other displaced indigenous populations in Colombia as well as in other areas of Latin America. Normal 0 21 false false false ES-MX X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";}

  1. Internal Displacement: Livelihood saving responses

    OpenAIRE

    Deborah Hines

    2001-01-01

    Deborah Hines explores how to assist the internally displaced and those prone to displacement. She considers the major causes of internal displacement, making the case for a more comprehensive set of policy and operational actions in response to situations of internal displacement. Development (2001) 44, 34–39. doi:10.1057/palgrave.development.1110289

  2. Understanding the Experiences of Relocatees During Forced Relocation in Chinese Urban Restructuring

    NARCIS (Netherlands)

    Li, X.; van Ham, M.; Kleinhans, R.J.

    Despite the massive forced relocation of residents during urban restructuring in China, there are no systematic studies on how residents undergo the process. Most studies concerning urban restructuring in China directly equate forced relocation with displacement, which has a negative connotation.

  3. On the Influence of Piston and Cylinder Density in Tribodynamics of a Radial Piston Digital Fluid Power Displacement Motor

    DEFF Research Database (Denmark)

    Johansen, Per; Roemer, Daniel Beck; Andersen, Torben O.

    2015-01-01

    -stroke displacement simulations are used as basis for the parametric analysis. From the parametric analysis a change, in the minimum film thickness as function of piston and cylinder density, is shown for certain operating modes of the digital fluid power displacement motor. This indicate a need for careful....... In this paper the influence of the inertia term on the lubrication gaps of a radial piston motor are studied by a parametric analysis of the piston and cylinder density in a multibody tribodynamic simulation model. The motor is modeled as a digital fluid power displacement machine and a series of full...... assessment of the applicability, of the force balance condition, if it is used in multibody tribodynamic simulations of radial piston digital fluid power displacement motors....

  4. Dealing with the Effects of Sensor Displacement in Wearable Activity Recognition

    Directory of Open Access Journals (Sweden)

    Oresti Banos

    2014-06-01

    Full Text Available Most wearable activity recognition systems assume a predefined sensor deployment that remains unchanged during runtime. However, this assumption does not reflect real-life conditions. During the normal use of such systems, users may place the sensors in a position different from the predefined sensor placement. Also, sensors may move from their original location to a different one, due to a loose attachment. Activity recognition systems trained on activity patterns characteristic of a given sensor deployment may likely fail due to sensor displacements. In this work, we innovatively explore the effects of sensor displacement induced by both the intentional misplacement of sensors and self-placement by the user. The effects of sensor displacement are analyzed for standard activity recognition techniques, as well as for an alternate robust sensor fusion method proposed in a previous work. While classical recognition models show little tolerance to sensor displacement, the proposed method is proven to have notable capabilities to assimilate the changes introduced in the sensor position due to self-placement and provides considerable improvements for large misplacements.

  5. Examination of hydrodynamic force acting on a circular cylinder in vortex-induced vibrations in synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Linwei; Sun, Zhilin [Ocean College, Zhejiang University, Zhoushan, 316021 (China); Chan, Eng-Soon, E-mail: shenlinwei@zju.edu.cn [Department of Civil and Environmental Engineering, National University of Singapore, No. 1 Engineering Drive 2, Singapore 117576 (Singapore)

    2017-04-15

    An immersed boundary method is employed to simulate vortex-induced vibrations (VIV) of a circular cylinder in two dimensions. The Reynolds number is 150, and the cylinder mass ratios of 2 and 10 are considered. The synchronization regions for these two mass ratios are determined by the simulations. It is found that the cycle-averaged added mass is about zero at the reduced velocity of 6.1. The instantaneous frequency, which is obtained by Hilbert transformation of the cylinder oscillating displacement, exhibits an important feature whereby the cylinder oscillation in the VIV synchronization region is modulated with a frequency twice the displacement prevailing frequency. The cylinder displacement could still be well approximated by a sine function with a constant frequency and amplitude. However, the lift force acting on the cylinder cannot be estimated in the same manner. In fact, both the lift force amplitude and frequency are modulated. The suggested expression provides a better approximation of the lift force. Moreover, it reveals that the presence of the higher harmonics in the lift force is the result of the amplitude and frequency modulation. (paper)

  6. Public Health and Mental Health Implications of Environmentally Induced Forced Migration.

    Science.gov (United States)

    Shultz, James M; Rechkemmer, Andreas; Rai, Abha; McManus, Katherine T

    2018-03-28

    ABSTRACTClimate change is increasingly forcing population displacement, better described by the phrase environmentally induced forced migration. Rising global temperatures, rising sea levels, increasing frequency and severity of natural disasters, and progressive depletion of life-sustaining resources are among the drivers that stimulate population mobility. Projections forecast that current trends will rapidly accelerate. This will lead to an estimated 200 million climate migrants by the year 2050 and create dangerous tipping points for public health and security.Among the public health consequences of climate change, environmentally induced forced migration is one of the harshest and most harmful outcomes, always involving a multiplicity of profound resource and social losses and frequently exposing migrants to trauma and violence. Therefore, one particular aspect of forced migration, the effects of population displacement on mental health and psychosocial functioning, deserves dedicated focus. Multiple case examples are provided to elucidate this theme. (Disaster Med Public Health Preparedness. 2018;page 1 of 7).

  7. Ionizing/displacement synergistic effects induced by gamma and neutron irradiation in gate-controlled lateral PNP bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Chen, Wei; Yao, Zhibin; Jin, Xiaoming; Liu, Yan; Yang, Shanchao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Wang, Zhikuan [State Key Laboratory of Analog Integrated Circuit, Chongqing 400060 (China)

    2016-09-21

    A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to do experimental validations and studies on the ionizing/displacement synergistic effects in the lateral PNP bipolar transistor. The individual and mixed irradiation experiments of gamma rays and neutrons are accomplished on the transistors. The common emitter current gain, gate sweep characteristics and sub-threshold sweep characteristics are measured after each exposure. The results indicate that under the sequential irradiation of gamma rays and neutrons, the response of the gate-controlled lateral PNP bipolar transistor does exhibit ionizing/displacement synergistic effects and base current degradation is more severe than the simple artificial sum of those under the individual gamma and neutron irradiation. Enough attention should be paid to this phenomenon in radiation damage evaluation. - Highlights: • A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to facilitate the analysis of ionizing/displacement synergistic effects induced by the mixed irradiation of gamma and neutron. • The difference between ionizing/displacement synergistic effects and the simple sum of TID and displacement effects is analyzed. • The physical mechanisms of synergistic effects are explained.

  8. Simulation and analysis of vertical displacement characteristics of three wheels reverse trike vehicle with PID controller application

    Science.gov (United States)

    Wibowo, Lambang, Lullus; Erick Chandra, N.; Muhayat, Nurul; Jaka S., B.

    2017-08-01

    The purpose of this research is to obtain a mathematical model (Full Vehicle Model) and compare the performance of passive and active suspension systems of a Three-Wheels Reverse Trike vehicle. Vehicle suspension system should able to provide good steering handling and passenger comfort. Vehicle suspension system generally only uses passive suspension components with fix spring and damper coefficients. An active suspension developed from the traditional (passive) suspension design can directly control the actuator force in the suspension system. In this paper, modeling and simulation of passive and active suspension system for a Full Vehicle Model is performed using Simulink-MATLAB software. Ziegler & Nichols tuning method is used to obtain controller parameters of Proportional Integral Derivative (PID) controller. Comparison between passive and active suspension with PID controller is conducted for disturbances input of single bump road surface profile 0.1 meters. The results are the displacement and acceleration of the vehicle body in the vertical direction of active suspension system with PID control is better in providing handling capabilities and comfort for the driver than of passive suspension system. The acceleration of 1,8G with the down time of 2.5 seconds is smaller than the acceleration of 2.5G with down time of 5.5 seconds.

  9. Sit-to-stand ground reaction force characteristics in blind and sighted female children.

    Science.gov (United States)

    Faraji Aylar, Mozhgan; Jafarnezhadgero, Amir Ali; Salari Esker, Fatemeh

    2018-03-05

    The association between visual sensory and sit-to-stand ground reaction force characteristics is not clear. Impulse is the amount of force applied over a period of time. Also, free moment represents the vertical moment applied in the center of pressure (COP). How the ground reaction force components, vertical loading rate, impulses and free moment respond to long and short term restricted visual information? Fifteen female children with congenital blindness and 45 healthy girls with no visual impairments participated in this study. The girls with congenital blindness were placed in one group and the 45 girls with no visual impairments were randomly divided into three groups of 15; eyes open, permanently eyes closed, and temporary eyes closed. The participants in the permanently eyes closed group closed their eyes for 20 min before the test, whereas temporary eyes closed group did tests with their eyes closed throughout, and those in the eyes open group kept their eyes open. Congenital blindness was associated with increased vertical loading rate, range of motion of knee and hip in the medio-lateral plane. Also, medio-lateral and vertical ground reaction force impulses. Similar peak negative and positive free moments were observed in three groups. In conclusion, the results reveal that sit-to-stand ground reaction force components in blind children may have clinical importance for improvement of balance control of these individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. The effects of femoral neck cut, cable tension, and muscles forces on the greater trochanter fixation.

    Science.gov (United States)

    Petit, Yvan; Cloutier, Luc P; Duke, Kajsa; Laflamme, G Yves

    2012-04-01

    Greater trochanter (GT) stabilization techniques following a fracture or an osteotomy are still showing high levels of postoperative complications. Understanding the effect of femoral neck cut placement, cable tension and muscles forces on GT fragment displacements could help surgeons optimize their techniques. A 3D finite element model has been developed to evaluate, through a statistical experimental design, the impact of the above variables on the GT fragment gap and sliding displacements. Muscles forces were simulating typical daily activities. Stresses were also investigated. The femoral neck cut placement had the most significant effect on the fragment displacement. Lowering it by 5 mm increased the gap and sliding fragment displacements by 288 and 128 %, respectively. Excessive cable tightening provided no significant reduction in fragment displacement. Muscle activities increased the gap and the sliding displacements for all muscle configurations. The maximum total displacement of 0.41 mm was present with a 10 mm femoral neck cut, a cable tension of 178 N, and stair climbing. Caution must be used not to over tighten the cables as the potential damage caused by the increased stress is more significant than any reduction in fragment displacement. Furthermore, preservation of the contact area is important for GT stabilization.

  11. Numerical procedure for fluid-structure interaction with structure displacements limited by a rigid obstacle

    Directory of Open Access Journals (Sweden)

    Yakhlef O.

    2017-06-01

    Full Text Available A fixed point algorithmis proposed to solve a fluid-structure interaction problem with the supplementary constraint that the structure displacements are limited by a rigid obstacle. Fictitious domain approach with penalization is used for the fluid equations. The surface forces from the fluid acting on the structure are computed using the fluid solution in the structure domain. The continuity of the fluid and structure velocities is imposed through the penalization parameter. The constraint of non-penetration of the elastic structure into the rigid obstacle is treated weakly. A convex constrained optimization problem is solved in order to get the structure displacements. Numerical results are presented.

  12. Quantum mechanical methods for calculation of force constants

    International Nuclear Information System (INIS)

    Mullally, D.J.

    1985-01-01

    The focus of this thesis is upon the calculation of force constants; i.e., the second derivatives of the potential energy with respect to nuclear displacements. This information is useful for the calculation of molecular vibrational modes and frequencies. In addition, it may be used for the location and characterization of equilibrium and transition state geometries. The methods presented may also be applied to the calculation of electric polarizabilities and infrared and Raman vibrational intensities. Two approaches to this problem are studied and evaluated: finite difference methods and analytical techniques. The most suitable method depends on the type and level of theory used to calculate the electronic wave function. Double point displacement finite differencing is often required for accurate calculation of the force constant matrix. These calculations require energy and gradient calculations on both sides of the geometry of interest. In order to speed up these calculations, a novel method is presented that uses geometry dependent information about the wavefunction. A detailed derivation for the analytical evaluation of force constants with a complete active space multiconfiguration self consistent field wave function is presented

  13. The Displacement of the Possible: Popular Experience and Gentrification at Historic Center of Mexico City

    Directory of Open Access Journals (Sweden)

    Vicente Moctezuma Mendoza

    2016-09-01

    Full Text Available This paper studies the displacement of popular sectors in the Historic Center of Mexico City as part of the gentrification process in this space. Particularly, it analyzes a form of displacement that the author defines as ‘the displacement in popular horizons of the possible’, and supposes a reinterpretation – from the characteristics of the gentrification processes in Latin America and the anthropologic fieldwork- of the definition of ‘exclusionary displacement’ proposed by Peter Marcuse. Displacement is analyzed through an ethnographic approach to some residential itineraries that account for popular sectors different rooting constructions during the second half of the twentieth century and the review of the permanence or disappearance of such conditions in the contemporary context.

  14. In Vivo MRI Measurement of Spinal Cord Displacement in the Thoracolumbar Region of Asymptomatic Subjects with Unilateral and Sham Straight Leg Raise Tests.

    Directory of Open Access Journals (Sweden)

    M Rade

    Full Text Available Normal displacement of the conus medullaris with unilateral and bilateral SLR has been quantified and the "principle of linear dependence" has been described.Explore whether previously recorded movements of conus medullaris with SLRs are i primarily due to transmission of tensile forces transmitted through the neural tissues during SLR or ii the result of reciprocal movements between vertebrae and nerves.Controlled radiologic study.Ten asymptomatic volunteers were scanned with a 1.5T magnetic resonance (MR scanner using T2 weighted spc 3D scanning sequences and a device that permits greater ranges of SLR. Displacement of the conus medullaris during the unilateral and sham SLR was quantified reliably with a randomized procedure. Conus displacement in response to unilateral and sham SLRs was quantified and the results compared.The conus displaced caudally in the spinal canal by 3.54±0.87 mm (mean±SD with unilateral (p≤.001 and proximally by 0.32±1.6 mm with sham SLR (p≤.542. Pearson correlations were higher than 0.99 for both intra- and inter-observer reliability and the observed power was 1 for unilateral SLRs and 0.054 and 0.149 for left and right sham SLR respectively.Four relevant points emerge from the presented data: i reciprocal movements between the spinal cord and the surrounding vertebrae are likely to occur during SLR in asymptomatic subjects, ii conus medullaris displacement in the vertebral canal with SLR is primarily due to transmission of tensile forces through the neural tissues, iii when tensile forces are transmitted through the neural system as in the clinical SLR, the magnitude of conus medullaris displacement prevails over the amount of bone adjustment.

  15. Simulation Analysis and Experiment of Variable-Displacement Asymmetric Axial Piston Pump

    Directory of Open Access Journals (Sweden)

    Youshan Gao

    2017-03-01

    Full Text Available The variable displacement pump control system has greater energy-saving advantages and application prospects than the valve control system. However, the variable displacement pump control of differential cylinder is not concurrent with the existing technologies. The asymmetric pump-controlled cylinder is, therefore, used to balance the unequal volume flow through a single rod cylinder in closed-circuit system. This is considered to be an effective method. Nevertheless, the asymmetric axial piston pump (AAPP is a constant displacement pump. In this study, variable-displacement asymmetric axial piston pump (VAPP is investigated according to the same principle used in investigating AAPP. This study, therefore, aims at investigating the characteristics of VAPP. The variable-displacement output of VAPP is implemented by controlling the swash plate angle with angle feedback control circuit, which is composed of a servo proportional valve and an angular displacement sensor. The angular displacement sensor is connected to the swash plate. The simulation model of VAPP, which is set up through the ITI-SimulationX simulation platform, is used to predict VAPP’s characteristics. The purpose of implementing the experiment is to verify the theoretical results. Both the simulation and the experiment results demonstrated that the swash plate angle is controlled by a variable mechanism; when the swash plate angle increases, the flow of Port B and Port T increases while the response speed of Port B and Port T also accelerates. When the swash plate angle is constant, the flow of Port B and Port T increases along with the increase of pump speed, although the pressure-response speed of Port B is faster than that of Port T. Consequently, the flow pulsation of Port B and Port T tends to decrease gradually along with the increase of pump speed. When the pressure loaded on Port B equals to that of Port T, the flow ripple cycle of Port B is longer than that of Port T

  16. Detecting the position of the moving-iron solenoid by non-displacement sensor based on parameter identification of flux linkage characteristics

    Science.gov (United States)

    Wang, Xuping; Quan, Long; Xiong, Guangyu

    2013-11-01

    Currently, most researches use signals, such as the coil current or voltage of solenoid, to identify parameters; typically, parameter identification method based on variation rate of coil current is applied for position estimation. The problem exists in these researches that the detected signals are prone to interference and difficult to obtain. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which adds a new group of secondary winding to the coil of the ordinary switching electromagnet. On the basis of electromagnetic coupling theory analysis and simulation research of the magnetic field regarding the primary and secondary winding coils, and in accordance with the fact that under PWM control mode varying core position and operating current of windings produce different characteristic of flux increment of the secondary winding. The flux increment of the electromagnet winding can be obtained by conducting time domain integration for the induced voltage signal of the extracted secondary winding, and the core position from the two-dimensional fitting curve of the operating winding current and flux-linkage characteristic quantity of solenoid are calculated. The detecting and testing system of solenoid core position is developed based on the theoretical research. The testing results show that the flux characteristic quantity of switching electromagnet magnetic circuit is able to effectively show the core position and thus to accomplish the non-displacement transducer detection of the said core position of the switching electromagnet. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which provides a new theory and method for switch solenoid to control the proportional valve.

  17. Improved SAR Amplitude Image Offset Measurements for Deriving Three-Dimensional Coseismic Displacements

    KAUST Repository

    Wang, Teng; Jonsson, Sigurjon

    2015-01-01

    Offsets of synthetic aperture radar (SAR) images have played an important role in deriving complete three-dimensional (3-D) surface displacement fields in geoscientific applications. However, offset maps often suffer from multiple outliers and patch-like artifacts, because the standard offset-measurement method is a regular moving-window operation that does not consider the scattering characteristics of the ground. Here, we show that by focusing the offset measurements on predetected strong reflectors, the reliability and accuracy of SAR offsets can be significantly improved. Application to the 2011 Van (Turkey) earthquake reveals a clear deformation signal from an otherwise decorrelated interferogram, making derivation of the 3-D coseismic displacement field possible. Our proposed method can improve mapping of coseismic deformation and other ground displacements, such as glacier flow and landslide movement when strong reflectors exist.

  18. Improved SAR Amplitude Image Offset Measurements for Deriving Three-Dimensional Coseismic Displacements

    KAUST Repository

    Wang, Teng

    2015-02-03

    Offsets of synthetic aperture radar (SAR) images have played an important role in deriving complete three-dimensional (3-D) surface displacement fields in geoscientific applications. However, offset maps often suffer from multiple outliers and patch-like artifacts, because the standard offset-measurement method is a regular moving-window operation that does not consider the scattering characteristics of the ground. Here, we show that by focusing the offset measurements on predetected strong reflectors, the reliability and accuracy of SAR offsets can be significantly improved. Application to the 2011 Van (Turkey) earthquake reveals a clear deformation signal from an otherwise decorrelated interferogram, making derivation of the 3-D coseismic displacement field possible. Our proposed method can improve mapping of coseismic deformation and other ground displacements, such as glacier flow and landslide movement when strong reflectors exist.

  19. Inductive Displacement Sensors with a Notch Filter for an Active Magnetic Bearing System

    Directory of Open Access Journals (Sweden)

    Seng-Chi Chen

    2014-07-01

    Full Text Available Active magnetic bearing (AMB systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and axial movement of the suspended object. In a high-speed rotating machine equipped with an AMB, the rotor bending modes may be limited to the operating range. The natural frequencies of the rotor can cause instability. Thus, notch filters are a useful circuit for stabilizing the system. In addition, commercial displacement sensors are sometimes not suitable for AMB design, and cannot filter the noise caused by the natural frequencies of rotor. Hence, implementing displacement sensors based on the AMB structure is necessary to eliminate noises caused by natural frequency disturbances. The displacement sensor must be highly sensitive in the desired working range, and also exhibit a low interference noise, high stability, and low cost. In this study, we used the differential inductive sensor head and lock-in amplifier for synchronous demodulation. In addition, an active low-pass filter and a notch filter were used to eliminate disturbances, which caused by natural frequencies. As a consequence, the inductive displacement sensor achieved satisfactory linearity, high sensitivity, and disturbance elimination. This sensor can be easily produced for AMB applications. A prototype of these displacement sensors was built and tested.

  20. A Combined Approach to Cartographic Displacement for Buildings Based on Skeleton and Improved Elastic Beam Algorithm

    Science.gov (United States)

    Liu, Yuangang; Guo, Qingsheng; Sun, Yageng; Ma, Xiaoya

    2014-01-01

    Scale reduction from source to target maps inevitably leads to conflicts of map symbols in cartography and geographic information systems (GIS). Displacement is one of the most important map generalization operators and it can be used to resolve the problems that arise from conflict among two or more map objects. In this paper, we propose a combined approach based on constraint Delaunay triangulation (CDT) skeleton and improved elastic beam algorithm for automated building displacement. In this approach, map data sets are first partitioned. Then the displacement operation is conducted in each partition as a cyclic and iterative process of conflict detection and resolution. In the iteration, the skeleton of the gap spaces is extracted using CDT. It then serves as an enhanced data model to detect conflicts and construct the proximity graph. Then, the proximity graph is adjusted using local grouping information. Under the action of forces derived from the detected conflicts, the proximity graph is deformed using the improved elastic beam algorithm. In this way, buildings are displaced to find an optimal compromise between related cartographic constraints. To validate this approach, two topographic map data sets (i.e., urban and suburban areas) were tested. The results were reasonable with respect to each constraint when the density of the map was not extremely high. In summary, the improvements include (1) an automated parameter-setting method for elastic beams, (2) explicit enforcement regarding the positional accuracy constraint, added by introducing drag forces, (3) preservation of local building groups through displacement over an adjusted proximity graph, and (4) an iterative strategy that is more likely to resolve the proximity conflicts than the one used in the existing elastic beam algorithm. PMID:25470727

  1. Evaluation of Stiffness Changes in a High-Rise Building by Measurements of Lateral Displacements Using GPS Technology

    Science.gov (United States)

    Choi, Se Woon; Kim, Ill Soo; Park, Jae Hwan; Kim, Yousok; Sohn, Hong Gyoo; Park, Hyo Seon

    2013-01-01

    The outrigger truss system is one of the most frequently used lateral load resisting structural systems. However, little research has been reported on the effect of installation of outrigger trusses on improvement of lateral stiffness of a high-rise building through full-scale measurements. In this paper, stiffness changes of a high-rise building due to installation of outrigger trusses have been evaluated by measuring lateral displacements using a global positioning system (GPS). To confirm the error range of the GPS measurement system used in the full-scale measurement tests, the GPS displacement monitoring system is investigated through a free vibration test of the experimental model. Then, for the evaluation of lateral stiffness of a high-rise building under construction, the GPS displacement monitoring system is applied to measurements of lateral displacements of a 66-story high-rise building before and after installation of outrigger truss. The stiffness improvement of the building before and after the installation is confirmed through the changes of the natural frequencies and the ratios of the base shear forces to the roof displacements. PMID:24233025

  2. Evaluation of Stiffness Changes in a High-Rise Building by Measurements of Lateral Displacements Using GPS Technology

    Directory of Open Access Journals (Sweden)

    Se Woon Choi

    2013-11-01

    Full Text Available The outrigger truss system is one of the most frequently used lateral load resisting structural systems. However, little research has been reported on the effect of installation of outrigger trusses on improvement of lateral stiffness of a high-rise building through full-scale measurements. In this paper, stiffness changes of a high-rise building due to installation of outrigger trusses have been evaluated by measuring lateral displacements using a global positioning system (GPS. To confirm the error range of the GPS measurement system used in the full-scale measurement tests, the GPS displacement monitoring system is investigated through a free vibration test of the experimental model. Then, for the evaluation of lateral stiffness of a high-rise building under construction, the GPS displacement monitoring system is applied to measurements of lateral displacements of a 66-story high-rise building before and after installation of outrigger truss. The stiffness improvement of the building before and after the installation is confirmed through the changes of the natural frequencies and the ratios of the base shear forces to the roof displacements.

  3. Limitations of radiographs in evaluating non-displaced osteochondral lesions of the talus

    International Nuclear Information System (INIS)

    Dheer, Sachin; Khan, Mustafa; Zoga, Adam C.; Morrison, William B.

    2012-01-01

    To evaluate what limitations, if any, radiographs have in detecting and characterizing the morphology of non-displaced OCLTs (size, cystic change, fragmentation, and avascular necrosis [AVN]). Thirty-three OCLTs in 32 patients were reviewed in consensus by a board-certified, fellowship-trained musculoskeletal radiologist and orthopedic surgeon, on radiographs and MRI examinations performed within 15 days of one another. Location, dimensions, and characteristics of the OCLT (fragmentation, bone marrow edema, cystic change, and necrosis) were documented on the radiographs and MRI examinations. There was an average of 7.5 days (range: 1-15 days) between the MRIs and radiographs. Eighteen (55%) medial and 15 (45%) lateral OCLTs were found; none was displaced. OCLTs were categorized into three groups: Group 1 - initially diagnosed with radiographs (4/33; 12%), Group 2 - diagnosed with radiographs only after MRI correlation (20/33; 61%), and Group 3 - not identifiable on radiographs despite MRI correlation (9/33; 27%). The dimensions of all of the lesions in Groups 1 and 2 were underestimated on radiographs. Only 1 of the 4 (25%) lesions in Group 1 and 1 of the 20 (5%) lesions in Group 2 could be measured in the anteroposterior (AP) dimension (using a lateral radiograph). The most common radiographic appearance of non-displaced OCLTs was an ''ill-defined'' lucency at the talar dome (20/33; 61%). Across all three groups, fragmentation, cystic change, and AVN were radiographically apparent in 3/10 (30%), 4/19 (21%), and 1/6 (17%) cases respectively. Compared with MRI, radiographs are limited in their evaluation of the size (particularly the AP dimension) and characteristics (fragmentation, cystic change, and AVN) of non-displaced OCLTs. The most common appearance of non-displaced OCLTs is an ''ill-defined'' lucency at the talar dome. When this appearance is also considered, the estimated retrospective sensitivity of radiographs improves considerably. (orig.)

  4. Contribution of Leg-Muscle Forces to Paddle Force and Kayak Speed During Maximal-Effort Flat-Water Paddling.

    Science.gov (United States)

    Nilsson, Johnny E; Rosdahl, Hans G

    2016-01-01

    The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted--the knee joints "locked." Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers' paddling performance.

  5. A nondestructive, reproducible method of measuring joint reaction force at the distal radioulnar joint.

    Science.gov (United States)

    Canham, Colin D; Schreck, Michael J; Maqsoodi, Noorullah; Doolittle, Madison; Olles, Mark; Elfar, John C

    2015-06-01

    To develop a nondestructive method of measuring distal radioulnar joint (DRUJ) joint reaction force (JRF) that preserves all periarticular soft tissues and more accurately reflects in vivo conditions. Eight fresh-frozen human cadaveric limbs were obtained. A threaded Steinmann pin was placed in the middle of the lateral side of the distal radius transverse to the DRUJ. A second pin was placed into the middle of the medial side of the distal ulna colinear to the distal radial pin. Specimens were mounted onto a tensile testing machine using a custom fixture. A uniaxial distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Force-displacement curves were generated and a best-fit polynomial was solved to determine JRF. All force-displacement curves demonstrated an initial high slope where relatively large forces were required to distract the joint. This ended with an inflection point followed by a linear area with a low slope, where small increases in force generated larger amounts of distraction. Each sample was measured 3 times and there was high reproducibility between repeated measurements. The average baseline DRUJ JRF was 7.5 N (n = 8). This study describes a reproducible method of measuring DRUJ reaction forces that preserves all periarticular stabilizing structures. This technique of JRF measurement may also be suited for applications in the small joints of the wrist and hand. Changes in JRF can alter native joint mechanics and lead to pathology. Reliable methods of measuring these forces are important for determining how pathology and surgical interventions affect joint biomechanics. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  6. Vertical Finger Displacement Is Reduced in Index Finger Tapping During Repeated Bout Rate Enhancement.

    Science.gov (United States)

    Mora-Jensen, Mark Holten; Madeleine, Pascal; Hansen, Ernst Albin

    2017-10-01

    The present study analyzed (a) whether a recently reported phenomenon of repeated bout rate enhancement in finger tapping (i.e., a cumulating increase in freely chosen finger tapping frequency following submaximal muscle activation in the form of externally unloaded voluntary tapping) could be replicated and (b) the hypotheses that the faster tapping was accompanied by changed vertical displacement of the fingertip and changed peak force during tapping. Right-handed, healthy, and recreationally active individuals (n = 24) performed two 3-min index finger tapping bouts at freely chosen tapping frequency, separated by 10-min rest. The recently reported phenomenon of repeated bout rate enhancement was replicated. The faster tapping (8.8 ± 18.7 taps/min, corresponding to 6.0 ± 11.0%, p = .033) was accompanied by reduced vertical displacement (1.6 ± 2.9 mm, corresponding to 6.3 ± 14.9%, p = .012) of the fingertip. Concurrently, peak force was unchanged. The present study points at separate control mechanisms governing kinematics and kinetics during finger tapping.

  7. Model tests and numerical analysis on restoring force characteristics of reactor buildings

    International Nuclear Information System (INIS)

    Uchiyama, Y.; Suzuki, S.; Akino, K.

    1987-01-01

    Seismic shear walls of nuclear reactor buildings are composed of cylindrical, truncated cone-shape, box-shape, irregular polygonal walls or its combination and they are generally heavily reinforced concrete (RC) walls. So the elasto-plastic behaviors of those RC structures in ultimate regions have many unsolved and may be considered as especially important factors for explaining nonlinear response of nuclear reactor buildings. Following these research demands, the authors have prepared a nonlinear F.E.M. code called ''SANREF'' and made an extensive study for the restoring force characteristics of the inner concrete structures (I/C) of a PWR-type containment vessel and the principal seismic shear walls of a BWR-type reactor building by some series of reduced model tests and simulation analysis for the tests results. The detailed objectives of this study can be summarized as follows: (1) Examine the effectiveness of the configurations of shear walls, reinforcement ratios, shear span ratios (M/Qd) and vertical axial stress by ''partial model test'' which simulates some independent shear walls of the PWR-type and BWR-type reactor buildings. (2) Obtain fundamental data of restoring force characteristics of the complex shaped RC structures by ''composite model test'' which models are composed of the partial model test specimens. (3) Verify the applicability of analytical methods and constitutive modelings in SANREF code for complex shaped RC structures through nonlinear simulation analysis for the composite model test

  8. Vision Based Displacement Detection for Stabilized UAV Control on Cloud Server

    Directory of Open Access Journals (Sweden)

    Hyeok-June Jeong

    2016-01-01

    Full Text Available Nowadays, image processing solution is used in many fields such as traffic information systems and illegal intrusion detection systems. Now, to assist with the control of camera-equipped devices, appropriate image processing techniques are needed for moving rather than fixed observers. For achieving this goal, an algorithm should derive the desired results quickly and accurately; thus, this paper considers two characteristics: functional performance (reliability and temporal performance (efficiency. Reliability means how well the desired results can be achieved, and efficiency means how quickly the result can be calculated. This paper suggests an optimized real-time image algorithm based on the integration of the optical flow and Speeded-Up Robust Features (SURF algorithms. This algorithm determines horizontal or vertical movement of the camera and then extracts its displacement. The proposed algorithm can be used to stabilize an Unmanned Aerial Vehicle (UAV in situations where it is drifting due to inertia and external forces, like wind, in parallel. The proposed algorithm is efficient in achieving drift stabilization by movement detection; however, it is not appropriate for image processing in small UAVs. To solve this problem, this study proposes an image processing method that uses a high-performance computer.

  9. Comparing the impact of time displaced and biased precipitation estimates for online updated urban runoff models.

    Science.gov (United States)

    Borup, Morten; Grum, Morten; Mikkelsen, Peter Steen

    2013-01-01

    When an online runoff model is updated from system measurements, the requirements of the precipitation input change. Using rain gauge data as precipitation input there will be a displacement between the time when the rain hits the gauge and the time where the rain hits the actual catchment, due to the time it takes for the rain cell to travel from the rain gauge to the catchment. Since this time displacement is not present for system measurements the data assimilation scheme might already have updated the model to include the impact from the particular rain cell when the rain data is forced upon the model, which therefore will end up including the same rain twice in the model run. This paper compares forecast accuracy of updated models when using time displaced rain input to that of rain input with constant biases. This is done using a simple time-area model and historic rain series that are either displaced in time or affected with a bias. The results show that for a 10 minute forecast, time displacements of 5 and 10 minutes compare to biases of 60 and 100%, respectively, independent of the catchments time of concentration.

  10. Short-range fundamental forces

    International Nuclear Information System (INIS)

    Antoniadis, I.; Baessler, S.; Buchner, M.; Fedorov, V.V.; Hoedl, S.; Nesvizhevsky, V.V.; Pignol, G.; Protasov, K.V.; Lambrecht, A.; Reynaud, S.; Sobolev, Y.

    2010-01-01

    We consider theoretical motivations to search for extra short-range fundamental forces as well as experiments constraining their parameters. The forces could be of two types: 1) spin-independent forces; 2) spin-dependent axion-like forces. Different experimental techniques are sensitive in respective ranges of characteristic distances. The techniques include measurements of gravity at short distances, searches for extra interactions on top of the Casimir force, precision atomic and neutron experiments. We focus on neutron constraints, thus the range of characteristic distances considered here corresponds to the range accessible for neutron experiments

  11. On Displacement Height, from Classical to Practical Formulation: Stress, Turbulent Transport and Vorticity Considerations

    Science.gov (United States)

    Sogachev, Andrey; Kelly, Mark

    2016-03-01

    Displacement height ( d) is an important parameter in the simple modelling of wind speed and vertical fluxes above vegetative canopies, such as forests. Here we show that, aside from implicit definition through a (displaced) logarithmic profile, accepted formulations for d do not consistently predict flow properties above a forest. Turbulent transport can affect the displacement height, and is an integral part of what is called the roughness sublayer. We develop a more general approach for estimation of d, through production of turbulent kinetic energy and turbulent transport, and show how previous stress-based formulations for displacement height can be seen as simplified cases of a more general definition including turbulent transport. Further, we also give a simplified and practical form for d that is in agreement with the general approach, exploiting the concept of vortex thickness scale from mixing-layer theory. We assess the new and previous displacement height formulations by using flow statistics derived from the atmospheric boundary-layer Reynolds-averaged Navier-Stokes model SCADIS as well as from wind-tunnel observations, for different vegetation types and flow regimes in neutral conditions. The new formulations tend to produce smaller d than stress-based forms, falling closer to the classic logarithmically-defined displacement height. The new, more generally defined, displacement height appears to be more compatible with profiles of components of the turbulent kinetic energy budget, accounting for the combined effects of turbulent transport and shear production. The Coriolis force also plays a role, introducing wind-speed dependence into the behaviour of the roughness sublayer; this affects the turbulent transport, shear production, stress, and wind speed, as well as the displacement height, depending on the character of the forest. We further show how our practical (`mixing-layer') form for d matches the new turbulence-based relation, as well as

  12. Designing an experiment to measure cellular interaction forces

    Science.gov (United States)

    McAlinden, Niall; Glass, David G.; Millington, Owain R.; Wright, Amanda J.

    2013-09-01

    Optical trapping is a powerful tool in Life Science research and is becoming common place in many microscopy laboratories and facilities. The force applied by the laser beam on the trapped object can be accurately determined allowing any external forces acting on the trapped object to be deduced. We aim to design a series of experiments that use an optical trap to measure and quantify the interaction force between immune cells. In order to cause minimum perturbation to the sample we plan to directly trap T cells and remove the need to introduce exogenous beads to the sample. This poses a series of challenges and raises questions that need to be answered in order to design a set of effect end-point experiments. A typical cell is large compared to the beads normally trapped and highly non-uniform - can we reliably trap such objects and prevent them from rolling and re-orientating? In this paper we show how a spatial light modulator can produce a triple-spot trap, as opposed to a single-spot trap, giving complete control over the object's orientation and preventing it from rolling due, for example, to Brownian motion. To use an optical trap as a force transducer to measure an external force you must first have a reliably calibrated system. The optical trapping force is typically measured using either the theory of equipartition and observing the Brownian motion of the trapped object or using an escape force method, e.g. the viscous drag force method. In this paper we examine the relationship between force and displacement, as well as measuring the maximum displacement from equilibrium position before an object falls out of the trap, hence determining the conditions under which the different calibration methods should be applied.

  13. Non-Colocated Kinesthetic Display Limits Compliance Discrimination in the Absence of Terminal Force Cues.

    Science.gov (United States)

    Brown, Jeremy D; Shelley, Mackenzie K; Gardner, Duane; Gansallo, Emmanuel A; Gillespie, R Brent

    2016-01-01

    An important goal of haptic display is to make available the action/reaction relationships that define interactions between the body and the physical world. While in physical world interactions reaction cues invariably impinge on the same part of the body involved in action (reaction and action are colocated), a haptic interface is quite capable of rendering feedback to a separate body part than that used for producing exploratory actions (non-colocated action and reaction). This most commonly occurs with the use of vibrotactile display, in which a cutaneous cue has been substituted for a kinesthetic cue (a kind of sensory substitution). In this paper, we investigate whether non-colocated force and displacement cues degrade the perception of compliance. Using a custom non-colocated kinesthetic display in which one hand controls displacement and the other senses force, we ask participants to discriminate between two virtual springs with matched terminal force and adjustable non-linearity. An additional condition includes one hand controlling displacement while the other senses force encoded in a vibrotactile cue. Results show that when the terminal force cue is unavailable, and even when sensory substitution is not involved, non-colocated kinesthetic displays degrade compliance discrimination relative to colocated kinesthetic displays. Compliance discrimination is also degraded with vibrotactile display of force. These findings suggest that non-colocated kinesthetic displays and, likewise, cutaneous sensory substitution displays should be avoided when discrimination of compliance is necessary for task success.

  14. Effects of magnetic history on the levitation characteristics in a superconducting levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xingyi [Key Laboratory of Mechanics on Western Disaster and Environment and Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Zhou Youhe [Key Laboratory of Mechanics on Western Disaster and Environment and Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)], E-mail: zhouyh@lzu.edu.cn; Zhou Jun [Key Laboratory of Mechanics on Western Disaster and Environment and Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2008-07-15

    Using an updated high-temperature superconductor maglev measurement system, influences of the motion mode in which both the superconductor and the magnet are placed close to each other on the magnetic forces and their relaxation are measured. It is found that Method 1, in which the magnet coaxially approaches the superconductor which is subsequently displaced laterally, leads to reduce the relaxation both in the levitation force and in the lateral force in comparison to Method 2, where lateral displacement of superconductor occurs before vertical motion of the magnet. The results are relevant for the practical levitation systems.

  15. Linear-hall sensor based force detecting unit for lower limb exoskeleton

    Science.gov (United States)

    Li, Hongwu; Zhu, Yanhe; Zhao, Jie; Wang, Tianshuo; Zhang, Zongwei

    2018-04-01

    This paper describes a knee-joint human-machine interaction force sensor for lower-limb force-assistance exoskeleton. The structure is designed based on hall sensor and series elastic actuator (SEA) structure. The work we have done includes the structure design, the parameter determination and dynamic simulation. By converting the force signal into macro displacement and output voltage, we completed the measurement of man-machine interaction force. And it is proved by experiments that the design is simple, stable and low-cost.

  16. Quantitative Study of Nanoscale Contact and Pre-Contact Mechanics Using Force Modulation

    National Research Council Canada - National Science Library

    Syed Asif, S. A; Wahl, K. J; Colton, R. J

    1999-01-01

    .... However cantilever instability, conventional force detection and displacement sensing make contact area measurement difficult, hence the measured mechanical properties are usually only qualitative...

  17. The mechanics of buccal canine retraction springs for removable orthodontic appliances.

    Science.gov (United States)

    Waters, N E

    1982-07-01

    The force-displacement characteristics of three types of buccal-canine retraction spring to both horizontal (normal) and vertical displacements is derived from simple beam theory. The analyses are used to examine theoretically the effect of variations in the geometry of a given type of spring and also to compare the merits of three designs in terms of the force applied on activation, and their stability to vertical displacement. Experimental measurements on enlarged models of the force-displacement behaviour were in good agreement with the values predicted by the derived equations.

  18. The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks.

    Science.gov (United States)

    Müller, Corsin A; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

    2014-08-01

    Visible and invisible displacement tasks have been used widely for comparative studies of animals' understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and, thus, reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so because of their inability to form a mental representation of the target object, or simply because of the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object's location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species' performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past.

  19. In Situ Observation of Hard Surrounding Rock Displacement at 2400-m-Deep Tunnels

    Science.gov (United States)

    Feng, Xia-Ting; Yao, Zhi-Bin; Li, Shao-Jun; Wu, Shi-Yong; Yang, Cheng-Xiang; Guo, Hao-Sen; Zhong, Shan

    2018-03-01

    This paper presents the results of in situ investigation of the internal displacement of hard surrounding rock masses within deep tunnels at China's Jinping Underground Laboratory Phase II. The displacement evolution of the surrounding rock during the entire excavation processes was monitored continuously using pre-installed continuous-recording multi-point extensometers. The evolution of excavation-damaged zones and fractures in rock masses were also observed using acoustic velocity testing and digital borehole cameras, respectively. The results show four kinds of displacement behaviours of the hard surrounding rock masses during the excavation process. The displacement in the inner region of the surrounding rock was found to be greater than that of the rock masses near the tunnel's side walls in some excavation stages. This leads to a multi-modal distribution characteristic of internal displacement for hard surrounding rock masses within deep tunnels. A further analysis of the evolution information on the damages and fractures inside the surrounding rock masses reveals the effects of excavation disturbances and local geological conditions. This recognition can be used as the reference for excavation and supporting design and stability evaluations of hard-rock tunnels under high-stress conditions.

  20. 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.

  1. Calculation of static characteristics of linear step motors for control rod drives of nuclear reactors - an approximate approach

    International Nuclear Information System (INIS)

    Khan, S.H.; Ivanov, A.A.

    1993-01-01

    This paper describes an approximate method for calculating the static characteristics of linear step motors (LSM), being developed for control rod drives (CRD) in large nuclear reactors. The static characteristic of such an LSM which is given by the variation of electromagnetic force with armature displacement determines the motor performance in its standing and dynamic modes. The approximate method of calculation of these characteristics is based on the permeance analysis method applied to the phase magnetic circuit of LSM. This is a simple, fast and efficient analytical approach which gives satisfactory results for small stator currents and weak iron saturation, typical to the standing mode of operation of LSM. The method is validated by comparing theoretical results with experimental ones. (Author)

  2. Unaccompanied Asylum-Seeking Refugee Children’s Forced Repatriation: Social Workers’ and Police Officers’ Health and Job Characteristics

    Science.gov (United States)

    Sundqvist, Johanna; Hansson, Jonas; Ghazinour, Mehdi; Ögren, Kenneth; Padyab, Mojgan

    2015-01-01

    During the past ten years the number of unaccompanied asylum-seeking refugee children has dramatically increased in Sweden. Some of them are permitted to stay in the receiving country, but some are forced back to their country of origin. Social workers and police officers are involved in these forced repatriations, and such complex situations may cause stressful working conditions. This study aimed to bridge the gap in knowledge of the relationship between general mental health and working with unaccompanied asylum-seeking refugee children who are due for forced repatriation. In addition, the role of psychosocial job characteristics in such relationships was investigated. A questionnaire including sociodemographic characteristics, the Swedish Demand-Control-Support Questionnaire, and the 12-item General Mental Health Questionnaire were distributed nationally. Univariate and multivariable regression models were used. Poorer mental health was associated with working with unaccompanied asylum-seeking refugee children among social workers but not among police officers. Psychological job demand was a significant predictor for general mental health among social workers, while psychological job demand, decision latitude, and marital status were predictors among police officers. Findings are discussed with special regard to the context of social work and police professions in Sweden. PMID:26153185

  3. Subharmonic Oscillations and Chaos in Dynamic Atomic Force Microscopy

    Science.gov (United States)

    Cantrell, John H.; Cantrell, Sean A.

    2015-01-01

    The increasing use of dynamic atomic force microscopy (d-AFM) for nanoscale materials characterization calls for a deeper understanding of the cantilever dynamics influencing scan stability, predictability, and image quality. Model development is critical to such understanding. Renormalization of the equations governing d- AFM provides a simple interpretation of cantilever dynamics as a single spring and mass system with frequency dependent cantilever stiffness and damping parameters. The renormalized model is sufficiently robust to predict the experimentally observed splitting of the free-space cantilever resonance into multiple resonances upon cantilever-sample contact. Central to the model is the representation of the cantilever sample interaction force as a polynomial expansion with coefficients F(sub ij) (i,j = 0, 1, 2) that account for the effective interaction stiffness parameter, the cantilever-to-sample energy transfer, and the amplitude of cantilever oscillation. Application of the Melnikov method to the model equation is shown to predict a homoclinic bifurcation of the Smale horseshoe type leading to a cascade of period doublings with increasing drive displacement amplitude culminating in chaos and loss of image quality. The threshold value of the drive displacement amplitude necessary to initiate subharmonic generation depends on the acoustic drive frequency, the effective damping coefficient, and the nonlinearity of the cantilever-sample interaction force. For parameter values leading to displacement amplitudes below threshold for homoclinic bifurcation other bifurcation scenarios can occur, some of which lead to chaos.

  4. Displacement cascades in diatomic materials

    International Nuclear Information System (INIS)

    Parkin, D.M.; Coulter, C.A.

    1981-01-01

    A new function, the specified-projectile displacement function p/sub ijk/ (E), is introduced to describe displacement cascades in polyatomic materials. This function describes the specific collision events that produce displacements and hence adds new information not previously available. Calculations of p/sub ijk/ (E) for MgO, Al 2 O 3 and TaO are presented and discussed. Results show that the parameters that have the largest effect on displacement collision events are the PKA energy and the mass ratio of the atom types in the material. It is further shown that the microscopic nature of the displacement events changes over the entire recoil energy range relevant to fusion neutron spectra and that these changes are different in materials whose mass ratio is near one than in those where it is far from one

  5. Resisting force characteristics of a mechanical snubber and its restraint effect on beam deformation

    International Nuclear Information System (INIS)

    Ohmata, Kenichiro

    1987-01-01

    A mechanical snubber is used to restrain piping systems in nuclear power plants during an earthquake. It has nonlinearities in both load (or exciting amplitude) and frequency response, so it will be very difficult to analyze the resisting force characteristics of the mechanical snubber theoretically. In this report, the equation of motion of the mechanical snubber is derived and digital simulations of snubber dynamic characteristics over a frequency range are carried out using the Continuous System Simulation Language (CSSL). Also, the restraint effect of the mechanical snubber applied to a simple beam is discussed both numerically and experimentally. The beam is replaced by a lumped mass system and CSSL is used to perform the digital simulations. (author)

  6. Nonlinear 2D arm dynamics in response to continuous and pulse-shaped force perturbations.

    Science.gov (United States)

    Happee, Riender; de Vlugt, Erwin; van Vliet, Bart

    2015-01-01

    Ample evidence exists regarding the nonlinearity of the neuromuscular system but linear models are widely applied to capture postural dynamics. This study quantifies the nonlinearity of human arm postural dynamics applying 2D continuous force perturbations (0.2-40 Hz) inducing three levels of hand displacement (5, 15, 45 mm RMS) followed by force-pulse perturbations inducing large hand displacements (up to 250 mm) in a position task (PT) and a relax task (RT) recording activity of eight shoulder and elbow muscles. The continuous perturbation data were used to analyze the 2D endpoint dynamics in the frequency domain and to identify reflexive and intrinsic parameters of a linear neuromuscular shoulder-elbow model. Subsequently, it was assessed to what extent the large displacements in response to force pulses could be predicted from the 'small amplitude' linear neuromuscular model. Continuous and pulse perturbation responses with varying amplitudes disclosed highly nonlinear effects. In PT, a larger continuous perturbation induced stiffening with a factor of 1.5 attributed to task adaptation evidenced by increased co-contraction and reflexive activity. This task adaptation was even more profound in the pulse responses where reflexes and displacements were strongly affected by the presence and amplitude of preceding continuous perturbations. In RT, a larger continuous perturbation resulted in yielding with a factor of 3.8 attributed to nonlinear mechanical properties as no significant reflexive activity was found. Pulse perturbations always resulted in yielding where a model fitted to the preceding 5-mm continuous perturbations predicted only 37% of the recorded peak displacements in RT and 79% in PT. This demonstrates that linear neuromuscular models, identified using continuous perturbations with small amplitudes, strongly underestimate displacements in pulse-shaped (e.g., impact) loading conditions. The data will be used to validate neuromuscular models including

  7. (Meta)cognitive beliefs in posttraumatic stress disorder following forced displacement at the end of the Second World War in older adults and their offspring.

    Science.gov (United States)

    Jelinek, Lena; Wittekind, Charlotte E; Kellner, Michael; Moritz, Steffen; Muhtz, Christoph

    2013-01-01

    The aim of the present study was to investigate (meta)cognitive beliefs related to posttraumatic stress disorder (PTSD) in a sample of individuals displaced as children at the end of the Second World War as well as transgenerational effects of trauma and PTSD on the offspring. Displaced individuals with (n=20) and without PTSD (n=24) and nondisplaced healthy controls (n=11), as well as one of their adult offspring, were assessed with the Metacognitions Questionnaire (MCQ-30). Older adults, formerly displaced in childhood, were additionally assessed with the Posttraumatic Cognitions Inventory (PTCI). Dysfunctional beliefs (MCQ-30, PTCI) were particularly pronounced in formerly displaced individuals with PTSD, but not in the offspring generation. The findings suggest that in an aging group of displaced individuals with PTSD dysfunctional beliefs are associated with the disorder. Bias modification may help to attenuate symptomatology. No evidence was found for a transgenerational effect.

  8. Modelling toehold-mediated RNA strand displacement.

    Science.gov (United States)

    Šulc, Petr; Ouldridge, Thomas E; Romano, Flavio; Doye, Jonathan P K; Louis, Ard A

    2015-03-10

    We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5' end of the substrate; and that the displacement slows down with increasing temperature for longer toeholds. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Gold and Displacement in Eastern Europe: Risks and Uncertainty at Roşia Montană

    Directory of Open Access Journals (Sweden)

    FILIP ALEXANDRESCU

    2011-01-01

    Full Text Available The Canadian-Romanian gold mining project at Roşia Montanǎ in Romania is known as the largest opencast gold mine being planned now in Europe. It involves the displacement of several thousand inhabitants, mostly former gold miners and a smaller number of farmers. The land and houses of more than three quarters of this population have already been acquired by the project owners, although the project has not yet received its formal environmental clearance. The paper analyzes the risks facing the displaced population of Roşia Montană, employing as analytical methodology the Impoverishment Risks and Reconstruction (IRR model, developed by Michael M. Cernea. The paper argues for an expansion of the IRR model. By taking into account the macro (extralocal forces that shape displacement and paying closer attention to the micro (subjective experience of this process, it becomes possible to understand the effects of uncertainty and vulnerability in displacement. The author's participant observations and in-depth interviews with local families are complemented with secondary analyses of data from several other socio-economic surveys and with the analysis of the Resettlement and Relocation Action Plan of the project owners.

  10. Online Image-based Monitoring of Soft-tissue Displacements for Radiation Therapy of the Prostate

    International Nuclear Information System (INIS)

    Schlosser, Jeffrey; Salisbury, Kenneth; Hristov, Dimitre

    2012-01-01

    Purpose: Emerging prolonged, hypofractionated radiotherapy regimens rely on high-dose conformality to minimize toxicity and thus can benefit from image guidance systems that continuously monitor target position during beam delivery. To address this need we previously developed, as a potential add-on device for existing linear accelerators, a novel telerobotic ultrasound system capable of real-time, soft-tissue imaging. Expanding on this capability, the aim of this work was to develop and characterize an image-based technique for real-time detection of prostate displacements. Methods and Materials: Image processing techniques were implemented on spatially localized ultrasound images to generate two parameters representing prostate displacements in real time. In a phantom and five volunteers, soft-tissue targets were continuously imaged with a customized robotic manipulator while recording the two tissue displacement parameters (TDPs). Variations of the TDPs in the absence of tissue displacements were evaluated, as was the sensitivity of the TDPs to prostate translations and rotations. Robustness of the approach to probe force was also investigated. Results: With 95% confidence, the proposed method detected in vivo prostate displacements before they exceeded 2.3, 2.5, and 2.8 mm in anteroposterior, superoinferior, and mediolateral directions. Prostate pitch was detected before exceeding 4.7° at 95% confidence. Total system time lag averaged 173 ms, mostly limited by ultrasound acquisition rate. False positives (FPs) (FP) in the absence of displacements did not exceed 1.5 FP events per 10 min of continuous in vivo imaging time. Conclusions: The feasibility of using telerobotic ultrasound for real-time, soft-tissue–based monitoring of target displacements was confirmed in vivo. Such monitoring has the potential to detect small clinically relevant intrafractional variations of the prostate position during beam delivery.

  11. Molecular displacement of warfarin from human serum albumin by flavonoid aglycones

    International Nuclear Information System (INIS)

    Poór, Miklós; Li, Yin; Kunsági-Máté, Sándor; Petrik, József; Vladimir-Knežević, Sanda; Kőszegi, Tamás

    2013-01-01

    The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs

  12. Molecular displacement of warfarin from human serum albumin by flavonoid aglycones

    Energy Technology Data Exchange (ETDEWEB)

    Poór, Miklós [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary); Li, Yin; Kunsági-Máté, Sándor [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); János Szentágothai Research Center, H-7624 Pécs (Hungary); Petrik, József [Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Vladimir-Knežević, Sanda [Department of Pharmacognosy, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Kőszegi, Tamás, E-mail: koszegit@freemail.hu [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary)

    2013-10-15

    The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs.

  13. Distraction of the temporomandibular joint condyle in patients with unilateral non-reducing disc displacement: Fact or fiction?

    Science.gov (United States)

    Yıldız, Melih; Çağatay Dayan, Süleyman; Şakar, Olcay; Sülün, Tonguç

    2017-07-24

    This study investigated the distractive effect of a unilateral pivot splint on patients with unilateral disc displacement without reduction. The study group was comprised of 18 patients who had no history of treatment with removable prosthetic restorations of molars, premolars, or canine teeth, and no previous treatment for temporomandibular disorder. Joint spaces measurements made on magnetic resonance images indicated the affected side to be narrower than the healthy side. Unilateral distraction splints were made for all patients. An ultrasonic motion analyzer was used to measure the vertical shift occurring on the affected side as patients closed their mouths with maximal force with the splint in their mouths. Closing with maximal force on the unilateral distraction splint led to a noticeable downward movement of the affected condyle. The findings of this study indicate that the TMJ condyle of patients with unilateral disc displacement without reduction may be unilaterally distracted if the articular space is narrowed.

  14. Demonstration of Vibrational Braille Code Display Using Large Displacement Micro-Electro-Mechanical Systems Actuators

    Science.gov (United States)

    Watanabe, Junpei; Ishikawa, Hiroaki; Arouette, Xavier; Matsumoto, Yasuaki; Miki, Norihisa

    2012-06-01

    In this paper, we present a vibrational Braille code display with large-displacement micro-electro-mechanical systems (MEMS) actuator arrays. Tactile receptors are more sensitive to vibrational stimuli than to static ones. Therefore, when each cell of the Braille code vibrates at optimal frequencies, subjects can recognize the codes more efficiently. We fabricated a vibrational Braille code display that used actuators consisting of piezoelectric actuators and a hydraulic displacement amplification mechanism (HDAM) as cells. The HDAM that encapsulated incompressible liquids in microchambers with two flexible polymer membranes could amplify the displacement of the MEMS actuator. We investigated the voltage required for subjects to recognize Braille codes when each cell, i.e., the large-displacement MEMS actuator, vibrated at various frequencies. Lower voltages were required at vibration frequencies higher than 50 Hz than at vibration frequencies lower than 50 Hz, which verified that the proposed vibrational Braille code display is efficient by successfully exploiting the characteristics of human tactile receptors.

  15. Lateral restorable characteristics of the high-Tc superconducting maglev vehicle above the permanent magnet guideway

    International Nuclear Information System (INIS)

    Ma, G.T.; Wang, J.S.; Lin, Q.X.; Liu, M.X.; Deng, Z.G.; Li, X.C.; Liu, H.F.; Zheng, J.; Wang, S.Y.

    2009-01-01

    The lateral restorable characteristics of a translational symmetry high-T c superconducting maglev system are investigated by measuring its resonant frequency (f RF ) after a lateral displacement. The difference between whether this lateral displacement is restorable, meaning elastic or inelastic, is determined by whether or not the maglev body returns to its original position after a lateral displacement. The maximum restorable lateral displacement (δ MRLD ) is determined by the sudden change of the f RF vs. the maximum lateral displacement (δ MLD ) curve. The f RF of the high-T c superconducting maglev system with different field-cooling height (FCH) and working height (WH) was obtained from the frequency domain vibration curve which was measured by a vibration measurement system. The results showed that, the δ MRLD was reduced when the WH was decreased. The maximum restorable guidance force (F MRGF ) was found to not always increase with the lowering of the WH for the same FCH. The lateral restorable stiffness (k LRS ) was always enhanced with the decrease of the WH. The decrease of the δ MRLD with the WH is interpreted by the fact that, the tangential field component (ΔH) across the surface of the high-T c superconductor (HTSC) is easier to exceed the J c λ value (J c is the critical current density and λ is the London penetration depth) when the WH is lowered, and this makes the trapped flux lines become more susceptible in escaping its pinning sites.

  16. Experimental test of static and dynamic characteristics of tilting-pad thrust bearings

    Directory of Open Access Journals (Sweden)

    Annan Guo

    2015-07-01

    Full Text Available The axial vibration in turbine machine has attracted more and more interest. Tilting-pad thrust bearings are widely used in turbine machines to support the axial load. The dynamic properties generated by oil film of the thrust pad have important effects on the axial vibration of the rotor-bearing system. It is necessary to develop the method to test the dynamic characteristics of thrust bearings. A new rig has been developed. The facility allows a complete set of bearing operating parameters to be measured. Parameters measured include oil temperatures, oil-film thickness, and pressure. The static load and dynamic load can be added on the thrust bearing in the vertical direction at the same time. The relative and absolute displacement vibrations of the test experimental bearing with the changes of dynamic force are measured, and the dynamic characteristics of the test bearing are obtained. The experimental results show clearly that the operating conditions influence largely on the pad static and dynamic characteristics.

  17. Limitations of radiographs in evaluating non-displaced osteochondral lesions of the talus

    Energy Technology Data Exchange (ETDEWEB)

    Dheer, Sachin [Department of Radiology, Kennedy Health System, Cherry Hill, NJ (United States); Khan, Mustafa [University of Toledo Medical Center, Department of Orthopedic Surgery, Toledo, OH (United States); Zoga, Adam C.; Morrison, William B. [Thomas Jefferson University Hospital, Department of Radiology, Philadelphia, PA (United States)

    2012-04-15

    To evaluate what limitations, if any, radiographs have in detecting and characterizing the morphology of non-displaced OCLTs (size, cystic change, fragmentation, and avascular necrosis [AVN]). Thirty-three OCLTs in 32 patients were reviewed in consensus by a board-certified, fellowship-trained musculoskeletal radiologist and orthopedic surgeon, on radiographs and MRI examinations performed within 15 days of one another. Location, dimensions, and characteristics of the OCLT (fragmentation, bone marrow edema, cystic change, and necrosis) were documented on the radiographs and MRI examinations. There was an average of 7.5 days (range: 1-15 days) between the MRIs and radiographs. Eighteen (55%) medial and 15 (45%) lateral OCLTs were found; none was displaced. OCLTs were categorized into three groups: Group 1 - initially diagnosed with radiographs (4/33; 12%), Group 2 - diagnosed with radiographs only after MRI correlation (20/33; 61%), and Group 3 - not identifiable on radiographs despite MRI correlation (9/33; 27%). The dimensions of all of the lesions in Groups 1 and 2 were underestimated on radiographs. Only 1 of the 4 (25%) lesions in Group 1 and 1 of the 20 (5%) lesions in Group 2 could be measured in the anteroposterior (AP) dimension (using a lateral radiograph). The most common radiographic appearance of non-displaced OCLTs was an ''ill-defined'' lucency at the talar dome (20/33; 61%). Across all three groups, fragmentation, cystic change, and AVN were radiographically apparent in 3/10 (30%), 4/19 (21%), and 1/6 (17%) cases respectively. Compared with MRI, radiographs are limited in their evaluation of the size (particularly the AP dimension) and characteristics (fragmentation, cystic change, and AVN) of non-displaced OCLTs. The most common appearance of non-displaced OCLTs is an ''ill-defined'' lucency at the talar dome. When this appearance is also considered, the estimated retrospective sensitivity of radiographs

  18. 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.)

  19. MRI of displaced meniscal fragments

    Energy Technology Data Exchange (ETDEWEB)

    Dunoski, Brian [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Children' s Hospital of Michigan, Department of Radiology, Detroit, MI (United States); Zbojniewicz, Andrew M.; Laor, Tal [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States)

    2012-01-15

    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.)

  20. Dynamic response of the JT-60 vacuum vessel under the electromagnetic forces

    International Nuclear Information System (INIS)

    Takatsu, H.; Shimizu, M.; Ohta, M.

    1982-01-01

    Dynamic response analyses of the JAERI Tokamak 60 (JT-60) vacuum vessel were carried out under three kinds of saddle-like electromagnetic forces. In the analysis, the dynamic response of the bellows was obtained by dividing it into three components; the first, caused by the forced deflection due to the displacement of an adjacent rigid ring; the second, caused by inertia force; and the third, caused by a saddle-like electromagnetic force. Eigenvalue analyses showed that the 20th mode is a typical rotation mode of the rigid ring around the major radius with a natural frequency of 46.3 Hz. From the results of the dynamic response analyses, the maximum displacement response of the rigid ring was 3.1 mm and remarkable dynamic response was observed in the case of plasma disruption with a time constant of 1 ms. In cases of start-up of the plasma current and plasma disruption with a time constant of 50 ms, the rigid ring vibrates quasi-statically. It is clear that the dynamic behavior of the vacuum vessel is governed mainly by the saddle-like electromagnetic force, with a smaller effect of the inverse saddle-like electromagnetic force on the dynamic response of the vacuum vessel. (orig.)

  1. Meshing Force of Misaligned Spline Coupling and the Influence on Rotor System

    Directory of Open Access Journals (Sweden)

    Guang Zhao

    2008-01-01

    Full Text Available Meshing force of misaligned spline coupling is derived, dynamic equation of rotor-spline coupling system is established based on finite element analysis, the influence of meshing force on rotor-spline coupling system is simulated by numerical integral method. According to the theoretical analysis, meshing force of spline coupling is related to coupling parameters, misalignment, transmitting torque, static misalignment, dynamic vibration displacement, and so on. The meshing force increases nonlinearly with increasing the spline thickness and static misalignment or decreasing alignment meshing distance (AMD. Stiffness of coupling relates to dynamic vibration displacement, and static misalignment is not a constant. Dynamic behaviors of rotor-spline coupling system reveal the following: 1X-rotating speed is the main response frequency of system when there is no misalignment; while 2X-rotating speed appears when misalignment is present. Moreover, when misalignment increases, vibration of the system gets intricate; shaft orbit departs from origin, and magnitudes of all frequencies increase. Research results can provide important criterions on both optimization design of spline coupling and trouble shooting of rotor systems.

  2. Computer simulation of local atomic displacements in alloys. Application to Guinier-Preston zones in Al-Cu

    International Nuclear Information System (INIS)

    Kyobu, J.; Murata, Y.; Morinaga, M.

    1994-01-01

    A new computer program has been developed for the simulation of local atomic displacements in alloys with face-centered-cubic and body-centered-cubic lattices. The combined use of this program with the Gehlen-Cohen program for the simulation of chemical short-range order completely describes atomic fluctuations in alloys. The method has been applied to the structural simulation of Guinier-Preston (GP) zones in an Al-Cu alloy, using the experimental data of Matsubara and Cohen. Characteristic displacements of atoms have been observed around the GP zones and new structural models including local displacements have been proposed for a single-layer zone and several multilayer zones. (orig.)

  3. Effects of threshold displacement energy on defect production by displacement cascades in α, β and γ-LiAlO2

    International Nuclear Information System (INIS)

    Tsuchihira, H.; Oda, T.; Tanaka, S.

    2013-01-01

    Threshold displacement energy evaluation and a series of displacement cascade simulations in α, β, and γ-LiAlO 2 were performed using molecular dynamics. Threshold displacement energy evaluations indicated that higher absolute ionic charge values and larger densities both increase threshold displacement energy. The displacement cascade simulations suggest that the influence of different crystal structures on the number of interstitial atoms generated in a displacement cascade is explainable almost entirely by the difference of the threshold displacement energy

  4. Effect of displaced versus non-displaced pelvic fractures on long-term racing performance in 31 Thoroughbred racehorses.

    Science.gov (United States)

    Hennessy, S E; Muurlink, M A; Anderson, G A; Puksmann, T N; Whitton, R C

    2013-06-01

    To evaluate the long-term racing prognosis for Thoroughbred racehorses with displaced versus non-displaced fractures of the pelvis identified by scintigraphy. Retrospective case analysis. Medical records of 31 Thoroughbred racehorses presenting to the University of Melbourne Equine Centre with fractures of the pelvis that were identified by scintigraphy were reviewed. Pelvic fracture site was determined and defined as displaced or non-displaced based on ultrasound and/or radiographic findings. Race records were analysed for each horse, with a minimum of 24 months' follow-up, and correlated with fracture type to determine long-term prognosis for racing. Results are expressed as median and range. Fractures at a single site were more common (n = 22) than fractures involving two sites (n = 9) and the ilial wing was the most commonly affected (n = 12). Thoroughbred racehorses with displaced pelvic fractures at any site (n = 12) raced fewer times within 24 months of diagnosis than horses with non-displaced fractures (n = 19) (median 0.5, range 0-13 vs 7, 0-24; P = 0.037), but there was no clear statistical difference in race earnings between the two groups (median A$0, range A$0-$123,250 vs A$14,440, A$0-$325,500, respectively; P = 0.080). Four horses with displaced fractures (33%) were euthanased on humane grounds because of persistent severe pain. When these horses were excluded from the analysis, there were no differences in performance variables between horses with a displaced or non-displaced pelvic fracture. Thoroughbred racehorses with a displaced or non-displaced pelvic fracture that survive the initial post-injury period have a good prognosis for racing. © 2013 The Authors. Australian Veterinary Journal © 2013 Australian Veterinary Association.

  5. Principle and Basic Characteristics of a Hybrid Variable-Magnetic-Force Motor

    Science.gov (United States)

    Sakai, Kazuto; Kuramochi, Satoru

    Reduction in the power consumed by motors is important for energy saving in the case of electrical appliances and electric vehicles (EVs). The motors used for operating these devices operate at variable speeds. Further, the motors operate with a small load in the stationary mode and a large load in the starting mode. A permanent magnet motor can be operated at the rated power with a high efficiency. However, the efficiency is low at a small load or at a high speed because the large constant magnetic force results in substantial core loss. Furthermore, the flux-weakening current that decreases the voltage at a high speed leads to significant copper loss and core loss. Therefore, we have developed a new technique for controlling the magnetic force of a permanent magnet on the basis of the load or speed of the motor. In this paper, we propose a novel motor that can vary the magnetic flux of a permanent magnet and clarify the principle and basic characteristics of the motor. The new motor has a permanent magnet that is magnetized by the magnetizing coil of the stator. The analysis results show that the magnetic flux linkage of the motor can be changed from 37% to 100% that a high torque can be produced.

  6. Simulation of dynamic behaviour of a digital displacement motor using transient 3d computational fluid dynamics analysis

    DEFF Research Database (Denmark)

    Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.

    2013-01-01

    . Movement of the low and high pressure valves is coupled to fluid forces and valve actuation is included to control the valve movement according to the pressure cycle of the digital displacement motor. The fluid domain is meshed using a structured/unstructured non-conformal mesh, which is updated throughout...

  7. A New Protection Orientation and Framework for Refugees and Other Forced Migrants

    Directory of Open Access Journals (Sweden)

    James C. Simeon

    2017-12-01

    Full Text Available The unprecedented current “refugee crisis,” with its 65 million plus uprooted people, demands a new protection orientation and framework for refugees and other forced migrants that are focused on the “root causes” of refugeehood, non-international protracted armed conflict or civil war. It is argued that four essential reforms are required to the international refugee protection system to respond to the “root causes” of refugees in the world today. The first calls for broadening the definition of who is a refugee to include “war refugees” as found in the 1984 Cartagena Declaration and the 1969 Organization of African Unity (OAU Convention. The 1984 Cartagena Declaration is preferred because it has the most progressive and broadest legal definition of who is a refugee and, therefore, should be emulated by all regions and the UNHCR internationally. The second reform would be the adoption of the Cartagena Declaration decennial consultation process and its comprehensive Plan of Action by the UNHCR on a global basis. This process has proven to be a success in Latin America and ought to be adopted internationally to develop and to realize the progressive advancement of international protection for all persons who are fleeing persecution and armed conflict. The third major reform is to develop the capacity of the UN to be able to operate in the midst of an armed conflict situation in order to broker a ceasefire and, then, negotiate a peace agreement, particularly, in those situations where massed forced displacement has taken place or potentially could take place. The fourth reform calls for the UN to expand the Responsibility to Protect (R2P doctrine to incorporate massed forced displacement, in addition to, war crimes, crimes against humanity, ethnic cleansing, and, genocide. This further implies that mass forced displacement ought to be criminalized and made a serious international crime, not simply in the international humanitarian

  8. Coulomb displacement energies in relativistic and non-relativistic self-consistent models

    International Nuclear Information System (INIS)

    Marcos, S.; Savushkin, L.N.; Giai, N. van.

    1992-03-01

    Coulomb displacement energies in mirror nuclei are comparatively analyzed in Dirac-Hartree and Skyrme-Hartree-Fock models. Using a non-linear effective Lagrangian fitted on ground state properties of finite nuclei, it is found that the predictions of relativistic models are lower than those of Hartree-Fock calculations with Skyrme force. The main sources of reduction are the kinetic energy and the Coulomb-nuclear interference potential. The discrepancy with the data is larger than in the Skyrme-Hartree-Fock case. (author) 24 refs., 3 tabs

  9. Changes in myosin S1 orientation and force induced by a temperature increase.

    Science.gov (United States)

    Griffiths, Peter J; Bagni, Maria A; Colombini, Barbara; Amenitsch, Heinz; Bernstorff, Sigrid; Ashley, Christopher C; Cecchi, Giovanni; Ameritsch, Heinz

    2002-04-16

    Force generation in myosin-based motile systems is thought to result from an angular displacement of the myosin subfragment 1 (S1) tail domain with respect to the actin filament axis. In muscle, raised temperature increases the force generated by S1, implying a greater change in tail domain angular displacement. We used time-resolved x-ray diffraction to investigate the structural corollary of this force increase by measuring M3 meridional reflection intensity during sinusoidal length oscillations. This technique allows definition of S1 orientation with respect to the myofilament axis. M3 intensity changes were approximately sinusoid at low temperatures but became increasingly distorted as temperature was elevated, with the formation of a double intensity peak at maximum shortening. This increased distortion could be accounted for by assuming a shift in orientation of the tail domain of actin-bound S1 toward the orientation at which M3 intensity is maximal, which is consistent with a tail domain rotation model of force generation in which the tail approaches a more perpendicular projection from the thin filament axis at higher temperatures. In power stroke simulations, the angle between S1 tail mean position during oscillations and the position at maximum intensity decreased by 4.7 degrees, corresponding to a mean tail displacement toward the perpendicular of 0.73 nm for a temperature-induced force increase of 0.28 P(0) from 4 to 22 degrees C. Our findings suggest that at least 62% of crossbridge compliance is associated with the tail domain.

  10. Recent Progress with the KWISP Force Sensor

    CERN Document Server

    Cantatore, G; Hoffmann, D.H.H.; Karuza, M.; Semertzidis, Y.K.; Zioutas, K.

    2015-01-01

    The KWISP opto-mechanical force sensor has been built and calibrated in the INFN Trieste optics laboratory and is now under off-beam commissioning at CAST. It is designed to detect the pressure exerted by a flux of solar Chameleons on a thin (100 nm) Si$_3$N$_4$ micromembrane thanks to their direct coupling to matter. A thermally-limited force sensitivity of $1.5 \\cdot 10^{-14}~\\mbox{N}/\\sqrt{\\mbox{Hz}}$, corresponding to $7.5 \\cdot 10^{-16}~\\mbox{m}/\\sqrt{\\mbox{Hz}}$ in terms of displacement, has been obtained. An originally developed prototype chameleon chopper has been used in combination with the KWISP force sensor to conduct preliminary searches for solar chamaleons.

  11. FINITE ELEMENT DISPLACEMENT PERTURBATION METHOD FOR GEOMETRIC NONLINEAR BEHAVIORS OF SHELLS OF REVOLUTION OVERALL BENDING IN A MERIDIONAL PLANE AND APPLICATION TO BELLOWS (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    朱卫平; 黄黔

    2002-01-01

    In order to analyze bellows effectively and practically, the finite-element-displacement-perturbation method (FEDPM) is proposed for the geometric nonlinearbehaviors of shells of revolution subjected to pure bending moments or lateral forces in one of their meridional planes. The formulations are mainly based upon the idea of perturba-tion that the nodal displacement vector and the nodal force vector of each finite elementare expanded by taking root-mean-square value of circumferential strains of the shells as aperturbation parameter. The load steps and the iteration times are not cs arbitrary andunpredictable as in usual nonlinear analysis. Instead, there are certain relations betweenthe load steps and the displacement increments, and no need of iteration for each loadstep. Besides, in the formulations, the shell is idealized into a series of conical frusta for the convenience of practice, Sander' s nonlinear geometric equations of moderate smallrotation are used, and the shell made of more than one material ply is also considered.

  12. Influence of the interatomic potentials on molecular dynamics simulations of displacement cascades

    CERN Document Server

    Becquart, C S; Legris, A; Van Duysen, J C

    2000-01-01

    Molecular dynamics (MD) is a powerful tool to study the displacement cascades initiated by the neutrons when they interact with matter. Key components of this technique are the interatomic potentials which model the binding of the different constitutive atoms. There exist many interatomic potentials dedicated to alpha-Fe and we have tested three of them for the study of radiation damage. We have found that the primary damage is potential sensitive. From our study, it appears that some characteristics of the potentials, not always considered, can be correlated to the type of damage produced by displacement cascades. The repulsive part of the potential has a strong influence on the cascade morphology. Moreover, equilibrium properties such as the atoms mean square displacements, the vacancy migration and vacancy-vacancy binding energies also appear to have some influence and should be investigated carefully when simulating radiation damage. It is therefore very important to use extreme care when trying to obtain...

  13. Experimental Study on the Properties and Displacement Effects of Polymer Surfactant Solution

    Directory of Open Access Journals (Sweden)

    Ke-Liang Wang

    2013-01-01

    Full Text Available Based on the characteristics of oil reservoirs and the requirements of further enhancing oil recovery at high water cut stage of Pubei Oilfield, the displacement performance of polymer surfactant is evaluated. Reasonable injection parameters and oil displacement effects after water flooding are also researched. Compared with conventional polymer with intermediate molecular weight, polymer surfactant has the properties of higher viscosity at low concentration condition and lower interfacial tension. Laboratory experiments indicate that the displacement effect of polymer surfactant is much better than that of conventional polymer at a slug size of 0.57 PV. The oil recovery of polymer surfactant increases by more than 10% after water flooding. Considering the actual situation of low-permeability of Pubei Oilfield reservoirs, the system viscosity of 30 mPa·s is chosen. The corresponding concentration of Type III polymer surfactant is 600 mg/L and the injected slug is 0.57 PV and the oil recovery can be increased by 11.69%.

  14. Fundamentals of displacement production in irradiated metals

    International Nuclear Information System (INIS)

    Doran, D.G.

    1975-09-01

    Radioinduced displacement damage in metals is described. Discussions are included on the displacement event itself, calculation of displacement rates in general, the manner in which different types of radiation interact with metals to produce displacements, the similarities and differences in the types of damage produced, the current status of computer simulations of displacement cascades, experimental evidence regarding cascades, and aspects of correlating damage produced by different types of radiation

  15. Influence of Ultrasonic Vibrations on the Static Friction Characteristics of a Rubber/Aluminum Couple

    International Nuclear Information System (INIS)

    Cheng Ting-Hai; Gao Han; Bao Gang

    2011-01-01

    A novel ultrasonic vibration approach is introduced into a chloroprene rubber/aluminum friction couple for improving the static friction properties between rubber and metal. Compared to the test results without vibrations, the static friction force of a chloroprene rubber/aluminum couple decreases observably, leading to the ultimate displacement of rubber. The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations, respectively. (fundamental areas of phenomenology(including applications))

  16. Modelling Toehold-Mediated RNA Strand Displacement

    OpenAIRE

    Šulc, Petr; Ouldridge, Thomas E.; Romano, Flavio; Doye, Jonathan P.K.; Louis, Ard A.

    2015-01-01

    We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperat...

  17. Important characteristics of operational force members

    CSIR Research Space (South Africa)

    Van Heerden, Adelai

    2017-10-01

    Full Text Available The operational forces military context is generally acknowledged as one of the most stressful contexts as it is demanding of members on a physical, psychological, social level with organisational, intra- and inter-personal demands of an extreme...

  18. Combined Discrete Space Voltage Vector with Direct Torque Control for Bearingless Brushless DC Motor and Closed-Loop Suspended Force Control

    Directory of Open Access Journals (Sweden)

    Weiran Wang

    2013-06-01

    Full Text Available In order to improve the performance of bearingless brushless DC motor, a closed-loop suspended force controller combining the discrete space voltage vector modulation is applied and the direct torque control is presented in this paper. Firstly, we increase the number of the control vector to reduce the torque ripple. Then, the suspending equation is constructed which is spired by the direct torque control algorithm. As a result, the closed-loop suspended force controller is built. The simulated and experimental results evaluate the performance of the proposed method. The more advantage is that the proposed algorithm can achieve the fast torque response, reduce the torque ripple, and follow ideal stator flux track. Furthermore, the motor which implants the closed-loop suspended force controller cannot onlyobtain the dynamic response rapidly and displacement control accurately, but also has the characteristics of bearingless brushless DC motor (such as simple structure, high energy efficiency, small volume and low failure rate.

  19. Biomechanical model-based displacement estimation in micro-sensor motion capture

    International Nuclear Information System (INIS)

    Meng, X L; Sun, S Y; Wu, J K; Zhang, Z Q; 3 Building, 21 Heng Mui Keng Terrace (Singapore))" data-affiliation=" (Department of Electrical and Computer Engineering, National University of Singapore (NUS), 02-02-10 I3 Building, 21 Heng Mui Keng Terrace (Singapore))" >Wong, W C

    2012-01-01

    In micro-sensor motion capture systems, the estimation of the body displacement in the global coordinate system remains a challenge due to lack of external references. This paper proposes a self-contained displacement estimation method based on a human biomechanical model to track the position of walking subjects in the global coordinate system without any additional supporting infrastructures. The proposed approach makes use of the biomechanics of the lower body segments and the assumption that during walking there is always at least one foot in contact with the ground. The ground contact joint is detected based on walking gait characteristics and used as the external references of the human body. The relative positions of the other joints are obtained from hierarchical transformations based on the biomechanical model. Anatomical constraints are proposed to apply to some specific joints of the lower body to further improve the accuracy of the algorithm. Performance of the proposed algorithm is compared with an optical motion capture system. The method is also demonstrated in outdoor and indoor long distance walking scenarios. The experimental results demonstrate clearly that the biomechanical model improves the displacement accuracy within the proposed framework. (paper)

  20. Measurement of interfacial displacement of a liquid film in microchannels using laser focus displacement meter

    International Nuclear Information System (INIS)

    Hazuku, Tatsuya; Fukamachi, Norihiro; Takamasa, Tomoji; Hibiki, Takashi

    2004-01-01

    This paper presents a new method for measuring the interfacial displacement of a liquid film in microchannels using a laser focus displacement meter (LFD). The purpose of the study is to clarify the effectiveness of the new method for obtaining detailed information concerning interfacial displacement, especially in the case of a thin liquid film, in micro- and mini-channels. To prevent the tube wall signal from disturbing that of the gas-liquid interface, a fluorocarbon tube with water box was used; the refraction index of this device is same as that for water. With this method, accurate instantaneous measurements of interfacial displacement of the liquid film were achieved. The error caused by refraction of the laser beam passing through the acrylic water box and fluorocarbon tube was estimated analytically and experimentally. The formulated analytical equation can estimate the real interface displacement using measured displacement in a fluorocarbon tube of 25 μm to 2.0 mm I.D. A preliminary test using fluorocarbon tubes of 1 and 2 mm I.D. showed that the corrected interface displacement calculated by the equation agreed with real displacement within a 1% margin of error. It was also confirmed that the LFD in the system could measure a liquid film of 0.25 μm at the thinnest. We made simultaneous measurements of the interface in fluorocarbon tubes of 0.5 and 1 mm I.D. using the LFD and a high-speed video camera with a microscope. These showed that the LFD could measure the interface of a liquid film with high spatial and temporal resolution during annular, slug, and piston flow regimes. The data also clarified the existence of a thin liquid film less than 1 μm in thickness in slug and annular flow regions. (author)

  1. Resonance-enhanced optical forces between coupled photonic crystal slabs.

    Science.gov (United States)

    Liu, Victor; Povinelli, Michelle; Fan, Shanhui

    2009-11-23

    The behaviors of lateral and normal optical forces between coupled photonic crystal slabs are analyzed. We show that the optical force is periodic with displacement, resulting in stable and unstable equilibrium positions. Moreover, the forces are strongly enhanced by guided resonances of the coupled slabs. Such enhancement is particularly prominent near dark states of the system, and the enhancement effect is strongly dependent on the types of guided resonances involved. These structures lead to enhancement of light-induced pressure over larger areas, in a configuration that is directly accessible to externally incident, free-space optical beams.

  2. Investigations on the acoustic optimisation of a variable displacement pump using virtual prototyping

    Directory of Open Access Journals (Sweden)

    Thomas NIED-MENNINGER

    2009-01-01

    Full Text Available In modern vehicles the steering systems are still widely equipped with power-assisted steering pumps. In most cases vane pumps are used which limit the fluid volume flow in dependence of required pressure and running speed by a special design of the internal control valve. This control valve internally redirects the volume flow inside the pump leading still to unnecessary fluid circulation. Variable displacement pumps now offer an additional opportunity to eliminate the internal volume flow in dependence of the required load with reduced losses and hence increased efficiency. This is realized by a variable adjustment of the displacement cells, but simultaneously the variable force and load distributions inside the pump make the acoustic optimization even more difficult. In this paper the kinematics of the vane pump are modelled with a combined analytical and numerical approach. The data out of this model are used as input data for the hydraulic model of the variable displacement vane pump with a commercial tool. Both models are validated with data from test rig investigations. With this validated virtual prototype different design options are developed and finally successfully investigated on a test rig and in a passenger vehicle.

  3. Validation of color Doppler sonography for evaluating relative displacement between the flexor tendon and subsynovial connective tissue.

    Science.gov (United States)

    Tat, Jimmy; Kociolek, Aaron M; Keir, Peter J

    2015-04-01

    A common pathologic finding in carpal tunnel syndrome is fibrosis and thickening of the subsynovial connective tissue. This finding suggests an etiology of excessive shear forces, with relative longitudinal displacement between the flexor tendon and adjacent subsynovial connective tissue. The purpose of this study was to validate color Doppler sonography for measurement of tendon displacement over time. Eight unmatched fresh frozen cadaver arms were used to evaluate color Doppler sonography for measurement of tendon displacement. The middle flexor digitorum superficialis tendon was moved through a physiologic excursion of 20 mm at 3 different tendon velocities (50, 100, and 150 mm/s). We found that color Doppler sonography provided accurate measurement of tendon displacement, with absolute errors of -0.05 mm (50 mm/s), -1.24 mm (100 mm/s), and -2.36 mm (150 mm/s) on average throughout the tendon excursion range. Evaluating relative displacement between the tendon and subsynovial connective tissue during finger flexion-extension movements also offered insight into the gliding mechanism of the subsynovial connective tissue. During flexion, we observed a curvilinear increase in relative displacement, with greater differential motion at the end range of displacement, likely due to the sequential stretch of the fibrils between successive layers of the subsynovial connective tissue. In extension, there was a linear return in relative displacement, suggesting a different unloading mechanism characterized by uniform relaxation of fibrils. We demonstrated the validity of color Doppler displacement for use in the evaluation of relative motion. Color Doppler sonography is useful in our understanding of the behavior of the subsynovial connective tissue during tendon excursion, which may elucidate the role of finger motion in the etiology of shear injury. © 2015 by the American Institute of Ultrasound in Medicine.

  4. Myofascial force transmission causes interaction between adjacent muscles and connective tissue: Effects of blunt dissection and compartmental fasciotomy on length force characteristics of rat extensor digitorum longus muscle

    NARCIS (Netherlands)

    Huijing, P.A.J.B.M.; Baan, G.C.

    2001-01-01

    Muscles within the anterior tibial compartment (extensor digitorum longus: EDL. tibialis anterior: TA, and extensor hallucis longus muscles: EHL) and within the peroneal compartment were excited simultaneously and maximally. The ankle joint was fixed kept at 90°. For EDL length force characteristics

  5. MEMS based Low Cost Piezoresistive Microcantilever Force Sensor and Sensor Module.

    Science.gov (United States)

    Pandya, H J; Kim, Hyun Tae; Roy, Rajarshi; Desai, Jaydev P

    2014-03-01

    In the present work, we report fabrication and characterization of a low-cost MEMS based piezoresistive micro-force sensor with SU-8 tip using laboratory made silicon-on-insulator (SOI) substrate. To prepare SOI wafer, silicon film (0.8 µm thick) was deposited on an oxidized silicon wafer using RF magnetron sputtering technique. The films were deposited in Argon (Ar) ambient without external substrate heating. The material characteristics of the sputtered deposited silicon film and silicon film annealed at different temperatures (400-1050°C) were studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The residual stress of the films was measured as a function of annealing temperature. The stress of the as-deposited films was observed to be compressive and annealing the film above 1050°C resulted in a tensile stress. The stress of the film decreased gradually with increase in annealing temperature. The fabricated cantilevers were 130 µm in length, 40 µm wide and 1.0 µm thick. A series of force-displacement curves were obtained using fabricated microcantilever with commercial AFM setup and the data were analyzed to get the spring constant and the sensitivity of the fabricated microcantilever. The measured spring constant and sensitivity of the sensor was 0.1488N/m and 2.7mV/N. The microcantilever force sensor was integrated with an electronic module that detects the change in resistance of the sensor with respect to the applied force and displays it on the computer screen.

  6. Comparison of Ground Reaction Forces, Center of Pressure and Body Center of Mass Changes in the Voluntary, Semi-Voluntary and Involuntary Gait Termination in Healthy Young Men

    Directory of Open Access Journals (Sweden)

    behrooz teymourian

    2016-03-01

    Full Text Available Objective: The aim of this study was comparing the ground reaction forces, center of pressure and body center of mass changes in voluntary, semi-voluntary and involuntary gait termination in healthy young men. Methods: In this study, 12 young men performed termination of gait in three different patterns. The variable of peak antero-posterior and vertical forces in two directions at both limbs, the time to reach peak and average forces in every limb in both directions, the center of pressure displacement of medio-lateral and antero-posterior direction for each limb and the net center of pressure and the displacement of the center of mass motion in all three motion plates were recorded using motion analysis system and force plate.The repeated measurements test was used to compare three patterns of gait termination at significance level of p&le0.5. Results: The results showed a significant difference in variables of peak antero-posterior force, the time to reach peak antero-posterior force and mean antero-posterior forces of the leading limb, the peak antero-posterior force of the trialing limbs, the depth force of leading limbs, medio-lateral cop of leading limbs displacement and vertical displacement of the center of mass, among different patterns of gait termination. Conclusion: While walking, the probability of a fall or collision damage, when a sudden or unexpected stop is required, increases. Therefore, more coordination between neuromuscular systems is required.

  7. Experimental study of airflow characteristics of stratum ventilation in a multi-occupant room with comparison to mixing ventilation and displacement ventilation.

    Science.gov (United States)

    Cheng, Y; Lin, Z

    2015-12-01

    The motivation of this study is stimulated by a lack of knowledge about the difference of airflow characteristics between a novel air distribution method [i.e., stratum ventilation (SV)] and conventional air distribution methods [i.e., mixing ventilation (MV) and displacement ventilation (DV)]. Detailed air velocity and temperature measurements were conducted in the occupied zone of a classroom with dimensions of 8.8 m (L) × 6.1 m (W) × 2.4 m (H). Turbulence intensity and power spectrum of velocity fluctuation were calculated using the measured data. Thermal comfort and cooling efficiency were also compared. The results show that in the occupied zone, the airflow characteristics among MV, DV, and SV are different. The turbulent airflow fluctuation is enhanced in this classroom with multiple thermal manikins due to thermal buoyancy and airflow mixing effect. Thermal comfort evaluations indicate that in comparison with MV and DV, a higher supply air temperature should be adopted for SV to achieve general thermal comfort with low draft risk. Comparison of the mean air temperatures in the occupied zone reveals that SV is of highest cooling efficiency, followed by DV and then MV. This study reports the unique profiles of flow, temperature, turbulence intensity, and power spectrum of stratum ventilation, which can have a number of implications for both knowledge and understanding of the flow characteristics in a stratum-ventilated room. With respect to the former, it expounds the fundamental characteristics of this air distribution method; and with respect to the latter, it reveals the mechanism of thermal comfort and energy saving under stratum ventilation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Fundamental principles of rotary displacement meters

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, J. [Schlumberger Industries, Owenton, KY (United States)

    1995-12-01

    The gas meter exists to continually and accurately measure the volume of gas supplied over the complete flow range of the load. In effect the gas meter serves as the {open_quotes}cash register{close_quotes} of the gas industry; its accurate and dependable performance ensures fair dealings for both the supplier and the user. An investment both in and of itself, the gas meter should be chosen as a function of its usefullness both over the short term and the long term. Thus in addition to initial cost, one must take into account various associated factors, costs and benefits, including the following: Design Characteristics Application, suitability, Meter features and options, Operation constraints, Installation, Service and maintenance, Repair and replacement, Life expectancy, Compatibility with complimentary products, Correcting devices, Remote reading capabilities, Data generation and gathering, Upgradeabilty. This paper will look at one positive displacement meter, the Rotary meter, and address the fundamentals principals of the technology as well as looking at some of the benefits derived from its application. Rotary positive displacement meters were introduced at the end of last century. Used primarily for metering transmission sized loads, the meters` measuring capabilities have extended to cover nearly all areas of distribution with exception of domestic applications. Rotary meters are available in rated capacities from 800 cfh to 102,000 cfh and operating pressures from 175 PSIG to 1440 PSIG. The use of rotary meters on load ranges in the 800 to 10,000 cfh category has increased and is replacing the use of diaphragm meters because of the smaller relative size of rotaries, and improvements in rangeabilities in the last few years. Turbine meters are usually the meter of choice on loads over 16,000 cfh unless a meter with high rangeability is required because of varying load characteristics, in which case a large foot mounted rotary might still be selected.

  9. Insomnia in a displaced population is related to war-associated remembered stress.

    Science.gov (United States)

    Basishvili, Tamar; Eliozishvili, Marine; Maisuradze, Lia; Lortkipanidze, Nani; Nachkebia, Nargiz; Oniani, Tengiz; Gvilia, Irma; Darchia, Nato

    2012-08-01

    Although traumatic events are presumed to cause sleep disturbances, particularly insomnia, sleep in populations subjected to forced displacement has received little attention. The present study examined the prevalence of insomnia and associated factors in internally displaced persons (IDPs) from Abkhazia 15 years after displacement to Tbilisi. Detailed subjective information about sleep-wake habits, sleep-related and stress-related parameters were obtained from 87 IDPs categorized into good sleepers and insomniacs. The Insomnia Severity Index, Perceived Stress Scale and Beck Depression Inventory were administered. The incidence of insomnia was 41.4%. The majority of insomniacs strongly believed that war-related stress accounted for the onset of their insomnia. Stepwise regression (95% confidence interval) revealed four variables significantly associated with insomnia status: self-estimated influence of war related stress (odds ratio (OR) = 2.51), frequency of nightmares (OR = 1.6), Perceived Stress Scale score (OR = 1.14) and Beck Depression Inventory score (OR = 1.12). Insomnia in IDPs was strongly related to war-associated remembered stress. ‛Over thinking' about major stress exposure enhanced IDPs' vulnerability to insomnia. These findings have implications for the management of insomnia and associated impairment of daytime functioning in IDPs. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays

    Science.gov (United States)

    Lu, S. G.; Chen, X.; Levard, T.; Diglio, P. J.; Gorny, L. J.; Rahn, C. D.; Zhang, Q. M.

    2015-06-01

    Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly.

  11. Displacement functions for diatomic materials

    International Nuclear Information System (INIS)

    Panrkin, D.M.; Coulter, C.A.

    1979-01-01

    An extension of the methods of Lindhard et at. was used to calculate the total displacement function n/sub ij/(E) for a number of diatomic materials, where n/sub ij/(E) is defined to be the average number of atoms of type j which are displaced from their sites in a displacement cascade initiated by a PKA of type i and energy E. From the n/sub ij/(E) one can calculate the fraction n/sub ij/(E) of the displacements produced by a type i PKA with energy E which are of type j. Values of the n/sub ij/ for MgO, CaO, Al 2 O 3 , and TaO are presented. It is shown that for diatomic materials with mass ratios reasonably near one (e.g., MgO, Al 2 O 3 ) and equal displacement thresholds for the two species the n/sub ij/ become independent of the PKA type i at energies only a few times threshold. However, for larger mass ratios the n/sub ij/ do not become independent of i until much larger, energies are reached - e.g. > 10 5 eV for TaO. In addition, it is found that the n/sub ij/ depend sensitively on the displacement thresholds, with very dramatic charges occuring when the two thresholds become significantly different from one another

  12. Stress distribution and displacement of maxillary anterior teeth during en-masse intrusion and retraction: A FEM study

    Directory of Open Access Journals (Sweden)

    Parag Bohara

    2017-01-01

    Full Text Available Background: Space closure by en masse intrusion and retraction in orthodontics is of particular interest. Aim: The aim of this study was to evaluate the stress distribution and displacement of maxillary anterior teeth. Materials and Methods: Four different finite element models of maxillary arch were constructed to understand the nature of stresses and displacement patterns of anterior teeth during en masse intrusion and retraction on force application with different combinations of mini-implants and retraction hooks. Results: In this study, tensile stresses were seen in the cervical region and various movements of teeth such as lingual crown tipping, bodily movement, lingual root tipping, intrusion, and extrusion were observed. Conclusion: Nature of stresses changes from tensile to compressive from cervical area to apical area. Various tooth displacements suggest that different combinations of mini-implants and retraction hooks affect the direction of the tooth movement.

  13. 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.

  14. Autologous nerve graft repair of different degrees of sciatic nerve defect:stress and displacement at the anastomosis in a three-dimensional finite element simulation model

    Institute of Scientific and Technical Information of China (English)

    Cheng-dong Piao; Kun Yang; Peng Li; Min Luo

    2015-01-01

    In the repair of peripheral nerve injury using autologous or synthetic nerve grafting, the mag-nitude of tensile forces at the anastomosis affects its response to physiological stress and the ultimate success of the treatment. One-dimensional stretching is commonly used to measure changes in tensile stress and strain; however, the accuracy of this simple method is limited. There-fore, in the present study, we established three-dimensional ifnite element models of sciatic nerve defects repaired by autologous nerve grafts. Using PRO E 5.0 ifnite element simulation software, we calculated the maximum stress and displacement of an anastomosis under a 5 N load in 10-, 20-, 30-, 40-mm long autologous nerve grafts. We found that maximum displacement increased with graft length, consistent with specimen force. These ifndings indicate that three-dimensional ifnite element simulation is a feasible method for analyzing stress and displacement at the anas-tomosis after autologous nerve grafting.

  15. Autologous nerve graft repair of different degrees of sciatic nerve defect: stress and displacement at the anastomosis in a three-dimensional fnite element simulation model

    Directory of Open Access Journals (Sweden)

    Cheng-dong Piao

    2015-01-01

    Full Text Available In the repair of peripheral nerve injury using autologous or synthetic nerve grafting, the magnitude of tensile forces at the anastomosis affects its response to physiological stress and the ultimate success of the treatment. One-dimensional stretching is commonly used to measure changes in tensile stress and strain however, the accuracy of this simple method is limited. Therefore, in the present study, we established three-dimensional finite element models of sciatic nerve defects repaired by autologous nerve grafts. Using PRO E 5.0 finite element simulation software, we calculated the maximum stress and displacement of an anastomosis under a 5 N load in 10-, 20-, 30-, 40-mm long autologous nerve grafts. We found that maximum displacement increased with graft length, consistent with specimen force. These findings indicate that three-dimensional finite element simulation is a feasible method for analyzing stress and displacement at the anastomosis after autologous nerve grafting.

  16. Conflict, displacement and health in the Middle East.

    Science.gov (United States)

    Mowafi, Hani

    2011-01-01

    Displacement is a hallmark of modern humanitarian emergencies. Displacement itself is a traumatic event that can result in illness or death. Survivors face challenges including lack of adequate shelter, decreased access to health services, food insecurity, loss of livelihoods, social marginalisation as well as economic and sexual exploitation. Displacement takes many forms in the Middle East and the Arab World. Historical conflicts have resulted in long-term displacement of Palestinians. Internal conflicts have driven millions of Somalis and Sudanese from their homes. Iraqis have been displaced throughout the region by invasion and civil strife. In addition, large numbers of migrants transit Middle Eastern countries or live there illegally and suffer similar conditions as forcibly displaced people. Displacement in the Middle East is an urban phenomenon. Many displaced people live hidden among host country populations in poor urban neighbourhoods - often without legal status. This represents a challenge for groups attempting to access displaced populations. Furthermore, health information systems in host countries often do not collect data on displaced people, making it difficult to gather data needed to target interventions towards these vulnerable populations. The following is a discussion of the health impacts of conflict and displacement in the Middle East. A review was conducted of published literature on migration and displacement in the region. Different cases are discussed with an emphasis on the recent, large-scale and urban displacement of Iraqis to illustrate aspects of displacement in this region.

  17. Realising traceable electrostatic forces despite non-linear balance motion

    International Nuclear Information System (INIS)

    Stirling, Julian; Shaw, Gordon A

    2017-01-01

    Direct realisation of force, traceable to fundamental constants via electromagnetic balances, is a key goal of the proposed redefinition of the international system of units (SI). This will allow small force metrology to be performed using an electrostatic force balance (EFB) rather than subdivision of larger forces. Such a balance uses the electrostatic force across a capacitor to balance an external force. In this paper we model the capacitance of a concentric cylinder EFB design as a function of the displacement of its free electrode, accounting for the arcuate motion produced by parallelogram linkages commonly used in EFB mechanisms. From this model we suggest new fitting procedures to reduce uncertainties arising from non-linear motion as well as methods to identify misalignment of the mechanism. Experimental studies on both a test capacitor and the NIST EFB validate the model. (paper)

  18. 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.

  19. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

    2015-06-22

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  20. Displaced squeezed number states: Position space representation, inner product, and some applications

    DEFF Research Database (Denmark)

    Møller, Klaus Braagaard; Jørgensen, Thomas Godsk; Dahl, Jens Peder

    1996-01-01

    For some applications the overall phase of a quantum state is crucial. For the so-called displaced squeezed number state (DSN), which is a generalization of the well-known squeezed coherent state, we obtain the position space representation with the correct overall phase, from the dynamics...... in a harmonic potential. The importance of the overall phase is demonstrated in the context of characteristic or moment generating functions. For two special cases the characteristic function is shown to be computable from the inner product of two different DSNs....

  1. X-ray determination of static displacements of atoms in alloyed Ni3Al

    International Nuclear Information System (INIS)

    Morinaga, M.; Sone, K.; Kamimura, T.; Ohtaka, K.; Yukawa, N.

    1988-01-01

    Single crystals of Ni 3 (Al, M) were grown by the Bridgman method, where M is Ti, V, Cr, Mn, Fe, Nb, Mo and Ta. The composition was controlled to be about Ni 75 Al 20 M 5 so that the alloying element, M, substitutes mainly for Al. With these crystals conventional X-ray structural analysis was performed. The measured static displacements of atoms from the average lattice points depended largely on the alloying elements and varied in the range 0.00-0.13 A for Ni atoms and 0.09-0.18 A for Al atoms. It was found that these atomic displacements correlated well with the atomic radius of the alloying element, M. For example, when the atomic radius of M is larger than that of Al, the static displacements are large for the atoms in the Al sublattice but small for the atoms in the Ni sublattice. By contrast, when the atomic radius of M is smaller than that of Al, the displacements are more enhanced in the Ni sublattice than in the Al sublattice. Thus, there is an interesting correlation between the atomic displacements in both the Al and Ni sublattices in the presence of alloying elements. This seems to be one of the characteristics of alloyed compounds with several sublattices. (orig.)

  2. 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

  3. A Force Method Model for Dynamic Analysis of Flat-Sag Cable Structures

    Directory of Open Access Journals (Sweden)

    Xing Ma

    2009-01-01

    Full Text Available A new force method is proposed for analysing the dynamic behaviour of oscillating cables with small sags. The accepted dynamic model of such cables reduces to a partial differential equation (the equation of motion and an integral equation (the compatibility equation. In the paper, D’Alembert’s travelling wave solution is applied to the partial differential equation (PDE. Substituting the solution into the compatibility and boundary conditions, the governing equation is obtained in terms of the dynamic tension increment. This equation has been named the force method dynamic equation (FMDE. In this way the infinite-degree-of-freedom dynamic system is effectively simplified to a system with only one unknown. Explicit solutions for both single-span and multi-span cable systems are derived. The natural frequencies obtained from the FMDE are shown to be identical to those deduced using the conventional displacement method (DM. Nonlinear governing equations are developed by considering the effect of quadratic and cubic displacement terms. Finally, two examples are presented to illustrate the accuracy of the proposed force method for single and multi-span cable systems subjected to harmonic forces.

  4. A high-force controllable MR fluid damper–liquid spring suspension system

    International Nuclear Information System (INIS)

    Raja, Pramod; Wang, Xiaojie; Gordaninejad, Faramarz

    2014-01-01

    The goal of the present research is to investigate the feasibility of incorporating a liquid spring in a semi-active suspension system for use in heavy off-road vehicles. A compact compressible magneto-rheological (MR) fluid damper–liquid spring (CMRFD–LS) with high spring rate is designed, developed and tested. Compressible MR fluids with liquid spring and variable damping characteristics are used. These fluids can offer unique functions in reducing the volume/weight of vehicle struts and improving vehicle dynamic stability and safety. The proposed device consists of a cylinder and piston–rod arrangement with an internal annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. Harmonic characterization of the CMRFD–LS is performed and the force–displacement results are presented. A fluid-mechanics based model is also developed to predict the performance of the system at different operating conditions and compared to the experimental results. Good agreement between the experimental results and theoretical predictions has been achieved. (paper)

  5. Optical tweezers for the measurement of binding forces: system description and application for the study of E. coli adhesion

    Science.gov (United States)

    Fallman, Erik G.; Schedin, Staffan; Andersson, Magnus J.; Jass, Jana; Axner, Ove

    2003-06-01

    Optical tweezers together with a position sensitive detection system allows measurements of forces in the pN range between micro-sized biological objects. A prototype force measurement system has been constructed around in inverted microscope with an argon-ion pumped Ti:sapphire laser as light source for optical trapping. A trapped particle in the focus of the high numerical aperture microscope-objective behaves like an omni-directional mechanical spring if an external force displaces it. The displacement from the equilibrium position is a measure of the exerted force. For position detection of the trapped particle (polystyrene beads), a He-Ne laser beam is focused a small distance below the trapping focus. An image of the bead appears as a distinct spot in the far field, monitored by a photosensitive detector. The position data is converted to a force measurement by a calibration procedure. The system has been used for measuring the binding forces between E-coli bacterial adhesin and their receptor sugars.

  6. CONCEPTUAL BASES OF FORMING THE SYSTEM OF FINANCIAL AND ECONOMIC PROVIDING SOCIAL PROTECTION INVOLUNTARILY DISPLACED PERSONS WITH CLUSTER APPROACH

    Directory of Open Access Journals (Sweden)

    Svitlana Kropelnytska

    2017-08-01

    Full Text Available The article systematizes approaches to financial support and social adaptation of internally displaced persons (IDPs as well as their social protection, that is based on the analysis of legal framework, situation and sources of financial and social support to the EU member states of the IDPs in Ukraine and their social security. The study of the IDPs situation and the assessment of the required resources are based on a cluster approach, which defines optimal set of problem areas requiring priority social and financial support. This allowed to develop practical recommendations for the development of a comprehensive, transparent and unified policy of social protection through the development of a conceptual framework for the financial and economic provision of social protection IDPs, which will be the basic solution to the problems of social and financial provision forced migrants in Ukraine. Key words: forced migrants, internally displaced persons, cluster, social policy, social protection, social providing, financial providing.

  7. A Basic Experiment on Two-Dimensional Force of HTSC-Bulk in DC Magnetic-Field

    OpenAIRE

    吉田, 欣二郎; 松田, 茂雄; 松本, 洋和

    2000-01-01

    High temperature superconducting (HTSC) bulk can levitate stably on a track which consists of permanent magnets of the same polarity. This is because HTSC-bulk has a pinning force which keeps from vertical displacement due to the weight. We have proposed a new LSM theory which is based on an idea of considering the pinning force as synchronizing force in using armature travelling-magnetic-field instead of permanent magnets. However, the lift force enough to levitate the vehicle on the ground ...

  8. The force pyramid: a spatial analysis of force application during virtual reality brain tumor resection.

    Science.gov (United States)

    Azarnoush, Hamed; Siar, Samaneh; Sawaya, Robin; Zhrani, Gmaan Al; Winkler-Schwartz, Alexander; Alotaibi, Fahad Eid; Bugdadi, Abdulgadir; Bajunaid, Khalid; Marwa, Ibrahim; Sabbagh, Abdulrahman Jafar; Del Maestro, Rolando F

    2017-07-01

    OBJECTIVE Virtual reality simulators allow development of novel methods to analyze neurosurgical performance. The concept of a force pyramid is introduced as a Tier 3 metric with the ability to provide visual and spatial analysis of 3D force application by any instrument used during simulated tumor resection. This study was designed to answer 3 questions: 1) Do study groups have distinct force pyramids? 2) Do handedness and ergonomics influence force pyramid structure? 3) Are force pyramids dependent on the visual and haptic characteristics of simulated tumors? METHODS Using a virtual reality simulator, NeuroVR (formerly NeuroTouch), ultrasonic aspirator force application was continually assessed during resection of simulated brain tumors by neurosurgeons, residents, and medical students. The participants performed simulated resections of 18 simulated brain tumors with different visual and haptic characteristics. The raw data, namely, coordinates of the instrument tip as well as contact force values, were collected by the simulator. To provide a visual and qualitative spatial analysis of forces, the authors created a graph, called a force pyramid, representing force sum along the z-coordinate for different xy coordinates of the tool tip. RESULTS Sixteen neurosurgeons, 15 residents, and 84 medical students participated in the study. Neurosurgeon, resident and medical student groups displayed easily distinguishable 3D "force pyramid fingerprints." Neurosurgeons had the lowest force pyramids, indicating application of the lowest forces, followed by resident and medical student groups. Handedness, ergonomics, and visual and haptic tumor characteristics resulted in distinct well-defined 3D force pyramid patterns. CONCLUSIONS Force pyramid fingerprints provide 3D spatial assessment displays of instrument force application during simulated tumor resection. Neurosurgeon force utilization and ergonomic data form a basis for understanding and modulating resident force

  9. Forced vibration analysis of a Timoshenko cracked beam using a continuous model for the crack

    Directory of Open Access Journals (Sweden)

    Mahdi Heydari

    2014-12-01

    Full Text Available In this paper, forced flexural vibration of a cracked beam is studied by using a continuous bilinear model for the displacement field. The effects of shear deformation and rotary inertia are considered in the model. The governing equation of motion for the beam is obtained using the Hamilton principle and based on the proposed displacement field. The equation of motion is given for a general force distribution. Then, the equation of motion has been solved for a concentrated force to present a numerical simulation of the method. The frequency response diagrams obtained from this study are compared with the finite element results to demonstrate the accuracy of the method. The results are also compared to results of a similar model with Euler-Bernoulli assumptions to confirm the advantages of the proposed model in the case of short beams.

  10. Characteristic Analysis and Simulated Test of Hybrid Bearing with the Introduction of Piezoelectric Controller

    Directory of Open Access Journals (Sweden)

    Runlin Chen

    2016-01-01

    Full Text Available A novel hybrid bearing with the introduction of piezoelectric controller and tilting pads to control vibration actively is proposed in this paper, and the feasibility of this scheme is verified by theoretical calculation and experimental data. This scheme can control the vibration of bearing actively by using the electromechanical characteristics of piezoelectric ceramic transducer (PZT components. The static internal character of PZT and static external characteristic of piezoelectric control component are analyzed, and the calculation equations of preload coefficient and driving force of the new bearing are given. The simulation setup of the new bearing is designed and developed. The data representing the relationship of displacement of pad pivot, driving force, voltage, and the simulation stiffness of liquid film are obtained in the test, and the feature parameters of piezoelectric control component are amended to analyze the relationship between preload coefficient of the bearing and driving voltage. The proposed new bearing has the function of controlling preload actively. The theoretical and experimental research results provide essential guidance for the detail design of this new bearing and also provide a new idea for the vibration control of high speed rotor systems.

  11. Peroneal tendon displacement accompanying intra-articular calcaneal fractures.

    Science.gov (United States)

    Toussaint, Rull James; Lin, Darius; Ehrlichman, Lauren K; Ellington, J Kent; Strasser, Nicholas; Kwon, John Y

    2014-02-19

    Peroneal tendon displacement (subluxation or dislocation) accompanying an intra-articular calcaneal fracture is often undetected and under-treated. The goals of this study were to determine (1) the prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures, (2) the association of tendon displacement with fracture classifications, (3) the association of tendon displacement with heel width, and (4) the rate of missed diagnosis of the tendon displacement on radiographs and computed tomography (CT) scans and the resulting treatment rate. A retrospective radiographic review of all calcaneal fractures presenting at three institutions from June 30, 2006, to June 30, 2011, was performed. CT imaging of 421 intra-articular calcaneal fractures involving the posterior facet was available for review. The prevalence of peroneal tendon displacement was noted and its associations with fracture classification and heel width were evaluated. Peroneal tendon displacement was identified in 118 (28.0%) of the 421 calcaneal fracture cases. The presence of tendon displacement was significantly associated with joint-depression fractures compared with tongue-type fractures (p displacement had been identified in the radiology reports. Although sixty-five (55.1%) of the fractures with tendon displacement had been treated with internal fixation, the tendon displacement was treated surgically in only seven (10.8%) of these cases. Analysis of CT images showed a 28% prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures. Surgeons and radiologists are encouraged to consider this association.

  12. Haptic device development based on electro static force of cellulose electro active paper

    Science.gov (United States)

    Yun, Gyu-young; Kim, Sang-Youn; Jang, Sang-Dong; Kim, Dong-Gu; Kim, Jaehwan

    2011-04-01

    Haptic is one of well-considered device which is suitable for demanding virtual reality applications such as medical equipment, mobile devices, the online marketing and so on. Nowadays, many of concepts for haptic devices have been suggested to meet the demand of industries. Cellulose has received much attention as an emerging smart material, named as electro-active paper (EAPap). The EAPap is attractive for mobile haptic devices due to its unique characteristics in terms of low actuation power, suitability for thin devices and transparency. In this paper, we suggest a new concept of haptic actuator with the use of cellulose EAPap. Its performance is evaluated depending on various actuation conditions. As a result, cellulose electrostatic force actuator shows a large output displacement and fast response, which is suitable for mobile haptic devices.

  13. Lateral shearing optical gradient force in coupled nanobeam photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Du, Han; Zhang, Xingwang; Chau, Fook Siong; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575 (Singapore); Deng, Jie [Institute of Materials Research and Engineering, 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Zhao, Yunshan [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583 (Singapore)

    2016-04-25

    We report the experimental observation of lateral shearing optical gradient forces in nanoelectromechanical systems (NEMS) controlled dual-coupled photonic crystal (PhC) nanobeam cavities. With an on-chip integrated NEMS actuator, the coupled cavities can be mechanically reconfigured in the lateral direction while maintaining a constant coupling gap. Shearing optical gradient forces are generated when the two cavity centers are laterally displaced. In our experiments, positive and negative lateral shearing optical forces of 0.42 nN and 0.29 nN are observed with different pumping modes. This study may broaden the potential applications of the optical gradient force in nanophotonic devices and benefit the future nanooptoelectromechanical systems.

  14. CRANIOFACIAL STRESS PATTERNS AND DISPLACEMENTS AFTER ACTIVATION OF HYRAX DEVICE: FINITE ELEMENT MODELLING

    Directory of Open Access Journals (Sweden)

    Sergei Bosiakov

    2017-12-01

    Full Text Available Rapid maxillary expansion is employed for the treatment of cross-bite and deficiency of transversal dimension of the maxilla in patients with and without cleft of palate and lip. For this procedure, generally, different orthodontic appliances and devices generating significant transversal forces are used. The aim of this study is the finite-element analysis of stresses and displacements of the skull without palate cleft and the skull with unilateral and bilateral cleft after activation of the Hyrax orthodontic device. Two different constructions of the orthodontic device Hyrax with different positions of the screw relative palate are considered. In the first case, the screw is in the occlusal horizontal plane, and in the other, the screw is located near the palate. Activation of the orthodontic device corresponds to the rotation of the screw on one-quarter turn. It is established that the screw position significantly affects the distributions of stresses in skull and displacements of the cranium without palate cleft and with unilateral or bilateral palate cleft. Stresses in the bone structures of the craniums without cleft and with cleft are transferred from the maxilla to the pterygoid plate and pharyngeal tubercle if the screw displaces from the occlusal plane to the palate. Depending on the construction of the orthodontic appliance, the maxilla halves in the transversal plane are unfolded or the whole skull is entirely rotated in the sagittal plane. The stresses patterns and displacements of the skull with bilateral palate cleft are almost unchanged after activation of the orthodontic devices with different positions of the screw, only magnitudes of stresses and displacements are changed. The obtained results can be used for design of orthodontic appliances with the Hyrax screw, as well as for planning of osteotomies during the surgical assistance of the rapid maxillary expansion.

  15. 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.

  16. Heartbeat-related displacement of the thoracic aorta in patients with chronic aortic dissection type B: Quantification by dynamic CTA

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Tim F. [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)], E-mail: tim.weber@med.uni-heidelberg.de; Ganten, Maria-Katharina [German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)], E-mail: m.ganten@dkfz.de; Boeckler, Dittmar [University of Heidelberg, Department of Vascular and Endovascular Surgery, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)], E-mail: dittmar.boeckler@med.uni-heidelberg.de; Geisbuesch, Philipp [University of Heidelberg, Department of Vascular and Endovascular Surgery, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)], E-mail: philipp.geisbuesch@med.uni-heidelberg.de; Kauczor, Hans-Ulrich [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)], E-mail: hu.kauczor@med.uni-heidelberg.de; Tengg-Kobligk, Hendrik von [German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)], E-mail: h.vontengg@dkfz.de

    2009-12-15

    Purpose: The purpose of this study was to characterize the heartbeat-related displacement of the thoracic aorta in patients with chronic aortic dissection type B (CADB). Materials and methods: Electrocardiogram-gated computed tomography angiography was performed during inspiratory breath-hold in 11 patients with CADB: Collimation 16 mm x 1 mm, pitch 0.2, slice thickness 1 mm, reconstruction increment 0.8 mm. Multiplanar reformations were taken for 20 equidistant time instances through both ascending (AAo) and descending aorta (true lumen, DAoT; false lumen, DAoF) and the vertex of the aortic arch (VA). In-plane vessel displacement was determined by region of interest analysis. Results: Mean displacement was 5.2 {+-} 1.7 mm (AAo), 1.6 {+-} 1.0 mm (VA), 0.9 {+-} 0.4 mm (DAoT), and 1.1 {+-} 0.4 mm (DAoF). This indicated a significant reduction of displacement from AAo to VA and DAoT (p < 0.05). The direction of displacement was anterior for AAo and cranial for VA. Conclusion: In CADB, the thoracic aorta undergoes a heartbeat-related displacement that exhibits an unbalanced distribution of magnitude and direction along the thoracic vessel course. Since consecutive traction forces on the aortic wall have to be assumed, these observations may have implications on pathogenesis of and treatment strategies for CADB.

  17. Searching for displaced Higgs boson decays

    Science.gov (United States)

    Csáki, Csaba; Kuflik, Eric; Lombardo, Salvator; Slone, Oren

    2015-10-01

    We study a simplified model of the Standard Model (SM) Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs boson decays below 10 cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at √{s }=13 TeV . With 20 fb-1 of data, we find that Higgs branching ratios down to 2 ×1 0-4 can be probed for centimeter decay lengths.

  18. 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

  19. Can the real opportunity cost stand up: displaced services, the straw man outside the room.

    Science.gov (United States)

    Eckermann, Simon; Pekarsky, Brita

    2014-04-01

    In current literature, displaced services have been suggested to provide a basis for determining a threshold value for the effects of a new technology as part of a reimbursement process when budgets are fixed. We critically examine the conditions under which displaced services would represent an economically meaningful threshold value. We first show that if we assume that the least cost-effective services are displaced to finance a new technology, then the incremental cost-effectiveness ratio (ICER) of the displaced services (d) only coincides with that related to the opportunity cost of adopting that new technology, the ICER of the most cost-effective service in expansion (n), under highly restrictive conditions-namely, complete allocative efficiency in existing provision of health care interventions. More generally, reimbursement of new technology with a fixed budget comprises two actions; adoption and financing through displacement and the effect of reimbursement is the net effect of these two actions. In order for the reimbursement process to be a pathway to allocative efficiency within a fixed budget, the net effect of the strategy of reimbursement is compared with the most cost-effective alternative strategy for reimbursement: optimal reallocation, the health gain maximizing expansion of existing services financed by the health loss minimizing contraction. The shadow price of the health effects of a new technology, βc = (1/n + 1/d - 1/m)(-1), accounts for both imperfect displacement (the ICER of the displaced service, d < m, the ICER of the least cost-effective of the existing services in contraction) and the allocative inefficiency (n < m) characteristic of health systems.

  20. Backscattering position detection for photonic force microscopy

    International Nuclear Information System (INIS)

    Volpe, Giovanni; Kozyreff, Gregory; Petrov, Dmitri

    2007-01-01

    An optically trapped particle is an extremely sensitive probe for the measurement of pico- and femto-Newton forces between the particle and its environment in microscopic systems (photonic force microscopy). A typical setup comprises an optical trap, which holds the probe, and a position sensing system, which uses the scattering of a beam illuminating the probe. Usually the position is accurately determined by measuring the deflection of the forward-scattered light transmitted through the probe. However, geometrical constraints may prevent access to this side of the trap, forcing one to make use of the backscattered light instead. A theory is presented together with numerical results that describes the use of the backscattered light for position detection. With a Mie-Debye approach, we compute the total (incident plus scattered) field and follow its evolution as it is collected by the condenser lenses and projected onto the position detectors and the responses of position sensitive detectors and quadrant photodetectors to the displacement of the probe in the optical trap, both in forward and backward configurations. We find out that in the case of backward detection, for both types of detectors the displacement sensitivity can change sign as a function of the probe size and is null for some critical sizes. In addition, we study the influence of the numerical aperture of the detection system, polarization, and the cross talk between position measurements in orthogonal directions. We finally discuss how these features should be taken into account in experimental designs

  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. Characteristics of a random force in the phenomenological description of surface oscillations of heated spherical nuclei

    International Nuclear Information System (INIS)

    Svin'in, I.R.

    1987-01-01

    A method of calculation of statistical characteristics of a random force is presented. This method is used in the description of oscillations of heated spherical nuclei in the Brownian movement approximation. The mean value and the spectral density of the correlation function are calculated in the noninteracting-particle model. The dependence of the spectral density on the number of nucleons and on the temperature of the nucleus is analyzed

  3. Update of distillers grains displacement ratios for corn ethanol life-cycle analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Arora, S.; Wu, M.; Wang, M.; Energy Systems

    2011-02-01

    Production of corn-based ethanol (either by wet milling or by dry milling) yields the following coproducts: distillers grains with solubles (DGS), corn gluten meal (CGM), corn gluten feed (CGF), and corn oil. Of these coproducts, all except corn oil can replace conventional animal feeds, such as corn, soybean meal, and urea. Displacement ratios of corn-ethanol coproducts including DGS, CGM, and CGF were last updated in 1998 at a workshop at Argonne National Laboratory on the basis of input from a group of experts on animal feeds, including Prof. Klopfenstein (University of Nebraska, Lincoln), Prof. Berger (University of Illinois, Urbana-Champaign), Mr. Madson (Rapheal Katzen International Associates, Inc.), and Prof. Trenkle (Iowa State University) (Wang 1999). Table 1 presents current dry milling coproduct displacement ratios being used in the GREET model. The current effort focuses on updating displacement ratios of dry milling corn-ethanol coproducts used in the animal feed industry. Because of the increased availability and use of these coproducts as animal feeds, more information is available on how these coproducts replace conventional animal feeds. To glean this information, it is also important to understand how industry selects feed. Because of the wide variety of available feeds, animal nutritionists use commercial software (such as Brill Formulation{trademark}) for feed formulation. The software recommends feed for the animal on the basis of the nutritional characteristics, availability, and price of various animal feeds, as well as on the nutritional requirements of the animal (Corn Refiners Association 2006). Therefore, feed formulation considers both the economic and the nutritional characteristics of feed products.

  4. Nanometer-scale displacement measurement with high resolution using dual cavity Fabry-Pérot interferometer for biomimetic robots.

    Science.gov (United States)

    Lee, Jin-Hyuk; Kim, Dae-Hyun

    2014-10-01

    A sensor of a biomimetic robot has to measure very small environmental changes such as, nanometer scale strains or displacements. Fiber optic sensor can be also one of candidates for the biomimetic sensor because the sensor is like thread and the shape of the sensor is similar to muscle fiber. A fiber optic interferometer, which is an optical-based sensor, can measure displacement precisely, so such device has been widely studied for the measurement of displacement on a nanometer-scale. Especially, a Quadrature Phase-Shifted Fiber Fabry-Pérot interferometer (QPS-FFPI) uses phase-information for this measurement, allowing it to provide a precision result with high resolution. In theory, the QPS-FFPI generates two sinusoidal signals of which the phase difference should be 90 degrees for the exact measurement of the displacement. In order to guarantee the condition of the phase difference, the relative adjustment of the cavities of the optical fibers is required. However, with such precise adjustment it is very hard to fix the proper difference of the two cavities for quadrature-phase-shifting. In this paper, a dual-cavity FFPI is newly proposed to measure the displacement on a nanometer-scale with a specific type of signal processing. In the signal processing, a novel phase-compensation algorithm is applied to force the phase difference to be exactly 90 degrees without any physical adjustment. As a result, the paper shows that the phase-compensated dual-cavity FFPI can effectively measure nanometer-scale displacement with high resolution under dynamic conditions.

  5. Games to familiarize children of 7-9 years old with the displacements of Badminton

    Directory of Open Access Journals (Sweden)

    Ayran Arencibia Moreno

    2016-12-01

    Full Text Available In order that Badminton’s athlete manages to join the technical elements displacements are indispensable, that´s why this research shows the experience carried out to a group of 7-9 year-old children to familiarize them with the displacements in the sport Badminton, considering the difficulties they presented to dominate them. The purpose of the work focuses in proposing games that contribute to improve the assimilation of the displacements technique in Badminton teaching – learning process in these ages. To get the purpose theoretical and empiric methods were used, among the empirical ones the observation and the interview were used. In the content of the work some theoretical referents on the games and their use in the teaching of these sport basic technical skills are assumed, also it is given the physiologic and psychological characteristics of the group studied, as well as a group of 10 pre-sport games for the teaching of the displacements. The application of these games in the practice, starting from their structure, understanding and easy performance has allowed a better assimilation of the technical contents taught to the group studied.

  6. Nanonewton force measurement using a modified Michelson interferometer

    International Nuclear Information System (INIS)

    Tahviliyan, Masoud; Charsooghi, Mohammad A; Akhlaghi, Ehsan A; Taghi Tavassoly, Mohammad

    2017-01-01

    In this paper, we introduce a new method to measure forces in the nanonewton range. The method is based on modification of a Michelson interferometer in which the rigid mirrors are replaced with two thin rod-like mirrors. One of the rod-like mirrors is fixed at both ends and the other has one free end. As the mirror with free end deflects in response to an applied force the spatial interference pattern is changed. Analysis of the interference fringes provides a readout of the rod deflection and thereby the applied force. The device is calibrated by applying known forces to the mirror with a free end and measuring the resulting displacement. Two different methods, mechanical and electrostatic, are used for calibration. The precision of the measurements and the propagation of the calibration uncertainty are investigated. The results show that this optical method is a good candidate for detecting small forces in the nanonewton range. (paper)

  7. Validation of the force and frequency characteristics of the activator adjusting instrument: effectiveness as a mechanical impedance measurement tool.

    Science.gov (United States)

    Keller, T S; Colloca, C J; Fuhr, A W

    1999-02-01

    To determine the dynamic force-time and force-frequency characteristics of the Activator Adjusting Instrument and to validate its effectiveness as a mechanical impedance measurement device; in addition, to refine or optimize the force-frequency characteristics of the Activator Adjusting Instrument to provide enhanced dynamic structural measurement reliability and accuracy. An idealized test structure consisting of a rectangular steel beam with a static stiffness similar to that of the human thoracolumbar spine was used for validation of a method to determine the dynamic mechanical response of the spine. The Activator Adjusting Instrument equipped with a load cell and accelerometer was used to measure forces and accelerations during mechanical excitation of the steel beam. Driving point and transfer mechanical impedance and resonant frequency of the beam were determined by use of a frequency spectrum analysis for different force settings, stylus masses, and stylus tips. Results were compared with beam theory and transfer impedance measurements obtained by use of a commercial electronic PCB impact hammer. The Activator Adjusting Instrument imparted a very complex dynamic impact comprising an initial high force (116 to 140 N), short duration pulse (analysis of the Activator Adjusting Instrument impulse indicated that the Activator Adjusting Instrument has a variable force spectrum and delivers its peak energy at a frequency of 20 Hz. Added masses and different durometer stylus tips had very little influence on the Activator Adjusting Instrument force spectrum. The resonant frequency of the beam was accurately predicted by both the Activator Adjusting Instrument and electronic PCB impact hammer, but variations in the magnitude of the driving point impedance at the resonant frequency were high (67%) compared with the transfer impedance measurements obtained with the electronic PCB impact hammer, which had a more uniform force spectrum and was more repeatable (frequency

  8. Competitive displacement of sodium caseinate by low-molecular-weight emulsifiers and the effects on emulsion texture and rheology.

    Science.gov (United States)

    Munk, M B; Larsen, F H; van den Berg, F W J; Knudsen, J C; Andersen, M L

    2014-07-29

    Low-molecular-weight (LMW) emulsifiers are used to promote controlled destabilization in many dairy-type emulsions in order to obtain stable foams in whippable products. The relation between fat globule aggregation induced by three LMW emulsifiers, lactic acid ester of monoglyceride (LACTEM), saturated monoglyceride (GMS), and unsaturated monoglyceride (GMU) and their effect on interfacial protein displacement was investigated. It was found that protein displacement by LMW emulsifiers was not necessary for fat globule aggregation in emulsions, and conversely fat globule aggregation was not necessarily accompanied by protein displacement. The three LMW emulsifiers had very different effects on emulsions. LACTEM induced shear instability of emulsions, which was accompanied by protein displacement. High stability was characteristic for emulsions with GMS where protein was displaced from the interface. Emulsions containing GMU were semisolid, but only low concentrations of protein were detected in the separated serum phase. The effects of LACTEM, GMS, and GMU may be explained by three different mechanisms involving formation of interfacial α-gel, pickering stabilization and increased exposure of bound casein to the water phase. The latter may facilitate partial coalescence. Stabilizing hydrocolloids did not have any effect on the LMW emulsifiers' ability to induce protein displacement.

  9. Atomic-scale nanoindentation: detection and identification of single glide events in three dimensions by force microscopy

    International Nuclear Information System (INIS)

    Egberts, P; Bennewitz, R

    2011-01-01

    Indentation experiments on the nanometre scale have been performed by means of atomic force microscopy in ultra-high vacuum on KBr(100) surfaces. The surfaces yield in the form of discrete surface displacements with a typical length scale of 1 A. These surface displacements are detected in both normal and lateral directions. Measurement of the lateral tip displacement requires a load-dependent calibration due to the load dependence of the effective lateral compliance. Correlation of the lateral and normal displacements for each glide event allow identification of the activated slip system. The results are discussed in terms of the resolved shear stress in indentation experiments and of typical results in atomistic simulations of nanometre-scale indentation.

  10. Adaptive sliding mode back-stepping pitch angle control of a variable-displacement pump controlled pitch system for wind turbines.

    Science.gov (United States)

    Yin, Xiu-xing; Lin, Yong-gang; Li, Wei; Liu, Hong-wei; Gu, Ya-jing

    2015-09-01

    A variable-displacement pump controlled pitch system is proposed to mitigate generator power and flap-wise load fluctuations for wind turbines. The pitch system mainly consists of a variable-displacement hydraulic pump, a fixed-displacement hydraulic motor and a gear set. The hydraulic motor can be accurately regulated by controlling the pump displacement and fluid flows to change the pitch angle through the gear set. The detailed mathematical representation and dynamic characteristics of the proposed pitch system are thoroughly analyzed. An adaptive sliding mode pump displacement controller and a back-stepping stroke piston controller are designed for the proposed pitch system such that the resulting pitch angle tracks its desired value regardless of external disturbances and uncertainties. The effectiveness and control efficiency of the proposed pitch system and controllers have been verified by using realistic dataset of a 750 kW research wind turbine. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Research on Multiple-Split Load Sharing Characteristics of 2-Stage External Meshing Star Gear System in Consideration of Displacement Compatibility

    Directory of Open Access Journals (Sweden)

    Shuai Mo

    2017-01-01

    Full Text Available This paper studies the multiple-split load sharing mechanism of gears in two-stage external meshing planetary transmission system of aeroengine. According to the eccentric error, gear tooth thickness error, pitch error, installation error, and bearing manufacturing error, we performed the meshing error analysis of equivalent angles, respectively, and we also considered the floating meshing error caused by the variation of the meshing backlash, which is from the floating of all gears at the same time. Finally, we obtained the comprehensive angle meshing error of the two-stage meshing line, established a refined mathematical computational model of 2-stage external 3-split loading sharing coefficient in consideration of displacement compatibility, got the regular curves of the load sharing coefficient and load sharing characteristic curve of full floating multiple-split and multiple-stage system, and took the variation law of the floating track and the floating quantity of the center wheel. These provide a scientific theory to determine the load sharing coefficient, reasonable load distribution, and control tolerances in aviation design and manufacturing.

  12. Lateral restorable characteristics of the high-T{sub c} superconducting maglev vehicle above the permanent magnet guideway

    Energy Technology Data Exchange (ETDEWEB)

    Ma, G.T., E-mail: guangtma@gmail.co [Applied Superconductivity Laboratory, Southwest Jiaotong University, Mail Stop 152, Chengdu, Sichuan 610031 (China); Wang, J.S., E-mail: asclab@asclab.c [Applied Superconductivity Laboratory, Southwest Jiaotong University, Mail Stop 152, Chengdu, Sichuan 610031 (China); Lin, Q.X.; Liu, M.X.; Deng, Z.G.; Li, X.C.; Liu, H.F.; Zheng, J.; Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Mail Stop 152, Chengdu, Sichuan 610031 (China)

    2009-11-01

    The lateral restorable characteristics of a translational symmetry high-T{sub c} superconducting maglev system are investigated by measuring its resonant frequency (f{sub RF}) after a lateral displacement. The difference between whether this lateral displacement is restorable, meaning elastic or inelastic, is determined by whether or not the maglev body returns to its original position after a lateral displacement. The maximum restorable lateral displacement (delta{sub MRLD}) is determined by the sudden change of the f{sub RF} vs. the maximum lateral displacement (delta{sub MLD}) curve. The f{sub RF} of the high-T{sub c} superconducting maglev system with different field-cooling height (FCH) and working height (WH) was obtained from the frequency domain vibration curve which was measured by a vibration measurement system. The results showed that, the delta{sub MRLD} was reduced when the WH was decreased. The maximum restorable guidance force (F{sub MRGF}) was found to not always increase with the lowering of the WH for the same FCH. The lateral restorable stiffness (k{sub LRS}) was always enhanced with the decrease of the WH. The decrease of the delta{sub MRLD} with the WH is interpreted by the fact that, the tangential field component (DELTAH) across the surface of the high-T{sub c} superconductor (HTSC) is easier to exceed the J{sub c}lambda value (J{sub c} is the critical current density and lambda is the London penetration depth) when the WH is lowered, and this makes the trapped flux lines become more susceptible in escaping its pinning sites.

  13. The State non-contractual liability because of forced displacement of persons (Setting up a line of case law in State council decisions

    Directory of Open Access Journals (Sweden)

    Diego Armando Yáñez Meza

    2013-06-01

    Full Text Available Initially the theory of repairing the damage caused by act or omission attributable to the state as a subject faced the dogma of irresponsibility. This was a paradigm that in the context of the new constitutional law should not be allowed any validity because it is not a case of the exercise of a divine power or Leviathan because of its superiority over the inhabitants, as institutionalist theses of yore held. However, as it will be evident, there is some jurisprudence position that reminds us of those theses concerning the state responsibility because of the case of displaced persons and there are doctrinal realities that pose their attenuated return since the law of non-contractual liability appears as an option which is ill-suited for the victims. Hence the need to determine the pattern of resolution to the legal problem posed by the Administrative Justice in order to identify its characteristics and to establish the road map drawn to repair one of the most flagrant violations of human rights and humanitarian international law.

  14. 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...

  15. Inverse Magnus force in free molecular flow

    Science.gov (United States)

    Herczynski, A.; Weidman, P.

    2003-11-01

    The sidewise force on a spinning sphere translating in a rarified gas is calculated assuming that the flow can be treated as a stream of free molecules. This approach was first introduced by Newton in his investigation of the drag force. While it is not fruitful at subsonic flows in normal conditions, it gives remarkably accurate results at hypersonic speeds. Here it is applied to the high Knudsen number flow over spinning spheres, cylinders, cubes and more generally any spinning parallelepiped. In all cases, the force is in the opposite direction to that of the classical Magnus effect in continuum flow. The simple calculation for a sphere reproduces the isothermal result obtained recently by Borg, et al. (Phys. Fluids, 15, 2003) using Maxwellian distribution functions. For any parallelepiped, including the cube, just like for the sphere and the cylinder, the force is shown to be steady. In each of these, the magnitude of the inverse Magnus force is proprtional to the product of the angular speed, translational speed, and the mas of the gas displaced by the object.

  16. FRAME (Force Review Automation Environment): MATLAB-based AFM data processor.

    Science.gov (United States)

    Partola, Kostyantyn R; Lykotrafitis, George

    2016-05-03

    Data processing of force-displacement curves generated by atomic force microscopes (AFMs) for elastic moduli and unbinding event measurements is very time consuming and susceptible to user error or bias. There is an evident need for consistent, dependable, and easy-to-use AFM data processing software. We have developed an open-source software application, the force review automation environment (or FRAME), that provides users with an intuitive graphical user interface, automating data processing, and tools for expediting manual processing. We did not observe a significant difference between manually processed and automatically processed results from the same data sets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Numerical modelling of forces, stresses and breakages of concrete armour units

    NARCIS (Netherlands)

    Latham, John Paul; Xiang, Jiansheng; Anastasaki, Eleni; Guo, Liwei; Karantzoulis, Nikolaos; Viré, A.C.; Pain, Christopher

    2014-01-01

    Numerical modelling has the potential to probe the complexity of the interacting physics of rubble mound armour systems. Through forward modelling of armour unit packs, stochastic variables such as unit displacement and maximum contact force per unit during an external oscillatory disturbance can

  18. Impact of nonlinear distortion on acoustic radiation force elastography.

    Science.gov (United States)

    Draudt, Andrew B; Cleveland, Robin O

    2011-11-01

    High-intensity focused ultrasound (HIFU) produces an acoustic radiation force that induces tissue displacement, which can be measured by monitoring time shifts in the backscattered signals from interrogation pulses. If the pulse occurs simultaneously with the HIFU, the arrival time of the backscatter will be biased because nonlinearity associated with the HIFU changes the local sound speed. Measurements of the pressure field using 1.1 MHz HIFU and a 7.5 MHz pulse in water exhibited a nonlinearly induced apparent displacement (NIAD) that varied with the HIFU pressure, propagation distance and the timing of the pulse relative to the HIFU. Nonlinear simulations employing the KZK equation predicted NIADs that agreed with measurements. Experiments with chicken breast demonstrated a NIAD with magnitude similar to that expected from the radiation force. Finally it was shown that if two pulses were fired with different phases relative to the HIFU, then upon averaging, the NIAD could be mitigated. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  19. Sideways Force Produced During Disruptions

    Science.gov (United States)

    Strauss, H. R.; Paccagnella, R.; Breslau, J.; Jardin, S.; Sugiyama, L.

    2012-10-01

    We extend previous studies [1] of vertical displacement events (VDE) which can produce disruptions. The emphasis is on the non axisymmetric ``sideways'' wall force Fx. Simulations are performed using the M3D [2] code. A VDE expels magnetic flux through the resistive wall until the last closed flux surface has q VDE is presented. The wall force depends strongly on γτw, where γ is the mode growth rate and τw is the wall resistive penetration time. The force Fx is largest when γτw is a constant of order unity, which depends on the initial conditions. For large values of γτw, the wall force asymptotes to a relatively smaller value, well below the critical value ITER is designed to withstand. The principle of disruption mitigation by massive gas injection is to cause a disruption with large γτw. [4pt] [1] H. R. Strauss, R. Paccagnella, and J. Breslau,Phys. Plasmas 17, 082505 (2010) [2] W. Park, E.V. Belova, G.Y. Fu, X. Tang, H.R. Strauss, L.E. Sugiyama, Phys. Plasmas 6, 1796 (1999).

  20. Sensitivity to feature displacement in familiar and unfamiliar faces: beyond the internal/external feature distinction.

    Science.gov (United States)

    Brooks, Kevin R; Kemp, Richard I

    2007-01-01

    Previous studies of face recognition and of face matching have shown a general improvement for the processing of internal features as a face becomes more familiar to the participant. In this study, we used a psychophysical two-alternative forced-choice paradigm to investigate thresholds for the detection of a displacement of the eyes, nose, mouth, or ears for familiar and unfamiliar faces. No clear division between internal and external features was observed. Rather, for familiar (compared to unfamiliar) faces participants were more sensitive to displacements of internal features such as the eyes or the nose; yet, for our third internal feature-the mouth no such difference was observed. Despite large displacements, many subjects were unable to perform above chance when stimuli involved shifts in the position of the ears. These results are consistent with the proposal that familiarity effects may be mediated by the construction of a robust representation of a face, although the involvement of attention in the encoding of face stimuli cannot be ruled out. Furthermore, these effects are mediated by information from a spatial configuration of features, rather than by purely feature-based information.

  1. Characterizing Feedbacks Between Environmental Forcing and Sediment Characteristics in Fluvial and Coastal Systems

    Science.gov (United States)

    Feehan, S.; Ruggiero, P.; Hempel, L. A.; Anderson, D. L.; Cohn, N.

    2016-12-01

    Characterizing Feedbacks Between Environmental Forcing and Sediment Characteristics in Fluvial and Coastal Systems American Geophysical Union, 2016 Fall Meeting: San Francisco, CA Authors: Scott Feehan, Peter Ruggiero, Laura Hempel, and Dylan Anderson Linking transport processes and sediment characteristics within different environments along the source to sink continuum provides critical insight into the dominant feedbacks between grain size distributions and morphological evolution. This research is focused on evaluating differences in sediment size distributions across both fluvial and coastal environments in the U.S. Pacific Northwest. The Cascades' high relief is characterized by diverse flow regimes with high peak/flashy flows and sub-threshold flows occurring in relative proximity and one of the most energetic wave climates in the world. Combining analyses of both fluvial and coastal environments provides a broader understanding of the dominant forces driving differences between each system's grain size distributions, sediment transport processes, and resultant evolution. We consider sediment samples taken during a large-scale flume experiment that simulated floods representative of both high/flashy peak flows analogous to runoff dominated rivers and sub-threshold flows, analogous to spring-fed rivers. High discharge flows resulted in narrower grain size distributions while low flows where less skewed. Relative sediment size showed clear dependence on distance from source and the environments' dominant fluid motion. Grain size distributions and sediment transport rates were also quantified in both wave dominated nearshore and aeolian dominated backshore portions of Long Beach Peninsula, Washington during SEDEX2, the Sandbar-aEolian-Dune EXchange Experiment of summer 2016. The distributions showed spatial patterns in mean grain size, skewness, and kurtosis dependent on the dominant sediment transport process. The feedback between these grain size

  2. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  3. Frictional characteristics of erythrocytes on coated glass plates subject to inclined centrifugal forces.

    Science.gov (United States)

    Kandori, Takashi; Hayase, Toshiyuki; Inoue, Kousuke; Funamoto, Kenichi; Takeno, Takanori; Ohta, Makoto; Takeda, Motohiro; Shirai, Atsushi

    2008-10-01

    In recent years a diamond-like carbon (DLC) film and a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer have attracted attention as coating materials for implantable artificial organs or devices. When these materials are coated on vascular devices, compatibility to blood is an important problem. The present paper focuses on friction characteristics of erythrocytes to these coating materials in a medium. With an inclined centrifuge microscope developed by the authors, observation was made for erythrocytes moving on flat glass plates with and without coating in a medium of plasma or saline under the effect of inclined centrifugal force. Friction characteristics of erythrocytes with respect to these coating materials were then measured and compared to each other to characterize DLC and MPC as coating materials. The friction characteristics of erythrocytes in plasma using the DLC-coated and noncoated glass plates are similar, changing approximately proportional to the 0.5th power of the cell velocity. The cells stick to these plates in saline as well, implying the influence of plasma protein. The results using the MPC-coated plate in plasma are similar to those of the other plates for large cell velocities, but deviate from the other results with decreased cell velocity. The results change nearly proportional to the 0.75th power of the cell velocity in the range of small velocities. The results for the MPC-coated plate in saline are similar to that in plasma but somewhat smaller, implying that the friction characteristics for the MPC-coated plate are essentially independent of plasma protein.

  4. Effects of Energy Deposition Characteristics on Localised Forced Ignition of Homogeneous Mixtures

    Directory of Open Access Journals (Sweden)

    Dipal Patel

    2015-06-01

    Full Text Available The effects of the characteristic width of the energy deposition profile and the duration of energy deposition by the ignitor on localised forced ignition of stoichiometric and fuel-lean homogeneous mixtures have been analysed using simplified chemistry three-dimensional compressible Direct Numerical Simulation (DNS for different values of root-mean-square turbulent velocity fluctuation. The localised forced ignition is modelled using a source term in the energy transport equation, which deposits energy in a Gaussian manner from the centre of the ignitor over a stipulated period of time. It has been shown that the width of ignition energy deposition and the duration over which ignition energy is deposited have significant influences on the success of ignition and subsequent flame propagation. An increase in the width of ignition energy deposition (duration of energy deposition for a given amount of ignition energy has been found to have a detrimental effect on the ignition event, which may ultimately lead to misfire. Moreover, an increase in u′ gives rise to augmented heat transfer rate from the hot gas kernel, which in turn leads to a reduction in the extent of overall burning for both stoichiometric and fuel-lean homogeneous mixtures but the detrimental effects of high values of u′ on localised ignition are particularly prevalent for fuel-lean mixtures.

  5. Displaced epithelium after liposuction for gynecomastia.

    Science.gov (United States)

    McLaughlin, Cristina S; Petrey, Chris; Grant, Shawn; Ransdell, Jill S; Reynolds, Carol

    2011-08-01

    The authors describe the case of a 36-year-old man with gynecomastia who was previously treated with liposuction of the breast for cosmetic purposes. Histologic examination of a subsequent excisional biopsy revealed nests of displaced epithelial cells in adipose tissue. Epithelial cell displacement is a well-known risk of core needle biopsies and fine-needle aspirations of breast lesions. However, to the authors' knowledge, epithelial displacement in gynecomastia after liposuction, mimicking invasive ductal carcinoma, has not previously been reported.

  6. 3D characterization of the forces in optical traps based on counter-propagation beams shaped by a spatial light modulator

    DEFF Research Database (Denmark)

    Kristensen, M. V.; Lindballe, T.; Kylling, A.

    2010-01-01

    An experimental characterization of the 3D forces, acting on a trapped polystyrene bead in a counter-propagating beam geometry, is reported. Using a single optical trap with a large working distance (in the BioPhotonics Workstation), we simultaneously measure the transverse and longitudinal...... trapping force constants. Two different methods were used: The Drag force method and the Equipartition method. We show that the counterpropagating beams traps are simple harmonic for small displacements. The force constants reveal a transverse asymmetry as - = 9.7 pN/µm and + = 11.3 pN/µm (at a total laser...... power of 2x35 mW) for displacements in opposite directions. The Equipartition method is limited by mechanical noise and is shown to be applicable only when the total laser power in a single 10 µm counter-propagating trap is below 2x20 mW....

  7. Relation between knee extensors' strength, postural stability and variability of centre of pressure displacement during gait in adult women

    Directory of Open Access Journals (Sweden)

    Eliza C. de Souza

    2017-03-01

    Full Text Available Background: It has been shown that variability of walking is related to fall risk similarly as postural control and muscle strength. Joint potential of this group of variables for fall risk assessment is promising, however research interested in relations between them is lacking. Objective: The aim of this study was to investigate the relation between knee extensors' strength, centre of pressure (COP velocity during one-leg stance and variability of COP displacement during various phases of gait cycle in middle-age women. Methods: A single group of 40 healthy women (age 56 ± 4.2 years took part in the study. For assessment of knee extensors' strength (peak torque and average work during concentric and eccentric contractions an isokinetic dynamometer was used. Mean velocity of COP during one-leg stance in anterior-posterior (AP and medial-lateral (ML directions was assessed on a force plate on a rigid surface with eyes open (two 30 s trials. Variability of COP displacement was assessed for loading response, midstance, terminal stance and preswing gait cycle phases (determined by vertical ground reaction force in AP and ML directions. It was measured by two force plates positioned in the middle of an 8 m walkway (5 trials at a self-selected speed. For statistical analysis of relationships between variables Pearson correlation was applied. Results: Our results showed significant correlations between eccentric peak torque and COP velocity in AP direction during one-leg stance, eccentric and concentric peak torque and COP variability during loading response in both ML and AP directions and during terminal stance in AP direction. Conclusion: Loading response and terminal stance seems to be more related to knee extensors' strength. Variables derived from postural stability assessment during one-leg stance are independent from variables derived from assessment of COP displacement variability during walking.

  8. 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.

  9. Race to Displace: A Game to Model the Effects of Invasive Species on Plant Communities

    Science.gov (United States)

    Hopwood, Jennifer L.; Flowers, Susan K.; Seidler, Katie J.; Hopwood, Erica L.

    2013-01-01

    Invasive species are a substantial threat to biodiversity. Educating students about invasive species introduces fundamental concepts in biology, ecology, and environmental science. In the Race to Displace game, students assume the characteristics of select native or introduced plants and experience first hand the influences of species interactions…

  10. The characteristics of a pneumatic muscle

    Directory of Open Access Journals (Sweden)

    Pietrala Dawid

    2017-01-01

    Full Text Available The article presents static and dynamic characteristics of pneumatic muscles. It presents the structure of the laboratory stand used to test pneumatic muscles. It discusses the methodology for determination of static and dynamic characteristics. The paper also illustrates characteristics showing the relationship of pneumatic muscles length and operating pressure, at a constant loading force (isotonic characteristics. It presents characteristics showing the relationship of pneumatic muscles shortening and values of loading forces, at a constant operational pressure (isobaric characteristics. It also shows the dependence of force generated by the muscle on the operating pressure, at a constant value of pneumatic muscles shortening (isometric characteristics. The paper also presents dynamic characteristics of a pneumatic muscle showing the response of an object to a gradual change in the operating pressure, at a constant loading force acting on the pneumatic muscle.

  11. The characteristics of a pneumatic muscle

    Science.gov (United States)

    Pietrala, Dawid

    The article presents static and dynamic characteristics of pneumatic muscles. It presents the structure of the laboratory stand used to test pneumatic muscles. It discusses the methodology for determination of static and dynamic characteristics. The paper also illustrates characteristics showing the relationship of pneumatic muscles length and operating pressure, at a constant loading force (isotonic characteristics). It presents characteristics showing the relationship of pneumatic muscles shortening and values of loading forces, at a constant operational pressure (isobaric characteristics). It also shows the dependence of force generated by the muscle on the operating pressure, at a constant value of pneumatic muscles shortening (isometric characteristics). The paper also presents dynamic characteristics of a pneumatic muscle showing the response of an object to a gradual change in the operating pressure, at a constant loading force acting on the pneumatic muscle.

  12. Design, Fabrication, and Characteristics Experiment of a Large LVDT Sensor for of Bottom Mounted CRDM

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

    The stepping motor directly drives the ball screw, and the nut of the ball screw makes the electromagnet move up and down along the guide tube. At this time the higher force of an electromagnet will greatly result in less position fluctuation of the armature for a given variation of loadings. The magnetic rigidity represents one of the most important characteristics of the electromagnet. For this reason, it is necessary to measure control rod position including sagging rate due to loadings exactly. Therefore, KAERI has developed electromagnet rigidity measuring sensor using LVDT. This paper presents the case numerical and experimental research of prototyping a large LVDT sensor for BMCRDM. The FEM and experimental results for optimized large LVDT shows good linearity agreement of displacement vs. induced currents between 0[mm] and ±22[mm] intervals. The experimental result has shorter linearity interval than that of FEM result due to 100[mm] core length using experimental test. The developed FE model and analysis procedure could be useful tools for predicting the linearity of displacement of a large LVDT.

  13. Prolonged displacement may compromise resilience in Eritrean mothers.

    Science.gov (United States)

    Almedom, Astier; Tesfamichael, Berhe; Mohammed, Zein; Mascie-Taylor, Nick; Muller, Jocelyn; Alemu, Zemui

    2005-12-01

    to assess the impact of prolonged displacement on the resilience of Eritrean mothers. 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. Displaced women's SOC scores were significantly less than those of the non-displaced: Mean = 54.84; SD = 6.48 in internally displaced person (IDP) camps, compared to non-displaced urban and rural/pastoralist: Mean = 48. 94, SD = 11.99; t = 3.831, p urban (non-displaced). Rural but traditionally mobile (pastoralist or transhumant) communities scored more or less the same as the urban non-displaced--i.e., significantly higher than those in IDP camps (p urban and pastoralist/transhumant groups were similar, while women in IDP camps were lower scoring--RR = .268, p < .001. The implications of these findings for health policy are critical. It is incumbent on the international health institutions including the World Health Organization and regional as well as local players to address the plight of internally displaced women, their families and communities in Eritrea and other places of dire conditions such as, for example Darfur in the Sudan.

  14. Using indirect methods to understand the impact of forced migration on long-term under-five mortality.

    Science.gov (United States)

    Singh, Kavita; Karunakara, Unni; Burnham, Gilbert; Hill, Kenneth

    2005-11-01

    Despite the large numbers of displaced persons and the often-lengthy periods of displacement, little is known about the impact of forced migration on long-term under-five mortality. This paper looks at the Brass Method (and adaptations of this method) and the Preceding Birth Technique in combination with a classification of women by their migration and reproductive histories, in order to study the impact of forced migration on under-five mortality. Data came from the Demography of Forced Migration Project, a study on mortality, fertility and violence in the refugee and host populations of Arua District, Uganda and Yei River District, Sudan. Results indicate that women who did not migrate in a situation of conflict and women who repatriated before the age of 15, had children with the highest under-five mortality rates compared with women who were currently refugees and women who repatriated after the age of 15.

  15. Unsteady force estimation using a Lagrangian drift-volume approach

    Science.gov (United States)

    McPhaden, Cameron J.; Rival, David E.

    2018-04-01

    A novel Lagrangian force estimation technique for unsteady fluid flows has been developed, using the concept of a Darwinian drift volume to measure unsteady forces on accelerating bodies. The construct of added mass in viscous flows, calculated from a series of drift volumes, is used to calculate the reaction force on an accelerating circular flat plate, containing highly-separated, vortical flow. The net displacement of fluid contained within the drift volumes is, through Darwin's drift-volume added-mass proposition, equal to the added mass of the plate and provides the reaction force of the fluid on the body. The resultant unsteady force estimates from the proposed technique are shown to align with the measured drag force associated with a rapid acceleration. The critical aspects of understanding unsteady flows, relating to peak and time-resolved forces, often lie within the acceleration phase of the motions, which are well-captured by the drift-volume approach. Therefore, this Lagrangian added-mass estimation technique opens the door to fluid-dynamic analyses in areas that, until now, were inaccessible by conventional means.

  16. Design Principles for Rapid Prototyping Forces Sensors using 3D Printing.

    Science.gov (United States)

    Kesner, Samuel B; Howe, Robert D

    2011-07-21

    Force sensors provide critical information for robot manipulators, manufacturing processes, and haptic interfaces. Commercial force sensors, however, are generally not adapted to specific system requirements, resulting in sensors with excess size, cost, and fragility. To overcome these issues, 3D printers can be used to create components for the quick and inexpensive development of force sensors. Limitations of this rapid prototyping technology, however, require specialized design principles. In this paper, we discuss techniques for rapidly developing simple force sensors, including selecting and attaching metal flexures, using inexpensive and simple displacement transducers, and 3D printing features to aid in assembly. These design methods are illustrated through the design and fabrication of a miniature force sensor for the tip of a robotic catheter system. The resulting force sensor prototype can measure forces with an accuracy of as low as 2% of the 10 N measurement range.

  17. A new image correction method for live cell atomic force microscopy

    International Nuclear Information System (INIS)

    Shen, Y; Sun, J L; Zhang, A; Hu, J; Xu, L X

    2007-01-01

    During live cell imaging via atomic force microscopy (AFM), the interactions between the AFM probe and the membrane yield distorted cell images. In this work, an image correction method was developed based on the force-distance curve and the modified Hertzian model. The normal loading and lateral forces exerted on the cell membrane by the AFM tip were both accounted for during the scanning. Two assumptions were made in modelling based on the experimental measurements: (1) the lateral force on the endothelial cells was linear to the height; (2) the cell membrane Young's modulus could be derived from the displacement measurement of a normal force curve. Results have shown that the model could be used to recover up to 30% of the actual cell height depending on the loading force. The accuracy of the model was also investigated with respect to the loading force and mechanical property of the cell membrane

  18. Stress distribution and displacement of abutment of middle implant-natural teeth fixed bridge under different loading

    International Nuclear Information System (INIS)

    Chen Erjun; Zhou Yanmin; Ma Chenchun; Cong Zhiqiang; Jiang Yonghua

    2004-01-01

    Objective: To study stress distribution and displacement of abutment of middle implant-natural teeth fixed bridge under different loading. Methods: The stress distribution and displacement of abutment were studied and analyzed by means of three-dimensional finite element when different loading was applied. Results: The biggest stress of middle implant was 4-5 times as big as that of natural teeth. Under concentrated vertical loading, the biggest stress of implant was about 2 times higher than that under dispersed vertical loading. There was no significant difference of biggest stress on the implant between concentrated oblique loading and dispersed oblique loading. The biggest stress of implant under oblique loading was 3 times as big as that under dispersed vertical loading. The biggest stress of natural teeth under dispersed loading was lower than that under concentrated loading. The maximum displacement of implant in occlusal-gum direction was great lower than that of natural teeth. Both in buccal-lingual direction and medial-distal direction, the displacement of implant were about equal to that of natural teeth. Conclusion: The oblique loading is the main force to destroy the middle implant-natural teeth fixed bridge. The lean of cusp should be reduced. The abnormally high occlusal points should be deleted. The bite points should be well distributed. The fixed bridge is feasible. (authors)

  19. Unsupervised DInSAR processing chain for multi-scale displacement analysis

    Science.gov (United States)

    Casu, Francesco; Manunta, Michele

    2016-04-01

    Earth Observation techniques can be very helpful for the estimation of several sources of ground deformation due to their characteristics of large spatial coverage, high resolution and cost effectiveness. In this scenario, Differential Synthetic Aperture Radar Interferometry (DInSAR) is one of the most effective methodologies for its capability to generate spatially dense deformation maps at both global and local spatial scale, with centimeter to millimeter accuracy. DInSAR exploits the phase difference (interferogram) between SAR image pairs relevant to acquisitions gathered at different times, but with the same illumination geometry and from sufficiently close flight tracks, whose separation is typically referred to as baseline. Among several, the SBAS algorithm is one of the most used DInSAR approaches and it is aimed at generating displacement time series at a multi-scale level by exploiting a set of small baseline interferograms. SBAS, and generally DInSAR, has taken benefit from the large availability of spaceborne SAR data collected along years by several satellite systems, with particular regard to the European ERS and ENVISAT sensors, which have acquired SAR images worldwide during approximately 20 years. Moreover, since 2014 the new generation of Copernicus Sentinel satellites has started to acquire data with a short revisit time (12 days) and a global coverage policy, thus flooding the scientific EO community with an unprecedent amount of data. To efficiently manage such amount of data, proper processing facilities (as those coming from the emerging Cloud Computing technologies) have to be used, as well as novel algorithms aimed at their efficient exploitation have to be developed. In this work we present a set of results achieved by exploiting a recently proposed implementation of the SBAS algorithm, namely Parallel-SBAS (P-SBAS), which allows us to effectively process, in an unsupervised way and in a limited time frame, a huge number of SAR images

  20. Influences of load characteristics on impaired control of grip forces in patients with cerebellar damage.

    Science.gov (United States)

    Brandauer, B; Timmann, D; Häusler, A; Hermsdörfer, J

    2010-02-01

    Various studies showed a clear impairment of cerebellar patients to modulate grip force in anticipation of the loads resulting from movements with a grasped object. This failure corroborated the theory of internal feedforward models in the cerebellum. Cerebellar damage also impairs the coordination of multiple-joint movements and this has been related to deficient prediction and compensation of movement-induced torques. To study the effects of disturbed torque control on feedforward grip-force control, two self-generated load conditions with different demands on torque control-one with movement-induced and the other with isometrically generated load changes-were directly compared in patients with cerebellar degeneration. Furthermore the cerebellum is thought to be more involved in grip-force adjustment to self-generated loads than to externally generated loads. Consequently, an additional condition with externally generated loads was introduced to further test this hypothesis. Analysis of 23 patients with degenerative cerebellar damage revealed clear impairments in predictive feedforward mechanisms in the control of both self-generated load types. Besides feedforward control, the cerebellar damage also affected more reactive responses when the externally generated load destabilized the grip, although this impairment may vary with the type of load as suggested by control experiments. The present findings provide further support that the cerebellum plays a major role in predictive control mechanisms. However, this impact of the cerebellum does not strongly depend on the nature of the load and the specific internal forward model. Contributions to reactive (grip force) control are not negligible, but seem to be dependent on the physical characteristics of an externally generated load.

  1. Displaced and non-displaced Colombian children's evaluations of moral transgressions, retaliation, and reconciliation

    Science.gov (United States)

    Ardila-Rey, Alicia; Killen, Melanie; Brenick, Alaina

    2015-01-01

    In order to assess the effects of displacement and exposure to violence on children's moral reasoning, Colombian children exposed to minimal violence (non-displaced or low-risk) (N = 99) and to extreme violence (displaced or high-risk) (N = 94), evenly divided by gender, at 6-, 9-, and 12 - years of age, were interviewed regarding their evaluation of peer-oriented moral transgressions (hitting and not sharing toys). The vast majority of children evaluated moral transgressions as wrong. Group and age differences were revealed, however, regarding provocation and retaliation. Children who were exposed to violence, in contrast to those with minimum exposure, judged it more legitimate to inflict harm or deny resources when provoked and judged it more okay to retaliate for reasons of retribution. Surprisingly, and somewhat hopefully, all children viewed reconciliation as feasible. The results are informative regarding theories of morality, culture, and the effects of violence on children's social development. PMID:25722543

  2. Displacement of location in illusory line motion.

    Science.gov (United States)

    Hubbard, Timothy L; Ruppel, Susan E

    2013-05-01

    Six experiments examined displacement in memory for the location of the line in illusory line motion (ILM; appearance or disappearance of a stationary cue is followed by appearance of a stationary line that is presented all at once, but the stationary line is perceived to "unfold" or "be drawn" from the end closest to the cue to the end most distant from the cue). If ILM was induced by having a single cue appear, then memory for the location of the line was displaced toward the cue, and displacement was larger if the line was closer to the cue. If ILM was induced by having one of two previously visible cues vanish, then memory for the location of the line was displaced away from the cue that vanished. In general, the magnitude of displacement increased and then decreased as retention interval increased from 50 to 250 ms and from 250 to 450 ms, respectively. Displacement of the line (a) is consistent with a combination of a spatial averaging of the locations of the cue and the line with a relatively weaker dynamic in the direction of illusory motion, (b) might be implemented in a spreading activation network similar to networks previously suggested to implement displacement resulting from implied or apparent motion, and (c) provides constraints and challenges for theories of ILM.

  3. Variable displacement alpha-type Stirling engine

    Science.gov (United States)

    Homutescu, V. M.; Bălănescu, D. T.; Panaite, C. E.; Atanasiu, M. V.

    2016-08-01

    The basic design and construction of an alpha-type Stirling engine with on load variable displacement is presented. The variable displacement is obtained through a planar quadrilateral linkage with one on load movable ground link. The physico-mathematical model used for analyzing the variable displacement alpha-type Stirling engine behavior is an isothermal model that takes into account the real movement of the pistons. Performances and power adjustment capabilities of such alpha-type Stirling engine are calculated and analyzed. An exemplification through the use of the numerical simulation was performed in this regard.

  4. Neutron displacement damage cross sections for SiC

    International Nuclear Information System (INIS)

    Huang Hanchen; Ghoniem, N.

    1993-01-01

    Calculations of neutron displacement damage cross sections for SiC are presented. We use Biersack and Haggmark's empirical formula in constructing the electronic stopping power, which combines Lindhard's model at low PKA energies and Bethe-Bloch's model at high PKA energies. The electronic stopping power for polyatomic materials is computed on the basis of Bragg's Additivity Rule. A continuous form of the inverse power law potential is used for nuclear scattering. Coupled integro-differential equations for the number of displaced atoms j, caused by PKA i, are then derived. The procedure outlined above gives partial displacement cross sections, displacement cross sections for each specie of the lattice, and for each PKA type. The corresponding damage rates for several fusion and fission neutron spectra are calculated. The stoichiometry of the irradiated material is investigated by finding the ratio of displacements among various atomic species. The role of each specie in displacing atoms is also investigated by calculating the fraction of displacements caused by each PKA type. The study shows that neutron displacement damage rates of SiC in typical magnetic fusion reactor first walls will be ∝10-15 dpa MW -1 m 2 ; in typical lead-protected inertial confinement fusion reactor first walls they will be ∝15-20 dpa MW -1 m 2 . For fission spectra, we find that the neutron displacement damage rate of SiC is ∝74 dpa per 10 27 n/m 2 in FFTF, ∝39 dpa per 10 27 n/m 2 in HFIR, and 25 dpa per 10 27 n/m 2 in NRU. Approximately 80% of displacement atoms are shown to be of the carbon-type. (orig.)

  5. Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study.

    Science.gov (United States)

    Chen, Pengbo; Lu, Hua; Shen, Hao; Wang, Wei; Ni, Binbin; Chen, Jishizhan

    2017-02-23

    Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

  6. Energy dissipation in multifrequency atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Valentina Pukhova

    2014-04-01

    Full Text Available The instantaneous displacement, velocity and acceleration of a cantilever tip impacting onto a graphite surface are reconstructed. The total dissipated energy and the dissipated energy per cycle of each excited flexural mode during the tip interaction is retrieved. The tip dynamics evolution is studied by wavelet analysis techniques that have general relevance for multi-mode atomic force microscopy, in a regime where few cantilever oscillation cycles characterize the tip–sample interaction.

  7. Asymmetric SOL Current in Vertically Displaced Plasma

    Science.gov (United States)

    Cabrera, J. D.; Navratil, G. A.; Hanson, J. M.

    2017-10-01

    Experiments at the DIII-D tokamak demonstrate a non-monotonic relationship between measured scrape-off layer (SOL) currents and vertical displacement event (VDE) rates with SOL currents becoming largely n=1 dominant as plasma is displaced by the plasma control system (PCS) at faster rates. The DIII-D PCS is used to displace the magnetic axis 10x slower than the intrinsic growth time of similar instabilities in lower single-null plasmas. Low order (n VDE instabilities observed when vertical control is disabled. Previous inquiry shows VDE asymmetry characterized by SOL current fraction and geometric parameters of tokamak plasmas. We note that, of plasmas displaced by the PCS, short displacement time scales near the limit of the PCS temporal control appear to result in larger n=1/n=2 asymmetries. Work supported under USDOE Cooperative Agreement DE-FC02-04ER54698 and DE-FG02-04ER54761.

  8. Vertical, radial and drag force analysis of superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Cansiz, Ahmet

    2009-01-01

    The behavior of the force between a permanent magnet (PM) and a high temperature superconductor (HTS) was tested with the frozen-image model based on flux pinning. It was found that the associated dipole moment assumptions of the method of the frozen image underestimate the force somewhat; thus a quadrupole moment analysis is proposed. The radial and drag forces associated with the rotation of the PM levitated above the HTS were measured by using a force transducer and by means of a cantilevered beam technique. The radial force was found not to be dependent on the radial direction, and the least radial force was found to be periodic with an angular displacement during the slow rotation of the PM relative to the HTS. The periodicity behavior of the force is attributed to the geometric eccentricity from the magnetization distribution of the PM and HTS. The drag force associated with the torsional stiffness of the levitated PM during the low and high rotational speeds was incorporated with the data from the literature.

  9. Dynamics of an inline tube array in steam-water flow. Part 2: Unsteady fluid forces

    International Nuclear Information System (INIS)

    Mureithi, N.W.; Nakamura, T.; Hirota, K.; Murata, M.; Utsumi, S.

    1996-01-01

    The existence of fluidelastic instability in two-phase flow has been confirmed by a number of investigators to date. In essentially homogeneous two-phase flow, e.g., bubbly flow, it appears that the mechanisms underlying fluidelastic instability and the instability phenomenon are the same as those observed in single phase flow. The more general case of non-homogeneous two-phase flow, e.g., slug flow, is less amenable to straight forward interpretation by direct comparison with single phase flow mechanisms. In this paper, experimental results of unsteady fluid force measurement are reported. Important deviations of the measured fluid force from their single phase flow counterparts were uncovered. Most importantly, the resulting force coefficients are not simple functions of the reduced velocity U/fD, as is the case for single phase flow. Test results at 0.5 MPa challenge the basic assumption of the existence of a time invariant linear transfer function between tube displacement and the resulting fluid forces. Time-frequency analysis using Wignerville transforms shows that the phase difference between tube displacement and the fluid force (an indicator of stabilizing or destabilizing fluid effects) undergoes significant variation under what may be considered steady flow conditions. This variation may explain the previously reported phenomenon of intermittent fluidelastic instability in two-phase flows

  10. Error Correction of Radial Displacement in Grinding Machine Tool Spindle by Optimizing Shape and Bearing Tuning

    OpenAIRE

    Khairul Jauhari; Achmad Widodo; Ismoyo Haryanto

    2015-01-01

    In this article, the radial displacement error correction capability of a high precision spindle grinding caused by unbalance force was investigated. The spindle shaft is considered as a flexible rotor mounted on two sets of angular contact ball bearing. Finite element methods (FEM) have been adopted for obtaining the equation of motion of the spindle. In this paper, firstly, natural frequencies, critical frequencies, and amplitude of the unbalance response caused by resi...

  11. Asymptotic behavior of the mean square displacement of the Brownian parametric oscillator near the singular point

    International Nuclear Information System (INIS)

    Tashiro, Tohru

    2009-01-01

    A parametric oscillator with damping driven by white noise is studied. The mean square displacement (MSD) in the long-time limit is derived analytically for the case that the static force vanishes, which was not treated in the past work (Tashiro and Morita 2007 Physica A 377 401). The formula is asymptotic but is applicable to a general periodic function. On the basis of this formula, some periodic functions reducing MSD remarkably are proposed

  12. 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...

  13. Displacement of a dental implant into the maxillary sinus after internal sinus floor elevation: report of a case and review of literature.

    Science.gov (United States)

    Ding, Xiaojun; Wang, Qing; Guo, Xuehua; Yu, Youcheng

    2015-01-01

    Dental implant placement in the posterior maxilla may be complicated by implant migration into the maxillary sinus. To report the clinical and radiological characteristics of a patient who experienced dental implant displacement into the maxillary sinus following sinus floor elevation, and to compare our findings with those of other published reports of the displacement of dental implants. Implant placement and maxillary sinus elevation were performed simultaneously. The location of the displaced implant was monitored for 8 years, until the ectopic implant was surgically removed using the lateral window approach. The contributing factors, treatment modality, and clinical outcome for our patient were compared with those of patients reported in the literature. The clinical characteristics of our case were similar to those of patients with displaced implants who were also asymptomatic for long periods. The clinical outcome of our case was consistent with that of patients who underwent similar surgeries. Transnasal endoscopic removal of an ectopic implant may be suitable in cases in which the ectopic implant is accessible. Transoral direct approaches are adequate in most cases in which endoscopic approaches may be confounded. The bony-window transoral technique may allow the removal of large implants.

  14. Lagrangian statistics in weakly forced two-dimensional turbulence.

    Science.gov (United States)

    Rivera, Michael K; Ecke, Robert E

    2016-01-01

    Measurements of Lagrangian single-point and multiple-point statistics in a quasi-two-dimensional stratified layer system are reported. The system consists of a layer of salt water over an immiscible layer of Fluorinert and is forced electromagnetically so that mean-squared vorticity is injected at a well-defined spatial scale ri. Simultaneous cascades develop in which enstrophy flows predominately to small scales whereas energy cascades, on average, to larger scales. Lagrangian correlations and one- and two-point displacements are measured for random initial conditions and for initial positions within topological centers and saddles. Some of the behavior of these quantities can be understood in terms of the trapping characteristics of long-lived centers, the slow motion near strong saddles, and the rapid fluctuations outside of either centers or saddles. We also present statistics of Lagrangian velocity fluctuations using energy spectra in frequency space and structure functions in real space. We compare with complementary Eulerian velocity statistics. We find that simultaneous inverse energy and enstrophy ranges present in spectra are not directly echoed in real-space moments of velocity difference. Nevertheless, the spectral ranges line up well with features of moment ratios, indicating that although the moments are not exhibiting unambiguous scaling, the behavior of the probability distribution functions is changing over short ranges of length scales. Implications for understanding weakly forced 2D turbulence with simultaneous inverse and direct cascades are discussed.

  15. Pathways linking war and displacement to parenting and child adjustment: A qualitative study with Syrian refugees in Lebanon.

    Science.gov (United States)

    Sim, Amanda; Fazel, Mina; Bowes, Lucy; Gardner, Frances

    2018-03-01

    Forcibly displaced children are at risk of a range of negative outcomes, yet little is known about how to support war-affected caregivers in promoting children's psychosocial resilience. The current study uses qualitative methods to examine the mechanisms underlying the effects of war and displacement on parenting and child adjustment in order to inform intervention development. In April and November 2016, group and individual interviews were conducted with 39 Syrian parents and 15 children in partnership with a humanitarian organization in Lebanon. Interviews were transcribed and analyzed using a grounded theory approach. Results show three interrelated pathways linking daily displacement stressors to various dimensions of parenting: (1) economic hardship prevents parents from meeting their children's basic needs and forces adaptation strategies that impair positive parent-child interactions; (2) parental psychological distress contributes to harsh parenting; and (3) perceptions and experiences of insecurity in the community results in increased parental control. Greater economic resources and social support emerged as potential protective factors for maintaining positive parenting despite exposure to war and displacement-related adversity. Our findings suggest that implementation of policies and programs to remove structural barriers to refugees' physical and economic security can have tangible impacts on parental mental health, parenting quality, and child psychosocial outcomes. Future research priorities include a stronger focus on the effects of war and displacement on family processes, taking into account interactions with the broader social, economic and political context. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Touching force response of the piezoelectric Braille cell.

    Science.gov (United States)

    Smithmaitrie, Pruittikorn; Kanjantoe, Jinda; Tandayya, Pichaya

    2008-11-01

    The objective of this research is to investigate dynamic responses of the piezoelectric Braille cell when it is subjected to both electrical signal and touching force. Physical behavior of the piezoelectric actuator inside the piezoelectric Braille cell is analyzed. The mathematical model of the piezoelectric Braille system is presented. Then, data of visually impaired people using a Braille Note is studied as design information and a reference input for calculation of the piezoelectric Braille response under the touching force. The results show dynamic responses of the piezoelectric Braille cell. The designed piezoelectric bimorph has a settling time of 0.15 second. The relationship between the Braille dot height and applied voltage is linear. The behavior of the piezoelectric Braille dot when it is touched during operation shows that the dot height is decreased as the force increases. The result provides understanding of the piezoelectric Braille cell behavior under both touching force and electrical excitation simultaneously. This is the important issue for the design and development of piezoelectric Braille cells in senses of controlling Braille dot displacement or force-feedback in the future.

  17. 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…

  18. Pulsed laser manipulation of an optically trapped bead: Averaging thermal noise and measuring the pulsed force amplitude

    DEFF Research Database (Denmark)

    Lindballe, Thue Bjerring; Kristensen, Martin V. G.; Keiding, Søren Rud

    2013-01-01

    An experimental strategy for post-eliminating thermal noise on position measurements of optically trapped particles is presented. Using a nanosecond pulsed laser, synchronized to the detection system, to exert a periodic driving force on an optically trapped 10 polystyrene bead, the laser pulse-bead...... interaction is repeated hundreds of times. Traces with the bead position following the prompt displacement from equilibrium, induced by each laser pulse, are averaged and reveal the underlying deterministic motion of the bead, which is not visible in a single trace due to thermal noise. The motion of the bead...... is analyzed from the direct time-dependent position measurements and from the power spectrum. The results show that the bead is on average displaced 208 nm from the trap center and exposed to a force amplitude of 71 nanoNewton, more than five orders of magnitude larger than the trapping forces. Our...

  19. A new image correction method for live cell atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y; Sun, J L; Zhang, A; Hu, J; Xu, L X [College of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030 (China)

    2007-04-21

    During live cell imaging via atomic force microscopy (AFM), the interactions between the AFM probe and the membrane yield distorted cell images. In this work, an image correction method was developed based on the force-distance curve and the modified Hertzian model. The normal loading and lateral forces exerted on the cell membrane by the AFM tip were both accounted for during the scanning. Two assumptions were made in modelling based on the experimental measurements: (1) the lateral force on the endothelial cells was linear to the height; (2) the cell membrane Young's modulus could be derived from the displacement measurement of a normal force curve. Results have shown that the model could be used to recover up to 30% of the actual cell height depending on the loading force. The accuracy of the model was also investigated with respect to the loading force and mechanical property of the cell membrane.

  20. Preliminary structural assessment of DEMO vacuum vessel against a vertical displacement event

    International Nuclear Information System (INIS)

    Mozzillo, Rocco; Tarallo, Andrea; Marzullo, Domenico; Bachmann, Christian; Di Gironimo, Giuseppe; Mazzone, Giuseppe

    2016-01-01

    Highlights: • The paper focuses on a preliminary structural analysis of the current concept design of DEMO vacuum vessel. • The Vacuum Vessel was checked against the VDE in combinations with the weight force of all components that the vessel shall bear. • Different configurations for the vacuum vessel supports are considered, showing that the best solution is VV supported at the lower port. • The analyses evaluated the “P damage” according to RCC-MRx code. - Abstract: This paper focuses on a preliminary structural analysis of the current concept design of DEMO vacuum vessel (VV). The VV structure is checked against a vertical load due to a Vertical Displacement Event in combination with the weight force of all components that the main vessel shall bear. Different configurations for the supports are considered. Results show that the greatest safety margins are reached when the tokamak is supported through the lower ports rather than the equatorial ports, though all analyzed configurations are compliant with RCC-MRx design rules.

  1. Preliminary structural assessment of DEMO vacuum vessel against a vertical displacement event

    Energy Technology Data Exchange (ETDEWEB)

    Mozzillo, Rocco, E-mail: rocco.mozzillo@unina.it [CREATE, University of Naples Federico II, DII, P.le Tecchio 80, 80125, Naples (Italy); Tarallo, Andrea; Marzullo, Domenico [CREATE, University of Naples Federico II, DII, P.le Tecchio 80, 80125, Naples (Italy); Bachmann, Christian [EUROfusion PMU, Boltzmannstraße 2, 85748 Garching (Germany); Di Gironimo, Giuseppe [CREATE, University of Naples Federico II, DII, P.le Tecchio 80, 80125, Naples (Italy); Mazzone, Giuseppe [Unità Tecnica Fusione - ENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy)

    2016-11-15

    Highlights: • The paper focuses on a preliminary structural analysis of the current concept design of DEMO vacuum vessel. • The Vacuum Vessel was checked against the VDE in combinations with the weight force of all components that the vessel shall bear. • Different configurations for the vacuum vessel supports are considered, showing that the best solution is VV supported at the lower port. • The analyses evaluated the “P damage” according to RCC-MRx code. - Abstract: This paper focuses on a preliminary structural analysis of the current concept design of DEMO vacuum vessel (VV). The VV structure is checked against a vertical load due to a Vertical Displacement Event in combination with the weight force of all components that the main vessel shall bear. Different configurations for the supports are considered. Results show that the greatest safety margins are reached when the tokamak is supported through the lower ports rather than the equatorial ports, though all analyzed configurations are compliant with RCC-MRx design rules.

  2. Validation of the FEA of a deep drawing process with additional force transmission

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Grbic, N.; Vucetic, M.

    2017-10-01

    In order to meet requirements by automotive industry like decreasing the CO2 emissions, which reflects in reducing vehicles mass in the car body, the chassis and the powertrain, the continuous innovation and further development of existing production processes are required. In sheet metal forming processes the process limits and components characteristics are defined through the process specific loads. While exceeding the load limits, a failure in the material occurs, which can be avoided by additional force transmission activated in the deep drawing process before the process limit is achieved. This contribution deals with experimental investigations of a forming process with additional force transmission regarding the extension of the process limits. Based on FEA a tool system is designed and developed by IFUM. For this purpose, the steel material HCT600 is analyzed numerically. Within the experimental investigations, the deep drawing processes, with and without the additional force transmission are carried out. Here, a comparison of the produced rectangle cups is done. Subsequently, the identical deep drawing processes are investigated numerically. Thereby, the values of the punch reaction force and displacement are estimated and compared with experimental results. Thus, the validation of material model is successfully carried out on process scale. For further quantitative verification of the FEA results the experimental determined geometry of the rectangular cup is measured optically with ATOS system of the company GOM mbH and digitally compared with external software Geomagic®QualifyTM. The goal of this paper is the verification of the transferability of the FEA model for a conventional deep drawing process to a deep drawing process with additional force transmission with a counter punch.

  3. 5 CFR 330.706 - Notification of displaced employees.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Notification of displaced employees. 330... RECRUITMENT, SELECTION, AND PLACEMENT (GENERAL) Interagency Career Transition Assistance Plan for Displaced Employees § 330.706 Notification of displaced employees. (a) In addition to meeting the requirements of...

  4. Kinematic and ground reaction force accommodation during weighted walking.

    Science.gov (United States)

    James, C Roger; Atkins, Lee T; Yang, Hyung Suk; Dufek, Janet S; Bates, Barry T

    2015-12-01

    Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability. Copyright © 2015 Elsevier B

  5. 40 CFR 205.153 - Engine displacement.

    Science.gov (United States)

    2010-07-01

    ..., in accordance with American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine...

  6. Dissolved oxygen detection by galvanic displacement-induced

    Indian Academy of Sciences (India)

    Dissolved oxygen detection by galvanic displacement-induced graphene/silver nanocomposite ... dissolved oxygen (DO) detection based on a galvanic displacement synthesized reduced graphene oxide–silver nanoparticles ... Current Issue

  7. Predictors for Long-Term Hip Survivorship Following Acetabular Fracture Surgery: Importance of Gap Compared with Step Displacement.

    Science.gov (United States)

    Verbeek, Diederik O; van der List, Jelle P; Tissue, Camden M; Helfet, David L

    2018-06-06

    Historically, the greatest residual (gap or step) displacement is used to predict clinical outcome following acetabular fracture surgery. Gap and step displacement may, however, impact the outcome to different degrees. We assessed the individual relationship between gap or step displacement and hip survivorship and determined their independent association with conversion to total hip arthroplasty. Patients who had acetabular fracture fixation (from 1992 through 2014), follow-up of ≥2 years (or early conversion to total hip arthroplasty), and postoperative computed tomography (CT) scans were included. Of 227 patients, 55 (24.2%) had conversion to total hip arthroplasty at a mean follow-up (and standard deviation) of 8.7 ± 5.6 years. Residual gap and step displacement were measured using a standardized CT-based method, and assessors were blinded to the outcome. Kaplan-Meier survivorship curves for the hips were plotted and compared (log-rank test) using critical cutoff values for gap and step displacement. These values were identified using receiver operating characteristic curves. Multivariate analysis was performed to identify independent variables associated with conversion to total hip arthroplasty. Subgroup analysis was performed in younger patients (step displacement. Hip survivorship at 10 years was 82.0% for patients with a gap of step of step of ≥1.0 mm (p = 0.012). A gap of ≥5 mm (hazard ratio [HR], 2.3; p = 0.012) and an age of ≥50 years (HR, 4.2; p step of ≥1 mm (HR, 6.4; p = 0.017) was an independent factor for conversion to total hip arthroplasty. Residual gap and step displacement as measured on CT scans are both related to long-term hip survivorship, but step displacement (1 mm) is tolerated less than gap displacement (5 mm). Of the 2 types of displacement, only a large gap displacement (≥5 mm) was independently associated with conversion to total hip arthroplasty. In younger patients who had less articular impaction with smaller residual

  8. Study on Load-displacement Test of Rubber Pads of Coal Mine Roadway Constructed by Shield

    Science.gov (United States)

    Yang, Yue; Chen, Xiaoguo; Yang, Liyun

    2017-12-01

    Shield method construction of coal mine roadway is the future trend of the development of deep coal mining. The main shaft supporting is the segment. There is rubber pads between segment and segment. The performance of compression deformation of rubber pad is essential for the overall stability of lining. Through load test, displacement of the rubber pad under load, the thrust force law of the rubber pad deformation, and provide a theoretical basis for the stability analysis of coal mine tunnel shield construction.

  9. On configurational forces for gradient-enhanced inelasticity

    Science.gov (United States)

    Floros, Dimosthenis; Larsson, Fredrik; Runesson, Kenneth

    2018-04-01

    In this paper we discuss how configurational forces can be computed in an efficient and robust manner when a constitutive continuum model of gradient-enhanced viscoplasticity is adopted, whereby a suitably tailored mixed variational formulation in terms of displacements and micro-stresses is used. It is demonstrated that such a formulation produces sufficient regularity to overcome numerical difficulties that are notorious for a local constitutive model. In particular, no nodal smoothing of the internal variable fields is required. Moreover, the pathological mesh sensitivity that has been reported in the literature for a standard local model is no longer present. Numerical results in terms of configurational forces are shown for (1) a smooth interface and (2) a discrete edge crack. The corresponding configurational forces are computed for different values of the intrinsic length parameter. It is concluded that the convergence of the computed configurational forces with mesh refinement depends strongly on this parameter value. Moreover, the convergence behavior for the limit situation of rate-independent plasticity is unaffected by the relaxation time parameter.

  10. Measurement system for special surface mapping using miniature displacement sensors

    Directory of Open Access Journals (Sweden)

    Zowade Martyna

    2018-01-01

    Full Text Available The aim of the work was to design a special system for measurements of elements with repetitive geometry or assemblies with repeating components, set in a linear patterns. The main focus was based on developing a computer program for signal analysis from variable number of miniature displacement sensors. It was set that the response for displacement of measuring tip from each sensor was a 0-5 V voltage signal with possibility of using different type of sensors. Requirements were determined based on projected measurement method. A special design of sensor was made for testing the computer program. If the characteristics of the sensor is known, it is possible to compute the type A evaluation of uncertainty. The results are presented in XY chart on computer screen. The program allows the user to choose any number of the sensors and determine the distance between them. Also, the possibility of calibration of sensors’ set was provided. The test were conducted on a prototype handle for sensors, made on a 3D printer.

  11. Epidemiology of Substance Use among Forced Migrants: A Global Systematic Review.

    Directory of Open Access Journals (Sweden)

    Danielle Horyniak

    Full Text Available Forced migration is occurring at unprecedented levels. Forced migrants may be at risk for substance use for reasons including coping with traumatic experiences, co-morbid mental health disorders, acculturation challenges and social and economic inequality. This paper aimed to systematically review the literature examining substance use among forced migrants, and identify priority areas for intervention and future research.Seven medical, allied health and social science databases were searched from inception to September 2015 in accordance with PRISMA guidelines to identify original peer-reviewed articles describing any findings relating to alcohol and/or illicit drug use among refugees, internally displaced people (IDPs, asylum seekers, people displaced by disasters and deportees. A descriptive synthesis of evidence from quantitative studies was conducted, focusing primarily on studies which used validated measures of substance use. Synthesis of evidence from qualitative studies focused on identifying prominent themes relating to the contexts and consequences of substance use. Critical Appraisal Skills Programme (CASP checklists were used to assess methodological quality of included studies.Forty-four quantitative (82% cross-sectional, 16 qualitative and three mixed-methods studies were included. Ten studies were rated as high methodological quality (16%, 39 as moderate quality (62% and 14 as low quality (22%. The majority of research was conducted among refugees, IDPs and asylum seekers (n = 55, 87%, predominantly in high-income settings. The highest-quality prevalence estimates of hazardous/harmful alcohol use ranged from 17%-36% in camp settings and 4%-7% in community settings. Few studies collected validated measures of illicit drug use. Seven studies compared substance use among forced migrants to other migrant or native-born samples. Among eight studies which conducted multivariable analysis, male sex, trauma exposure and symptoms of

  12. The displaced and dispossessed of Darfur: explaining the sources of a continuing state-led genocide.

    Science.gov (United States)

    Hagan, John; Kaiser, Joshua

    2011-03-01

    The millions of survivors who fled from attacks to Sudanese-controlled displacement camps and the refugee camps in Chad are the living ghosts of the Darfur genocide. The 1948 Genocide Convention incorporates extermination by mass killing and elimination through forced migration as two distinct elements of genocide. Genocide scholars and public discourse emphasize extermination by killing, but they give far less explanatory attention to the elimination processes that the Genocide Convention describes as 'deliberately inflicting on the group conditions of life calculated to bring about its physical destruction'. (Article II United Nations 1948.) In Darfur, understanding the latter processes requires theoretical attention to the history of food, water, and famine and detailed methodological attention to temporal processes of displacement. We demonstrate how intentional state-led attacks on food and water massively dislodged Black Africans in Darfur from February 2003 to August 2004. The political leadership of the Sudanese state dehumanized and forcibly displaced Black Africans from their homes in Darfur to camps where they largely remain, not only through mass killings and rapes, but also by destroying life-sustaining access to food and water, leading to the genocidal elimination of group life in this region. © London School of Economics and Political Science 2011.

  13. Forces on particles in microstreaming flows

    Science.gov (United States)

    Hilgenfeldt, Sascha; Rallabandi, Bhargav; Thameem, Raqeeb

    2015-11-01

    In various microfluidic applications, vortical steady streaming from ultrasonically driven microbubbles is used in concert with a pressure-driven channel flow to manipulate objects. While a quantitative theory of this boundary-induced streaming is available, little work has been devoted to a fundamental understanding of the forces exerted on microparticles in boundary streaming flows, even though the differential action of such forces is central to applications like size-sensitive sorting. Contrary to other microfluidic sorting devices, the forces in bubble microstreaming act over millisecond times and micron length scales, without the need for accumulated deflections over long distances. Accordingly, we develop a theory of hydrodynamic forces on the fast time scale of bubble oscillation using the lubrication approximation, showing for the first time how particle displacements are rectified near moving boundaries over multiple oscillations in parallel with the generation of the steady streaming flow. The dependence of particle migration on particle size and the flow parameters is compared with experimental data. The theory is applicable to boundary streaming phenomena in general and demonstrates how particles can be sorted very quickly and without compromising device throughput. We acknowledge support by the National Science Foundation under grant number CBET-1236141.

  14. Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Enrique Vidal

    2013-08-01

    Full Text Available The Wavestar Wave Energy Converter (WEC is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO system, converting the wave induced motion of the floats into a steady power output to the grid. In the present work, a PTO based on a novel discrete displacement fluid power technology is explored for the Wavestar WEC. Absorption of power from the floats is performed by hydraulic cylinders, supplying power to a common fixed pressure system with accumulators for energy smoothing. The stored pressure energy is converted into electricity at a steady pace by hydraulic motors and generators. The storage, thereby, decouples the complicated process of wave power absorption from power generation. The core for enabling this PTO technology is implementing a near loss-free force control of the energy absorbing cylinders. This is achieved by using special multi-chambered cylinders, where the different chambers may be connected to the available system pressures using fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC is created, allowing near loss free discrete force control. This paper presents a complete PTO system for a 20 float Wavestar based on the DDC. The WEC and PTO is rigorously modeled from incident waves to the electric output to the grid. The resulting model of +600 states is simulated in different irregular seas, showing that power conversion efficiencies above 70% from input power to electrical power is achievable for all relevant sea conditions.

  15. Proximity and Force Characteristics of CMC Touch Sensor with Square/Dome-shaped Sensor Elements

    International Nuclear Information System (INIS)

    Kawamura, T; Inaguma, N; Kakizaki, Y; Yamada, H; Tani, K

    2013-01-01

    A tactile sensor called Carbon Micro Coil (CMC) touch sensor was developed by CMC Technology Development Co., Ltd. The sensor's elements used in the experiments of this paper are made of silicon rubber containing CMCs several micrometers in diameter. One of the elements is molded into a square 30 mm on a side and 3 mm thick; the other is a dome 16 mm in diameter and 2 mm height. CMCs in the sensor element contribute to the electrical conductivity and the sensor element is considered to constitute an LCR circuit. When an object approaches to the sensor element or the sensor element is deformed mechanically, the impedance changes, and the CMC sensor detects the impedance changes by measuring the modulation of amplitude and phase of an input excitation signal to the sensor element. The CMC sensor also creates voltage signals of the R- and LC-components separately according to the amplitude and phase modulation. In this paper, the characteristics of the CMC sensor with respect to its proximity and force senses are investigated. First, the output of the CMC sensor with the square-shaped sensor element is measured when an object approaches to the sensor element. Next, the output of the CMC sensor with the dome-shaped sensor element is measured when fine deformations of 1 to 5 μm are applied to the sensor element under variable compression force. The results suggest that the CMC sensor can measure the force variance applied to the sensor element as well as the distance between the sensor element and an object.

  16. Analysis of Statoliths Displacement in Chara Rhizoids for Validating the Microgravity-Simulation Quality of Clinorotation Modes

    Science.gov (United States)

    Krause, Lars; Braun, Markus; Hauslage, Jens; Hemmersbach, Ruth

    2018-05-01

    In single-celled rhizoids of the green algae Chara, positively gravitropic growth is governed by statoliths kept in a dynamically stable position 10-25 μ m above the cell tip by a complex interaction of gravity and actomyosin forces. Any deviation of the tube-like cells from the tip-downward orientation causes statoliths to sediment onto the gravisensitive subapical cell flank which initiates a gravitropic curvature response. Microgravity experiments have shown that abolishing the net tip-directed gravity force results in an actomyosin-mediated axial displacement of statoliths away from the cell tip. The present study was performed to critically assess the quality of microgravity simulation provided by different operational modes of a Random Positioning Machine (RPM) running with one axis (2D mode) or two axes (3D mode) and different rotational speeds (2D), speed ranges and directions (3D). The effects of 2D and 3D rotation were compared with data from experiments in real microgravity conditions (MAXUS sounding rocket missions). Rotational speeds in the range of 60-85 rpm in 2D and 3D modes resulted in a similar kinetics of statolith displacement as compared to real microgravity data, while slower clinorotation (2-11 rpm) caused a reduced axial displacement and a more dispersed arrangement of statoliths closer to the cell tip. Increasing the complexity of rotation by adding a second rotation axis in case of 3D clinorotation did not increase the quality of microgravity simulation, however, increased side effects such as the level of vibrations resulting in a more dispersed arrangement of statoliths. In conclusion, fast 2D clinorotation provides the most appropriate microgravity simulation for investigating the graviperception mechanism in Chara rhizoids, whereas slower clinorotation speeds and rotating samples around two axes do not improve the quality of microgravity simulation.

  17. A feasibility study for experimentally determining dynamic force distribution in a lap joint

    Energy Technology Data Exchange (ETDEWEB)

    Mayes, Randall Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-11-01

    Developing constitutive models of the physics in mechanical joints is currently stymied by inability to measure forces and displacements within the joint. The current state of the art estimates whole joint stiffness and energy loss per cycle from external measured force input and one or two acceleration responses. To validate constitutive models beyond this state requires a measurement of the distributed forces and displacements at the joint interface. Unfortunately, introducing measurement devices at the interface completely disrupts the desired physics. A feasibility study is presented for a non-intrusive method of solving for the interface dynamic forces from an inverse problem using full field measured responses. The responses come from the viewable surface of a beam. The noise levels associated with digital image correlation and continuous scanning laser Doppler velocimetry are evaluated from typical beam experiments. Two inverse problems are simulated. One utilizes the extended Sum of Weighted Accelerations Technique (SWAT). The second is a new approach dubbed the method of truncated orthogonal forces. These methods are much more robust if the contact patch geometry is well identified. Various approaches to identifying the contact patch are investigated, including ion marker tracking, Prussian blue and ultrasonic measurements. A typical experiment is conceived for a beam which has a lap joint at one end with a single bolt connecting it to another identical beam. In a virtual test using the beam finite element analysis, it appears that the SWAT inverse method requires evaluation of too many coefficients to adequately identify the force distribution to be viable. However, the method of truncated orthogonal forces appears viable with current digital image correlation (and probably other) imaging techniques.

  18. Towards quantitative determination of the spring constant of a scanning force microscope cantilever with a microelectromechanical nano-force actuator

    International Nuclear Information System (INIS)

    Gao, Sai; Herrmann, Konrad; Zhang, Zhikai; Wu, Yong

    2010-01-01

    The calibration of the performance of an SFM (scanning force microscope) cantilever has gained more and more interest in the past years, particularly due to increasing applications of SFMs for the determination of the mechanical properties of materials, such as biological structures and organic molecules. In this paper, a MEMS-based nano-force actuator with a force resolution up to nN (10 −9 N) is presented to quantitatively determine the stiffness of an SFM cantilever. The principle, structure design and realization of the nano-force actuator are detailed. Preliminary experiments demonstrate that the long-term self-calibration stability of the actuator is better than 3.7 × 10 −3 N m −1 (1σ) over 1 h. With careful calibration of the stiffness of the actuator, the MEMS actuator has the capability to determine the stiffness of various types of cantilevers (from 100 N m −1 down to 0.1 N m −1 ) with high accuracy. In addition, thanks to the large displacement and force range (up to 8 µm and 1 mN, respectively) of the actuator, the calibration procedure with our MEMS nano-force actuator features simple and active operation, and therefore applicability for different types of quantitative SFMs

  19. Study of damping characteristics of fibre reinforced composite aerospace structure

    International Nuclear Information System (INIS)

    Khan, M.Z.; Saleh, S.; Munir, A.

    2006-01-01

    Composite materials are used in a variety of high demanding structural applications. Apart from their other preferable properties, they have high-energy dissipation characteristics, which is important aspect when we repeatedly wiggle the system back and forth. It is important to have thorough understanding of material damping behavior; in general materials damping tends to be complex nonlinear function of vibration amplitude, frequency of loading and material formulation. There are number of mathematical models available in literature to obtain hysteresis curves. One approach for identifying damping characteristics used mechanical hysteresis curves. In present work, a phenomenon was observed during testing of fibre reinforced composite beam of an aerospace structure, that for increase load in structure, the path of Force vs. Displacement curve is different than the path of unloading. A plot is generated which indicate the hysteresis loop representing the steady state dynamic behavior of material. The area enclosed by such curves is proportional to energy dissipation per cycle. However, the specific shape of the curve also has important implications for characterizing the specific functional form of the damping. Therefore, it is important to develop methods for accurately accounting for such effects. The current work explores the damping characteristics both theoretically and experimentally. (author)

  20. Exploring children's movement characteristics during virtual reality video game play.

    Science.gov (United States)

    Levac, Danielle; Pierrynowski, Michael R; Canestraro, Melissa; Gurr, Lindsay; Leonard, Laurean; Neeley, Christyann

    2010-12-01

    There is increasing interest in the use of commercially-available virtual reality video gaming systems within pediatric rehabilitation, yet little is known about the movement characteristics of game play. This study describes quantity and quality of movement during Nintendo Wii and Wii Fit game play, explores differences in these movement characteristics between games and between novice and experienced players, and investigates whether motivation to succeed at the game impacts movement characteristics. Thirty-eight children (aged 7-12) with and without previous game experience played Wii (boxing and tennis) and Wii Fit (ski slalom and soccer heading) games. Force plate data provided center of pressure displacement (quantity) and processed pelvis motion indicated smoothness of pelvic movement (quality). Children rated their motivation to succeed at each game. Movement quantity and quality differed between games (pgames demonstrated greater movement quantity during Wii Fit game play (p<.001); quality of movement did not differ between groups. Motivation to succeed did not influence the relationship between experience and outcomes. Findings enhance clinical understanding of this technology and inform the development of research questions to explore its potential to improve movement skills in children with motor impairments. Copyright © 2010 Elsevier B.V. All rights reserved.